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MEDICAL *CInIL 
 
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THE 
 
 PRACTICAL ANATOMIST. 
 
THE 
 
 PRACTICAL ANATOMIST; 
 
 OR, 
 
 THE STUDENT'S GUIDE IN THE DISSECTING-ROOM, 
 
 BY 
 
 J. M. ALLEN, M. D., 
 
 LATE PROFESSOR OF ANATOMY IX THE MEDICAL DEPARTMENT OP PENNSYLVANIA COLLEGE j 
 FELLOW OF THE COLLEGE OF PHYSICIANS ; MEMBER OF THE ACADEMY OF 
 NATURAL SCIENCES, ETC. 
 
 WITH 
 
 TWO HUNDRED AND SI-XT Y- SIX ILLUSTRATIONS. 
 
 PHILADELPHIA:, 
 
 BLANCHAKD AND LEA 
 
 1856. 
 
Entered according to the Act of Congress, in the year 1856, by 
 BLANCHARD AND LEA, 
 
 in the Office of the Clerk of the District Court of the United States in and 
 for the Eastern District of Pennsylvania. 
 
 PHILADELPHIA : 
 T. K. AND P. . COLLINS, PRINTERS. 
 
PREFACE. 
 
 IN preparing a Treatise on Practical Anatomy for the use 
 of medical students, I have not been influenced by the hope 
 that I should be able to add anything new to the fund of 
 knowledge which is to be found in the various works which 
 have been written on anatomy; nor have I expected to be 
 able to introduce much that would be new to any one who 
 has had much experience in teaching practical anatomy. 
 
 As our medical institutions are now organized, the student 
 must expect to obtain his knowledge of anatomy from two 
 distinct sources namely, the anatomical theatre, and the dis- 
 secting-room. In the anatomical theatre, he is taught ana- 
 tomy ^after whatever plan is adopted by the Professor of that 
 department in the institution with which he happens to be 
 connected. Here, every part requiring dissection passes 
 through the hands of the Prosector before it is presented to 
 him for his inspection, all the parts not at the time under 
 consideration having been removed. In this way, the stu- 
 dent is taught anatomy systematically ; he has each system, 
 as the muscular, the vascular, &c., presented to him by itself. 
 He is also provided with what is called a text-look, in which he 
 finds everything presented in the same order as in the lecture- 
 room. Thus, in learning anatomy in this way, he is required 
 to do but little more than to listen to what is told him, to ob- 
 serve the illustrations employed by the lecturer, and to read 
 his text-book. 
 
 13452 
 
VI PREFACE. 
 
 That some parts of anatomy can be taught to better ad- 
 vantage in the anatomical theatre than elsewhere there can 
 be no doubt. But there are other parts that can be learned 
 far better in the dissecting-room. Among the parts thus 
 learned may be included almost everything, whose relations 
 must be understood in order to render a knowledge of them 
 available in diagnosis and in operative surgery. 
 
 However desirable it may be to have every student become 
 a thorough anatomist, it must be well known to every teacher 
 of anatomy that much of what is taught in the lecture-room 
 is never fully learned and retained by very many of those who 
 graduate in our best institutions ; nor is it necessary that the 
 practitioner of medicine or surgery should be so thoroughly 
 conversant with the science of anatomy as he who teaches 
 it. Yet no one, I presume, will say that the student should 
 not learn as much of anatomy as is essential to enable him 
 to do justice to those who may confide in his skill or his 
 ability to treat disease. As but few of those who enroll their 
 names in our colleges as students can ever desire or hope to 
 become teachers of anatomy, it is important .that their time 
 should be appropriated to the study of what will be indis- 
 pensable for them to know in the daily routine of practice. 
 Impressed with the conviction that the dissecting-room affords 
 the greatest facilities for acquiring that knowledge which 
 the student, when he becomes a practitioner of medicine, will 
 most need, I have endeavored to supply him with what might 
 be regarded as his text-book in the dissecting-room. 
 
 To be a student in the lecture-room is quite different from 
 being a student in the dissecting-room. In the latter, the body 
 is placed in his hands without any previous dissection having 
 been made, and he is required to dissect each part himself. 
 To do this, he must avail himself of the experience of some 
 one who is familiar not only with the parts to be dissected, 
 but with the manipulations necessary to make the proper 
 dissections. In offering him this assistance, I have not viewed 
 
PREFACE. Vll 
 
 him as a mere passive agent, but as one capable of using his 
 own faculties, and of exercising his own skill and judgment 
 as occasion might require. It has been my constant aim to 
 instil in the dissecting-room a feeling of self-reliance and 
 self-dependence; to make the student feel that when he had 
 exposed a part, as a muscle, for example, he could see and 
 learn its relations to surrounding parts just as well with- 
 out as with being told them ; that he could see with his own 
 eyes whether a muscle lies on the outer or inner side of a 
 particular artery, and whether it must be divided or not in 
 cutting down upon the latter for the purpose of applying a 
 ligature to it, or whether it may serve as a guide for finding 
 the vessel, and, if so, rn what way. In following out this 
 plan, I have, whenever the opportunity offered, suggested 
 what deserved his special attention, believing that a simple 
 suggestion would often be of more value to him than a whole 
 page occupied in describing what a mere hint would prompt 
 him to ascertain or learn without assistance. Whenever I 
 have been able, in the dissecting-roorn, to make a student 
 feel a consciousness of his own ability to become a good 
 practical anatomist, I have almost invariably had the grati- 
 fication of witnessing his entire success. For the truth of 
 this remark, I can appeal to hundreds of gentlemen who 
 are at this time engaged in the active duties of professional 
 life in different portions of the United States. 
 
 In the dissecting-room, more than in almost any other 
 place, the student should be encouraged to cultivate a habit 
 of self -interrogation; to ask himself the use of everything he 
 dissects, and in what way a knowledge of it can be made 
 available to him, either in understanding the other branches 
 of medical science or in his future practice. To incite in his 
 mind such a spirit of self- inquiry has been my constant en- 
 deavor throughout the work. 
 
 In the division of a subject, I have followed the plan 
 which I have found, after a trial of many years, to be the 
 
Vlll PREFACE. 
 
 most convenient and advantageous to students, whose time 
 for studying practical anatomy is limited, and who, not un- 
 frequently, are compelled to confine their dissections to one 
 or two bodies during the session. The body is supposed to be 
 divided into five parts, and apportioned to as many persons; 
 one of whom has the head and neck, two have, each an upper 
 extremity separately, and the thorax in common; two have, 
 each a lower extremity, including the abdominal and pelvic 
 viscera between them. It is expected that all will partici- 
 pate in the examination of the parts contained in the three 
 great splanchnic cavities, as they cannot be divided. 
 
 Mere arbitrary rules for exposing the parts in any region 
 have been, in general, avoided ; the position and the relations 
 of each organ or part have indicated the method that has 
 been adopted for dissecting it. Every part in a region has 
 been noticed as it would naturally be met with when the 
 student was desirous of studying everything contained in 
 that region. 1 have found, that when the attention of a 
 student was directed to the relations of a part as well as to 
 the part itself, the recollection of the one usually aided him 
 in the recollection of the other; that it was merely necessary 
 for him to appropriate more time to the study of the parts 
 of that region. 
 
 In aiming to make the book as useful as possible, viewing 
 the student as a candidate for the practice of medicine and 
 surgery, I have not hesitated to discriminate, to some ex- 
 tent, between different regions and organs in a practical point 
 of view; hence, I have dwelt longer on some parts than on 
 others, being governed in this respect partly by what I con- 
 ceived to be the relative value and importance of the know- 
 ledge of any part or organ to the student, and partly by the 
 difficulty which I have observed students in the dissecting- 
 room, especially beginners, to have in dissecting and under- 
 standing them. Thus, I have devoted a large share of time 
 and space to the organs contained in the three great splanch- 
 
PREFACE. IX 
 
 nic cavities, to the organs of the special senses, and to such 
 regions as the perineum, the inguinal, the femoral, the ante- 
 rior part of the neck, and the axilla. Although the space 
 allowed in the original plan of the book did not admit of my 
 dwelling long on the medical and surgical anatomy of many 
 parts and regions, I have endeavored to direct the attention 
 of the student to whatever had a practical bearing, so that he 
 could, by referring to works on medicine and surgery, derive 
 full advantage from his dissections. To give merely a meagre 
 or superficial account of the medical and surgical anatomy of 
 a part, I am satisfied, does the student more harm than good. 
 
 There has necessarily been in some places more or less 
 repetition. As the dissector wishes merely to know the posi- 
 tion and the relations of a part in the region that he is dis- 
 secting, the same part, in some instances, is referred to at 
 different times, and in different dissections. 
 
 In regard to illustrations, I need only say that the Pub- 
 lishers gave me carte-blanche to select from the whole number 
 of drawings contained in the various works which have been 
 published by them. When the value of these illustrations 
 over two hundred and sixty in number is considered, I am 
 confident that the liberality thus manifested by them will be 
 duly appreciated by every one who may avail himself of the 
 work. There is no Dissector, as far as my knowledge extends, 
 which is so fully illustrated as this ; it is hardly possible to 
 over-estimate the value of pictorial illustrations in a work on 
 practical anatomy. I may be permitted to say that the Pub- 
 lishers have spared no expense to make the work, as far as 
 it depended on them, in every way acceptable to the medical 
 student. 
 
 The artistical appearance of the work speaks the praise of 
 those who have had the execution of it in their charge. 
 
 It affords me sincere pleasure to avail myself of this oppor- 
 tunity to express my heartfelt thanks to those Gentlemen who, 
 while my Pupils, aided me in various ways in examining dif- 
 
X PREFACE. 
 
 ferent parts of the body for the purpose of extending my ob- 
 servations in the science of anatomy. Among them, I am 
 happy to speak especially of the labors of H. M. Keynolds,' 
 M. D., who labored most assiduously for upwards of two 
 years as my assistant, principally in making special dissections. 
 To W. H. GOBKECHT, M. D., late Demonstrator of Ana- 
 tomy in the Medical Department of Pennsylvania College, 
 I am under very great obligations for the able and valuable 
 assistance he has rendered me in revising .and correcting the 
 sheets as they have passed through the press. 
 
 Although the work has been prepared more especially for 
 the student in the dissecting-room, I feel confident that the 
 physician will find it adapted to his wants, whenever he may 
 wish to refresh his memory on the position and relations of 
 
 any part or organ. 
 
 J. M. ALLEN. 
 
 PHILADELPHIA, October, 1856. 
 
TABLE OF CONTENTS. 
 
 GENERAL REMARKS . . ... . . . .25 
 
 PART i. 
 
 DISSECTION OF THE HEAD AND NECK. 
 CHAPTER I. 
 
 OF THE HEAD. 
 
 SECTION I. 
 Of the Face . . 29 40 
 
 SECTION II. 
 Appendages of the Eye outside of the orbit . . 40 4? 
 
 SECTION III. 
 Dissection of the Soft parts on the upper part of the Cranium 4t 52 
 
 * 
 
 SECTION IV. 
 
 Dissection of the Membranes of the Brain 52 56 
 
Xll 
 
 TABLE OF CONTENTS. 
 
 SECTION V. 
 
 Dissection of the Brain 
 
 Origin of the Cerebral Nerves . 
 Arteries of the Brain 
 
 Dura mater 
 
 56 
 
 80 
 85 
 90 
 
 SECTION VI. 
 Dissection of the Appendages of the Eye within the orbit 91 99 
 
 SECTION VII. 
 
 The Eyeball . 
 
 SECTION IX. 
 
 Dissection of the Ear 
 
 SECTION X. 
 Dissection of the Nose . . 
 
 SECTION XL 
 Topography of the Mouth, Fauces, and Pharynx 
 
 SECTION XII. 
 Dissection of the Palate . ... 
 
 SECTION XIII. 
 
 99110 
 
 SECTION VIII. 
 The Spheno-maxillary region ..... 110 120 
 
 Dissection of the Tongue 
 
 120134 
 
 134143 
 
 143150 
 
 150152 
 
 152155 
 
TABLE OF CONTENTS, 
 
 Xlll 
 
 CHAPTER II. 
 
 DISSECTION OF THE NECK. 
 
 SECTION I. 
 Superficial parts of the Neck . 
 
 SECTION II. 
 Dissection of the Deep parts of the Neck 
 
 SECTION III. 
 Dissection of the Larynx .... 
 
 SECTION IY. 
 Dissection of the Pharynx 
 
 155184 
 
 184192 
 
 192203 
 
 203205 
 
 PART II. 
 
 DISSECTION OF THE THORAX, BACK, AND UPPER EXTREMITY. 
 
 CHAPTER I. 
 
 * 
 
 THE UPPER EXTREMITY. 
 
 SECTION I. 
 Dissection of the Pectoral and Axillary regions . 20t 223 
 
 SECTION II. 
 Dissection of the Back 223238 
 
 SECTION III. 
 Dissection of the Shoulder . . 238 245 
 
XIV TABLE OF CONTENTS. 
 
 SECTION IV. 
 
 Dissection of the Arm 245 286 
 
 The Palm of the Hand 2?3 281 
 
 SECTION Y. 
 
 Dissection of the Spinal Canal and its Contents . 28G 290 
 
 CHAPTER II. 
 
 OF THE THORAX AND ITS CONTENTS. 
 
 SECTION I. 
 
 Dissection of the Thorax 291 
 
 The Pleurae 295 
 
 " Pericardium 298 
 
 " Heart 299 
 
 " Mediastinum . . . . . . 315 
 
 " Lungs 325 
 
 " Ligaments of the Thorax 334 
 
 PART III. 
 
 DISSECTION OF ABDOMEN AND LOWER EXTREMITIES. 
 CHAPTER I. 
 
 OP THE ABDOMEN. 
 
 SECTION I. 
 
 Parietes of the Abdomen 339360 
 
 Anatomy of Inguinal Hernia .... 349 35*7 
 
TABLE OF CONTENTS. 
 
 XV 
 
 SECTION II. 
 
 Dissection of the Cavity of the Abdomen 
 Relations of the Abdominal Yiscera 
 Yessels and Nerves of the Yiscera 
 Dissection of the Yiscera . 
 
 360420 
 366375 
 375386 
 386410 
 
 SECTION III. 
 
 Dissection of the Pelvic Yiscera .... 420 474 
 Relations of the Pelvic Yiscera in the Male . 435 439 
 Dissection of the Yessels and Nerves iu the Pel- 
 vic cavity 439455 
 
 Dissection of the Perineum 455 474 
 
 SECTION IY. 
 Dissection of the Female Organs of Generation 
 
 474489 
 
 CHAPTER II. 
 
 OF THE LOWER EXTREMITY. 
 
 SECTION I. 
 
 Dissection of the Anterior part of the Thigh 
 Anatomy of Femoral Hernia 
 
 489510 
 489500 
 
 SECTION II. 
 
 The Gluteal Region 511520 
 
 Dissection of the Hip-joint ..... 520 
 
 " Articulations of the Yertebraa . 525 
 
 Pelvis 535 
 
 SECTION III. 
 Dissection of the Back of the Thigh and of the Ham 539552 
 
XVI TABLE OF CONTENTS. 
 
 SECTION IY. 
 
 Dissection of the Posterior and the Inner part of the 
 
 Leg 552 56T 
 
 SECTION V. 
 
 Dissection of the Anterior and Outer parts of the 
 
 Leg, and the Dorsum of the Foot . . . 568582 
 
 SECTION VI. 
 Dissection of the Sole of the Foot .... 582595 
 
 SECTION VII. 
 Dissection of the Ligaments of the Knee, Leg, and Foot 595 616 
 
LIST OF ILLUSTRATIONS. 
 
 FIG. PAGE 
 
 1 . External Carotid Artery and its Branches . . . .30 
 
 2. Veins of the Head and Neck . . . . . .31 
 
 3. Salivary Glands, in sitft . ..... 33 
 
 4. Front View of the Left Eye . .... 40 
 
 5. Tensor Tarsi Muscle ....... 42 
 
 6. Meibomian Glands ....... 43 
 
 7. Lachrymal Apparatus and Nasal Duct . . . . .46 
 
 8. Sinuses of the Dura Mater . . . . . .54 
 
 9. Vertical Section of Cranium, showing the Falx Cerehri, Tentorium, etc. 56 
 
 10. Vertical Section in the median plane, of the Cerebrum, Cerebellum, 
 
 Pons, and Medulla Oblongata . . . . . .58 
 
 11. Section of Cerebrum, displaying the Lateral Ventricles . . .60 
 
 12. Section of the Cerebral Hemisphere . . . . .62 
 
 13. Section of the Cerebrum displaying the Surfaces of the Corpora Striata 
 
 and Optic Thalami, the Cavity of the Third Ventricle, and the Upper 
 Surface of the Cerebellum . . . . . .65 
 
 14. Superior Surface of the Cerebellum . . . . .70 
 
 15. Inferior Surface of the Cerebellum and a portion of the Medulla Ob- 
 
 longata ......... 71 
 
 16. Arbor Vitce and the Fundamental Portion of the Cerebellum . . 72 
 
 17. Base of the Cerebrum and Cerebellum, with Cranial Nerves . . 76 
 
 18. Arteries at the Base of the Brain . . . . .86 
 
 19. Sinuses at the Base of the Brain . . . . . .89 
 
 20. The Nerves in the Orbit above the Muscles . . . .92 
 
 21. The Deep Nerves of the Orbit . . . . . .93 
 
 22. Third, Fourth, and Sixth Pairs of Nerves . . . .95 
 
 23. Muscles of the Eyeball ....... 97 
 
 24. Transverse Section of the Cavernous Sinus of the Right Side . . 99 
 
 25. Longitudinal Section of the Globe of the Eye . . . .101 
 
 26. Ciliary Nerves . . . . . . . .104 
 
 27. Anterior Segment of a Transverse Section of the Globe of the Eye . 107 
 
 28. Posterior Segment of a Transverse Section of the Globe of the Eye . 108 
 
 2* 
 
XVlll LIST OF ILLUST11ATIONS. 
 
 FIG. PAGE 
 
 29. Side View of the adult Crystalline Lens . . . . .109 
 
 30. Triple Division of the Lens and the Course of its Fibres . . 109 
 
 31. Lens hardened in spirit and partially divided along the three Interior 
 
 Planes ......... 110 
 
 32. The two Pterygoid Muscles . . . . . . 11'2 
 
 33. Internal Maxillary Artery . . . . . ..114 
 
 34. External View of the Articulation of the Lower Jaw . . .115 
 
 35. Internal View of the Articulation of the Lower Jaw . . . 116 
 
 36. Section of Temporo-maxillary Articulation .... 116 
 
 37. Distribution of the Trifacial, or Fifth Pair . . . .118 
 
 38. Left Ear in its natural state . . . . . .121 
 
 39. Cartilage of the External Ear with some of its Muscles . . . 122 
 
 40. Membrana Tympani . . . . . . . 123 
 
 41. Diagram of the Ear . . . . . . . 125 
 
 42. Ossicles of the Left Ear . . . . . . .126 
 
 43. External Face of the Bony Labyrinth of the Left Side . . .129 
 
 44. Labyrinth in an inverted position ..... 132 
 
 45. Tympanic Nerve . . . . . . . .133 
 
 46. Cartilages of the Nose, seen from below ..... 135 
 
 47. Bones and Cartilages of the outer Nose ..... 135 
 
 48. Front View of the Cartilages of the Nose . . . .135 
 
 49. Osseous and Cartilaginous Septum of the Nose . . . .336 
 
 50. Outer Wall of the Left Nasal Fossa . . . . .137 
 
 51. Vertical Section of the Middle Part of the Nasal Fossse . . . 139 
 
 52. First Pair or Olfactory Nerves ...... 141 
 
 53. The Tongue, in sitft ....... 145 
 
 54. The Tongue, with its Papillae . . . . . .346 
 
 55. Median Section of the Nose, Mouth, Pharynx, and Larynx . . 147 
 
 56. Muscles of the Soft Palate, seen from below and in front . . 151 
 
 57. Posterior View of the Muscles of the Soft Palate . . .151 
 
 58. Dorsum of the Tongue ....... 153 
 
 59. Muscles of the Tongue, seen from its lower surface . . . 353 
 
 60. Under Surface of the Tongue and Muscles connected with it . . 154 
 
 61. Side View of the Superficial Layer of Muscles on the Face and Neck . 157 
 
 62. Side View of the Superficial Arteries and Veins of the Face and Neck . 159 
 
 63. Facial Nerve and Branches of the Cervical Plexus . . .160 
 
 64. Deep-seated Layer of Muscles on the Face and Neck . . . 164 
 
 65. Arteries of the Neck and Shoulder ..... 169 
 
 66. The Heart, with the Great Vessels of the Neck, in sitft . . .171 
 
 67. Hypoglossal or Ninth Pair of Nerves and Deep-seated Nerves of Neck . 173 
 
 68. Vertebral Artery, Carotid and Arch of the Aorta . . .174 
 
 69. Superficial and Deep Muscles of the Anterior Aspect of the Neck . 178 
 
 70. Nerves of the Tongue, etc. ...... 180 
 
 71. Prcevertebral Group of Muscles of the Neck .... 190 
 
 72. Anterior View of the Os Hyoides ..... 193 
 
 73. Front View of the Cricoid Cartilage ... .194 
 
LIST OF ILLUSTRATIONS. XIX 
 
 74. Lateral View of the Thyroid Cartilage . . . . .195 
 
 75. Anterior View of the Left Arytenoid Cartilage . . . .196 
 
 76. Posterior View of the Left Arytenoid Cartilage . . . .196 
 
 77. Lateral View of the Epiglottis' . . . . . .196 
 
 78. Posterior View of the Articulations of the Cartilages of the Larynx . 198 
 
 79. Front View of the Ligaments of the Larynx . . . .198 
 
 80. Lateral View of the Ligaments of the Larynx . . ... 199 
 
 81. The Larynx from above ....... 199 
 
 82. Front View of the Crico-Thyroid Muscles . . . .200 
 
 83. Posterior View of the Arytenoid and Crico-Arytenoid Muscles . 200 
 
 84. Vertical Section of the Larynx to show some of its Muscles . . 201 
 
 85. Vertical Section of the Larynx, to show its Internal Surface . . 202 
 
 86. Posterior View of the Muscles of the external portion of the Pharynx . 204 
 
 87. Side View of the Muscles of the Pharynx . . . .205 
 
 88. Side View of the Mammary Gland . . . . .208 
 
 89. Vertical Section of the Mammary Gland . . . .209 
 
 90. Superficial Muscles of the Upper Front of the Trunk . . .211 
 
 91. Deeper-seated ^uscles on the Upper Front of the Trunk . . 214 
 
 92. Axillary and Bracl/^al Arteries and their Branches . . . 216 
 
 93. Brachial Plexus of 'Nerves and Branches to the Arm . . .217 
 
 94. Superficial Veins on the Front of the Upper Extremity . . . 219 
 
 95. Lateral View of the Deep-seated Muscles of the Trunk . . 220 
 
 96. Anterior View of the Muscles of the Shoulder . . . .222 
 
 97. First and Second and Part of the Third Layers of Muscles of the Back 226 
 
 98. Fourth and Fifth, and Part of the Sixth Layers of the Muscles of the 
 
 Back . . . . . . . . .231 
 
 99. The Deltoid Muscle . . . . . . .239 
 
 100. Posterior View of the Muscles of the Shoulder with the Deltoid . 240 
 
 101. Posterior View of the Muscles of the Shoulder which strengthen the 
 
 Articulation ........ 241 
 
 102. The Ligaments of the Scapula and Shoulder-Joint . . .243 
 
 103. Plan of the Cutaneous Nerves on the Front of the Arm . . 247 
 
 104. 'Plan of the Cutaneous Nerves of the Back of the Arm and Forearm . 247 
 
 105. Superficial Veins at the Bend of the Arm . . . , . 248 
 
 106. Fascia Brachialis . . . . . . .249 
 
 107. Muscles on the Front of the Arm . . . . .250 
 
 108. Plan of the Nerves of the Arm . . . . . .251 
 
 109. Anterior View of the Deep-seated Muscles of the Arm . . .255 
 
 110. Lateral View of the Deep-seated Muscles on the back of the Arm . 256 
 
 111. Superficial Layer of the Muscles of the Forearm . . . 260 
 
 112. The Arteries of the Forearm . . . . . .262 
 
 113. Nerves on the Front of the Forearm . - . . . . 265 
 
 114. Deep Layer of Muscles of the Forearm . . . . .266 
 
 115. The Pronators of the Forearm ...... 267 
 
 116. Superficial Layer of Muscles of the Posterior Aspect of the Forearm . 269 
 
 117. Deep Lnycr of Muscles on the Posterior Aspect of the Forearm . 270 
 
XX LIST OF ILLUSTRATIONS. 
 
 FIG. PAGE 
 
 118. Nerves on the Back of the Forearm and Hand .... 271 
 
 119. Muscles of the Hand . . . , . . .277 
 
 120. Palmar Interosseous Muscles ...... 280 
 
 121. Dorsal Interosseous Muscles ...... 280 
 
 122. Internal View of the Elbow-Joint . . . . .282 
 
 123. External View of the Elbow-Joint . . . . .282 
 
 124. Ligaments of the Anterior Aspect of the Wrist and Hand . 284 
 
 125. Diagram of the Five Synovial Membranes of the Wrist-Joint . . 285 
 
 126. Anterior View of the Spinal Marrow . . . . .288 
 
 127. Portion of the Spinal Marrow, with origins of Spinal Nerves . . 289 
 
 128. Transverse Sections of the Spinal Cord . . . . .290 
 
 129. Diagram of the Thoracic Mediastina ..... 297 
 
 130. Anterior View of the Heart and its Vessels . . . .301 
 
 131. Posterior View of the Heart " " " . . . .301 
 
 132. The Right Auricle and Ventricle of the Heart laid open . .303 
 
 133. The Left Auricle and Ventricle of the Heart laid open . . 307 
 
 134. Parts of the Left Ventricle and Aorta laid open, showing the Sigmoid 
 
 Valves ......... 309 
 
 135. Auriculo-Venti'icular and Arterial Valves . . . .311 
 
 136. Posterior View of the External Muscular Layer of the Heart . . 313 
 
 137. The Large Vessels which proceed from the Root of the Heart, with 
 
 their Relations . . . . . . . .319 
 
 138. The Larynx, Trachea, and Bronchi . . . . .323 
 
 139. Anatomy of the Heart and Lungs . . . . .327 
 
 140. Portion of the (Esophagus of an Adult . . . . .328 
 
 141. Course and Termination of the Thoracic Duct . . . .331 
 
 142. The Great Sympathetic Nerve . . . . . .332 
 
 143. Ligaments of the Sterno-Clavicular and Costo-Sternal Articulations . 335, 
 
 144. Anterior Ligaments of the Vertebrae and Ligaments of the Ribs . 336 
 
 145. Posterior Ligaments of the Thoracic Portion of the Vertebral Column 
 
 and of the Ribs . . . . . . . .336 
 
 146. Superficial and Deep Muscles of the Anterior aspect of the Trunk . 343 
 
 147. Lateral View of the Muscles of the Trunk of the Body . . 347 
 
 148. External Parts concerned in Inguinal and Femoral Hernia . . 351 
 
 149. Deep-seated Parts concerned in Inguinal and Femoral Hernia . . 353 
 
 150. Abdominal Muscles and the Abdominal or Inguinal Canal . . 354 
 
 151. Arteries in the Groin of the Left Side . . . . .359 
 
 152. Regions of the Abdomen . . . . . .361 
 
 153. Viscera of the Chest and Abdomen, in situ .... 367 
 
 154. Viscera of the Chest and Abdomen . . . . .369 
 
 155. Viscera of the Upper Part of the Abdomen, with the Coeliac Artery . 377 
 
 156. Superior Mesenteric Artery and its Branches .... 380 
 
 157. The Portal System . . . . . . .382 
 
 158. Inferior Mesenteric Artery and its Branches .... 384 
 
 159. Abdominal Aorta with its Branches . . . . 386 
 
 160. Outline of Stomach . 387 
 
LIST OF ILLUSTRATIONS. XXI 
 
 FIG. PAGE 
 
 161. Front View of the Stomach, with Peritoneal Coat turned off . . 389 
 
 162. Vertical and Longitudinal Section of the Stomach and Duodenum . 390 
 
 163. Cells of the Mucous Membrane of the Human Stomach . . 391 
 
 164. Muscular Coat of the Ileum . . . . . .392 
 
 165. A solitary Gland of the Small Intestine . . . . 394 
 
 166. Patch of Peyers Glands . . . . . . .395 
 
 167. Position and Curvatures of the Large Intestine .... 396 
 
 168. The Cgecum, dried and laid open . . . . .397 
 
 169. Concave Surface of the Liver, showing its Lobes . . . 399 
 
 170. Portal Canal and Portal Vein, with Hepatic Artery and Duct . . 400 
 
 171. Longitudinal Section of an Hepatic Vein . . . 401 
 
 172. The Three Coats of the Gall-Bladder . . . . .403 
 
 173. The Duodenum, Pancreas, and Spleen . . . . . . 404 
 
 174. Right Kidney and its Supra-Renal Capsule .... 407 
 
 175. A Section of the Kidney, surmounted by the Supra-Renal Capsule . 408 
 
 176. Plan of the Renal Circulation . . . . . -409 
 
 177. Urinary Organs, in sitft . ... . . . . 411 
 
 178. Lumbar and Sacral Plexuses . . . . . . 414 
 
 179. Abdominal side of the Diaphragm ..... 418 
 
 180. Bladder and Urethra of a Man, laid open .... 423 
 
 181. Longitudinal Section of the Bladder, Prostate Gland, and Penis . 426 
 
 182. The Glans Penis ........ 427 
 
 183. A Section of the Corpora Cavernosa and Corpus Spongiosum . . 428 
 
 184. Transverse Section of the Testicle ..... 432 
 
 185. Minute Structure of the Testis . . . . , .433 
 
 186. Posterior Aspect of the Male Bladder, showing its Muscular Coat . 434 
 
 187. Side View of the Viscera of the Male Pelvis, in sitft . . . 436 
 
 188. Antero-posterior Section of the Pelvis of a Male . . . 438 
 
 189. Diagram of the Iliac Arteries and their Branches . . . 440 
 
 190. Arteries of the Pelvis and Thigh . . . , .442 
 
 191. Lumbar Plexus and its Branches ..... 448 
 
 192. A diagram of the Formation and Branches of the Sacral Plexus . 450 
 19:;. Muscles of the Perineum of the Male ..... 458 
 
 194. Superficial and Deep Arteries of the Perineum .... 459 
 
 195. The Perineum, after the removal of the Skin and a portion of the 
 
 Superficial Perineal Fascia . . . . . .461 
 
 196. Structures contained between the two Layers of the Deep Perineal 
 
 Fascia ......... 463 
 
 197. A deep Dissection of the Perineum . - . . . 465 
 
 198. Side View of the Viscera of the Pelvis, showing the distribution of the 
 
 Perineal and Pelvic Fasciae ...... 470 
 
 199. Transverse Vertical Section of the Pelvis, showing the distribution of 
 
 the Pelvic Fascia ....... 471 
 
 200. External Organs of Generation in the Virgin . . . .476 
 
 201. Uterus, Ovaries, Fallopian Tubes, Round Ligaments, Vagina, and 
 Vulva ..... . 479 
 
XX11 LIST OF ILLUSTRATIONS. 
 
 FIG- PAGE 
 
 202. Erectile Structures of the External Organs of Generation in the Female 480 
 
 203. Muscles of the Perineum in the Female ..... 481 
 
 204. Posterior View of the Uterus and its Appendages . . . 484 
 
 205. Vertical Section of the Female Pelvis and Viscera . . .486 
 
 206. Anterior and Inner Aspect of the Thigh, showing the course and 
 
 branches of the Femoral Artery . . . . .490 
 
 207. Plan of the Cutaneous Nerves on the Front of the Thigh . .491 
 
 208. Saphenous Opening in the Fascia Lata, Internal Saphenous Vein, etc. 491 
 
 209. Section of the Structures which pass beneath the Femoral Arch . 496 
 
 210. Transversalis Muscle and Fascia . . . . .498 
 
 211. Muscles of the Anterior Femoral Region .... 502 
 
 212. Anterior Crural Nerve and Branches ..... 503 
 
 213. Front View of the Femoral Artery and Primitive and External Iliacs 506 
 
 214. Deep-seated Muscles on the inside of the Thigh . . .508 
 
 215. Muscles of the Gluteal and Posteripr Femoral Regions . . . 512 
 
 216. Deep-seated Muscles on the Posterior Part of the Hip- Joint . .513 
 
 217. Arteries on the Back of the Buttock, Thigh, and Ham . . 515 
 
 218. Branches of the Sacral Plexus to the Hip and Back of the Thigh . 516 
 
 219. Deep Muscles of the Gluteal Region . . . . .517 
 
 220. Ligaments of the Pelvis and Hip-Joint . . . . .521 
 
 221. Side View of the Ligaments of the Pelvis and Hip-Joint . . 523 
 
 222. Posterior View of the Bodies of three Dorsal Vertebras and their Inter- 
 
 vertebral substance ....... 526 
 
 223. A Lumbar Vertebra and horizontal Section of Intervertebral Substance 527 
 
 224. Vertical Section of two Vertebras and their Intervertebral Substance . 527 
 
 225. Front View of two Lumbar Vertebrae and their Intervertebral Substance 528 
 
 226. Internal View of the Arches of three Vertebrae, showing the Ligamenta 
 
 Sub-flava . "". . . . . .529 
 
 227. Anterior View of the Ligaments connecting the Atlas, the Axis, and 
 
 the Occipital Bone .... .531 
 
 228. Posterior Ligaments of the Occipito-atloid, and Atlanto-axoid Articu- 
 
 lations ......... 531 
 
 229. Upper Part of the Vertebral Canal, with the Occipito-axoid Ligament . 532 
 
 230. Posterior View of the Ligaments connecting the Atlas, the Axis, and 
 
 the Occipital Bone . . . . . . .533 
 
 231. The Atlas, and its Transverse Ligament . . . .534 
 
 232. Posterior View of the Ligaments of the Pelvis . . 536 
 
 233. Section of the Pelvis, showing its Ligaments and Sacro-sciatic Foramina 538 
 
 234. Plan of the Cutaneous Nerves on the Posterior Aspect of the Left Leg 540 
 
 235. Internal Popliteal Nerve and some of its Branches on the Right Leg . 541 
 
 236. Superficial Muscles of the Posterior Aspect of the Leg . . . 545 
 
 237. Internal Popliteal and Posterior Tibial Nerves in the Ham and the 
 
 Back of the Leg . . . . . .546 
 
 238. Arteries in the Popliteal Space of the Right Leg . . . 549 
 
 239. Arteries on the Back of the Right Leg . . . .551 
 
 240. Arteries and Deep-seated Veins on the Back of the Right Leg . . 561 
 
LIST OF ILLUSTRATIONS. XX111 
 
 241. Deep Layer of Muscles of the Posterior Tibial Region of the Left Leg 565 
 
 242. Plan of the Cutaneous Nerves on the forepart of the Leg, and the Dor- 
 
 sum of the Foot . . . . . . .569 
 
 243. Superficial Veins of the Front of the Right Leg . . .570 
 
 244. Muscles of the Anterior Tibial Region and Dorsum of the Foot . 573 
 
 245. Anterior Tibial Artery and its Branches . . . .576 
 
 246. Superficial Arteries on the top of the Foot . . . .578 
 
 247. Deep-seated Arteries on the top of the Foot . . . .578 
 
 248. The Musculo-Cutaneous and the Anterior Tibial Nerve . . 580 
 
 249. First Layer of Muscles in the Sole of the Foot . . . .587 
 
 250. Arteries on the Back of the Leg and the Sole of the Foot . . 589 
 
 251. Deep-seated Branches of the Arteries on the Sole of the Foot . . 589 
 
 252. Termination of the Posterior Tibial Nerve in the Sole of the Foot . 590 
 
 253. Deep-seated Muscles in the Sole of the Foot . . . .592 
 
 254. Third and a Part of the Second Layer of Muscles on the Sole of the 
 
 Foot ......... 592 
 
 255. Dorsal Interossei . . . . . . - 594 
 
 256. Plantar Interossei . . . . . . .594 
 
 257. Anterior View of the Ligaments of the Knee-joint . . . 598 
 
 258. Posterior View of the Ligaments of the Knee-joint . . . 598 
 
 259. Internal Ligaments of the Right Knee-Joint .... 603 
 
 260. Longitudinal Section of the Left Knee-Joint, showing the Reflections of . 
 
 the Synovial Membrane ...... 604 
 
 261. Tibio-fibular, and other Ligaments . . . . .606 
 
 262. Posterior View of the Ligaments of the Ankle-Joint . . .607 
 
 263. Internal View of the Ankle-Joint . . . . .609 
 
 264. External View of the Ankle-Joint . . . . .609 
 
 265. Vertical Section of the Ankle-Joint and Foot of the Right Side . 611 
 
 266. Ligaments of the Sole of the Left Foot . . 612 
 
THE 
 
 PRACTICAL ANATOMIST 
 
 GENERAL REMARKS. 
 
 PEKHAPS no part of the course of study which the medical 
 student is required to pursue is approached with a stronger 
 feeling of reluctance than that of practical anatomy. Nor 
 will the neglect of any part of his course cause him more 
 regret when actively engaged in the duties of his profession. 
 Although it must be admitted that there are some things 
 connected with dissecting which are unpleasant, yet, when 
 the value of the knowledge which can be acquired only in 
 the dissecting-room is considered, these things should not be 
 allowed to have the slightest influence on the conduct of the 
 student. It is only in the dissecting-room that he can have 
 the opportunity of seeing the various organs of the body 
 before their relations to each other have been disturbed, or 
 of catting and separating the different tissues of which they 
 are composed, and by which they are connected together. 
 However clearly they may be presented and accurately 
 described in the lecture-room, it is impossible that he should 
 obtain so correct an idea of them as when he can take them 
 in his own hands and examine them for himself. 
 
 There is, perhaps, just reason to apprehend that, for the 
 want of having had experience in the dissecting-room, many 
 members of our profession are deterred from making post- 
 mortem examinations, which would be of great value to 
 themselves, as well as to medical science. It is hardly to 
 be expected that one who had never dissected, or who had 
 dissected but very little, would feel himself competent to 
 make a satisfactory examination of the internal organs of 
 
 o 
 
26 GENERAL REMARKS. 
 
 a dead body. It may be safely averred that the student who 
 has overcame his feeling of repugnance to dissecting, and 
 acquired a fondness for it, will be much more likely, when 
 he comes to practice, to avail himself of every opportunity 
 which may offer to make a post-mortem examination than 
 one who has not had the advantages which the dissecting- 
 room affords. 
 
 It is scarcely necessary to say that a thorough practical 
 knowledge of anatomy is indispensable to the successful per- 
 formance of surgical operations. No student should have a 
 desire to graduate with the intention of practising medicine 
 without feeling assured that he was qualified to perform, at 
 least, a large portion of all the operations which might be 
 required within the limits of his own practice. To be obliged 
 to send a long distance for some one to operate in a case of 
 strangulated hernia, after having exhausted all the means in 
 his own power to reduce it, might be the indirect cause of 
 the death of his patient, sphacelus of the bowel having taken 
 place in consequence of delaying the operation. But it is not 
 to be inferred that the knowledge of anatomy to be acquired 
 in the dissecting-room is more essential to the practice of 
 surgery than to the practice of medicine. Medical anatomy 
 is in every respect as important as surgical anatomy. 
 
 In regard to the time when a student should commence 
 his dissections, I have no hesitation in saying that the sooner 
 he does it after commencing the study of medicine, the better 
 it will be for him. The time which he spends in reading on 
 anatomy before he has had an opportunity of seeing the 
 parts described is, in a great measure, lost. This, I believe, 
 accords with the experience of nine out of every ten who 
 have pursued this course. The quickest and easiest way to 
 acquire a knowledge of a thing is to see it and handle it. A 
 student will acquire a better knowledge of the abdominal 
 viscera in examining them two hours in the dissecting-room 
 than he could in reading a description of them for a week. 
 And it is hardly necessary to say that names are learned with 
 much greater facility when the things which they designate 
 can be seen and inspected. This is especially true in anat- 
 omy, in which so many things are named from their appear- 
 ance, location, function, &c. 
 
 The two great objects to be attained in the study of prac- 
 tical anatomy are first, to learn to dissect ; and second, to 
 
GENERAL REMARKS. 27 
 
 learn the parts dissected. The first is to be accomplished 
 only by care and practice. Dissecting is not merely cutting. 
 The parts must be exposed in a dissection clearly and with- 
 out mutilation. When the student first begins to dissect, it 
 is generally on some muscle. He should proceed with this 
 just as slowly as shall be necessary to remove all the fascia 
 which covers it, so as to leave the fibres of the muscle 
 clear and distinct. If he commences on the abdomen, he 
 should spend at least two hours or more in removing the 
 skin and fascia from the external oblique muscle. The 
 fascia, which may be raised with the skin in his first dis- 
 section, should be made tense by holding it with the forceps, 
 or with the fingers, whenever it can be done, and the knife 
 carried in the direction of the fibres of the muscles. No 
 fascia should be left behind in the progress of the dissection 
 to obscure the fibres, or to be removed afterwards in detached 
 portions. If he learns to dissect the first muscle right, he 
 will have no difficulty afterwards in dissecting muscles in a 
 manner satisfactory to himself and to his teacher. He should 
 always see that the subject, or part, is placed in a position that 
 will render the fibres of the muscle which he is dissecting 
 tense. When this cannot be effected by position, hooks may 
 be used for the purpose. 
 
 When a part has been dissected, it should never be aban- 
 doned until it has been so thoroughly studied and learned that 
 the student can give an accurate description of it in his own 
 words. It is better that he should not commit to memory 
 the language used in the text-books which he reads, except 
 such words as have a technical meaning. When the student 
 has become familiar with the appearance and relations of 
 parts, his attention should be directed to the practical appli- 
 cation of this knowledge. If he has, for instance, examined 
 the liver in situ, and its relations to contiguous parts, he 
 should then study what would be the effect upon these parts 
 when it had increased to two or three times its natural size ; 
 or, if an abscess should be formed in it, the different ways in 
 which the pus might find an outlet. There is no place where 
 he can so well appreciate these things as in the dissecting- 
 room, with the subject before him. 
 
 As a subject is usually divided between several gentlemen, 
 it is exceedingly desirable that each one should prosecute the 
 dissection of the part assigned to him so as not to prevent 
 
28 GENERAL REMARKS. 
 
 the others from proceeding when they may wish to change 
 its position, or remove the part which they are dissecting. 
 Nor should the dissection of a part, when once commenced, 
 be delayed longer than is absolutely necessary, as it is liable 
 to undergo decomposition, to become mouldy, or so dry and 
 hard that it cannot be properly dissected. No part which is 
 not required to be preserved for study, or for protecting other 
 parts, should be allowed to remain attached to the subject, or 
 to lie on the table after it has been cut off. Nothing contrib- 
 utes more to the comfort of a student, when dissecting, than 
 to have a clean table ; hence he should be particular to see 
 that scraps or fluids do not collect on the table or fall on the 
 floor around it. It is not necessary, perhaps, even to allude 
 to the importance of personal cleanliness in the dissecting- 
 room. Every student should be provided with a gown, or a 
 change of garments, so as to prevent his clothes being soiled. 
 
 To be able to dissect properly and satisfactorily, it is indis- 
 pensably necessary to have good instruments. Whether they 
 cost a little more or a little less should have no influence on 
 the mind of the student when making a purchase, provided 
 they are good. I have repeatedly known students to become 
 disgusted with dissecting for no other reason than their 
 attempting it with poor instruments. But, however good 
 they may be, they will become dull in using them, and re- 
 quire to be sharpened. This should be done as often as 
 may be found necessary, as it is impossible to make a good 
 dissection with a dull instrument. 
 
 It should be recollected that the dissecting-room is a place 
 appropriated to study as well as to dissecting, and that con- 
 sequently it is desirable that quietness should be observed by 
 those who are engaged in it. The importance of this must 
 be apparent to every one who has had any experience in the 
 dissecting-room . 
 
PART I. 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 CHAPTER I. 
 OF THE HEAD. 
 
 SECT. I. OF THE FACE. 
 
 THE FACE is bounded above by the root of the nose, eye- 
 brows, and the zygomata ; laterally, by the ears and mastoid 
 processes ; below, by the base of the lower jaw, and a line 
 drawn from its angle to the apex of the mastoid process on 
 each side. As the face is symmetrical, it will be sufficient 
 to describe one side. The student, however, may attend 
 more especially to the dissection of the muscles on one side, 
 and to the vessels and nerves on the other. It is conve- 
 nient to consider the face as divided into several regions ; as 
 the Parotid, the Masseteric, the Buccal, the Mental, the Labial, 
 the Nasal, the Orbital, and the Malar. The location of each 
 of these divisions is indicated by its name. It is not neces- 
 sary for our present purpose to define their boundaries. 
 
 To dissect the face, the head must be placed in a suitable 
 position, and changed from time to time, as may be found 
 most convenient. The lips and cheeks should be made tense 
 by inserting beneath them tow or cotton, and then stitching 
 the lips together ; the nose and eyelids should also be made 
 tense in the same manner. The integument should be raised 
 from below upwards, and from behind forwards. For this 
 purpose make an incision, commencing at the symphysis of 
 the chin, along the base of the lower jaw to its angle, and 
 thence to the apex of the mastoid process, and from this 
 point extend it upwards in front of the ear to the zygoma, 
 and across above the eyebrow to the root of the nose ; make 
 another incision in the median line from the symphysis of the 
 
 3* 
 
30 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 chin to the termination of the first at the root of the nose. 
 These incisions may be commenced and extended, or other 
 incisions may be made, as shall be required in the process of 
 dissection. As a general rule, no more of the integument 
 should be raised than is necessary to expose the parts to be 
 examined at the time of the dissection. 
 
 Fig. 1. 
 
 A VIEW OP THE EXTERNAL CAROTID ARTERY AND ITS BRANCHES. 1. Left primi- 
 tive carotid artery, seen through a section of the sterno-cleido-mastoid muscle. 2. 
 Internal carotid artery. 3. External carotid artery. 4. Superior thyroid artery. 
 5. A branch to the sterno-cleido mastoideus muscle. 6. Lingual artery. 7. Origin 
 of the facial artery. 8. Sub-mental branch. 9. Branch to the sub-tnaxillary gland. 
 10. Facial artery passing over the jaw. 11. Inferior coronary artery. 12. Superior 
 coronary. 13. Branch to anastomose with the infra-orbital. 14. Branch to the 
 ala nasi. 15. Anastomosis of facial with ophthalmic. 16. Nasal branch of oph- 
 thalmic. 17. Its frontal branch. 18. Branch to the orbicularis palpebrarum mus- 
 cle. 19. Origin of the occipital artery. 20. Point where it passes under the 
 splenius muscle. 21. Posterior auricular artery. 22. Origin of the internal maxil- 
 lary. 23. Temporal artery. 24. Transverse facial. 25. Point, of division of the 
 temporal artery. 26. Anterior temporal artery. 27. Middle temporal artery. 28. 
 Posterior temporal artery. 29. Internal mammary artery. 30. Inferior thyroid 
 artery. 31. Transversalis cervicis artery. 
 
THE FACE. 31 
 
 The PAKOTID and MASSETEKIC regions should be examined 
 first, and at the same time. 
 
 Fig. 2. 
 
 A VIEW OP THE VEINS OP THE HEAD AND NECK. a. Facial vein. 5. Temporal 
 vein. e. Transverse facial vein. d. Posterior auricular vein. e. Internal maxil- 
 lary vein. /. External jugular vein. g. Posterior external jugular, h. Anterior 
 jugular, i. Supra-scapular and posterior scapular, k. Internal jugular. I. Occip- 
 ital vein. m. Subclavian vein. 
 
 As the integument is raised and reflected forwards, the 
 PLATYSMA MYOIDES, Fig. 61 (i 4), will be found traversing the 
 anterior part of these regions. Its fibres are generally pale, 
 and are situated immediately beneath the skin, in which they 
 terminate. Some fasciculi are directed towards the angle of 
 the mouth; they form the risorius, or laughing muscle, of 
 Santorini. 
 
 The PAKOTID FASCIA is quite thick and dense, forms a 
 sheath for the parotid gland, and sends numerous prolonga- 
 tions into it. It is continuous below with the cervical, and 
 in front with the masseteric fascia. The density of this 
 fascia renders inflammation of the parotid gland painful, and 
 retards the approach of pus, when formed in the gland, to 
 the external surface. 
 
32 DISSECTION OF THE HEAD AND NECK. 
 
 The MASSETEEIC FASCIA is much thinner than the parotid. 
 Anteriorly, it is lost in the subcutaneous cellular tissue, and 
 below, in the cervical fascia. When pus is formed beneath 
 this fascia, it has a tendency to pass into the neck. 
 
 There are no vessels of any importance situated between 
 the parotid gland and the skin. Some filaments of the 
 auricularis magnus nerve may be traced upwards between the 
 skin and the gland. 
 
 The borders of the parotid, as now seen, should be loosen- 
 ed up, and their relations carefully observed. 
 
 1. The UPPEE border is situated just below the zygoma. 
 The temporal artery, and branches of the facial and fifth pair 
 of nerves, Fig. 62 (3), emerge from beneath this border to 
 ascend to the side of the cranium ; the temporal vein. Fig. 2, 
 enters the gland at this point. 
 
 2. The ANTEEIOE border extends from the zygoma to the 
 angle of the lower jaw ; it overlaps the masseter, more above 
 than below. Coming from beneath this border will be found 
 the following : 
 
 The TEANSVEESE FACIAL AETEEY is situated about a 
 fourth of an inch below the zygoma. It arises in the sub- 
 stance of the gland, from the temporal or external carotid, 
 and crossing the upper part of the masseter, is distributed to 
 the orbital and buccal regions. 
 
 The DUCT OF STENO, Fig. 3 (2), will be observed just below 
 the artery. It is about the size of a crowquill, and is formed 
 by radicals proceeding from the lobules of the gland. It is 
 about two inches in length, and in direction corresponds very 
 nearly to a line drawn from the meatus of the ear to the centre 
 of the upper lip. Its buccal orifice, which is very small, is 
 opposite to the upper middle molar tooth, and near the centre 
 of the line indicating its direction. It perforates the bucci- 
 nator muscle at the anterior border of the masseter. The 
 position of this duct should be noticed particularly, on account 
 of its liability to be injured from accidents, and in surgical 
 operations. 
 
 The GLANDULA SOCIA PAEOTIDIS consists of a few lobules 
 situated between the zygoma and the parotid duct, with which 
 it communicates by a small duct of its own. It is sometimes 
 wanting. 
 
THE FACE. 33 
 
 The nerves, Fig. 63, consist of the Malar, Buccal, and Max- 
 illary branches of the facial. 
 
 A VIEW OF THE SALIVARY GLANDS IN SITU. 1. The parotid gland in situ, an\l 
 extending from the zygoma above to the angle of the jaw below. 2. The duct of 
 Steno. 3. The submaxillary gland. 4. Its duct. 5. Sublingual gland. 
 
 The MALAK BRANCHES pass upwards and forwards to 
 ramify principally in the orbicularis palpebrarum and corru- 
 gator supercilii muscles, and the eyelids. The filaments 
 which ascend above the orbit form anastomotic connections 
 with the supra-orbital of the fifth pair. 
 
 The BUCCAL BRANCHES cross the masseter muscle close to 
 the duct of Steno. They divide into deep and superficial 
 branches. The superficial can be traced beneath the skin to 
 the upper lip, the nose, and the lower eyelid. They supply 
 filaments to the orbicularis oris, the zygomatici major and 
 minor, the levator labii superioris, and the pyramidalis nasi. 
 The deep branches send filaments mostly to the remaining 
 muscles, and form a plexus, as well as interlace and anasto- 
 mose with the infra-orbital of the fifth pair. They also 
 anastomose with the internal and external nasal branches of 
 the ophthalmic nerve. 
 
 The MAXILLARY BRANCHES pass over the lower part of 
 the masseter, and proceed forwards to the chin. They give 
 filaments to the masseter, the buccinator, the depressor 
 
34 DISSECTION OF THE HEAD AND NECK. 
 
 anguli oris, depressor labii inferior! s, levator labii inferioris, 
 and the platysma myoides. They anastomose and interlace 
 with the mental branches of the inferior dental nerve, form- 
 ing the mental plexus. They also anastomose with the buccal 
 branch of the inferior maxillary nerve. The muscles of the 
 face are supplied principally by the facial, while the skin and 
 mucous membrane derive their supply mainly from the fifth. 
 
 3. The LOWER border of the parotid projects somewhat into 
 the neck, and rests against the posterior belly of the digas- 
 tricus, the stylo-hyoideus, and that reflection of the cervical 
 fascia which is attached to the stylo-maxillary ligament, and 
 forms a septum between the parotid and submaxillary regions. 
 
 Near the angle of the jaw the cervical branches of the facial 
 nerve escape from the gland, to be distributed in the upper 
 part of the neck, while branches of the auricularis magnus, a 
 branch of the cervical plexus, enter it. The temporo-max- 
 illary vein will also be found here, leaving the gland to form 
 the external jugular. The external carotid artery enters it on 
 a plane deeper than the digastric and stylo-hyoid muscles, to 
 divide into the temporal and internal maxillary branches. The 
 internal carotid artery and the internal jugular vein with the 
 eighth and ninth pairs of nerves, are situated behind the gland. 
 
 4. The POSTERIOR border rests against the auditory pro- 
 cess and concha of the ear above, and the mastoid process 
 and stern o-cleido-mastoid muscle below. The posterior au- 
 ricular artery and nerve emerge from beneath this border of 
 the gland to get behind the ear. 
 
 The gland must now be dissected so as to get a view of the 
 vessels and nerves in its substance. 
 
 The main trunk of the facial nerve may be easily found 
 by tracing into the substance of the gland one or more of its 
 branches which have already been described. It enters the 
 gland shortly after leaving the foramen stylo-mastoideum, 
 and, after passing upwards and forwards over the external 
 carotid, divides into two principal branches, the Ternporo- 
 maxillary and the Cervico-maxillary. The former subdivides 
 into the temporal, malar, and buccal; the latter into the max- 
 illary and cervical, Fig. 63. 
 
 The TEMPORO-MAXILLARY division is connected by one 
 or more branches with the temporo-auricular branch of the 
 fifth pair. This last branch passes through the upper part of 
 
THE FACE. 35 
 
 the gland, and is deeper seated than the facial. The facial gives 
 off the following small branches before it enters the gland : 
 
 The posterior auricular, which sends filaments to the poste- 
 rior and superior muscles of the ear, and to the posterior belly 
 of the occipito-frontalis ; the styloid, which is distributed to 
 the stylo-hyoid muscle ; and the digastric, which goes to the 
 digastric muscle, and also anastomoses with the glosso-pha- 
 ryngeal and pneumogastric nerves. The auricularis magnus 
 penetrates the parotid, in which some of its filaments anasto- 
 mose with the facial, while others pass through it to the cheek, 
 and to the skin behind the ear. 
 
 The external carotid artery enters the gland from below, 
 and divides into the internal maxillary and temporal ; it also 
 gives off branches to the gland and to the integument and 
 masseter in front. The veins in the gland correspond to the 
 arteries. 
 
 The gland may now be entirely removed, preserving the 
 branches of the facial nerve so that they may be traced to 
 their destination, and its relations to the deeper seated parts 
 observed. It will be found to fill up several irregularities, 
 and to be in relation with the temporo-m axillary articulation, 
 the glenoid cavity behind the glaserian fissure, the ramus of 
 the inferior maxilla, the styloid and mastoid processes of the 
 temporal bone, the internal pterygoid and stylo-glossus mus- 
 cles. The internal carotid artery generally occupies a sulcus 
 on its internal surface. The removal of this gland is ren- 
 dered difficult from its deep-seated projections. It can be 
 torn out from the depressions which it occupies, when it 
 could not well be dissected out. 
 
 The masseter muscle will be described in connection with 
 the spheno-maxillary region ; and the vessels and nerves 
 behind the parotid with the deep-seated parts of the neck. 
 
 The BUCCAL, MENTAL, LABIAL, and NASAL KEGIONS may 
 now be dissected and examined together. The principal 
 constituents of these regions are the Muscles, Arteries, and 
 Nerves. The Muscles are mostly subcutaneous, and belong 
 to the nose and mouth. The principal Artery is the facial, 
 with its branches. Besides this, small branches are furnished 
 by the temporal, internal maxillary, and ophthalmic. The 
 facial vein is situated on the outside of the facial artery, with 
 which it corresponds in its direction and branches. The 
 nerves are derived from the fifth, and facial or portio dura, 
 
36 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 68(1), of the seventh pair. Tlie branches of the facial have 
 been noticed in the description of the Parotid and Masseteric 
 regions. Those of the fifth pair are the terminal branches 
 of the inferior dental, the buccal, the infra-orbital, and the 
 nasal. The inferior dental comes through the mental fora- 
 men, which is situated just below the second bicuspid tooth ; 
 the buccal enters the buccal region behind the anterior bor- 
 der of the masseter ; the infra-orbital emerges from the infra- 
 orbital foramen in the upper part of the canine fossa ; the 
 nasal comes from the inner can thus of the eye, and from the 
 junction of the lower end of the nasal bone with the cartilage. 
 To dissect these parts, the skin must be reflected forwards 
 to the median line, and upwards as far as the root of the 
 nose and the attached border of the lower eyelid. 
 
 The PLATYSMA MYOIDES is lost in the lower part of the 
 face. The posterior fasciculi which cover the facial artery 
 and the lower portions of the parotid gland and masseter 
 muscle, terminate in the subcutaneous areolar tissue and a 
 fasciculus which turns forwards towards the angle of the 
 mouth, called by Santorini the risorius novus. The middle 
 fasciculi blend with the depressor anguli oris and depressor 
 labii inferioris muscles. The anterior fibres mix with those 
 of the opposite side. 
 
 The superficial fascia may now be removed in detached 
 portions while exposing the muscles, arteries, and nerves. 
 
 The facial artery, Fig. l'(i o), is subcutaneous throughout its 
 whole course, except where it passes beneath the zygomatici 
 major and minor muscles, and can be easily traced. Its 
 branches, consisting of the masseteric, mental, inferior and 
 superior coronary and nasal, are irregular in their origin, 
 and must be looked for as the main trunk is dissected from 
 below upwards. The position of the facial artery where it 
 rests upon the inferior maxilla should be noticed, as pressure 
 applied to it at this point will arrest hemorrhage from it or 
 any of its branches. 
 
 The ORBICULARIS ORIS, Fig. 61 (i 3), is situated in the lips, 
 the principal part of which it forms. It consists of two fas- 
 ciculi, one for each lip. These blend at the angles of the 
 mouth with the buccinators, and other muscles inserted at 
 these points. To dissect this muscle, the lips must be made 
 tense. Its external surface is mixed, more or less, with fat, 
 
THE FACE. 37 
 
 and adheres closely to the skin. The labial glands are placed 
 between its inner surface and the mucous membrane. Its 
 action is to close the mouth, and antagonize the muscles 
 inserted into the lips. 
 
 The DEPEESSOR ANGULI OBIS, or TRIANQULARIS, Fig. 61, 
 arises from a ridge on the outer surface of the inferior max- 
 illa, between the insertion of the masseter and the mental 
 foramen. The fibres converge, pass upwards, and are inserted 
 into the angle of the mouth. It partly overlaps the depres- 
 sor labii inferioris and buccinator muscles, from which it is 
 readily distinguished by the different direction of their fibres. 
 It depresses the angle of the mouth, as its name indicates. 
 
 The DEPRESSOR LABII INFERIORIS, or QUADRATUS MENTI, 
 Fig. 64 (i o), arises from the base of the inferior maxilla, com- 
 mencing near the symphysis of the chin, and extending 
 outwards a short distance beneath the preceding muscle. 
 Its fibres pass upwards and inwards, and are inserted into 
 the orbicularis and skin of the lower lip. It is difficult to 
 make a clean dissection of this muscle, on account of the 
 adipose substance mixed with its fibres. The terminal 
 branches of the inferior dental artery and nerve emerge from 
 the mental foramen under this muscle. By detaching a 
 small portion of the muscle from its origin below the second 
 bicuspid, and raising it up, the foramen will be found and 
 the nerve escaping from it. From this point its branches 
 can be easily traced upwards to the skin and mucous mem- 
 brane of the lip, and upwards and outwards where they 
 interlace with the facial nerve, to form the mental plexus. 
 This nerve is sensor, and supplies, besides the lips, the lower 
 and inner part of the face generally. 
 
 The LEVATOR LABII INFERIORIS, or LEVATOR MENTI, Fig. 
 64 (i i), is situated between the mucous membrane and the last 
 muscle. It arises from the alveolar process opposite the in- 
 cisor teeth; its fibres radiate as they pass downwards and 
 forwards, and are inserted into the integument of the chin. 
 The lower part of it is blended with fat. To expose it, the 
 lip should be everted, and the mucous membrane dissected 
 away. It elevates the lower lip by drawing up the chin. 
 
 The BUCCINATOR, Fig. 64 (s), is a broad, thin muscle, located 
 in the cheek. It has three origins ; the lower one arises from 
 
38 DISSECTION OF THE HEAD AND NECK. 
 
 the external surface of the alveolar process of the inferior 
 maxilla in front of the coronoid process; the upper one from 
 the alveolar process of the superior maxilla, in front of the 
 pterygoid process ; and the middle one from the ptery go-max- 
 illary ligament, which stretches from the pterygoid to the base 
 of the coronoid process, and to which the superior constrictor 
 muscle of the pharynx is also attached. From these different 
 origins its fibres converge and pass forwards to the angle of 
 the mouth to be inserted, the inferior ones into the upper, 
 and the superior ones into the lower lip. This muscle is 
 separated behind from the ramus of the inferior maxilla and 
 masseter, by a mass of fat, also by two of the buccal glands 
 called molar. It is perforated by the duct of Steno. It is 
 crossed transversely by the buccal branches of the facial and 
 fifth pair of nerves. The facial artery and vein pass over it 
 vertically. The buccal glands separate its internal surface 
 from the mucous membrane. It draws the angle of the mouth 
 backwards, and makes the lips tense ; assists in expelling the 
 contents of the mouth, and antagonizes the tongue in keeping 
 the food in the process of mastication between the teeth. 
 
 The ZYGOMATICUS MAJOR, Fig. 61 (is), arises from the 
 malar bone, just above its lower border, passes downwards 
 and inwards, and is inserted into the angle of the mouth. It is 
 generally surrounded by more or less fat, and its upper part 
 is covered by the orbicularis palpebrarum ; it crosses over the 
 facial artery and vein. Its action is to draw the angle of 
 the mouth upwards and backwards, as in smiling. 
 
 The ZYGOMATICUS MINOE, Fig. 61 (12), is often a fasciculus 
 from the orbicularis palpebrarum. When a distinct muscle, 
 it arises from the malar bone, above the last muscle, and is 
 inserted into the upper lip with the levator labii superioris, 
 with which it acts, at the same time drawing the lip outwards. 
 
 The LEVATOR LABII SUPERIORIS, Fig. 61 (a), arises from the 
 anterior border of the floor of the orbit, above the canine 
 fossa, where it is overlapped by the orbicularis palpebrarum. 
 Its fibres converge as they pass downwards to be inserted 
 into the skin of the upper lip, and the orbicularis or is. All 
 the lower part of this muscle is subcutaneous. Its action is 
 indicated by its name. 
 
 The infra-orbital nerve and artery will be found escaping 
 from the infra-orbital foramen, beneath the upper part of this 
 
THE FACE. 39 
 
 muscle. To expose these, cut down through the muscle in 
 the direction of its fibres, upon the foramen, and gently raise 
 the nerve, when its filaments will be seen to radiate upwards 
 to the lower eyelid, inwards to the nose, downwards to the 
 upper lip, and outwards and downwards to the cheek. They 
 intermix and anastomose with the facial to form the infra- 
 orbital plexus. It requires a good deal of care and patience 
 to trace these filaments to their termination. The infra- 
 orbital artery is one of the terminal branches of the internal 
 maxillary. It inosculates with, the facial, transverse facial, 
 and ophthalmic. 
 
 The LEVATOR ANGULI ORIS, or CANINUS, Fig. 64 (e), arises 
 from the canine fossa, below the infra-orbital foramen, and 
 beneath the preceding muscle ; passes downwards, and is 
 inserted into the angle of the mouth. It raises the angle of 
 the mouth, and antagonizes the depressor anguli oris, with 
 which some of its fibres are continuous. 
 
 The LEVATOR LABII SUPERIORIS AL^QUE NASI, Fig. 61 (s), 
 arises from the upper part of the nasal process of the superior 
 maxilla. It passes downwards on the side of the nose, 
 divides into the nasal and labial portions, and is inserted, the 
 former into the ala of the nose, and the latter into the upper 
 lip. Its name indicates its use. 
 
 The COMPRESSOR NASI, or TRIAKGULARIS NASI, Fig. 64 (5), 
 is partly concealed by the preceding muscle. It arises from 
 the inner part of the canine fossa, passes forwards to spread 
 out over the ala of the nose, and is inserted into a thin 
 aponeurosis, common to it and its fellow on the opposite side; 
 it is also connected with the pyramidalis. It compresses the 
 nostril when it acts alone, but may expand it when it acts 
 in conjunction with the pyramidalis. 
 
 The DEPRESSOR LABII SUPERIORIS AL^QUE NASI, or 
 MYRTIFORMIS, Fig. 64 (7), is exposed by everting the upper 
 lip, and dissecting off the mucous membrane on the side of the 
 fraBnum. It arises from the alveolar process of the superior 
 maxilla in front of the incisor teeth, passes upwards and 
 forwards, and is inserted into the upper lip and the fibro- 
 cartilage of the ala and septum of the nose. Its name indi- 
 cates its actions. 
 
 The PYRAMIDALIS NASI, Fig. 64 (3), appears to be a fascicu- 
 lus of the occipito-frontalis prolonged downwards on the nose. 
 
DISSECTION OF THE HEAD AND NECK. 
 
 It is inserted into the aponeurosis of the compressor nasi. It 
 causes the vertical ridge sometimes seen at the root of the 
 nose. The integument of the nose is supplied with nerves 
 from the infra-orbital and the internal and external nasal. 
 The facial artery, after .giving off the branches already 
 enumerated, ascends to the forehead between the eyebrows ; 
 its terminal branch is called the angularis. 
 
 'SECT. II. APPENDAGES OF THE EYE OUTSIDE OF THE OKBIT. 
 
 The dissection of the orbital region will embrace those 
 appendages of the eye which can be exposed and studied 
 without removing any portion of the walls of the orbit. 
 These consist of the orbicularis palpebrarum, corrugator su- 
 percilii, and tensor tarsi muscles ; the eyebrows, eyelashes, 
 tarsal cartilages, Meibomian glands, conjunctiva, caruncula 
 lachrymalis, lachrymal gland and ducts, puncta lachrymalia, 
 lachrymal canals and sac, and nasal duct. 
 
 The integument in this region should be removed by cut- 
 ting in the direction of the fibres of the orbicularis, but in 
 the first place the eyelids should be made tense by inserting 
 beneath them cotton or tow, and then stitching their edges 
 together. 
 
 The EYEBKOW, Fig. 4 (i), on each side, is situated just above 
 
 the attached border of the 
 upper eyelid, and rests on 
 the superciliary ridge of the 
 frontal bone. It is gener- 
 ally arched and covered 
 with hairs, which have a 
 direction from within out- 
 wards. The integument is 
 separated from the orbicu- 
 laris and occipito-frontalis 
 muscles by a thick, dense 
 cellulo-adipose layer. The 
 eyebrows can be moved 
 upwards, downwards, or 
 towards each other. 
 
 Fig. 4. 
 
 A FRONT VIEW OF THE LEFT EYE, MODE- 
 RATELY OPENED. 1 The supercilia. 2. The 
 cilia of each eyelid. 3. The inferior palpe- 
 bra. 4. The internal canthus. 5. The ex- 
 ternal canthus. 6. The caruncula lachry- 
 malis. 7. The plica semilunaris. 8. The 
 eyeball. 9. The pupil. 
 
 The EYELASHES, Fig. 
 4 (2), consist of three or 
 four rows of curved hairs, growing from the free borders of 
 
APPENDAGES OF .EYE OUTSIDE OF ORBIT. 41 
 
 % 
 
 the eyelids. In the upper eyelid they are curved upwards, 
 in the lower, downwards ; they are longer in the centre than 
 at the extremities of the eyelids. Their bulbs are situated 
 between the orbicularis and the tarsal cartilages. 
 
 The ORBICULARIS PALPEBRARUM, Fig. 61 (7), entirely 
 surrounds the fissure between the eyelids. It is divided 
 into three portions, viz : the orbicular, the palpebral, and 
 the ciliary. The orbicular is spread out around the base of 
 the orbit, and rests, above, on the superciliary ridge and 
 corrugator supercilii muscle; on the outside, on the tem- 
 poral aponeurosis, and below, on the malar bone and zygo- 
 maticus major and levator labii superioris muscles; its fibres 
 are red and well marked. The palpebral and ciliary portions 
 consist of a thin layer of pale fibres situated in the eyelids ; 
 the latter lies next to their free borders, and is somewha't 
 thicker than the former. This muscle arises from the inter- 
 nal angular process of the frontal bone, the nasal process of 
 the superior maxilla, and from the upper and lower border 
 of the tendo-palpebrarum ; from this narrow attachment the 
 fibres proceed outwards, so as to embrace the base of the 
 orbit and the fissure between the eyelids. It closes the eye- 
 lids, as in winking, principally by depressing the upper 
 one ; this is done by the palpebral and ciliary fibres, which 
 are involuntary in their action. It also presses the eyelids 
 against the ball of the eye, and directs the tears towards the 
 puncta lachrymalia. As its principal attachment is at the 
 inner canthus of the eye, it draws the integument in that 
 direction, and that above the orbit more than that below. 
 It is separated in the eyelids from the skin by loose areolar 
 tissue, which is very liable to serous infiltration. 
 
 The TENDO-PALPEBRARUM, or LIGAMENTUM PALPEBRA- 
 RUM, arises from the nasal process of the superior maxilla in 
 front of the lachrymal groove, passes outwards and back- 
 wards to the inner angle of the eyelids, where it divides 
 into two parts, one to be attached to the upper, and the other 
 to the lower tarsal cartilage. It is about two lines and a 
 half in length, and crosses the lachrymal sac a little above its 
 centre ; its broadest diameter is at first vertical and then 
 horizontal ; from its upper and lower borders a fibrous lamina 
 is reflected over the lachrymal sac, and is attached to the 
 osseous margin which surrounds it. When the orbicularis 
 
 4* 
 
42 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 5. 
 
 contracts, this tendon can be felt in the living subject. In 
 opening the lachrymal sac, the incision should be made below 
 the tendon, to avoid injuring it. 
 
 The CORRUGATOR SuFERCiLii, Fig. 64 (2), is exposed by 
 reflecting downwards the upper portion of the orbicularis. 
 It arises from the inner part of the superciliary ridge, passes 
 upwards and outwards, and is inserted into the orbicularis, 
 near the junction of its middle and outer thirds. The super- 
 cilii muscles depress and approximate the eyebrows, pro- 
 ducing the vertical wrinkles on the forehead. The expression 
 of frowning depends on the action of these muscles. 
 
 The TENSOR TARSI, or THE MUSCLE OF HORNER, Fig. 5, 
 arises from the upper part of the os unguis just behind the 
 lachrymal groove ; it is about three lines in breadth and 
 six in length, and is situated behind the tendo-palpebrarum. 
 
 It divides into two slips, 
 which are inserted, one into 
 the upper lachrymal duct, 
 and the other into the lower. 
 To expose this muscle the 
 eyelids should be detached, 
 except at the inner can- 
 thus, and reflected over the 
 nose ; its fibres will then be 
 distinctly seen by the re- 
 moval of a portion of the 
 conjunctiva and areolar tis- 
 sue between the eyeball and 
 the lachrymal bone. Its 
 action is to govern the po- 
 sition of the puncta lachry- 
 malia, so as to facilitate the entrance of the tears, and to 
 keep the eyelids applied to the eyeball ; it may also com- 
 press the lachrymal sac if distended. 1 
 
 The MEIBOMIAN GLANDS, Fig. 6 (e), consist of a series of 
 tubes, more or less tortuous, situated in grooves on the pos- 
 terior surface of the tarsal cartilages. In length they cor- 
 
 1 A small muscle, situated in the outer part of the orbit, and connected to 
 the tarsal cartilages, is described by Dr. N. R. Mosely, of Philadelphia, in 
 the Boston Medical and Surgical Journal, August 3, 1853. Dr. Mosely regards 
 it as an antagonistic muscle of the tensor tarsi of Horner. 
 
 A VIEW OP THE TENSOR. TAKSI MUS- 
 CLE. 1, 1. Bony margins of the orbit. 
 2. Opening between the eyelids. 3. In- 
 ternal face of the orbit. 4. Origin of the 
 tensor tarsi. 5, 5. Insertion in the neigh- 
 borhood of the puncta lachrymalis. 
 
APPENDAGES OF EYE OUTSIDE OF ORBIT. 43 
 
 respond to the breadth of the cartilages. There are between 
 thirty and forty in the upper lid, and about twenty in the 
 lower. Each tube has opening into it on each side several 
 small pouches or follicles. Their external orifices may be 
 seen on the posterior edge of the free border of each lid, 
 and from which a waxy secretion may be pressed ; this se- 
 cretion prevents the tears from flowing over the lids. 
 
 Fig. 6. 
 
 MEIBOMIAN GLANDS, SEEN FROM THE INNER OR OCULAR SURFACE OF THE EYE- 
 LIDS, WITH THE LACHRYMAL GLAND THE LEFT SIDE. a. Palpebral conjunctiva. 
 1. Lachrymal gland. 2. Openings of lachrymal ducts. 3. Lachrymal puncta. 
 6. Meiboniian glands. 
 
 The TAESAL CARTILAGES, with their fibrous attachments, 
 form the framework of the eyelids. They consist of two 
 fibro -cartilaginous plates, one for each lid. Each one pre- 
 sents two surfaces and two borders. The external surface 
 of each is convex, and separated from the ciliary fibres of 
 the orbicularis palpebrarum by a thin layer of areolar tissue ; 
 the internal surface is concave, and grooved for the Mei- 
 bomian glands, and separated from the conjunctiva by areolar 
 tissue also. The free borders are thick, and form the free 
 edges of the eyelids ; they are nearly horizontal when the 
 lids are closed, and slightly beveled from before backwards, 
 so as to form, when they are in apposition^ a canal for the 
 passage of the tears from the outer to the inner part of the 
 eyeball. The lower one is merely a narrow band, about a 
 line and a half in breadth. The upper one is nearly half an 
 inch broad at its centre, but diminishes in breadth towards 
 
44 DISSECTION OF THE HEAD AND NECK. 
 
 its extremities. Each, one is attached to the margin of the 
 orbit by a fibrous lamina, which is continuous with the pe- 
 riosteum. This fibrous layer, sometimes called the palpebral 
 or broad tar sal ligament, is thin at the inner part of the 
 orbit, but quite thick and dense at the outer part. Besides 
 the fibrous layer from the margin of the orbit, the tarsal 
 cartilage of the upper lid has inserted into it the tendon of 
 the levator palpebrae superioris muscle. The internal extre- 
 mities of the tarsal cartilages are fixed by the tendo-palpe- 
 brarum. 
 
 The CARUNCULA LACHEYMALIS, Fig. 4 (e), is a small red 
 body situated at the inner angle of the eyelids, and in the 
 centre of the locus lachrymalis. It is composed of sebaceous 
 follicles resembling the Meibomian glands. It secretes a 
 whitish substance, which is often seen at the inner canthus. 
 It is covered by a fold of the conjunctiva, which is per- 
 forated by the external orifices of the follicles ; several hairs 
 usually project from it. It varies in color, as in health and 
 in sickness. 
 
 The CONJUNCTIVA is divided into an ocular and a palpebral 
 portion. The former covers the anterior third of the eye- 
 ball, with which it is loosely connected around its circum- 
 ference, but becomes more closely adherent as it approaches 
 the margin of the cornea. That it extends over the cornea 
 can be very satisfactorily demonstrated. It is, however, so 
 modified in its structure as to become perfectly transparent, 
 and so intimately blended with the cornea, that it cannot be 
 easily dissected off', especially from the centre of it. The 
 latter, or palpebral portion, lines the internal surfaces of the 
 lids, and is continuous over their free margins with the skin. 
 It is closely connected to the posterior surfaces of the tarsal 
 cartilages, where it covers the Meibomian glands, and is very 
 vascular. 
 
 The palpebral sinuses are formed by the reflection of the 
 conjunctiva from the globe of the eye to the lids. In these 
 sinuses, or culs-de-sac, it is very loosely connected to the 
 areolar tissue beneath. At the inner canthus the conjunc- 
 tiva forms a fold, called the plica semilunaris. This is just 
 outside the caruncula, and disappears when the globe is 
 turned outwards ; it may be regarded as the rudiment of 
 
APPENDAGES OF EYE OUTSIDE OF OKBIT. 45 
 
 the membrana nictitans or the third eyelid in birds. The 
 conjunctiva is perforated by the lachrymal dncts in the 
 outer part of the superior palpebral sinus ; by the Meibomian 
 glands, along the inner edge of the lids; by the sebaceous 
 follicles in the caruncula lachrymalis ; and by the puncta 
 lachrymalia near the inner extremities of the eyelids. 
 
 The LACHRYMAL GLAND, Fig. 6(1), may now be exposed in 
 the upper and outer part of the orbit. It should be studied 
 from without and also from within the orbit. In structure it 
 resembles the salivary glands. It consists of two lobes, an 
 orbital and a palpebral. The former is about half an inch 
 in breadth, and nearly three-fourths of an inch in length ; its 
 orbital surface is convex, and occupies the lachrymal fossa 
 on the inner side of the external angular process of the 
 frontal bone; its ocular surface is concave, and in apposition 
 with the globe of the eye. The latter or palpebral lobe is 
 prolonged into the upper lid as far as the attached border of 
 the tarsal cartilage ; its under surface is covered by the con- 
 junctiva, through which it can be seen when the lid is 
 everted. The two lobes are separated from each other 
 merely by fascia. The tears secreted by the lachrymal 
 gland are poured upon the conjunctiva through from six to 
 ten ducts ; these are arranged in a line, and open on the 
 inner surface of the upper lid. They may be detected bj 
 the application of a colored liquid, which will be absorbed 
 into their mouths. 
 
 The PUNCTA LACHEYMALIA, Fig. 6 (s), are two orifices, one 
 in the free border of each eyelid at the inner extremity of the 
 tarsal cartilage. They may be distinctly seen in the centre 
 of two small eminences called the lachrymal papillce. They 
 look somewhat backwards towards the eyeball, in which posi- 
 tion they are kept by the tensor tarsi muscle. A bristle can 
 be readily introduced into them, and through them into the 
 ducts which lead into the lachrymal sac. 
 
 The LACHRYMAL CANALS, or CANALICULI LACHRYMALES, 
 Fig. 7, e, extend from the puncta to the lachrymal sac. Their 
 parietes are of a dense fibrous structure, which keeps them 
 constantly open for the passage of the tears. The inferior 
 one is the shortest ; it at first descends, then turns inwards 
 and upwards to enter the upper and outer part of the sac. 
 The superior one is at first directed upwards, then inwards 
 
46 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 and downwards, and enters the sac near the other, behind the 
 tendon of the orbicularis. 
 
 The LACHRYMAL SAC occupies a fossa formed by the su- 
 perior maxilla and os unguis in the inner and anterior part 
 of the orbit. It is continuous with the upper extremity of 
 the ductus ad nasum, from which it is separated only by a 
 constriction or fold of the mucous membrane. It is separated 
 from the anterior extremity of the middle meatus of the nose 
 by the lachrymal bone. 
 
 The DUCTUS AD NASUM, Fig. 7, /, leads from the lachrymal 
 sac into the anterior extremity .of the inferior meatus of the 
 
 Fig. 7. 
 
 LACHRYMAL APPARATUS AND NASAL DUCT. a, b, c. Lachrymal gland and its 
 appendage, d. Puncta lachryinalia. e. Lachrymal canals, f. Nasal duct laid 
 open. g. Insertion of tendon of superior oblique muscle after being reflected, h. 
 Supra-orbital foramen; the artery, vein, and nerve have been cut across, i. Inte- 
 rior of nasal duct near its termination in nostril. 
 
 nose. It is directed downwards, backwards, and outwards ; 
 its osseous walls are composed of the superior maxilla, os 
 unguis, and inferior turbinated bone. At is lower orifice there 
 is a fold of mucous membrane which may serve as a valve. 
 Its length is about three-fourths of an inch. Through the 
 
SOFT PAKTS ON THE UPPER PART OF CRANIUM. 47 
 
 lachrymal ducts, lachrymal sac, and nasal duct, the conjunc- 
 tiva is continuous with the lining membrane- of the nasal 
 fossa; and as the former is prolonged into the lachrymal gland 
 through its excretory ducts, there is a direct sympathetic 
 connection established between that gland and the mucous 
 membrane of the nose. 
 
 The appendages of the eye, which have just been described, 
 deserve the careful attention of the student. They are fre- 
 quently the seat of diseases which require surgical operations. 
 A minute examination of the structure of the eyelids, and the 
 lachrymal passages especially, is important. 
 
 SECT. III. DISSECTION OF THE SOFT PARTS ON THE UPPER 
 
 PART OF THE CRANIUM. 
 
 This region is included within the circumference of a line 
 commencing just above the root of the nose, and extending 
 round the head through the eyebrows, along the zygomatic 
 arches, and just above the ears back to the occipital protuber- 
 ance. It is subdivided into the Frontal, Temporal, Auricular, 
 and Occipital regions, The parts to be studied in this dissec- 
 tion are: the integuments, the cellule-adipose layer, the tem- 
 poral fascia, the occipito-frontal muscle, the upper part of the 
 orbicularis palpebrarum, the temporal muscle above the zygo- 
 matic arch, the attollens aurem, the attrahens aurem, the retra- 
 hens aurem, the cranial branches of the occipital, temporal, 
 auricular, supra- orbital and facial arteries, and their corres- 
 ponding veins, the cranial branches of the occipital, facial, and 
 trifacial nerves, and the pericranium. 
 
 In removing the skin, an incision should be made from the 
 root of the nose along the median line to the occipital pro- 
 tuberance, and another at right angles to this, extending down 
 to the ear. The skin should then be dissected off in two flaps. 
 The different layers which cover the cranium should be dis- 
 sected on one side, and the nerves and vessels on the other. 
 The integument which is covered with hair adheres closely to 
 the cellulo-adipose layer, and some care is requisite to separ- 
 ate them. 
 
 The CELLULO-ADIPOSE LAYER is the thickest and most 
 dense on the upper and posterior part of the head. Numerous 
 
48 DISSECTION OF THE HEAD AND NECK. 
 
 adipose cells are interspersed through it. The compactness 
 of this structure, with its high degree of vitality, is said to be 
 the cause of the tendency of the scalp to take on erysipelatous 
 inflammation after injuries. When arteries are divided in its 
 substance, the forceps instead of the tenaculum should be 
 used in ligating them. 
 
 The OCCIPITO-FRONTAL MUSCLE, Fig. 61 (i, 2, s), with its 
 broad aponeurosis, extends from the root of the nose and the 
 superciliary ridge to the superior transverse ridge of the 
 occiput. It consists of two fleshy bellies connected by a broad 
 aponeurosis, which expands over the arch of the cranium. 
 
 The OCCIPITAL PORTION arises from the superior transverse 
 ridge of the occipital bone, and from the adjacent portion of 
 the mastoid process of the temporal bone. The fibres pass 
 upwards and somewhat inwards, and terminate in the tendon. 
 
 The FEONTAL POETION is blended with the pyramidalis 
 nasi, the orbicularis palpebrarum, and the integument ; some 
 of its fibres are also attached to the internal angular process 
 of the frontal bone. It joins the tendon nearly opposite the 
 coronal suture. Its fibres are generally paler than those of 
 the occipital portion. The tendon of this muscle is continu- 
 ous across the median line with that of the opposite side ; and 
 from its outer border, the superficial temporal fascia extends 
 downwards over the deep temporal fascia or aponeurosis. 
 The use of this muscle is to move the scalp, to raise the eye- 
 brows, and, in some measure, the upper eyelids. It adheres 
 closely to the scalp, while it glides freely on the parts beneath 
 it. It causes the transverse wrinkles on the forehead. 
 
 The ATTOLLENS AUREM, Fig. 61 (4), is situated in the tem- 
 poral region above the ear. It arises broad from the aponeu- 
 rosis of the occipito -frontal muscle ; its fibres converge as they 
 descend, and are inserted into the concha of the ear. Its use 
 is to raise the ear, and to render tense the aponeurosis from 
 which it arises. 
 
 The ATTRAHENS AUREM, Fig. 61 (3), is situated immediately 
 in front of the preceding muscle. It arises from the aponeu- 
 rosis of the occipito -frontal muscle and the zygoma, and is 
 inserted into the anterior part of the helix. It draws the ear 
 upwards and forwards. 
 
SOFT PAETS ON THE UPPER PART OF CRANIUM. 49 
 
 The EETRAHENS AUREM, Fig. 61 (e), is placed behind the ear. 
 It generally consists of two or three fasciculi. It arises from 
 the mastoid process, and is inserted into the posterior and lower 
 part of the concha. It draws the ear backwards and enlarges 
 the meatus. Having dissected the occipito-frontal muscle and 
 the muscles of the ear, they should be removed. Beneath 
 the occipito-frontal muscle, more or less loose areolar tissue 
 will be observed, which facilitates the movements of that 
 muscle on the pericranium. The pericranium is the external 
 periosteum of the bones which it covers. It can be readily 
 separated from the bone except along the sutures. 
 
 The student should now carefully study the different layers 
 which have just been examined with reference to wounds 
 involving one or more of them, and especially in view of 
 collections of pus between the different layers, or beneath the 
 pericranium. 
 
 The TEMPORAL APONEUROSIS occupies the whole of 
 the temporal region. It arises from the temporal ridge 
 above, and is attached below to the zygomatic arch. The 
 lower part of it is divided into two layers, one of which is 
 inserted into the outer, and the other into the inner border 
 of the arch, thus leaving a triangular space between them, 
 which is filled with adipose substance, and traversed by the 
 middle temporal artery, and a small branch of the superior 
 maxillary nerve. The temporal muscle arises partly from 
 the under surface of this aponeurosis. It will be observed, 
 that if pus should collect beneath the temporal aponeurosis, 
 it would naturally seek an outlet beneath the zygomatic 
 arch ; or, if it should collect between the two layers above 
 the zygoma, it would necessarily be confined to that space. 
 
 The TEMPORAL MUSCLE, Fig. 64 (i), lies beneath the tem- 
 poral aponeurosis. It arises from the whole of the temporal 
 fossa and ridge, from the inner surface of the aponeurosis 
 and from the zygomatic arch. Its fibres converge, and 
 passing downwards beneath the zygoma, are inserted by 
 a strong tendon into the coronoid process of the inferior 
 maxilla. The muscle increases in thickness as it descends. 
 When the entire muscle acts, it raises the lower jaw; the 
 posterior fibres can move it backwards, while the anterior 
 fibres can draw it forwards. This muscle may also assist in 
 producing a rotary movement of the jaw. 
 
50 DISSECTION OF THE HEAD AND NECK. 
 
 It will be seen that the temporal aponeurosis and muscle, 
 by their strength and thickness, serve greatly to protect that 
 portion of the parietes of the cranium which they cover, and 
 which in this region are very thin. 
 
 The vessels and nerves may now be dissected on the oppo- 
 site side; and for this purpose, the integument should be 
 raised in the same manner as for the dissection of the muscles 
 and fascia3. 
 
 The temporal and occipital, Fig. 1 (23, 20), are the principal 
 arteries. Besides these, there are the terminal branches of the 
 facial, the supra-orbital, and the posterior auricular. The 
 nerves, Fig. 63, are derived from the fifth, the facial, and the 
 cervical. To dissect the vessels and nerves, they should be 
 traced from below upwards. 
 
 Entering the frontal region from below will be found the 
 terminal branch of the facial artery, and the supra-orbital, 
 and near these the supra-orbital and frontal nerves. 
 
 The SUPRA-ORBITAL ARTERY and NERVE pass through 
 the supra-orbital foramen. The artery is distributed to 
 the muscles and integument of this region. The nerve 
 ascends beneath the orbicularis palpebrarum and occipito- 
 frontal muscles, and some distance above the orbit divides 
 into two cutaneous branches, which perforate the latter 
 muscle, and ascend in long slender filaments to the top of 
 the head. In its course it gives branches to the muscles 
 beneath which it passes, and through which filaments are 
 sent to the skin which covers the muscles. 
 
 The terminal branch of the FACIAL ARTERY supplies the 
 parts above the root of the nose. 
 
 The FRONTAL NERVE is placed on the inner side of the 
 supra-orbital, and has a similar course and distribution. 
 
 Besides the supra-orbital, the OPHTHALMIC ARTERY usually 
 sends one or more small branches to the forehead. 
 
 The TEMPORAL ARTERY passes upwards over the zygoma, 
 and close to the ear. It is accompanied by the auriculo- 
 temporal branch of the inferior maxillary division of the 
 fifth pair of nerves. It divides into an anterior and a poste- 
 rior branch. Just above the zygoma it gives off the middle 
 temporal branch, which perforates the temporal aponeurosis. 
 
SOFT PARTS ON THE UPPER PART OF CRANIUM. 51 
 
 The anterior division pursues a tortuous course upwards and 
 forwards to the upper part of the forehead. The posterior 
 division passes upwards and backwards to the upper and 
 back part of the head. The lower part of this artery should 
 never be opened for the abstraction of blood, on account of its 
 depth and the danger of ecchymosis occurring. The anterior 
 division is superficial, and easily found on the forehead. 
 
 The NERVES in this region are a small branch of the 
 superior maxillary, the auricula-temporal branch of the infe- 
 rior maxillary, and branches of the facial nerve. 
 
 The first one perforates the temporal aponeurosis just above 
 the zygoma. The auriculo-temporal divides into branches, 
 which ascend to the top of the head. It also sends filaments 
 to the upper part of the ear, to the retrahens aurem, and to 
 the integument above the ear. The branches of the facial 
 nerve pass up over the zygoma, and ramify in the temporal 
 and frontal regions, anastomosing with the branches of the 
 fifth pair. 
 
 The POSTERIOR AURICULAR ARTERY, Fig. 1 (21), ascends 
 between the mastoid process and the ear. It sends branches 
 to the ear, to the integument behind the ear, and to the occipito- 
 frontal muscle and the retrahens aurem. The posterior auricu- 
 lar branch of the facial nerve, and the deep auricular branch 
 of the auricularis magnus, are found in this region. 
 The former passes upwards over the anterior and outer sur- 
 face of the mastoid process, and divides into an ascending 
 and a horizontal branch. The ascending branch supplies the 
 retrahens aurem, and the attollens aurem; the horizontal 
 branch is distributed to the occipito-frontal muscle; The 
 latter ascends at first in front of the mastoid process, and 
 then behind the retrahens aurem. It divides into an anterior 
 and a posterior branch, which are distributed to the skin. 
 
 The OCCIPITAL ARTERY becomes superficial at the inner 
 border of the splenius muscle. It then ascends on the back 
 part of the head, ramifying in the scalp, and anastomosing 
 with the posterior auricular, the temporal, and the corres- 
 ponding one on the opposite side. 
 
 The NERVES in this region are the Ocdpitalis Major and 
 the Ocdpitalis Minor. The former perforates the trapezius 
 muscle, and accompanies the occipital artery. The latter 
 ascends on the inner border of the mastoid muscle, and rami- 
 
52 DISSECTION OF THE HEAD AND NECK. 
 
 fies on the back of the head, between the auricular and the 
 great occipital nerves. 
 
 The SUPEKFICIAL VEINS, Fig. 62, of the head correspond 
 generally to the arteries. Those which pass through the 
 foramina in the parietal bones are named the emissaries of 
 Santorini. They open into the superior longitudinal sinus. 
 
 SECT. IV. DISSECTION OF THE MEMBRANES OF THE BRAIN. 
 
 Having dissected the soft parts covering the upper part of 
 the cranium, the calvaria may be removed. If it be de- 
 sired to preserve the cranium for a preparation, this should 
 be done with a saw. The incision should pass through the 
 occipital protuberance behind, about half an inch above the 
 ear on each side, and just above the superciliary ridges in 
 front. The variations in the thickness of the skull at differ- 
 ent points through which this incision would pass, should be 
 observed on one which has already been sawed. It is better 
 to divide both tables entirely with the saw, so that but little 
 effort will be required afterwards to raise the calvaria from 
 the dura mater. This may be done with a chisel, first prying 
 up one part and then another, until it has been detached 
 around the whole circumference of the incision. If the saw 
 be sharp, there will be but little danger of injuring the brain 
 or its membranes, as there will then be no necessity for 
 using any force to press it down on the bone. The position of 
 the subject should be changed to saw through the anterior 
 and posterior portions of the cranium. 
 
 The strength of the adhesions between the upper part of 
 the cranium and the dura mater, varies greatly in different 
 subjects. Sometimes a good deal of force is required to 
 effect a separation, although the bone has been entirely di- 
 vided. 
 
 The description of the meninges of the brain will be divided 
 into two parts. The first will embrace all the parts which 
 can be examined before the removal of the brain ; the second 
 will include the deep parts, or those which can be seen only 
 after the brain has been removed. 
 
 The membranes of the brain consist of the Dura Mater, 
 the Arachnoid, and the Pia Mater. 
 
OF THE MEMBRANES OF THE BRAIN. 53 
 
 The DURA MATER is a fibro-serous membrane. It adheres 
 to the inner surface of the osseous walls of the cranium. It 
 is of a dense fibrous structure. Its fibres run in different 
 directions, thus imparting to it great strength. In some 
 places it separates into two layers, as in the formation of 
 sinuses for the transmission of venous blood. The firmness 
 of its attachment at different points to the cranium, prevents 
 any general displacement of it taking place. Its external 
 surface is rough, while its internal surface is smooth, and 
 presents the appearance of serous membranes generally. 
 Its uses are the following : 
 
 1. It performs the office of an internal periosteum to the 
 bones of the cranium. 2. It furnishes processes to separate 
 and support different parts of the encephalon. 3. It sup- 
 plies canals or sinuses for conveying venous blood. 4. It 
 provides the nerves with fibrous sheaths as they pass through 
 the foramina in the base of the cranium. 5. It affords a 
 general protection to the brain, especially in early life, before 
 the bones of the cranium are yet completely ossified. Its 
 intimate connection with the external periosteum will be 
 noticed at another time. 
 
 The ARACHNOID TUNIC is a serous membrane, and, like 
 other serous membranes, forms a shut sac; the reflected 
 portion of it, however, is described as a part of the dura 
 mater. This membrane, the visceral portion, surrounds every 
 part of the encephalon. It adheres quite closely to the pia 
 mater, especially immediately over the convolutions, except 
 at particular parts on the under surface of the brain. It 
 is connected to the reflected portion by an arrangement 
 consisting of tubes which allows the vessels and nerves to 
 pass to and from the brain without interrupting its continuity. 
 The ends of each one of these tubes are continuous, the one 
 with the reflected portion, and the other with the visceral 
 portion. 
 
 The PIA MATER is a vascular membrane. It invests every 
 part of the exterior of the encephalon, dips in between the 
 convolutions, and also lines the ventricles. It is intimately 
 connected with the substance of the brain by vessels and 
 prolongations of areolar tissue. 
 
 With these general remarks on the meninges of the brain, 
 the student will be prepared to commence the examination 
 
 5* 
 
54 DISSECTION OF THE HEAD AND NECK. 
 
 of them in situ, and as they will appear from time to time in 
 the progress of his dissection. 
 
 On the inner surface of the calvaria will be observed a 
 groove extending along the median line ; this corresponds to 
 the superior longitudinal sinus. On each side sure furrows 
 which present in their arrangement an arborescent appear- 
 ance; these are occupied by branches of the middle meningeal 
 artery. Small depressions on either side of the median line 
 are commonly seen ; these are for the lodgement of the exter- 
 nal glands of Pacchioni. 
 
 On the external surface of the dura mater, the situation of 
 the superior longitudinal sinus, the ramifications of the middle 
 meningeal artery, and the external glands of Pacchioni, will 
 be noticed. The dura mater is usually studded with points 
 of blood caused by the rupture of vessels in the removal of 
 the calvaria. 
 
 The SUPERIOR LONGITUDINAL SINUS, Fig. 8, J, may now 
 be laid open, and any coagulated blood which it may contain, 
 
 Fig. 8. 
 
 A VIEW OP THE SINUSES OP THE DURA MATER. a. The torcular Herophili. 6. 
 The superior longitudinal sinus, c. The inferior longitudinal sinus, d. The straight 
 sinus, e. The venae Galeni. f. The lateral sinus of the left side. g. The posterior 
 occipital sinus, h. The superior petrosal sinus, i. The inferior petrosal sinus, k. 
 The internal nasal veins. 
 
 washed out. It commences at the foramen caBcum, and extends 
 to the torcular Herophili, Fig. 8, a; increasing in size from 
 its commencement to its termination. When cut transversely, 
 it presents a triangular figure, with the apex directed down- 
 
OF THE MEMBRANES OF THE BRAIN. 55 
 
 wards. The middle glands of Pacchioni are situated in it; 
 often these are very small or entirely absent. The mouths 
 of the veins of the pia mater will be seen opening into it. 
 Fibrous bands stretch across it ; they are called the chordce 
 Willisii. These cords, however, are not very distinct. The 
 superior longitudinal sinus receives blood from the nose and 
 frontal sinus, from the diploe, pericranium, and dura mater, 
 as well as from the veins of the pia mater. 
 
 An incision should now be made through the dura mater 
 corresponding to the one made in the bone for removing the 
 calvaria. Eaising it up on each side from the arachnoid, 
 its serous surface will be observed, and, tracing it towards the 
 median line, it will be found to be reflected down between 
 the two hemispheres of the brain. This reflected or vertical 
 portion is the/ate cerebri. Before raising the falx, it will be 
 necessary to divide the veins of the pia mater. It will be 
 observed that many of these enter the longitudinal sinus in 
 a direction from behind forwards; this arrangement has a 
 tendency to prevent these veins being too rapidly emptied, 
 which would be liable to cause syncope. The internal glands 
 of Pacchioni are found on the inner surface of the dura 
 mater, near the longitudinal sinus. 
 
 By separating the hemispheres a short distance, the falx, 
 Fig. 9 (s), can be seen in situ. Its lower border is concave, 
 and corresponds to the upper surface of the corpus callosum, 
 which it nearly touches behind. It is attached anteriorly to 
 the crista galli, and posteriorly to the tentorium ; its anterior 
 extremity is quite narrow, while its posterior extremity is 
 broad. The inferior or concave border contains the inferior 
 longitudinal sinus, Fig. 8, c, which resembles in its form an 
 ordinary vein. The falx may be divided just above its ante- 
 rior attachment, and turned backwards out of the way for 
 the present. 
 
 The upper part of the cerebrum is now covered by the 
 arachnoid and pia mater, through which the convolutions 
 are clearly seen. The size and direction of the veins of the 
 pia mater may be noticed. On separating the hemispheres, 
 the arachnoid will be seen reflected from one to the other 
 without reaching to the bottom of the fissure. The pia mater 
 lines the fissure throughout its whole extent. The arteries 
 of the corpus callosum are seen resting on it anteriorly, but 
 dividing into branches as they pass backwards. 
 
56 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 9. 
 
 1. Vertical section of the head. 2. The frontal sinu?. 3. The falx cerebri. 
 4. Its origin from the crista galli. 5. Its attachment along the sngital suture. 6. 
 The lower or concave edge of the falx. 7. Its continuation to the tentorium. 8. 
 The tentorium. 9. Its attachment to the petrous portion of the temporal bone. 
 10. The free edge of the same part. 11. The convolutions of the right anterior 
 lobe of the cerebrum. 12. The anterior extremity of the corpus callosum. 13. The 
 septum lucidum. 14. Section of the anterior commissure. 15. Anterior crus of the 
 furnix. 16. Middle of the fornix. 17. Its posterior extremity joining the corpus 
 callosum. 18. Internal side of the thalatnus nervi optici. 19. Section of the corpus 
 striatum. 20. Lateral parietes of the third ventricle. 21. A portion of the dura mater 
 turned off. 22. Section of the internal carotid artery. 
 
 SECT. Y. DISSECTION OF THE BRAIN. 
 
 By removing a portion of the arachnoid and pi a mater 
 above the corpus callosum, this body may be inspected before 
 any dissection of the brain is made ; its depth from the upper 
 surface of the brain, and the distance of its anterior and 
 posterior borders from the extremities of the cerebrum, are 
 worthy of notice. It is important that the student obtains a 
 distinct idea of the situation of this body in relation to the 
 periphery of the brain, as it will assist him greatly in learn- 
 ing and fixing in his mind the exact location of many other 
 parts. It is the great starting point in dissecting the central 
 or figurative part of the brain from above downwards. 
 
 Before commencing the dissection of the cerebrum, the 
 student may observe the appearance and general arrangement 
 of the convolutions of the two hemispheres. The depth of 
 the sulci, between the convolutions, is best seen from sec- 
 
THE CEREBRUM. 57 
 
 tions of the brain. The convolutions on the two sides do 
 not exactly correspond in their direction or number. This, 
 however, does not interfere at all with the functions of the 
 organ. 
 
 The dissection of the brain is begun by making a hori- 
 zontal transverse incision through one hemisphere on a level 
 with the upper. surface of the corpus callosum. In doing this, 
 the corpus callosum is kept in view, and answers for a guide. 
 The following points are now to be noticed : Just above the 
 corpus callosum, and projecting somewhat over it, is a long 
 convolution, not only extending the whole length of it, but 
 bending downwards both before and behind, to terminate on 
 the base of the brain. If the medullary substance in this 
 convolution be examined in that portion of the hemisphere 
 which has been removed, it will be found to contain longitu- 
 dinal fibres. These fibres constitute the superior longitudinal 
 commissure, and are supposed to connect, physiologically, the 
 anterior, middle, and posterior portions of the hemisphere. 
 
 The CORPUS CALLOSUM, Fig. 10, is about three inches and 
 a half in length. It is arched from before backwards, broader 
 behind than before, and thinnest in the middle. Two ridges 
 are seen on the upper surface, close to the median line, 
 extending from its anterior to its posterior border; these 
 ridges are not always parallel to each other. The raphe is 
 situated in the median line. The linece transversce are slight 
 elevations extending from the longitudinal ridges to the later- 
 al borders ; they indicate the direction of the fibres of which 
 the corpus callosum is composed. The termination of the 
 corpus callosum, neither anteriorly nor posteriorly, can be 
 seen at this stage of the dissection. It may be stated here, 
 however, that it passes downwards and backwards, in front, to 
 the lamina cinerea, or the anterior part of the floor of the 
 third ventricle. Its reflected portion gradually diminishes in 
 thickness to its termination. The term genu, or knee, has been 
 applied to the junction of the horizontal and reflected por- 
 tions, and rostrum to the lower part, just in front of the floor 
 of the third ventricle. Posteriorly, it seems to be doubled 
 upon itself, the lower or reflected part apparently terminating 
 in the posterior extremity of the fornix, forming the upper 
 boundary of the transverse fissure at this point. Laterally, 
 the fibres of the corpus callosum are lost in the hemispheres. 
 
58 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 The corpus callosum forms the roof of the two lateral ven- 
 tricles, and has attached to its under surface, along the median 
 line, the septum lucidum. The next thing to be done is to 
 
 Fig. 10. 
 
 A VERTICAL SECTION IN THE MEDIAN PLANE, OF THE CEREBRUM, CEREBELLUM, 
 PONS, AND MEDULLA OBLONGATA THE PARTS BEING ALL REPRESENTED IN THEIR 
 NATURAL POSITION. a. Anterior, and 6. Posterior extremity of corpus callosum, 
 which is seen in section, d, c, e. Third ventricle, c. Soft commissure, d, e. Thal- 
 anms opticus, forming side of third ventricle, f. Fornix, united behind to corpus 
 callosum. b, g. Anterior pillars of fornix. Between g and h, anterior commissure. 
 Behind h, lamina cinerea. h, h', h". Convolution of corpus callosum or gyrus forni- 
 catus. i. Infundibulum. k. Corpora quadrigemina, seen in section, k to I. Valve 
 of Vieussens. 1. Section of cerebellum, showing white and gray matter appearance 
 named arbor vitae. in. Notch of cerebellum. . Corpus albicans of right side, 
 o. Pons Varolii (section), p. Pituitary body. r. Choroid plexus. . Septum lu- 
 cidum. t. Cerebral peduncle of right side, in section, u. Pineal gland, v. Cavity 
 of fourth ventricle, d to v. Iter a tertio ad quartum ventriculum, or aqueduct of 
 Sylvius, x, x', x". Marginal convolution of the longitudinal fissure, y. Posterior 
 lobe of cerebrum, z. Opening leading into fourth ventricle. 1. Olfactory nerve. 
 2. Optic nerve divided through optic commissure. 3. Third nerve, or motor oculi. 
 
 expose the parts beneath the corpus callosum, without in- 
 juring them. As the septum lucidum is attached to this body, 
 the central part of it must be allowed to remain while the 
 lateral portions of it are removed. This can be done by 
 making an incision through it on each side of the raphe, and 
 about a line from the latter, from near the anterior to the pos- 
 
THE CEREBRUM. 59 
 
 terior border. Having cut into the ventricles, and observed the 
 thickness of the corpus callosum, it may be reflected outwards 
 on each side, or cut away with the scissors. The incision on 
 each side should be extended backwards and outwards for a 
 short distance in the direction of the lateral cornu, so as to 
 expose more fully the ventricje and its contents. 
 
 The SEPTUM LUCIDUM, Fig. 10, s, will now be seen forming a 
 vertical septum between the two lateral ventricles. By lifting 
 up the central portion of the corpus callosum between the 
 handles of two scalpels, and placing a light on the opposite 
 side, its translucent character will be seen. It has the shape of a 
 falx, with its broad extremity situated anteriorly, and its poste- 
 rior extremity tapering to a point between the corpus callosum 
 and fornix. It consists of two lamellae of medullary sub- 
 stance, separated by a small space called the fifth ventricle. 
 
 The FIFTH YENTRICLE is situated in the anterior part 
 of it; and to demonstrate it, the upper part of the septum 
 should be cut away with the scissors. Sometimes the two 
 Iamella3 adhere to each other, and again they are separated 
 by a small quantity of fluid. The fifth ventricle does not 
 usually communicate with the third ventricle. 
 
 The LATERAL VENTRICLE, Fig. 11, on each side, consists of 
 a body and three cornua, one for each lobe of the hemisphere. 
 The anterior cornu is the space between the reflected portion 
 of the corpus callosum and the anterior extremity of the 
 corpus striatum. The examination of the posterior and middle 
 cornua may be postponed until the body of the ventricle has 
 been studied. The body presents three surfaces: the upper, 
 or corpus callosum ; the inner, or septum lucidum ; and the 
 lower, or floor, which is composed of several parts. Of these 
 parts, there are five which deserve special notice. They are 
 the corpus striatum, tsenia semicircularis, thalamus opticus, 
 plexus choroides, and fornix. 
 
 The CORPUS STRIATUM, Fig. 11, &, forms the outer and an- 
 terior part of the floor of the ventricle. It is pear-shaped, with 
 the large extremity situated anteriorly, and the small extrem- 
 ity posteriorly. It is readily distinguished from the surround- 
 ing parts by its dark-grayish color. It is called the striated 
 body, on account of the intermixture of gray and white sub- 
 stance in its structure, which gives to it a striated appearance 
 
60 DISSECTION OF THE HEAD AND NECK. 
 
 when it is cut into. The external portion of the brain corre- 
 sponding to the corpus striatum is the island of Reil, in the 
 fissure of Sylvius. 
 
 THE T^ENTA SEMICIKCULAKIS, Fig. 11, s, is a narrow, whitish 
 band, situated along the inner concave border of the corpus 
 
 A 
 
 Fig. 11. 
 
 SECTION OP CEREBRUM, DISPLAYING THE LATERAL VENTRICLES. ON THE RIGHT 
 SIDE, THE DESCENDING CORNU is LAID OPEN. a, b. Parts of great longitudinal fissure. 
 c. Section of front of corpus callosum. d. Part of posterior end of the same. f. The 
 body of the fornix. e. The left choroid plexus, g. Anterior cornu, k, posterior, and 
 q, descending cornu of the lateral ventricle, k, k. Corpora striata. I, I. Optic thai- 
 ami. , n. Right and left hippocfimpus minor, o. Posterior pillar of fornix, be- 
 coming continued as the corpus fimbriatum, v. q. Cornu Ammonis, or Pes hippocampi. 
 r. Shows alternate gray and white layers in cortical substance, s, *. Right and left 
 tsonia semicircularis. v. Corpus fimbriatum. y. Eminentia collateralis. 
 
 striatum. It extends from the anterior cornu of the fornix 
 to the posterior part of the thalamus opticus, where it is con- 
 nected to the corpus geniculatum externum. 
 
 The THALAMUS NERVI OPTICI, Fig. 11, Z, is seen on the 
 inner side of the toenia semicircularis, by which it is separated 
 from the posterior part of the corpus striatum. It is white, 
 
THE CEREBRUM. 61 
 
 and only a small portion of it is seen in the floor of the 
 lateral ventricle. 
 
 The PLEXUS CHOROIDES, Fig. 11, e, is composed of vessels 
 and are'olar tissue, being a portion of the pia mater. It is 
 situated on the inner side of the thalamus. It is red in the 
 recent brain. 
 
 The FORNIX, Fig. 11, /, is a white body forming the inner 
 part of the floor. Anteriorly, it is connected with the septum 
 lucidum; and posteriorly, with the corpus callosum. 
 
 Besides these five bodies, the student may notice along the 
 concave border of the corpus striatum a narrow, shining 
 band, called the Lamina Cornea. This is apparently a 
 thickening of the lining membrane of the ventricle. It is 
 not always very distinct. Beneath this is a vein of consider- 
 able size, coming from the corpus striatum. The floors of the 
 two lateral ventricles are perfectly symmetrical. 
 
 The POSTERIOR CORNU of the lateral ventricle, Fig. 11, h, 
 is an extension into the posterior lobe. It proceeds outwards 
 at first, and then inwards. Its floor is formed by a spur- 
 shaped elevation called the HIPPOCAMPUS MINOR. The upper 
 and lateral walls consist of white medullary substance. 
 
 The MIDDLE or INFERIOR CORNU, Fig. 11, q, is much larger. 
 It curves outwards, downwards, and forwards around the 
 posterior, outer and lower part of the thalamus. This cavity 
 may be exposed by removing the upper and outer portion 
 of the middle lobe down to a level with it ; or it may be 
 fully brought into view by making a single incision, cutting 
 from within outwards, and following the course of the corriu 
 from its commencement to its termination, and then lifting 
 up that portion of the middle lobe situated above it. The 
 following parts are found in the middle cornu. 
 
 The plexus choroides extends into the middle cornu, and dis- 
 appears there, by becoming continuous with the pia mater in 
 the transverse fissure ; this must be removed to expose the 
 parts beneath it. 
 
 The HIPPOCAMPUS MAJOR extends the whole length of the 
 
 floor, and terminates in an indented expansion, called the 
 
 pes hippocampi. This body follows the curved direction of 
 
 the cavity ; presents a smooth white appearance, convex ex- 
 
 G 
 
62 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 ternally and concave internally. This body is formed by 
 the posterior and reflected portion of the convolution which 
 was seen on the inner side of the hemisphere, immediately 
 above the corpus callosum ; it has a corresponding depres- 
 sion or sulcus on the base of the brain. 
 
 The T^NIA HIPPOCAMPI, or CORPUS FIMBRIATUM, is a nar- 
 row white band occupying the concave border of the hippo- 
 Fig. 12. 
 
 A SECTION or THE CEREBRAL HEMISPHERES, SHOAVING BOTH LATERAL VENTRI- 
 CLES, AFTER THE FORNIX HAS BEEN DIVIDED AND TURNKD BACK, TO EXPOSE THE 
 
 VELTJM INTERPOSITUM. c. The anterior portion of corpus callosum, cut across, e. 
 The lyra, or under surface of posterior part of corpus callosum. /. Anterior pillars 
 of fornix cut across. N. B. These are represented of too great size. g. Anterior, 
 h, posterior cornu of lateral ventricle, k, k. Corpora striata. q. Pes hippocampi. 
 r, r. Thalami optici. a, s. Teenia semicircularis. t, t. Choroid plexuses, v. Velum 
 interpositum. x, x. Posterior pillars of fornix. y. Eminentia collateralis. 
 
 campus major; it is a continuation of the posterior pillar of 
 the fornix; its concave border is free, while its convex mar- 
 gin can usually be raised only slightly from the hippocampus. 
 
THE CEKEBEUM. 63 
 
 When the free border of the corpus fimbriatum is raised up 
 and turned over on the hippocampus, the CORPUS DENTATUM 
 is brought into view. It is a reddish gray body, serrated, 
 and lies within the concavity of the hippocampus. 
 
 The internal and upper wall of the middle cornu is formed 
 by the thalamus opticus and corpus striatum. On the lower 
 and posterior part of the thalamus may be observed two 
 small bodies, the corpus geniculatum,, externum and inter- 
 num. The latter is located a little anterior to and below 
 the former ; it is also somewhat smaller, and of a paler ap- 
 pearance. These bodies are connected by white bands to 
 the tubercula quadrigemina. The optic nerve arises in part 
 from them. 
 
 Having observed the walls and contents of the lateral 
 ventricles, the student may proceed with the dissection in 
 the direction of the third ventricle. 
 
 This ventricle is situated under the fornix, which has not 
 as yet been disturbed. By observing the point at which 
 the plexus choroides on each side passes beneath the fornix, 
 the position of the foramen of Monroe will be found, as it is 
 occupied by the junction of the two plexuses. This foramen 
 forms the only direct communication between the lateral 
 ventricles, and also between them and the third ventricle. 
 
 Now divide the fornix over the foramen of Monroe, and 
 carefully raise up and reflect one portion forwards and the 
 other backwards. The union of the two plexuses will now 
 be seen, and also a thin delicate membrane stretching across 
 from one plexus to the other, and which lined the inferior 
 surface of the fornix behind the foramen of Monroe ; this is 
 called the velum interpositum, Fig. 12, v. The handle of the 
 scalpel should now be carried backwards between the fornix 
 and the velum interpositum, separating the latter from the 
 former, and also from the posterior border of the corpus 
 callosum. On the under surface of the posterior part of the 
 corpus callosum, and between the posterior pillars of the 
 fornix, are several oblique lines, which constitute what is 
 called the lyra, Fig. 12, e. By dividing what remains of the 
 posterior part of the corpus callosum and fornix, in the 
 direction of the median line, the connection between these 
 two bodies may be examined; also the manner in which the 
 fornix is connected on the sides with the two hippocampi and 
 the corpora fimbriata. These last connections form the poste- 
 
64 DISSECTION OF THE HEAD AND NECK. 
 
 rior pillars, or crura, Fig. 12, x, x, of the fornix, of which there 
 is one on each side. It will be observed that the borders of 
 the central part of the fornix are entirely free, resting upon 
 the plexuses and the velum interpositum. The anterior part 
 of the fornix divides into two crura, which pass downwards 
 towards the base of the brain. These will be seen more 
 distinctly when the third ventricle is fairly exposed. 
 
 The velum interpositum may now be raised and reflected 
 backwards, observing, at the same time, two veins, the vence, 
 Galeni, Fig. 8, e, occupying the centre of it. These veins col- 
 lect the blood from the different bodies in the ventricles and 
 convey it into the sinus rectus. In separating the pia mater 
 from the substance of the brain, care should always be taken 
 to divide with the scalpel or scissors any small vessels which 
 are not readily broken. In raising the posterior part of the 
 velum, it should be borne in mind that it is closely connected 
 to the pineal gland, and that this part of it, therefore, should 
 be dissected, and not torn away. With a little care, and by 
 using the forceps and scissors, the student will be able to 
 preserve this small body with its connections to the thalami 
 and posterior commissure of the third ventricle. 
 
 The THIRD YENTRICLE, Fig. 13, z to s, should now be exam- 
 ined. It is located between the thalami nervorum opticorum 
 and below the fornix and velum interpositum ; the locus per- 
 foratus medius, eminentise mammillares, and tuber cinereum, 
 which are seen on the base of the brain, are placed imme- 
 diately below it. It contains three commissures, ax^anterior, 
 a middle, and a posterior. The middle one is not a true com- 
 missure; it consists of gray substance, formed apparently 
 by a mere adhesion of the two thalami. It is apt to be 
 broken away in separating the bodies to expose the other 
 parts in the ventricle. It is sometimes absent. In the ante- 
 rior part of the ventricle are seen, first, the anterior crura of 
 the fornix, having a vertical direction ; second, in front of, and 
 between these, the anterior commissure, a small transverse 
 cylindrical body connecting the corpora striata and the con- 
 volutions of the middle lobes ; and third, below this, and 
 between the crura, the opening which leads into the infundib- 
 ulum. In the posterior part are observed, first, the peduncles 
 of the pineal gland, which extend forwards along the inner 
 margins of the thalami, to which they adhere, to connect 
 with the anterior crura of the fornix and the taenia semi- 
 
THE CEREBRUM. 
 
 65 
 
 circulares ; second, the posterior commissure, a white, cylindri- 
 cal body, which connects the two thalami; third, just beneath 
 this, the aqueduct of Sylvius, or the opening which leads to 
 the fourth ventricle. The floor of the third ventricle is only 
 
 Fig. 13. 
 
 SECTION OP THE CEREBRUM DISPLAYING THE SURFACES OP THE CORPORA STRIATA, 
 AND OPTIC THALAMI, THE CAVITY OP THE THIRD VENTRICLE, AND THE UPPER SUR- 
 FACE OF THE CEREBELLUM. a, e. Tubercula quadrigemina e, testis, a, nates, c. Cor- 
 pus callosum. /. Anterior pillars of fornix. </. Anterior cornu of lateral ventricle. 
 k, k. Corpora striata. I, 1. Optic thalaini. * Anterior tubercle of the left thalamus. 
 z to s. Third ventricle. In front of z, anterior commissure. 6. Soft commissure. 
 . Posterior commissure, p. Pineal gland with its peduncles, n, n. Processus cere- 
 belli ad testes. m, m. Hemispheres of the cerebellum, h. Superior vermiform 
 process, i. Notch behind the cerebellum. 
 
 about a line in thickness, so that this cavity is situated very 
 near to the basilar surface of the brain. 
 
 The PINEAL GLAND, Fig. 13, p, has already been exposed. 
 It is of a pyriform shape, with its base turned forwards and 
 upwards, and consists of gray matter, which contains small, 
 
66 DISSECTION OF THE HEAD AND NECK. 
 
 calcareous bodies. It generally contains a small cavity. It 
 rests on the tubercula quadrigemina, and beneath the poste- 
 rior border of the corpus callosum. 
 
 Directly behind the third ventricle are found the TUBER- 
 CULA QUADRIGEMINA, Fig. 13, a, e. They consist of four 
 round tubercles or elevations, separated on the surface by 
 grooves, but joined at their bases. They occupy a plane in- 
 clined obliquely backwards and downwards. The anterior 
 and superior are called nates; the posterior and inferior are 
 named testes, and are smaller than the nates. They, with the 
 posterior commissure, form the roof of the way from the third 
 to the fourth ventricle, or the aqueduct of Sylvius. 
 
 Before proceeding further with the dissection, it will be 
 necessary to remove the encephalon from the cavity of the 
 cranium. It might be taken out before the dissection of the 
 cerebrum is commenced. This is not necessary, however, if 
 it can be examined when fresh, or if the subject has previously 
 been injected with solution of chloride of zinc. To remove 
 the encephalon, the subject should be placed on the back, 
 with a block under the shoulders, so that the head can be 
 depressed sufficiently to allow it to rest on one hand, while 
 the vessels, nerves, &c., are divided with the other. 
 
 In raising the anterior lobes, the bulbs of the olfactory 
 nerves must be removed with some care from the cribriform 
 fossae ; or they may be allowed to remain for the purpose of 
 examining them afterwards in situ. The optic nerves must be 
 divided at the sella turcica, just before they enter the optic 
 foramina ; also the internal carotids. Immediately behind the 
 optic chiasm, which will now be seen, is the infundibulum, 
 extending from the tuber cinereum, on the base of the brain, 
 to the pituitary gland, which occupies the sella turcica ; this 
 may be cut across, if it be desired to examine the gland 
 in situ, otherwise the scalpel may be carried around it so 
 as to remove the greater part of it in connection with the 
 infundibulum. The whole of the pituitary body cannot 
 well be dissected out without cutting away the posterior 
 clinoid processes. The infundibulum is very easily broken, 
 hence some care is necessary to preserve it. The third pair 
 of nerves will be seen perforating the dura mater behind, and 
 outside of the posterior clinoid processes. The fourth pair 
 run along the margin of the tentorium; they are very small, 
 
THE CEREBRUM. 67 
 
 and usually lie concealed just beneath its edge. The fifth 
 pair are large, and perforate the dura mater a little below 
 the margin of the tentorium ; they are readily exposed by 
 cutting through the tentorium directly over them.. The 
 sixth pair are much smaller, and will be seen a little further 
 back and nearer to the median line. The seventh pair are 
 situated more externally, and nearer to the petrous portion 
 of the temporal bone. The eighth pair consist of several 
 fasciculi, and are a little nearer to the median line and further 
 back than the preceding. The ninth pair will be observed 
 near the foramen occipitale. These nerves must all be 
 divided, as they are brought into view, with a sharp scalpel 
 or with the scissors. The tentorium must be cut through on 
 each side before all the nerves can be divided. The spinal 
 marrow is to be cut across by carrying the scalpel as far 
 down as convenient through the occipital foramen, care being 
 taken, at the same time, to sever the vertebral arteries. 
 Having divided all these parts, the brain is easily removed 
 by carrying one or two fingers down so as to dislodge the 
 medulla oblongata and cerebellum, while the whole is steadied 
 and carefully supported with the other hand. It is hardly 
 necessary to remind the student of the necessity of handling 
 the encephalon with great care, in order to preserve it entire. 
 
 If the cerebellum now be pushed a little backwards, and 
 away from the testes, the valve of the brain and the processus 
 cerebelli ad testes, Fig. 13, n, will be seen. To obtain a good 
 view of these, the student may divide the cerebellum in the 
 median line and down to -a level with the valve. Having 
 examined the valve in situ, he may continue the incision to 
 near the base of the cerebellum. Thus, dividing this organ 
 need not interfere with its examination at another time. 
 
 The interior of the FOURTH VENTRICLE, Fig. 10, v, Fig. 16, 
 will be distinctly seen by separating the two halves of the 
 cerebellum. It consists of a lozenge-shaped space, situated 
 behind and below the tubercula quadrigemina, which sepa- 
 rate it from the third ventricle. Its boundaries are formed 
 by the medulla oblongata. the cerebellum, and the cerebrum, so 
 that it may be regarded as a space occurring incidentally 
 between all these parts. The object to be gained by studying 
 it as a cavity is simply to learn the location of the parts with 
 which it is in relation. 
 
 Its floor is formed by the upper and posterior surface of 
 the medulla oblongata ; its roof is arched from above down- 
 
68 DISSECTION OF THE HEAD AND NECK. 
 
 wards and from before backwards, and may be considered as 
 curved laterally with the concavity looking towards the 
 ventricle. 
 
 The following parts enter into the formation of its roof: 
 In the upper and anterior part are the valve of the brain 
 and the processus cerebelli ad testes. The VALVE is of a tri- 
 angular shape, the apex being joined above by a narrow 
 band to the testes, the base to the cerebellum, and the sides 
 to the processus cerebelli ad testes. It consists of a thin 
 .white lamina, covered by a layer of gray substance. Its 
 upper surface, especially near the base, presents several trans- 
 verse ridges, resembling the lamellated arrangement of the 
 cerebellum. The FOURTH PAIR of nerves arise from it and the 
 processes on its sides. 
 
 The PROCESSUS CEREBELLI AD TESTES are two bands of 
 medullary fibres, one extending from the centre of each 
 hemisphere of the cerebellum to the testes, and through them 
 to the cerebrum. In the lower and posterior part of the roof 
 there are, in the median line, two projections ; the upper one 
 is named the nodulus, the lower one the uvula. These promi- 
 nences are situated on the inferior vermiform process on the 
 lower part of the median lobe of the cerebellum. On each 
 side of the uvula, and united to it, is a small protuberance 
 termed the tonsil. Extending from the flocculus or pneumo- 
 gastric lobe on the one side, to the nodulus in the centre, and 
 thence across to the corresponding lobe of the opposite side, 
 may be seen a thin, white, delicate membrane, composed of 
 transverse fibres, and named the posterior medullary velum. 
 It forms a commissural connection between the parts with 
 which it is connected. It presents a free, concave border, 
 which looks into the ventricle. 
 
 The following points are observed in the floor of the fourth 
 ventricle : A fissure is seen in the median line extending 
 from the lower orifice of the aqueduct of Sylvius above, to 
 a slight depression in the medulla oblongata called the ven- 
 tricle of Arantius. The lower part of this fissure is named 
 the calamus scriptorius. The whole length of the fissure is 
 about an inch and a half. The corpora restiformia commence 
 at the ventricle of Arantius, and diverge as they pass up- 
 wards and outwards to enter the cerebellum. In the upper 
 part are the crura cerebslli, which are composed of the trans- 
 verse medullary fibres of the pons Varolii, and are here seen 
 
THE CEREBELLUM. 69 
 
 entering the cerebellum. The posterior pyramids are two 
 bodies, one on each side of the lower part of the fissure. 
 The superior surface of the pons Yarolii forms a part of the 
 floor just behind and below the tubercula quadrigemina. 
 The fasciculi innominati, or corpora teretes, also pass up 
 through the posterior part of the medulla oblongata, and in 
 the floor of the fourth ventricle. In the lower part of the 
 floor are observed white transverse fibres, called linece trans^ 
 versa. The PORTIO MOLLIS arises in part from some of these 
 fibres. A thin layer of gray neurine covers the greater part 
 of the walls of this cavity, and the whole is lined by a serous 
 membrane, which is continued into the third ventricle through 
 the aqueduct of Sylvius, but not into the subarachnoid space 
 immediately below. 
 
 The pia mater sends into the fourth ventricle two pro- 
 longations called chor oid plexuses. Before proceeding farther 
 with the dissection, the reflection of the arachnoid from the 
 cerebellum to the medulla oblongata should be noticed. 
 Quite a space is left beneath it, occupied principally by 
 areolar tissue. This is called the posterior subarachnoid space. 
 It will be observed that the arachnoid adheres closely to the 
 surface of the medulla oblongata, so that fluid cannot readily 
 pass from the posterior subarachnoid space in the cranium, 
 to the one in the spinal canal. It may be remarked here, 
 that the subarachnoid spaces in the cranium communicate 
 for the most part freely with each other. 
 
 THE CEREBELLUM. 
 
 The dissection of the CEREBELLUM may now be commenced. 
 Some of its parts have already been noticed in connection 
 with the fourth ventricle. Its location and relations in the 
 cranial cavity were seen at the time the encephalon was 
 removed. It differs in form and external appearance very 
 materially from the cerebrum. Its transverse diameter is 
 greater than the antero-posterior, while its two hemispheres 
 are connected above and below by elevations. Instead of con- 
 volutions, its exterior surface presents numerous concentric 
 lamellae separated by sulci ; these have, for the most part, a 
 transverse direction, and are more numerous on the upper 
 than on the lower surface. It is composed of white medul- 
 lary substance internally, and gray matter externally. The 
 
70 DISSECTION OF THE HEAD AND NECK. 
 
 gray substance, however, does not cover the bottoms of the 
 deep sulci. Its superior and inferior surfaces are separated 
 by a well marked border, and a deep horizontal fissure. It 
 presents two notches, one before for the tubercula quadri- 
 gemina and the crura cerebelli, and one behind for the falx 
 cerebelli and inferior occipital ridge. The posterior notch 
 terminates below and anteriorly in an excavation which cor- 
 responds to the medulla oblongata. 
 
 The two hemispheres are united by a median lobe, the upper 
 part of which is termed the superior vermiform process, and 
 the lower part the inferior vermiform process. The upper sur- 
 face is sloping from the centre, while the under surface of 
 each hemisphere is convex, and separated by a deep depres- 
 sion, named the vallecula, or valley. 
 
 The superior surface, Fig. 14, of each hemisphere presents 
 two lobes ; an anterior, or square lobe, and a posterior, or semi- 
 
 te. 14. 
 
 A VIEW OF THE SUPERIOR FACE OP THE CEREBELLUM. 1,1. The circumference 
 of the cerebellum. 2. The space between its hemispheres behind. 3. One of the 
 hemispheres of the cerebellum, showing the lamellae which compose it. 4. The 
 superior vermiform process. 5. The tubercula quadrigemina. 6. Section of the 
 crura cerebri. 
 
 lunar lobe, divided by a deep sulcus. The two anterior lobes 
 are connected to each other by the transverse laminas of the 
 superior vermiform process, which is situated between them. 
 The two posterior lobes are separated from each other by 
 the posterior notch, but are connected to each other by trans- 
 verse bands at the bottom of the notch. These lobes consist 
 of lobules, which again are composed of laminos. 
 
THE CEREBELLUM. 71 
 
 The inferior surface, Fig. 15, of each, hemisphere presents 
 five lobes separated by sulci. 
 
 The inferior posterior lobe is situated immediately below the 
 superior posterior, and separated from its fellow by the pos- 
 terior notch. 
 
 The digastric lobe is larger, and is seen near the anterior 
 and external border of the hemisphere. This lobe is con- 
 nected to its fellow on the opposite side by transverse lamellae, 
 which extend through the pyramid across the valley. Its 
 outer extremity is broad, and divided into two parts. 
 
 The gracilis lobe is situated between the two preceding. It 
 
 has a transverse direction, 
 'i 
 
 Fig. 15. 
 
 A VIEW OF THE INFERIOR SURFACE OF THE CEREBELLUM AND A PORTION or THE 
 MEDULLA OBLONGATA. 1,1. The circumference of the cerebellum. 2,2. The two 
 hemispheres of the cerebellum. 3. Lobus amygdaloides. 4. The inferior ver- 
 miform process. 5. Lobus nervi pneumogastrici. 6. The calamus scriptorius. 
 7. Its point. 8. Section of the medulla oblongata. 9. Points to the origin of the 
 pneumogastric nerve. 
 
 The flocculus, or pneumogastric lobe, Fig. 15 (s), is attached 
 to the hemisphere by a pedicle. It is situated anteriorly by 
 the side of the valley, and just behind the crus cerebelli, 
 close to the eighth nerve. Its surface is divided into small 
 lamellae. The two flocculi, as before mentioned, are con- 
 nected to each other by the posterior medullary velum. 
 
 The amygdaloid, or tonsillitic lobes, were seen in the dissec- 
 tion of the fourth ventricle. These two lobes form the lateral 
 boundaries of the valley, and are connected to each other by 
 the uvula. 
 
 The superior vermiform process extends from the posterior 
 
72 DISSECTION OF THE HEAD AND NECK. 
 
 to the anterior notch. It is much larger anteriorly where it 
 overhangs the valve of the brain, and is in apposition with 
 the tubercula quadrigemina, than it is posteriorly. It is 
 crossed by curved lamellae, which are convex anteriorly. 
 
 The inferior vermiform process has a crucial form. The pos- 
 terior limb projects backwards in the posterior notch, the 
 anterior extends forwards into the fourth ventricle, while the 
 lateral or transverse are connected to the hemispheres. It 
 presents in the median line three prominences : the pyramid 
 behind, next to this, in front, the uvula, and anterior to this 
 the nodulus. The last two form a portion of the roof of the 
 fourth ventricle. 
 
 The internal structure of the cerebellum may be seen 
 by making two vertical incisions from before backwards, 
 commencing at the anterior notch. One of these incisions 
 should divide the middle lobe in the median line; the other 
 
 Fig. 16. 
 
 A VIEW OF THE ARBOR VITJS AND THE FUNDAMENTAL PORTION OF THE CEREBEL- 
 LUM, TOGETHER WITH THE FLOOR OF THE FOURTH VENTRICLE. 1. The tubercula 
 
 qnadrigemina. 2. The superior surface of the cerebellum. 3. Its inferior surface, 
 and also the arbor vitae. In the trunk of the arbor vitse are seen three fasciculi 
 running up to the tubercula quadrigemina. The most internal of these is 4. A fibrous 
 layer, in which are collected all the filaments which pass from the parietes of the 
 aqueduct of Sylvius to the inferior vermiform process. 5 Is the fasciculus outside 
 of the preceding, which runs from the trunk of the arbor vitse behind the tubercula 
 quadrigemina. 6 Is that from which all the fasciculi of the superior vermiform 
 process pass to the tubercula quadrigemina. 7. A very delicate medullary layer, 
 which passes from the anterior surface of the crus cerebelli under the cineritious 
 matter of the cerebrum. 8. The anterior extremity of the fourth ventricle, drawn 
 back and leading to the aqueduct of Sylvius. 9. Middle furrow on the floor of the 
 fourth ventricle. ]0. Tracts of nervous matter, running to the auditory nerve. 11. 
 Elevated portion of the same on the floor of the fourth ventricle. 12. Middle fis- 
 sure on the calamus scriptorius. 13. Corpora Restiforuiia. 14. Lateral portion of 
 the spiual marrow. 
 
THE MEDULLA OBLONGATA. 73 
 
 should be carried through one of the hemispheres so as to 
 leave about one-third of it on the inner side, and two-thirds 
 on the outer side. The arrangement of the white or medul- 
 lary substance is distinctly seen on the surfaces of these sec- 
 tions. It presents, in both, a beautiful arborescent appear- 
 ance, which has been named the arbor vitce. The one in the 
 middle lobe is the middle arbor vilce, and the one in the hemi- 
 sphere, the lateral arbor vitce. The central mass is the trunk 
 of the tree, and from this spring branches, which divide into 
 smaller branches, and these again into twigs and leaflets. In 
 this way the medullary fibres diverge from the centre to the 
 periphery, so as to be placed in connection with a large ex- 
 tent of cineritious surface. In the centre of the trunk of 
 the lateral arbor vitae is a mass of grayish-yellow matter, 
 with indented edges ; this is the corpus dentatum, corpus 
 rhomboideum, or the ganglion of the cerebellum. It consists 
 of a capsule of gray substance, filled with white fibres, inter- 
 mixed with gray neurine. The capsule is perforated ante- 
 riorly by the fibres of the corpus restiforme. 
 
 The CEREBELLUM is about one-eighth the size T>f the cere- 
 brum. Its white central mass is connected with the cere- 
 brum, through the processus cerebelli ad testes, and with the 
 medulla oblongata, through the corpora restiformia and the 
 arciform fibres which come from the corpora pyramidalia; 
 the two hemispheres are connected by the transverse fibres of 
 the pons Varolii. These commissural fasciculi should be 
 carefully observed by the student, as it is through them en- 
 tirely that the cerebellum is placed in relation with the other 
 parts of the nervous system. 
 
 The MEDULLA OBLONGATA, Fig. 17 (i 3), may next be exa- 
 mined. This consists of an intermediate section between the 
 spinal marrow and the cerebrum and cerebellum ; it is a sort 
 of unfolding of the spinal marrow preparatory to the con- 
 tinuation of its fibres upwards into the two bodies just men- 
 tioned. Although it is convenient to speak of it as a distinct 
 part, the student should bear in mind that it is merely a 
 portion of one continuous structure. It gives origin, it is 
 true, to nerves which have specific functions, but this does 
 not, in an anatomical point of view, isolate it at all from 
 other parts with which it is structurally connected. 
 
 It commences just below the foramen occipitale, and extends 
 
74 DISSECTION OF THE HEAD AND NECK. 
 
 upwards to the pons Yarolii. Its direction corresponds to the 
 inner surface of the cuneiform process of the occipital bone 
 and the commencement of the spinal canal. Anteriorly and 
 laterally, it is simply covered by pia mater and arachnoid 
 membrane ; posteriorly, it is, as has already been seen, in 
 relation with the cerebellum and fourth ventricle. 
 
 Each lateral half presents four elevations or bodies, named 
 corpus pyramidale, corpus olivare, corpus restiforme, and corpus 
 pyramidale posterius. The two anterior pyramidal bodies 
 are separated by a fissure, which is a continuation of the 
 anterior fissure of the spinal marrow. At the bottom of this 
 fissure are observed transverse commissural fibres; and, 
 about an inch below the upper extremity, are seen several 
 fasciculi, which decussate, connecting each half of the spinal 
 marrow with the opposite hemisphere of the brain. The 
 two posterior pyramidal bodies are also separated by a fissure, 
 which is a continuation of the posterior fissure of the spinal 
 marrow. A part of this fissure is the calamus scriptorius. 
 
 The CORPOIIA PYRAMIDALIA, Fig. 17 (2 o), are a continuation 
 of the anterior columns of the spinal marrow upwards. They 
 increase in size up to the pons Varolii, where they become 
 suddenly constricted, and immediately enter that body. They 
 diverge slightly as they ascend. At the upper end of the fis- 
 sure, and between their upper extremities, is a small depres- 
 sion, called the foramen ccecum. Each body is composed of 
 fibres coming from the anterior column of the spinal marrow 
 of its own side, and also of fibres from that of the opposite 
 side. These fibres continue upwards, through the pons Va- 
 rolii and crura cerebri, to the cerebral hemispheres. 
 
 The CORPORA OLiVARiA,Fig.l7 (2 2), are situated behind, and 
 external to the anterior pyramids. They do not extend quite 
 up to the pons ; nor are they quite as long as the pyramids. 
 The upper extremities are more prominent than the lower. 
 Externally, they consist of white fibrous tissue; internally, each 
 contains a mass of gray substance called the olivary ganglion, 
 or corpus dentatum of the olivary body. The structure and 
 appearance of this is similar to the corpus dentatum of the 
 cerebellum. On the inner side, its capsule is open, and the 
 gray matter which it contains is continuous with that of the 
 centre of the medulla oblongata; it is also continuous with 
 the gray substance of the pons. The fibres of the olivary 
 bodies are continued upwards into the upper and posterior 
 
BASE OF THE BRAIN. 75 
 
 part of the crura cerebri, and thence to the optic thalami and 
 tubercula quadrigemina. The two olivary bodies are joined 
 to each other behind the anterior pyramids, and form a part 
 of the floor of the fourth ventricle. 
 
 The CORPORA EESTIFORMIA, Fig. 17 (21), are observed be- 
 hind the olivary bodies. They are separated from each other, 
 below, by the posterior median fissure, and, above, by the 
 fourth ventricle. They are a continuation of the posterior 
 lateral columns of the spinal cord upwards to the ganglia of 
 the cerebellum. 
 
 The CORPORA PYRAMIDALIA POSTERIORA, or INNOMINATA, 
 
 are seen in the floor of the fourth ventricle, one on each side 
 of the median fissure. Their fibres extend upwards to the 
 cerebrum. 
 
 The ARCIFORM FIBRES arise from the anterior pyramids, and, 
 curving round the olivary bodies, join the corpora restiformia. 
 They are very irregular. Sometimes they are seen above and 
 below the olivary bodies, and again they spread out over them. 
 
 The grooves, between which the olivary body on each side 
 is situated, are occupied by the roots of nerves. 
 
 The BASE of the brain may now be examined. There are 
 three subarachnoid spaces to be noticed, in the first place, on 
 the base of the brain. The two lateral are formed by the 
 arachnoid passing from the lower surfaces of the middle 
 to the anterior lobes, without dipping into the fissures of 
 Sylvius. The anterior is situated in front of the pons Varolii, 
 and between the middle lobes. These spaces are filled with 
 loose areolar tissue, and are capable of containing a consider- 
 able quantity of serum. The arachnoid, where it is reflected 
 to form these spaces, is quite thick and strong. 
 
 The under surface of the brain, it will be observed, presents 
 an appearance very different from the upper. Taking the 
 encephalon, the following prominent points will be noticed: 
 On the sides, are the anterior and middle lobes of the 
 cerebrum, separated by the fissures of Sylvius ; behind 
 the middle lobes, and separated from them by the trans- 
 verse fissure, are the hemispheres of the cerebellum. Thus, 
 the encephalon presents six prominent parts, situated later- 
 ally on its inferior surface. In the space between these 
 parts, and occupying the centre, are the following, commenc- 
 ing posteriorly: The medulla oblongata, situated between 
 
76 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 the hemispheres of the cerebellum ; directly in front of this, 
 the pons Yarolii ; anterior to it, the crura cerebri, and, be- 
 
 Fig. 17. 
 
 A VIEW OF THE BASE OF THE CEREBRUM AND CEREBELLUM, TOGETHER WITH THEIR 
 NERVES. 1. Anterior extremity of the fissure which separates the hemispheres of 
 the brain. 2. Posterior extremity of the same fissure. 3. Anterior lobe of the 
 cerebrum. 4. Its middle lobe. 5. Fissure of Sylvius. 6. Posterior lobe of the 
 cerebrum. 7. A part of the infundibulum. 8. Tuber cinereum. 9. Corpora albi- 
 cantia. 10. Pons Tarini. 11. Crura cerebri. 12. Pons Varolii. 13. The top of the 
 medulla oblongata. 14. Posterior prolongation of the pons Varolii. 15. Middle of 
 the cerebellum. 16. Anterior part of the cerebellum. 17. Its posterior part, and 
 the fissure of its hemispheres. 18. Superior part of the medulla spinalis. 19. Mid- 
 dle fissure of the medulla oblongata. 20. Corpus pyramidale. 21. Corpus resti- 
 forme. 22. Corpus olivare. 23. Olfactory nerve. 24. Its bulb. 25. Its external 
 root. 26. Its middle root. 27. Its internal root. 28. Optic nerve beyond the 
 chiasm. 29. Optic nerve behind the chiasm. 30. Motor oculi, or third pair of nerves. 
 31. Fourth pair, or pathetic nerves. 32. Fifth pair, or trigeminus nerves. 33. Sixth 
 pair, or motor externus. 34. Facial nerve. 35. Auditory nerve. 36,37, 38. Eighth 
 pair of nerves. (The ninth pair are not seen.) 
 
 tween them, the locus perforatus medius and the eminentiae 
 mammillares ; in front of the eminentia3, the tuber cinereum, 
 
BASE OF THE BRAIN. 77 
 
 which is placed between the optic tracts, and behind the optic 
 chiasm ; in front of the chiasm is the fissure which separates 
 the' anterior lobes ; on the outside of each optic tract is the 
 commencement of the fissure of Sylvius, with the locus per- 
 foratus lateralis and the peduncle of the corpus callosum. The 
 relative position of these different parts on the base of the 
 encephalon, should be carefully noted by the student. 
 
 The PONS VAROLII, Fig. 17 (i 2), contains the fibres which 
 constitute the great commissure between the hemispheres of 
 the cerebellum, and also the fibres which are prolonged from 
 the medulla oblongata upwards into the crura cerebri. Be- 
 sides these two sets of fibres, more or less gray substance is 
 found in it, in which other fibres are said to originate. 
 
 It has directly above it the upper portion of the fourth 
 ventricle, the tubercula quadrigemina, and the aqueduct of 
 Sylvius. Its lower surface is free, and corresponds to the 
 upper part of the basilar process of the occipital bone. Below 
 and behind it is the medulla oblongata. In front of it are the 
 crura cerebri. Laterally it terminates in the middle pedun- 
 cles of the cerebellum. 
 
 When the pons is cut into, the transverse fibres are found 
 to be intersected by Jongitudinal fasciculi, which are easily 
 traced from the corpora pyramidalia upwards to the crura 
 cerebri. The transverse fibres which are placed above the 
 longitudinal fasciculi have gray substance intermixed with 
 them. This gray substance is also intermixed with the fibres, 
 which are prolonged upwards from the corpora olivaria. 
 Above the gray substance are the fibres which proceed from 
 the corpora innominata to the upper part of the crura cerebri. 
 
 The CRURA CEREBRI, or the PEDUNCLES OF THE CEREBRUM, 
 Fig. 17 (i i), are two large white bodies placed in front of the 
 pons Yarolii. They are to be regarded as a continuation of the 
 spinal marrow upwards to the base of the cerebrum. They 
 consist of white fibres which have ascended through the pons 
 from the medulla oblongata and those which have originated 
 in the pons, together with a mass of gray matter in each crus 
 named the locus niger. The inferior fibres are a continuation 
 of those which compose the corpora pyramidalia ; the superior 
 fibres are a continuation of those of the corpora olivaria and 
 innominata. The gray matter is situated between these two 
 sets of fibres, and in the central part of each crus. The gray 
 
 7* 
 
78 DISSECTION OF THE HEAD AND NECK. 
 
 matter of the two crura is connected by the pons Tarini. It 
 is continuous below with the gray neurine of the pons, me- 
 dulla oblongata, and spinal marrow, and above, with that of 
 the corpora striata and optic thalami. 
 
 If the fibres of the crura be traced upwards into the 
 cerebral hemispheres, they will be found to enter the gray 
 matter of the corpora striata and optic thalami ; the inferior 
 fibres, or those from the corpora pyramidalia, pass into the 
 striated bodies, and the superior fibres, or those from the 
 corpora olivaria and innominata, into the optic beds. This is 
 true, however, only to a certain extent. The termination of 
 these fibres in the optic thalami and striated bodies varies ; 
 some seem to form a plexiform arrangement in them. The 
 corpora striata and optic thalami are the great central 
 ganglia of the cerebral hemispheres ; their gray matter forms 
 really but a single mass in each hemisphere, and the masses 
 of the two hemispheres are joined together by the commis- 
 sura mollis of the third ventricle; in the same mariner the 
 loci nigri, in the crura cerebri, are connected by the pons 
 Tarini; the lateral gray masses of the pons Yarolii are joined 
 together, and the medulla oblongata and the spinal marrow 
 are also united in the median line by gray substance. 
 
 Thus the student will see that the white fibres, as well as 
 the gray neurine of the spinal cord, are continued through 
 the medulla oblongata, pons Yarolii, and crura cerebri, up 
 into the corpora striata and optic thalami; that although 
 the fibres may change their relative position, and the gray 
 neurine appear in different forms, yet they present an un- 
 broken continuity. 
 
 The Locus PERFORATUS MEDIUS, or PONS TARINI, Fig. 17 
 (i o), is of a gray color. It is placed between the base of the 
 brain and the posterior part of the third ventricle, and is per- 
 forated by numerous small arteries. It is very thin, and 
 easily broken through. It was called 'pons' by Tarinus, be- 
 cause it extended across from one crus cerebri to the other. 
 
 The CORPORA MAMMILLARIA, or CORPORA ALBICANTIA, Fig. 
 17 (9), are two small round bodies, white externally and gray 
 internally. The white matter is the termination of the anterior 
 cornua of the fornix on the base of the brain; the fibres of the 
 fornix do not, however, end in these bodies, but are reflected 
 upwards and backwards to the upper part of the thalami. 
 
BASE OF THE BRAIN. 79 
 
 The TUBER CINEREUM, Fig. 17 (s), is a thin mass of gray 
 matter behind the optic chiasm and in the floor of the third 
 ventricle. From the centre of this projects downwards the 
 infundibulum. This is of a reddish gray color, of a conical 
 shape, terminating below in the pituitary gland, and opening 
 above into the anterior part of the third ventricle. Its upper 
 extremity only is hollow, at least, as a general thing, in the 
 adult brain. 
 
 The PITUITARY GLAND occupies the sella turcica. It is a 
 small body, consisting of an anterior and a posterior lobe. 
 The anterior lobe is kidney- shaped, and composed of a yel- 
 lowish substance ; the posterior lobe is partly received into 
 the anterior. This body is hollow in the foetus, and com- 
 municates with the third ventricle through the infundib- 
 ulum. It is covered by a layer of the dura mater. To 
 dissect it in situ, the posterior clinoid processes should be 
 broken away. 
 
 When the optic chiasm is raised, a thin layer of gray 
 substance is seen, called the lamina cinerea. This extends 
 from the tuber cinereum behind to the corpus callosum in 
 front. Laterally, it joins on each side the perforated place 
 at the inner extremity of the fissure of Sylvius. Its upper 
 surface looks into the anterior part of the third ventricle. 
 The chiasm of the optic nerves is connected by gray matter 
 to. the lamina cinerea. 
 
 On the sides of the lamina cinerea, and crossing the 
 lateral perforated places, are seen two white fibrous bands, 
 which pass forwards to terminate in the anterior border of 
 the corpus callosum. These are named the peduncles of the 
 corpus callosum. 
 
 The Loci PERFORATI LATERALES are situated, one at the 
 commencement of each fissure of Sylvius. They are per- 
 forated by numerous small arteries which are intended, 
 mostly, for the supply of the corpora striata. 
 
 The FISSURE OF SYLVIUS, Fig. 17 (5), separates the anterior 
 and middle lobes. It serves to increase greatly the exterior 
 surface of the brain and the number of convolutions. As it 
 passes outwards, it divides into two branches, which sur- 
 round several small convolutions. These constitute the 
 island of Eeil. They correspond to the outer part of the 
 corpus striatum. 
 
80 DISSECTION OF THE HEAD AND NECK. 
 
 The LOBES of the cerebrum, Fig. 17 (3, 4, e), are six in num- 
 ber, three for each hemisphere. These are not seen on the upper 
 part of the brain, and even on the base there is no natural line 
 of separation between the posterior and middle. The middle 
 is the most prominent ; it occupies the middle fossa in the 
 base of the cranium. The posterior rests on the tentorium, 
 which separates it from the cerebellum, and at the same 
 time supports it. The anterior lobe lies on the orbital por- 
 tion of the frontal bone. It is separated from the corres- 
 ponding lobe on the opposite side by the great longitudinal 
 fissure. The two posterior lobes are separated from each 
 other by the same fissure. The extent of this fissure is 
 worthy of notice. No one can have any correct idea of the 
 number of convolutions or the extent of exterior surface 
 which each hemisphere of the cerebrum presents, without a 
 knowledge of this fissure. 
 
 The GREAT TRANSVERSE FISSURE separates the posterior 
 lobes from the cerebellum. It opens into the central exca- 
 vation in front of the pons Yarolii, passing round on each 
 side of that body, and under the crura cerebri. This fissure 
 leads into the middle cornu of each lateral ventricle, and also 
 into the third ventricle, beneath the posterior border of the 
 corpus callosum. It is in this part of the transverse fissure 
 that Bichat described a communication between the cavity of 
 the lining membrane of the third ventricle and the cavity of 
 the arachnoid, external to the brain. It is called the Canal 
 of Bichat. This anatomist described this communication as 
 being of a tubular form, and surrounding the venae Galeni. 
 There can be no doubt that it does exist in some cases. 
 
 ORIGIN OF THE CEREBRAL NERVES. 
 
 The cerebral nerves consist of nine pairs. With the excep- 
 tion of the spinal accessory, a part of the eighth pair, they 
 all arise from some part of the encephalon; they escape from 
 the cranial cavity through different foramina. There is no 
 difference between the corresponding nerves of the two sides. 
 Although each pair has a particular name, they are gener- 
 ally designated by numbers as first, second, third, &c. 
 
 The FIRST PAIR, or OLFACTORY NERVES, Fig. 17 (23), have 
 
ORIGIN OF THE CEREBRAL NERVES. 81 
 
 each three roots one arising from the fissure of Sylvius, an- 
 other from the corpus striatum, and the third from the poste- 
 rior convolutions of the anterior lobe. The last one is situated 
 between the others, and consists of gray matter. The trunk 
 formed by the union of these three roots runs forward about 
 two inches on the under surface of the anterior lobe, and then 
 swells into a bulb, which rests on the cribriform plate of the 
 ethmoid bone. The olfactory nerves are of a prismatic form, 
 each being lodged in a groove on the under surface of the 
 anterior lobe, to which it is bound by the arachnoid membrane 
 passing over it, but not around it. They are composed of 
 white and gray substance, and are softer than the other nerves. 
 The bulbs are called the olfactory lobes, and might very prop- 
 erly be considered the true origin of the olfactory nerves. 
 The filaments arise from the bulbs in two series on each side, 
 and pass through the cribriform plate of the ethmoid, the 
 outer series to the external wall, and the inner to the internal 
 wall of the nasal fossa. 
 
 The SECOND PAIR, or OPTIC, Fig. 17 (2 s), arise from the tuber- 
 cula quadrigemina, corpora geniculata, and optic thalami. The 
 part between the origin of each nerve and the chiasm is called 
 the optic tract. This is soft and flattened, and rests on the 
 crus cerebri, to which it adheres slightly. The part anterior to 
 the chiasm is round, and invested by neurilemma. The optic 
 tracts converge towards the chiasm, while the optic nerves 
 diverge as they proceed towards the orbits. The chiasm is 
 formed by a decussation of the inner fibres of each nerve, 
 while the outer fibres continue on without crossing. The 
 chiasm is connected to the tuber cinereum by a few fibres. 
 Transverse fibres have been described in this commissure. 
 As the optic nerves pass through the optic foramina, the neu- 
 rilemma is continuous with the periosteum lining the orbits ; 
 also with the sclerotic coat, as each nerve enters the ball of 
 the eye. 
 
 The THIRD PAIR, or OCULO MOTOR, Fig. 17 (3 o), arise from 
 the crura cerebri, near the pons Tarini. They can be traced 
 into the substance of the crura, to the gray matter, or loci nigri. 
 Each nerve consists of a round white cord, passes through 
 the wall of the outer part of the cavernous sinus, and en- 
 ters the orbit through the foramen sphenoidale, to be distri- 
 buted to the superior, internal, and inferior recti muscles; 
 
82 DISSECTION OF THE HEAD AND NECK. 
 
 also to the inferior oblique and the levator of the upper 
 eyelid. 
 
 The FOURTH PAIK, or PATHETIC, Fig. 17 (a i), arise from the 
 valve of Vieussens and processus eerebelli ad testes. They 
 are very small, and thread-like. Each passes through the 
 walls of the cavernous sinus, and sphenoidal foramen to go to 
 the superior oblique muscle of the eyeball. These nerves are 
 so small and delicate, that the student must be very careful 
 in tracing them, or he will either break or lose sight of them. 
 
 The FIFTH PAIR, TRIFACIAL, or TRIGEMINAL, Fig. 17 (3 2), 
 have each two roots, arising apparently from the pons Yarolii. 
 The small root consists of motor filaments, and is situated 
 above the large or sensor. The sensor portion of this nerve 
 can be traced to near the floor of the fourth ventricle, or to the 
 corpus innominatum; the motor portion is connected in its 
 origin with the fibres of the corpus pyramidale, with which it 
 is associated in function. The two roots, after leaving the pons, 
 unite to form a large cord or fasciculus, which passes beneath 
 the tentorium, perforates the dura mater, and rests on the 
 petrous bone, in its course to the middle fossa of the base 
 of the cranium, where the sensor portion expands into the 
 Gasserian ganglion. This ganglion is of a triangular shape, 
 and, when fully exposed, presents a plexiform arrangement, 
 with gray neurine intermixed. It is covered by a lamina of 
 the dura mater, which adheres closely to it. The motor fila- 
 ments pass over its under surface, and not through it. From 
 its base proceed the ophthalmic and the superior and inferior 
 maxillary branches. The first of these passes through the 
 sphenoidal foramen; the second, through the foramen ro- 
 tundurn ; and the third, through the foramen ovale. All the 
 motor filaments accompany the inferior maxillary branch. 
 The dura mater obtains filaments from the fifth pair. It 
 will be observed that this nerve resembles the spinal nerves 
 in having a motor and a sensor root, and the sensor portion 
 having a ganglion on it. 
 
 The SIXTH PAIR, or ABDUCENTES, Fig. 17 (33), arise from 
 the corpora pyramidalia, just as they enter the pons. Each 
 nerve passes through the wall of the cavernous sinus and the 
 sphenoidal foramen to reach the external rectus of the eye- 
 ball. While passing through the wall of the cavernous 
 
ORIGIN OF THE CEREBRAL NERVES. 83 
 
 sinus, it is joined by one or two filaments from the sympa- 
 thetic. They are much smaller than the third pair, but larger 
 than the fourth 
 
 The SEVENTH PAIR, Fig. 17 (34), consist each of two 
 nerves, the portio dura, or facial, and the portio mollis, or 
 auditory nerve. The portio mollis is the largest of the two, 
 and is situated behind the portio dura. It arises in the floor 
 of the fourth ventricle by the lineae transverse, and from gray 
 neurine in the corpus olivare, passes round the restiform 
 body to join the portio dura just below the crus cerebelli. 
 
 The portio dura arises from the corpus innominatum, near the 
 calamus scriptorius, and passes through the corpus restiforme; 
 it is joined by the auditory nerve, as before mentioned, and 
 both pass outwards to the meatus auclitorius internus. The 
 portio mollis goes to the labyrinth of the ear, the portio dura 
 to the muscles of the face, &c. 
 
 The EIGHTH PAIR, Fig. 17 (so), consist each of the glosso- 
 pharyngeal, the pneumogastric, and the spinal accessory of 
 Willis. The glosso-pharyngeal and pneumogastric arise on 
 each side, by quite a number of filaments, in the groove be- 
 tween the olivary and restiform bodies. The former is 
 situated a little above the latter, and is much smaller. Their 
 roots can be traced to gray matter respiratory ganglion in 
 the posterior part of the medulla oblongata, and near to the 
 floor of the fourth ventricle, upon which there are three or 
 four small protuberances corresponding to the origin of these 
 nerves. The spinal accessory arises from the side of the 
 spinal marrow, between the roots of the cervical nerves, 
 commencing as low down as the fifth or sixth cervical verte- 
 bra. The round cord or nerve which is formed by these 
 roots passes upwards behind the ligamentum denticulatum 
 to the cavity of the cranium, entering it through the foramen 
 occipitale, to join the two preceding nerves. It is very fre- 
 quently connected by filaments to the first and second cervi- 
 cal nerves. 
 
 The eighth nerve leaves the cranial cavity through the 
 jugular foramen, being separated from the .internal jugular 
 vein by a ligamentous band. 
 
 THE NINTH PAIR, or HYPOGLOSSAL, arise by several fila- 
 ments in the groove between the olivary and pyramidal bodies. 
 Each nerve corresponds in origin to the anterior roots of the 
 
84 DISSECTION OF THE HEAD AND NECK. 
 
 spinal nerves. It passes through the anterior condyloid 
 foramen, and in its cranial course usually consists of two or 
 more fasciculi. 
 
 The study of the cerebral nerves is rendered perhaps more 
 complicated to the student on account of each nerve being 
 designated by a particular name. Their origin is necessarily 
 more difficult to learn than that of the spinal nerves ; this 
 results from the gray neurine with which they are connected 
 being more scattered about and not so easily located. If we 
 were able to see clearly and 'distinctly all the gray matter 
 with which the different cerebral nerves are connected in 
 their origin, we should probably observe the same simplicity 
 in its arrangement as in that of the spinal marrow. 
 
 The student should endeavor to acquire familiarity with 
 these nerves by studying them according to their functions, 
 and in connection with the parts to which they are distri- 
 buted. If, for instance, he refers to the nervous endowment 
 of the tongue, he will at once see the necessity ^ of this organ 
 being supplied with at least three different kinds of nerves. 
 It contains muscles which must be supplied with a motor 
 nerve; and if these muscles can act independently of the 
 will, as well as under its direction, then they must be sup- 
 plied with both voluntary and involuntary motor filaments. 
 Like nearly all other parts of the body, it must have a nerve 
 of general sensibility, and, as it is the seat of taste, it must 
 have a nerve of special sensibility. He should learn to con- 
 template other organs and other parts of the body, in regard 
 to their nervous endowment, in the same manner. 
 
 The third, fourth, sixth, and ninth nerves may be regarded 
 as being associated with the motor portion of the fifth nerve, as 
 the distribution of all these motor nerves corresponds to that 
 of the sensor portion of the fifth. As the fifth is the nerve of 
 general sensibility to all parts of the face, superficial as well 
 as deep seated, so would it then also be the nerve of volun- 
 tary motion to all the muscles of the same parts. This would 
 leave only the four nerves of special sensibility and the por- 
 tio dura, an involuntary motor nerve, to be distributed to the 
 head ; the pneumogastric and spinal accessory going to sup- 
 ply other parts. The following table will exhibit to the 
 student, at a glance, the functional divisions of the cerebral 
 nerves : 
 
ARTEKIES OF THE BRAIN. 85 
 
 fist. Olfactory. 
 
 SPEC.AL SENSATION . . . 
 
 [8th. Gustatory. 
 
 COMMON S 
 
 f 3d. Oculo-motor. 
 
 4th. Pathetic. 
 
 VOLUNTARY MOTION . . . \ 5th. Trigerainal. 
 
 | 6th. Abducens 
 
 [9th. Hypoglossal. 
 
 ARTERIES OF THE BRAIN. 
 
 The arteries of the brain are derived from the internal 
 carotid and the vertebral. Each internal carotid gives off at 
 the base of the brain the anterior and middle cerebral, and 
 the posterior communicating branch. 
 
 The ANTERIOR CEREBRAL ARTERY, Fig. 18 (i 3), is directed 
 forwards and inwards to the fissure in front of the chiasm of 
 the optic nerves. Just before it enters the fissure which separ- 
 ates the anterior lobes of the cerebrum, it is connected to the 
 anterior cerebral artery of the opposite side by a transverse 
 anastomosing branch named the Anterior Communicating Ar- 
 tery, Fig. 18 (14). This artery is usually not more than one 
 or two lines in length. It completes the circle of Willis 
 anteriorly. The anterior cerebral arteries then enter the 
 fissure together, and pass upwards over the anterior extremity 
 of the corpus callosum, and backwards on its superior sur- 
 face to its posterior extremity. They are sometimes called the 
 arteries of the corpus callosum, where they rest on that body. 
 
 The MIDDLE CEREBRAL ARTERY, Fig. 18 (12), passes out- 
 wards and backwards to the fissure of Sylvius, in which it 
 gives off a great number of branches. To trace this artery 
 in its course, the anterior lobe must be separated from the 
 middle, so as to expose the whole of the fissure of Sylvius. 
 
 The POSTERIOR COMMUNICATING ARTERY, Fig. 18(9), passes 
 8 
 
86 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 backwards to join the posterior cerebral artery, which is a 
 branch of the vertebral. It varies greatly in size. 
 
 The VERTEBRAL ARTERIES, Fig. 18 (i), enter the cavity of 
 the cranium through the foramen occipitale, and coalesce just 
 
 Fig. 18. 
 
 1. The vertebral arteries. 2. The two anterior spinal branches. 3. One of the 
 posterior spinal arteries. 4. The posterior tucningeal artery. 5. The inferior cere- 
 bellar. 6. The basilar artery. 7. The superior cerebellar. 8. The posterior cere- 
 bral. 9. The posterior communicating. 10. The internal carotid. 11. The oph- 
 thalmic. 12. The middle cerebral. 13. The anterior cerebral. 14. The anterior 
 communicating. 
 
 behind the pons Yarolii to form the BASILAR ARTERY, Fig. 
 18 (e). This artery extends to the anterior border of the 
 pons, where it divides into the posterior cerebral arteries. 
 The cerebellar arteries are given off, the inferior from the 
 vertebral, and the superior from the basilar. 
 
 The POSTERIOR CEREBRAL ARTERY, Fig. 18 (s), on each side 
 is directed outwards and backwards round the crus cerebri 
 
ARTERIES OF THE BRAIN". 87 
 
 to the great transverse fissure, and to the under surface of 
 the posterior lobe of the brain. A short distance from its 
 origin it is joined by the posterior communicating branch of 
 the internal carotid. 
 
 The SUPERIOR CEREBELLAR ARTERY, Fig. 18 (7), winds 
 round the crus cerebri to the superior surface of the cerebel- 
 lum. It is separated from the preceding artery by the third 
 nerve, and accompanies for some distance the fourth nerve. 
 It sends a small branch into the meatus auditorius internus. 
 
 The INFERIOR CEREBELLAR ARTERY, Fig. 18 (5), arises 
 from the vertebral, and passes round the medulla oblongata 
 to the under surface of the cerebellum. It passes between 
 the roots of the ninth nerve and in front of the glosso- 
 pharyngeal and pneumogastric. 
 
 It will be observed that a free anastomosis exists between 
 the arteries at the base of the brain. The internal carotids 
 are connected together by the anterior communicating artery, 
 while they are both connected to the basilar by the two pos- 
 terior communicating arteries. It is by means of these 
 communicating arteries that the circle of Willis is formed. 
 It will also be noticed that no arterial branch of any con- 
 siderable size penetrates the substance of the brain. 
 
 The following parts are to be examined in the base of the 
 cranium after the brain has been removed. 
 
 The DURA MATER. This membrane will be found to 
 adhere very closely to the greater part of the base of the 
 cranium. It sends out prolongations through the various 
 apertures to be continuous with the periosteum, and to 
 form sheaths for the nerves. It is firmly attached to the 
 margin of the foramen occipitale, but does not adhere to the 
 walls of the spinal canal. Its internal surface is everywhere 
 lined by the arachnoid. The falx cerebri was examined be- 
 fore the removal of the brain, and the tentorium was neces- 
 sarily cut in that operation. The student can, however, 
 replace it, and retain it in situ with a few stitches, so as to 
 get a very good view of it and its connections. 
 
 The TENTORIUM, Fig. 9 (s), forms a horizontal septum between 
 the spaces occupied by the cerebellum and posterior lobes of 
 the cerebrum. Its convex border corresponds to the transverse 
 ridge on the inner surface of the occipital bone, extending 
 
88 DISSECTION OF THE HEAD AND NECK. 
 
 forwards to the base of the petrous portion of the temporal 
 bone. Anteriorly it is attached to the petrous bone, and to 
 the clinoid processes of the sphenoid. Its centre is some- 
 what raised, so as to form an arch, and has attached to its 
 upper surface in the median line the posterior extremity 
 of the falx cerebri. Its attachments are such that it is kept 
 in a state of tension, and is consequently well adapted to 
 support the posterior lobes of the cerebrum and to protect 
 the cerebellum. A large oval opening exists in it anteriorly, 
 which establishes a communication between the compartment 
 of the cerebrum and that of the cerebellum and the spinal 
 canal. 
 
 The FALX CEREBELLI is a process of the dura mater, 
 which projects into the fissure between the hemispheres of 
 the cerebellum. Its upper and broadest extremity is at- 
 tached to the under surface of the tentorium ; its lower ex- 
 tremity divides into two slips to embrace the foramen occipi- 
 tale. Its posterior border is attached to the lower part of the 
 vertical ridge of the occipital bone. 
 
 The SINUSES, Fig. 8 and Fig. 19, of the dura mater are canals 
 for the transmission of venous blood. They are veins which 
 derive the fibrous layer of their coats from the dura mater ; 
 in form they differ from veins in other parts of the body, but 
 not in structure. They have no true valves. Some of the 
 small ones vary in number, but there are usually fourteen or 
 fifteen altogether. Some of these are single and found in the 
 median line, and some exist in pairs. 
 
 The superior longitudinal sinus has already been described; 
 also the inferior longitudinal sinus. 
 
 The STRAIGHT SINUS is situated between the laminae of the 
 dura mater at the junction of the falx cerebri and tentorium. 
 It is formed principally by the venae Galeni and inferior 
 longitudinal sinus, and terminates in the torcular Herophili, 
 sometimes by two orifices. 
 
 The OCCIPITAL SINUS is in the attached border of the falx 
 cerebelli. Sometimes there are two of them. It collects the 
 blood from the contiguous parts, and conveys it into the 
 torcular. 
 
 The LATERAL SINUSES commence at the torcular Herophili 
 and extend to the jugular foramina, occupying a groove on 
 each side in the occipital, parietal, and temporal bones. The 
 
SINUSES OF THE DURA MATER. 
 
 89 
 
 right one is usually larger than the left. They are situated, in 
 the horizontal part of their course, along the convex or attach- 
 ed border of the tentorium. They are the largest of all the 
 sinuses in the dura mater, as they receive the blood from all 
 the rest, to empty it into the internal jugular veins. They 
 increase in size as they proceed towards the jugular foramina, 
 to receive the contents of the petrosal sinuses, the mastoid, 
 and also the inferior cerebral and cerebellar veins. The 
 inferior or curved portion of each is deeply imbedded in the 
 bone, and when cut across presents an oval figure, while the 
 horizontal portion projects between two layers of the ten- 
 torium, and is of a triangular shape. 
 
 The CAVERNOUS SINUSES are situated one on each side of the 
 sella turcica. They are of an irregular shape, and have a reti- 
 culated structure internally. Each receives the ophthalmic 
 vein of the corresponding side. 
 The third and fourth nerves, Fi S- 19 - 
 
 and the ophthalmic branch 
 of the fifth, pass through its 
 outer wall ; the internal ca- 
 rotid artery, and the sixth 
 nerve, pass between its fibrous 
 covering and the serous mem- 
 brane which lines it. The 
 two cavernous sinuses are 
 connected by the circular 
 sinus. The petrosal sinuses 
 establish a communication be- 
 tween them and the lateral 
 sinuses. 
 
 The CIRCULAR SINUS sur- 
 rounds the pituitary gland, 
 from which it receives several 
 small veins. 
 
 . The circular sinus. 6. The cavern- 
 ous sinus, c. The ophthalmic vein. d. 
 The superior petrosal sinus, e. The in- 
 ferior petrosal sinus. /. The transverse 
 sinus, g. The occipital sinus, h. The 
 lateral sinus on the right side. t. The 
 torcular Herophili. 
 
 The TRANSVERSE SINUS lies 
 across the cuneiform process 
 of the occipital bone. Some- 
 times there are two of them. 
 
 The SUPERIOR PETROSAL SINUS occupies a groove on the 
 upper part of the petrous portion of the temporal bone. 
 
 The INFERIOR PETROSAL SINUS of each side is lodged in a 
 
 8* 
 
90 DISSECTION OF THE HEAD AND NECK. 
 
 groove along the suture, between the petrous and occipital 
 bones. 
 
 It will be observed that the sinuses at the base of the cra- 
 nium communicate freely with each other, so as to form a 
 sort of venous network. 
 
 AETEKIES OF THE DURA MATER. 
 
 The arteries of the dura mater are derived from several 
 sources. , 
 
 The ANTERIOR MENINGEAL are branches of the ethmoid al, 
 and enter the cavity of the cranium through the ethmoidal 
 foramina. 
 
 The MIDDLE MENINGEAL is the largest of all the arteries 
 of the dura mater. It passes through the foramen spinosum 
 of the great wing of the sphenoid bone. Its terminal branches 
 were seen when the calvaria was removed. It ramifies 
 between the bone and the dura mater, presenting an arbores- 
 cent appearance. The grooves or furrows in the bone, which 
 are occupied by the branches of this artery, vary very much 
 in depth. In trephining, the relations of the middle menin- 
 geal artery to the osseous walls of the cranium are important 
 to be recollected. The situation of the principal trunk is 
 indicated externally by a line extending from near the centre 
 of the zygoma directly upwards. 
 
 The POSTERIOR MENINGEAL ARTERY is a branch of the 
 vertebral. It arises nearly opposite the foramen magnum. 
 
 Besides these, the dura mater gets a branch from the inter- 
 nal maxillary, through the foramen ovale, which is sometimes 
 called the meningea parva; another branch from the ascend- 
 ing pharyngeal, through the foramen lacerum medius ; one 
 from the internal carotid ; and a fourth from the occipital, 
 through the foramen lacerum posterius. 
 
 The nerves of the dura mater are derived principally from 
 the .fifth pair. 
 
APPENDAGES OF THE EYE WITHIN THE ORBIT. 91 
 
 SECT. VI. DISSECTION OF THE APPENDAGES OF THE EYE 
 WITHIN THE ORBIT. 
 
 To dissect the appendages of the eye within the orbit, the 
 orbital plate of the frontal bone must first be cut away. This 
 can easily be done, after the calvaria has been removed, 
 with a small sharp chisel or saw. The former is preferable, 
 because it can be accommodated to the inequalities of the 
 surface which is to be cut. The lesser wing of the sphenoid 
 may also be removed with the orbital plate, care being taken 
 not to destroy the optic foramen, nor disturb the contents of 
 the sphenoidal fissure. Before removing the orbital ridge, 
 the tendinous loop for the passage of the tendon of the 
 superior oblique muscle should be examined, or the inner 
 extremity of the ridge to which the loop is attached may be 
 left. In removing the orbital plate, the periosteum which 
 covers its under surface, and to which it is loosely connected, 
 should be preserved. 
 
 Before proceeding to examine the contents of the orbit, 
 the student will do well to obtain some idea of what they 
 consist, and in what part of the orbit each is to be found. 
 The dissection must also be conducted slowly and cautiously, 
 so as not to destroy any of the minuter structures involved. 
 The upper plane of the orbit is occupied on the nasal side 
 by the superior oblique muscle, with the pathetic nerve 
 resting on it ; in the central portion by the frontal nerve, and 
 immediately below it, the levator palpebra3 superioris; and 
 in the outer part by the lachrymal nerve, and beneath it the 
 upper margin of the external rectus, on the outer side of which 
 lies the lachrymal gland. 
 
 The FRONTAL NERVE, Fig. 20, enters the orbit above the 
 muscles, and proceeds along its central portion, close to the 
 periosteum, towards the supra-orbital foramen, where it di- 
 vides into the supra- orbital and frontal branches. The former 
 sends filaments to the upper eyelid, and then passes through 
 the supra-orbital foramen to the forehead ; the latter gives off 
 filaments to the eyelid, also one to the frontal sinus, and one 
 which anastomoses with the external nasal; its terminal 
 branches are distributed on the forehead. 
 
92 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 The LEVATOR PALPEBR^I MUSCLE, Fig. 23 (4), arises from 
 
 the roof of the orbit in front of 
 the optic foramen. It widens 
 as it extends forwards, and is 
 inserted by a broad tendon 
 into the upper margin of the 
 superior tarsal cartilage. 
 
 The SUPERIOR OBLIQUE 
 MUSCLE, Fig. 23 (5), arises 
 from the inner part of the op- 
 tic foramen, passes along the 
 inner and upper part of the 
 orbit to the cartilaginous pul- 
 ley, through which its tendon 
 passes to be reflected down- 
 wards, backwards, and out- 
 wards to the ball of the eye. 
 The reflected portion of this 
 muscle must be left for the 
 present. 
 
 The FOURTH NERVE, or the 
 PATHETIC, Fig. 20 ( 4 ), enters 
 the orbit above, and on the 
 inner side of the frontal, which it leaves in the posterior part 
 of the orbit, passing inwards to the superior oblique muscle, 
 which it penetrates by several filaments on the orbital side. 
 
 The LACHRYMAL NERVE, Fig. 37 (10), enters the orbit a 
 little to the outside of, and below the frontal nerve, and above 
 the muscles, runs along the upper border of the external 
 rectus to the lachrymal gland, to which it sends filaments ; 
 after perforating or passing beneath the gland, it divides into 
 palpebral branches. One of these anastomoses with a branch 
 of the facial, one goes to the integument upon the forehead, 
 and one or two filaments pass downwards to join the second 
 division of the fifth pair. 
 
 These parts may now be divided in the anterior portion of 
 the orbit, and reflected back. As the levator palpebrae is 
 turned back, a branch of the third nerve, or motor oculi, will 
 be seen entering it on its under surface. The nerves above 
 described should all be preserved for the purpose of tracing 
 them through the cavernous sinus. 
 
 THE NERVES IN THE ORBIT ABOVE THE 
 MUSCLES, BROUGHT INTO VIEW BY RE- 
 MOVING THE ROOF OP THE ORBIT AND 
 
 THE PERIOSTEUM. 1. Fifth nerve. 2. 
 Ophthalmic branch of same nerve. 3. 
 Third nerve. 4. Fourth nerve. 5. Optic 
 nerve. 6. Sixth nerve, a. Internal ca- 
 rotid artery. 
 
APPENDAGES OF THE EYE WITHIN THE ORBIT. 93 
 
 Fig. 21. 
 
 The SUPERIOR RECTUS MUSCLE, Fig. 23 (9), is now seen in 
 the central part of the orbit. It arises from the upper and 
 outer part of the optic foramen, and passes forwards to be 
 inserted into the sclerotic coat of the eyeball, near its junction 
 with the cornea. This is to be divided near its insertion, and 
 turned back, observing at the same time the branch of the 
 motor oculi nerve, which penetrates its under surface. Be- 
 neath the superior rectus, and between the external and in- 
 ternal recti muscles, is the most intricate part of the anatomy 
 of the orbit. The areolar and adipose tissue found here must 
 be gradually and cautiously removed. 
 
 The NASAL NERVE, Fig. 21, with the ophthalmic artery and 
 vein, crosses the optic nerve 
 from without inwards. As 
 this nerve enters the orbit 
 between the two heads of the 
 rectus externus, it usually 
 sends a small twig to the 
 lenticular ganglion, and just 
 as it passes over the optic 
 nerve, gives off three or four 
 ciliary branches, which ac- 
 company that nerve on its 
 inner side to perforate the 
 sclerotic coat. The nasal 
 nerve then continues its 
 course to the inner part of 
 the orbit, and forwards as 
 far as the anterior ethrnoidal 
 foramen, where it divides 
 into an external and inter- 
 nal nasal branch. The m- 
 ternal nasal passes through 
 this foramen, and after run- 
 
 i , -1 . , ,-j i*. -LiiiLTUiu uiervguiu IUHM;JU. v, A GUI- 
 
 nmg a Short distance On the poral muscle, c. Cut surface of bone. d. 
 
 Cribriform plate of the eth- Elevator of the eyelid and upper rectus 
 
 T -i .-} luusclo. c. C&rotid 3,rt6rv. Untie 
 
 moid bone, enters the nose nerve> 2 . Fifth nerve. 3. Ophthalmic 
 
 through a Small foramen at nerve. 4. Third nerve. 5. Sixth nerve. 
 
 the side of the crista galli, 
 
 then continues in a groove on the inner surface of the nasal 
 
 bone to its lower border, where it leaves the nasal cavity 
 
 THE DEEP NERVES OF THE ORBIT SEEN 
 FROM ABOVE BY REMOVING THE BONE AND 
 DIVIDING THE ELEVATOR OF THE UPPER 
 EYELID AND THE UPPER RECTUS MUSCLE. 
 Internal pterygoid muscle, b. Tern- 
 
94 DISSECTION OF THE HEAD AND NECK. 
 
 to be distributed to the integument covering the ala of the 
 nose. 
 
 The external nasal, or infra-trochl&xr, goes to the anterior 
 and inner part of the orbit, beneath the tendon of the supe- 
 rior oblique, where it divides into filaments to supply the 
 integument of the upper part and side of the nose, the upper 
 eyelid, and lachrymal sac. 
 
 The LENTICULAR G-ANGLION, Fig. 22 (e), is a small reddish 
 body, situated between the optic nerve and external rectus 
 muscle, about half an inch behind the ball of the eye. Its 
 size and shape vary in different subjects. Behind, it receives 
 a filament from the nasal and the lower division of the motor 
 oculi, and is usually connected with the sympathetic by a 
 branch from the cavernous sinus. Anteriorly it sends off 
 eight or ten ciliary branches, which pass along the outer and 
 under part of the optic nerve to perforate the sclerotic coat. 
 This small ganglion may readily be found by tracing one of 
 the ciliary nerves backwards to its origin. 
 
 The OPHTHALMIC ARTERY, a branch of the internal carotid, 
 arises near the anterior clinoid process, and enters the orbit 
 through the optic foramen, behind and exterior to the optic 
 nerve, and crosses it to reach the nasal nerve, which it accom- 
 panies to the inner and anterior part of the orbit, where it 
 divides into its terminating branches. The following are 
 branches of this artery : 
 
 The lachrymal branch arises between the superior and ex- 
 ternal recti muscles, but soon joins the lachrymal nerve, and 
 accompanies it to the lachrymal gland, which it supplies. It 
 also sends branches to the upper eyelid, to the conjunctiva, 
 and one which perforates the malar bone to anastomose with 
 the deep temporal arteries. It sometimes anastomoses with 
 the middle meningeal. 
 
 The central artery of the retina penetrates the optic nerve 
 about half an inch behind the eyeball, which it enters 
 through the porus opticus, to be distributed to the retina 
 and hyaloid membrane (Fig. 21). 
 
 The supra-orbital arises beneath the superior rectus, and 
 passes upwards and forwards on the inner side of this muscle 
 and the levator palpebrse, joins the supra-orbital nerve, and, 
 with it, goes to the forehead, sending a small branch to the 
 frontal bone. 
 
APPENDAGES OF THE EYE WITHIN THE ORBIT. 95 
 
 The ciliary arteries consist of three sets ; the anterior, which 
 are irregular in their origin, perforate the sclerotic coat about 
 two lines behind the margin of the cornea; the long and 
 
 Fig. 22. 
 
 A VIEW OF THE THIRD, FOURTH, AND SIXTH PAIRS OP NERVES. 1. Ball of the 
 eye, the rectus extern us muscle being cut and hanging down from, its origin. 2. 
 The superior maxilla. 3. The third pair, or motor oculi, distributed to all the mus- 
 cles of the eye except the superior oblique and external rectus. 4. The fourth pair, 
 or pathetic, going to the superior oblique muscle, o. Ono of the branches of the 
 fifth. 6. The sixth pair, or motor externus, distributed to the external rectus mus- 
 cle. 7. Spheno-palatine ganglion and branches. 8. Ciliary nerves from the len- 
 ticular ganglion, the short root of which is seen to connect it with the third pair. 
 
 short posterior arise a little distance behind the ball of the 
 eye ; the short, ten or fifteen in number, accompany the ciliary 
 nerves; the two long ones perforate the sclerotic coat, one on 
 either side of the optic nerve, and a little farther from it than 
 the short. 
 
 The muscular branches are divided into the superior, which 
 go to the superior rectus, oblique, and levator palpebrae ; and 
 the inferior, which are distributed to the other recti muscles, 
 and inferior oblique, and from which are derived some of the 
 anterior ciliary arteries. 
 
 The ethmoidal branches pass through the anterior and poste- 
 rior ethmoidal foramina, and give branches to the dura mater 
 and upper part of the nasal fossae. 
 
 There are two palpebral branches; the superior, which enters 
 the upper lid near the inner angle and anastomoses with the 
 
96 DISSECTION OF THE HEAD AND NECK. 
 
 lachrymal ; the inferior, which descends behind the tendon 
 of the orbicularis to the lower lid, and anastomoses with the 
 infra-orbital. 
 
 The nasal artery runs over the tendon of the orbicularis to 
 the integument covering the side of the nose, and anasto- 
 moses with the facial. The frontal goes to the muscles and 
 integument of the forehead. 
 
 The OPTIC NERVE enters the orbit through the optic fora- 
 men, and proceeds to the ball of the eye, which it enters just 
 inside of its axis. As it passes through the optic foramen, 
 it receives an investment from the dura mater, which leaves 
 it again to become continuous with the sclerotic coat. 
 
 The OPHTHALMIC VEIN, Fig. 19, c, is formed by branches 
 corresponding to the arteries in the orbit. It leaves the" orbit 
 between the two heads of the rectus externus, passing through 
 the sphenoidal fissure to terminate in the cavernous sinus. 
 At the inner and anterior part of the orbit, it communicates 
 with the frontal and facial veins. 
 
 The vessels and nerves which enter the ball of the eye, and 
 which have been examined, may now be detached and turned 
 backwards, to facilitate the dissection of the parts in the lower 
 portion of the orbit. 
 
 The INTERNAL KECTUS MUSCLE, Fig. 23 (10), arises from 
 the margin of the optic foramen, and passes along the inner 
 part of the orbit, to be inserted into the sclerotica just behind 
 the cornea. It is partially separated from the eyeball by 
 the inferior oblique. A branch of the motor oculi nerve 
 enters its ocular surface. 
 
 The EXTERNAL RECTUS, Fig. 23 (i i), arises by two heads 
 connected by a tendinous arch, beneath which the motor 
 oculi and nasal branch of the fifth enter the orbit. It occu- 
 pies the outer part of the orbit, and is inserted into the scle- 
 rotica in the same manner as the other recti. This muscle 
 is supplied by the sixth nerve, or abducens, which enters the 
 orbit between the motor oculi and ophthalmic vein, and pene- 
 trates the ocular surface of the muscle by several filaments. 
 
 The INFERIOR KECTUS, Fig. 23 (i 3), arises in common with 
 the internal rectus and lower head of the external rectus, 
 and extends along the lower part of the orbit to the eyeball, 
 
APPENDAGES OF THE EYE WITHIN THE DEBIT. 97 
 
 into which it is inserted like the other recti. It receives a 
 branch from the motor oculi, which enters its ocular surface. 
 
 Fig. 23. 
 
 A VIEW OF THE MUSCLES OF THE EYEBALL, TAKEN FROM THE OUTER SIDE OF THE 
 RIGHT ORBIT. 1. A small fragment of the sphenoid bone around the entrance of 
 the optic nerve into the orbit. 2. The optic nerve. 3. The globe of the eye. 4. 
 The levator palpebrse muscle. 5. The superior oblique muscle. 6. Its cartilaginous 
 pulley. 7. Its reflected tendon. 8. The inferior oblique muscle ; a piece of its bony 
 origin is broken off. 9. The superior rectus muscle. 10. The internal rectus, almost 
 concealed by the optic nerve. 11 . Part of the external rectus, showing its two beads. 
 12. The extremity of the external rectus at its insertion, the intermediate portion 
 of the muscle having been removed. 13. The inferior rectus muscle. 14. The scle- 
 rotic coat. 
 
 The internal and external recti may now be divided within 
 a short distance of their insertion, and turned back with the 
 nerves supplying them, thus bringing into view the inferior 
 oblique, with the nerve distributed to it. 
 
 The INFEKIOR OBLIQUE MUSCLE, fig. 23 (e), arises from the 
 inner and anterior part of the floor of the orbit, crosses the 
 inferior rectus, between it and the periosteum, and continues 
 in a direction obliquely outwards and upwards, between 
 the external rectus and the eyeball, to be inserted into the 
 sclerotica near the insertion of the superior oblique. The 
 nerve to the inferior oblique is the largest branch of the 
 motor oculi; it runs along the exterior border of the infe- 
 rior rectus, and penetrates the muscle at right angles. This 
 branch of the motor oculi is connected by a filament to the 
 lenticular ganglion. 
 
 Besides the nerves already mentioned, a branch from the 
 superior maxillary division of the fifth pair enters the orbit 
 through the posterior part of the spheno-maxillary fissure, 
 and divides into the malar and temporal branches. This 
 nerve is situated in the lower and outer part of the orbit. 
 The malar portion passes through the malar bone, and supplies, 
 
98 DISSECTION" OF THE HEAD AND NECK. 
 
 in part, the orbicularis palpebrarum, anastomosing with the 
 facial nerve. The temporal portion, after receiving a branch 
 from the lachrymal nerve, passes through the malar bone to 
 the temporal fossa, in which it ascends some distance, then 
 perforates the temporal aponeurosis, and is distributed to the 
 integument. It anastomoses with the facial in the temporal 
 fossa. 
 
 The eyeball may now be removed from the orbit, and the 
 attachment of the ocular muscles to the sclerotic coat ex- 
 amined. For this purpose, the ball should be distended with 
 wax or some other material of sufficient firmness to preserve 
 its shape. 
 
 The insertion of the oblique muscles should be studied with 
 reference to the axis of the ball, and the manner in which 
 they would affect the eyeball when acting alone or in con- 
 junction with the recti muscles. They would seem to be 
 capable, of resisting the tendency of the recti to sink the eye- 
 ball deeper into the orbit, and, at the same time, of steadying 
 it when one or two of the recti act separately, as in turning 
 the eye in a particular direction. They are evidently in- 
 tended to act in conjunction with the recti, rather than by 
 themselves. 
 
 The contents of the sphenoidal fissure, the optic foramen, 
 and cavernous sin as should now be examined. To do this 
 the lesser wing of the sphenoid, with its attachments to the 
 body of the bone, must be removed, if not already done. 
 
 The optic foramen is occupied by the optic nerve, with the 
 ophthalmic artery, which lies below and outside of the 
 nerve. 
 
 The sphenoidal fissure has passing through it the ophthalmic 
 vein, the third, fourth, first branch of the fifth, and sixth 
 nerves, and a filament from the lenticular ganglion, to the 
 carotid plexus of the sympathetic. These are arranged as fol- 
 lows : The fourth, the frontal, the superior division of the 
 third and the lachrymal nerves, occupy the upper part of the 
 fissure, and are situated, in relation to each other, as enume- 
 rated, beginning with the fourth on the inner side. Immedi- 
 ately below these are the nasal, and the lower division of the 
 third, with the sixth beneath them. The ophthalmic vein or 
 veins, occupy the lowest part of the fissure. The nasal, third, 
 and sixth nerves as they enter the orbit, pass between the 
 two heads of the rectus externus. 
 
THE EYEBALL. 99 
 
 The cavernous sinus, Fig. 24, contains the same nerves as 
 the sphenoidal fissure, before any division has taken place. 
 They are situated, except the sixth, between the serous and 
 fibrous layers of its upper wall, the third being on the inner 
 side, and the ophthalmic on the outer, with the fourth in the 
 
 Fig. 24. 
 
 i 7 
 
 A TRANSVERSE SECTION OF THE CAVERNOUS SINUS OP THE RIGHT SIDE. 1. The 
 dura mater, splitting to inclose the vessels and nerves. 2. The internal carotid 
 artery. 3. The sixth nerve, receiving a branch from the sympathetic. 4. The 
 cavernous sinus. 5. The third nerve. 6. The fourth nerve. 7. The ophthalmic 
 division of the fifth nerve. 
 
 middle. Between the laminae of the lower part of the sinus is 
 the internal carotid artery, with the sixth nerve lying at the 
 outside of it. The sixth nerve is here connected with one 
 or more filaments from the carotid plexus. Filaments may 
 also be traced from this plexus to the other orbital nerves. 
 The intercommunicating filaments which exist between these 
 nerves in the cavernous sinus constitute the orbital plexus. 
 
 SECT. VII. THE EYEBALL. 
 
 The eyeball is the special organ of vision. Its internal 
 parts are very delicate and easily destroyed; hence the dis- 
 section of it requires careful manipulation. The student 
 should not, however, be discouraged if he fails in his first 
 attempt; a little perseverance will give him the dexterity 
 requisite to expose satisfactorily its minutest parts. The eyes 
 o? some of the lower animals may be procured for dissection. 
 These can be obtained in a fresh condition, and, as they are 
 larger, can be dissected with greater facility than the human 
 eye. It will be well to have several on hand at the same 
 time, as the beginner, especially, may expect to destroy quite 
 a number before -he- succeeds -in a -complete dissection. Care 
 must be take A 'tlgtai; they 'are' not; mjlifce'l in' removing them 
 from the orbit. 
 
100 DISSECTION OF THE HEAD AND NECK. 
 
 The muscles, areolar tissue, and mucous membrane should 
 be dissected off from the external surface. This can be done 
 best with scissors. 
 
 The eyeball is not a perfect sphere, but seems to consist 
 of segments of two globes of different sizes; the posterior 
 segment forms about four-fifths of the exterior surface of the 
 ball, and the anterior about one-fifth. The antero-posterior 
 diameter of the human eye is about eleven lines, and the 
 transverse about ten. 
 
 The external tunic constitutes the framework of the eye ; 
 gives it form; affords attachments for muscles; allows the 
 passage of rays of light to its interior; transmits vessels 
 and nerves, and serves to protect its internal, delicate struc- 
 tures. This tunic consists of two parts ; the cornea, which 
 corresponds to the anterior segment, and the sclerotica, which 
 corresponds to the posterior segment. 
 
 The SCLEROTICA, Fig. 25 (V), is opaque, of a pearly white ap- 
 pearance, and perforated by numerous foramina, which should 
 be observed before commencing the dissection of the ball. Be- 
 hind, and a little to the inner side of its axis, is the entrance of 
 the optic nerve, which is funnel-shaped from without inwards. 
 This nerve does not pass through a single large opening, but 
 through small apertures, and in separate filaments. The term 
 lamina cribrosa has been applied to the structure thus per- 
 forated. In the centre of this is the porus options for the 
 transmission of the arteria centralis retince, Fig. 28 (2). A short 
 distance from, and around the entrance of the optic nerve are 
 quite a number of small foramina, Fig. 26, for the passage of 
 the ciliary nerves and the posterior long and short ciliary 
 arteries; the long ciliary arteries enter, one on each side of 
 the optic nerve. Just behind the middle of the eye are 
 usually four or five apertures for the exit of the venous 
 trunks formed by the vasa vorticosa. Near the anterior 
 margin of the sclerotica are several other small foramina for 
 the transmission of the short anterior ciliary arteries. 
 
 As the optic nerve perforates the sclerotica on the internal 
 side of the axis of the eye, it is considerably nearer to the 
 inner than to the outer part of its anterior border. One of 
 the eyes provided for dissection should be divided vertically 
 through its axis, < and qverythiag .removed ."but >the cornea 
 and sclerotica. i<he "maox- surface,,, the^ -.thickness-, the struc- 
 ture, and the connection of the sclerotica with the cornea can 
 
THE EYEBALL. 
 
 101 
 
 now be examined. The inner surface is smooth., being lined 
 with a serous membrane, the tunica serosa, and is usually of a 
 
 Fig. 25. 
 
 A LONGITUDINAL SECTION OP THE GLOBE OF THE EYE. 1. The sclerotic coat. 
 2. The cornea. 3. The choroid coat. 4. The ciliary ligament. 5. The ciliary 
 processes. 6. The iris. 7. The pupil. 8. The retina. 9. The canal of Petit, 
 which encircles the lens. 10. The anterior chamber of the eye, containing aque- 
 ous humor. 11. The posterior chamber. 12. The lens inclosed in its proper 
 capsule. 13. The vitreous humor inclosed in the hyaloid membrane. 14. A tubu- 
 lar sheath of the hyaloid membrane, or canal of Cloquet. 15. The neurileinma of 
 the optic nerve. 16. The arteria centralis retinae. 
 
 darkish appearance ; more so anteriorly, on account of pig- 
 mentary cells contained in its structure. It diminishes in 
 thickness from behind forwards to its anterior border. In 
 children of strumous diathesis, the anterior part of it, which is 
 known as the white of the eye, is sometimes so thin and 
 translucent that it presents a bluish tint from the choroid 
 coat showing through it. It is of a dense fibrous structure, 
 consisting of white and yellow elastic tissue ; the fibres run- 
 ning in every direction. Its great strength may be tested by 
 an attempt to tear it in any direction. This unyielding 
 character is the cause of great pain in some diseases of the eye. 
 Its connection with the cornea is very firm, requiring 
 maceration for some time to effect a separation. The margin 
 of the sclerotica is beveled from within outwards, so as to 
 overlap the margin of the cornea, which is beveled in the op- 
 posite direction. This overlapping reaches a little further 
 above and below than at either side, thus causing an appa- 
 rent difference in the transverse and vertical diameters of the 
 cornea. The external surface of the sclerotica is in relation 
 
 9* 
 
102 DISSECTION OF THE HEAD AND NECK. 
 
 anteriorly with the conjunctiva, with which it is connected by 
 loose areolar tissue, except near the cornea; just behind this, 
 with the tendons of the muscles of the eye ; and more posterior- 
 ly, with fat and areolar tissue ; its internal surface is in appo- 
 sition with the choroid coat and ciliary ligament. It is con- 
 nected by means of the neurilemma of the optic nerve, with 
 the dura mater, and the periosteum of the orbit. 
 
 THE CORNEA, Fig. 25 (2), is perfectly smooth and transpa- 
 rent, being adapted to the transmission of rays of light. It 
 consists of the segment of a sphere of about seven lines in 
 diameter. 
 
 The two surfaces of the cornea are not exactly parallel, it 
 being thicker in the centre than at the margin; hence it acts 
 to some extent as a lens. It is composed of the four following 
 layers, going from without inwards : The conjunctiva, the pro- 
 per cornea, the elastic cornea, and the aqueous membrane. 
 The continuation of the conjunctiva over the cornea is proved by 
 maceration, by disease, and by the case of animals which shed 
 their skins. This layer is composed of cells which contain a 
 limpid fluid. The proper cornea consists of from sixty to 
 seventy lamellae, connected by a delicate areolar tissue, which 
 contains a vapor or fluid. When the lamella are pressed 
 together and this fluid displaced, the cornea is rendered 
 opaque until the pressure is removed, and the fluid restored 
 to its natural condition. The proper cornea is blended with 
 the sclerotica. The elastic cornea is a thin, transparent lamina, 
 lining the concave surface of the proper cornea. It is not 
 made opaque by maceration or by boiling ; the shape of the 
 cornea is said to depend on it. Its margin projects in be- 
 tween the sclerotica and ciliary ligament. The aqueous layer 
 is a portion of the thin delicate membrane, which lines the 
 chambers of the eye, and secretes the aqueous humor. 
 
 After death the cornea becomes flaccid on account of the 
 aqueous humor transuding through it. A molecular change 
 in the fluid between the lamellae of the proper cornea has 
 been supposed to be the cause of the dimness of the eye 
 which occurs in the moribund state. The structure of the 
 proper cornea is regarded as a modified form of white fibrous 
 tissue ; that of the elastic cornea is not well understood. The 
 cornea is very sparingly supplied with bloodvessels and 
 nerves ; wounds of it, however, generally heal by the first in- 
 
THE EYEBALL. 103 
 
 tention. Its liability to disease and injury renders it an ob- 
 ject worthy of special attention to the student. 
 
 Having examined the outer tunic of the eye, the dissector 
 will proceed to expose the second tunic, which consists of the 
 iris, the ciliary ligament, and the choroid coat. This will 
 require another eye. Holding the eye in one hand, make an 
 incision through the cornea with a sharp scalpel, or puncture 
 it with the scalpel near the centre, and insert the point of one 
 blade of a pair of scissors through the puncture and cut to 
 the margin, taking care to keep the point gently pressed 
 against the inner surface of the cornea, so as not to injure 
 the iris; having reached the edge of the sclerotic coat, the 
 point of the scissors is to be insinuated between it and the 
 ciliary ligament, and then between the sclerotic and choroid 
 coats back to the posterior part of the eye. Success in mak- 
 ing this incision depends mainly on keeping tl^e point of the 
 scissors applied to the inner surface of the cornea and sclero- 
 tic coat as it glides over the iris, the ciliary ligament, and 
 choroid coat. 
 
 Two or three more similar incisions are to be made ; then 
 seizing one of the sections of the cornea with the forceps, 
 reflect it back to its connection with the sclerotica, and then, 
 making slight tension, there will be little or no difficulty in 
 separating the sclerotica from the ciliary ligament and cho- 
 roid coat. The point of a scalpel may be used to facilitate 
 its detachment from the ciliary ligament and divide the ves- 
 sels which pass through the sclerotica to the choroid coat. 
 When the other sections have been turned back in the same 
 manner, a beautiful view of the iris, ciliary ligament, and 
 choroid coat will be obtained. 
 
 As the aqueous humor has escaped, the iris will rest 
 against the lens and ciliary processes, thus obliterating the 
 posterior chamber of the eye. The anterior surface of the 
 iris, with the pupil in its centre, should be observed ; also 
 its attachment to the ciliary ligament. 
 
 The CILIARY LIGAMENT, Fig. 26, e, is about a line in width, of 
 a light color, aridjittached anteriorly to the iris ; posteriorly, 
 to the choroid coat ; and by its external surface to the sclero- 
 tica. It is composed of fibro-cellular tissue ; it is not vascu- 
 lar itself, although it transmits the ciliary arteries to the iris. 
 
104 DISSECTION OF THE HEAD AND NECK. 
 
 The canal of Fontana is a groove situated between the cor- 
 nea, sclerotica, and the ciliary ligament. 
 
 Passing over the choroid coat will be seen the ciliary nerves, 
 Fig. 26; and the two long ciliary arteries, which anastomose 
 around the ciliary ligament with each other and with the 
 anterior ciliary arteries, forming a circle, from which branches 
 are sent into the iris, where another circle is formed. The 
 nerves also penetrate the ligament to reach the iris. 
 
 The veins, Fig. 26, c, in the eye do not accompany the arte- 
 ries ; they are arranged so as to form in the outer layer of 
 the choroid the vasa vorticosa; these form four or five princi- 
 
 Fig. 26. 
 
 CILIARY NERVES. a. Sclerotica. i. Vasa vorticosa. and outer surface of choroid. 
 c. One of the chief trunks of the vasa vorticosa as they leave the choroid. d, d. 
 Ciliary nerves, e. Annulus albidus, or ciliary ligament, f. Iris. -g. Pupil. 
 
 pal trunks which perforate the sclerotica behind the middle 
 of the eyeball. 
 
 The CHOKOID COAT is perforated behind by the optic 
 nerve. Its external surface presents a smooth, shining ap- 
 pearance, being covered by the inner layer of the tunica 
 serosa. Its color is a jet blaqk. 
 
 Having examined the structures now exposed as far as 
 can be done in the present stage of the dissection, the iris 
 may be divided with the scissors into three sections, and re- 
 flected backwards without breaking up its connection with 
 the ciliary ligament. 
 
 The boundaries of the posterior chamber, Fig. 25 (i i), of the 
 
THE EYEBALL. 105 
 
 eye will now be seen, consisting of the iris in front, and the 
 lens and ciliary processes behind. That a space does actually 
 exist behind the iris, and in front of the lens, which is filled 
 with a portion of the aqueous humor, may be proved by 
 freezing an eye, when a thin layer or pellicle of ice will be 
 found separating these two bodies. 
 
 The anterior chamber, Fig. 25 (10), of the eye is the space 
 between the concave surface of the cornea and the anterior 
 surface of the iris ; it is much larger than the posterior. The 
 iris is the only septum between the two chambers, forming 
 the anterior boundary of one, and the posterior boundary of 
 the other. These chambers communicate with each other 
 through the pupil. 
 
 The pupil, Fig. 26, #, is an aperture in the iris which ad- 
 mits the rays of light into the posterior part of the eye. It 
 is not exactly in the centre of the iris, being placed a little 
 nearer to its inner than to its outer margin. In the human 
 eye it is circular, but in the lower animals varies in shape. - 
 
 The IKIS, Fig. 25, 6, and Fig. 26, /, it will be seen, presents 
 two borders and two surfaces. The outer border is attached by 
 areolar tissue to the ciliary ligament, while the inner is free ; 
 the two surfaces are constantly in contact with the aqueous 
 humor. It is the iris which gives to the eye its color, as we 
 say a person has a 'blue eye,' a 'hazel eye,' or a 'black 
 eye.' Its posterior surface is covered with a dark pigment 
 called the uvea, from its resemblance to the color of the grape. 
 Different opinions have been entertained in regard to the 
 structure of the iris. It has been considered by some as 
 composed of an elastic tissue, and by others as consisting of 
 muscular ^fibres arranged in a circular and radiated form ; the 
 former consisting of a narrow band around the pupil, and the 
 latter extending in a radiated manner to its outer circum- 
 ference. It is considerably thicker than the choroid coat, 
 and is abundantly supplied with bloodvessels and nerves. It 
 responds to the stimulus of light applied to the retina, 
 regulating by varying the size of the pupil, the number of 
 rays which shall pass through the lens to that tunic. Some 
 persons have the power of exciting its contractility by voli- 
 tion. The size of the pupil may be increased or diminished 
 by medicinal agents, and by certain conditions of the brain, 
 as in concussion and compression. 
 
106 DISSECTION OF THE HEAD AND NECK. 
 
 During the early part of foetal life, the pupil is occupied by 
 a membrane called the membrana pupillaris this, however, 
 disappears in the human foetus about the seventh month, but 
 in some of the lower animals continues some days after 
 birth. 
 
 The iris should now be detached from the ciliary ligament, 
 and the position of the lens and the ciliary processes sur- 
 rounding it, carefully noticed. The view presented in this 
 stage of the dissection is important, as the student can now 
 obtain a distinct idea of the relative position of the lens to 
 the anterior border of the sclerotic coat, and be able to un- 
 derstand the connection which exists between it and the 
 framework of the eye, as well as the manner in which, by 
 means of this connection, it is kept in its place. 
 
 To separate the choroid coat from the retina, a small open- 
 ing is to be made through it, near the posterior part of the 
 eye. This may be done by detaching it with the point of the 
 scalpel, being careful not to injure the retina beneath it. 
 When the opening is made, the choroid coat may be easily 
 removed by using two pairs of forceps, cutting away with 
 the scissors, from time to time, portions of it which have 
 been detached. In dissecting off this coat, it may be found 
 convenient to place the eye in a shallow vessel containing 
 water. 
 
 The CHOKOID COAT, Fig. 26, 5, is composed of three layers, 
 an external or venous, a middle or arterial (membrana Euy- 
 schiana), and an internal or pigmentary layer. It extends 
 anteriorly to the ciliary ligament and ciliary processes, with 
 which it is intimately connected. Its inner layer consists of 
 six-sided cells, which contain a granular substance. * In some 
 animals, the inner surface of the choroid coat presents poste- 
 riorly a beautiful metallic lustre, known as the tapetum. 
 
 As the choroid coat is removed, a layer of areolar tissue 
 may be seen next to the retina ; this is the membrana Jacobi; 
 by some it is regarded as forming the outer layer of the re- 
 tina. Sometimes it is with difficulty that this membrane can 
 be exposed so as to allow of its demonstration, even as floc- 
 culi floating in water ; at other times it may be distinctly seen. 
 As we approach the anterior border of the choroid coat, in 
 the process of removing it, the termination of the nervous 
 layer of the retina anteriorly will be observed; and also, in 
 front of it, the ciliary processes, proceeding to join the hyaloid 
 
THE EYEBALL. 
 
 107 
 
 Fig. 27. 
 
 processes around the margin of the lens. The view now ob- 
 tained of the ciliary processes from behind, in connection 
 with the one from the posterior chamber, will afford a very 
 accurate idea of their exact position in the eye. They form 
 a sort of septum between the anterior border of the retina 
 and the posterior chamber, while they establish a connection 
 between the lens and the sclerotic coat through the ciliary liga- 
 ment on the one hand, and the hyaloid processes on the other. 
 
 The CILIAKY PEOCESSES, Fig. 27 (4), from sixty to seventy 
 in number, are an interesting portion of the mechanism of the 
 eye. The student will do well to study them faithfully ; they 
 are, as he will see, directly 
 connected with, or related to, 
 nearly all the other parts of 
 this organ. Externally, they 
 are in relation with the ciliary 
 ligament, the choroid coat and 
 iris; internally, with the hy- 
 aloid processes ; anteriorly, 
 with the posterior chamber; 
 and posteriorly, with the re- 
 tina. They are regarded by 
 some as being composed of 
 muscular tissue, and capable of 
 acting on the lens through 
 their connection with the hya- 
 loid processes. In this case, 
 their fixed attachment would 
 be to the ciliary ligament, and 
 through it to the sclerotica. 
 
 The EETINA, Fig. 25 (s), is 
 composed of three layers: the 
 membrana Jacobi, the nervous, and the vascular layer. 
 
 The membrana Jacobi is considered by some a serous 
 membrane. It is more intimately connected with the retina 
 than with the choroid coat. It seems to consist of cylin- 
 drical cells, varying in length, and arranged vertically or 
 obliquely to the surface of the membrane. To expose it the 
 choroid should be removed from behind. 
 
 The nervous layer consists of a soft pulpy substance, re- 
 garded by some as an expansion of the neurine contained 
 
 THE ANTERIOR SEGMENT OP A 
 TRANSVERSE SECTION OP THE GLOBE 
 
 OF THE EYE, SEEN FROM WITHIN. 1. 
 
 The divided ed-ge of the three coats 
 the sclerotic, choroid, and retina. 2. 
 The pupil. 3. The iris ; the surface 
 presented to view in this section being 
 the uvea. 4. The ciliary processes. 5. 
 The anterior border of the retina. 
 
108 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 28. 
 
 in the tubes of the optic nerve. It loses its transparency 
 soon after death. In the human eye its anterior border is 
 serrated. 
 
 The vascular or inner layer 
 is composed principally of a 
 network of vessels proceeding 
 from the central artery of the 
 retina. It is exposed by ma- 
 cerating an eye for two or 
 three days, and then scraping 
 off the nervous layer. It ter- 
 minates anteriorly by passing 
 in between the ciliary and 
 hyaloid processes. This layer 
 is intended for the ramifica- 
 tion of vessels to supply the 
 retina and hyaloid membrane, 
 
 OF THE EYE, SEEN FROM WITHIN. 1. UCrVOUS 
 
 The divided edge of the three coats- The nerVOUS Substance of 
 
 the membrane covering the whole in- -, . . -, . . 
 
 ternal surface is the retina. 2. The the retina IS dellCient in a 
 
 entrance of the optic nerve with the small Spot, about a line from 
 
 SST. 7^e r mc^ the entrance of the optic nerve 
 
 arteria centralis. 4. The foramen of and in the axis of the eye J 
 
 3t5i?*ftrii^ this has been called the fora- 
 teus which surrounds it. 5. A fold of men of Sommenng, Fig. 28 (4). 
 
 the retina, which generally obscures rpfa H m ^ us l uteus j s a yellow 
 the foramen of Sominermg after the . , ,, . , J . 
 
 eye has been opened. spot around this depression or 
 
 foramen. These points in the 
 
 retina are best seen when a transverse vertical section of 
 the eyeball has been made. In this section the retina is 
 commonly thrown into folds by being deprived of the sup- 
 port of the vitreous humor. 
 
 The HYALOID MEMBRANE, or capsule, contains the vitreous 
 humor, Fig. 25 (i s), which occupies about three-fourths of the 
 eyeball posteriorly. It is a thin, delicate, transparent mem- 
 brane, consisting of a general capsule and a large number of 
 septa projecting from its inner surface, so as to form numer- 
 ous small cells or compartments. These cells communicate 
 with each other, as is shown by the gradual escape of the 
 humor when the vitreous body is cut or punctured. The 
 hyaloid body, which includes the hyaloid membrane and the 
 
THE EYEBALL. 109 
 
 vitreous humor, is traversed 'in the centre by a canal, called 
 the canal of Cloquet, Fig. 25 (14), for the transmission of a 
 branch of the central artery of the retina. This artery 
 assists in nourishing the hyaloid membrane, and, probably, 
 the lens. 
 
 Near the margin of the lens the hyaloid membrane 
 divides into two layers, one of which passes in front, and 
 the other behind it. Between these two layers and the 
 margin of the lens is a series of cells, constituting what has 
 been called the canal of Petit, Fig. 25 (9). These cells may 
 be demonstrated by inflating them with a fine blowpipe. 
 
 Just behind the canal of Petit, the hyaloid membrane is 
 somewhat thickened, and presents folds or plicae, named the 
 hyaloid processes. These processes are received into grooves 
 between the ciliary processes. When the latter are removed, 
 the former with the pigment adhering to them form the 
 zonula of Zinn. The vitreous body is in relation with the 
 retina, the ciliary processes, and the lens, which is partly 
 embedded in it. The vitreous humor is composed of water 
 and about two per cent, of saline substances in solution. 
 
 Fig. 29. Fig. 30. 
 
 A SIDE VIEW OF THE ADULT 
 LENS. 1. Its anterior face. 2. Its 
 posterior face. 3, 3. Its circumfer- TRIPLE DIVISION OP THE LENS 
 
 ence. AND THE COURSE OP ITS FIBRES. 
 
 The CRYSTALLINE LENS, Fig, 29, is placed between the 
 vitreous and aqueous humors. Its posterior surface is more 
 convex than the anterior ; but, in this respect, it varies in 
 different eyes, and at different periods of life ; in the foetus 
 it is spheroidal, becoming more flattened as age advances. 
 
 It has a capsule which resembles in structure the elastic 
 10 
 
HARDENED S P,H,T 
 
 110 DISSECTION OF THE HEAD AND NECK. 
 
 layer of the cornea. This is thicker in front than behind. 
 Its inner surface does not adhere to the lens, which escapes 
 readily when the capsule is divided. Behind, it is connected 
 to the hyaloid membrane by delicate areolar tissue. When 
 it is punctured some time after death, a fluid escapes ; this 
 does not probably exist previous to death ; it is called the 
 liquor Morgagni. 
 
 The lens increases in density from the exterior surface 
 towards the centre, which is called the 
 Fig. 31. nucleus. Its transverse diameter is 
 
 about four lines; its antero-posterior 
 about two ; its weight is between three 
 and four grains. When boiled in 
 water, or immersed in dilute acid, it 
 separates into concentric lamellae, 
 and also by slight pressure into three 
 triangular segments, Fig. 31, the bases 
 of which correspond to its circumfer- 
 ence. Its minute structure is not 
 ^11 understood. It consists chemi- 
 
 AND PARTIALLY DiTiDED cally of water, albumen, salts, and an 
 ALONG THE THREE INTERIOR extractive matter. 
 
 PLANES, AS WELL AS INTO ml 7 . , j 
 
 LAMELLA. Magnified 3i di- The aqueous humor is contained in 
 
 ameters. the anterior and posterior chambers 
 
 of the eye. Its weight is about five 
 
 grains. Its composition is the same as that of the vitreous 
 humor. Both surfaces of the iris are bathed by it. 
 
 SECT. VIII. SPHENO-MAXILLAKY KEGION. 
 
 Before commencing the study of this region, that portion 
 of the cranium which is involved in its dissection should be 
 carefully examined. The following are the parts which re- 
 quire special attention : The ramus of the inferior maxilla 
 with its coronoid and condyloid processes, and the posterior 
 dental foramen ; the spheno-maxillary fissure and infra-orbital 
 canal ; the ptery go-maxillary fossa, or the space between the 
 pterygoid process of the sphenoid and tuberosity of the supe- 
 rior maxilla, together with the vidian, palatine, spheno- 
 palatine, and round foramina, which open into it ; also the 
 foramina ovale and spinosum, which are situated behind the 
 base of the pterygoid process. 
 
SPHENO-MAXILLARY REGION. Ill 
 
 The portions of the'skull concerned in this dissection may be 
 arranged in three planes : First, the zygoma with the super- 
 ficial portion of the malar bone. Second, the external portion 
 of the superior maxilla, the glenoid cavity, and eminentia 
 articularis of the temporal bone, and that part of the greater 
 wing of the sphenoid situated in the zygomatic fossa. Third, 
 the tuberosity of the superior maxilla, with the pterygoid 
 process, and the horizontal portion of the great wing of the 
 sphenoid. 
 
 The MASSETER muscle, Fig. 61 (ie), which was noticed in 
 the superficial dissection of the face, should now be more 
 accurately observed. It is a powerful muscle, consisting of 
 two parts, an external and an internal. The external is the 
 largest ; it arises, chiefly tendinous, from the anterior portion 
 of the zygomatic arch, and the malar process of the superior 
 maxilla, passes downwards and backwards, and is inserted 
 into the lower half of the ramus of the inferior maxilla, 
 extending as far back as the angle. The internal portion 
 arises from the posterior part of the arch ; its fibres pass 
 downwards, most of them in a vertical direction, and are 
 inserted into the upper half of the ramus of the lower jaw. 
 The lower portion of the internal is overlapped by the fibres 
 of the external. When both masseter muscles act, they 
 approximate the lower jaw to the upper; when the exter- 
 nal portions alone act, they move it forwards ; and when 
 the internal portions act, they draw it backwards. By 
 acting separately, they can move the jaw laterally. The 
 masseter may now be removed. In doing this, the masseteric 
 artery and nerve should be sought ; the former is a branch of 
 the internal maxillary, and the latter, of the second division 
 of the fifth pair. They penetrate the internal surface of the 
 muscle, just above the sigmoid notch, where they may be 
 easily found. 
 
 The masseter having been removed, the zygomatic arch 
 and the contiguous portion of the malar bone may now be 
 cut away, thus exposing the insertion and lower part of the 
 temporal muscle, which was described with the soft parts on 
 the outside of the cranium. 
 
 The coronoid process should now be cut through, and 
 turned upwards with the temporal muscle, care being taken 
 not to injure the parts beneath. In doing this, the deep 
 
112 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 temporal arteries, Fig. 33 (17, i s), and nerves, Fig. 37 (22), will 
 be seen penetrating the internal surface of the muscle. Each 
 consists of an anterior and posterior branch, the artery being 
 derived from the internal maxillary, and the nerve from the 
 third division of the fifth pair. A branch of the superior 
 maxillary nerve may also be seen passing through the outer 
 wall of the orbit, and penetrating the muscle in the anterior 
 part of the fossa. 
 
 The inferior maxilla should now be divided transversely 
 through the base of the condyloid process, and vertically 
 through the body in a line corresponding to the last molar 
 tooth. In doing this, both the saw and chisel may be advan- 
 tageously employed. Before cutting through the condyloid 
 process, the masseteric artery and nerve should be traced to- 
 ward their origin and pushed away. 
 
 If the section of bone between the two incisions be care- 
 fully turned outwards and backwards, without detaching it 
 from the structures beneath, the following parts will be ex- 
 posed : 
 
 The PTERYGOIDEUS EXTERNUS, Fig. 32 (i), situated in the 
 upper part of this region, arises by two heads, the upper and 
 smaller, from the great wing of the sphenoid, near the root of 
 
 the pterygoid process, the lower 
 one from the outer plate of the 
 pterygoid process. These two 
 heads pass horizontally out- 
 wards, and unite to be inserted 
 by a short tendon into the neck 
 of the condyle of the lower jaw, 
 the internal lateral ligament and 
 the interarticular cartilage. 
 
 The internal maxillary artery, 
 Fig. 33 (i 2), crosses over the ex- 
 ternal surface of this muscle from 
 its lower border near the con- 
 A P A G E CH dyloid process, to the pterygo 
 GREATER PART OF THE lUiius OP maxillary fossa. The masse- 
 
 Fig. 32. 
 
 . 
 
 MUSCLES INTO VIEW. i. The sphe- upper margin from within out- 
 
 noid origin of the external pterygoid war d s an d in its COUrSC Sends 
 
 muscle. 2. Its pterygoid origin. 3. -!, -, -, ,-, 
 
 The internal pterygoid muscle. & Small branch to the temporo- 
 
SPHENO-MAXILLARY REGION. 113 
 
 maxillary articulation. The buccal nerve usually arises by 
 two roots, which unite after perforating the pterygoideus 
 externus; it then runs downwards and forwards over this 
 muscle to the buccinator; at the anterior border of the 
 masseter it becomes superficial, and is distributed to the 
 buccal portion of the face. The posterior deep temporal 
 artery in the first part of its course runs on this muscle ; also 
 the buccal artery. 
 
 The PTERYGOIDEUS INTERNUS, Fig. 32 (3), is situated deeper 
 and lower down than the externus. It arises from the pterygoid 
 fossa, and passes downwards and somewhat backwards, and is 
 inserted into the internal surface of the angle and ramus of 
 the lower jaw. In form it resembles the masseter. The 
 pterygoid muscles, when they act on both sides, draw the jaw 
 forwards and upwards ; and when they act on one side only, 
 they move the jaw laterally, as in grinding the food. 
 
 The lingual branch, Fig. 37 (23), of the inferior maxillary 
 nerve will be seen crossing this muscle in a direction from 
 above downwards. The chorda tympani joins the lingual at 
 the posterior border of the muscle, having come from the 
 glenoid fissure to this point, along the deep surface of the 
 external pterygoid. 
 
 The mylo-hyoid branch, Fig. 37 (23), of the inferior dental 
 nerve, with a small artery accompanying it, is situated close 
 to the inner surface of the inferior maxilla, being frequently 
 lodged in a groove in the bone just above the insertion of 
 the pterygoideus internus. 
 
 The pterygoideus externus may now be dissected away so 
 as to expose the following branches of the internal maxillary 
 artery, and inferior maxillary nerve, and the posterior dental 
 branch of the superior maxillary nerve. The main trunk 
 of the artery should first be traced to the pterygo-maxillary 
 fossa. The chorda tympani will be seen crossing the artery 
 almost at right angles to join the lingual nerve. The infe- 
 rior dental artery, Fig. 33 (i 4), and nerve, Fig. 37 (24), may be 
 easily found as they enter the posterior dental foramen, and 
 traced from this point to their origin. 
 
 The mylo-hyoid nerve comes from the dental just before it 
 enters the foramen. The middle meningeal artery passes up- 
 wards and forwards to the foramen spinosum, through which 
 it enters the cavity of the cranium. It passes between two 
 
 10* 
 
114 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 roots of the temporo-auricular nerve, which passes backwards 
 and upwards between the cervix of the condyle and the 
 auditory meatus, giving off branches to anastomose with the 
 facial, to ascend over the zygoma to the temporal region, 
 to the meatus and tympanum, and also to the articulation 
 and the parotid gland. 
 
 Fig. 33. 
 
 A VIEW OF THE INTERNAL MAXILLARY ARTERY, AS GIVEN BY SECTIONS OP 
 THE BONES OP THE HEAD AND FACE. 1. Primitive carotid artery. 2. External 
 carotid. 3. Internal carotid. 4. Section of the superior thyroid artery. 5. Point 
 where the facial artery crosses the lower jaw. 6. Inferior coronary artery. 7. Su- 
 perior coronary artery. 8. Point of anastomosis of facial with the nasal branch of 
 ophthalmic. 9. The occipital artery. 30. Posterior auricular. 11. Temporal ar- 
 tery. 12. Origin of the internal maxillary artery. 13. Meningea magna of the 
 dura mater ramifying over its surface. 14. Inferior dental artery in the alveolar 
 processes of the lower jaw. 15. The pterygoid arteries. 16. The masseteric arteries. 
 17. Deep-seated posterior temporal artery. 18. Deep-seated anterior temporal ar- 
 tery. 19. Buccal arteries. 20. Infra-orbital. 21. Posterior palatine. 22. Origin 
 of the pterygoid artery. 23. Origin of the spheno-palatine. 
 
 The tympanic artery goes through the Glaserian fissure to 
 the tympanum. The pterygoid branches, irregular in their 
 origin, penetrate the internal surface of the pterygoid mus- 
 cles. The anterior meningeal artery arises a little in advance 
 of the middle meningeal, and passes through the foramen 
 ovale to the dura mater. The deep temporal, masseteric, and 
 
SPHENO-MAXILLAEY REGION. 
 
 115 
 
 buccal branches have already been seen. The superior dental 
 and infra- orbital come off just before the main trunk enters 
 the pterygo-inaxillary fossa. The superior dental branch 
 penetrates the tuberosity of the superior maxilla to be dis- 
 tributed to the molar and bicuspid teeth. The infra-orbital 
 passes through the posterior part of the spheno-maxillary 
 fissure to enter a canal in the floor of the orbit. The re- 
 maining branches of the internal maxillary artery cannot 
 be seen at this stage of the dissection. The internal maxil- 
 lary vein corresponds with the artery and its branches. It 
 communicates with the cavernous sinus and the facial vein. 
 The posterior superior dental nerve arises from the superior 
 maxillary in the posterior part of the spheno-maxillary fis- 
 sure, and runs some distance on the tuberosity of the supe- 
 rior maxilla, which it penetrates to reach the molar teeth. 
 
 The TEMPORO-MAXILLARY ARTICULATION should now be 
 examined, so that the structures connected with it may 
 be removed. They consist of an external and an internal 
 lateral ligament, a capsular ligament, an interarticular fibro- 
 cartilage, and two synovial sacs. 
 
 The EXTERNAL LATERAL LIGAMENT, Fig. 34 (s), arises from 
 the tubercle of the zygomatic 
 process of the temporal bone, 
 and is inserted into the outer 
 part of the cervix of the con- 
 dyle of the lower jaw. 
 
 The INTERNAL LATERAL 
 LIGAMENT, Fig. 35 (4), arises 
 from the spinous process of 
 the sphenoid bone, passes 
 downwards and forwards to 
 be inserted into the. inner 
 border of the posterior dental 
 foramen. It is longer than 
 the external, and is separated 
 from the bone by the internal 
 maxillary artery, and the in- 
 ferior dental nerve and ar- 
 tery, thus preventing the in- 
 ternal pterygoid muscle from 
 
 Fig. 34. 
 
 AN EXTERNAL VIEW OP THE ARTICU- 
 LATION OF THE LOWER JAW. 1. The zy- 
 gomatic arch. 2. The tubercle of the 
 zygoma. 3. The ramus of the lower jaw. 
 4. The mastoid portion of the temporal 
 bone. 5. The external lateral ligament. 
 6. The stylo-maxillary ligament. 
 
 pressing upon them when 
 
116 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 contracting. Some, of its fibres which adhere to the cap- 
 sule have been designated the short internal lateral liga- 
 ment. 
 
 Fig. 35. 
 
 AN INTERNAL VIEW OP THE ARTICULA- 
 TION OP THE LOWER JAW. 1. A section 
 through the petrous portion of the temporal 
 bone and spinous process of the sphenoid. 
 2. An internal view of the ramus, and part 
 of the body of the lower jaw. 3. The in- 
 ternal portion of the capsular ligament. 
 4. The internal lateral ligament. 5. A 
 small interval at its insertion, through 
 which the mylo-hyoid nerve passes. 6. 
 The stylo-maxillary ligament, a process of 
 the deep cervical fascia. 
 
 The CAPSULAK LIGAMENT arises principally from the 
 articular eminence and glenoid fissure, and is inserted into 
 
 the neck of the condyle. It 
 adheres closely to the interarti- 
 cular fibro-cartilage, and keeps 
 it in place. In front there is a 
 deficiency in it for the insertion 
 of the external pterygoid mus- 
 cle. 
 
 The INTERARTICULAR Fi- 
 
 BRO-CAKTILAGE, Fig. 36 (3, e), 
 is placed between the glenoid 
 cavity and the condyle of the 
 IN THIS SKETCH A SECTION HAS BEEN jaw, dividing this space into 
 
 two cavities. It is elongated 
 transversely. Its margins are 
 blended with the ligaments sur- 
 rounding the joint, and in front 
 with the tendon of the external 
 pterygoid muscle. 
 
 CARRIED THROUGH THE JOINT, IN OR- 
 DER TO SHOW THE NATURAL POSITION 
 OP THE INTERARTICULAR FIBRO-CARTI- 
 LAGE, AND THE MANNER IN WHICH IT 
 IS ADAPTED TO THE DIFFERENCE OF 
 FORM OF THE ARTICULATING SURFACES. 
 
 1. The glenoid fossa. 2. The eminen- 
 tia articularis. 3. The interarticular 
 fibro-cartilage. 4. The superior syno- 
 vial cavity. 5. The inferior synovial 
 cavity. 6. An interarticular fibro- 
 cartilage, removed from the joint, in 
 order to show its oval and concave 
 form ; it is seen from below. 
 
 There are two SYNOVIAL 
 MEMBRANES, Fig. 36 ( 4 , 5), 
 which line respectively the pa- 
 rietes of the two cavities of this 
 joint, the superior being the larger. The interarticular fibro- 
 cartilage is sometimes deficient in the centre, in which case 
 
SPHENO-MAXILLARY REGION. 117 
 
 the two sacs may communicate with each other. This artic- 
 ulation should be studied with reference to luxation, and 
 the action of the masticatory muscles. 
 
 The STYLO-MAXILLARY LIGAMENT, Fig. 34 (e), arises 
 from the styloid process, and is inserted into the angle of 
 the lower jaw, furnishing an attachment for a reflection of 
 the deep cervical fascia, and for a part of the stylo-glossus 
 muscle. 
 
 The PTERYGO -MAXILLARY LIGAMENT is attached above to 
 the external wing of the pterygoid process, and below to the 
 base of the coronoid process of the lower jaw. The buccinator 
 arises in part from its anterior, and the superior constrictor 
 of the pharynx from its posterior border. 
 
 The remaining portion of the malar bone, with the malar 
 process of the maxilla, and that part of the great wing of the 
 sphenoid which forms the posterior boundary of the spheno- 
 maxillary fissure, should now be removed, so as to expose 
 the upper part of the pterygo-maxillary fossa. The infra- 
 orbital nerve and artery may now be traced into and through 
 the infra-orbital canal. The roof of this canal may be best 
 cut away with a small sharp chisel. If the nerve be slightly 
 raised in the canal, the anterior dental branch will be seen 
 leaving it to enter the antrum Highmori. Two or three fila- 
 ments also leave it to go to the mucous membrane lining the 
 antrum. The infra-orbital nerve, Fig. 87 (7), may now be 
 traced back to the foramen rotundum, in doing which the 
 origin of the posterior dental and orbital branches should be 
 sought. The former consists of two branches, a superior and 
 an inferior; the latter enters the orbit and divides into the 
 malar and temporal branches. The infra-orbital artery has 
 the same course and distribution as the nerve. The infra- 
 orbital vein communicates with the facial by means of the 
 alveolar. 
 
 The upper and outer wall of the antrum may now be cut 
 away to follow the dental arteries and nerves in their dis- 
 tribution. To trace these nerves in their minute ramifications, 
 a fresh bone, softened in diluted nitric or muriatic acid, should 
 be used. 
 
 The posterior superior dental nerve, Fig. 37 (7), enters the 
 upper part of the antrum, and anastomoses with the posterior 
 inferior, and anterior dental nerves. 
 
118 DISSECTION OF THE HEAD AND NECK. 
 
 The posterior inferior enters the bone lower down, and 
 divides into filaments which go to the molar and bicuspid 
 teeth. 
 
 The anterior dental nerve, Fig. 37 (i s), which enters from the 
 infra-orbital canal, passes at first horizontally and then down- 
 wards in the anterior wall of the antrum ; it sends filaments 
 to the cuspid and incisor teeth, and also to the bone, and 
 the lower meatus of the nose. 
 
 Fig. 37. 
 
 * A VIEW OP THE DISTRIBUTION OF THE TRIFACIAL OR 5TH PAIR. 1. Orbit. 2. 
 
 Antrum of Highmore. 3. Tongue. 4. Lower maxilla. 5. Root of 5th pair, forming 
 the ganglion of Gasserius. 6. 1st branch, ophthalmic. 7. 2d branch, superior maxil- 
 lary. 8. 3d branch, inferior maxillary. 9. Frontal branch, dividing into supraorbital 
 and frontal at 14. 10. Lachrymal branch, dividing before entering the lachry- 
 mal gland. 11. Nasal branch. Just under the figure is the long root of the lenticular 
 or ciliary ganglion, and a few of the ciliary nerves. 12. Internal nasal, disappearing 
 through the anterior ethmoidal foramen. 13. External nasal. 14. Supra orbital 
 and frontal. 15. Infra-orbital nerve. 16. Posterior dental branches. 17. Mid- 
 dle dental branch. 18. Anterior dental nerve. 19. Terminating branches of 
 infra-orbital, called labial and palpebral. 20. Subcutaneus malae, or orbital branch. 
 21. Pterygoid or recurrent, from Meckel's ganglion. 22. Five anterior branches of 
 3d branch of 5th, being nerves of motion, and called masseteric, temporal, pterygoid 
 and buccal. 23. Lingual branch joined at an acute angle by the chorda tympani. 
 24. Inferior dental nerve terminating in, 25. Mental branches. 26. Superficial tem- 
 poral nerve. 27. Auricular branches. 28. Mylo-hyoid branch. 
 
SPHENO-MAXILLARY REGION. 119 
 
 The GANGLION OF MECKEL, or SPHENO-PALATINE GANG- 
 LION, may now be examined, with its communicating branches. 
 For this purpose the upper part of the posterior wall of the 
 antrum may be removed, with enough of the great wing of 
 the sphenoid fairly to expose the foramen rotundum. If we 
 now divide the infra-orbital nerve, and turn it backwards, we 
 shall observe two small filaments going downwards to join a 
 small reddish mass, of a somewhat triangular shape, which is 
 the ganglion of Meckel. The following nerves may be dis- 
 covered proceeding from it in different directions : 
 
 The SPHENO-PALATINE leaves it on the inner side, and 
 passes almost immediately through the spheno-palatine fora- 
 men to enter the nose just behind the superior meat us, where 
 it divides into branches which will be described with the 
 nasal cavity. 
 
 The PALATINE NERVE, consisting sometimes of two or 
 three divisions, leaves it on the lower side, and enters the 
 palatine canal to divide into an anterior, middle and posterior 
 branch. The anterior is distributed to the roof of the mouth ; 
 the middle and posterior to the soft palate, the amygdala 
 and uvula. The posterior palatine branch not unfrequently 
 passes through a separate canal in the palatine bone. 
 
 The YIDIAN NERVE passes backwards from the ganglion 
 to the vidian or pterygoid canal, and through it into the 
 cavity of the cranium. It sends several small filaments to 
 the sphenoidal sinus- These nerves cannot at present be con- 
 veniently followed beyond the pterygo-maxillary fossa. The 
 dissection of this ganglion and its nerves, may be made from 
 the nasal cavity, by breaking away the vertical plate of the 
 palatine bone which forms a septum between the nose and 
 the pterygo-maxillary fossa. If the student wishes, he can 
 dissect one side of the head as above described, and the other 
 side from the nasal cavity. 
 
 As much of the great wing of the sphenoid, with the emi- 
 nentia articularis of the temporal bone must now be cut 
 away as shall be necessary to expose the foramen ovale. 
 Divide the dental and gustatory nerves and turn them up 
 towards the foramen ; the otic ganglion will now be observed 
 just below the foramen and on the inner side of the inferior 
 maxillary nerve. 
 
 The OTIC GANGLION is a small, reddish body, like the gan- 
 
120 DISSECTION OF THE HEAD AND NECK. 
 
 glion of Meckel. It gives off the following nerves: a fascicu- 
 lus, which communicates with the inferior maxillary ; ptery- 
 goid and auricular branches, the latter being a motor and 
 the former a sensor filament; and several filaments, which 
 connect it with the sympathetic, being sent to the plexus on 
 the middle meningeal artery. Two muscular branches also 
 leave this ganglion, one supplying the tensor tympani, and 
 the other the tensor palati. Posteriorly it gives off the super- 
 ficial petrosal nerve, which perforates the petrous bone to 
 join the vidian and a branch from the glosso-pharyngeal in 
 the tympanum. This ganglion, like that of Meckel, may be 
 reached from within by cutting away the levator palati 
 muscle, and finding the cartilaginous portion of the Eusta- 
 chian tube, near the osseous extremity of which it is situated. 
 
 SECT. IX. DISSECTION OF THE EAR. 
 
 The organ of hearing is divided into the external, middle, 
 and internal portions. The first is covered by the skin, the 
 second is lined by mucous membrane, and the third has no 
 external communication. 
 
 The EXTERNAL EAR, Fig. 38, is divided into the auricle 
 and meatus. The framework of the auricle consists of a 
 nbro-cartilage, which gives to it the peculiar form it presents, 
 and allows of a great degree of flexibility. It is very firmly 
 attached to the margin of the meatus, so much so that the 
 weight of the body may be sustained by the auricles. The 
 following points are to be noticed upon each auricle: 
 
 The cranial surface is, generally convex, while the facial 
 surface is concave. The deepest part, that which leads into 
 the meatus, is called the concha. The projection in front 
 of this, and partly covering it, is the tragus. When the 
 tragus is pressed inwards, it covers the meatus. Hairs grow 
 from its posterior surface. A little lower down, behind and 
 opposite to the tragus, is the anti-tragus. This is smaller than 
 the tragus, and separated from it by a deep notch called the 
 notch of the concha, or incisura tragica. The anti-helix is the 
 ridge which commences just above the anti-tragus, curves 
 upwards and forwards to bifurcate, leaving a depression be- 
 tween its divisions called the scaphoid fossa. The external 
 curved border of the ear is the helix. The helix is separated 
 
OF THE EAB. 
 
 121 
 
 from the anti-helix by the fossa innominata. The lower 
 pendulous part of the auricle is the lobe. It consists of a 
 duplicature of the skin, with a small portion of adipose sub- 
 stance. 
 
 The helix and anti-helix unite behind to form the processus 
 caudatus, which is separated 
 from the anti-tragus by a fis- Fi S- 38 - 
 
 sure. The fissure of the tragus 
 is situated on its anterior sur- 
 face. The fissure of the helix is 
 just above the tubercle to which 
 is attached the attrahens aurem 
 muscle. 
 
 The LIGAMENTS of the auricle 
 are intrinsic and extrinsic. The 
 former consist of ligamentous 
 bands, intended to preserve the 
 fibro-cartilage in its proper 
 form, and to occupy the fis- 
 sures. The latter consist of, a 
 posterior, which connects the 
 concha to the mastoid process; 
 an anterior, which extends from 
 the process of the helix to the 
 zygomatic arch; and of a liga- 
 ment, which connects the tragus 
 to the same part. 
 
 The INTRINSIC MUSCLES, Fig. 
 39, of the auricle are the follow- 
 ing. The helicis major is situated 
 
 just above the tragus, on the anterior part of the helix. It 
 consists of a narrow band of muscular fibres, tendinous at 
 each extremity. 
 
 The helicis minor occupies the helix where it projects into 
 the concha. 
 
 The anti-tragicus extends from the external surface of the 
 anti-tragus to the processus caudatus. 
 
 The tragicus lies vertically upon the external surface of the 
 tragus. 
 
 The transversus auriculae, is situated on the cranial surfape 
 of the auricle, extending from the concha to the helix. 
 11 
 
 A VIEW OP THE LEFT EAR IN ITS 
 NATURAL STATE. 1,2. The origin and 
 termination of the helix. 3, 3. The 
 anti-helix. 4. The anti-tragus. 5. 
 The tragus. 6. The lobe of the ex- 
 ternal ear. 7. Points to the scapha, 
 and is on the front and top of the 
 pinna. 8. The concha. 9. The mea- 
 tus auditorius externus. 
 
122 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 39. 
 
 The AETEKIES of the auricle are derived from the poste- 
 rior auricular, and the auricular branches of the temporal. 
 Quite a large branch from the posterior auricular enters the 
 concha between the anti-helix and the processus caudatus. 
 
 The NERVES come from several sources ; as the auricula- 
 ris magnus, the facial, the fifth, and the pneumogastric. The 
 concha is supplied by a branch which perforates the cartilage 
 just above the anti-tragus. 
 
 The meatus auditor ius externus, Fig. 41 (s), is about an inch 
 in length. The inner half of it is osseous, and belongs to the 
 temporal bone. It is slightly curved, with its convexity 
 upwards. Its lower wall is longer than the upper, on account 
 of the oblique position of the membrana tympani. A trans- 
 verse vertical section of it presents 
 a figure somewhat oval or ellipti- 
 cal, the vertical diameter being the 
 longest. The middle of it is not 
 quite so large as the extremities. 
 The outer portion is partly fibrous 
 and partly cartilaginous. The 
 fibrous structure forms about the 
 upper fourth of the canal. There 
 are two or three fissures in the 
 cartilaginous portion called the 
 fissures of Sanlorini. The struc- 
 ture of this part of the canal 
 admits of some mobility. 
 
 The meatus is lined by a reflec- 
 tion of the skin from the auricle. 
 It is very thin and delicate, and 
 covered with fine hairs. In old 
 persons there are usually some 
 quite long stiff hairs near the ex- 
 ternal orifice, which seem to afford 
 some protection against the en- 
 trance of foreign bodies. In the 
 structure of the lining membrane 
 are a number of sebaceous follicles called the ceruminous 
 glands. They are of a yellowish color when cut, and secrete 
 an unctuous substance resembling wax. This sometimes ac- 
 cumulates and becomes hard, causing deafness. The meatus 
 should be observed with care by the student. It may be 
 
 REPRESENTS THE CARTILAGE OP 
 THE EXTERNAL EAR WITH SOME OP 
 ITS MUSCLES. 1, 2. The helicis 
 major muscle on the front of the 
 helix. 3, 4. The helicis minor mus- 
 cle. 5, 6. The tragicus muscle on 
 the front surface of the tragus. 7, 
 8. The anti-tragicus muscle. 
 
MIDDLE EAR, OR TYMPANUM. 123 
 
 examined by allowing the rays of light to enter in a direction 
 to fall on the membrana tympani, and to expose the whole of 
 the interior surface of the meatus. 
 
 THE MIDDLE EAR, OR TYMPANUM. 
 
 The tympanum is a small circular cavity, situated between 
 the meatus and the labyrinth, or internal ear. It resembles 
 somewhat a section of the meatus, or it may be regarded as 
 a prolongation of that tube into the base of the petrous por- 
 tion of the temporal bone, to the extent of about one-fourth 
 of an inch. It is cut off from the meatus by a membrane, 
 which forms its external wall, while the septum between it 
 and the internal ear forms its internal wall. This cavity is 
 about half an inch in diameter, which is rather greater than 
 that of the meatus. 
 
 In studying it, three surfaces are presented ; its external 
 and internal walls, and its circumference. 
 
 Fig. 40. 
 
 MEMBRANA TYMPANI FROM THE OUTER (A) AND FROM THE INNER (B) SIDES. 1. 
 mernbrana tympani. 2. Malleus. 3. Stapes. 4. Incus. 
 
 Its external wall is formed by the membrana tympani, and 
 the inner margin of the parietes of the meatus. The mem- 
 brana tympani, Fig. 40, A, B, is inclined inwards in a direction 
 from above downwards, thus increasing the length of the floor 
 of the meatus. It is concave externally, with its correspond- 
 ing convexity projecting into the tympanum. It has attached 
 to the upper part of its inner surface the handle of the malleus. 
 It is composed of three laminae. The outer one is reflected 
 from the parietes of the meatus, and the inner one from the 
 walls of the tympanum ; the middle one is fibrous, and is fixed 
 to a groove in the circumference of the tympanic orifice of the 
 
124 DISSECTION OF THE HEAD AND NECK. 
 
 meatus. In the foetus it is attached to an osseous ring, which 
 is distinct from the rest of the petrous bone. It contains 
 some small vessels. The following points are to be noticed 
 on the inner wall: 
 
 The fenestra ovalis, Fig. 41 (10), is situated in the upper 
 part, directly opposite the roof of the meatus. Its long 
 diameter is inclined downwards and forwards. The upper 
 border of it is arched, while the lower is nearly straight. It 
 is occupied in the recent subject by the stapes and by a mem- 
 brane. The fenestra rotunda is located in the posterior part 
 of the inner wall, and lower down than the fenestra ovalis. 
 It is situated at the bottom of quite a deep fossa. Between 
 and below these two orifices is seen the promontory. Several 
 small grooves are sometimes observed on the promontory for 
 the lodgment of filaments of Jacobson's nerve; instead of 
 grooves, they may exist in the form of canals in the bone. 
 Just in front of, and a little below the anterior extremity of 
 the fenestra ovalis, is the tympanic orifice of the canal for the 
 tensor tympani muscle. The processus cochleariformis is a 
 projection of the wall of this canal into the tympanum. The 
 aqueduct of Fallopius forms a curved ridge just above the 
 fenestra ovalis. Behind the fenestra ovalis, and near the 
 posterior wall, is the pyramid, with a small opening upon its 
 apex which is occupied by the stapedius muscle. The canal 
 for the transmission of Jacobson's branch of the glosso- 
 pharyngeal nerve enters the tympanum at the lower part of 
 the promontory. 
 
 In the posterior part of the tympanum is a large opening 
 which leads into the mastoid cells. These cells are lined by 
 mucous membrane, and contain air during life. They are 
 analogous to the frontal and sphenoidal sinuses. Below the 
 mastoid opening is a small foramen, through which passes 
 the chorda tympani nerve, after it leaves the portio dura. 
 
 There is nothing in the floor of the tympanum which 
 deserves particular notice. It is quite thin, and is formed 
 by a prolongation inwards of the floor of the meatus. It 
 corresponds to the parotid fossa externally. 
 
 In the anterior part of the tympanum is the fissure of 
 Glaserius, and the small foramen through which the chorda 
 tympani makes its exit. There is also a small opening for 
 the superficial petrosal branch of Jacobson from the otic 
 ganglion. The tympanic orifice of the Eustachian tube, 
 Fig. 41 (is), occupies the greater part of the anterior wall of 
 
MIDDLE EAK, OK TYMPANUM. 
 
 125 
 
 the tympanum. The osseous portion of this tube is separated 
 from the canal for the tensor tympani muscle by the septum 
 
 Fig. 41. 
 
 A DIAGRAM OP THE EAR. p. The pinna, t. The tympanum. I. The laby- 
 rinth. 1. The upper part of the helix. 2. The anti-helix. 3. The tragus. 4. 
 The anti-tragus. 5. The lobulus. 6. The concha. 7. The upper part of the fossa 
 innominata. 8. The meatus. 9. The membrana tympani, divided by the section. 
 10. The three little bones, crossing the area of the tympanum, malleus, incus, and 
 stapes ; the foot of the stapes blocks up the fenestra ovalis upon the inner wall of 
 the tympanum. 11. The promontory. 12. The fenestra rotunda ; the dark open- 
 ing above the ossicula leads into the mastoid cells. 13. The Eustachian tube; the 
 little canal upon this tube contains the tensor tympani muscle in its passage to the 
 tympanum. 14. The vestibule. 15. The three semicircular canals horizontal, 
 perpendicular, and oblique. 16. The ampullae upon the perpendicular and hori- 
 zontal canals. 17. The cochlea. 18. A depression between the convexities of the 
 two tubuli which communicate with the tympanum and vestibule : the one is the 
 scala tympani, terminating at 12, the other is the scala vestibuli. 
 
 cochleariforme. This part of the tube is small in the pre- 
 pared bone, and much smaller in the recent bone before its 
 membranous lining is removed. 
 
 In the upper wall is a depression which is occupied by 
 the head of the malleus and the short leg of the incus. This 
 wall is perforated by several foramina, for the transmission 
 of vessels to the dura mater. 
 
 The ossicula auditus, or small bones of the ear, Fig. 42, 
 are the malleus, incus, orbiculare, and stapes. 
 
126 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 42. 
 
 These form a chain, extending across the tympanum from 
 the membrana tympani to the fenestra ovalis. 
 
 The MALLEUS is situated next to the membrana tympani. 
 It consists of a head, neck, handle, and two processes, long 
 and short. The head is round and smooth above, and con- 
 cave below, for articulating with the incus. From the neck, 
 which is flattened, the two processes arise ; the short one is 
 directed to the upper part of the membrana tympani, against 
 which it rests; the long one, called the processus gracilis, 
 arises from the anterior part of the neck, and projects for- 
 wards towards the Glaserian fissure. The laxator tympani 
 muscle is inserted into it. The handle, or manubrium, has 
 nearly a vertical position, and adheres closely to the fibrous 
 layer of the membrana tympani, the radiating fibres of which 
 
 diverge from it. It extends to 
 the centre of the membrane, and 
 curves slightly outwards. 
 
 The INCUS is placed on the inner 
 side of the preceding. It presents 
 a body and two processes. There 
 is a concavity on the body for the 
 reception of the head of the mal- 
 leus. The short process is of a 
 conical shape, and directed back- 
 wards to the opening into the 
 mastoid cells. Its extremity is 
 LEFT EAR attached by a ligament. The long 
 process descends a little behind, 
 and nearly parallel to the handle 
 of the malleus, and a short dis- 
 tance from it. Its lower end is 
 curved inwards. 
 
 The ORBICULAKE is very fre- 
 
 OSSICLES OP THE 
 
 ARTICULATED, AND SEEN PROM 
 
 is the constriction, or neck. g. 
 Processus gracilis, or long process, 
 at the root of which is the short 
 process. Ti. Manubrium, or han- 
 dle, sc. Short crus; and Ic, long 
 crus of the incus. The body of -. 
 
 this bone is seen articulating with quently nxed to the extremity of 
 
 the long process of the incus. It 
 is round, and flattened like a disk. 
 The STAPES presents a head, two 
 crura, and a base. Its position is 
 horizontal. The head articulates 
 
 with the orbiculare, and the base fits into the fenestra ovalis. 
 
 The posterior crus is longer and more curved than the anterior. 
 
 the malleus and its long crus, 
 through the medium of the orbi- 
 culare , here partly concealed, 
 with the stapes, s. Base of the 
 stapes. Magnified three diame- 
 ters. 
 
INTERNAL EAR, OR LABYRINTH. 127 
 
 These bones are connected to each other by capsular liga- 
 ments, which contain sy no vial membranes. They are also 
 connected to the parietes of the tympanum by three liga- 
 ments. The head of the malleus is attached to the roof by 
 a ligament ; the short process of the incus is connected to 
 the opening into the mastoid cells, and the base of the stapes 
 to the margin of the fenestra ovalis, by ligamentous fibres. 
 
 The muscles of the tympanum are the tensor tympani, the 
 laxator tympani, and the stapedius. 
 
 The TENSOR TYMPANI, Fig. 45, a, arises from the cartilage 
 of the Eustachian tube and the contiguous portion of the 
 sphenoid bone, and also from the bony canal which it occu- 
 pies just above the septum cochleariforrne. It enters the 
 anterior part of the tympanum, and is reflected outwards, to 
 be inserted into the handle of the malleus immediately below 
 the processus gracilis. 
 
 The LAXATOR TYMPANI is regarded very generally as liga- 
 mentous, and not muscular in its structure. It is attached to 
 the point of the processus gracilis, and passes through the 
 Glaserian fissure to become connected with the internal lateral 
 ligament of the temporo-maxillary articulation. 
 
 Another laxator has been described extending from the 
 upper part of the membrana tympani to the malleus. 
 
 The STAPEDIUS arises from a depression on the pyramid, 
 and passes downwards and forwards to be inserted into the 
 neck of the stapes.- 
 
 The tympanum is lined by a very thin delicate mucous 
 membrane. This adheres closely to the periosteum beneath 
 it. It invests the small bones, and covers the vessels and 
 nerves ; is reflected into the mastoid cells, but not into the 
 labyrinth ; closes the fenestra rotunda, and the space between 
 the crura of the stapes. 
 
 THE INTERNAL EAR, OR LABYRINTH. 
 
 The internal ear contains the peripheral expansion of the 
 nerve of hearing. It lies deep in the petrous portion of the 
 temporal bone, and consists of several compartments. From 
 its complex character it has been called the labyrinth. Its 
 compartments are the vestibule, the semicircular canals, three 
 in number, and the cochlea. The vestibule is situated in 
 
128 DISSECTION OF THE HEAD AND NECK. 
 
 the centre, with the cochlea in front and the semicircular 
 canals behind. These osseous cavities contain within them 
 membranous sacs, which constitute the membranous laby- 
 rinth. A fluid fills the sacs, and also the osseous cavities 
 outside of the sacs. 
 
 The VESTIBULE, Fig. 41 (i 4), is placed between the fenestra 
 ovalis on the external side, and the macula cribrosa at the 
 bottom of the meatus auditorius internus on the inside. The 
 distance between these two walls is about an eighth of an 
 inch. Its antero-posterior diameter is about one-fifth of an 
 inch. It presents in its circumference three enlargements, 
 called cornua, a superior, an anterior inferior, and a posterior 
 inferior. The semicircular canals open by three orifice's into 
 the posterior inferior cornu, and by two into the superior, while 
 the vestibular scala opens into the anterior inferior cornu. 
 Thus, it will be seen, that the parietes of the vestibule are 
 perforated by six openings of considerable size. Besides 
 these, there are also small foramina for the transmission of 
 filaments of the auditory nerve, and the aqueduct of the ves- 
 tibule opening into its posterior part. The vestibule presents 
 two depressions, an inferior, called ihefovea hemispheric and 
 a superior, called ihefovea elliptica; these are separated by a 
 crest named eminentia pyramidalis. 
 
 The SEMICIRCULAR CANALS, Fig. 41 (i 5), form each about 
 three-fourths of a circle. They are not exactly round tubes, 
 but compressed slightly on the sides. Two of them open into 
 the vestibule by a common orifice. Dilatations occur at three 
 of their orifices; they are called ampullce. These osseous 
 canals are distinguished from each other by their direction 
 and position. Thus, there is a superior vertical, posterior 
 vertical, and a horizontal one. The superior vertical has its 
 convexity upwards; its situation is indicated by a promi- 
 nence on the petrous bone, which is very distinct in the foetus ; 
 its direction is transversely across the bone. The posterior 
 vertical has a direction parallel to the axis of the petrous 
 bone ; its convexity looks upwards and outwards. The hori- 
 zontal canal is convex outwards. It is shorter than the other 
 two. The common orifice is formed by the two vertical canals. 
 
 The COCHLEA, Fig. 41 (i 7), resembles in shape the shell of 
 a snail. Its base is situated at the bottom of the meatus audi- 
 torius internus, while its apex is directed forwards, outwards, 
 
INTERNAL EAR, OR LABYRINTH. 129 
 
 and downwards. It seems to consist of a tube tapering from 
 one end to the other, and coiled two and a half times round 
 
 Fig. 43. 
 
 A HIGHLY MAGNIFIED VIEW OF THE EXTERNAL FACE OF THE BONY LABYRINTH OP 
 
 THE LEFT SIDE, OPENED so AS TO EXPOSE THE VESTIBULE AND ITS CONTENTS, Ac. The 
 difference of color in the shades of this figure is intended to assist in distinguishing 
 the external from the internal faces of the labyrinth, and also the cavities supposed 
 to be occupied by the liquor of Cotunnius. 1. The ampulla of the superior semi- 
 circular canal. 2. The ampulla of the external canal. 3. The ampulla of the 
 inferior canal. 4. The superior membranous semicircular canal. 5. External 
 membranous canal. 6. The inferior membranous canal. 7. The spaces between 
 the bony and membranous semicircular canals, thought to be occupied by the liquor 
 Cotunnii. 8. The common tube formed by the union of the superior and inferior 
 membranous canals. 9. The place where the external semicircular canal opens into 
 the sacculus ellipticus of the vestibule. 10. The sacculus ellipticus containing the 
 otoconia of Breschet, seen at 11. 12. Sacculus sphericus, containing also some 
 otoconia, as seen at 13. 14, 15, 16, 17, 18. The expansions of the auditory nerve to 
 the membranous canals and the sacculus ellipticus, and also to the sphericus. 19. 
 The turns of the lamina spiralis. 20. The scala ty^wpani. 21. The nervous ex- 
 pansion to the posterior ampulla. 22. The scala vestibuli. 23. The modiolus. 
 
 a central column. A partition, Fig. 43 (i 9), passes from the 
 base to the apex in this tube, dividing it into two compart- 
 ments, called scales. One of these scalae opens into the tym- 
 panum, and the 'Other into the vestibule, hence they are 
 named the tympanic and the vestibular scalar. 
 
130 DISSECTION OF THE HEAD AND NECK. 
 
 The septum between the scalae is called the lamina spiralis ; 
 this is partly osseous and partly membranous; it is spoken of 
 as the lamina spiralis membranacea, and the lamina spiralis 
 ossea. The osseous portion is attached by its inner border 
 to the central column, or modiolus, and in the dried prepara- 
 tion looks like the thread of a screw. The upper extremity 
 of this projects slightly from the central column, and forms 
 the hamulus. Both it and the outer or membranous portion 
 consist of two lamellae, between which are placed filaments 
 of the auditory nerve. The osseous lamina is broadest at 
 the base of the cochlea, while the membranous is broadest 
 at the apex. The modiolus is a column of a conical shape, 
 with its base perforated by many small foramina, and traversed 
 by several osseous canals for the transmission of the filaments 
 from the internal meatus, which pass through the interior of 
 this tube to get in between the lamellae of the lamina spiralis. 
 Its apex is somewhat expanded, to which portion of it the term 
 infundibulum is applied ; this again is covered over by what 
 is called the cupola. The modiolus is not a distinct structure, 
 but blended with the inner wall of the tube of the cochlea, 
 and the inner border of the lamina spiralis. The helicotrema 
 is a small opening between the scalae ; it is situated immedi- 
 ately beneath the hamulus. This is the only communication 
 between these semicylindrical tubes. The aqueduct of the 
 cochlea opens into the scala tympani near the fenestra ovalis. 
 
 The different cavities are lined by a very delicate fibro- 
 serous membrane. The fibrous layer adheres closely to the 
 bone, and answers the purpose of a periosteum ; the serous 
 layer secretes the perilymph, or liquor Cotunnii. This lining 
 membrane assists in closing the fenestra rotunda and the 
 fenestra ovalis ; it also forms the lamina spiralis membranosa. 
 
 The MEMBKANOUS LABYEINTH is found only in the vestibule 
 and semicircular canals. The vestibular portion consists of 
 the utriculus, or common sinus, and the sacculus. It is not 
 certainly ascertained whether these two membranous cavities 
 communicate with each other or not. The utriculus occupies 
 the posterior part of the vestibule, and the sacculus the ante- 
 rior and inferior parts. The membranous semicircular canals 
 correspond with the osseous canals in number, in ampullae, 
 and in their openings into the utricle. The membranous 
 labyrinth is filled with a semi-fluid called the endolymph. 
 
INTERNAL EAR, OR LABYRINTH. 131 
 
 There are observed attached to the utricle and saccule 
 small calcareous bodies, called otolithes, or otoconia. 
 
 The arteries of the tympanum enter it in the following 
 manner : A small branch from the middle meningeal passes 
 through the hiatus Fallopii; another from the internal max- 
 illary enters it through the Glaserian fissure; a third one 
 comes from the stylo-mastoid, and gets in at the lower end of 
 the aqueduct of Fallopius; it receives branches through the 
 Eustachian tube from the ascending pharyngeal or inferior 
 palatine arteries ; the internal carotid also sends a twig into 
 it through a small foramen from the carotid canal. 
 
 The artery to supply the labyrinth passes through the 
 meatus auditorius internus. It sometimes comes from the 
 superior cerebellar, and sometimes from the basilar. At the 
 bottom of the meatus it divides into a vestibular and a coch- 
 lear branch. 
 
 The nerves connected with the middle and internal ear are 
 derived from several sources. There are four which enter 
 the petrous bone; one of these terminates in the labyrinth; 
 the other three pass through the bone, traversing in their 
 course the tympanum. The portio dura and portio mollis 
 enter it through the meatus auditorius internus ; the former 
 leaves it through the foramen stylo-mastoideum ; the latter is 
 distributed to the labyrinth. The vidian enters through the 
 hiatus Fallopii, and makes its exit as the chorda tympani, 
 through a small aperture near the Glaserian fissure. Jacob- 
 son's branch of the glosso-pharyngeal passes through a small 
 foramen situated between the jugular fossa and carotid fora- 
 men, and leaves the bone as the superficial petrosal branch of 
 Jacobson, just below the hiatus Fallopii to go to the otic 
 ganglion. 
 
 The PORTIO MOLLIS, Fig. 44 (i 5, i e, 17), at the bottom of 
 the meatus divides into two branches, one for the cochlea and 
 one for the vestibule and semicircular canals. The anterior or 
 cochlear division passes through by a number of filaments the 
 perforated base of the modiolus, and thus enters its osseous 
 canals, from which the filaments enter nearly at right angles 
 the space between the lamellae of the lamina spiralis, to 
 terminate in a delicate nervous membrane in the form of 
 papillae. 
 
 The posterior or vestibular division separates into three fasci- 
 
132 DISSECTION OF THE HEAD AND NECK. 
 
 culi ; the superior of which, enters the vestibule to expand on 
 the utricle and on the ampullae of the superior vertical and 
 
 Fig. 44. 
 
 A VIEW OF THE LABYRINTH IN AN INVERTED POSITION, LAID OPEN so AS TO SHOW 
 THE DISTRIBUTION OF THE NERVES. 1, 2, 3. The cochlea laid open in its fullest ex- 
 tent, so as to show the lamina spiralis. The figures are placed on the two turns and 
 and a half. 4, 5, 6. The remains of the parietes of the cochlea. 7, 8. The vestibule. 
 9, 10. Superior canal. 11, 12. Inferior canal. 13. The external canal. 14. The 
 semicircular membranous canals. 15, 16, 17. The auditory nerve in its course to 
 the labyrinth. 
 
 horizontal membranous semicircular canals; the middle passes 
 through the macula cribrosa to expand on the saccule ; the 
 inferior enters the posterior part of the vestibule to go to the 
 ampulla of the posterior vertical membranous canal. 
 
 The POKTIO DUEA leaves the meatus and enters the aque- 
 duct of Fallopius, passes forwards and outwards to communi- 
 cate with the hiatus Fallopii, where it is joined by the vidian 
 nerve, and presents a ganglionic enlargement ; it then passes 
 backwards and downwards over the fenestra ovalis to reach 
 the foramen stylo-mastoideum. In its course through the 
 tympanum it passes from the upper and anterior part of the 
 inner wall to' the lower and inner part of the posterior wall. 
 It is connected by one or two filaments to the portio mollis. 
 
 The YIDIAN, after passing through the hiatus Fallopii, 
 joins the portio dura and accompanies it through the tym- 
 panum and a short distance into the stylo-mastoid canal, 
 
INTERNAL EAR, OK LABYRINTH. 133 
 
 then leaves it, returns by a bony canal into the tympanum, 
 and goes forwards between the handle of the malleus and 
 long process of the incus, to a small foramen close by the 
 Glaserian fissure. After leaving the portio dura, it is called 
 the chorda tympani. 
 
 The NERVE OF JACOBSON, from the glosso-pharyngeal, 
 enters the tympanum just below the promontory, and after 
 giving off the following branches leaves it through an osseous 
 canal in the upper and anterior part near the hiatus Fallopii : 
 
 Fig. 45. 
 
 A DRAWING OF THE TYMPANIC NERVE FROM BRESCHET'S WORK ON THE EAR. A. 
 Squamous part of temporal bone. B, B. Petrous portion of same. c. Lower maxillary 
 nerve. D. Internal carotid artery, a. Tensor tympani muscle. 1. Carotid plexus. 
 2. Otic ganglion. 3. Glosso-pharyngeal nerve. 4. Tympanic nerve. 5. Branches 
 to carotid plexus. 6. Branch to fenestra rotunda. 7. Branch to fenestra ovalis. 8. 
 Branch to join the large superficial petrosal nerve. 9. Small superficial petrosal 
 nerve. 10. Nerve to tensor tympani muscle. 11. Facial nerve. 12. Chorda tym- 
 pani. 13. Petrous ganglion of the glosso-pharyngeal. 14. Branch to the membrane 
 lining the Eustachian tube. 
 
 One branch enters the carotid canal to join the sympathetic; 
 another joins the vidian in the hiatus Fallopii; a third goes 
 to the Eustachian tube; a fourth to the fenestra ovalis, and a 
 fifth to the fenestra rotunda. By a division of this nerve into 
 12 
 
134 DISSECTION OF THE HEAD AND NECK. 
 
 filaments, and these filaments reuniting, the tympanic plexus 
 is formed. Before entering the tympanum, Jacobson's nerve 
 is connected by filaments with the pneumogastric and facial 
 nerves. This nerve joins the superficial petrosal branch of 
 Jacobson, and thus forms a communication between the gan- 
 glion of the glosso-pharyngeal and the otic ganglion. 
 
 SECT. X. DISSECTION OF THE NOSE. 
 
 The nose is the organ of smell ; it affords to the lungs an 
 external communication which is constantly open for the 
 transmission of air ; it furnishes a passage or common outlet 
 to several cavities lined by mucous membrane ; it also con- 
 tributes essentially to the perfection of the voice. It occu- 
 pies a central position in the facial portion of the head. It 
 has on each side of it the orbit above and the antrum High- 
 mori below, and extends from the floor of the cranial cavity 
 above to the roof of the mouth below. It opens anteriorly 
 upon the face, and posteriorly into the upper part of the 
 pharynx. It is divided into two compartments called the nasal 
 fossae, which are separated by an osseo-cartilaginous septum. 
 
 The term nose is more commonly applied to that portion 
 which projects upon the face. The structure of the lower 
 and most prominent portion of this is cartilaginous, while 
 the upper part is osseous. The muscles, vessels, and nerves 
 of the nose have already been described. 
 
 The bones are the nasal and the nasal processes of the su- 
 perior maxillas. 
 
 The cartilages, or fibro-cartilages, form the framework of 
 the movable part of the nose. They furnish a structure of 
 sufficient firmness to preserve the anterior nares patent, while 
 their mobility is a protection against injury, and allows the 
 nostrils to be closed or expanded. 
 
 These cartilages consist of the septal or middle, and two 
 lateral upon each side, a superior and inferior, or alar. 
 
 The middle cartilage, Fig. 46 (4), forms the anterior septum 
 of the nasal fossae. The columna is the septum between the 
 anterior nares. This cartilage is of an irregular triangular 
 shape ; its centre is not so thick as the margins, and is fre- 
 quently inclined to one side or the other. Its upper and 
 posterior border is attached to the vertical lamella of the 
 
OF THE NOSE. 
 
 135 
 
 Fig. 46. 
 
 ethmoid, and its posterior inferior border is received between 
 the edges of the vomer and the palatine 
 processes of the superior maxillae ; its 
 anterior border is connected to the nasal 
 suture and to the two inferior lateral 
 cartilages. It sometimes projects back- 
 wards between the ethmoidal lamella and 
 the vomer to the rostrum of the sphenoid 
 bone. 
 
 The superior lateral cartilage, Fig. 47 (i), 
 on each side is attached above to the 
 lower border of the nasal bone, poste- 
 riorly to the nasal process of the superior LA ^Es W oF F THE 
 
 maxilla, below to the inferior lateral car- LOOKING INTO THE NOS- 
 
 tilage of the same side, and in the median ^SffSSKSi 
 
 line to the septal cartilage ; the two car- lateral cartilages. 2'. 
 
 tilages are not directly attached to each * nn T er P art of j the * an ! e - 
 
 .-, . . J . rm 4. Lower edge of the 
 
 other at their anterior margins. The cartilage of the septum, 
 anterior margin is thicker than the pos- 
 terior. They are of a triangular shape. The inferior lateral or 
 
 Fig. 47. 
 
 Fig. 48. 
 
 VIEW OF THE BONES AND CARTI- 
 LAGES OF THE OUTER N OSE, FROM THE 
 
 EIGHT SIDE. a. Nasal bone. 6. Nasal 
 process of upper maxillary bone. 1. 
 Right upper lateral cartilage. 2. Lower 
 lateral cartilage, its outer part. 2*. 
 Inner part of the same. 3. Sesamoid 
 cartilages. 
 
 FRONT VIEW OF THE CARTILAGES OF 
 THE NOSE. ABOVE is SEEN THE OUT- 
 LINE OF THE NASAL BONES. a. Front 
 edge of the septal cartilage. b, b. 
 Lateral cartilages, c, c. Alar carti- 
 lages, with their appendages. 
 
136 DISSECTION OF THE HEAD AND NECK. 
 
 alar cartilages, Fig. 48, c, c, nearly surround the anterior nares ; 
 the outer and posterior part of each is narrow, but is en- 
 larged anteriorly to form with its fellow on the opposite side 
 the apex of the nose. Each projects backwards below the 
 septal cartilage to assist in forming the columna. Behind 
 where their outer portions are attached by dense fibrous 
 tissue to the maxilla, are usually on each side two or three 
 small cartilages, called the sesamoid cartilages. The inner 
 portion of each alar cartilage is connected behind to the nasal 
 spine. The lower parts of the alas of the nose are formed by 
 dense areolar tissue. 
 
 The NASAL Foss^: should be studied in the first place in 
 a prepared skull, which has been divided by a vertical sec- 
 tion made a little to one side of the median line, so as to 
 leave the osseous septum entire. A knowledge of the nasal 
 fossae is too important to be neglected by the student. If he 
 be familiar with the osseous walls of these cavities, he will 
 encounter very little difficulty in dissecting and understand- 
 ing the soft parts connected with them. 
 
 Each nasal fossa- is somewhat wedge-shaped ; the thin edge 
 looks upwards, and is rounded off anteriorly and posteriorly, 
 to correspond to the arched roof of this cavity. 
 
 The inner wall, Fig. 49, is formed above by the vertical 
 
 Fig. 49. 
 
 OSSEOUS AND CARTILAGINOUS SEPTUM OF THE NOSE, SEEN FROM THE LEFT 
 SIDE. a. Nasal bone. 6. Superior maxillary bone. c. Sphenoidal sinus, d. 
 Central or perpendicular plate of the ethmoid bone. e. Vomer. 2*. Inner part 
 of the (right) lower lateral cartilage of the nose. 4. Cartilage of the septum. 
 
OF THE NOSE. 137 
 
 lamella of the ethmoid bone ; below and behind by the 
 vomer ; the angular space between these bones anteriorly 
 is occupied by the septal cartilage. The outer wall, Fig. 50, 
 is very uneven on account of the projection of the turbinated 
 bones into the fossa. 
 
 The INFERIOR TURBINATED BONE, Fig. 50 (7), is a separate 
 piece. Its inferior free border is situated about half-way be- 
 tween the superior maxilla and the septum nasi, and about four 
 lines from the floor of the fossa. The distance between its 
 central part, which is more prominent than the extremities, 
 and the septum, is usually less than a fourth of an inch. 
 The space below and between this bone and the nasal wall 
 
 Fig. 50. 
 
 THE OUTER WALL OF THE LEFT NASAL FOSSA COVERED WITH THE PITUITARY 
 MEMBRANE. 1. Frontal bone. 2. Nasal bone. 3. Superior maxillary. 4. Sphe- 
 noid. 5. The upper spongy bono. 6. Middle spongy bone. 7. Lower spongy 
 bone. The three meatuses of the nose are seen below the three last-named bones 
 respectively. 8. The opening of the Eustachian tube. 
 
 of the antrum is the inferior meatus ; the ductus ad nasum 
 opens into the anterior extremity of this meatus. The sur- 
 face of the inferior turbinated bone is very rough, presenting 
 numerous elevations and depressions. Its attachments are 
 slight, consequently it is easily broken away. 
 
 12* 
 
138 DISSECTION OF THE HEAD AND NECK. 
 
 The MIDDLE TURBINATED BONE, Fig. 50 (e), is a part of the 
 ethmoid; and is not half as large as the inferior. This is situated 
 in the lower part of the upper half of the nasal fossa ; its free 
 border is separated from the inferior about two lines. The 
 middle meatus is the space below and on the outside of it. 
 The antrum Highmori, the anterior cells of the ethmoid and 
 the frontal sinus open into this meatus. The frontal sinus 
 is nearly half an inch above and in front of its anterior ex- 
 tremity, and the opening between them is called the infundib- 
 ulum. 
 
 The SUPERIOR TURBINATED BONE, Fig. 50 (s\ is about half 
 an inch in length ; it is separated from the posterior part of 
 the middle turbinated bone by the superior meatus, which is a 
 small sulcus, forming a sort of common opening to the pos- 
 terior cells of the ethmoid. The spheno-palatine foramen is 
 situated just behind this meatus, and the opening from the 
 sphenoidal sinus just behind and above it. Thus it will be 
 seen that the frontal and sphenoidal sinuses, the antrum of 
 the maxilla, the cells of the ethmoid bone and the nasal duct 
 all communicate with the nasal fossa. 
 
 A very small portion of the lachrymal bone is seen in the 
 anterior extremity of the middle meatus. This should be 
 noticed, as showing the relation of the lachrymal sac to the 
 nasal fossa. The vertical lamella of the palatine bone forms 
 a portion of the outer wall posteriorly. 
 
 The ROOF of each of the nasal fossae is arched in its antero- 
 posterior direction. It is formed, proceeding from before 
 backwards, by the nasal bones, the floor of the frontal sinus, 
 the cribriform plate of the ethmoid, and the anterior wall of 
 the sphenoidal sinus. The central or horizontal portion is 
 perforated for the olfactory nerve and the internal nasal branch 
 of the ophthalmic ; the anterior sloping portion has a groove 
 for the nasal branch just mentioned ; the posterior portion, 
 which is nearly vertical, contains the opening from the sphe- 
 noidal sinus. The form of the roof may be modified some- 
 what, according to the development of the frontal and sphe- 
 noidal sinuses. 
 
 The FLOOR of each fossa is nearly horizontal in the antero- 
 posterior direction, and concave transversely; it is narrowest 
 at its anterior extremity. The central part is formed by the 
 horizontal plate or palatine process of the superior maxilla; 
 anteriorly, by the bony substance just above the alveolar pro- 
 
OF THE NOSE. 139 
 
 cess which contains the canine teeth ; and behind, by the hori- 
 zontal plate of the palatine bone. About a fourth of an inch 
 
 Fig. 51. 
 
 A VERTICAL SECTION OF THE MIDDLE PART OF THE NASAL FOSS.E, GIVING A POS- 
 TERIOR VIEW OF THE ARRANGEMENT OF THE ETHMOID AL CELLS, &C. 1. Anterior 
 
 fossa of the cranium. 2. The same covered by the dura mater. 3. The dura inater 
 turned up. 4. The crista galli of the ethmoid bone. 5. Its cribriform plate. 6. 
 Its nasal lamella. 7, 7. The middle spongy bones. 8. The ethmoidal cells. 9. The 
 os planuin. 10. Inferior spongy bone. 11. The vomer. 12. Superior maxillary 
 bone. 13. Its union with the ethmoid. 14. Anterior parietes of the antrum High- 
 morianum, covered by its membrane. 15. Its fibrous layer. 16. Its mucous mem- 
 brane. 17. Palatine process of the superior maxillary bone. 18. Hoof of the 
 mouth covered by the mucous membrane. 19. Section of this membrane. A 
 bristle is seen in the orifice of the antrum Highmorianum. 
 
 behind the nasal spine, and close to the septum nasi, is situ- 
 ated the foramen incisivum, or anterior palatine foramen. 
 
 The relation of the external orifice of the Eustachian tube, 
 Fig. 50 (s), to the nasal cavity, should be noticed in the pre- 
 pared skull, but more particularly in the recent subject, with 
 reference to the introduction of an instrument into it through 
 the nasal fossa. 
 
 To examine the nasal fossae in the recent subject, the head 
 must be divided vertically, as was mentioned in connection 
 with the prepared cranium. A fine saw without any back is 
 best for this purpose. 
 
 The nasal fossae are lined by a mucous membrane, which is 
 continued into the sphenoidal, frontal, and maxillary sinuses, 
 and ethmoidal cells; it is continuous through the lachrymal 
 passages with the conjunctiva; with the mucous membrane of 
 the pharynx and Eustachian tubes through the posterior nares, 
 
140 DISSECTION OF THE HEAD AND NECK. 
 
 and with, the skin through the anterior nares. On the septum 
 and turbinated bones it is soft, thick, and very vascular ; in 
 other places it is blended with the periosteum, and might be 
 called a fibro-mucous membrane. At the lower borders of 
 the turbinated bones it forms quite thick folds; and at the 
 inferior orifice of the nasal duct it forms a fold which has 
 been spoken of as a valve. The spheno-palatine, ethmoidal, 
 and anterior palatine foramina are covered over and con- 
 cealed by it in the fresh preparation. The openings into the 
 different sinuses are considerably diminished in size by it, 
 and the periosteum beneath it. It has a columnar epithelium. 
 In the sinuses, the mucous membrane is thinner, less vascu- 
 lar, and covered by the squamous epithelium. Cilia exist 
 upon its surface, both in the sinuses and nasal fossae. 
 
 The following nerves are found in the nasal fossa. As there 
 are no muscles to be supplied in this cavity, no motor nerves 
 are required. 
 
 The OLFACTOKY, Fig. 52 (s), enters it from above by nume- 
 rous filaments, which descend about an inch on the septum, and 
 to the middle meatus on the outer wall. The filaments form 
 minute plexuses beneath the mucous membrane. The exact 
 manner in which they terminate is not known. By tearing 
 off the mucous membrane, the filaments of the olfactory may 
 be traced to their termination in this structure. It will be 
 seen from the distribution of this nerve, that air loaded with 
 odorous particles must reach the upper part of the nasal ca- 
 vity in order to make an impression on the peripheral expan- 
 sion of the nerve of smell. The olfactory nerve is spread out 
 upon only a very small portion of the entire surface of the 
 nasal fossa. 
 
 The SPHENO-PALATINE NEKVE, Fig. 52 (e), consisting usu- 
 ally of several branches, enters the nasal fossa just behind 
 the superior meatus, through the spheno-palatine foramen. 
 Several small branches, called the external, are distributed to 
 the mucous membrane on the outer wall of the fossa, some 
 filaments reaching the septum ; a much larger branch, called 
 the internal or naso-palatine, crosses over to the septum, and 
 descends first vertically, and then horizontally, to reach the 
 anterior palatine foramen, or foramen incisivum, in which it 
 is said to connect with the ganglion of Cloquet, Fig. 52 (9) ; it 
 
OF THE NOSE. 141 
 
 then passes through this foramen to the mucous membrane 
 of the hard palate, just behind the incisor teeth. 
 
 Fig. 52. 
 
 A VIEW OF THE FIRST PAIR OR OLFACTORY NERVES, WITH THE NASAL BRANCHES 
 OF THE FIFTH PAIR. 1. Frontal sinus. 2. Sphenoidal sinus. 3. Hard palate. 4. 
 Bulb of the olfactory nerve. 5. Branches of the olfactory nerve on the superior 
 and middle turbinated bones. 6. Spheno-palatine nerves from the second branch 
 of the fifth pair. 7. Internal nasal nerve from the first branch of the fifth. 8. 
 Branches of 7 to the Schneiderian membrane. 9. Ganglion of Cloquet in the fora- 
 men incisivum. 10. Anastomosis of the branches of the fifth pair on the inferior 
 turbinated bone. 
 
 These nerves ramify between the mucous membrane and 
 periosteum. To obtain a distinct view of them, the part 
 should be kept for some time in dilute nitric acid ; when, by 
 separating the membrane from the bone, they can be seen 
 from the fibrous surface. 
 
 The anterior palatine nerve gives off a branch which enters 
 the nasal fossa near the posterior extremity of the inferior 
 turbinated bone, and ramifies in the lower part of the fossa. 
 
 The internal nasal branch, Fig. 52 (7), of the ophthalmic, 
 enters the nasal cavity through the anterior part of the eth- 
 moid, near the crista galli, sends some twigs to the septum 
 and outer wall, and then passes down on the inner surface of 
 the nasal bone to its junction with the lateral cartilages of the 
 nose, where it perforates the fibrous structure connecting the 
 cartilage and bone, and is distributed to the integument cover- 
 ing the nose. In its course, some filaments penetrate the bone. 
 
 The arteries entering the nasal fossa consist of branches 
 from the spheno-palatine, the infra-orbital, the palatine, the 
 
142 DISSECTION OF THE HEAD AND NECK. 
 
 pterygopalatine, the supra-orbital, the ethmoidal, and the 
 facial. From these various sources the mucous membrane of 
 the nasal fossa is abundantly supplied with arterial blood. 
 
 The veins, Fig. 8, &, correspond with the arteries. Some 
 branches find their way into the frontal sinus, and through 
 the foramen caecum communicate with the superior longitudi- 
 nal sinus of the dura mater. 
 
 The student should study the nasal fossae with reference to 
 plugging the nares to arrest hemorrhage; the removal of 
 polypi, and foreign bodies which may happen to be lodged in 
 them; the introduction of instruments to reach the Eustachian 
 tube, or to be conducted into the pharynx through the nasal 
 cavity; their proximity to the brain and its meninges; and 
 their connection with the sphenoidal, frontal, and maxillary 
 sinuses, Fig. 52 (i, 2), and the ductus ad nasum. The exact 
 relation of the osseous sinuses, just mentioned, to the nasal 
 fossae should be carefully noted ; the manner in which a puru- 
 lent collection in either of these sinuses would be affected, in 
 regard to its escape, by the position of the head. 
 
 If, for instance, pus should be formed in the maxillary 
 sinus or antrum, a large proportion of it would necessarily 
 be retained as long as the head was kept in a vertical posi- 
 tion, on account of the opening from it into the middle mea- 
 tus being situated in the upper part of its nasal wall ; nor 
 could it be emptied of its contents until the head was placed 
 upon the opposite side. In case of a purulent discharge from 
 the nose, a knowledge of this fact would enable the physician 
 to determine whether it came from the antrum or not. 
 
 The contents of the sphenoidal sinus, in case of a purulent 
 collection, would be emptied entirely only when the head was 
 placed with the face looking directly downwards. As the 
 opening from the frontal sinus is in its floor, its contents 
 would escape when the head occupied a vertical position. 
 The nasal orifice of the ductus ad nasum should be observed, 
 and the introduction of a probe of the proper curve into it 
 should be practised upon the subject. The same thing should 
 be done with the antrurn and Eustachian tube. 
 
 A correct idea of the dimensions of the nasal fossa is ex- 
 ceedingly important. It will be observed that the upper part 
 of it is very narrow, and will not admit an instrument of 
 much size without injuring the parietes. 
 
 The walls of the antrum, Fig. 51 (i 4), should be noticed as 
 
TOPOGKAPHY OF THE MOUTH. 143 
 
 regards their thickness, and their relation to the mouth, the 
 nose, the orbit, the pterygo-maxillary fossa, and the face. 
 
 The frontal sinus also demands attention, with reference to 
 diagnosis, in diseases and injuries of it, and the proper treat- 
 ment to be instituted, whether medical or surgical. 
 
 Before dissecting the tongue, soft palate, pharynx, and 
 larynx, the student should carefully examine the topography 
 of the mouth, the fauces, and the pharynx. For this purpose, 
 the head must be divided vertically, a little to one side of the 
 median line, so as to avoid injuring the septum of the nose, 
 as before directed, and at the same time leave the uvula 
 entire. The back of the neck should be dissected before this 
 section is made, in order that the upper cervical vertebrae 
 may be divided with the head. It will not be necessary to 
 divide the tongue or the larynx. The pharynx, however, 
 should be opened along the median line posteriorly. 
 
 SECT. XI. TOPOGRAPHY OF THE MOUTH, FAUCES, AND 
 PHAKYNX. 
 
 The MOUTH is the first division of the alimentary canal. 
 It is exceedingly important, on account of the several func- 
 tions with which it is associated. The organ of taste is located 
 here ; the processes of mastication, insalivation, the articula- 
 tion of sounds, and the commencement of deglutition, all 
 take place in the cavity of the mouth. It is surrounded by 
 movable walls, except the upper, and consequently is subject 
 to great variation in its dimensions. When the lower jaw is 
 applied to the upper, it is divided into two cavities ; the outer 
 one is situated between the cheeks and lips, and the teeth and 
 alveolar processes; the inner one is embraced within the cir- 
 cumference of the teeth and alveoli. The former receives the 
 saliva secreted by the parotid glands ; while that secreted by 
 the submaxillary and sublingual is poured into the latter, thus 
 securing a proper intermixture of the saliva with the food. 
 The external orifice of the mouth opens into the one, and the 
 internal orifice opens out of the other into the fauces. The 
 food is kept between the teeth until properly masticated, by 
 the action of the lips and cheeks on the outside, and the 
 
144 DISSECTION OF THE HEAD AND NECK. 
 
 tongue on the inside of them. The lips are active agents in 
 receiving food into the mouth, and the tongue is concerned 
 in forcing it back into the pharynx. 
 
 Both cavities are lined by mucous membrane, which is 
 worthy of particular attention, as presented on the upper 
 surface of the tongue, on the alveoli and hard palate, and 
 in the other parts of the mouth. 
 
 The LIPS are composed of the following structures : The 
 orbicularis oris forms the middle and larger portion of their 
 bulk ; it is covered on the outside by skin and subcutaneous 
 areolar tissue; and, on the inside, by mucous membrane and 
 submucous areolar tissue. They are abundantly supplied 
 with arteries and nerves. The labial glands are situated on 
 their inner side. The lips never contain adipose tissue. 
 Their great size in the African is owing mainly to the size 
 of the orbicular muscle. 
 
 The free borders of the lips in a state of health are of a 
 bright red color ; but in an anaemic condition of the system, 
 or when the blood recedes from the cutaneous capillaries, 
 they present a pale appearance. The study of the lips is 
 very interesting and important to the artist, as they have so 
 much to do in giving expression to the countenance. 
 
 The CHEEKS are composed of the same elements as the 
 lips ; besides, they usually contain more or less adipose sub- 
 stance. The principal muscle in each cheek is the bucci- 
 nator. It is perforated opposite the second upper molar 
 tooth by the duct of the parotid. Besides the small buccal 
 glands beneath the mucous membrane, there are two quite 
 large ones situated between the masseter and buccinator 
 muscles ; these are called the molar glands. 
 
 The fulness or plumpness of the cheeks depends partly on 
 the fat which they contain, and partly on the presence of the 
 teeth. The mucous membrane of the lips and cheeks is re- 
 flected upon the alveolar processes, where it is blended with 
 the fibrous structure beneath. It is here thick and dense, 
 and possesses very little sensibility, as shown in infants, and 
 in old people who have lost their teeth. It connects on the 
 two sides of the alveolus, between the teeth and over the 
 interalveolar septa. The gums are supplied with mucous 
 follicles. Tartar, as it is called, is a product of these follicles. 
 
TOPOGRAPHY OF THE MOUTH. 145 
 
 The mucous membrane forms a fold on the inner side of 
 each lip, which is called fraemim labii. 
 
 In the posterior division of the buccal cavity, the mucous 
 membrane and the papillas of the tongue are the principal 
 things now to be examined. The portion covering the hard 
 palate is similar to that of the gums. It is rough and uneven. 
 Between it and the bone ramify vessels and nerves. It covers 
 over and conceals the anterior and posterior palatine fora- 
 mina. Between the alveolar processes of the lower jaw and 
 the free border of the tongue it is thin, and loosely connected 
 to the subjacent tissues. In the median line and on the un- 
 der surface of the tongue it presents a fold, called ihefrcenum 
 lingucB. This is so large and unyielding in some cases, that 
 it interferes with the movements of the tongue. The diffi- 
 culty is removed by dividing its free border. Just behind the 
 incisor teeth, Fig. 53 (3), the mucous membrane is perforated 
 
 Fig. 53. 
 
 A VIEW OF THE LOWER JAW, WITH THE TONGUE DRAWN UPWARDS, so AS TO 
 SHOW ITS UNDER SURFACE IN SITU. 1, 2. The posterior superior surface of the 
 tongue, with the papillae maximae. 3. The opening of the duct of the subinaxillary 
 gland, or the duct of Wharton. 4. The sublingual gland, seen under the mucous 
 membrane of the mouth. 5. The lower jaw. 
 
 by the excretory ducts of the sublingual and submaxillary 
 glands. The upper surface of the tongue is studded with 
 papillae, Fig. 54, which render it quite rough. There are 
 two kinds of these papillae. One set is perforated, and the 
 other is not. The former are situated near the base of the 
 13 
 
146 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 tongue, and are of a glandular structure. They are arranged 
 in two rows. The mucous membrane 
 Fig. 54. i s n ot closely adherent to them, as it 
 
 is to the true papillae. 
 
 The true papillae are divided into 
 three classes, as follows : 
 
 The calyciform consist of two rows 
 which are arranged in the form of 
 the letter V. There are from six 
 to eight in each row. They are situ- 
 ated on the posterior part of the 
 tongue. Each papilla is attached to 
 the centre of a cup-like depression 
 by its small extremity, leaving its 
 large extremity free, and on a level 
 with the surface of the tongue. At 
 the junction of the two rows behind 
 is a deep depression, called the " fora- 
 men caecum." It has opening into 
 it several mucous follicles. Some- 
 times a papilla is found in the place 
 of it. 
 
 The fungiform are found near the 
 s ^ es an ^ t j p o f fa Q tongue. They 
 
 in some tongues bifurcates on ^ , . , , / 
 
 the dorsum of the organ, as are ot a reddish color, and much 
 in the figure. 2,2. The lobes smaller than the preceding. They 
 
 of the tongue. The rounded -\ , T i i j 
 
 eminences on this part of the & TQ best seen when a sapid substance 
 organ, and near its tip, are is applied to the living tongue, as they 
 
 the papillae fungiforraes. The 
 smaller papillse, among which 
 the former are dispersed, are 
 
 the papillae come*, and fiH- over 
 
 formes. 3. The tip of the _ , 
 
 tongue. 4, 4. its sides, on ot the tongue. 
 
 THE TONGUE, WITH ITS PA- 
 PILLAE. 1. The raphe", which 
 
 hppornp 
 , '1*16 
 
 The COniCOL pctpillce are diffused 
 
 greater part of the dorsum 
 
 .. 
 
 They are inclined 
 
 which are seen the lamellated backwards, which becomes Very ap- 
 
 and fringed papillae. 5, 5. 1,1 i_i i 
 
 The y-shaped row of papilla parent when the tongue is rubbed 
 
 caiyciformes. 6. The fora- from behind forwards, especially in 
 
 Te lower animals. 
 
 tongue. 
 
 the os hyoides. 
 
 r oo, . They are 
 
 8. The epiglottis, of a whiter color than the others. 
 
 are supplied with filaments from the 
 fifth and glosso-pharyngeal nerves. 
 
 The FAUCES, Fig. 55, is the space between the mouth and 
 
TOPOGRAPHY OF THE FAUCES. 
 
 147 
 
 the pharynx. It is bounded above by the soft palate, on 
 each side by the anterior and posterior half-arches of 
 
 Fig. 55. 
 
 MEDIAN SECTION OP THE NOSE, MOUTH, PHARYNX, AND LARYNX. a. Septum of 
 the nose; below it is the section of the hard palate. 6. The tongue, c. Section of 
 velum pendulum palati. d, d. Lips. u. Uvula, r. Anterior half-arch or pillar of 
 fauces, t. Posterior half-arch, t. Tonsil, p. Pharynx, h. Hyoid bone. k. Thy- 
 roid cartilage, n. Cricoid cartilage. . Epiglottis, v. Glottis. 1. Posterior 
 opening of nares. 3. Fauces. 4. Superior opening of larynx. 5. Passage into 
 oesophagus. 6. Mouth of right Eustachian tube. 
 
 the palate and the amygdaloid fossa, which contains the 
 tonsil, and below by the base of the tongue. Its parietes are 
 all movable, and contain muscular structure. The anterior 
 half-arch. Fig. 55, r, on each side is formed by the palato-glossus 
 muscle and the mucous membrane reflected around it. It has 
 nearly a vertical direction transversely. The posterior half- 
 arch, Fig. 55, i, is formed by the palato-pharyngeus muscle. Its 
 direction is downwards, backwards, and outwards. It pro- 
 jects inwards more than the anterior. Between these half- 
 arches is the amygdaloid fossa. It is of a triangular shape 
 with the apex above. The lower part or base of it corre- 
 sponds very nearly with the angle of the lower jaw. Its 
 
148 DISSECTION OF THE HEAD AND NECK. 
 
 outer wall is formed by the superior constrictor of the pha- 
 rynx and the pharyngeal aponeurosis, by which the excava- 
 tion containing the tonsil is separated from the internal 
 carotid artery. 
 
 The tonsil, Fig. 55, t, is composed of a number of follicles col- 
 lected into a group. Its internal surface is perforated by fora- 
 mina which communicate with these follicles. A single fora- 
 men may open into a cell or cavity with which several 
 follicles communicate. In excising the tonsil when enlarged, 
 there can be no danger of wounding the internal carotid if 
 the incision be not made deeper than on a level with the half- 
 arches. Nor is there any danger of injuring the same artery 
 in opening abscesses of the tonsil if the bistoury be not car- 
 ried into it too far in a posterior direction, as the artery lies 
 outside and between the tonsil and the vertebra, on the 
 rectus capitis anticus major. Abscesses of the tonsil almost 
 always open internally on account of the resistance offered 
 by the pharyngeal aponeurosis. Mucus sometimes collects 
 and becomes inspissated in the follicles, and when discharged 
 gives rise to the idea that tuberculous matter has been expec- 
 torated. The tonsil is supplied principally by the palatine 
 branches of the pharyngeal arteries. These arteries some- 
 times attain a considerable size in enlargements of the tonsils, 
 and consequently may give rise to quite a profuse hemor- 
 rhage when they are excised. 
 
 The PHARYNX, Fig. 55, p, is the third division of the ali- 
 mentary canal. It extends from the cuneiform process of 
 the occipital bone to a point opposite the fifth cervical verte- 
 bra. It communicates with the tympana, nasal fossae, mouth, 
 larynx, and oesophagus. Its position and relation to con- 
 tiguous parts render an accurate knowledge of it exceedingly 
 important. It may be very properly considered as divided 
 into a nasal, a faucial, and a laryngeal section. This division 
 is not based upon its structure, but upon its relations to the 
 parts placed in front of it. Its posterior wall corresponds to 
 the bodies of the superior five cervical vertebras. This pre- 
 sents nothing which requires to be noticed at the present 
 time. The same is true with the lateral walls, except at the 
 upper part, where the orifices of the Eustachian tubes are 
 found. The pharynx has no anterior wall peculiar to itself, 
 but is intimately associated with the nasal cavities, the fauces, 
 and the larynx. 
 
TOPOGKAPHY OF THE PHAKYNX. 149 
 
 The posterior nares open into its upper part in a vertical 
 direction. They are each about an inch in height, half an 
 inch in breadth, and about three-fourths of an inch from the 
 posterior wall of the pharynx ; their surface is smooth, and 
 they are slightly expanded, which facilitates the introduction of 
 a plug, when this becomes necessary to arrest hemorrhage, and 
 at the same time allows the plug to slip back into the pha- 
 rynx, unless it be retained by the proper means in situ. It 
 will be observed that in plugging the posterior nares, unless 
 the plug be adapted to their shape, the lower part of the ori- 
 fice may be closed while the upper part will be left open. 
 
 The pharyngeal orifice of each Eustachian tube will be seen 
 a short distance behind, and to the outside of the nasal orifice. 
 It is on a plane about one-fourth of an inch above the floor 
 of the nasal fossa. It is somewhat expanded in the shape of 
 a funnel, which readily admits a probe, or a tube for injecting 
 the tympanum. Quite a deep sulcus in the upper and outer 
 part of the pharynx should be noticed. It is just behind, 
 and separated from the Eustachian orifice by a ridge. 
 
 The SOFT PALATE and the UVULA, Eig. 55, c, w, projecting 
 from the centre of its free border, may now be examined. It is 
 a muscular organ, firmly attached to the posterior margin of 
 the hard palate, and projecting backwards and downwards into 
 the pharynx ; it serves to extend the floor of the nasal fossa3 
 and roof of the mouth in this direction. It diminishes in 
 thickness from before backwards, and assumes an arched 
 form, with the concavity looking downwards and forwards. 
 When elevated, it has a horizontal direction, and its free 
 border is applied to the posterior wall of the pharynx, so as 
 to form a septum between its upper and two lower divisions. 
 The palate is marked on both of its surfaces in the middle by 
 a whitish line or raphe. 
 
 The UVULA has a conical shape, varies very much in size, 
 and consists principally of mucous membrane and areolar 
 tissue, with a few longitudinal muscular fibres. It is pendu- 
 lous, and, when not enlarged, its tip nearly touches the 
 tongue, near the foramen caecum. Its areolar tissue is lia- 
 ble to be filled with serum in inflammation of the throat, 
 causing it to rest upon the tongue, and thus giving rise to a 
 sense of titillation. Its weight, in these cases, may have a 
 tendency to draw down the soft palate. 
 
 13* 
 
150 DISSECTION OF THE HEAD AND NECK. 
 
 At the lower part of the faucial opening in the pharynx, 
 are two fossae or depressions, situated between the root of the 
 tongue and the epiglottis, and separated from each other by a 
 fold of mucous membrane, called frsenum epiglottidis. These 
 fossae are sometimes quite deep, and allow small bodies to 
 lodge in them, which may give rise to irritation and spasmo- 
 dic cough. 
 
 In the anterior part of the laryngeal portion of the pharynx 
 will be noticed the epiglottis, glottis, greater cornua of the 
 hyoid bone, posterior borders of the alae of the thyroid car- 
 tilage, arytenoid, and cricoid cartilages. The exact location 
 of each of these bodies is deserving of particular notice. 
 They will be considered separately in connection with the 
 larynx. The hyoid bone seems to belong both to the tongue 
 and the larynx. It will be described with the latter. 
 
 Before leaving the cavities just described, it would be well 
 for the student to study them carefully in their relations to 
 each other, as in reference to introducing the stomach tube, 
 extracting foreign bodies from the pharynx or oesophagus, 
 carrying an instrument into the larynx, either through the 
 mouth or nose, opening abscesses in the pharynx, removing 
 polypi or tumors about the posterior nares, &c. 
 
 SECT. XII. DISSECTION OF THE PALATE. 
 
 The soft palate contains five pairs of muscles. These are 
 exposed, and their arrangement seen by very little dissec- 
 tion, which may be done after the removal of the pharynx. 
 
 The palatine aponeurosis is a fibrous prolongation from the 
 posterior margin of the hard palate. It diminishes in thick- 
 ness as it descends towards the free border. It is connected 
 with the tendons of the palatine muscles, and forms a sort of 
 framework for the palate. 
 
 The AZYGOS UVUL^, Fig. 57 (a), consists of two vertical 
 fasciculi, which arise from the centre of the free border of 
 the hard palate, and extend to the tip of the uvula. In ex- 
 cising the uvula, the mucous membrane should not be made 
 tense; if it be done, the fibres of this muscle may project 
 from the wound after the membrane has retracted. 
 
 The LEVATOR PALATI, Fig. 56 (2, *), consists of a vertical 
 
DISSECTION OF THE PALATE. 
 
 151 
 
 and a horizontal portion. The vertical part is situated behind 
 the Eustachian tube, and outside the corresponding posterior 
 naris. It arises from the petrous portion of the temporal 
 bone, near its apex, and from the contiguous part of the 
 Eustachian tube. Its fibres pass downwards, on the outside 
 of the tube, and then turn inwards to be inserted, with its 
 fellow, on the opposite side, along the median line of the 
 palate. 
 
 The TENSOK PAL ATI arises, Fig. 56 (4), from the scaphoid 
 fossa at the upper part of the internal pterygoid ala, from a 
 small portion of the great wing of the sphenoid, and from the 
 Eustachian tube. Its fibres pass downwards to the hamular 
 process, where they form a small round tendon, which winds 
 round this process, and is reflected horizontally to the me- 
 dian line of the palate, into which it is inserted. Where it 
 plays over the pully-like surface of the hamular process, 
 there is a synovial membrane. Its vertical portion is situated 
 between the internal pterygoid and levator palati muscles. 
 
 Fig. 56. 
 
 7 83 
 
 Fig. 57. 
 
 
 A VIEW OF THE MUSCLES OF THE 
 SOFT PALATE, AS SEEN FROM BELOW 
 AND IN FRONT. 1. The roof of the 
 mouth, or hard palate, sawed across at 
 the second molar tooth. 2. Origin of 
 the levator palati muscle. 3. Its ex- 
 pansion near its insertion. 4. Origin 
 of the circurnflexus or tensor palati. 
 
 5. The pterygo-maxillary ligament, 
 which converts the notch through which 
 this muscle plays into a foramen. 6, 
 
 6. Palatine aponeuropis. 7. A section 
 of the constrictor pharyngis superior 
 muscle. 8. Extremity of the azygos 
 uvulfe muscle. 9. Section of the Eus- 
 tachian tube. 
 
 A POSTERIOR VIEW OF THE MUSCLES 
 OF THE SOFT PALATE, AS SHOWN BY A 
 SECTION OF THE CRANIUM THROUGH THE 
 GLENOID CAVITIES. 1. Basilar portion 
 of the sphenoid bone. 2. Condyles of 
 lower jaw. 3. Hard palate. 4. Levator 
 palati, on one side entire, on the other 
 partially removed. 5, 5. Eustachian tubes. 
 6. External pterygoid muscle. 7. Cir- 
 cumflexus palati. 8. Azygos uvulae. 9. 
 Myloid attachment of constrictor pharyngis 
 superior. 10. Palato-pharyngeus. 11. 
 Palato-glossus. 
 
 The PALATO-GLOSSUS, Fig. 57 (i i), is a small, pale fasciculus, 
 which is spread out above in the soft palate and below in 
 
152 DISSECTION OF THE HEAD AND NECK. 
 
 the side of the tongue. Its middle portion forms the anterior 
 half arch of the palate. It is situated immediately beneath 
 the mucous membrane. 
 
 The palato-pharyngeus, Fig. 57 (i o), is described with the 
 muscles of the pharynx. 
 
 The arteries of the soft palate, or velum palati, are branches 
 of the superior and inferior pharyngeal, and of the internal 
 maxillary. 
 
 The nerves are derived from the ganglion of Meckel, and 
 from the glosso-pharyngeal. 
 
 The cartilaginous portion of the Eustachian tube may now 
 be dissected. This tube, altogether, is about two inches in 
 length. It establishes an open communication between the 
 tympanum and pharynx. Its direction being downwards, 
 forwards, and inwards, facilitates the escape of mucus from 
 the tympanic cavity into the pharynx. The cartilaginous 
 portion is about sixteen lines in length. It is much smaller 
 where it unites with the osseous portion of the tube than at 
 its pharyngeal orifice. It is attached to the sides of the groove 
 formed by the petrous and spinous portions of the temporal 
 and sphenoid bones. The outer and anterior part of the tube 
 consists of a fibrous structure. The mucous lining of the 
 tube is quite delicate, except at its orifice, where it resembles 
 that of the pharynx. The position and large size of this 
 opening deserve particular notice, with reference to the in- 
 troduction of instruments. 
 
 SECT. XIII. DISSECTION OF THE TONGUE. 
 
 The TONGUE is a muscular organ, capable of being moved 
 in different directions, and of varying its form and dimensions. 
 Divided in the median line, it presents two halves in every 
 respect alike. It does not entirely fill the space within the 
 curve of the teeth and alveolar processes. It diminishes in 
 thickness from behind forwards. The anterior part of it is 
 covered wholly by mucous membrane, and not only moves 
 freely in the mouth, but can be protruded from it. The 
 mucous membrane, with the papilla, were described with the 
 topography of the mouth. 
 
 The framework of the tongue consists of the hyoid bone, 
 a hard cartilaginous substance situated in the median line, 
 
DISSECTION OF THE TONGUE. 
 
 153 
 
 and a dense fibrous layer beneath the mucous membrane 
 of the dorsum. Fig. 58. 
 
 The INTRINSIC MUSCLES of the tongue consist of muscular 
 fibres having a longitudinal, transverse, and vertical direc- 
 tion. The longitudinal fibres are situated near its upper and 
 
 Fig. 58. 
 
 A VlEW OP THE DORSUM OF THE 
 TONGUE, FROM WHICH, BY MACERATION, 
 THE PERIGLOTTIS HAS BEEN REMOVED, 
 AND TURNED BACK ON THE RlGHT SlDE. 
 1. The side of the tongue. 2. Its 
 base. 3. Its tip or point. 4. The de- 
 nuded portion of the tongue, showing 
 the papillae deprived of the epidermis 
 or periglottis. 5. The under surface of 
 the detached epidermis, showing its 
 depressions. 6. Foramen Caecum. 7. 
 The truncated papillae near it.. 8. The 
 other papillae, denuded of the epidermis. 
 9. Impression of the periglottis around 
 the denuded papillae. 10. Fraenum to 
 the epiglottis cartilage. 11, 12. De- 
 pressions on the periglottis which fits 
 the elevations on the tongue. 
 
 Fig. 59. 
 
 A VIEW OF THE MUSCLES OF THE 
 TONGUE, AS SEEN ON ITS LOWER SUR- 
 FACE. 1. Body of the os hyoides. 2, 2. 
 Styloid processes of the temporal bones. 
 3. Horizontal portion of the stylo-glossus 
 muscle. 4. The hyo-glossus. 5. The 
 genio-hyo-glossus held up by a hook 
 near its origin. 6. Section of the glos- 
 sal portion of the same muscle. 7. Its 
 insertion into the os byoides. 8. The 
 middle fissure and fatty matter between 
 the muscles of each side. 9. The lingu- 
 alis muscle. 10. The transversales lin- 
 guae at the point of the tongue. 
 
 lower surfaces, and have been called the superior and in- 
 ferior lingual muscles. Fig. 5$ (9). Their origin and termina- 
 tion are not very distinct. The transverse, Fig. 59 (i o), and 
 vertical fibres are seen throughout the substance of the 
 tongue ; the former passing from one side to the other, and 
 the latter from the dorsal to the under surface. 
 
 The extrinsic muscles are those which have their origin 
 outside of the body the tongue. They are the following : 
 
154 
 
 DISSECTION OF THE HEAD AND NECK. 
 
 Fig. 60. 
 
 The STYLO-GLOSSUS, Fig. 59 (s), arises from the styloid pro- 
 cess and stylo-maxillary ligament, and, passing downwards, 
 inwards, and forwards, enters the side of the tongue, where it 
 spreads out and divides into an internal and external portion. 
 The latter runs to the apex, while the former takes a trans- 
 verse direction, and terminates by intermixing with the in- 
 trinsic fibres. 
 
 The HYO-GLOSSUS, Fig. 59 (4), arises from the body and 
 great cornu of the hyoid bone, and enters the tongue between 
 the lingualis and stylo-glossus. The greater part of this 
 muscle is seen in the dissection of the submaxillary region. 
 
 The GrENio-HYO-GLOssus, Fig. 60 (4), is the largest of the lin- 
 gual muscles. It arises from the lower 
 jaw, near the symphysis. Some of its 
 fibres pass downwards and backwards, 
 and are inserted into the hyoid bone. 
 The rest of the fibres, with the excep- 
 tion of a few which spread out upon the 
 side of the pharynx, go to the tongue. 
 They have a vertical direction, and 
 extend the whole length of the tongue 
 near the median line, spreading out 
 in the shape of a fan. At the base 
 of the tongue, the genio-hyo-glossi 
 muscles are separated from each other 
 merely by cellulo-adipose substance. 
 Thepalato-glossus was noticed in the 
 dissection of the palate. 
 
 The arteries of the tongue are, the 
 lingual and branches of the palatine 
 and pharyngeal. The lingual, in the 
 latter part of its course, is called the 
 ranine artery. The sublingual, com- 
 monly a branch of the lingual, passes 
 between the mylo-hyoideus and genio- 
 hyo-glossus muscles, and sends 
 branches to the sublingual gland and 
 to the fraenum linguae. Branches 
 proceed from the lingual artery to every part of the sub- 
 stance of the tongue. 
 
 The nerves are supplied from the hypoglossal, glosso-pha- 
 ryngeal, and the gustatory branch of the fifth. The hypo- 
 
 A VIEW OP THE UNDER 
 SURFACE OF THE TONGUE, 
 WITH THE MUSCLES CONNECT- 
 ED WITH IT. 1, 1. The infe- 
 rior surface of the tongue. 
 2. The os hyoides. 3, 3. Ori- 
 gin of the hyo-glossus muscle. 
 4, 4. The genio-hyo-glossus 
 of each side dissected off and 
 turned to one side. 5, 5. The 
 white central vertical septum 
 of the tongue. 
 
SUPERFICIAL PARTS OF THE NECK. 155 
 
 glossal is distributed to the muscles ; the glosso-pharyngeal 
 to the mucous membrane at the back part of the tongue; 
 and the gustatory branch of the fifth to the mucous mem- 
 brane on its sides and tip. 
 
 CHAPTER II. 
 
 DISSECTION OF THE NECK. 
 
 SECT. I. SUPERFICIAL PARTS OF THE NECK. 
 
 THE posterior part of the .neck should be dissected with 
 the back, as they have several muscles in common, and also 
 on account of the similarity in the arrangement of their ves- 
 sels and nerves. 
 
 The anterior part of the neck is a very important region, 
 and demands the special attention of the student in the dis- 
 secting-room. In it are found the larynx, trachea, pharynx, 
 oesophagus, and numerous vessels and nerves. 
 
 Each side is bounded above by the base of the inferior 
 maxilla, the lower border of the parotid region, and the 
 mastoid process of the temporal bone ; posteriorly, by a line 
 extending from the occiput, just behind the mastoid process, 
 to the acrornion process of the scapula; and below, by the 
 acromion process and the upper border of the clavicle and 
 sternum. The two sides are divided by the median line. 
 One side should be dissected at a time. 
 
 To dissect this region, the thorax should be elevated and 
 the position of the head changed from time -to time, as it may 
 be found necessary to have the parts relaxed or made tense. 
 The dissector must exercise his own judgment in determining 
 the best position for the head in the different stages of the 
 dissection. As a general rule, muscles should be made tense 
 to facilitate their dissection, but sometimes, in separating 
 them from each other, or when tracing vessels and nerves 
 among them, it is better that they should be relaxed, so that 
 they can be drawn to one side or lifted up. 
 
 Before commencing the dissection, the student should ob- 
 
156 DISSECTION OF THE NECK. 
 
 serve the following prominent points in the median line, and 
 the distances they are apart: The chin, the hyoid bone, the 
 thyroid and cricoid cartilages, and the sternum. If the sub- 
 ject be emaciated, he will also be able to feel distinctly the 
 cartilaginous rings of the trachea. It is an excellent plan 
 for the student to familiarize himself with all the prominent 
 points in a region which can be seen or felt in the living 
 body. If they be movable, then he should attentively ob- 
 serve the changes effected by such movements in their rela- 
 tions to each other and to the surrounding parts. 
 
 A vertical incision is to be made along the median line, 
 through the skin, from the symphysis of the chin to the 
 upper border of the sternum ; and, if the face and thorax 
 have not already been dissected, two horizontal ones will be 
 required ; a superior one, extending from the commencement 
 of the first, along the base of the inferior maxilla, to the 
 mastoid process; and an inferior one, commencing at the 
 termination of the first, and continued along the upper border 
 of the clavicle, to the acromion process. In making these in- 
 cisions, care should be taken to divide nothing but the skin. 
 
 The skin is to be carefully dissected up and reflected back- 
 wards, leaving the superficial fascia exposed. The platysma 
 myoides is placed between two layers of this fascia. The outer 
 layer is very thin in the lower part of the neck, but quite 
 thick in the upper part, where it usually contains a consider- 
 able quantity of adipose tissue. When the fat is very abund- 
 ant, it forms what is called the double chin. There are no 
 vessels of any importance in this layer, and the only nerves 
 found in it are cutaneous branches derived from the cervical 
 plexus. This layer may now be removed, and the platysma 
 myoides exposed. 
 
 To raise the fascia, the student should commence at the 
 chin, and cut down cautiously until he perceives the muscle 
 and observes the direction of its fibres. Having found the 
 muscle, and made its fibres tense by placing the head in a 
 proper position, there can be no difficulty in dissecting off 
 the fascia and leaving the muscle clearly exposed. The 
 strokes of the scalpel must be made, at first slowly and care- 
 fully, in the direction of the fibres. If the student attempts 
 to make a rapid dissection of this muscle, he will be very 
 likely to remove more or less of it with the fascia. 
 
SUPERFICIAL PARTS OF THE NECK. 
 
 157 
 
 The PLATYSMA MYOIDES arises, Fig. 61 (i 4), from the pec- 
 toral and deltoid fascias, just below the clavicle. Its fibres 
 
 Fig. 61. 
 
 A SIDE VIEW OF THE SUPERFICIAL LAYER OF MUSCLES ON THE FACE AND NECK. 
 1. Tendon of the occipito-frontalis. 2. Its frontal belly. 3. Attrahens aurera. 
 4. Attollens aurem. 5. Occipital belly of the occipito-frontalis. 6. Retrahens 
 aurem. 7. Orbicularis palpebrarum. 8, 8. Levator labii superioris alseque nasi. 
 9. Compressor naris. 10. Levator anguli oris. 11. Buccinator. 12. Zygoniaticus 
 minor. 13. Orbicularis oris and zygomaticus major. 14. Platysma myoides. 15. 
 Splenius. 16. Masseter. 17. Sterno-cleido-mastoid. 18. Levator scapulae. 19. 
 Scalenus medius. 20. Trapezius. 
 
 pass upwards and somewhat forwards over the neck, and 
 are lost in the lower part of the face ; some of them decussate 
 at the symphysis of the chin with the corresponding fibres 
 on the opposite side ; others end in the skin, or blend with 
 some of the muscles of the mouth, as described in the dissec- 
 tion of the face. This muscle seems to be, in the human 
 14 
 
158 DISSECTION OF THE NECK. 
 
 body, a vestige of the panniculus carnosus of the lower 
 animals. 
 
 The platysma may now be dissected up from the layer of 
 fascia beneath it, when the following vessels and nerves must 
 be found and studied: 
 
 The EXTERNAL JUGULAR YEIN, Fig. 2, /, and Fig. 62 
 (i, 2, s), formed generally by the union of the temporal and 
 internal maxillary veins, commences close to the angle of 
 the lower jaw, and passes downwards and backwards over 
 the sterno-cleido-mastoideus, towards the centre of the cla- 
 vicle, and terminates usually in the subclavian. It is some- 
 times very small or entirely absent; again, it is very large and 
 sometimes double. It may be large on one side and small on 
 the other. It also varies in its origin and in its termination. 
 As this vein is sometimes opened for the abstraction of blood, 
 it should be particularly noticed. Its direction, in connection 
 with that of the fibres of the platysma, should be observed 
 with reference to the proper mode of opening the vein. It 
 commonly contains two valves one near its' centre and the 
 other near its termination ; the first is sometimes wanting. 
 
 The FACIAL YEIN, Fig. 62 (i e), enters the neck along with 
 the facial artery, and passes down in front of the submaxillary 
 gland, while the artery goes behind it. It most commonly 
 unites with the lingual to form a common trunk which opens 
 into the internal jugular. Its termination, however, is so irre- 
 gular, and of so little consequence, as to deserve no special 
 attention. 
 
 The ANTERIOR JUGULAR, Fig. 2, 7^ commences in the 
 submaxillary region, and, passing down on the anterior part 
 of the neck to the upper border of the sternum, dips beneath 
 the sterno-cleido-mastoideus to reach the subclavian. Some- 
 times, there is no anterior jugular, or it is very small; some- 
 times, it is quite large on one side and very small on the 
 other; again, it may take the place of the external jugular, 
 which will, in that case, be absent. If the student should have 
 an opportunity to dissect the superficial veins of the neck in 
 several subjects, he will observe the great irregularity which 
 exists in their general arrangement. 
 
 The FACIAL ARTERY, Fig. 62 (14), is the only one which 
 deserves any special notice in connection with the superficial 
 
SUPERFICIAL PARTS OF THE NECK. 
 
 159 
 
 fascia. This artery will be seen passing over the base of the 
 inferior maxilla, just in front of the insertion of the masseter, 
 
 Fig. 62. 
 
 A SIDE VIEW OF THE SUPERFICIAL ARTERIES AND VEINS OF THE FACE AND NECK. 
 1. External jugular vein, seen under the platysma rnyoides muscle. 2. Anasto- 
 mosing branch from the cephalic vein of the arm to the external jugular. 3. Ex- 
 ternal jugular after the removal of the platysma muscle. 4. Communication of the 
 external and internal jugulars by means of the facial vein. 5. Occipital vein and 
 branches. 6. Occipital artery. 7. Posterior auricular artery and vein. 8. Point 
 where the external jugular is formed by the union of the temporal and internal 
 maxillary veins. 9. Temporal artery and parietal vein. 10. Frontal branches of 
 the same; on the top of the head are seen the anastomoses of these vessels with the 
 occipital. 11. Internal jugular vein. 12. Superior thyroid artery and vein. 13. 
 Lingual artery and vein. 14. Facial artery. 15. Point of its anastomosis with the 
 nasal branch of the ophthalmic. 16. Facial vein separated from the artery, except 
 at its origin and termination. 17. Inferior coronary artery and vein. 18. Superior 
 coronary artery and vein. 19. Ascending nasal vein. 20. Nasal branches of the 
 ophthalmic artery and vein. 21, 22. Frontal vein. 
 
 or about an inch from the angle of the jaw. The submental 
 branch. Fig. 1 (s), of the facial usually passes up over the 
 lower jaw, near the symphysis of the chin. 
 
160 DISSECTION OF THE NECK. 
 
 The nerves are, the occipitalis minor, the auricularis mag- 
 nus, the superficialis colli, the cervical branches of the facial, 
 and the supra-clavicular "branches. 
 
 The OCCIPITALIS MINOR, Fig. 63 (is), is a small nerve 
 which passes upwards along the posterior border of the 
 sterno-cleido-mastoideus to the occiput. 
 
 The AUKICULARIS MAGNUS, Fig. 63 (12), arises from the 
 second and third cervical nerves, near the middle of the neck, 
 winds obliquely upwards and forwards over the posterior 
 border of the sterno-cleido-mastoideus, and goes up to the 
 
 Fig. 63. 
 
 A VIEW OF THE FACIAL NERVE, TOGETHER WITH THE BRANCHES OF THE CERVICAL 
 PLEXUS, <tc. 1. The portio dura, or facial nerve, escaping from the stylo-mastoid 
 foramen; the parotid gland has been removed, in order to show the nerve more 
 clearly. 2. Its posterior auricular branch. 3. The stylo-hyoid branch. 4. The 
 pes anserinus. 5. Temporal branches of the facial nerve. 6. Malar branches. 7. 
 Cervico-facial branches. 8. Supra-orbital nerve. 9. Subcutaneus malaa, a branch 
 of the superior maxillary nerve. 10. The infra-orbital nerve. 11. Terminal branches 
 of the inferior dental nerve. 12. Nervus auricularis magnus of the cervical plexus. 
 13. The superficialis colli nerve. 14. The plexus formed between the superficialis 
 colli and the branches of the facial. 15. The occipitalis minor, a branch of the cer- 
 vical plexus. 16. Descending branches of the cervical plexus. 17. The phrenic 
 nerve. 18. The spinal accessory of the eighth pair. 19. The great or posterior 
 occipital nerve. 
 
SUPEKFICIAL PARTS OF THE NECK. 161 
 
 parotid region, crossing in its course the sterno-cleido-mas- 
 toideus. It is generally found a short distance behind the 
 external jugular vein, and running nearly parallel to it. Its 
 terminal branches were dissected in connection with the paro- 
 tid and auricular regions. 
 
 The SUPERFICIALIS COLLT, Fig. 63 (i s), arises at the same 
 place as the auricularis magnus, passes over the sterno-cleido- 
 inastoideus, and, going transversely across it and beneath the 
 external jugular vein, divides into ascending and descending 
 branches. The former ascend to the submaxillary region; 
 one or two filaments usually accompany the external jugular 
 vein, and two or three filaments anastomose with the facial 
 beneath the platysma. The latter ramify on the side of the 
 neck, extending to the median line. The superficialis colli 
 sometimes arises, by two trunks, from the cervical plexus. 
 The filaments which accompany the external jugular may be 
 wounded when this vein is opened. 
 
 The CERVICAL BRANCH OF THE FACIAL, Fig. 63 (i 4), leaves 
 the parotid gland near the angle of the lower jaw, beneath 
 which it passes to the anterior and upper part of the neck to 
 near the chin, where it divides into several branches. It 
 runs beneath the platysma, to which it sends filaments. Two 
 or three branches anastomose, as before stated, with the super- 
 ficialis colli, with which they form a plexus. 
 
 The SUPRA-CLAVICULAR AND ACROMIAL NERVES, Fig. 66 
 (IG), arise from the cervical plexus, behind the sterno-cleido- 
 mastoideus, and divide into anterior, middle, and posterior 
 branches. The anterior pass downwards and forwards, over 
 the sterno-cleido-mastoideus, to the anterior and lower part 
 of the neck, and, over the inner part of the clavicle, to the 
 thorax; the middle go directly downwards to the clavicle, 
 which they pass over to reach the thorax ; the posterior or 
 acromial branches pass over the lower portion of the trapezius, 
 and the acromion process and spine of the scapula, to the 
 shoulder. These nerves are distributed to the platysma 
 myoides and to the integument. 
 
 The superficial fascia of the neck may be regarded as con- 
 sisting of the dense areolar tissue which is spread out beneath 
 the skin, being continuous, above, with the superficial fascia 
 of the face, and below with that of the thorax, and containing 
 
162 DISSECTION OF THE NECK. 
 
 the subcutaneous vessels and nerves, the platysma myoides, 
 and lymphatic glands ; while the deep cervical fascia is more 
 dense in its structure, has fixed attachments, and contains 
 between its laminae the deep vessels, nerves, and lymphatic 
 glands, and the muscles. The superficial fascia forms a bond 
 of union between the skin and the deep parts, and retains in 
 situ the subcutaneous vessels, &c. The deep fascia connects 
 together the deep parts, and keeps each one in its proper 
 place. It must be studied as these parts are exposed in the 
 progress of the dissection. 
 
 The superficial fascia may now be raised without preserv- 
 ing the vessels and nerves found in it. This can be done on 
 the opposite side. The following muscles may now be dis- 
 sected : 
 
 The STERNO-CLEIDO-MASTOIDEUS, Fig. 64 (i?), is the 
 largest muscle on the side of the neck. It is separated from 
 the platysma myoides by the deep layer of the superficial 
 fascia, the external jugular vein, the auricularis magnus, 
 the superficialis colli, and the anterior branches of the supra- 
 clavicular nerves, which have already been dissected, and by 
 a thin layer of the deep cervical fascia. This layer of the 
 deep fascia is frequently so thin, that it is difficult to dissect 
 it up as a distinct lamina ; its continuity, however, with the 
 deep fascia, especially at the anterior border of the muscle, 
 will be clearly seen. It arises by two heads ; one from the 
 upper border of the sternum, and the other from the inner 
 extremity of the clavicle. The sternal origin is the narrow- 
 est, and extends tendinous for some distance ; the clavicular 
 origin varies very much in width in different subjects, and 
 its tendinous fibres are shorter. The space between these 
 two heads is occupied by areolar tissue ; it also varies very 
 much in width in different subjects ; sometimes it is scarcely 
 perceptible. The muscle formed by the junction of these 
 two heads passes obliquely upwards and backwards, and is 
 inserted into the mastoid process and the superior semicir- 
 cular ridge of the occipital bone. The action of the two 
 muscles is to approximate the chin to the sternum ; if one 
 acts alone, it will turn the chin to the opposite side. 
 
 This muscle is exposed by making an incision through the 
 fascia, near its anterior border, from its origin to its insertion, 
 and dissecting the fascia off, so as to observe its connection 
 with the deep layer. 
 
SUPERFICIAL PARTS OF THE NECK. 163 
 
 The STERNO-HYOIDEUS, Fig. 64 (i e) and Fig. 69 (i 4), arises 
 from the posterior surface of the sternum, sometimes in part 
 from the sterno-clavicular ligament and the clavicle, or the 
 cartilage of the first rib. It passes upwards, and is inserted 
 into the body of the hyoid bone. It is quite thin, and from 
 half an inch to three-fourths of an inch in breadth. It is 
 separated from its fellow on the opposite side by a thin layer 
 of fascia, especially in front of the trachea and thyroid gland. 
 The proximity of these muscles should be noticed with refer- 
 ence to tracheotomy. 
 
 The OMO-HYOIDEUS, Fig. 64 (ie), is a digastric muscle; 
 its two bellies being connected by a small tendon behind the 
 sterno-cleido-mastoideus. Its posterior belly arises from the 
 upper border of the scapula, near the coracoid notch, and 
 sometimes from the ligament subtending the notch ; its ante- 
 rior belly arises from the body of the hyoid bone. The di- 
 rection of each belly deserves notice. The anterior one, it 
 will be observed, corresponds in its direction very nearly to 
 a line extending from the body of the hyoid bone to the 
 centre of the clavicle. The posterior belly is more transverse 
 in its direction. The tendon, common to these two bellies, is 
 situated in the deep cervical fascia, and so connected with it 
 as to render the fascia tense when the bellies contract. 
 
 Before dissecting the origin of the posterior belly, the an- 
 terior and lower portion of the trapezius may be exposed, 
 and detached from the clavicle and acroraion process. This 
 part of the trapezius, Fig. 64 (22), should be dissected now, so 
 that its relation to the supra-clavicular region may be seen. 
 
 The STERNO-THYROIDEUS, Fig. 69 (is), arises from the 
 posterior surface of the sternum, and sometimes in part from 
 the cartilage of the first or second rib. It passes upwards 
 and is inserted into the oblique ridge on the ala of the thyroid 
 cartilage. It is placed behind the sterno-hyoideus, project- 
 ing some distance beyond its external border. It does not, 
 however, like that muscle, approximate closely to its fellow 
 on the opposite side, and hence it is not directly concerned 
 in the anatomy of tracheotomy. It is considerably broader 
 than the sterno-hyoideus. 
 
 The THYRO-HYOIDEUS, Fig. 64 (i 5), is a short muscle which 
 arises from the thyroid cartilage, and passes over the thyro- 
 hyoid space, and is inserted into the hyoid bone. It appears 
 
164 
 
 DISSECTION OF THE NECK. 
 
 to be a continuation of the sterno-thyroideus, and unless the 
 student is on his guard, it will be dissected up with that 
 muscle. 
 
 Fig. 64. 
 
 A LATERAL VIEW OP THE DEEP-SEATED LAYER OP MUSCLES ON THE FACE AND 
 NECK. 1. Temporal muscle deprived of its fascia. 2. Corrugator Supercilii. 3. 
 Pyramidalis nasi. 4. Superior or nasal extremity of the levator labii superioris alse- 
 que nasi. 5. Compressor naris. 6. Levator anguli oris. 7. Depressor labii superioris 
 alaeque nasi. 8. Buccinator. 9. Orbicularis oris. 10. Depressor labii inferioris. 11* 
 Levator labii inferioris. 12. Anterior belly of the digastricus. 13. Mylo-hyoid. 
 14. Stylo-hyoid. 15. Thyro-hyoid. 16. Upper belly of the Omo-hyoid. 17. 
 Sterno-cleido-mastoid. 18. Sterno-hyoid. 19. Scalenus anticus. 20. Pectoralis 
 major. 21. Deltoid. 22. Trapezius. 23. Scalenus Medius. 24. Levator sca- 
 pulae and scalenus posticus. 25. Splenius. 26. Complexus. 
 
 If the dissector should find it necessary to detach either 
 of these muscles at one of their extremities, in order to ex- 
 pose another, it should be done so that the muscle can be 
 replaced again in its natural position. The sterno-cleido- 
 mastoideus can be detached at its origin, and raised up for 
 
SUPEKFICIAL PAKTS OF THE NECK. 165 
 
 some distance, without injuring anything of importance. 
 The sterno-hyoideus may also be detached at its origin and 
 turned upwards, so as to dissect the muscle beneath it. 
 
 The actions of the three last muscles will be readily un- 
 derstood by observing their attachments. 
 
 The sterno-, thyro-, and omo-hyoid muscles, Fig. 67 (e), re- 
 ceive nervous filaments from the descendens noni ; the thyro- 
 hyoid is supplied by a filament from the hypoglossal. These 
 nerves may be looked for while dissecting the muscles, or 
 their examination may be postponed until the opposite side 
 is dissected. The same course may be pursued with regard 
 to the arteries going to them. 
 
 The DIGASTKICUS, Fig. 69 (i, 2), arises from the digastric 
 fossa and mastoid process, and from the base of the inferior 
 maxilla close to the symphysis ; the two bellies are inserted 
 into an intermediate tendon, which is connected by tendinous 
 fibres to the hyoid bone. The posterior belly is the longest 
 and more transverse in its direction. The tendon of this 
 muscle perforates the anterior extremity of the stylo-hyoideus. 
 A little care is necessary, or this arrangement may be de- 
 stroyed before it is observed. The deep fascia of the neck 
 is connected to the digastric muscle, which deserves to be 
 noticed. The origin of the posterior belly of this muscle 
 need not be exposed at present, as it is covered by the sterno- 
 cleido-mastoideus. The action of this muscle is to depress 
 the lower jaw, or, when this is fixed, to elevate the hyoid 
 bone. 
 
 If the student has been successful thus far in his dissection 
 of the neck, he will encounter but little difficulty in com- 
 pleting it in a manner satisfactory to himself. All the more 
 prominent points are now distinctly brought into view, and 
 their relations to the other parts are such that he will be able 
 to locate and find them without much trouble. He can now 
 readily trace upon the subject the boundaries of the follow- 
 ing subdivisions or surgical regions. 
 
 Each side of the neck is divided into five regions ; the 
 submaxillary, the superior carotid, the inferior carotid, the 
 supra- clavicular, and a fifth one, which is situated behind the 
 sterno-cleido-mastoideus, and above the posterior belly of the 
 omo-hyoideus muscle. 
 
 The SUBMAXILLARY KEGION is bounded above by the in- 
 
166 DISSECTION OF THE NECK. 
 
 ferior maxilla, below and in front by the anterior belly of 
 the digastricus, below and behind by the posterior belly of 
 the same muscle, and by a process of the deep fascia, which 
 is attached to the stylo-maxillary ligament, and separates this 
 region from the parotid. 
 
 The SUPERIOR CAROTID EEGION is bounded above by the 
 posterior belly of the digastricus, behind by the sterno-cleido- 
 mastoideus, below and in front by the anterior belly of the 
 omo-hyoideus. 
 
 The INFERIOR CAROTID EEGION is bounded anteriorly by 
 the median line, above by the anterior belly of the omo- 
 hyoideus, and behind and below by the sterno-cleido-mas- 
 toideus. 
 
 THE SUPRA-CLAVICULAR EEGION is bounded in front by 
 the sterno-cleido-mastoideus, above by the posterior belly of 
 the omo-hyoideus, and below by the clavicle. 
 
 The FIFTH EEGION, or SUB-OCCIPITAL, is bounded in front 
 by the sterno-cleido-mastoideus, below by the omo-hyoideus, 
 and behind by the trapezius. 
 
 A sixth region, embracing the parts concerned in the opera- 
 tions of laryngotomy and tracheotomy, or laryngo-tracheo- 
 tomy, may be conveniently made by the student. It is not 
 necessary, however, to give any specific boundaries to such 
 a region. 
 
 The lower part of the neck, embracing the inferior carotid 
 and supra-clavicular regions, and extending upwards to the 
 bifurcation of the common carotid artery, is to be dissected 
 next. 
 
 If the sterno-cleido-mastoideus, sterno-hyoideus, and sterno- 
 thyroideus have not been detached at their origins, it should. 
 be done now. The overlapping of the sternal origin of the 
 sterno-cleido-mastoideus should be noticed, with reference to 
 ligation of the common carotid artery. Beneath the sterno- 
 hyoid and thyroid are the trachea and thyroid gland. A 
 plexus of veins, Fig. 66, coming from the thyroid gland, is 
 usually situated directly in front of the trachea, and is liable 
 to be wounded in tracheotomy. 
 
 The middle thyroid artery, sometimes called the artery of 
 JSTeubauer, when present, is found in this region. It is not 
 very often met with, and is so irregular in its origin and 
 
SUPERFICIAL PAETS OF THE NECK. 167 
 
 course, that no rule can be laid down for avoiding it in 
 opening the windpipe. There are no nerves in front of the 
 trachea which deserve any special notice. It is separated 
 from the muscles by a layer of the deep fascia, by areolar 
 tissue, and by the thyroid gland. 
 
 The THYROID GLAND consists of two lobes, connected 
 across the upper rings of the trachea, usually the second and 
 third. It is of a reddish color and exceedingly vascular. 
 The lobes are situated more on the sides than in front of the 
 trachea. They are somewhat conical in shape; the small 
 end being above. Each one extends from about the sixth 
 ring up to the thyroid cartilage, and projects backwards 
 between the sheath of the common carotid and the wind- 
 pipe. The portion connecting the two lobes is called the 
 isthmus. This varies much in size, a point which deserves 
 special notice in reference to tracheotomy. A small body 
 projects upwards from the isthmus, or from one of the lobes 
 called the pyramid, and this again is connected to the hyoid 
 bone by a fibrous structure, which, from its resemblance to 
 muscle in some cases, has been called the levator glandulce, 
 thyroidecB. 
 
 There is perhaps no organ in the body which presents so 
 great a variety in its development as the thyroid gland. It 
 is not necessary to specify these variations, as the student 
 will be able to note them as he happens to meet with them 
 in his dissections. Whatever may be the office of the 
 thyroid gland, whether of great or little importance in the 
 economy, it is liable to abnormal or pathological changes, 
 which are of the utmost consequence to the physician. 
 
 It has no excretory duct, and, consequently, cannot be 
 classified with the true glands which elaborate and secrete a 
 known fluid. Its arteries are derived from the subclavian 
 and external carotid. At this stage of the dissection, the 
 student will observe merely the terminal branches of the 
 thyroid arteries. Those of the inferior thyroid will be seen 
 entering for the most part the under surface of the lower 
 portion of the gland, while those of the superior penetrate 
 the anterior surface of the upper part. This mode of en- 
 tering the gland seems to result from, or at least to corre- 
 spond to, the superficial and deep situation of the superior 
 and inferior thyroid arteries. 
 
168 DISSECTION OF THE NECK. 
 
 The veins go to form the tracheal plexus, which has been 
 alluded to in connection with the anterior relations of the 
 trachea. 
 
 The anterior part of the larynx may now be noticed, espe- 
 cially the crico -thyroid space, as connected with the opera- 
 tion of laryngotomy. A small artery crosses this space 
 transversely, resting upon the anterior crico-thyroid liga- 
 ment, and sending a branch through it to the mucous mem- 
 brane. The anterior portion of the cricoid and thyroid 
 cartilages should also be inspected in situ. 
 
 When the parts in front of the trachea and larynx have 
 been duly examined, the dissection is to be continued in a 
 lateral direction. As the two sides of the neck differ in this 
 region in some material points, the right side will be examined 
 first, and the peculiarities of the left will be noticed in an- 
 other place. 
 
 The first thing to be sought in this region is the ARTERIA 
 INNOMINATA, Fig. 66 (i o). This will be found immediately 
 beneath the sterno-clavicular articulation, covered by fascia. 
 Only the upper portion of it will be seen in the dissection of 
 the neck. When its bifurcation into the common carotid and 
 the subclavian is found, the sheath of the former may be laid 
 open to near its division into the external and internal caro- 
 tids. Before doing this, however, the relation of the omo- 
 hyoideus to the artery should be observed ; also, the course 
 of the descendens noni nerve, which lies upon the sheath com- 
 mon to the artery and internal jugular vein. Some small 
 nervous filaments will be noticed crossing the artery, and 
 which are liable to be divided in ligating it. Having exposed 
 the common carotid, the following parts will be found with- 
 out difficulty : 
 
 On the outside, and running parallel to it, is the INTERNAL 
 JUGULAR. As this vein is traced downwards, it will be seen 
 that it does not terminate at the commencement -of the carotid, 
 Fig. 66 (i e), but passes over the subclavian artery to join the 
 subclavian vein, and with it form the vena innominata. By 
 separating the carotid from the jugular vein, the pneumo- 
 gastric nerve will be brought into view. It lies behind and 
 between these great vessels, and in the same sheath. It may 
 be traced downwards over the subclavian artery, where it 
 gives off the inferior laryngeal branch, which winds round the 
 
SUPEEFICIAL PAETS OF THE NECK. 
 
 169 
 
 posterior surface of the subclavian artery to ascend to the 
 larynx. 
 
 Fig. 65. 
 
 30 29 
 
 A VIEW OF THE ARTERIES OF THE NECK AND SHOULDER.!. Primitive carotid 
 artery. 2. Internal carotid artery. 3. External carotid artery. 4. The superior 
 thyroid artery. 5. Branches to the muscles. 6. Main branch to the gland. 7. In- 
 ferior pharyngeal artery. 8. Lingual artery. 9. Facial artery. 10. Its branches 
 to the submaxillary gland. 11. Subtnental branch. 12. Principal branch of the 
 facial as it goes over the jaw. 13. Occipital artery. 14. Branches to the muscles 
 on the back of the neck. 15. Main trunk to the occiput. 16. Posterior auricular 
 artery. 17. A branch cut off, which goes to the parotid gland. 18. Origin of the 
 internal maxillary artery. 19. Origin of the temporal artery. 20. Origin of the 
 anterior auricular. 21. The subclavian. 22. Origin of the internal mammary. 
 23. Trunk of the inferior thyroid, from which arise in this subject the anterior and 
 posterior cervical arteries. 24. Branch of the inferior thyroid going to the thyroid 
 gland. 25. Ascendens colli going up the neck. 26. Posterior or transverse cervical. 
 27. Branches to the scaleni and levator scapulae muscles. 28. The supra-scapular 
 artery. 29. The thoracica acromialis of the axillary artery. 30. A branch to the 
 deltoid. 31. Recurrent branches of the intercostals. 
 
 This branch of the pneumogaetric may be traced from its 
 origin to its entrance into the larynx. Leaving the artery 
 and proceeding a short distance obliquely inwards and up- 
 15 
 
170 DISSECTION OF THE NECK. 
 
 wards, it gets into the groove formed by the trachea and 
 ossophagus, and continues in this groove to the lower border 
 of the inferior constrictor muscle of the pharynx, to which it 
 gives some filaments ; it then passes round outside the crico- 
 thyroid articulation, to divide into branches to supply all 
 the muscles of the larynx except the crico- thyroid. While 
 in connection with the subclavian artery, it gives off branches 
 to join the cardiac branches of the sympathetic. It also, in 
 its course, sends filaments to the trachea, oesophagus, and 
 thyroid gland. The situation of this nerve is to be noticed as 
 connected with oesophagotomy. 
 
 About an inch and a half from the bifurcation of the 
 arteria innominata, the inferior thyroid artery passes trans- 
 versely beneath the common carotid, the internal jugular, 
 and the pneumogastric nerve. The course of this artery 
 should be observed as connected with the ligation of the 
 carotid, and also with oesophagotomy. 
 
 The dissection is now to be extended along the course of 
 the SUBCLAVIAN AETEEY, Fig 65 (21). This artery, from 
 its relations to the scalenus anticus muscle, is divided into 
 three sections : the first extends from its commencement to 
 the inner border of the scalenus; the second includes that 
 portion directly behind the muscle, and the third division ex- 
 tends from the outer border of this muscle to the point where 
 it passes over the first rib to terminate in the axillary artery. 
 
 The deep cervical fascia in this region is quite thick and 
 dense. It is firmly attached to the clavicle and first rib. 
 The vessels and nerves, and the scalenus anticus, obtain 
 investments from it. A prolongation is also sent down from 
 it into the thorax, along with the trachea and the large vessels 
 and nerves which enter that cavity from the neck. The dis- 
 section of this region is somewhat difficult. The parts will be 
 noticed in the order in which they seem most naturally to 
 present themselves to the dissector. The internal jugular 
 vein and the pneumogastric nerve may be divided some 
 distance above the subclavian artery, and reflected down- 
 wards. Filaments of the sympathetic may be noticed passing 
 over the artery to enter the thorax. 
 
 The BRANCHES of the subclavian artery are numerous, 
 and, with the exception of one, have their origin on the inner 
 side of the scalenus. The thyroid axis, as it is called, is some- 
 times the common origin of the inferior thyroid, the supra- 
 
SUPERFICIAL PARTS OF THE NECK. 
 
 171 
 
 scapular, and the transverse humeral. As these branches, 
 so frequently arise separately, although near to each other, 
 the term " thyroid axis" might very properly be abandoned. 
 
 Fig. 66. 
 
 A VIEW OF THE HEART, WITH THE GREAT VESSELS OP THE NECK IN SITU. 1. 
 Right ventricle of the heart. 2. Right auricle. 3. Left ventricle. 4. Left auricle. 
 5. Pulmonary artery. 6. Arch of the aorta. 7. Descending vena cava at its 
 entrance into the right auricle. 8. Ascending vena cava. 9. Thoracic aorta. 10. 
 Arteria innominata. 11. Right brachio-cephalic vein. 12. Left brachio-cephalic 
 vein. 13. Section of the subclavian artery. 14. Section of the subclavian vein. 
 15, 15. Primitive carotid arteries. 16, 16. Internal jugular veins. 17, 17. External 
 jugular veins. Between these veins is seen the section of the sterno-cleido-mastoid 
 muscle. 18. The trunk formed by the superficial cervical veins, known sometimes 
 as the anterior jugular vein. 19. A branch from it to the facial. 20. Main trunk 
 from the inferior thyroid veins. 21. Superior thyroid vein. 22. Transverse cer- 
 vical artery and vein. 23. Lingual artery and vein. 24. Facial artery and vein. 
 
 The INFERIOR THYROID, Fig. 65 (2 3), comes off from the 
 anterior and upper aspect of the artery, a short distance 
 from the scalenus; it passes upwards about an inch, when it 
 
172 DISSECTION OF THE NECK. 
 
 turns inwards and dips beneath the jugular vein, common 
 carotid artery, and pneumogastric nerve, to go to the thyroid 
 gland, to which the greater part of it is distributed. It sends 
 small branches to the oesophagus, the trachea, and to the 
 larynx. The middle cervical ganglion of the sympathetic, 
 when it exists, rests upon it. 
 
 The ASCENDENS COLLI, Fig. 65 (2 5), is usually a branch 
 of the thyroid ; the point of its origin, however, varies ; some- 
 times it comes off as the thyroid turns inwards, and if it be 
 large, causes the appearance of a bifurcation of that artery. 
 It ascends upon the scalenus anticus on the neck, giving 
 branches to this muscle and to the rectus capitis anticus major, 
 and the levator anguli scapulae. It also gives off branches to 
 anastomose with the vertebral artery, and to enter the spinal 
 canal along with the cervical nerves. 
 
 The SUPRA-SCAPULAR ARTERY, Fig. 65 (as), passes trans- 
 versely outwards, just behind the clavicle, to reach the cora- 
 coid notch ; it does not usually pass through the notch, but 
 immediately over the ligament which converts it into a fora- 
 men. It is situated beneath the deep fascia, and in its course 
 gives off a small branch which enters the thorax. On the 
 dorsum of the scapula it anastomoses beneath the acromion 
 with the arteria dorsalis scapulae. 
 
 The TRANSVERSE HUMERAL, or CERVICAL, Fig. 65 (as), 
 passes transversely outwards, but above the preceding, to the 
 trapezius. It is distributed to the muscles on the back of 
 the neck, and anastomoses with the arteria princeps cervicis, 
 a branch of the occipital artery. Both of the last named 
 arteries are to be studied in their relations to the operation 
 for ligating the subclavian artery. 
 
 The INTERNAL MAMMARY ARTERY, Fig. 65 (22), arises 
 from the lower surface of the subclavian, and very soon 
 enters the thorax. It passes beneath the clavicle, the sub- 
 clavian vein, and the phrenic nerve, before it gets behind the 
 first rib. Its course in the thorax, and in the anterior walls 
 of the abdomen, will be noticed in the dissection of those 
 parts. It may be mentioned now that it anastomoses with 
 several arteries, as the superior thoracic, the intercostal, 
 and the epigastric. These anastomotic connections render 
 its study important. 
 
SUPERFICIAL PARTS OF THE NECK. 173 
 
 Fig. 67. 
 
 THE COURSE AND DISTRIBUTION OP THE HYPOGLOSSAL OR NINTH PAIR OF NERVES. 
 
 THE DEEP-SEATED NERVES OF THE NECK ARE ALSO SEEN. 1. The hypoglossal 
 
 nerve. 2. Branches communicating with the gustatory nerve. 3. A branch to tho 
 origin of the hyoid muscles. 4. The descendens noni nerve. 5. The loop formed 
 with the branch from the cervical nerves. 6, 6. Muscular branches to the depressor 
 muscles of the larynx. 7. A filament from the second cervical nerve, and 8. A 
 filament from the third cervical, uniting to form the communicating branch with 
 <he loop from the descendens noni. 9. The auricular nerve. 10. The inferior 
 dental nerve. 11. Its mylo-hyoidean branch. 12. The gustatory nerve. 13. The 
 chorda tympani passing to the gustatory nerve. 14. The chorda tympani leaving 
 the gustatory nerve to join the submaxillary ganglion. 15. The submaxillary 
 ganglion. 16. Filaments of communication with the lingual nerve. 17. The 
 glosso-pharyngeal nerve. 18. The par vagum or pneumogastric nerve. 19. The 
 three upper cervical nerves. 20. The four inferior cervical nerves. 21. The first 
 dorsal nerve. 22, 23. The brachial plexus. 24, 25. The phrenic nerve. 26. Tho 
 carotid artery. 27. The internal jugular vein. 
 
 The VERTEBRAL ARTERY, Fig. 68 (7), is the largest branch 
 of the subclavian. It arises from the upper and posterior 
 part of that artery, and passes directly up to the foramen 
 in the transverse process of the sixth cervical vertebra, 
 which it traverses, and also the corresponding foramina of the 
 upper five vertebras ; it enters the cranial cavity through the 
 foramen occipitale, to be distributed to the brain and its me- 
 ninges. In its course along the neck it sends branches tp 
 the spinal canal, and gives off also some small muscular 
 twigs. It varies in its origin in different subjects, and on 
 
 15* 
 
174: 
 
 DISSECTION OF THE NECK. 
 
 Fig. 68. 
 
 A VIEW OF THE VERTEBRAL ARTERY, 
 CAROTID AND ARCH OP THE AORTA, AS GIVEN 
 BY A VERTICAL SECTION OF THE NECK. 1. 
 Commencement of the thoracic aorta. 2. plies the Upper tWO inter- 
 
 rPV^ ivms^OTt !wr 4-n r*t ^4- rx*inivt Q TVrt l/\Pf i JT 
 
 the two sides in the same 
 subject; also in the num- 
 ber of transverse processes 
 through which it passes. 
 
 From the posterior part 
 of the subclavian two 
 branches arise, sometimes 
 separately and sometimes 
 by a common trunk the 
 superior intercostal and 
 the profound cervical. 
 
 The SUPERIOR INTER- 
 COSTAL passes over the 
 neck of the first rib and 
 enters the superior inter- 
 costal space ; on the right 
 side, it very frequently sup- 
 
 The innominata at its origin. 3. The left , - 
 
 subclavian. 4. The internal mammary COStai Spaces. 
 
 artery. 5. The artery of the right side. 
 
 6. The inferior thyroid. 7. The vertebral 
 
 in the transverse processes of the cervical 
 
 vertebrae. 8. Superior intercostal artery, 
 
 9. Left primitive carotid. 10. External 
 
 carotid artery. 11. Superior thyroid. 12. 
 
 The lingual, which has here a common 
 
 trunk with the facial. 13. Internal carotid. 
 
 14. Origin of the aorta. 
 
 The PROFOUND CERVI- 
 CAL passes backwards be- 
 tween the transverse pro- 
 cess of the seventh cervical 
 vertebra and the first rib. 
 It assists in supplying the 
 deep muscles on the back. 
 
 The small veins in this region correspond to the branches of 
 
 the subclavian artery. 
 
 The PHRENIC NERVE, Fig. 67 (24), arises from the third 
 and fourth cervical, and passes obliquely downwards and in- 
 wards over the scalenus anticus to enter the thorax. The 
 subclavian vein lies in front of it, and the internal mammary 
 artery behind it. It communicates usually by one or two 
 filaments with the descendens noni ; it is also generally con- 
 nected by a branch of considerable size with the fifth cervical 
 nerve. As it crosses the scalenus it is bound down by fascia. 
 
 The SUBCLAVIAN VEIN, Fig. 66 (14), extends from the 
 sterno-clavicular articulation to the first rib, on the inner side 
 of the scalenus anticus, which separates it from the subclavian 
 artery. It is more superficial than the artery, and on a plane 
 
SUPERFICIAL PARTS OF THE NECK. 175 
 
 lower down. It receives the external jugular, which, usually 
 enters it a little on the outside of the scalenus, or in front of 
 it. The external jugular occasionally terminates in the inter- 
 nal jugular. The veins corresponding to the supra-scapular 
 and transverse humeral arteries enter the subclavian. 
 
 The SCALENUS ANTICUS MUSCLE, Fig. 71 (2), arises from 
 the transverse processes of the third, fourth, fifth, and sixth 
 cervical vertebrae, and is inserted in a tubercle on the first rib. 
 It draws the first rib up, or turns the head to one side. 
 This muscle and the tubercle which indicates the point of its 
 insertion furnish important guides for finding the subclavian 
 artery, and, on this account, they demand the special atten- 
 tion of the student. This muscle may now be detached from 
 the rib and turned upwards, when the middle division of the 
 subclavian artery is brought into view. It is in relation with 
 the pleura, first rib, the lower cervical and first dorsal nerves, 
 and the anterior and middle scaleni muscles. 
 
 The POSTERIOR CERVICAL ARTERY usually arises from the 
 outer portion of this division. This artery passes transversely 
 outwards to be distributed to the muscles on the back ; some- 
 times it is a branch of the transverse humeral. It is liable 
 to be injured in ligating the subclavian artery between the 
 scalenus anticus and the first rib. 
 
 Outside the scalenus anticus is the SUPRA-SCAPULAR 
 NERVE, which arises from the fifth cervical and passes down- 
 wards and backwards, beneath the trapezius and omo-hy- 
 oideus, to reach the coracoid notch of the scapula. It enters 
 the supra-spinata fossa, and is distributed to the parts on the 
 dorsum of the scapula. 
 
 The third division of the subclavian artery and the nerves 
 which form the brachial plexus are in this region. The 
 artery passes over the first rib to terminate in the axillary. 
 The nerves lie partly behind and above it, but in close rela- 
 tion to it. The scalenus medius is sometimes perforated by 
 one or more of them. The superior and long thoracic 
 branches generally have their origin from these nerves above 
 the clavicle. 
 
 The SCALENUS, MEDIUS and POSTICUS, may be considered 
 as a single muscle which arises from the transverse processes 
 of the inferior six cervical vertebra, and is inserted into the 
 first and second ribs. 
 
176 DISSECTION OF THE NECK. 
 
 The upper part of the superior carotid and the submaxil- 
 lary regions will be described separately, as far as the student 
 will be able to dissect conveniently the parts which they 
 contain, without destroying or displacing too much their 
 boundaries. Some parts will be partly brought into view 
 and noticed without their being fully dissected and exposed 
 until a more advanced stage of the dissection ; and some 
 which are deep-seated can be dissected better without refer- 
 ence to regions, as the deep muscles, the sympathetic, and 
 the nerves generally in the upper and deep part of the neck, 
 consequently these will be described under the head of the 
 deep parts of the neck. 
 
 The submaxillary region contains the SUBMAXILLARY 
 GLAND, Fig. 3 (3), which should be dissected first, on account 
 of its size and the important relations which it sustains to 
 the vessels and nerves of that region. This gland is covered 
 by a layer of the deep fascia in which it is embedded. It is 
 of an irregular shape ; the transverse diameter being somewhat 
 greater than the vertical. In structure, it resembles the other 
 salivary glands. Anteriorly, it projects over the mylo- 
 hyoideus, and sends a prolongation beneath it ; below, it is 
 in relation with the digastric and stylo-hyoid muscles ; pos- 
 teriorly, it rests against the process of the deep fascia which 
 is attached to the stylo-hyoid ligament ; above, it occupies a 
 fossa on the inner surface of the lower jaw. There are seve- 
 ral lymphatic glands situated in this region around the sub- 
 maxillary gland. They receive lymphatics from the mouth, 
 face, and pharynx ; hence they are liable to become affected 
 in cases of disease located in either of these regions. An 
 enlarged lymphatic gland, in the immediate vicinity of the 
 submaxillary, might be mistaken for disease of the submax- 
 illary gland itself. 
 
 In dissecting this gland, the following parts will be brought 
 into view : 
 
 The FACIAL ARTERY, Fig. 65 (9), passes beneath its posterior 
 extremity, occupying a sulcus in its substance, and sending 
 branches to it. The submental branch (i i) of the same artery 
 gives small branches to the gland, and passes forwards over 
 the mylo-hyoideus to near the symphysis of the chin, where, 
 after giving branches to the parts beneath the chin, it goes 
 up over the jaw to the face. The facial artery usually gives 
 
SUPERFICIAL PARTS OF THE NECK. 177 
 
 off two or three other small branches in this region, one to 
 the pterygoideus internus, and another to the soft palate. 
 
 The HYPOGLOSSAL NERVE, Fig. 67 (i), enters the anterior 
 and lower part of the submaxillary region from beneath the 
 digastricus and stylo-hyoideus ; runs a short distance before 
 it gets on the anterior surface of the hyo-glossus, just above 
 the greater cornu of the hyoid bone ; it then passes upwards 
 and forwards between the hyo-glossus and mylo-hyoideus to 
 reach the tongue. In its course through this region it gives 
 off branches to the thyro-hyoideus, stylo-glossus, and hyo- 
 glossus, and to anastomose with the gustatory branch of the 
 fifth nerve. 
 
 The GUSTATORY or LINGUAL BRANCH, Fig. 67 (12), of the 
 fifth enters this region at the anterior border of the ptery- 
 goideus intern us, and partly behind the gland. This nerve 
 is brought into view by separating the gland from the lower 
 jaw, and loosening it up from the hyo-glossus. It passes 
 over the hyo-glossus and along the stylo-glossus muscle, in 
 nearly a transverse direction, to the genio-hyo-giossus, which 
 it perforates, to go to the sublingual gland and mucous mem- 
 brane of the mouth. With a very little care in exposing this 
 nerve, the submaxillary ganglion may be observed connected 
 to its lower border, and situated nearly opposite the centre 
 of the submaxillary gland. From this ganglion filaments 
 are sent to the substance of the gland, and to the duct of 
 Wharton, and mucous membrane of the mouth. The gan- 
 glion is quite small, of a grayish color, and often appears 
 like a slight projection from the nerve. It is classed with 
 the cranial ganglia of the sympathetic. The vidian nerve is 
 said to terminate in it after accompanying for some distance 
 the gustatory. 
 
 The MYLO-HYOID branch of the inferior dental nerve enters 
 this region above the gland, and close to the inner surface of 
 the jaw, and gets on the cutaneous surface of the mylo-hyoi- 
 deus, to which, and the digastricus, it sends filaments, and 
 also to the gland. 
 
 The anterior belly of the digastricus may now be detached 
 from the lower jaw, and reflected downwards without destroy- 
 ing its attachment to the hyoid bone. The insertion of the 
 stylo-hyoideus may also be observed at the same time. Re- 
 moving the areolar tissue, mylo-hyoid nerve, submental 
 
178 
 
 DISSECTION OF THE NECK. 
 
 artery and vein, and the anterior projection of the gland, 
 from the cutaneous surface of the mylo-hyoideus, the origin 
 and insertion of this muscle will be exposed. 
 
 The MYLO-HYOIDEUS, Fig. 69 (5), is a broad muscle, and 
 from its important relations deserves special notice. It arises 
 
 Fig. 69. 
 
 THE MUSCLES OF THE ANTERIOR ASPECT OP THE NECK ; ON THE LEFT SIDE THE 
 SUPERFICIAL MUSCLES ARE SEEN, AND ON THE RIGHT THE DEEP. 1. The posterior 
 belly of the digastricus muscle. 2. Its anterior belly. The aponeurotic pulley, 
 through which its tendon is seen passing, is attached to the body of the os hyoides. 
 3, 4. The stylo-hyoideus muscle, transfixed by the posterior belly of the digastricus. 
 5. The mylo-hyoideus. 6. The genio-hyoideus. 7. The tongue. 8. The hyo- 
 glossus. 9. The stylo-glossus. 10. The stylo-pharyngeus. 11. The sterno-mastoid 
 muscle. 12. Its sternal origin. 13. Its clavicular origin. 14. The sterno-hyoid. 
 15. The sterno-thyroid of the right side. 16. The thyro-hyoid. 17. The hyoid 
 portion of the omo-hyoid. 18, 18. Scapular portions j on the left side, the tendon 
 of the muscle is seen to be bound down by a portion of the deep cervical fascia. 
 19. The clavicular portion of the trapezius. 20. The scalenus anticus of the right 
 side. 21. The scalenus posticus. 
 
 from the mylo-hyoid ridge, on the inner surface of the 
 lower jaw ; its fibres pass downwards, forwards, and inwards, 
 to be inserted into the hyoid bone, and to join its fellow on 
 the opposite side along the median line. This muscle may 
 draw up the hyoid bone, or, when it is fixed, may depress 
 the lower jaw. A small triangular space, occupied by areo- 
 lar tissue, exists between the two mylo-hyoid muscles just 
 
SUPEEFICIAL PAETS OF THE^ NECK. 179 
 
 below the symphysis of the chin. This muscle should be 
 carefully detached from the mylo-hyoid ridge, and from the 
 hyoid bone, and reflected to the opposite side, when the 
 liypoglossal and gustatory nerves, and the duct of Wharton will 
 be seen resting on the hyo-glossus. The duct, for a short 
 distance after leaving the gland, is situated between these 
 nerves, but nearer to the gustatory than the hypoglossal, 
 which crosses it. 
 
 The DUCT OF WHARTON is nearly two inches in length ; 
 its walls are very thin in proportion to its caliber. It leaves 
 the hyo-glossus, and gets at first between the genio-hyo- 
 glossus and the sublingual gland, then between the gland and 
 the mucous membrane, between which it continues to the frse- 
 num of the tongue, just behind the incisor teeth. The student 
 will have no difficulty in tracing this duct, if an incision be 
 made into it near its origin, and a bristle introduced and 
 carried through it into the mouth. Its proximity to the 
 cavity of the mouth, in the latter part of its course, and the 
 distensible character of its parietes, deserve notice, with refe- 
 rence to ranula, or an enlargement of the duct from closure 
 of its buccal orifice. 
 
 The GENIO-HYOIDEUS, Fig. 69 (e), is a small muscle which 
 arises from the lower jaw, near the symphysis, and passes 
 downwards and backwards, and is inserted into the hyoid bone. 
 The two genio-hyoidei muscles are frequently so closely con- 
 nected along the median line that it is not easy to separate 
 them. The action of this muscle is nearly the same as that 
 of the preceding one. After detaching this muscle from its 
 origin, and reflecting it downwards, the anterior border of 
 the genio-hyo-glossus will be seen. The genio-hyoid part of 
 it may now be observed, but its connection with the tongue 
 must be examined when that organ is dissected. The sub- 
 maxillary gland may next be removed entirely, when the 
 hyo-glossus, the stylo-glossus, the stylo-pharyngeus, the lin- 
 gual artery, and the sublingual gland, with a portion of the 
 mucous membrane of the mouth, will be brought into view. 
 
 The STYLO-GLOSSUS, Fig. 70 (3), arises 'from the styloid 
 process and stylo-maxillary ligament, passes downwards and 
 forwards to be lost principally in the side of the tongue. 
 As it enters this organ its fibres spread out, and a few of 
 
180 DISSECTION" OF THE NECK. 
 
 them pass transversely across it, It acts on the sides and 
 tip of the tongue. 
 
 Fig. 70. 
 
 THE ANATOMY OP THE SIDE OP THE NECK, SHOWING THE NERVES OP THE TONGUE. 
 1. A fragment of the temporal bone containing the meatus auditorius externus, 
 inastoid, and styloid processes. 2. The stylo-hyoid muscle. 3. The stylo-glossus. 4. 
 The stylo-pharyngeus. 5. The tongue. 6. The hyo-glossus muscle ; its two por- 
 tions. * 7. The genio-byo-glossus muscle. 8. The genio-hyoideus ; they both arise 
 from the inner surface of the symphysis of the lower jaw. 9. The sterno-hyoid 
 muscle. 10. The sterno-thyroid. 11. The thyro-hyoid, upon which the thyro- 
 hyoidean branch of the hypoglossal nerve is seen ramifying. 12. The omo-hyoid 
 crossing the common carotid artery (13), and internal jugular vein (14). 15. The 
 external carotid giving off its branches. 16. The internal carotid. 17. The gusta- 
 tory nerve giving off a branch to the submaxillary ganglion (18), and communi- 
 cating a little further on with the hypoglossal nerve. 19. The submaxillary, or 
 Wharton's duct, passing forwards to the sublingual gland. 20. The glosso-pharyn- 
 geal nerve, passing in behind the hyo-glossus muscle. 21. The hypoglossal nerve 
 curving around the occipital artery. 22. The descendens noni nerve, forming a 
 loop with (23) the communicans noni, which is seen to be arising by filaments from 
 the upper cervical nerves. 24. The pneumogastric nerve, emerging from between 
 the internal jugular vein and common carotid artery, and entering the chest. 25. 
 The facial nerve, emerging from the stylo-mastoid foramen, and crossing the exter- 
 nal carotid artery. 
 
 The HYO-GLOSSUS, Fig. 70 (e), is a thin square muscle, 
 which arises from the body and great cornu of the hyoid 
 bone; its fibres pass upwards and are inserted into the tongue, 
 
SUPERFICIAL PARTS OF THE NECK. 181 
 
 between the stylo-glossus, with which its fibres intermix, and 
 the lingualis. 
 
 The LINGUAL ARTERY, Fig. 65 (s), enters the submaxillary 
 region a short distance outside the free extremity of the great 
 cornu of the hyoid bone, and on a plane somewhat deeper. 
 It almost immediately passes behind the hyo-glossus muscle, 
 just above the cornu of the hyoid bone, to get between 
 the genio-hyo-glossus and lingualis. The middle constrictor 
 of the pharynx lies behind it, in the first part of its course. 
 The situation and relations of this artery should be noticed 
 with reference to the application of a ligature to it. 
 
 The STYLO -PHARYNGEUS MUSCLE, Fig. 70 (4), arises from 
 the styloid process, passes downwards and inwards to the 
 pharynx, which it enters between the superior and middle 
 constrictors. The glosso-pharyngeal nerve runs along the 
 side of this muscle between it and the stylo-glossus to the 
 margin of the hyo-glossus, beneath which it passes to the 
 base of the tongue, sending filaments in this region to the 
 pharyngeal plexus. The dissector will find the stylo-pharyn- 
 geus muscle a guide for finding this nerve. 
 
 The SUBLINGUAL GLAND, Fig. 3 (s), is the smallest of the 
 three large salivary glands. It is situated near the symphy- 
 sis of the chin, occupying a fossa on the inner side of the 
 lower jaw. Its upper surface is covered by the mucous 
 membrane of the mouth, between the incisor teeth and the 
 tongue ; below, it rests upon the mylo-hyoideus muscle ; ante- 
 riorly, it is in relation with the lower jaw. It is sometimes 
 connected by a process with the submaxillary gland. Its 
 excretory ducts are ten or twelve in number. They open into 
 the mouth near the frsenum of the tongue. Sometimes they 
 are called the ducts of Rivinus. A communication occasion- 
 ally exists between these ducts and the duct of Wharton. 
 
 The relations of the submaxillary and sublingual glands 
 are worthy of particular notice. It will be observed that the 
 submaxillary is covered externally by skin, superficial fascia, 
 platysma myoides, and deep fascia, while the sublingual is 
 covered internally by mucous membrane r and submucous 
 areolar tissue. The mylo-hyoideus forms the principal sep- 
 tum between them. They are both in apposition with the 
 lower jaw; the sublingual occupying the sublingual fossa, 
 16 
 
182 DISSECTION OF THE NECK. 
 
 and the submaxillary the submaxillary fossa, while the two 
 fossae are separated by the mylo-hyoid ridge. 
 
 In dissecting the upper part of the superior carotid region, 
 the first thing which should be sought is the hypoglossal 
 nerve. This enters it beneath the posterior belly of the di- 
 gastricus, at a point almost directly below the angle of the 
 lower jaw, passes downwards, forwards, and upwards, to enter 
 the submaxillary region near the free end of the great cornu 
 of the hyoid bone. It thus forms a curve in this region, the 
 convexity of which looks downwards. The lowest part of 
 this curve is about three-fourths of an inch below the digas- 
 tricus. As it descends beneath the digastricus, it gives off 
 the descendens noni. 
 
 The DESCENDERS NONI, Fig. 67, (4, 5), passes vertically 
 downwards, receiving one or two branches from the second 
 cervical nerve, or cervical plexus, by which a loop is formed ; 
 from the convexity of this loop, filaments are sent to the omo- 
 hyoideus and sterno-hyoideus and thyroideus. The apparent 
 origin of this varies in different subjects. Sometimes it seems 
 to come from the pneumogastric, occupying, in this case, for 
 a short distance, the groove behind and between the common 
 carotid and internal jugular vein; again, it will be found 
 leaving the hypoglossal high up in the parotid region. 
 
 If there be any difficulty in finding the nerve in the upper 
 part of this region, it is better either to find one of its branches 
 and trace it upwards, or to trace the hypoglossal nerve itself 
 up into the parotid region. In this way the student will be 
 certain to find it. The descendens noni usually, near its com- 
 mencement, winds round the occipital artery. As this nerve 
 lies on the sheath of the common carotid, it is liable to be 
 injured in ligating that artery. 
 
 The SPINAL ACCESSORY NERVE passes through the upper 
 and posterior part of this region, to perforate the sterno-cleido- 
 mastoideus. It is is most readily found by carefully dissect- 
 ing the inner and posterior surface of that muscle, and look- 
 ing for the nerve as it enters it. Occasionally, the nerve 
 passes beneath the muscle. 
 
 The superior laryngeal branch of the pneumogastric may be 
 found with the laryngeal branch of the superior thyroid ar- 
 tery, between the hyoid bone and the thyroid cartilage. "They 
 pass beneath the thyro-hyoid muscle, to perforate the thyro- 
 
SUPERFICIAL PARTS OF THE NECK. 183 
 
 hyoid membrane. This nerve can be exposed more con- 
 veniently at another stage of the dissection of the neck. 
 Having found this portion of it, the student may avoid 
 destroying it as he proceeds. 
 
 As the lower part of the inferior carotid region has already 
 been dissected, the student will have no difficulty in tracing 
 the arteries in its upper part. The common carotid usually 
 bifurcates at a point nearly opposite to the superior border 
 of the thyroid cartilage. The external is at first more internal 
 than the internal carotid itself. It gives off the following 
 branches before passing beneath the digastricus: 
 
 The SUPERIOR THYROID, Fig. 65 (4), arises near the bifur- 
 cation, passes inwards, forwards, and downwards, beneath the 
 omo-hyoideus and sterno-thyroideus, to be distributed to the 
 upper and anterior portion of the thyroid gland. It usually 
 gives off the laryngeal branch, which goes to the thyro-hyoid 
 space to enter the larynx ; the cricoid branch, which rests on 
 the anterior crico-thyroid ligament; a branch to the sterno- 
 cleido-mastoideus ; and branches to the muscles with which 
 it is connected. This artery is quite superficial in its course. 
 
 The lingual arises just above the preceding, and passes up- 
 wards and inwards to enter the submaxillary region. It is 
 deep-seated in its whole course. 
 
 The facial artery comes off just below the digastric muscle, 
 and goes up into the submaxillary region. 
 
 The inferior or ascending pharyngeal arises near the bifur- 
 cation and from the deep part of the artery, and goes upwards 
 to the jugular foramen, through which it enters the cavity of 
 the cranium, sending branches, as it ascends, to the pharynx 
 and soft palate. 
 
 The OCCIPITAL, Fig. 65 (i 3), arises from the posterior part 
 of the artery, passes upwards and backwards, at first behind 
 the digastricus, and then more horizontally beneath the sterno- 
 cleido-mastoideus, trachelo-rnastoideus, and splenius capitis, to 
 reach the occiput. It emerges beneath the integument and 
 fascia, just outside the cranial origin of the trapezius. It 
 gives off branches to the muscles along its course, and, just 
 before it ascends on the occiput, it sends downwards quite a 
 large branch, called the arteria princeps cervicis; this branch 
 descends on the back of the neck, and anastomoses with the 
 transverse humeral. The occipital artery ramifies on the 
 back of the head, beneath the skin. 
 
184: DISSECTION OF THE NECK. 
 
 The POSTERIOR AURICULAR, Fig. 65 (i 6), arises above, or 
 in common with, the occipital, and passes upwards and back- 
 wards between the mastoid process and meatus auditorius. 
 It ramifies on the external ear, and beneath the integument 
 behind the ear. 
 
 The styloid is more frequently a branch of the posterior 
 auricular ; it enters the foramen stylo-mastoideum, and goes 
 to the middle ear. 
 
 Besides the branches just mentioned, the external carotid 
 generally sends two or three small ones to the sterno-cleido- 
 mastoideus. 
 
 SECT. II. DISSECTION OF THE DEEP PARTS OF THE NECK. 
 
 The examination of these parts requires a displacement of 
 the lower jaw, or at least the half on the side upon which 
 they are to be dissected. The only additional section which 
 will be required will be through the symphysis of the chin, 
 when the remaining portions of the jaw upon that side may 
 be drawn upwards and forwards, out of the way, or they 
 may be entirely removed. 
 
 The parts to be examined in the present dissection are the 
 internal carotid artery, the internal jugular vein, the pneumo- 
 gastric, the glosso-pharyngeal, the spinal accessory, the hypo- 
 glossal, and the sympathetic nerves, and the pharyngeal plexus, 
 and some of the deep muscles of the neck. Most of the parts 
 just enumerated have been examined as they were found in 
 the different regions already dissected. The following de- 
 scription, therefore, will be confined principally to those por- 
 tions of them which remain to be exposed. 
 
 The branches of the external carotid may be cut away, as 
 the dissector shall find it necessary, in the progress of the 
 dissection. The digastricus and the stylo-hyoideus may be 
 divided near their hyoid attachments, and reflected backwards. 
 
 The INTERNAL CAROTID, Fig. 65 (2), passes upwards nearly 
 in a vertical direction from the bifurcation 01 the common 
 carotid, to the foramen caroticum in the petrous portion of 
 the temporal bone, through which it enters the cranial cavity. 
 In the superior carotid region, it is quite superficial, being 
 covered merely by the integument, platysma myoides, and 
 
DEEP PAKTS OF THE NECK. 185 
 
 the superficial and deep fascise; but, as it ascends, it gradu- 
 ally becomes deeper seated. Its size is not varied in this 
 part of its course. 
 
 Below the digastricus, the hypoglossal nerve and the occip- 
 ital artery cross it in front, while the external carotid lies 
 on the inner side of it. Above the digastricus, and in the 
 parotid region, it is crossed in front by the glosso-pharyngeal 
 nerve and the stylo-glossus and stylo-pharyngeus muscles, 
 Fig. 67, which pass between it and the external carotid. It 
 is also covered by the parotid gland, in which it is sometimes 
 partially lodged. 
 
 On its inner side are the pharynx and sympathetic nerve. 
 Externally it is in relation with the internal jugular, the 
 pneumogastric, the , hypoglossal, and glosso-pharyngeal 
 nerves. These nerves at first lie behind it, but soon get on 
 the outside between it and the vein. The two latter, how- 
 ever, do not continue in this connection down to the common 
 carotid, but cross over in front of the artery, the one above, 
 and the other below the digastricus, as before mentioned. 
 
 Behind, it rests on the rectus capitis anticus major, separ- 
 ated from it by fascia and by the pharyngeal and superior 
 laryngeal branches of the pneumogastric, which pass inwards 
 beneath it. 
 
 The inferior or ascending pharyngeal artery runs at first 
 on the inner side of the internal carotid, then behind it, up 
 to the foramen lacerum poster ius, or jugular foramen. The 
 internal carotid is surrounded by a plexus of nerves. 
 
 The relation of this artery to the pharynx is worthy of 
 notice. It sustains nearly the same relation to the internal 
 surface of the pharynx, as regards the intermediate structures, 
 that it does to the external surface of the neck in the supe- 
 rior carotid region. 
 
 The INTERNAL JUGULAR YEIN, Fig. 67 (2 7), commences at 
 the foramen lacerum posterius, and terminates by uniting 
 with the subclavian to form the vena innominata. Near the 
 foramen it js removed a short distance from the internal 
 carotid, the intermediate space being occupied by nerves. 
 There is also a small space between it and the common 
 carotid in the lower part of the neck. This vein is a con- 
 tinuation of the lateral sinus ; it increases in size as it re- 
 ceives collateral branches in its course down the neck. It 
 
186 DISSECTION OF THE NECK. 
 
 presents two enlargements, one near its commencement, and 
 the other just above its termination. It has no valves. 
 
 The GLOSSO-PHARYNGEAL NERVE, Fig. 67 (17), is a part 
 of the eighth. It passes through the foramen lacerum pos- 
 terius in a fibrous canal by itself. It descends, at first be- 
 tween the internal jugular and internal carotid, then in front 
 of the artery and behind the styloid process and its muscles ; 
 it now turns inwards, and passing in front of the stylo-pha- 
 ryngeus, gets between it and the stylo-glossus ; continuing 
 this course, it passes beneath the hyo-glossus, and enters the 
 base of the tongue, to terminate in the papillae of the mucous 
 membrane. 
 
 There are two ganglia or gangliform swellings on this 
 nerve; a small one in the foramen lacerum, and a larger 
 one, the petrous or ganglion of Andersch, a little lower down. 
 From the ganglion of Andersch proceed branches to anasto- 
 mose with the sympathetic, the facial, the pneumogastric, 
 and the nerves in the middle ear. The glosso-pharyngeal 
 receives filaments from the spinal accessory, by which it be- 
 comes partly a motor nerve in its distribution. Its muscu- 
 lar branches are sent to the stylo-pharyngeus, stylo-hyoideus ? 
 digastricus, hyo-glossus, and superior and middle constrictor 
 muscles. The last-named muscles obtain their filaments 
 through the medium of the pharyngeal plexus. Its sym- 
 pathetic filaments go to the carotid plexus, and thus connect 
 with the superior cervical ganglion. The tympanic branch, 
 or Jacobson's, enters a small foramen between the jugular 
 foramen and foramen caroticum to go to the tympanum. This 
 branch is noticed more particularly in connection with the 
 ear. Its anastomotic branch to the facial winds round the 
 styloid process, and joins that nerve just as it emerges from 
 the stylo-mastoid foramen. It also sends filaments to the 
 tonsils and palatine arches, forming the tonsillitic plexus. 
 
 The HYPO GLOSSAL, or the NINTH NERVE, supplies the 
 muscles of the tongue and larynx with voluntary motor fila- 
 ments. It enters the neck through the anterior condyloid 
 foramen ; just below which it is connected by filaments with 
 the loop formed by the first and second cervical nerves, 
 with the sympathetic by a small filament which comes from 
 the superior cervical ganglion, and also with the pneumo- 
 
DEEP PARTS OF THE NECK. 187 
 
 gastric. It anastomoses with the gustatory branch of the 
 fifth in the submaxillary region, just before it passes beneath 
 the mylo-hyoideus. The course of this nerve in the carotid 
 and submaxillary regions, with the descendens noni and its 
 other branches given off in these regions, has been described. 
 In the parotid region it lies at first between the internal 
 carotid and internal jugular, and behind the pneumogastric. 
 As it descends, it gets on the outside of the pneumogastric, 
 then in front of it, to turn inwards across the neck, and to- 
 wards the tongue. 
 
 The SPINAL ACCESSOEY leaves the cranial cavity with the 
 glosso-pharyngeal and pneumogastric, passing through the 
 foramen lacerum posterius with the latter. Just below the 
 foramen it sends a large branch to join the pneumogastric, 
 thus supplying this nerve with involuntary motor filaments. 
 It also communicates with the sympathetic and ninth nerves. 
 The main trunk descends, usually behind the jugular vein 
 and the styloid muscles, to perforate the sterno-cleido-mas- 
 toideus, or to send a branch to it, and then to pass on to the 
 trapezius. Behind the sterno-cleido-mastoid it anastomoses 
 with the cervical plexus. 
 
 The PNEUMOGASTKIC, or PAE VAGUM, is the largest divi- 
 sion of the eighth nerve. It passes through the foramen 
 lacerum posterius in the same fibrous canal with the spinal 
 accessory. There is a small ganglion situated on it in the 
 foramen, and below the foramen it presents a gangliform 
 arrangement of about an inch in length. It here lies be- 
 tween the carotid and the jugular vein. It gives off several 
 communicating branches. From the superior ganglion fila- 
 ments connect with the glosso-pharyngeal and spinal acces- 
 sory; while from the inferior ganglion filaments communicate 
 with the hypoglossal, the upper spinal, and the sympathetic 
 nerves. 
 
 The auricular branch of the pneumogastric leaves the su- 
 perior ganglion, and after giving a small branch to Jacob- 
 son's branch of the glosso-pharyngeal, enters the petrous 
 portion of the temporal bone in the jugular fossa, and joins 
 the facial nerve in its bony canal, sending filaments also to 
 the integument around the meatus externus. 
 
 The pliaryngeal branch arises just below the foramen, 
 sometimes receiving a branch from the spinal accessory, and 
 
188 DISSECTION OF THE NECK. 
 
 occasionally from the glosso-pharyngeal, and passes beneath 
 the internal carotid to join, on the side of the pharynx, fila- 
 ments from the glosso-pharyngeal, superior laryngeal, and 
 superior cervical ganglion, to form the pharyngeal plexus. 
 
 The superior laryngeal has its origin generally from the 
 inferior ganglion near its middle. It is considerably larger 
 than the preceding branch. It passes downwards and in- 
 wards beneath the internal carotid, giving off in its course 
 filaments to the superior cervical ganglion, to the hypo- 
 glossal and pharyngeal plexus. It divides into an external 
 and internal branch. The former is the smallest ; it is dis- 
 tributed to the external muscles of the larynx, to the thy- 
 roid gland, and anastomoses with the recurrent laryngeal, 
 and cardiac branches of the sympathetic. The internal 
 branch passes beneath the thyro-hyoid muscle, and per- 
 forates the thyro-hyoid membrane, to be distributed to the 
 mucous membrane of the larynx. This is the sensor nerve 
 of the larynx. 
 
 The course of the pneumogastric nerve through the carotid 
 regions and the recurrent branch, have already been de- 
 scribed. Just before it enters the thorax it sends off branches 
 to the heart ; they unite with branches of the sympathetic, 
 to form the anterior cardiac plexus. 
 
 The SYMPATHETIC KEKVE traverses the neck from the 
 base of the cranium to the thorax. It presents three cervi- 
 cal ganglia, a superior, middle, and inferior. The number, 
 however, is subject to variation ; there being sometimes but 
 two, and again there may be four. When three are present, 
 the superior is situated in front of the second cervical ver- 
 tebra ; the middle opposite to the fifth, and the inferior corre- 
 sponds to the seventh vertebra. 
 
 The superior ganglion is usually about an inch in length ; 
 its lower extremity is commonly larger than the upper, some- 
 times it is bifid, and it may taper as it descends in the neck, 
 below the second vertebra, which sometimes occurs. This 
 ganglion connects above by filaments which ascend into the 
 carotid canal, with the carotid plexus, and through this plexus 
 with several of the cranial ganglia. Externally, it communi- 
 cates with the four superior cervical nerves, by filaments which 
 can be traced into the inter- vertebral foramina. Internally, 
 it is connected by branches with the pharyngeal and laryn- 
 
DEEP PARTS OF THE NECK. 189 
 
 geal branches of the pneumogastric and the pharyngeal 
 branches of the glosso -pharyngeal. The pharyngeal branches 
 contribute to form the plexus which supplies the pharynx 
 and fauces ; the laryngeal join the superior laryngeal nerve. 
 Anteriorly, it gives oft' branches to join the eighth and ninth 
 nerves, and to go to the external carotid, from which fila- 
 ments proceed to accompany its different branches. These 
 filaments have been called, from their soft texture, " nervi 
 molles" 
 
 The superior cardiac nerve arises from the inner side of the 
 ganglion, by one or more filaments, descends behind the 
 carotid and alongside of the trachea, and, passing in front of 
 the inferior thyroid artery, enters the thorax in company 
 with the arteria innominata. In its course down the neck it 
 communicates with the pneumogastric and its laryngeal 
 branches, also with the middle and inferior ganglia. 
 
 The middle ganglion sends branches to one or two of the 
 cervical nerves, and to the pneumogastric. The middle cardiac 
 nerve arises from this ganglion when it is present. It pur- 
 sues a course similar to the superior cardiac nerve. It com- 
 municates with the recurrent laryngeal and superior cardiac. 
 
 The inferior ganglion is dissected more satisfactorily in con- 
 nection with the thoracic division of the sympathetic. The 
 student must be prepared to meet with numerous variations 
 in the arrangement of the sympathetic nerve. It is impos- 
 sible to give a description of it which will correspond exactly 
 with any two dissections. But a general knowledge of the 
 numerous connections of this nerve is essential to a correct 
 idea of its functions, and the influence it may exert in various 
 pathological conditions of the body. 
 
 The muscles which may now be examined, are the follow- 
 ing: 
 
 The KECTUS ANTICUS MAJOR, Fig. 71 (i), arises from the 
 transverse processes of the third, fourth, fifth, and sixth 
 cervical vertebras, passes upwards and is inserted into the 
 cuneiform process of the occipital bone in front of the fora- 
 men magnum. It presents a tendinous intersection, which 
 gives attachment to many of its muscular fibres. 
 
 KECTUS ANTICUS MINOR, Fig. 71 (4), arises from the trans- 
 verse process of the atlas, and is inserted into the cuneiform 
 
190 
 
 DISSECTION OF THE NECK. 
 
 Fig. 71. 
 
 process of the occipital bone. It covers, in front, the articu- 
 lation between the atlas and occiput. 
 
 The KECTUS CAPITIS LATE- 
 KALIS, Fig. 71 (i o), arises from 
 the transverse process of the 
 atlas, and is inserted into the 
 jugular eminence, on the occi- 
 pital bone. It separates the 
 jugular vein in front from the 
 vertebral artery behind. The 
 action of the recti muscles is to 
 support the head, or to bend it 
 slightly forwards or laterally. 
 
 The LONGUS COLLI, Fig. 71 
 (5,5), consists of three portions. 
 The first arises from the central 
 and anterior tubercle of the 
 atlas, and passes down to be in- 
 serted into the transverse pro- 
 cesses of the third, fourth, and 
 fifth cervical vertebrae. The 
 second arises from the transverse 
 processes of the third and fourth 
 i. The rectus an ti- cervical vertebrae, and goes 
 
 cus major muscle. 2. The scalenus anti- J nwn fo ~u p n it nr hpf] f o fhp 
 
 cus. 3. The lower part of the longus colli ( LO ^ n tO De 
 
 of the right side; it is concealed superi- bodies of the upper three ClOr- 
 
 sal vertebra3. The third arises 
 from the second and third cer- 
 
 THE PRJEVERTEBRAL GROUP OF Mus 
 
 CLES OF THE NECK. 
 
 orly by the rectus anticus major. 4. The 
 rectus anticus minor. 5. The upper 
 portion of the longus colli muscle. 
 
 its lower portion; the figure rests upon ^Q^ vertebrae, and passes down 
 
 the seventh cervical vertebra. 7. The , . , . ' , i -i j - ff 
 
 scalenus medius. 8. Scalenus posticus. to be inserted into the bodies ol 
 
 9. One of the intertransversales mus- -fche lower four Cervical and 
 
 llft'side!' Th6 reCtUS lateraUS f the u Pl?er three dorsal vertebras. 
 
 This muscle supports the ver- 
 tebral column. 
 
 From the experience acquired in the dissection of one side, 
 the student will be able to go over the same ground ^ the 
 second time with more satisfaction to himself. If some things 
 have escaped his attention, or he has failed to obtain a dis- 
 tinct and correct view of them in his first dissection, he will 
 have the opportunity of remedying these defects in his second. 
 And he cannot acquire too great familiarity with any of the 
 
DEEP PAETS OF THE NECK. 191 
 
 parts, even if he should find it convenient to examine them 
 repeatedly. His attention in the second dissection of the 
 same parts should be directed more particularly to relational 
 anatomy. The following are some of the points especially 
 deserving of his notice: The operations of laryngotomy, 
 tracheotomy, pharyngotomy, and oesophagotomy ; the parts 
 to be cut through, and those to be avoided in these opera- 
 tions ; also the parts which are liable to be divided in attempts 
 to commit suicide by cutting the throat. 
 
 The young physician is liable to be called upon to treat 
 these wounds without being allowed time to consult his 
 books, and consequently he should make himself thoroughly 
 acquainted, when he has the opportunity, with the exact loca- 
 tion and the relations of all the parts liable to be implicated 
 in such injuries. The application of ligatures to the various 
 arteries of the neck, and the anastomotic connections between 
 them ; also the manner in which the circulation will be carried 
 on when any particular artery is obliterated. The formation 
 of tumors, and the effect they will be likely to have on the 
 surrounding parts, whether those parts be vessels and nerves 
 or the windpipe, the oesophagus, &c. 
 
 In dissecting the left side, some peculiarities will be met 
 with which do not occur on the right side. These are located 
 in the lower part of the neck. They are introduced sepa- 
 rately instead of alluding to them in connection with the de- 
 scription of the right side, as it was thought this method 
 would be less likely to cause embarrassment, especially to 
 the beginner. 
 
 The LEFT or GKEAT THOKACIC DUCT enters the neck be- 
 hind and internal to the subclavian artery, opposite to the 
 sixth or seventh cervical vertebra ; gets behind the internal 
 jugular, and curves outwards, forwards, and downwards to 
 open into the junction of the internal jugular and subclavian 
 veins. If it be not injected, the student may have some 
 difficulty in distinguishing it from the surrounding tissues. 
 It is easily found, however, in the abdomen ; and, by insert- 
 ing a blowpipe into it there, it may be filled with air, when 
 it will swell up and be readily observed in the neck. It 
 varies in its mode of termination ; sometimes it opens by two 
 trunks, one into the jugular and the other into the subcla- 
 vian ; or it may open singly into either one of these veins. 
 
192 DISSECTION OF THE NECK. 
 
 It may divide into two trunks in the thorax, and while one 
 opens in the usual place on the left side, the other may open 
 into the right subclavian along with the common lymphatic 
 duct of the right side. 
 
 The SUBCLAVIAN ARTERY on the left side arises from the 
 aorta, and consequently is longer than the one on the right 
 side. The second and third divisions have the same relations 
 as on the right side, but with the first or inner section it is 
 quite different. Its direction is nearly vertical, and it 
 makes, in passing" behind the scalenus anticus, a much shorter 
 turn. It is covered anteriorly by the same parts, although 
 it is deeper seated. The pneumogastric does not pass over 
 it, nor does the inferior laryngeal or recurrent nerve wind 
 around its posterior surface. It is also in relation with the 
 thoracic duct. 
 
 The COMMON CAROTID arises from the aorta, and therefore 
 is longer than the right. It is nearer to the internal jugular 
 and the oesophagus, and is also in relation to the thoracic 
 duct. Its connections in the thorax will be mentioned when 
 that cavity is examined. 
 
 The INTERNAL JUGULAR VEIN on the left side requires no 
 special notice. The pneumogastric nerve does not, as before 
 mentioned, pass in front of the subclavian artery as on the 
 right side ; nor does it give off the recurrent branch until it 
 has reached the arch of the aorta. 
 
 The oesophagus projects a little more on the left side than 
 on the right, and hence it is advised that when it is necessary 
 to open it that it should be done on this side. 
 
 SECT. III. DISSECTION OF THE LARYNX. 
 
 The larynx is situated in the upper and anterior part of 
 the neck, in front of the pharynx and above the trachea. It 
 presents a regular framework, which is composed of several 
 nbro-cartilages joined together by ligaments. It is supplied 
 with muscles, vessels, nerves, and mucous membrane. Its 
 structure is such that it remains constantly patulous, while 
 the mobility of its cartilages adapts it to the production of 
 the voice. For the purposes of respiration merely, a very 
 
OF THE LARYNX. 193 
 
 V 
 
 simple arrangement would have been sufficient, as in the 
 case of the trachea and bronchial tubes. To make a thorough 
 examination of this organ, the student should be provided 
 with at least two larynges ; one for the dissection of the 
 cartilages and ligaments, and another for the muscles, ves- 
 sels, and nerves. 
 
 The HYOID BONE should be examined before the dissec- 
 tion of the cartilages and ligaments of the larynx. It is 
 situated between the base of the tongue and the upper part 
 of the larynx, and is connected to both of these organs. It 
 is named from its having a form resembling the Greek letter 
 upsilon. Its position is nearly horizontal, being concave pos- 
 teriorly and convex anteriorly. 
 
 It consists of a central part or body, and four lateral por- 
 tions called cornua. There are two cornua on each side, one 
 large and one small. 
 
 The Body, Fig. 72 (i ), is curved and flattened. It presents a 
 superior anterior, and inferior posterior surface. The ante- 
 rior superior surface is rough and 
 uneven for the attachment of mus- Fi &- 72 - 
 
 cles. The inferior posterior surface 
 is excavated, and sometimes occu- 
 pied by a yellow areolar tissue. Its 
 upper border gives attachment to 
 the hyo-glossal membrane or sep- 
 tum of the tongue. The thyro- 
 hyoid muscle is inserted into its ANANTERIORVlEWOPTHEOs 
 
 inferior border. HYOIDES. 1. The anterior con- 
 
 The Great Cornua, Fig, 72 (A x side of the body. 2. The 
 
 v ,' 7 cornu majus of the left side. 3. 
 
 proceed backwards from the ends The cornu minus of the same 
 of the body, and, diminishing in side - The cornua were ossified 
 size, terminate in tubercles. In the SStoSf 1 f the bone in this 
 young bone, they are connected to 
 
 the body by cartilage. They present a superior and an in- 
 ferior surface. 
 
 The Small Cornua, Fig. 72 (3), are two small bodies 
 which project upwards from the junction of the body with 
 the great cornua. The stylo-hyoid ligaments are inserted 
 into them. These ligaments are sometimes found ossified. 
 
 The principal cartilages are the cricoid, the thyroid, the 
 
194 
 
 DISSECTION OF THE NECK. 
 
 Fig. 73. 
 
 two arytenoid, and the epiglottis. Besides these, there are 
 four small bodies, two of which are named the appendices, 
 and two the cuneiform bodies. 
 
 The CRICOID CARTILAGE, Fig. 73, is situated in the lower 
 part of the larynx, and seems to belong partly to the larynx 
 and partly to the trachea. It con- 
 sists of a ring slightly elliptical, its 
 transverse diameter being less than 
 its antero-posterior. Its lower bor- 
 der is horizontal, and corresponds to 
 the first ring of the trachea. Its 
 upper border is oblique from before 
 backwards and upwards, making its 
 vertical diameter about four times 
 greater behind than before. It has 
 four articular facets, two for the 
 thyroid cartilage and one for each of 
 the arytenoid. The former are situ- 
 ated on its external surface, behind 
 the centre and near the lower mar- 
 gin. The latter are on its upper 
 border behind, and about one-fourth 
 of an inch apart; they are convex 
 and sloping laterally, being adapted 
 to the articular facets on the bases 
 of the arytenoid cartilages. Its ante- 
 
 ro-lateral surface is convex, and is principally occupied by 
 the crico-thyroid muscle. On its posterior surface are ob- 
 served two depressions, which give attachment to the crico- 
 arytenoidei postici muscles. These .depressions are separated 
 by a vertical ridge, to which are attached some of the longi- 
 tudinal muscular fibres of the oesophagus. Its internal sur- 
 face is smooth and covered by mucous membrane. 
 
 The THYROID CARTILAGE, Fig. 74, forms the upper, ante- 
 rior, and lateral parts of the larynx. It consists of two plates 
 or alse, which are joined at the median line in front, and 
 separated behind nearly three-fourths of an inch. The angle 
 formed by the junction of the alae anteriorly is more promi- 
 nent above than below, and more in the male than in the 
 female. It forms what is called the "pomum Adami." On the 
 external surface of each ala are two tubercles connected by 
 
 A FRONT VIEW OP THE CRI- 
 COID CARTILAGE. 1. Its in- 
 ternal face. 2. The cavity of 
 the larynx as formed by this 
 cartilage. 3. Its inferior sur- 
 face. 4, 4. The little heads 
 or convexities for articulating 
 with the arytenoids. 5, 5. The 
 surface of the superior edge for 
 the attachment of the lateral 
 crico-arytenoid muscles. 
 
OF THE LARYNX. 
 
 195 
 
 Fig. 74. 
 
 an oblique ridge. The lower tubercle is situated anteriorly 
 and near the inferior border, while the upper one is placed 
 posteriorly and near the su- 
 perior border. The surface 
 above and anterior to the 
 oblique ridge is much larger 
 than the one below and be- 
 hind it. The latter is occu- 
 pied by the sterno-thyroid, 
 and the former by the thyro- 
 hyoid muscle. The inferior 
 border of each ala terminates 
 behind in a projection down- 
 wards, called the inferior or 
 small cornu. It articulates 
 with the cricoid cartilage. 
 Just before the small cornu 
 on each side is quite a deep 
 notch; there is also another 
 one, but not so deep in front. 
 The upper border of each ala 
 terminates posteriorly in a 
 much longer projection, call- 
 ed the superior or great cor- 
 nu ; this is inclined backwards, and gives attachment to the 
 lateral thyro-hyoid ligament. Anteriorly there is quite a 
 deep notch, which can be distinctly felt in the living body. 
 The posterior borders of the alas are thick and round for 
 the attachment of the fibres of the inferior constrictor of 
 the pharynx. 
 
 The ARYTENOID CARTILAGES, Figs. 75, 76, are situated 
 behind, upon the cricoid, and between the ala3 of the thyroid. 
 They are of a pyramidal form. The posterior surface of each 
 is concave, and occupied by the arytenoid muscle. The ante- 
 rior surface is convex, with a slight elevation near the apex 
 for the attachment of the superior vocal chord. The internal 
 surface is flat and smooth. The base projects anteriorly 
 nearly one-third of the way across the interior of the larynx, 
 and gives insertion to the inferior vocal chord. It also pro- 
 jects posteriorly and externally for the attachment of the 
 crico-arytenoideus posticus muscle. The articular surface on 
 
 A LATERAL VIEW OP THE THYROID 
 CARTILAGE. 1. Its left half. 2. Its right 
 half. 3. The superior margin. 4. The 
 notch. 5. Anterior angle. 6. Inferior 
 margin. 7. Posterior margin. 8, 8. Cor- 
 nu majus of each side. 9. Cornu minus. 
 
196 
 
 DISSECTION OF THE NECK. 
 
 the base is concave, and adapted to the corresponding articu- 
 lar surface on the cricoid cartilage. The arytenoid cartilages 
 belong essentially to the vocal chords, and as such should be 
 
 Fig. 75. 
 
 AN ANTERIOR VIEW OP THE LEFT 
 ARYTENOID CARTILAGE. 1. Its ante- 
 rior face. The other references as in 
 Fig. 76. 
 
 A POSTERIOR VIEW OP THE LEFT 
 ARYTENOID CARTILAGE. 1. Its poste- 
 rior face. 2. The summit. 3. The 
 base and cavity for articulating with 
 the cricoid cartilage. 4. Its external 
 angle. 5. Its internal angle. 
 
 studied. They can be moved in an outward, inward, back- 
 ward, and forward direction, and also allow to some extent 
 of a spiral movement. By means of these 
 Fig. 77. movements the vocal chords can be made 
 
 tense or relaxed, and the size of the fissure 
 between them, called the rima glottidis, can 
 be increased or diminished in width. 
 
 The APPENDICES are two small bodies 
 surmounting the apices of the arytenoid 
 cartilages. They are inclined backwards 
 and towards each other, lengthening the 
 curvature of these cartilages in this direc- 
 tion, and at the same time increasing their 
 vertical diameter. 
 
 The EPIGLOTTIS, Fig. 77, is generally 
 spoken of as a fibro-cartilage, although its 
 structure seems to be peculiar to itself. It 
 is of an oval form. Its posterior surface is 
 concave transversely, and convex vertically ; 
 its anterior surface is just the reverse. The 
 upper part of its anterior surface is free, 
 and covered by mucous membrane, while 
 the lower part is attached to the tongue, os 
 hyoides, and thyroid cartilage. It is con- 
 
 A LATERAL VIEW 
 OF THE EPIGLOTTIS. 
 1. Anterior or convex 
 surface. 2. Posterior 
 or concave surface. 
 
 3. Superior margin. 
 
 4. Inferior margin or 
 pedicle. 5, 5. Its 
 sides. The openings 
 of the muciparous 
 ducts are also shown. 
 
OF THE LARYNX. 197 
 
 nected to the tongue by yellow elastic tissue, to the body of 
 the os hyoides by ligamentous fibres, and also to the thyroid 
 cartilage just above the anterior insertion of the vocal chords. 
 Between the two latter attachments is found a mass of cellulo- 
 adipose tissue, of a yellowish color, and surrounded by 
 areolar tissue ; it has been called the "epiglottic gland," but 
 without any good reason, as it is destitute of all the elements 
 of a true gland. On the posterior surface of the epiglottis 
 are observed numerous small foramina, orifices of mucous 
 follicles. It is of a yellowish color, and very flexible and 
 elastic, being easily depressed so as to meet the glottis in the 
 ascent of the larynx, by the passage of food from the fauces 
 into the pharynx, immediately recovering its vertical posi- 
 tion when the pressure is removed. It is never found ossi- 
 fied, like the other cartilages of the larynx. 
 
 The cuneiform bodies are two small masses, found in the 
 aryteno-epiglottidean folds of the mucous membrane, a short 
 distance above the appendices orcornicula. Sometimes they 
 are very indistinct, and possess very little firmness. 
 
 The ligaments connecting the cartilages of the larynx to 
 each other, and to the hyoid bone, are the following : 
 
 The thyroid cartilage is connected to the os hyoides by a 
 middle and two lateral ligaments. 
 
 The MIDDLE THYRO-HYOID, Fig. 79 (4), is a broad, yellow 
 ligament, extending from the centre of the upper border of 
 the thyroid to the posterior part of the body of the os hy- 
 oides. The LATERAL, Fig. 78 (4, 4), are round, fibrous cords, 
 connecting the superior cornua of the thyroid to the extre- 
 mities of the great cornua of the os hyoides. The spaces 
 between these ligaments are occupied by dense areolar tissue. 
 The ligamentous attachments of the epiglottis have been 
 spoken of in connection with that body. 
 
 The cricoid cartilage is joined to the thyroid by three liga- 
 ments, two lateral, and one middle. 
 
 The LATERAL LIGAMENTS, Fig. 78 (9, 9), are regular capsular 
 ligaments, containing, in each, a synovial sac. These articu- 
 lations allow of a gliding and rotary movement. The MIDDLE 
 CRICO-THYROID, Fig. 79 (i o), is of the yellow elastic tissue, 
 connecting the anterior part of the upper border of the cri- 
 coid with the corresponding portion of the lower margin of 
 the thyroid. It is perforated by one or more foramina, for 
 
 17* 
 
198 
 
 DISSECTION OF THE NECK. 
 
 the transmission of vessels. It serves to keep the thyroid in 
 its proper position, without interfering with its necessary 
 
 Fig. 78. 
 
 Fig. 79. 
 
 A POSTERIOR VIEW OP THE ARTICU- 
 LATIONS OP THE CARTILAGES OF THE LA- 
 RYNX. 1. Posterior face of the epiglot- 
 tis. 2, 2. Appendices of the os byoides. 
 3, 3. Its cornua. 4, 4. Lateral thyro-hyoid 
 ligaments. 5. Posterior face of the thy- 
 roid cartilage. 6, 6. Arytenoid cartilages. 
 7. Cricoid cartilage. 8, 8. Crico-arytenoid 
 articulations. 9,9. Lateral crico-thyroid 
 ligaments. 10. Cornu minus of the thy- 
 roid cartilage. 11. Middle crico-thyroid 
 ligament. 12. Ligamentous portion of 
 the first ring of the trachea. 
 
 A FRONT VIEW OF THE LIGAMENTS 
 OF THE LARYNX. 1. Body of the os 
 hyoides. 2, 2. Its appendices. 3, 3. Its 
 cornua. 4, 5. Middle thyro-hyoid liga- 
 ment. 6, 6. Lateral thyro-hyoid liga- 
 ments. 7. Cornu majus of each half of 
 the thyroid cartilage. 8. Side of the 
 thyroid cartilage. 9. Its projecting 
 angle. 10. Middle crico-thyroid liga- 
 ment. 11. Crico-thyroid membrane. 
 12. Cornu minus of each side of the 
 thyroid cartilage. 13. First ring of 
 the trachea. 
 
 movements. Between the middle and lateral ligaments, 
 these cartilages are connected by quite a dense structure, 
 called the crico-thyroid membrane, Fig. 79 (i i). 
 
 The cricoid and arytenoid are connected by TWO CAPSULAK 
 LIGAMENTS, Fig. 78 (s, e), which contain synovial membranes. 
 These articulations allow of very free movement to the ary- 
 tenoid cartilages. 
 
 The CHORDS YOCALES, or THYRO-ARYTENOID LIGAMENTS, 
 Fig. 81 (6, 6), consist of two on each side, one above the other. 
 The inferior are sometimes called the true vocal ligaments, 
 on account of their containing much more fibrous structure 
 than the superior. They are composed of the yellow elastic 
 
OF THE LAEYNX. 
 
 199 
 
 tissue. The inferior are horizontal, while the superior are 
 slightly arched upwards and outwards. They arise from 
 
 Fig. 80. 
 
 Fig. 81. 
 
 A LATERAL VIEW OF THE 
 SAME. 1. Os hyoides. 2. Thy- 
 ro-hyoid membrane. 3. Cornu 
 majus of the thyroid cartilage. 
 4. Its angle and side. 5. Cornu 
 minus. 6. Lateral portion of the 
 cricoid cartilage. 7. Rings of 
 the trachea. 
 
 A VIEW OP THE LARYNX FROM ABOVE, 
 
 SHOWING THE TflYRO-ARYTENOID OR VoCAL 
 
 LIGAMENTS. 1. Superior edge of the larynx. 
 2. Its internal face. 3. Cornua inajora of 
 the thyroid cartilage. 4. Posterior face of 
 the cricoid cartilage. 5, 5. Arytenoid car- 
 tilages. 6, 6. Thyro-arytenoid ligaments. 
 7. Their origin within the angle of the thy- 
 roid cartilage. 8. Their terminations at the 
 bases of arytenoid cartilages. 9. The glottis. 
 10. Anterior part of the inferior surface of 
 the cricoid cartilages. 
 
 the angle of the thyroid cartilage, close to each other, and 
 are inserted, the inferior into the anterior processes at the 
 bases of the arytenoids, and the superior near their apices. 
 They diverge somewhat as they proceed backwards, giving 
 to the rima glottidis the shape of the letter V, with the angle 
 pointing forwards. The inferior are covered by mucous mem- 
 brane on their inner and upper surfaces, while the superior 
 are covered on their inner, lower, and "external surfaces. 
 
 The muscles of the larynx are small, and generally named 
 from the parts to which they are attached. The thyro-hyoideus 
 was described with the muscles of the neck. 
 
 The CKICO-THYEOIDEUS, Fig. 82 (3), is quite short, and of 
 a triangular shape. It arises from the anterior part of the 
 cricoid cartilage, by a narrow point, and passes upwards and 
 outwards to be inserted into the thyroid cartilage, occupying 
 
200 
 
 DISSECTION OF THE NECK. 
 
 the outer part of its lower border and inferior cormi. The 
 two thyro-hyoidei muscles leave a triangular space between 
 them, in which the middle crico-thyroid ligament is situated. 
 
 Fig. 83. 
 
 Fig. 83. 
 
 A FRONT VIEW OF THE CRICO-THY- 
 MUSCLES. 1. Thyroid cartilage. 
 2. Crieo-thyroid ligament. 3, 3. Crico- 
 thyroid muscles. 4. Origin of left. 5. 
 Insertion of right 6. First ring of the 
 trachea. 
 
 A POSTERIOR VIEW OF THE ARYTE- 
 NOID AND CRICO-ARYTENOID MUSCLES. 
 1,2,3. Thyroid cartilage. 4, 4. Sum- 
 mits of the arytenoid cartilages. 5, 5. 
 Insertions of arytenoid muscles. 6, 6. 
 Cricoid cartilage. 7. Its middle portion. 
 8, 9, 8, 9. Posterior crico-arytenoid mus- 
 cles. 10. Posterior portion of the tra- 
 chea. 11. Arytenoid muscles. 
 
 The CRICO-ARYTENOIDEUS POSTICUS, Fig. 83 (s), arises 
 from the posterior surface of the cricoid cartilage, passes 
 obliquely upwards and outwards to be inserted into a pro- 
 cess on the posterior and outer side of the base of the aryte- 
 noid cartilage. 
 
 The ARYTENOIDEUS, Fig. 83 (i i), consists of transverse and 
 oblique fibres. The latter are superficial, and extend from 
 the base of one cartilage to the apex of the other. The 
 former pass from the posterior surface of one cartilage to that 
 of the other. The last-named muscles are exposed by simply 
 removing the mucous membrane and some areolar tissue 
 which covers them posteriorly. 
 
 The THYRO-EPIGLOTTICI and ARYTENO-EPIGLOTTICI, are 
 composed of a few pale, muscular fibres, passing, the former 
 from the thyroid, and the latter from the arytenoid carti- 
 lages to the epiglottis, within the folds of mucous mem- 
 
OF THE LARYNX. 
 
 201 
 
 Fig. 84. 
 
 brane which extend between these cartilages. They are 
 more strongly developed in the larynx of some of the lower 
 animals. 
 
 The THYRO-ARYTENOIDEUS, Fig. 84(u),.is situated be- 
 tween the ala of the thyroid cartilage, and the vocal chords 
 and ventricle of the larynx. To expose this muscle, it is ne- 
 cessary to remove the posterior part 
 of one of the alas of the thyroid car- 
 tilage, by dividing it vertically a 
 short distance behind the median line, 
 and disarticulating it from the cricoid. 
 It is separated from the cartilage by 
 some loose areolar tissue, which must 
 be carefully dissected away. 
 
 The CRICO-ARYTENOIDEUS LA- 
 TER ALIS, Fig. 84 (is), may be ex- 
 posed by the same dissection. It 
 arises from the upper border of the 
 cricoid cartilage, just on the inside of 
 the surface on which rests the ala of 
 the thyroid cartilage, and passes 
 obliquely backwards to \Q inserted 
 into the base of the arytenoid. 
 
 The Mucous MEMBRANE of the 
 
 A VERTICAL SECTION OF THE 
 LARYNX TO SHOW SOME OP ITS 
 MUSCLES. 1. Cornu majus of 
 the thyroid cartilage. 2. Its 
 larynx is COntinUOUS through its superior border. 3. Section of 
 
 superior orifice with that of the 
 pharynx, and, through its lower 
 opening, with that of the trachea. It 
 
 follows all itS elevations and depreS- 12." Thyro-arytenoid muscle. 
 Sions. The lateral boundaries Of the 13 - Crico-arytenoideus latera- 
 
 glottis are formed by folds of this 
 membrane, which extend from the 
 arytenoid cartilages obliquely up- 
 wards and forwards to the sides of 
 the epiglottis, thus leaving an opening between them of a 
 triangular shape, with the base formed by the epiglottis. 
 There are quite a number of mucous glands in the larynx, 
 especially about the ventricles and glottis. 
 
 The VENTRICLES, Fig. 85 (9), of the larynx are two pouches, 
 one situated on each side of the rima glottidis, and lined 
 
 its body. 4. Its internal sur- 
 face. 5. Arytenoid cartilage. 
 6. Posterior surface of the 
 thyroid cartilage. 7, 8, 9. 
 Arytenoid muscles. 10, 11, 
 
 lis muscle. 14. Cricoid carti- 
 lage. 15,16,17. Crico-aryte- 
 noideus posticus. 18, 19. First 
 rings of the trachea as united 
 by ligament. 
 
202 
 
 DISSECTION OF THE NECK. 
 
 85 - 
 
 A VERTICAL SECTION OF THE 
 LARYNX, TO snow ITS INTERNAL 
 SURFACE. 1. Section of the root 
 of the tongue. 2. Os hyoides. 3. 
 The muciparous gland of the epi- 
 glottis. 4. Top of the epiglottic 
 cartilage. 5. A section of its an- 
 terior face. 6. A fold of mucous 
 membrane from the arytenoids to 
 the epiglottis. 7. Superior vocal 
 ligament. 8. Section of thyroid 
 cartilage. 9. Ventricle of Galen 
 or Morgagni. 10. Lower vocal 
 
 13. Its posterior por- 
 
 by mucous membrane. Each of 
 them is placed between the vocal 
 chords of its own side, especially 
 the superior, on the inside, and 
 the thyro-arytenoid muscle on the 
 outside. The sacculus laryngis is 
 a projection of the ventricle up- 
 wards on the outside of the supe- 
 rior cord. Several mucous glands 
 are found in these pouches, and 
 which are pressed upon by the 
 thyro-arytenoid muscles. 
 
 The KIMA GLOTTIDIS is the space 
 between the vocal chords of the two 
 sides. Its form was spoken of in 
 connection with the chords. This 
 orifice and the glottis are subject 
 to variations in size, but the infe- 
 rior, or tracheal, opening of the 
 larynx remains constantly the 
 same, being surrounded by the 
 cricoid cartilage. 
 
 There is, beneath the mucous 
 membrane around the glottis, an 
 abundance of loose areolar tissue. 
 In inflammation of these parts, se- 
 rum is effused in this areolar tis- 
 sue ; sometimes in sufficient qua* 
 tity to cause great difficulty in 
 
 cartilage. 
 
 tion. 14. Lining "membrane of respiration, or even death. 
 
 the trachea. 15. End of the cornu 
 majus of the os hyoides. 16. Cornu 
 
 Mucous membrane of the pha- 
 rynx. 18. (Esophagus. 19. Thy- 
 roid gland. 
 
 The arteries of the larynx are 
 
 majus of the thyroid cartilage. 17. derived from the superior and in- 
 ferior thyroid ; and it is abundantly 
 supplied from these sources with 
 arterial blood. 
 The veins terminate in those in the immediate vicinity. 
 Its nerves are the superior and inferior laryngeal branches 
 of the pneumogastric, and a branch of the hypoglossal. The 
 superior laryngeal enters the larynx either just above the 
 thyroid cartilage, or through a foramen in this cartilage. It 
 is distributed principally to the mucous membrane, although 
 it sends some filaments to the muscles. The inferior laryngeal. 
 
OF THE PHARYNX. 203 
 
 or recurrent branch, enters the larynx at its lower and poste- 
 rior part. It supplies, mainly, the muscles with involuntary 
 motor filaments. The hypoylossal branch furnishes the laryn- 
 geal muscles with voluntary motor filaments. 
 
 SECT. IV. DISSECTION OF THE PHARYNX. 
 
 The pharynx should be distended with hair, or something 
 which may be had conveniently, for the dissection of its 
 muscles. It is reached with more facility if the cervical ver- 
 tebrae be first removed, or if a transverse vertical section of 
 the cranium be made just in front of the occipital foramen. 
 If the student has an opportunity to dissect but a single sub- 
 ject, he should not sacrifice a good view of the topography 
 of the interior of the pharynx, for the sake of getting a 
 more distinct idea of its muscles by a special dissection. 
 
 The following are the five muscles which enter more or 
 less into the composition of its muscular walls: 
 
 The INFERIOR CONSTRICTOR, Fig. 86 (7), and Fig. 87 (9), 
 arises from the upper ring of the trachea, the cricoid cartilage, 
 and the posterior part of the ala of the thyroid ; the fibres 
 radiate as they pass backwards to be inserted into the raphe', 
 which is common to the constrictors of both sides. The 
 lower fibres are nearly horizontal in their direction, and cor- 
 respond to the superior circular fibres of the oesophagus. 
 The superior fibres are oblique, and overlap the lower part 
 of the middle constrictor. 
 
 The MIDDLE CONSTRICTOR, Fig. 86 (e), arises from the 
 cornua of the hyoid bone, and from the stylo-hyoid ligament ; 
 its fibres radiate backwards, and are inserted into the raphe. 
 The upper fibres overlap the lower portion of the superior 
 constrictor, from which they are separated by the stylo- 
 pharyngeus muscle, and the glosso-pharyngeal nerve. It is 
 connected to the base of the skull by the pharyngeal apo- 
 neurosis. 
 
 The SUPERIOR CONSTRICTOR, Fig. 86 (s) r arises from seve- 
 ral points, as the internal pterygoid plate, the pterygo-max- 
 illary ligament, and the mylo-hyoid ridge of the inferior 
 maxilla. Its fibres pass backwards to be inserted into the 
 raphe, and also to be connected with the pharyngeal aponeu- 
 
204 DISSECTION OF THE KECK. 
 
 rosis. There is quite a space between its upper border on 
 each side, and the base of the cranium, which is occupied by 
 the pharyngeal aponeurosis. 
 
 The STYLO-PHARYNGEUS, Fig. 86 (i i), as its name implies, 
 extends from the styloid process to the pharynx. Its fibres 
 
 Fig. 86. 
 
 A POSTERIOR VIEW OF THE MUSCLES OF THE EXTERNAL PORTION OF THE PHA- 
 RYNX, AS SHOWN BY REMOVING THE BACK OF THE HEAD AND THORAX. 1. Basilar 
 
 portion of the sphenoid bone. 2. Inferior anterior portion of the os frontis, and 
 crista Galli of the ethmoid. 3, 3. Petrous portions of temporal bones. 4. Levator 
 palati muscle. 5. Constrictor pharyngis superior. 6. Constrictor pharyngis me- 
 dius. 7. Constrictor pharyngis inferior. 8. Upper part of posterior face of the 
 lining membrane of pharynx, after removing the muscle. 9. Longitudinal muscu- 
 lar fibres of the oesophagus. 10. Internal pterygoid muscle. 11. Stylo-pharyngeus. 
 12. Myloid attachment of the constrictor pharyngeus superior. 13. Stylo-hyoideus. 
 14. Temporal belly of digastricus. 15. Platysma myoides muscle. 16. Sterno- 
 cleido-mastoideus. 17. Omo-hyoideus. 18. Sterno-thyroid muscle. 19. Sterno- 
 hyoid. 20. Section of sterno-thyroideus. 21. Section of the trapezius muscle. 
 
 enter the pharynx between the superior and middle constric- 
 tors, some of them to be inserted into the posterior border of 
 tne thyroid cartilage, and others to be lost in the pharynx. 
 
 The PALATO-PHARYNGEUS belongs partly to the soft palate, 
 and partly to the pharynx. It arises from the posterior 
 
OF THE PHARYNX. 
 
 205 
 
 border of the ala of the thyroid cartilage, passes upwards to 
 form the posterior half-arch of the palate, and then spreads 
 out to be inserted into the median line of the palate, with 
 its fellow on the opposite side. 
 
 Fig. 87. 
 
 A SIDE VIEW OF THE MUSCLES OP THE 
 
 PHARYNX. 1. The trachea. 2. The cri- 
 coid cartilage. 3. The crico-thyroid mem- 
 brane. 4. The thyroid cartilage. 5. The 
 thyro-hyoidean membrane. 6. The os hyoi- 
 des. 7. The stylo-hyoidean ligament. 8. 
 The oesophagus. 9. The inferior constrictor. 
 10. The middle constrictor. 11. The supe- 
 rior constrictor. 12. The stylo-pharyngeus 
 muscle passing down between the superior 
 and middle constrictor. 13. The upper con- 
 cave border of the superior constrictor ; at 
 this point the muscular fibres of the pha- 
 rynx are deficient. 14. The pterygo-maxil- 
 lary ligament. 15. The buccinator muscle. 
 16. The orbicularis oris. 17. The mylo-hy- 
 oideus. 
 
 The PHARYNGEAL APONEUROSIS is thick and strong at the 
 upper part of the pharynx, where it serves to connect its 
 muscular walls to the base of the cranium, and to complete 
 them in this part of it. As it descends, it gradually becomes 
 thinner, until it ends in areolar tissue. It is situated between 
 the mucous membrane and muscular layer. 
 
 The arteries of the pharynx are obtained principally from 
 the ascending pharyngeal; it also receives small branches 
 from, the superior thyroid, the palatine and the pharyngeal 
 branches of the internal maxillary. 
 
 The nerves come from the pharyngeal plexus, which con- 
 sists of sensor and involuntary motor filaments derived from 
 the glosso-pharyngeal, pneumogastric, and sympathetic. 
 
 The pharynx is separated from the vertebrae by the longus 
 colli and rectus capitis anticus major muscles. 
 
 The anatomy of the trachea and resophagus will be 
 described, the former in connection with the bronchi and 
 lungs, and the latter with the contents of the mediastinum. 
 18 
 

PART II. 
 
 DISSECTION OF THORAX, BACK, AND UPPER EXTREMITY. 
 
 CHAPTEK I. 
 
 THE UPPEK EXTEEM1TY. 
 
 SECT. I. DISSECTION OF THE PECTOBAL AND AXILLAKY 
 EEGIONS. 
 
 BEFOEE commencing the dissection of these parts, the stu- 
 dent should make himself familiar with the prominent points 
 around the shoulder and axilla. He should also notice the 
 outlines of the thorax, the regions into which it is divided 
 for the purposes of auscultation and percussion, the position 
 of the mammae, and the degree in which these various regions 
 are subcutaneous or covered by muscles. 
 
 It will be perceived that the sternum is partly subcuta- 
 neous, also the clavicle, with the acromion process, and spine 
 of the scapula. The position of the coracoid process of the 
 scapula should be ascertained, and its relations to the clavicle 
 and acromion process carefully observed. The position of 
 the upper extremity should be varied so as to show the move- 
 ments of the clavicle and scapula, and any changes which 
 may occur in the general configuration of the parts. 
 
 An incision may now be made through the skin and super- 
 ficial fascia, commencing at the middle of the upper border 
 of the sternum, and extending along the clavicle to the acro- 
 mion process. Another may then be made along the median 
 line of the sternum, to the xiphoid cartilage; and a third from 
 the sterno-clavicular articulation, to the insertion of the pec- 
 toralis major. The skin may now be raised by reflecting one 
 flap towards the shoulder, and the other towards the lower 
 border of the pectoralis major. In case the abdomen is being 
 
208 
 
 THE UPPER EXTREMITY. 
 
 dissected at the same time, it may be convenient to carry the 
 last incision from the xiphoid cartilage along the lower 
 border of the pectoral muscle, since the parts belonging to 
 both the upper and lower extremities are here more or less 
 blended. In this way the same incision, as far as the origin 
 of the pectoralis major is concerned, will answer for both. 
 The portion of skin covering the serratus magnus may 
 be left till the student is ready to dissect the axilla, when it 
 may be reflected off in a single flap. 
 
 The integument of the pectoral region demands no particu- 
 lar notice. 
 
 Its nerves are derived partly from the supra-clavicular, Fig. 
 103 (i), and supra-acromial, Fig. 104 (i), branches of the 
 cervical plexus, which descend from the neck over the cla- 
 vicle and sternum, and partly from the anterior cutaneous 
 branches of the intercostals, which perforate the intercostal 
 spaces along the border of the sternum, and ramify in the 
 subcutaneous fascia ; a branch of the second intercostal nerve 
 anastomoses with a branch of the supra-clavicular. 
 
 The cutaneous arteries come from the internal mammary, 
 and from the thoracic branches of the axillary. The largest 
 of them are distributed to the mammary gland. 
 
 There is only one vein of any importance superficial to 
 the deltoid and pectoralis major muscles, 
 and this is the cephalic, which occupies 
 the groove corresponding to the juxta- 
 position of these muscles. In removing 
 the skin and fascia, the student should 
 look for this vein and the humeral 
 branch of the thoracico-acromial artery 
 which accompanies it. 
 
 The MAMMARY GLAND, Fig. 88, should 
 be examined in situ: its lobulated ar- 
 rangement ; its appearance as contrasted 
 with the surrounding tissues ; the man- 
 ner in which it is connected with the 
 fascia, and its relations to the pectoralis 
 major and the thorax generally. 
 
 Its arteries and nerves are derived 
 from the same sources as those of the 
 skin in its vicinity. Its lymphatics are connected with those 
 
 Fig. 88. 
 
 A SIDE VIEW OP THE 
 MAMMARY GLAND. 
 
DISSECTION OF THE AXILLAKY REGION. 
 
 209 
 
 Fig. 89. 
 
 of the axilla, and also with others in the cavity of the 
 thorax. 
 
 The size of the gland varies greatly. In the female it is 
 much larger than in the male. The nipple is situated a little 
 to the inner side of the centre. It is surrounded by an are- 
 ola, the tint of which, in the female, depends on several cir- 
 cumstances, as complexion, menstruation, 
 pregnancy, &c. The surface of the mam- 
 ma appears smooth, the spaces between 
 the lobules being filled with fat. There 
 is not, however, usually much fat beneath 
 the skin around the nipple. 
 
 The lactiferous tubes, Fig. 89, in the nipple, 
 vary from fifteen to twenty-three or four. 
 These tubes are wholly independent of 
 each other ; so, also, are the various smaller 
 ducts of the different lobules, which pro- 
 ceed from the radicles, and unite to form 
 them ; hence, if one of these tubes shall 
 become closed during lactation, the milk 
 will necessarily be accumulated in all the 
 smaller tubes of which that is a common 
 outlet. 
 
 There are small glands on and around 
 the nipple, for the purpose of supplying a 
 lubricating secretion. 
 
 The importance of supporting the mam- 
 ma3 during lactation, and especially if suf- 
 fering from inflammation, will be suggested 
 by their position and means of attachment 
 to the thorax. 
 
 A VERTICAL SEC- 
 TION OF THE MAMMARY- 
 GLAND, SHOWING ITS 
 THICKNESS AND THE 
 ORIGINS OF THE LAC- 
 TIFEROUS DUCTS. 1, 
 2, 3. Its pectoral sur- 
 face. 4. Section of the 
 skin on the surface of 
 the gland. 5. The thin 
 skin covering the nip- 
 ple. 6. The lobules 
 and lobes composing 
 the gland. 7. The lac- 
 tiferous tubes coming 
 from the lobules. 8. 
 The same tubes col- 
 lected in the nipple. 
 
 There is generally very little fat in the 
 subcutaneous fascia or areolar tissue in this 
 region. 
 
 The deep or special fasciae consist of one investing the pecto- 
 ralis major, and another covering the deltoid. The pectoral 
 fascia is continuous from the lower border of the great pecto- 
 ral muscle, across the axilla to the latissimus dorsi ; also with 
 the fascia of the arm. Externally, it dips down between the 
 deltoid and pectoralis major muscles, along with the deltoid 
 fascia, which is inserted below into the deltoid ridge, and is 
 
210 THE UPPER EXTREMITY. 
 
 continuous behind with the infra-spinata fascia and that of 
 the arm or the brachial fascia. These fasciae should be studied 
 with reference more particularly to the formation of abscesses 
 beneath them. 
 
 The deep fascia may now be raised by making an incision 
 through it from the sterno-clavicular articulation to the in- 
 sertion of the pectoralis major. The student, in this way, 
 will be able to raise the fascia so as to trace its continuity as 
 described above, at the same time that he exposes the pecto- 
 ralis major. The deltoid fascia may be raised in the same 
 manner from the deltoid muscle, although it will be sufficient 
 to expose only the anterior half of this muscle at the present 
 time. 
 
 The PECTORALIS MAJOR, Fig. 90 (7, i o), arises from the 
 inner half of the clavicle, the anterior surface of the sternum, 
 the cartilages of the second, third, fourth, fifth, and sixth 
 ribs, and by a slip from the aponeurosis of the external ob- 
 lique. From this broad origin the fibres converge, and are 
 inserted, by a flat tendon, into the anterior margin of the 
 bicipital groove on the humerus, and into the brachial fascia. 
 From the extensive origin and narrow insertion of this mus- 
 cle, the student will see the necessity of the difference which 
 exists in the direction of its fibres, and the effects of different 
 portions of the muscle acting separately. The lower fibres 
 are nearly horizontal, while the upper are vertical in their 
 direction. The upper part of the muscle is inserted lower 
 down than the inferior portion, which causes a sort of 
 doubling of the tendon. The action of this muscle varies; 
 if the clavicular portion alone acts, it will draw the arm up- 
 wards and forwards, the sternal will move it directly forwards, 
 while the lower part will draw it downwards and forwards ; 
 the entire muscle will bring the arm inwards and forwards. 
 If the humerus be elevated and fixed, then the lower part of 
 the muscle will raise the ribs and draw them outwards so as 
 to assist in expanding the thorax. If the hand be supined, 
 it is capable of pronating it by rotating the humerus inwards. 
 The clavicular portion is usually separated from the costo- 
 sternal by areolar tissue. This fissure is sometimes quite 
 large, and extends some distance towards the insertion of the 
 muscle ; again, it is scarcely perceptible. An areolar inter- 
 space also separates this muscle from the deltoid. In this 
 
DISSECTION" OF THE AXILLARY REGION. 
 
 211 
 
 space are found the cephalic vein and the humeral branch, Fig. 
 94, of the thoracico-acromial artery. 
 
 Fig. 90. 
 
 A VIEW OF THE SUPERFICIAL MUSCLES OF THE UPPER FRONT OF THE TRUNK. 
 1. Sterno-hyoid. 2. Sterno-cleido-mastoid. 3. Sterno-thyroid. 4. Clavicular 
 portion of the sterno-cleido-mastoid. 5. Anterior edge of the trapezius. 6. Clavicle. 
 7. Clavicular origin of the pectoralis major. 8. Deltoid. 9. Fold of fibres of the 
 pectoralis major on the anterior edge of the axilla. 10. Middle of the pectoralis 
 major. 11. The crossing and interlocking of the fibres of the external oblique of 
 one side of the abdomen with those of the other. 12. Biceps flexor cubiti. 13. 
 Teres major. 14. Serratus magnus anticus. 15. Superior heads of the external 
 oblique interlocking with the serratus magnus. 
 
 The pectoralis major may now be raised from its origin, 
 taking care to observe the nerves and arteries which pene- 
 trate its under surface. 
 
 The nerves come from the axillary, and consist of one or 
 two branches, called the superior thoracic. Fig. 93. The arteries 
 are branches of the superior thoracic and thoracica acroinialis, 
 Fig. 92, which arise, most frequently, by a common trunk, 
 from the axillary artery. The pectoralis major should be 
 
212 THE UPPER EXTREMITY. 
 
 raised with a view of replacing it so as to study its relations 
 to the axilla. 
 
 Instead of detaching the entire muscle from its origin, the 
 student may turn down the clavicular portion at first, and 
 dissect down to the axillary vessels and nerves, which will 
 afford him a good view of the surgical relations of the upper 
 part of the axillary artery. In this way, he will be able to 
 obtain a correct idea of its depth, and what parts are neces- 
 sarily involved in cutting down upon it just below the cla- 
 vicle. In doing this, the following parts will be seen : 
 
 Having turned the clavicular portion of the pectoralis 
 major down to the extent of about three inches, the costo- 
 clavicular aponeurosis will be brought into view. This is at- 
 tached to the first rib, the clavicle, and the coracoid process, 
 and is reflected downwards over the pectoralis minor. 
 
 Coming through this fascia, and close to the upper border 
 of the pectoralis minor, will be observed the superior thoracic 
 and thoracico-acrom'ial arteries, Fig. 92 (11,12); the first going 
 to the pectoralis major, and the last towards the deltoid 
 muscle, to divide into its acromial, humeral, and thoracic 
 branches. The acromial branch is distributed to the parts in 
 the neighborhood of the acromion process ; the humeral enters 
 the fissure between the deltoid and pectoralis major, to be 
 distributed principally to the former muscle; the thoracic 
 branch goes to the latter muscle. These arteries send branches 
 to the skin and fascia crossing the muscles. 
 
 The SUPERIOR THORACIC NERVE, which arises behind the 
 clavicle, perforates this fascia, and accompanies the artery of 
 the same name to the pectoralis major. 
 
 The CEPHALIC VEIN, after passing up in the groove be- 
 tween the deltoid and pectoralis major to near the clavicle, 
 dips beneath the latter muscle, and passes transversely across 
 to terminate in the axillary vein, which lies close to the tho- 
 rax, Fig. 94. There are other veins in this region which 
 open either into the cephalic, or directly into the axillary, 
 but they are small, and have no practical importance. 
 
 Eemoving the fascia and areolar tissue, the upper border 
 of the pectoralis minor below, and the subclavius muscle, Fig. 
 91 (s, 12), above, will be seen separated by a space somewhat 
 triangular in shape. In this space, and occupying a plane 
 deeper than these muscles, are the axillary vein, artery, and 
 
DISSECTION OF THE AXILLARY REGION. 213 
 
 nerves, Figs. 93, 94. The artery is situated between the vein 
 on its thoracic side, and the nerves on its humeral side. 
 The artery is deeper seated than the vein, and the nerves are 
 situated on a plane deeper than it. 
 
 In making this dissection, there is nothing destroyed which 
 the student will have any occasion to examine afterwards ; 
 nor is it so complex as to prevent any one from making it, if 
 he will exercise a little patience ; and, when finished, he will 
 have the satisfaction of seeing at once how the knowledge 
 which he has acquired can be applied in practice ; for he can 
 now tell, from his own observation, which parts would have 
 to be divided, what parts should be avoided, and how deep 
 an incision would be required to reach the axillary artery in 
 the upper part of its course. He has now a picture fixed in 
 his mind, made up of several details, which sustain a certain 
 relation to each other, and all of them to the main object in 
 the whole group or picture. He will not be likely to forget 
 the special anatomy of parts when their surgical relations are 
 thus fixed in his mind. He sees, for instance, the clavicular 
 portion of the pectoralis major, the manner in which it covers 
 the pectoralis minor and the subclavius, with the space 
 between them ; how this space is filled up with a fascia which 
 is perforated by small vessels and nerves; how the great 
 arterial trunk, which is destined to supply nearly the whole 
 of the upper extremity with arterial blood, enters the axilla; 
 how the great venous trunk, which is required to return this 
 blood, leaves the axilla;- and how the nerves enter the same 
 space preparatory to dividing and subdividing to go to every 
 part of the upper extremity. 
 
 The pectoralis major having been separated from its con- 
 nections, except its insertion, the pectoralis minor now comes 
 into view. 
 
 The PECTORALIS MINOR, Fig. 91 (12), arises from the se- 
 cond, third, fourth, and fifth ribs, sometimes from but three, 
 and is inserted tendinous, into the coracoid process, near its free 
 extremity. Its tendon is connected with the coraco-brachialis 
 and short head of the biceps, and frequently by a fibrous 
 band with the triangular, or capsular, ligament of the shoulder 
 joint. It forms a part of the anterior wall of the axilla, 
 leaving a space above and below to be formed by the pecto- 
 
214 
 
 THE UPPER EXTREMITY. 
 
 rails major, the fibres of which it crosses nearly at a right 
 angle. By observing its attachments, and the direction of 
 its fibres, it will be seen that it can draw the scapula down- 
 wards, forwards, and inwards ; or when the shoulder is carried 
 upwards and backwards, and fixed in this position, it can 
 elevate the ribs from which it takes its origin. Thus by 
 placing the arm and shoulder in a proper position, both the 
 pectoral muscles become powerful agents in expanding the 
 upper part of the thorax. 
 
 In raising this muscle, the dissector should look for the 
 inferior thoracic artery and nerve, Figs. 92, 98, which penetrate 
 its under surface. The nerve is quite small, and comes from 
 the plexus behind the muscles, and passes between the axil- 
 lary artery and vein. This artery varies very much in its 
 origin, as do all the branches of the axillary artery. 
 
 Fig. 91. 
 
 A VIEW OP THE DEEPER- 
 SEATED MUSCLES ox THE 
 UPPER FRONT OP THE 
 TRUNK. 1. Cut portion of 
 thesterno-cleido-mastoid. 2. 
 Scalenus inedius. 3. Scale- 
 nus anticus. 4. Trapezius. 5. 
 Omo-hyoid. 6. Sterno-thy- 
 roid. 7. Sterno-hyoid. 8. 
 Subclavius muscle. 9. First 
 external intercostal. 10. In- 
 sertion of the pectoralis mi- 
 nor. 11. Cut portion of the 
 coraco-brachialis and short 
 head of the biceps. 12. Body 
 of the pectoralis minor. 
 13. An external intercostal 
 muscle. 14. Subscapularis. 
 15. Latissimus dorsi. 16. 
 Serratus magnus. 
 
 The SUBCLAVIUS MUSCLE, Fig. 91 (s), arises tendinous from 
 the cartilage of the first rib, and is inserted into the under 
 
DISSECTION OF THE AXILLARY EEGION. 215 
 
 surface of the outer part of the clavicle. It can draw the 
 acromial extremity of the clavicle downwards and forwards, 
 thus assisting other muscles in moving the shoulder in this 
 direction ; or when the shoulder is fixed in an opposite direc- 
 tion, it can assist in elevating the ribs. This muscle is placed 
 between two layers of the costo-clavicular aponeurosis. Its 
 relation? -&? the axillary vessels and nerves should be ob- 
 served. 
 
 The AXILLA is now fairly exposed, the whole of its ante- 
 rior wall being removed. The beginner will be able to 
 dissect and study, at kast, the principal vessels and nerves, 
 preparatory to a more thorough investigation of its contents, 
 in his future dissections of this region. 
 
 Some of the lymphatic glands may be looked for before 
 proceeding to dissect the vessels and nerves. There are 
 several of these glands situated just behind the lower border 
 of the pectoralis major, which are connected with the lym- 
 phatics of the mammary gland. Another chain is found at 
 the border of the latissimus dorsi ; and others are scattered 
 through the axilla. Not unfrequently these glands are met 
 with in the dissecting-room enlarged from disease. 
 
 In dissecting the vessels and nerves of the axilla, much 
 may be done with the handle of the scalpel. They are im- 
 bedded in loose areolar tissue, which can be separated from 
 them without much cutting. A good deal of this can be 
 done by introducing the scissors at different points with the 
 blades shut, and then opening them ; in this way there is no 
 danger of cutting anything, and when properly done, no 
 occasion for breaking any of the vessels or nerves. 
 
 The AXILLARY ARTERY, Fig. 92 (9), extends from the 
 first rib to the lower border of the tendon of the pectoralis 
 major. It is a continuation of the subclavian. Its direction 
 varies with the position of the arm. When the arm is de- 
 pendent, it forms nearly a right angle with the subclavian ; 
 but when the arm is elevated to a right angle with the body, 
 it forms nearly a straight line with that artery. The recol- 
 lection of this fact may be of some importance in keeping 
 the arm in a proper position, in reducing luxations of the 
 humerus, especially if sufficient time has elapsed for adhe- 
 sions to be formed. 
 
216 
 
 THE UPPEE EXTREMITY. 
 
 This artery may be divided into three portions : one above 
 the pectoralis minor, one below it, and another directly be- 
 hind it. The relations of the upper division have already 
 been described. In the middle part of its course it is sur- 
 
 Fig. 92. 
 
 1. The deltoid muscle. 2. The biceps. 
 3. The tendinous process given off from the 
 tendon of the biceps to the deep fascia of 
 the forearm. It is this process which sepa- 
 rates the median basilic vein from the bra- 
 chial artery. 4. The outer border of the 
 brachialis anticus muscle. 5. The supinator 
 longus. 6. The coraco-brachialis. 7. The 
 middle portion of the triceps muscle. 8. 
 Its inner head. 9. The axillary artery. 10. 
 The brachial artery; a dark line marks the 
 division between these two vessels. 11. The 
 thoracica acromialis artery dividing into 
 its three branches; the number rests upon 
 the coracoid process. 12. The superior and 
 inferior thoracic arteries. 13. The serratus 
 magnus muscle. 14. The subscapular artery. 
 The posterior circumflex and thoracica axil- 
 laris branches are seen in the figure between 
 the inferior thoracic and subscapular. The 
 anterior circumflex is observed, between the 
 two heads of the biceps, crossing the neck 
 of the humerus. 15. The superior profunda 
 artery. 16. The inferior profunda. 17. The 
 anastomotica magna inosculating inferiorly 
 with the anterior ulnar recurrent. 18. The 
 termination of the superior profunda, inos- 
 culating with the radial recurrent in the in- 
 terspace between the brachialis anticus and 
 supinator longus. 
 
 rounded by the axillary plexus, Fig. 93, and is never ligated 
 at this point unless in cases of amputation. 
 
 The lower division is the most superficial. It can be 
 reached here very readily from the axillary fossa. At first it 
 usually lies between two roots of the median nerve, and then 
 behind and a little to the thoracic side of this nerve. The 
 external cutaneous nerve is situated on its outer side, between 
 it and the coraco-brachialis muscle, which it very soon per- 
 forates. The internal cutaneous is seen on its inner side. This 
 nerve is quite small, and should not be confounded with the 
 
DISSECTION OF THE AXILLARY REGION. 
 
 217 
 
 lesser internal cutaneous, which lies close to it on the inner 
 side. The ulnar is just behind the internal cutaneous, and 
 to the inside of the artery ; this is about the size of one of 
 the roots of the median nerve. Behind the ulnar nerve, and 
 partly behind the artery, is the musculo-spiral nerve. This is 
 quite as large as the median nerve. The circumflex nerve is 
 directly behind the artery. If the student will make the 
 
 Fig. 93. 
 
 A VIEW OF THE BRACHIAL 
 PLEXUS OP NERVES AND BRAN- 
 CHES TO THE ARM. 1, 1. The 
 scalenus anticus muscle, behind 
 which are the roots of the plexus. 
 2,2. The median nerve. 3. The 
 ulnar nerve. 4. The branch to 
 the biceps muscle. 5. The nerve 
 of Wrisberg. 6. The phrenic 
 nerve from the 3d and 4th cer- 
 vical. 
 
 artery his guide, he will have no difficulty in finding and 
 distinguishing these six nerves, or divisions of the axillary 
 plexus. They are described here because the dissection of 
 the artery necessarily involves them, while the dissection of 
 the nerves exposes the artery. 
 
 The axillary artery is usually represented as giving off 
 19 
 
218 THE UPPER EXTREMITY. 
 
 in all seven branches. These are named the superior and 
 inferior thoracic, the thoracica acromialis, the thoracica axil- 
 laris, the subscapular, and the anterior and posterior cir- 
 cumflex. The first named four are very icregular in their 
 origin. The superior thoracic and the thoracica acromialis 
 usually have a common origin just behind the upper border 
 of the pectqralis minor. The distribution of these has 
 already been described. The inferior thoracic and the tho- 
 racica axillaris require no special notice. The three remain- 
 ing branches are more regular in their origin. 
 
 The SUBSCAPULAR, Fig. 92 (i 4), usually arises opposite the 
 lower border of the subscapularis muscle ; it may come off 
 higher up, or it may arise in common with some other artery. 
 It runs a* short distance on the lower part of the subscapu- 
 laris, when it gives off a large branch to go to the dorsum of 
 the scapula; this is the arteria dorsalis scapulae. It then con- 
 tinues downwards and backwards on the posterior wall of 
 the axilla to be distributed to the subscapularis, teres major, 
 latissimus dorsi, and serratus magnus. 
 
 The ANTERIOR CIRCUMFLEX may consist of one or two 
 small branches, and frequently comes from the posterior cir- 
 cumflex. It passes transversely outwards beneath the coraco- 
 brachialis, biceps, and deltoid muscles, and over the anterior 
 part of the surgical neck of the humerus. It is distributed 
 to the muscles above mentioned, and to the shoulder-joint. 
 
 The POSTERIOR CIRCUMFLEX is much larger. It passes 
 behind the surgical neck of the humerus, and thus reaches 
 the under surface of the deltoid, to which it is principally 
 distributed. The student will not be able to trace these 
 arteries, for the present, beyond the axilla. 
 
 The AXILLARY VEIN, Fig. 94 (2), lies to the thoracic side 
 of the artery in the upper part of the axilla, but gets some- 
 what in front of it in the lower part. The cephalic vein ter- 
 minates in it just below the clavicle; the basilic opens into 
 it in the lower part of the axilla; sometimes the axillary 
 vein seems to be a continuation of the basilic. The basilic 
 may join the venae comites before it reaches the axilla. 
 There are other veins which empty into the axillary ; they 
 correspond to the arteries which have been described, and 
 require no particular notice. 
 
DISSECTION OF THE AXILLARY REGION. 
 
 219 
 
 Fig. 94. 
 
 Besides the thoracic nerves and the divisions of the axil- 
 lary plexus, there are two or three 
 subscapular branches, the long tho- 
 racic or external respiratory nerve 
 of Bell, and the nerve of Wrisberg, 
 to be noticed in this dissection, 
 Fig. 93. 
 
 The SUBSCAPULAR arise from the 
 outer part of the plexus, and rest 
 on the subscapularis muscle, which, 
 together with the teres major and 
 latissimus dorsi, they supply. 
 
 The LONG THORACIC arises from 
 the fifth and sixth cervical, and at 
 first lies behind the axillary plexus, 
 then gets between it and the serratus 
 magnus, on which it rests as it de- 
 scends, vertically, nearly to its lower 
 border. It sends filaments to this 
 muscle throughout its course. Ke- 
 collecting its relations to the serratus 
 magnus, the dissector cannot well be 
 at a loss in finding it. 
 
 The LESSER INTERNAL CUTANEOUS 
 is a branch of the axillary plexus. 
 It is sometimes called the nerve of 
 Wrisberg. At first it is behind the 
 axillary vein, but soon gets to the 
 inner side of it, when it gives off 
 one or more branches to anastomose 
 with the intercosto-humeral. It then 
 passes down the arm on the inner side 
 of the basilic vein, pierces the fascia 
 
 THE SUPERFICIAL VEINS ON THE FRONT OP THE UPPER EXTREMITY. 1. Axil- 
 lary artery. 2. Axillary vein. 3. Basilic vein, where it enters the axillary. 4, 4. 
 Portion of the basilic vein which passes under the brachial fascia: a portion of the 
 vein is freed from the fascia. 5. Point where the median basilic joins the basilic 
 vein. 6. Points to the posterior basilic vein. 8. Anterior basilic vein. 9. Point 
 where the cephalic enters the axillary vein. 10. A portion of the same vein as 
 seen under the fascia; the rest is freed from it. 11. Point where the median ce- 
 phalic enters the cephalic vein. 12. Lower portion of the cephalic vein. 13. Me- 
 dian cephalic vein. 14. Median vein. 15. Vena communicans. 16. Cephalica- 
 pollicis vein. 17. Subcutaneous veins of the fingers. 18. Subcutaneous palmar 
 veins. 
 
220 
 
 THE UPPEE EXTREMITY. 
 
 some distance above the elbow, and is distributed to the skin 
 on the inner side of the arm. 
 
 The iNTERCOSTO-HuMERAL is a branch of the second inter- 
 costal nerve ; it enters the axilla by perforating the intercostal 
 muscles in the second intercostal space, about midway between 
 the sternum and the vertebral column. It traverses the lower 
 and posterior part of the axilla, and is distributed to the in- 
 tegument of the upper, inner, and posterior part of the arm. 
 It is connected, as before mentioned, to the lesser internal 
 cutaneous nerve, by one or more filaments. Several other 
 small cutaneous branches may also be observed when a careful 
 dissection of the axilla is made. 
 
 Besides the intercosto-humeral nerve, just described, several 
 of the posterior cutaneous branches of the intercostal nerves will 
 be met with in this dissection. They are, however, quite 
 small. They perforate the intercostal muscles below the 
 second intercostal space, and are lost in the integument. 
 
 The SERRATUS MAGNUS, Fig. 95 (5, e, 7), is a very broad 
 
 Fig. 95. 
 
 A LATERAL VIEW or THE DEEP- 
 SEATED MUSCLES OP THE TRUNK. 
 1. Vertebra. 2. First rib. 3. 
 Superior origin of the serratus 
 magnus. 4. Acromion scapulae. 
 5, 6, 7. Show the convergence of 
 the fibres of the serratus magnus 
 and its insertion into the whole 
 base of the scapula. 8. An ex- 
 ternal intercostal muscle. 9. Sec- 
 tion of the sacro-lumbalis. 10. 
 Transversalis abdominis. 11. Ab- 
 dominal aponeurosis. 12. Rectus 
 abdominis. 13. Fascia lumborum. 
 14, 14. Costal origins of the ser- 
 ratus magnus. 15. External in- 
 tercostal muscle. 16, 16. Two 
 internal intercostal muscles. 
 
DISSECTION OF THE AXILLARY REGION. 221 
 
 muscle, forming the inner or thoracic wall of the axilla. It 
 arises from the superior nine ribs by as many fleshy digita- 
 tions, the inferior four or five of which project in between the 
 heads of the external oblique, and is inserted into the whole 
 length of the base of the scapula. The lower fibres pass up- 
 wards and backwards, while the upper fibres have nearly a 
 horizontal direction. This muscle is capable of acting either 
 on the ribs or the scapula. When the ribs are fixed, it draws 
 the scapula forwards. If the lower or upper part act separ- 
 ately, it will rotate the scapula on its axis. If the shoulder 
 be carried backwards and fixed in this position, this muscle, 
 especially the lower part of it, will elevate the ribs, thus co- 
 operating with other muscles in expanding the thorax. That 
 portion of it which arises from the second, third, and fourth 
 ribs, is quite thin. Between it and the ribs and intercostal 
 muscles is an abundance of loose areolar tissue, which allows 
 of a free gliding movement. This muscle should not be 
 divided until the dissector is ready to detach the arm from 
 the trunk. It is not very easy to make a clean dissection of 
 the serratus magnus unless the clavicle is disarticulated from 
 the sternum, and detached from the first rib, so that the scap- 
 ula can be drawn backwards and separated widely from the 
 thorax. 
 
 The SUBSCAPULARIS arises. Fig. 96 (19), from the whole 
 of the thoracic surface of the scapula ; the fibres converge as 
 they pass upwards and forwards to form a short tendon, which 
 is inserted into the lesser tuberosity of the humerus. It passes 
 beneath the coracoid process, and over the neck of the hu- 
 merus, its tendon being blended more or less intimately with 
 the capsular ligament of the shoulder-joint. Between the 
 tendon and neck of the humerus is a large bursa, which 
 frequently communicates with the joint. Sometimes there 
 are two or three intermuscular septa, which seem to divide 
 the muscle into three or four parts. It assists in keeping the 
 head of the humerus applied to the glenoid cavity ; or, it can 
 draw the arm to the thorax, or rotate the humerus inwards. 
 The action of the muscles around the shoulder-joint should 
 be studied, when they have all been dissected, as constitut- 
 ing a group. 
 
 The TERES MAJOR arises, Fig. 96 (14), from a flat surface 
 near the inferior angle of the scapula ; it passes forwards, and 
 
222 THE UPPER EXTREMITY. 
 
 somewhat upwards, and is inserted, by a broad thin tendon, 
 into the posterior part of the bicipital groove of the humerus. 
 
 Fig. 96. 
 
 AN ANTERIOR VIEW OF THE 
 MUSCLES OF THE SHOULDER. 
 1. Upper part of the body of the 
 scapula. 2. Supra-spinatus mus- 
 cle. 3. Section of acromion pro- 
 cess. 4. Coracoid process. 5. 
 Origin of the second or short 
 head of the biceps. 6. Subsca- 
 pularis near its insertion. 7. 
 Deltoid. 8. Tendon of the pec- 
 toralis major. 9. Insertion of 
 the deltoid muscle. 10. Brachi- 
 alis anticus. 11. Cut extremity 
 of the os humeri. 12. Triceps 
 extensor cubiti. 13. Tendon of 
 the latissimus dorsi. 14. Teres 
 major. 15. Axillary portion of 
 
 the latissimus dorsi. 16. Lower portion of the subscapularis. 17. Origin of 
 the teres major. 18. Lower portion of the scapula. 19. Middle portion of the 
 subscapularis. 
 
 Its tendon is closely connected with that of the latissimus 
 dorsi ; although a small bursa is commonly found between 
 them and near their insertion. A triangular space will be 
 noticed between this muscle and the lower border of the 
 subscapularis, with its base corresponding to the surgical 
 neck of the humerus. 
 
 The circumflex nerve and the posterior circumflex artery will 
 be seen going backwards through this space close to the 
 humerus, while the dorsal branch of the subscapular artery 
 passes through it nearer to the apex. 
 
 The LONG HEAD of the TRICEPS EXTENSOR CUBITI, Fig. 
 96 (12), may be seen at this stage of the dissection, crossing 
 this space vertically behind the teres major. 
 
 The LATISSIMUS DORSI, Fig. 96 (i s), is necessarily exposed 
 in its upper part in the dissection of the axilla, of which it 
 forms, with the teres major, the lower part of the posterior 
 wall of that space. It lies, at first, in this region, on the out- 
 side of the teres major, then below it, and finally anterior to 
 it. It is inserted into the posterior part of the bicipital groove 
 by a thin, broad tendon, which usually extends a little higher 
 up than that of the teres major. 
 
 The student should now review what he has dissected, 
 
DISSECTION OF THE BACK. 223 
 
 should replace the muscles which have been partially de- 
 tached, and get a distinct idea of the boundaries of the axilla, 
 and the relations of the vessels and nerves to these boundaries. 
 This is a most important region, and cannot be too carefully 
 studied with reference to abscesses or tumors occurring in 
 the axilla, fractures of the clavicle, luxations of the head of 
 the humerus, ligation of the axillary artery, &c. The coraco- 
 brachialis and the two heads of the biceps flexor have been 
 exposed, to some extent, but the dissection of these muscles 
 had better be postponed till the arm has been detached from 
 the trunk. 
 
 SECT. II. DISSECTION OF THE BACK. 
 
 The subject should now be turned over, so that the back 
 can be dissected preparatory to removing the upper ex- 
 tremity. It wiir not interfere materially with the dissection 
 of the head and neck, and lower extremities, whenever it is 
 done, as those who are dissecting these parts can attend to 
 the dissection of the back almost as well at one time as ano- 
 ther. When several are dissecting on the same subject, some 
 arrangement should be entered into in the dissection of the 
 back, by which some of the class may be at work while the 
 rest are engaged in reading a description of the parts to be 
 examined. In this way, each member of the class may have 
 the full benefit of the dissection. 
 
 The subject should be placed on the forepart, with the tho- 
 rax elevated, by placing blocks beneath it. The muscles are 
 to be made tense by placing the subject in such a position 
 as will effect this object, which can be readily ascertained 
 by the student himself. It may be necessary to place a small 
 block under the pelvis, or to allow the head to hang over 
 the end of the table. The arms and shoulder are to be so 
 placed as to put the muscles attached to the clavicle, sca- 
 pula, and humerus on the stretch. It is impossible to make 
 a good dissection of the back unless the position of the differ- 
 ent parts concerned is properly attended to. 
 
 The first incision is to be made through the skin and in 
 the median line from the occiput to the lower part of the 
 sacrum. If it be intended to examine the subcutaneous 
 fascia, it is a matter of little consequence in what direction 
 
224 THE UPPEE EXTREMITY. 
 
 the other incisions through the skin are made. To expose 
 the muscles by cutting down on them at once, or by dis- 
 secting off the fascia after the skin has been removed, the 
 incisions should be made in the direction of the fibres of the 
 muscles. There is nothing in particular connected with the 
 subcutaneous fascia on the back which requires notice, ex- 
 cept the cutaneous nerves and vessels ; and even these are 
 not of sufficient practical importance to warrant the student, 
 as a general thing, devoting much time to their dissection. 
 
 The NERVES are derived from the posterior divisions of 
 the spinal nerves. The first cervical gives off, ordinarily, 
 no cutaneous branch. The second sends a large branch to 
 the scalp, which accompanies the occipital artery. The third 
 cervical usually sends also a small cutaneous branch to the 
 back of the head. The rest of the cervical nerves ramify in 
 the integument of the back of the neck. The cervical and 
 dorsal perforate the trapezius, while the six lower dorsal 
 perforate the latissimus dorsi and trapezius to reach the 
 skin. Those below the dorsal perforate the latissimus dorsi. 
 They perforate these muscles near the spinous processes, and 
 for the most part are directed outwards. These nerves are 
 easily traced from the intervertebral foramina, especially 
 when a dissection is made for this purpose. They will be 
 met with from time to time in the dissection of the muscles. 
 
 The ARTERIES are derived from the occipital, the trans- 
 verse humeral, the posterior cervical, the intercostal, and the 
 lumbar. It is not necessary to give any description of these 
 arteries in connection with the fascia of the back. 
 
 Extending from the occipital protuberance to the spinous 
 processes of all the cervical vertebrae, except the atlas, will 
 be found yellow elastic tissue, named the ligamentum nuchce. 
 This is large in some of the lower animals, but in man it is 
 often quite small and indistinct. Some of the muscles of 
 the neck are attached to this ligament. It assists in support- 
 ing the head. 
 
 To dissect the TRAPEZIUS, Fig. 97 (i, 2), an incision may 
 be made through the fascia, or through the skin and fascia at 
 the same time, from the first dorsal vertebra, or near it, trans- 
 versely across to the spine of the scapula. One flap may be 
 dissected upwards and the other downwards until the whole 
 
DISSECTION OF THE BACK. 225 
 
 muscle is exposed. In making this dissection, the student 
 requires no other guide than that afforded by the fibres of 
 the muscle. The direction of these he will see distinctly re- 
 presented in the drawing of the muscles of the back. In 
 the upper part of the neck, this muscle is frequently very 
 small. It arises from the superior ridge on the occipital 
 bone, from the ligamentum nuchae and the spinous processes 
 of the lower cervical and all the dorsal vertebrae ; from this 
 extensive origin the fibres converge and are inserted into the 
 posterior third of the clavicle, the acromion process, and the 
 spine of the scapula. The fibres of the lower part pass ob- 
 liquely upwards, while those of the upper part pass obliquely 
 downwards; the middle fibres have a transverse direction. 
 When the entire muscle acts, it draws the shoulder back- 
 wards. When the upper part acts separately, it may draw 
 the shoulder upwards and backwards ; when the lower part 
 acts separately, it may draw the shoulder downwards and 
 backwards. If the shoulder be fixed, this muscle may draw 
 the head backwards and to one side ; both the trapezii acting 
 at the same time would draw the head directly backwards. 
 That portion of the muscle which arises from the lower 
 cervical and upper dorsal vertebras is aponeurotic for some 
 distance from its origin. The student should be careful not 
 to remove this tendon with the fascia. The lower part of 
 the muscle, where it passes over the spine of the scapula, is 
 also aponeurotic. 
 
 To expose the LATISSIMUS DOESI, Fig. 97 (4), the trape- 
 zius must be detached from the lower dorsal vertebrae and 
 turned upwards. The arm should also be drawn upwards 
 to make its fibres tense. It arises from the spinous processes 
 of the six lower dorsal and all the lumbar vertebras, from the 
 dorsum of the sacrum, the posterior third of the crest of the 
 ilium, and also from the inferior three or four ribs. The 
 fibres pass upwards and forwards, and are inserted by a thin 
 tendon into the bicipital groove of the humerus. The 
 lumbar portion of it is, principally, aponeurotic, and forms 
 the posterior layer of the lumbar fascia. The fleshy slips 
 by which it arises from the ribs indigitate with the heads of 
 the posterior part of the external oblique. 
 
 The upper part of this muscle is much thinner than the 
 lower ; it glides over the inferior angle of the scapula, from 
 
226 
 
 THE UPPER EXTREMITY, 
 Fig. 97. 
 
 THE FIRST AND SECOND AND PART OP THE THIRD LAYERS OP MUSCLES OP THE 
 BACK; THE FIRST LAYER BEING SHOWN UPON THE RIGHT, AND THE SECOND ON THE 
 LEFT SIDE. 1. The trapezius muscle. 2. The tendinous portion which, with a 
 corresponding portion in the opposite muscle, forms the tendinous ellipse on the 
 back of the neck. 3. The acronrion process and spine of the scapula. 4. The 
 latissimus dorsi muscle. 5. The deltoid. 6. The muscles of the dorsum of the 
 scapula, infra-spinatus, teres minor, and teres major. 7. The external oblique 
 muscle. 8. The gluteus medius. 9. The glutei maximi. 10. The levator anguli 
 scapulae. 11. The rhomboideus minor. 12. The rhomboidtjs major. 13. The 
 splenius capitis; the muscle immediately above, and overlaid by the splenius, is 
 the complexus. 14. The splenius colli, only partially seen; the common origin of 
 the splenius is seen attached to the spinous processes below the lower border of 
 the rhomboideus major. 15. The vertebral aponeurosis. 16. The serratus posticus 
 inferior. 17. The supra-spinatus muscle. 18. The infra-spinatus. 19. The teres 
 minor muscle. 20. The teres major. 21. The long head of the triceps, passing be- 
 tween the teres minor and major to the upper arm. 22. The serratus inagnus, pro- 
 ceeding forwards from its origin at the base of the scapula. 23. The internal 
 oblique muscle. 
 
DISSECTION OF THE BACK. 227 
 
 winch a few additional fibres sometimes arise. There is fre- 
 quently a bursa between this part of the scapula and the 
 muscle". It will be observed that the lower part of the 
 muscle is inserted higher up than the upper part, resembling 
 in this respect the pectoralis major. The use of this muscle 
 is to depress the arm and shoulder, and draw the arm to 
 the side of the thorax; it may also rotate the humerus in- 
 wards. When the arm is elevated and fixed, it raises the 
 lower ribs, thus assisting in respiration. 
 
 Between the lower border of the trapezius and the upper 
 margin of the latissimus dorsi, and behind the base of the 
 scapula, is a triangular space, in which the rhomboideus 
 major is seen. 
 
 The trapezius is to be raised by detaching it from its origin, 
 and reflecting it forwards. In doing this, the student must 
 be careful that he does not at the same time raise the rhom- 
 boidei muscles, which are situated immediately beneath the 
 trapezius. 
 
 In raising the latissimus dorsi it is difficult to avoid dis- 
 secting up with it the tendon of the serratus posticus inferior. 
 The connection of the tendon of the latissimus with the fascia 
 lumborum at the posterior border of the external oblique 
 should be observed. 
 
 In raising the trapezius, the spinal accessory nerve, Fig. 63 
 (i s), may be traced ramifying beneath, and sending branches 
 to it. It gets beneath the muscle a short distance above its 
 clavicular attachment. The attachment of the omo-hyoideus 
 to the superior costa of the scapula may be examined at the 
 same time ; also the supra-scapular artery and nerve, as they 
 enter the supra spinata fossa. These were traced to this 
 point while dissecting the supra-clavicular region in the neck. 
 
 The transverse humeral and posterior cervical arteries will 
 be found beneath the trapezius and above the scapula. The 
 first ascends, dividing into branches, which are distributed 
 to the trapezius, levator anguli, scapulas, and splenius mus- 
 cles, and anastomosing with the descending branch of the 
 occipital. The other one passes backwards to near the pos- 
 terior superior angle of the scapula, where it gets beneath 
 the levator anguli scapulae, and descends along the base of 
 the scapula and under the rhomboidei muscles. It supplies 
 the muscles in that region, and anastomoses with the sub- 
 
228 THE UPPER EXTEEMITY. 
 
 scapular. The ramifications of this artery cannot be traced 
 until the rhomboidei and levator anguli scapulas muscles 
 have been dissected. 
 
 It will be recollected, in dissecting off the trapezius and 
 latissimus dorsi, that these muscles are perforated by the cu- 
 taneous nerves of the back. If the student should wish to 
 trace these nerves to their origin, he must dissect them out 
 of the muscles as they are raised. 
 
 The next muscles to be dissected are the rhomboidei major 
 and minor, and the serrati postici superior and inferior. 
 
 The KHOMBOIDEUS MAJOR, Fig. 97 (12), arises from the 
 spinous processes of the superior four or five dorsal ver- 
 tebrae ; its fibres pass transversely across to the base of the 
 scapula, into which they are inserted from the spine to the 
 inferior angle. 
 
 The RHOMBOIDEUS MINOR, Fig. 97 (n), arises from the 
 spinous processes of the inferior two or three cervical verte- 
 brae, and is inserted into that portion of the base of the scapula 
 which corresponds to the spine. The two rhomboidei might 
 be regarded as a single muscle, their separation being often 
 very indistinct. They draw the scapula backwards and some- 
 what upwards; the lower part acting alone will rotate the 
 scapula, so as to depress the acromion process. 
 
 In dissecting oft' the rhomboidei, a little care is necessary 
 not to raise with them the following muscle, which is partially 
 covered by them. 
 
 The SERRATUS POSTICUS SUPERIOR arises from the spinous 
 processes of the lower two or three cervical, and about the 
 same number of the superior dorsal vertebrae ; it is inserted 
 by three fleshy slips into the second, third, and fourth ribs. 
 The action of this muscle is to elevate the ribs into which it 
 is inserted. 
 
 The SERRATUS POSTICUS INFERIOR, Fig. 97 (IG), arises 
 from the spinous processes of the two or three lower dorsal, 
 and upper lumbar vertebrse, and is inserted into the four 
 inferior ribs. Its tendinous origin is closely connected with 
 the latissimus dorsi. Its action is either to depress the lower 
 ribs, and thus assist in expiration, or to fix them, and thus 
 assist the diaphragm, which is an inspiratory muscle. 
 
 Extending from one serratus muscle to the other, is a 
 well-marked aponeurosis ; it is called the vertebral aponeurosis. 
 
DISSECTION OF THE BACK. 229 
 
 Fig. 97 (is). It-is continuous below, with the lumbar fascia, 
 through the inferior serratus and tendon of the latissimus 
 dorsi. If pus be formed beneath the posterior layer of the 
 fascia lumborum, there is nothing to prevent it from travelling 
 "upwards beneath this aponeurosis. 
 
 In dissecting off the serrati and rhomboid ei muscles, the 
 student may notice the nerves which perforate them. 
 
 The principal muscles of the back yet to be examined, 
 have generally a longitudinal direction, and lie more or less 
 parallel to each other. The student should read carefully a 
 description of them before he attempts their dissection. 
 
 The SPLENIUS, Fig. 97 (is), is commonly divided into the 
 splenius colli, and splenius capitis. This division belongs 
 rather to the upper than to the lower part of the muscle. 
 The Splenius Colli arises from the spinous processes of the 
 third, fourth, fifth, and sixth dorsal vertebra. The Splenius 
 Capitis arises from the spinous processes of the inferior cer- 
 vical, and the first and second dorsal vertebra. The former 
 passes upwards, and is inserted by tendinous slips into the 
 transverse processes of the superior two or three cervical 
 vertebras, while the latter also goes upwards, and is inserted 
 into the mastoid process of the temporal bone, where it is 
 overlapped by the insertion of the sterno-cleido-mastoideus, 
 and into the occipital bone below the upper transverse ridge. 
 
 The actions of these two divisions of the splenius are in- 
 dicated by their insertions. The splenius capitis draws the 
 head backwards, and to one side. If the corresponding por- 
 tion of the splenius on the opposite side acts at the same 
 time, they will draw the head directly backwards. The sple- 
 nius colli acts in the same manner on the neck. 
 
 There is a triangular space between the splenii muscles of 
 the two sides in the upper part of the neck, which is filled 
 up with dense areolar tissue, and fat. The comjplexus mus- 
 cles are seen in this space. 
 
 The LEVATOR ANGULI SCAPULAE, Fig. 97 (i o), is situated 
 outside of the splenius. It arises by tendinous slips from the 
 transverse processes of the superior three or four cervical 
 vertebrae. Its fibres pass obliquely downwards and back- 
 wards, and are inserted into the base of the scapula, between 
 the spine and the superior angle. Its origin corresponds 
 nearly with the insertion of the splenius colli. To dissect 
 20 
 
230 THE UPPER EXTREMITY. 
 
 it, the scapula should be depressed and carried forwards. 
 The use of this muscle is to elevate the angle of the scapula, 
 and thus depress the acromion process; acting with the tra- 
 pezius, it assists in raising the shoulder. When the shoulder 
 is fixed, it can bend the head back and to one side. 
 
 When this muscle is detached near its insertion, the student 
 will be able to get a view of the serratus magnus from behind. 
 By moving the scapula in different directions, the attach- 
 ments and relations of this large muscle may be distinctly 
 seen. 
 
 The relations of the levator anguli scapulae to the posterior 
 scalenus should, also, be noticed. It is important to keep in 
 view the relations of the parts which are seen in the dissec- 
 tion of the anterior portion of the neck, to those which are 
 observed from behind. It should be borne in mind that the 
 neck presents a lateral as well as an anterior and posterior view. 
 
 When the splenius is raised from its origin, and turned 
 upwards, the four following muscles are brought into view in 
 the neck. The splenius is perforated near its spinal attach- 
 ment, by several nerves which may be noticed in raising it. 
 
 The COMPLEXUS, Fig. 98 (s), is a large, powerful muscle, 
 with several tendinous intersections. It lies next to the 
 spine, and arises from the transverse processes of the upper 
 three dorsal, and the oblique processes of the four lower cer- 
 vical vertebrae. Its fibres ascend and are inserted into the 
 occipital bone between the two transverse ridges. When 
 one acts alone, it rotates the head, or draws it back and to 
 one side. When both of the complexus muscles act at the 
 same time, they draw the head directly backwards. 
 
 The TRACHELO-MASTOIDEUS, Fig. 98 (7), is a small muscle 
 which arises from the transverse processes of the upper three 
 or four dorsal, and the inferior three or four cervical verte- 
 brae. Its fitres pass upwards, and are inserted into the back 
 part of the mastoid process. The dorsal portion of this 
 muscle is frequently connected to the cervical by a small 
 fasciculus. It assists other muscles in the movements of the 
 head, as drawing it backwards, or backwards and to one 
 side. 
 
 The TRANSVERSALIS COLLI, Fig. 98 (9), is another small 
 muscle, situated on the outside of the preceding. It arises 
 by small slips from the transverse processes of the upper 
 
DISSECTION OF THE BACK. 
 
 231 
 
 Fig. 98. 
 
 five or six dorsal vertebrae, and passes upwards and out- 
 wards, and is inserted into the transverse processes of the 
 lower three or four cervical vertebrae. It assists in turning 
 the neck to one side, or in drawing it backwards. 
 
 The CERVICALIS ASCENDENS, or DESCENDERS, Fig. 98 
 (5), is placed on the outside of the transversalis colli. It 
 arises, by tendinous bands, from 
 the upper four or five ribs, between 
 their angles and tubercles, and 
 passes upwards and outwards, and 
 is inserted into the transverse pro- 
 cesses of the fourth, fifth, and sixth 
 cervical vertebras. The action of 
 this muscle is similar to the last, 
 except that when the neck is fixed, 
 it can assist in elevating the ribs. 
 
 It is not always possible to 
 make a clear dissection of the 
 last three muscles, nor is it very 
 important that the student should 
 spend much time in attempting 
 to do it. They seem to be a 
 sort of a continuation upwards of 
 the sacro-lumbalis and longissimus 
 dorsi. 
 
 At this stage of the dissection, the 
 student will be able to take a gene- 
 ral survey of the posterior spinal 
 nerves in the deeper part of their 
 course, and; also, of the arteries 
 which go to the back. If he has 
 not destroyed the nerves- thus far 
 in the dissection, he can nowvtrace 
 first, the CERVICAL. 
 
 THE FOURTH AND FIFTH, AND PART OF THE SIXTH LAYERS OF THE MUSCLES OF THE 
 
 BACK. 1. The common origin of the erector spinae muscle. 2. The sacro-lumba- 
 lis. 3. The longissimus dorsi. 4. The spinalis dorsi. 5. The cervicalis ascen- 
 dens. 6. The transversalis colli. 7. The trachelo-mastoideus. 8. The complexus. 
 9. The transversalis colli, showing its origin. 10. The semi-spinalis dorsi. 11. 
 The semi-spinalis colli. 12. The rectus posticus minor. 13. The rectus posticus 
 major. 14. The obliquus superior. 15. The obliquus inferior. 16. The multindus 
 spinae. 17. The levatores costarum. 18. Intertransversales. 19. The quadratus 
 lumboruni. 
 
232 THE UPPER EXTREMITY. 
 
 The OCCIPITALIS MAJOR passes through the complexus, 
 beneath which he will find the posterior cervical plexus, which 
 is formed by communicating branches from the upper three 
 cervical nerves. The first cervical or suboccipital, is quite 
 small; it is situated above the obliquus inferior, and the 
 second cervical below it. The third cervical is smaller than the 
 second, and the fourth is smaller than the third. 
 
 The remaining cervical nerves increase in size from above 
 downwards, and require no particular description. They 
 may be traced to the intervertebral foramina as the deep 
 muscles are dissected. 
 
 The POSTERIOR DORSAL NERVES are twelve in number. 
 They divide into external and internal branches. The external 
 branches are found in the areolar interspace between the lon- 
 gissimus dorsi and the sacro-lumbalis. The upper six are 
 expended upon the muscles, while the lower six are distributed 
 to the muscles and integument. The external branches increase, 
 while the internal diminish in size, from above downwards. 
 The lower six become cutaneous, while the upper six are lost 
 in the deep muscles of the spinal fossa. 
 
 The POSTERIOR DIVISIONS of the LUMBAR NERVES have 
 the same general arrangement as the lower dorsal. 
 
 The POSTERIOR SACRAL NERVES are five in number. The 
 upper three divide into external and internal branches. The 
 latter are small and muscular ; the former are quite large, 
 and become cutaneous, receiving a branch from the last 
 lumbar. 
 
 The posterior cervical and transverse humeral arteries are 
 described in the dissection of the neck. 
 
 The OCCIPITAL ARTERY enters the posterior part of the 
 neck beneath the sterno-cleido-mastoideus, passes transversely 
 under the trachelo-mastoideus and splenius, and between the 
 latter and the trapezius becomes subcutaneous, and ascends 
 on the back of the head, Fig. 65 (i 4). In its course it sends 
 small branches to the muscles with which it is in relation. It 
 sends off quite a large branch, named the arteria princeps 
 cervicis, beneath the splenius, which descends on the back of 
 the neck, and anastomoses with branches of the subclavian 
 artery. It also sends a small branch to the dura mater ; this 
 passes through the jugular foramen. 
 
DISSECTION OF THE BACK. 233 
 
 The YERTEBKAL ARTERY sends small branches in its course 
 up the neck, to the deep muscles. 
 
 The deep cervical branch of the subclavian sends branches 
 to the muscles of the back. These anastomose with the 
 occipital and vertebral arteries. 
 
 The INTERCOSTAL ARTERIES send branches to that portion 
 of the back which corresponds to the thorax. These branches 
 supply the muscles as they pass through them to reach the 
 skin. They are named the dorsal branches of the intercostal 
 arteries. 
 
 The LUMBAR ARTERIES send dorsal branches to the muscles 
 and integument in the lumbar region. They correspond to 
 the dorsal branches of the intercostals. The origin and 
 course of these arteries are described elsewhere. 
 
 The SACRO-LUMBALIS, the LONGISSIMUS DORSI, and the 
 SPINALIS DORSI, Fig. 98 (i), may now be dissected. They 
 consist of a single mass in the loins, and cannot be distinctly 
 separated in that region. They constitute the erector spince. 
 They arise in common from the dorsum of the sacrum, the 
 sacro -iliac ligaments, from the spinous, transverse, and oblique 
 processes of the lumbar vertebrae, and from the posterior 
 third of the crest of the ilium. They are covered by a thick, 
 strong tendon, fom which many of their fibres take their 
 origin. At the upper part of the lumbar region these three 
 muscles can be separated from each other. 
 
 The SACRO-LUMBALIS, Fig. 98 (2), is situated on the outer 
 side. It passes upwards, dividing into tendons, which are 
 attached to the ribs at their angles. When this muscle is 
 separated from the longissimus dorsi, and raised from the 
 ribs, six or eight muscular and tendinous slips will be ob- 
 served. These constitute the accessorius ad sacro-lumlalem. 
 They arise from the lower six or eight ribs, and join the ten- 
 dons of the sacro-lumbalis. They vary in number and size. 
 The sacro-lumbalis, besides supporting the spine, can depress 
 the ribs, and thus act as a muscle of expiration. 
 
 The LONGISSIMUS DORSI, Fig. 98 (3), extends upwards on 
 the inner side of the sacro-lurnbalis, and is inserted into all 
 the ribs except the upper two or three, between their angles 
 and tubercles, and also into the transverse processes of the 
 
 20* 
 
234 THE UPPER EXTREMITY. 
 
 dorsal vertebras. It acts on the spine, and also on the ribs, 
 as an expiratory muscle. 
 
 The SPINALIS DORSI, Fig. 98 (4), lies on the inner side of 
 the last muscle, with which it is usually more or less blended. 
 It arises from the spinous processes of the lower two or three 
 dorsal vertebras, and about the same number of lumbar ver- 
 tebrae ; it is inserted into the upper dorsal. 
 
 The QUADRATUS LUMBORUM, Fig. 98 (i 9), should now be 
 dissected, on one side at least, so that the relations of the 
 fascia lumborum may be studied in connection with the mus- 
 cles of the back. It may also be examined with the muscles in 
 the posterior part of the abdominal cavity. It is situated 
 between the erector spines and the cavity of the abdomen. It 
 arises from the posterior part of the crest of the ilium and 
 the ilio-lumbar ligament. The fibres pass upwards, and are 
 inserted into the transverse processes of the upper four lumbar 
 and the last dorsal vertebrae, arid also into the vertebral half 
 of the last rib. An additional set of fibres usually arise from 
 the transverse processes of the lower two or three lumbar 
 vertebrae, pass obliquely upwards, and are inserted into the 
 last rib. The action of this muscle is to depress or fix the 
 last rib, to bend the spine to one side, or to assist in keeping 
 it erect. 
 
 The FASCIA LUMBORUM is attached by three laminae to the 
 vertebral column. The posterior lamina is blended with the 
 tendon of the latissimus dorsi and serratus posticus inferior, 
 and is consequently connected to the spinous processes. The 
 middle layer is attached to the ends of the transverse pro- 
 cesses ; while the anterior layer is attached to the bases of the 
 transverse processes of the lumbar vertebrae, to the lower rib, 
 and to the ligamentum arcuatum. The internal oblique and 
 transversalis muscles are connected to the vertebral column 
 throbgh the medium of this fascia. The space between 
 the middle and anterior laminas is wholly occupied by the 
 quadratus lumborum muscle. If pus should form in this 
 space, it might pass upwards or downwards as far as the 
 attachments of this muscle. If pus should collect in -the 
 space between the middle and posterior layers, it might 
 travel upwards or downwards along the erector spinos 
 which occupies this space. The difference between the 
 
DISSECTION OF THE BACK. 235 
 
 location of a lumbar and psoas abscess will be learned in 
 connection with the psoas fascia. 
 
 The relations of the colon to the muscles and fascia in the 
 lumbar region should be studied. It will be seen that the 
 colon can be reached in this region by simply dividing the 
 three laminae of the fascia lumborum along the external bor- 
 ders of the sacro-lumbalis and quadratus lumborum. The 
 relation of the kidney to the muscles in this region, is also 
 deserving of notice with reference to nephritic abscesses. 
 
 The following muscles may now be exposed, by removing 
 those last dissected : 
 
 The SEMI-SPIN ALIS DOESI and COLLI, Fig. 98 (10, n), 
 might with propriety be considered a single muscle. They 
 present the same arrangement in regard to their origin and 
 insertion, and have a similar function. 
 
 The semi-spinalis colli, arises from the transverse processes 
 of the upper five or six dorsal vertebra?, and passes upwards 
 and is inserted into the spinous processes of the second, third, 
 fourth, and fifth cervical vertebras. 
 
 The semi-spinalis dor si arises from the transverse processes 
 of all the dorsal vertebras below the fifth, excepting the last, 
 and passes upwards and is inserted into the spinous processes 
 of the lower two cervical, and the upper three or four dorsal 
 vertebrae. These muscles co-operate with the erector spinae. 
 
 Situated beneath the two last muscles are a series of small 
 muscles, called, altogether, the MULTIFIDUS SPINAE. They 
 extend between the spinous and transverse processes. The 
 upper one commences at the spinous process of the second 
 cervical vertebra, and is inserted into the transverse process 
 of the third. The last one extends from the spinous process 
 of the last lumbar vertebra to the sacrum. The same muscle 
 may extend over one or two intermediate vertebrae. The 
 action of these is nearly the same as the last. 
 
 The LEVATOEES COSTAEUM, Fig. 98 (i 7), maybe examined 
 at the present time, although they are frequently considered 
 as belonging to the external intercostal muscles. They con- 
 sist of a series of small fan-shaped muscles, which arise from 
 the transverse processes, commencing with the last cervical, 
 and extending to the last dorsal. They pass downwards and 
 outwards, and are inserted into the ribs between their angles 
 and tubercles. They increase in length from above down- 
 
236 THE UPPER EXTREMITY. 
 
 wards. Some of the lower muscles pass in part over the 
 first rib below their origin, to be attached to the next one; 
 these have been called the levatores longiores costarum. 
 
 The INTERS FINALES extend between the spinous processes. 
 Between the dorsal vertebrae they can hardly be said to exist, 
 and are very small in the lumbar region. In the neck, they 
 are found in pairs, corresponding to the bifid condition of 
 the spinous processes. Some of them pass over one or more 
 vertebrae, and are called supra-spinous. There is none be- 
 tween the first two vertebras. 
 
 The INTERTRANS VERSA LES, Fig. 98 (i s), are a series of short 
 muscles, extending between the transverse processes. In the 
 neck, they consist of two fasciculi, an anterior and posterior. 
 In the dorsal region they are generally wanting, excepting 
 between the last two vertebras. In the lumbar region they 
 are smaller than in the neck. They support the spine, and 
 bend it to one side. 
 
 Between the occiput and the upper cervical vertebras are 
 several small muscles, which are worthy of more attention 
 than some of the preceding. 
 
 They are deep-seated, and, to dissect them, the position of 
 the head must be changed, so as to render them tense. 
 
 This group of muscles is separated from the complexus by 
 an aponeurosis and dense areolar tissue. They consist of two 
 obliqui and two recti, on each side; between these will be 
 found a triangular space, occupied by fat and areolar tissue, 
 and containing, also, the posterior division of the suboccipital 
 nerve, which is distributed to those muscles, a plexus of veins, 
 and the vertebral artery. 
 
 The KECTUS CAPITIS POSTICUS MAJOR, Fig. 98 (i s), arises 
 from the spinous process of the second vertebra, passes up- 
 wards, and is inserted into the inferior transverse ridge of 
 the occipital bone. It is of a triangular shape, being broad 
 above and narrow below. It is covered by the complexus, 
 and the superior oblique partly overlaps its insertion. 
 
 The KECTUS CAPITIS POSTICUS MINOR, Fig. 98 (i 2), is a very 
 small muscle, situated beneath the major. It arises from the 
 spinous process of the first cervical vertebra, and is inserted 
 into the occipital bone, between the inferior transverse ridge 
 and the occipital foramen. The small recti muscles are 
 situated nearer to the median line than the large. The recti 
 
DISSECTION OF THE BACK. 237 
 
 muscles draw the head backwards, or to one side. The large 
 recti may assist in rotating it, or moving it on the axis. 
 
 The OBLIQUUS CAPITIS INTERIOR, Fig. 98 (i s), arises from 
 the spinous process of the second vertebra, goes upwards and 
 outwards, and is inserted into the transverse process of the 
 atlas. It moves the atlas round the odontoid process, and 
 thus assists in rotating the head. 
 
 The OBLIQUUS CAPITIS SUPERIOR, Fig. 98 (i 4), arises from 
 the transverse process of the atlas, and passes upwards and 
 inwards, and is inserted into the occipital bone just above the 
 insertion of the rectus major, which is partly covered by it. 
 The upper part of this muscle is broad and aponeurotic. It 
 bends the head backwards and to one side. 
 
 After the muscles on the back of the neck have been dis- 
 sected, the vertebral artery may be examined in its course 
 through the transverse processes, and as it enters the foramen 
 occipitale. It is accompanied by the vertebral vein. 
 
 The great number of muscles on the back, with their nu- 
 merous attachments, renders this part of the body somewhat 
 difficult of dissection and study. Few students have the time 
 and patience to learn all these muscles and their attachments, 
 and, when it is Jone, the knowledge thus acquired cannot 
 long be retained. Yet the dissection of the back should not 
 be neglected ; it should receive a portion of the time and 
 attention of every student. 
 
 Instead of attempting to recollect the exact origin and in- 
 sertion of each muscle, or any mere arbitrary division based 
 upon their arrangement in layers or strata, he should rather 
 endeavor to fix them in his mind according to their individual 
 or combined action. As, for example, he should arrange and 
 classify in his own mind all those muscles which act directly 
 or indirectly on the shoulder, and through the shoulder on 
 the arm or on the walls of the thorax, as in respiration. In 
 this way he will learn what muscles are at fault in displace- 
 ments of the scapula, or in curvatures of the spine depending on 
 a loss of antagonism in the muscles of the two sides, or of tone 
 in those of both sides. All the muscles concerned in support- 
 ing or moving the head should be grouped together as acting 
 in unison, and also those which act on the vertebral column, 
 but not as acting on separate vertebras so much as on its 
 different sections. When the muscles of the back are studied 
 
238 THE UPPER EXTREMITY. 
 
 in this way, classified according to their functions, they become 
 an interesting portion of the animal economy. A knowledge 
 of the exact relations of the muscles of the back to each other 
 is not so important as in many other parts of the body, where 
 there are large vessels and nerves, or other important organs, 
 in relation with them. 
 
 SECT. III. DISSECTION OF THE SHOULDER. 
 
 In detaching the upper extremity from the trunk, it is de- 
 sirable to disarticulate the clavicle from the sternum; but it 
 frequently happens that the dissection of the head and neck 
 is not sufficiently advanced to allow of this, at least on both 
 sides, without injuring those parts. In this case, the clavicle 
 should be left attached to the trunk while the scapula is re- 
 moved with the arm, by separating it at the acromio-clavicu- 
 lar articulation. Even the removal of the scapula will inter- 
 fere more or less with the lower part of the side of the neck, 
 but not materially, if the back of the neck has been fully 
 dissected. The vessels and nerves in the axilla should be 
 tied together, so that they can be made tense by fastening 
 them to something with hooks or twine. 
 
 In dissecting the arm, no specific rules can be laid down in 
 regard to the position. The student must select such position 
 as will put the muscle or muscles which he is dissecting on 
 the stretch, or allow him to trace with the greatest facility the 
 vessels and nerves as he proceeds in his dissection. 
 
 The anterior part of the DELTOID was, Fig. 90 (s), exposed 
 with the clavicular portion of the pectoralis major ; the re- 
 mainder of it, Fig. 100 (i s), may now be dissected by con- 
 tinuing the dissection from before backwards. The skin 
 may be raised first, so as to examine the deltoid fascia and 
 to trace the supra-acromial branches, Fig. 103 (i), from the 
 cervical plexus of nerves, and cutaneous branches (2) from 
 the circumflex nerve which is reflected over the posterior 
 margin of the muscle; or the student may remove the skin 
 and fascia from the muscle at the same time. This muscle 
 is composed of very large fasciculi, each one of which seems 
 to be a small muscle of itself. 
 
 It arises, tendinous and fleshy, from the outer third of the 
 clavicle, from the acromion process and spine of the scapula; 
 
DISSECTION OF THE SHOULDER. 
 
 239 
 
 Fig. 99. 
 
 its fibres converge to form a short, thick tendon, which is 
 inserted into the deltoid ridge of the humerus. This muscle 
 may be divided into anterior, middle, 
 and. posterior portions. It will be seen, 
 from the origin and insertion of the 
 deltoid, that it is of a triangular form, 
 and covers all the outer part of the 
 shoulder-joint. Its action is to raise 
 the arm, and to keep the head of the 
 humerus applied to the glenoid cavity. 
 If the posterior fibres act alone, they 
 will draw the arm upwards and back- 
 wards, while the anterior fibres, acting 
 alone, will draw it upwards and for- 
 wards. Its origin corresponds to the 
 insertion of the trapezius. 
 
 This muscle should be raised by 
 detaching it from its origin and re- 
 flecting it downwards. In dissecting 
 it up from the humerus, the anterior 
 and posterior circumflex arteries and the 
 circumflex nerve Tll be observed enter- 
 ing its under surface It will be seen of the ^ 6> Middle of 
 
 that a blow Over the deltoid might, by the deltoid, showing the fasci- 
 
 injuring the circumflex nerve, paralyze plated character of its fibres. 
 
 3 , m , . , ,. J i 7. Its insertion. 8. Shaft of 
 
 this muscle. There is also to be noticed the os humeri. 
 a large lursa between it and the upper 
 
 and outer part of the humerus. Its relations to the shoulder- 
 joint and the parts around it are deserving of special atten- 
 tion. It will be observed that its under surface is more 
 tendinous than the outer, and that many of the muscular fas- 
 ciculi terminate in a- tendinous structure some distance from 
 the point of insertion. 
 
 The deltoid muscle is to be preserved, in order to replace 
 it after the parts which are covered by it have been dissected. 
 It is only in this way that its relations can be properly un- 
 derstood. 
 
 The SUPRA-SEINATUS, Fig. 100 (2), occupies the supra-spi- 
 nata fossa. It is covered by the trapezius, and by a thick, 
 dense aponeurosis, named the supra-spinous fascia. This fascia 
 is attached to the margins of the fossa, and sends a process for- 
 
 A VIEW OP THE DELTOID 
 MUSCLE. 1. Clavicle. 2,3, 
 4. Origin of the deltoid from 
 the clavicle, acromion, and 
 spine of the scapula. 5. Body 
 
240 THE UPPEE EXTREMITY. k 
 
 wards, to be lost in the tendon of the supra-spinatus muscle. 
 Eemoving this fascia, the muscle will be exposed. It arises 
 from the surface of the whole fossa, except the anterior part, 
 and also from the under surface of the fascia, posteriorly. It 
 passes beneath the acromion process, and ends in a tendon 
 which is inserted into the upper part of the great tuberosity 
 of the humerus. 
 
 Its tendon is blended with the capsular ligament of the 
 joint, over which it passes. There is a great deal of loose 
 areolar tissue situated around this muscle, where it passes 
 under the acromion process and the coraco-acromial ligament. 
 It assists the deltoid in raising the arm, and, when it is raised, 
 prevents the head of the humerus from being displaced into 
 
 Fig. 100. 
 
 A POSTERIOR VIEW OF THE MUSCLES OF THE SHOULDER, WITH THE DELTOID. 
 1. Acromion scapulae. 2. Supra-spinatus muscle. 3. Spine of the scapula. 4. 
 Posterior portion of the origin of the deltoid. 5. Infra-spinatus muscle. 6. Teres 
 major. 7. Teres minor. 8. Long head of the triceps extensor. 9. Its second head. 
 10. The shaft of the os humeri. 11. Brachialis anticus. 12. Insertion of the 
 deltoid. 13. Its middle portion forming the round part of the shoulder. 
 
 the axilla, by keeping it firmly applied to the glenoid cavity ; 
 it also draws the capsular ligament from beneath the acromion 
 process, when the head of the humerus is pressed against it. 
 In raising the supra-spinatus, the supra-scapular artery and 
 nerve are to be traced. They are continued into the infra- 
 spinata fossa by passing under the acromion process, where 
 they will be met with when the infra-spinatus muscle is dis- 
 sected. The nerve usually passes through the coracoid notch, 
 to enter the supra-spinata fossa, while the artery generally 
 passes over the ligament which subtends this notch and con- 
 
DISSECTION OF THE SHOULDER. 241 
 
 verts it into a foramen. The ligament is named the coracoid 
 or supra-scapular ligament. 
 
 The two following muscles are situated on the dorsum of 
 the scapula, below the spine : the infra-spinatus, and teres 
 minor. Besides the skin and subcutaneous fascia, they are 
 covered with the infra-spinous fascia, or aponeurosis. This 
 fascia is attached to the margins of the infra-spinata fossa, 
 and, at the posterior border of the deltoid, divides into two 
 layers, one of which is continuous with the deltoid fascia over 
 that muscle, while the other passes beneath it, and becomes 
 continuous with the brachial fascia. 
 
 The INFKA-SPINATUS MUSCLE, Fig. 101 (s, is), arises from 
 nearly the whole of the infra-spinata fossa, and posteriorly 
 
 A POSTERIOR VIEW OF THE MUSCLES OF THE SHOULDER WHICH STRENGTHEN THE 
 ARTICULATION. 1. Acromion scapulae. 2. Supra-spinatus muscle. 3. Upper angle 
 of the scapula. 4. Spine of the scapula. 5. Origin of the infra-spinatus muscle. 
 6, 7. Origin of the teres major. 8. Origin of the teres minor. 9. Insertion of the 
 teres major. 10. Shaft of the os humeri. 11. Lower part of the capsular ligament. 
 12. Insertion of the teres minor. 13. Insertion of the infra-spinatus. 
 
 from the infra-spinous fascia. The fibres which arise from 
 the spine of the scapula overlap those below, and they all 
 converge to form a short tendon, which is inserted into the 
 great tuberosity of the humerus, just below the insertion of 
 the supra-spinatus, with which it is connected. Its tendon is 
 blended with the capsular ligament. It can assist the deltoid' 
 in raising the arm, and drawing it backwards ; or it can rotate 
 the humerus outwards; it may also withdraw the capsular 
 ligament from the joint, or, when the arm is raised, depress 
 the head of the humerus. 
 21 
 
242 THE UPPER EXTREMITY. 
 
 The TERES MINOR, Fig. 101 (s, 1 2), is quite a small muscle, 
 and might be regarded as a part of the infra-spinatus. It 
 arises from a depression on the dorsum of the scapula, near 
 the inferior border, commencing about an inch from the pos- 
 terior inferior angle, and from the infra-spinous fascia. It is 
 inserted into the great tuberosity of the humerus, just below 
 the insertion of the infra-spinatus. Its action is the same as 
 that of the preceding muscle, with which it is sometimes in- 
 separably connected. 
 
 The TERES MAJOR, Fig. 101 (9), was exposed, from before, 
 in the dissection of the axilla ; it may now be examined from 
 behind. It arises from a rough surface on the dorsum of the 
 scapula, near the inferior angle, and from the fascia covering 
 it. Its direction, insertion, and relations to the latissimus 
 dorsi, have been noticed. 
 
 The long head of the TRICEPS EXTENSOR CUBITI, Fig. 100 
 (s), is necessarily brought into view in dissecting the teres 
 major. It may be noticed at the present time as one of the 
 muscles connected to the scapula, and as forming a part of 
 the anatomy of the region now being examined. In raising 
 the infra-spinatus and teres minor, the supra-scapular artery 
 and nerve are to be traced from beneath the acromion process. 
 The dorsal branch of the subscapular artery, by passing over 
 the inferior border of the scapula and beneath the teres minor, 
 also enters this fossa. These arteries anastomose freely with 
 each other, and also with the transverse humeral, along the 
 base of the scapula. Articular branches to the shoulder-joint, 
 are derived from both the supra-scapular artery and nerve. 
 
 The student should now review the parts which have been 
 dissected about the shoulder. The muscles which have been 
 raised should be replaced and their relations and functions 
 carefully noted without the aid of a book. It will be observed 
 that the deltoid, when placed in situ, covers the following 
 parts : The outer portion of the shoulder-joint, and the upper 
 part of the humerus, including its two tuberosities ; the bi- 
 cipital groove, containing the long head of the biceps, and 
 anterior to this the coracoid process, and, to some extent, the 
 muscles attached to it; and posteriorly the infra-spiriatus, 
 and teres, minor and major, near their insertions. 
 
 He is now prepared to understand the position of the head 
 
DISSECTION OF THE SHOULDER. 
 
 243 
 
 of the humerus when luxated either backwards, downwards, 
 or forwards, and the new relations it acquires in these dis- 
 placements to the surrounding parts. He can readily see for 
 himself what muscles will be relaxed, and what will be put 
 on the stretch when the head of the humerus is made, by 
 displacement, to occupy a new position. He can now note 
 the effect of the contraction of the deltoid in producing dis- 
 placement of the acromion process when broken off, or that 
 of the trapezius in preventing displacement ; also the effect 
 of the contraction of the muscles attached to the coracoid 
 process when that is fractured. These practical points should 
 be impressed on the mind while the parts involved are before 
 him. 
 
 The shoulder-joint and ligaments around it may now be 
 examined. This can be done 
 without interfering with any- Fig. 102. 
 
 thing yet to be dissected on the 
 arm. 
 
 The clavicle and acromion pro- 
 cess are connected by ligament- 
 ous fibres which surround the 
 articulation, forming a sort of 
 fibrous capsule. As the fibres 
 are more numerous above and 
 below the joint, they are some- 
 times spoken of as the SUPERIOR 
 and INFERIOR ACROMIO-CLAVIC- 
 ULAR LIGAMENTS, Fig. 102 (i). 
 This joint sometimes Contains 
 two synovial membranes which 
 are separated by an interarticular 
 fibro-cartilage. This fibro-carti- 
 laginous septum, however, is 
 sometimes imperfect, when there 
 will be only one synovial mem- 
 brane in the joint. The articular 
 surfaces of this joint are very 
 small, rendering it difficult to 
 keep the acromial extremity of 
 the clavicle in its proper place 
 after it has been luxated. 
 
 THE LIGAMENTS OF THE SCAPULA 
 AND SHOULDER-JOINT. 1. The su- 
 perior acroinio-clavicular ligament. 
 2. The coraco-clavicular ligament; 
 this aspect of the ligament is named 
 trapezoid. 3. The coraeo-acromial 
 ligament. 4. The coracoid ligament. 
 5. The capsular ligament. 6. The 
 coraco-humeral ligament. 7. The 
 long tendon of the biceps issuing 
 from the capsular ligament, and 
 entering the bicipital groove. 
 
244 THE UPPER EXTREMITY. 
 
 The clavicle is connected to the coracoid process by two 
 Kgamentous fasciculi; the posterior and internal is named 
 the CONOID, and the anterior the TRAPEZOID LIGAMENT. 
 They form really but a single ligament, the coraco-clavicular, 
 Fig. 102 (2). They extend from the coracoid process to a 
 rough protuberance on the under surface of the clavicle, and 
 about an inch from its acromial extremity. In front they 
 are separated by a space which is filled up with areolar tissue, 
 but posteriorly they appear as a single ligament. 
 
 Sometimes quite a perfect joint is found between the cora- 
 coid process and the clavicle which allows the latter to move 
 on the former. 
 
 The CORACOID LIGAMENT, Fig. 102 (4), subtends the coracoid 
 notch, converting it into a foramen. 
 
 The TRIANGULAR, or CORACO-ACROMIAL LIGAMENT, Fig. 
 103 (3), extends from the coracoid process to the acromion. 
 Its coracoid attachment is much broader than the acromial. 
 It fills up, in part, the notch between these processes and pre- 
 vents the head of the humerus from being forced upwards 
 between them. 
 
 The CORACO-HUMERAL LIGAMENT, Fig. 102 (e), extends 
 from the coracoid process to the great*"tuberosity of the 
 humerus. It may be considered as a part of the capsular 
 ligament. 
 
 The CAPSULAR LIGAMENT, Fig. 102 (5), of the shoulder- 
 joint is attached above to the neck of the scapula, and below 
 to the anatomical neck of the humerus. Its length allows the 
 head of -the humerus to be separated a short distance from the 
 scapula. Its strength is greatly increased by its connection 
 with the tendons of the supra-spinatus, infra-spinatus, teres 
 minor, and subscapularis muscles. These tendons, however, 
 do not add to the strength of the lower part of the ligament, 
 and hence there is a predisposition to luxation of the head of 
 the humerus downwards. 
 
 When the capsule is partly divided, the tendon of the long 
 head of the biceps flexor cubiti, Fig. 102 (7), will be seen 
 passing over the upper part of the articular cavity. It is 
 inside of the ligament, but external to the synovial mem- 
 brane, which is reflected around it and prolonged an inch or 
 more downwards in the bicipital groove, forming a pouch, 
 
\ 
 DISSECTION OF THE ARM. 245 
 
 which communicates with the cavity of the joint. The ex- 
 tent of the synovial membrane is worthy of notice, as it is 
 reflected over the head of the humerus, the internal surface 
 of the capsular ligament, including a portion of each of the 
 tendons connected with it, and the glenoid cavity. While it 
 frequently communicates with the bursae beneath the tendons 
 of the infra-spinatus and subscapularis. 
 
 The GLENOID LIGAMENT surrounds the margin of the glen- 
 oid cavity, and deepens and increases the extent of its ar- 
 ticulating surface. In structure it is fibre-cartilaginous, the 
 cartilage predominating where it is attached to the bone and 
 connected with the articular cartilage. The tendon of the 
 long head of the biceps appears to arise, by two fasciculi, 
 from the upper part of this ligament. 
 
 SECT. IY. DISSECTION OF THE AKM. 
 
 Having finished the examination of the shoulder, the next 
 stage in the dissection will embrace the arm and a part of the 
 forearm. An incision may be made through the skin along 
 the forepart of the arm, and in front of the elbow-joint, ex- 
 tending it down four or five inches on the forearm. There 
 is no necessity for making any transverse incision in the skin 
 at present ; if it be done, however, care must be taken not to 
 cut the cutaneous vessels and nerves. 
 
 After reflecting the skin from the anterior part of the arm 
 and bend of the arm, the following vessels and nerves are to* 
 be traced in the superficial fascia, or subcutaneous areolar 
 tissue. As they have been, for the most part, already exposed 
 in the axilla, the student will have no difficulty in following 
 them : 
 
 The CEPHALIC VEIN, Fig. 94 (10), will be found passing 
 down the outer side of the arm. Just above the bend it re- 
 ceives a large branch, the MEDIAN CEPHALIC, Fig. 94 (is), 
 which joins it on its ulnar side. The cephalic now becomes 
 the radial, and may be traced as far as the skin has been 
 raised, taking care not to destroy filaments of the external 
 cutaneous nerve, which has now become subcutaneous. The 
 MEDIAN CEPHALIC may also be traced to its commencement 
 in the median vein. 
 
 21* 
 
246 THE UPPER EXTREMITY. 
 
 The BASILIC VEIN, Fig. 94 (4), will be found passing down 
 the inner part of the arm. It is much larger than the 
 cephalic; near the bend of the arm it receives the MEDIAN 
 BASILIC, Fig. 96 (5), which joins it from the radial side. The 
 basilic now becomes the ulnar vein, and is to be traced down 
 as far as the cephalic was dissected. The median basilic is 
 to be followed to its termination in the median vein, which 
 may now be exposed for two or three inches, 
 
 The MEDIAN VEIN, Fig. 94 (4), will be seen, bifurcating 
 to form the median basilic and the median cephalic. The 
 median vein., near its bifurcation, gives off a short trunk, 
 which dips down to join the deep veins ; this is named the 
 VENA COMMUNICANS, Fig. 94 (5). 
 
 The internal cutaneous, the lesser internal cutaneous, and 
 the intercosto-humeral nerves, should be dissected with the 
 basilic vein. These nerves are easily followed by making 
 them slightly tense, when their course will readily be seen 
 under the fascia. 
 
 The INTERNAL CUTANEOUS NERVE, Fig. 103 (e, 7), in the 
 lower part of the arm, divides into an external and internal 
 branch. The external division passes over the median basilic 
 vein, and descends on the front of the forearm; while the 
 internal passes over the inner part of the elbow, and winds 
 round to the back part of the forearm. 
 
 The LESSER INTERNAL CUTANEOUS, Fig. 103 (9), descends 
 on the inner aspect of the arm to the space between the in- 
 ternal condyle and the olecranon process, sending off fila- 
 ments in. its course to the skin on the posterior part of the 
 arm, aitfi for a short distance below the elbow. Near the 
 elbow, it gives off a filament to anastomose with the internal 
 cutaneous. The intercosto-humeral, Fig. 103 (i o), is lost in the 
 skin on the upper and back part of the arm. 
 
 On the outside of the arm are usually two cutaneous 
 branches, Fig. 103 (3) and Fig. 104 (5) from the musculo-spiral 
 nerve. One of these generally accompanies the cephalic vein 
 to the bend of the arm ; the other descends more externally, 
 and, passing over the elbow-joint, supplies filaments to the 
 skin on the back and upper part of the forearm. 
 
 The EXTERNAL or MUSCULO-CUTANEOUS, Fig. 103 (4), be- 
 comes superficial just above the bend of the arm, and outside 
 of the tendon of the biceps flexor muscle. A large branch 
 
DISSECTION OF THE AKM. 
 
 247 
 
 generally passes behind the median cephalic vein, which may 
 be used as a guide for finding it. 
 
 Fig. 103. Fig. 104. 
 
 PLAN OF THE CUTANEOUS NERVES ON 
 
 THE FKONT OF THE ARM. 1. Supra-da- 
 
 vicular nerves. 2. Branches of the cir- 
 cumflex nerve. 3. External cutaneous 
 (upper branch) of the museulo-spiral 
 nerve. 4. Musculo-cutaneous. 5. Branch 
 of ulnar nerve. 6. Internal cutaneous : 
 external branch. 7. Inner branch of 
 that nerve. 8. Offset to the upper arm 
 from same. 9. Lesser internal cutane- 
 ous. 10. Intercosto-humeral nerve. 
 
 PLAN OF THE CUTANEOUS NERVES OF 
 THE BACK OF THE AllM AND FOREARM. 
 1. Supra-acroinial branches of the 
 cervical plexus. 2. Cutaneous branches 
 of the circumflex nerve. 3. Internal 
 cutaneous of the museulo-spiral. 4. 
 Intercosto-humeral branches. 5. Ex- 
 ternal cutaneous (inferior) of the mus- 
 eulo-spiral. 6. Ending of the nerve of 
 Wrisberg. 7. Part of the internal cuta- 
 neous for the back of the forearm. 8. 
 Offset from the dorsal branch of the 
 ulnar nerve. 9. Radial nerve. 10. 
 Branch of the musculo-cutaneous for the 
 back of the forearm. 
 
 The arrangements of the veins in the bend of the arm vary 
 so much, that it is impossible to give a description which 
 

 248 
 
 THE UPPER EXTREMITY. 
 
 will apply to any considerable number of cases. The two 
 median veins particularly, are very irregular. The cutane- 
 
 Fig. 105. 
 
 1. The radial vein. 2. The cephalic vein. 3. The 
 anterior ulnar vein. 4. The posterior ulnar vein. 
 5. The common ulnar vein. 6. The basilic vein. 7. 
 The point at which the basilic vein pierces the fascia. 
 8. The median vein. 9. The communication between 
 the deep veins of the forearm and the median. 10. 
 The median cephalic vein. 11. The median basilic 
 vein. 12. A slight convexity of the deep fascia, formed 
 by the brachial artery. 13. The slip of fascia derived 
 from the tendon of the biceps, which separates the 
 median basilic vein from the brachial artery. 14. 
 The external cutaneous nerve, piercing the fascia, 
 and dividing into two branches, which pass behind 
 the median cephalic vein. 15. The internal cutane- 
 ous nerve, dividing into branches, which pass in 
 front of the median basilic vein. 16. The nerve of 
 Wrisberg. 17. The spiral cutaneous nerve, branch 
 of the musculo-spiral nerve. 
 
 ous nerves, on the contrary, usually have nearly the same 
 position ; so that they may be avoided by selecting a proper 
 place for opening a vein. The place selected is more import- 
 ant to be considered in bleeding than any particular vein. 
 
 As the internal cutaneous nerve is more superficial, usually 
 passing in front, Fig. 105 (12), of the median basilic, than the 
 external cutaneous, which is commonly situated behind the 
 median cephalic, Fig. 105 (14), the outer part of the bend of 
 the arm should be selected for opening a vein. The lymph- 
 atics, also, are less numerous here than in the middle or inner 
 part of this region, and are not so liable to be wounded. The 
 relations of the veins in the bend of the arm to the median 
 nerve and brachial artery, will be observed at another time. 
 
 The YENA COMMUNICANS, Fig. 99 (is) and Fig. 105 (9), 
 may now be examined ; so that the superficial fascia can be 
 divided and reflected laterally from the median line in the 
 same manner as the skin. This is a short vein, which 
 
DISSECTION OF THE AEM. 
 
 249 
 
 establishes a direct communication F5 S- 10G - 
 
 between the superficial and deep- 
 
 seated veins. It has no valves ; and 
 
 hence, in varicose aneurism, or aneu- 
 
 risrnal varix, it allows the blood to 
 
 pass readily from one set of veins to 
 
 the other. 
 
 The SUPEKFICIAL LYMPHATICS 
 accompany the veins, especially the 
 basilic. A single lymphatic gland 
 is placed in front of the inner con- 
 dyle. The lymphatics terminate in 
 the axillary glands. 
 
 The DEEP FASCIA, or BKACHIAL 
 APONEUEOSIS, Fig. 106, lies directly 
 beneath the superficial fascia. It 
 consists of fibres, running, some in a 
 longitudinal, some in a spiral, and 
 others in a circular direction. It 
 increases in thickness and strength 
 from above downwards. Above, it 
 is connected to the pectoral, deltoid, 
 infra-spinous, and axillary fasciae, also 
 to the tendons of several of the mus- 
 cles about the shoulder; some of 
 which are capable of rendering it 
 more or less tense when they con- 
 tract. It is connected to the humerus 
 by two processes, or septa, an exter- 
 nal and an internal. 
 
 The external is attached to the 
 outer part of the humerus, extending 
 from the outside of the deltoid ridge 
 to the external condyle, separating the 
 triceps extensor from the brachialis 
 anticus muscle, and, at the same 
 time, giving origin to many fibres 
 of these muscles, especially at the 
 
 A VIEW OP THE FASCIA BRACHIALIS IN ITS WHOLE EXTENT. 1. Portion covering 
 the deltoid muscle. 2. Portion covering the upper part of the biceps. 3. Portion 
 
 covering the coraco-brachialis. 4. Portion covering the lower part of the biceps. 
 
 don of the biceps. 6. Op 
 by the expansion from the tendon of the bicepp. 8. Fascia over the flexor sublimis. 
 
 5. Tendon of the biceps. 6. Opening for the vein. 7. Aponeurosis as strengthened 
 by the expansion from the tendon of the bicepp. 8. Fascia over the flexor sublimis 
 9. Fascia over the flexor carpi radialis. 10. Commencement of the palmar fascia. 
 
250 
 
 THE UPPER EXTREMITY. 
 
 lower part of the arm. The mnsculo-spiral nerve and supe- 
 rior profunda artery perforate this intermuscular septum. 
 
 The internal septum commences at the insertion of the teres 
 major and latissimus dorsi, and extends to the inner condyle 
 of the humerus. It is narrower above than below. The 
 brachialis anticus and triceps extensor 
 Fig. 107. cubiti muscles are intimately connected 
 
 with it in the lower part of the arm. It 
 is perforated by the ulnar nerve. 
 
 The brachial aponeurosis furnishes 
 sheaths for the muscles of the arm, and 
 is connected to the sheaths of the bra- 
 chial vessels and nerves. Besides its 
 attachment to prominent points about 
 the elbow, it is continued into the apo- 
 neurosis of the forearm. It binds down 
 the muscles of the arm, gives attachment 
 to muscular fibres, and serves to protect 
 the brachial vessels and nerves. 
 
 The BICEPS FLEXOR CUBITI MUSCLE, 
 Fig. 107 (i s), may now be exposed by 
 dividing the aponeurosis along the mid- 
 dle of the forepart of the arm, and re- 
 flecting it to each side. The heads of 
 this muscle arise, as has been seen, the 
 long one from the upper part of the 
 glenoid cavity, and the short from 
 the coracoid process, in common with 
 the coraco-brachialis, from which it 
 cannot be separated without making 
 an arbitrary division. The heads unite 
 just above the middle of the humerus, 
 to form quite a large, prominent belly, 
 which ends in a flat tendon, a short dis- 
 
 A VIEW OP THE MUSCLES ON THE FRONT OP THE ABM. 1. Clavicle. 2. Coracoid 
 process and origin of the short head of the biceps. 3. Acromion scapulae. 4. Head 
 of the os humeri. 5. Tendon of the biceps muscle in the bicipital groove. 6. Co- 
 raco-humeral dissected off. 7. Cut portion of the pectoralis major. 8. Long 
 head of the biceps. 9. Insertion of the deltoid. 10. Cut portion of the tendinous 
 insertion of the pectoralis minor. 11. Coraco-brachialis. 12. Short head of the 
 biceps. 13. Latissimus dorsi. 14. Inner portion of the triceps. 15. Body of the 
 biceps. 16. Outer portion of the triceps. 17. Brachialis anticus. 18. Origin of 
 the flexor muscles. 19. Brachialis anticus nea.r its insertion. 20. Tendon of the 
 biceps. 21. Fasciculus from the biceps tendon to the brachial aponeurosis. 22. 
 Flexor carpi radialis. 23. Palmaris longus. 24. Supinator radii longus. 
 
DISSECTION OF THE AKM. 
 
 251 
 
 Fig. 108. 
 
 tance above the elbow-joint. The short head is muscular from 
 near its origin ; while the long one continues tendinous to 
 near their junction. The latter 
 is bound down in the bicipital 
 groove by transverse fibres, 
 which are said to be torn some- 
 times, allowing a displacement 
 of this tendon. The biceps 
 is inserted into the tubercle of 
 the radius. 
 
 From its tendon proceeds 
 an aponeurotic .expansion, 
 Fig. 107 (21), which passes in- 
 wards and downwards across 
 the elbow-joint, and joins the 
 aponeurosis of the forearm, 
 which, by means of this con- 
 nection, is made tense by the 
 contraction of the biceps mus- 
 cle. This fibrous expansion 
 is liable to be wounded in 
 bleeding at the 'foend of the 
 arm, which may be followed 
 by lameness in the limb for a 
 few days. 
 
 This muscle flexes the fore- 
 arm on the arm, and renders 
 its aponeurosis tense. It can 
 also rotate the radius out- 
 wards, and assist in abduct- 
 ing the arm, as it is attached 
 above the shoulder-joint. The 
 action of the biceps on the 
 upper part of the radius, 
 when a fracture occurs just 
 below the tubercle, is to ro- 
 tate the upper fragment out- 
 wards, and draw it upwards, 
 
 A PLAN OP THE NERVES OF THE ARM. A. Axillary artery, u. Brachial artery. 
 Nerves: 2. Supra-scapular. 3. Subscapular. 4. Internal cutaneous. 5. Musculo- 
 cutaneous. 6. Circumflex. 7. Ulnar. 8. Superficial branch of the same to the 
 hand. 12. Median. 13. Anterior interosseous. 15. Musculo-spiral. 16. Radial. 
 17. Posterior interosseous. 
 
252 THE UPPER EXTREMITY. 
 
 as in flexion of the forearm. The dissection of the deep part 
 of the tendon of the biceps may be postponed until the vessels 
 in this region have been examined. 
 
 The CORACO-BRACHIALIS, Fig. 107 (i i), may next be dis- 
 sected. It arises from the coracoid process, and extends 
 obliquely downwards to the middle third of the humerus 
 into the inner part of which it is inserted, between the brachi- 
 alis anticus and deltoid in front, and the triceps extensor 
 behind. In dissecting this muscle, the student must be care- 
 ful not to cut the external cutaneous nerve, which commonly 
 passes obliquely through it from above downwards and out- 
 wards. The coraco-brachialis elevates and draws the arm 
 forwards, and in front of the thorax ; it can also rotate it 
 outwards. When the arm and forearm are fixed, both this 
 and the biceps can act on the scapula. 
 
 The arteries which supply the biceps and coraco-brachialis 
 muscles, are branches from the axillary and brachial ; they 
 do not require any particular description. 
 
 The nerves are derived principally from the external cuta- 
 neous. Before raising the biceps and coraco-brachialis, it 
 will be proper to proceed with the dissection of the brachial 
 vessels and nerves. 
 
 The brachial artery, vence, comites, and median nerve, should 
 be dissected down the arm together. The nerve will be found 
 at first, lying in front and a little to the outside of the artery, 
 near to the coraco-brachialis muscle, but gradually, as it de- 
 scends, getting to the inside of it. The external cutaneous 
 nerve sometimes comes from the median, instead of the bra- 
 chial plexus, and, not unfrequently, a branch is given oft* from 
 the median, which joins the external cutaneous beneath the 
 biceps. The median nerve is sometimes found behind the 
 brachial artery. 
 
 The BRACHIAL ARTERY, Fig. 92 (i o), is a continuation of 
 the axillary. It extends from the lower borders of the ten- 
 dons inserted into the bicipital groove to the bend of the 
 arm, where it divides into the radial and ulnar. It is not 
 covered by any muscle throughout its whole course, unless 
 it is overlapped by the belly of the biceps, when that muscle 
 is unusually developed. It is in relation on the outside 
 with the coraco-brachialis above, and the biceps lower down. 
 Behind, it is in relation above with the tendons of the teres 
 
DISSECTION OF THE AEM. 253 
 
 major and latissimus dorsi, the triceps extensor, and the co- 
 raco-brachialis ; below these it rests on the brachialis anticus. 
 In the upper part of the arm it is placed on the inner side 
 of the humerus, but is in front of the bone, where it rests 
 on the brachialis anticus. 
 
 At the bend of the arm it is situated beneath the aponeu- 
 rotic expansion from the tendon of the biceps muscle, which 
 protects it to some extent when the median basilic vein is 
 opened in bleeding. To ascertain the exact position of it, 
 before opening the vein the biceps should be relaxed, other- 
 wise the tension of this aponeurosis might prevent the pulsa- 
 tion of the artery, being felt. The median nerve here lies on 
 the inner side of the artery. 
 
 Usually there is no necessity for opening a vein over 
 either the artery or nerve, and hence the liability of wound- 
 ing either of them may be avoided. The anomalies which 
 occur in the brachial artery are interesting in a surgical 
 point of view ; but they vary so much, that a description of 
 them must be omitted. It may be mentioned, however, that 
 the one most commonly met with is a high division of the 
 artery into the radial and ulnar, which may occur at any 
 point in the arltn, even as high as the axilla. It gives off the 
 four following branches : 
 
 The superior profunda, Fig. 92 (is), arises just below the 
 tendon of the teres major, and passes obliquely downwards 
 and backwards to enter the fissure between the two heads of 
 the triceps which arise from the humerus ; it accompanies 
 the musculo-spiral nerve. Sometimes this branch arises in 
 common with the posterior circumflex, or with the inferior 
 profunda. 
 
 The inferior profunda, Fig. 92 (i e), arises lower down, and 
 proceeds obliquely downwards to the inner part of the elbow- 
 joint, accompanying in the latter part of its course the ulnar 
 nerve. 
 
 The nutritious branch is given off near the middle of the 
 humerus, which it penetrates through the nutritious foramen. 
 
 The anastomotic branch, Fig. 92 (17), arises usually about 
 two inches above the bifurcation into the radial and ulnar, 
 and goes to the inner part of the elbow. These branches, 
 except the nutritious, will be noticed again in connection 
 with the vascular anastomosis around the elbow-joint. 
 22 
 
254 THE UPPER EXTREMITY. 
 
 The VENJE COMITES consist of two veins, one on each side 
 of the artery; they communicate frequently with each other 
 across it. Sometimes there is found a collateral vein open- 
 ing into the venae comites, both in the upper and lower part 
 of the arm. These veins are to be cut away in dissecting the 
 artery. 
 
 The ULNAR NERVE, Fig. 93 (3), passes down, at first, close 
 to the inner side of the artery, but gradually diverges from 
 it as it proceeds towards the notch, between the inner con- 
 dyle and the olecranon process, through which it goes to the 
 forearm. It gives off no branches in the arm. It is ac- 
 companied in the lower part of its course, as before men- 
 tioned, by the inferior profunda artery. 
 
 The MuscuLO-SpiRAL NERVE, Fig. 108 (is), camuot be 
 traced at this stage of the dissection further than the fissure 
 which it enters with the superior profunda artery in the tri- 
 ceps extensor muscle. Before it enters the fissure it usually 
 gives off two or three small branches, which go to the muscles 
 and the skin on the inner part of the arm. 
 
 The belly of the biceps muscle may now be divided near 
 the junction of its two heads, and turned upwards and down- 
 wards, to expose the external cutaneous nerve and the bra- 
 chialis anticus muscle. The nerve, Fig. 108 (s), will be found 
 passing obliquely downwards and outwards between the bi- 
 ceps, and the brachialis anticus to become subcutaneous at 
 the outer part of the bend of the arm. It supplies branches 
 in its course to the coraco-brachialis, the biceps, and the bra- 
 chialis anticus. Its cutaneous branches may now be traced 
 for a short distance down on the forearm. 
 
 The BRACHIALIS ANTICUS, or INTERNUS, Fig. 109 (i e), arises 
 from the whole of the anterior surface of the humerus, from 
 the deltoid ridge to near the elbow-joint. It extends on both 
 sides beyond the biceps, but more on the inner than on the 
 outer side. It extends a little upwards in its origin on each 
 side of the insertion of the deltoid. Its fibres converge to 
 form a short tendon, which is inserted into the anterior and 
 lower part of the coronoid process of the ulna. The tendon 
 of the biceps lies partly upon it and to its outside. This 
 muscle assists the biceps in flexing the forearm on the arm ; 
 it also withdraws the synovial membrane from the angle of 
 
DISSECTION OF THE ABM. 
 
 255 
 
 the joint. In case of fracture of the coronoid process, it may 
 draw the fragment upwards. 
 
 When the tendons of -this muscle and the biceps are dis- 
 sected, and reflected downwards, the anterior part of the 
 elbow-joint is exposed, being cov- 
 ered only by a few ligamentous Fig. 109. 
 fibres. On the outside of the 
 brachialis anticus, and applied 
 closely to it, is the supinator 
 longu's muscle. When these mus- 
 cles are separated, the musculo- 
 spiral nerve and the superior pro- 
 funda artery will be found deeply 
 embedded between them. 
 
 The arm may now be turned 
 over for the purpose of dissecting 
 the back of it. The skin and su- 
 perficial fascia^ may be removed 
 by dissecting from either the in- 
 ner or outer side. After examin- 
 ing the brachial aponeurosis, it is 
 to be removed by dissecting in 
 the direction of the fibres of the 
 triceps extensor muscle, having 
 made that muscle tense by flex- 
 ing the forearm on the arm and 
 fixing the scapula. 
 
 The TRICEPS EXTENSOR, Fig. 
 110 (10, 14, 19), arises by three 
 heads, one from the scapula, and 
 two from the humerus. The first, 
 or longest head, arises from the in- 
 ferior costa of the scapula, occu- 
 
 AN ANTERIOR VIEW OF THE DEEP-SEATED MUSCLES OF THE ARM. 1. Clavicle. 
 2. Coracoid process of the scapula. 3. Acromion scapulae. 4. Head of the os 
 humeri. 5. Tendon of the long head of the biceps. 6. Upper portion of the co- 
 raco-brachialis. 7. Origin of the short head of the biceps. 8. Body of the coraco- 
 brachialis. 9. Insertion of the pectoralis major. 10. Latissimus dorsi. 11. In- 
 sertion of the deltoid. 12. Origin of the brachialis internus. 13. Insertion of the 
 coraco-brachialis. 14. Middle portion of the triceps. 15. Its lower anterior por- 
 tion. 16. Body of the brachialis anticus. 17. Internal condyle. 18, 19. Inser- 
 tion of the brachialis anticus. 20. Supinator radii longus. 21. Opening made 
 in the capsular ligament. 22. Cut tendon of the biceps at its insertion. 23. Su- 
 pinator radii brevis. 24. Aponeurosis. 
 
 24 
 
256 
 
 THE UPPEE EXTREMITY. 
 
 Fig. 110. 
 
 pying about an inch, commencing at the lower part of 
 the glenoid cavity, where it is slightly connected to the 
 capsular ligament. The second head arises from the pos- 
 terior part of the humerus, commencing just below the great 
 
 tuberosity, and extending 
 down to the external condyle, 
 from which it also arises in 
 connection with the anconeus ; 
 some of its fibres arise from 
 the external intermuscular 
 septum. The third and short- 
 est head arises from the inner 
 and back part of the humerus, 
 commencing just below and 
 behind the insertion of the 
 teres major, and extending 
 down to the internal condyle ; 
 some of its fibres come from 
 the internal intermuscular 
 septum. This head is some- 
 times called the brachialis ex- 
 ternus. These three heads 
 unite above the middle of the 
 arm, and form a large muscu- 
 lar belly, which ends in a 
 broad flat tendon, which is in- 
 serted into the olecranon pro- 
 cess, and connected with the 
 aponeurosis of the forearm. 
 This muscle, it will be seen, 
 occupies in its origin nearly 
 the whole of the posterior sur- 
 face of the humerus. It ex- 
 
 20 
 
 27 
 
 A LATERAL VIEW OF THE DEEP-SEATED MUSCLES ON THE BACK OP THE ARM. 
 1. Section of the clavicle. 2. Fossa supra-spinata of the scapula. 3. Base of 
 the scapula. 4. Coraco-acroraial ligament. 5. Coracoid process. 6. Origin of 
 the coraco-brachialis. 7. Section of the subscapularis muscle. 8. Head of the os 
 humeri. 9. Section of the body of the scapula. 10. Origin of the longhead of the 
 triceps. 11. Insertion of the latissimus dorsi. 12. Edge of the biceps flexor 
 cubiti. 13. Coraco-brachialis. 14, 15. Origin of the second head of the triceps. 
 16. Lower portion of the coraco-brachialis. 17. Body of the biceps. 18. Body of 
 the triceps. 19. Origin of the third head of the triceps. 20, 21. Its middle portion, 
 known as the brachialis externus. 22. Brachialis anticus. 23. Its insertion. 24. 
 Posterior ligament of the elbow. 25, 26. Origin of the flexors of the forearm. 27. 
 Prolongation of the tendon of the biceps to the fascia brachialis. 28. Olecranon. 
 
DISSECTION OF THE FOREARM. 257 
 
 tends the forearm on the arm, and draws the synovial mem- 
 brane from the joint when the forearm is extended. By its 
 long head it can act on the scapula. When the olecranon 
 process is broken off, it may draw it upwards. 
 
 The musculo-spiral nerve and superior profunda artery 
 may now be traced in the spiral groove through the triceps 
 muscle. To do this the muscle must be divided along the 
 course of the artery and nerve, when the branches given off 
 by them to the muscle, while passing through it, may be ob- 
 served. 
 
 The artery, on reaching the outer and lower part of the 
 arm, divides into several branches, which are distributed 
 about the elbow-joint, some of them anastomosing with the 
 anastornotic and Recurrent branches of the radial and poste- 
 rior interosseous arteries. 
 
 The nerve, when it leaves the triceps, gets between the 
 brachialis anticus and supinator longus muscles, between 
 which it goes to the bend of the arm, where it divides into 
 the radial and posterior interosseous. These divisions will 
 be traced in the dissection of the forearm. The internal and 
 external cutaneous branches of this nerve have been noticed. 
 Besides supplying muscular branches to the triceps extensor, 
 it sends filaments to the brachialis anticus, supinator longus, 
 and extensor carpi radialis longior. 
 
 In dissecting the forearm, it will be sufficient to remove, in 
 the first place, the skin in front down to the wrist. To do 
 this, the incision which was made to dissect the arm may be 
 continued down the middle of the forearm to the wrist, where 
 a transverse incision is to be made. The vessels and nerves 
 contained in the superficial fascia of the forearm, both in 
 front and on the back, are the same as have been seen in the 
 previous dissection. If they have been preserved, the stu- 
 dent will have no difficulty in tracing them. 
 
 The veins vary so much in their arrangement on the fore- 
 arm that it is hardly necessary to give any particular descrip- 
 tion of them. If they have been injected, they are distinctly- 
 seen and easily followed. In the living person, especially if 
 not fat, they are made prominent under the skin by com- 
 pressing the veins of the arm. They anastomose freely with 
 each other, forming a complete network. They are divided 
 into the radial, median, and ulnar. If the student should 
 wish to trace them and the cutaneous nerves, he must dissect 
 
 22* 
 
258 THE UPPER EXTREMITY. 
 
 the skin from the whole of the forearm and the back of the 
 hand at the same time. If this be done, the parts must be 
 kept covered with the integument or with wet cloths during 
 the intervals between the times allotted to dissecting. 
 
 The INTERNAL CUTANEOUS NERVE, Fig. 103 (e, 7), will be 
 found to continue down the forearm to the wrist; the anterior 
 branch, which was seen in connection with the median basilic 
 vein, on the front part, and the posterior branch on the back 
 part of the arm. These branches are situated on the ulnar 
 side. The anterior frequently anastomoses near the wrist with 
 a branch from the ulnar. 
 
 The EXTERNAL CUTANEOUS NERVE, Fig. 104 (4), is situated 
 on the radial side. Near the lower third of the forearm it 
 divides into two branches; one continues down to the integu- 
 ment, covering the ball of the thumb, and usually sends a 
 filament through the deep fascia to ramify on the radial ar- 
 tery ; it anastomoses with the radial nerve ; the other branch 
 is reflected round to the back of the forearm, where^ it also 
 anastomoses with the radial. 
 
 The lower external cutaneous branch of the musculo-spiral 
 nerve will be found passing down on the back of the forearm 
 to near the wrist. Branches of the radial and ulnar nerves are 
 distributed on the back of the hand and fingers ; but these 
 will be traced more readily from the main trunks. 
 
 Beneath the superficial fascia is a thick, dense aponeurosis, 
 Fig. 106, which invests the muscles of the forearm generally, 
 and furnishes fibrous sheaths for them separately. In struc- 
 ture, it is similar to the brachial aponeurosis. It is thicker 
 behind than in front, and in the upper than in the lower part 
 of the arm. It gives origin to muscular fibres both from its 
 under surface and from the processes which it sends in be- 
 tween the muscles, especially near the elbow. Its connections 
 with the brachial aponeurosis and with the fibrous expansions 
 from the tendons of the biceps and triceps, have been seen. 
 
 It is firmly attached to the olecranon process and to the 
 inner part of the ulna down to the styloid process. Below, 
 it is connected to the anterior and posterior annular liga- 
 ments. Between its attachments to the upper part of the 
 ulna there is a subcutaneous surface on that bone. Just 
 below the bend of the arm it stretches across a sulcus that is 
 
DISSECTION OF THE FOREARM. 259 
 
 formed by the anterior and posterior muscles of the forearm. 
 There is a deficiency in it in front of the elbow-joint which 
 allows the superficial fascia to join the deep areolar tissue, 
 and also the vena communicans to reach the deep-seated 
 veins, Fig. 106 ( 6 ). 
 
 When this aponeurosis is removed from the front of the 
 forearm as far as it can be done without interfering with the 
 muscles which partly arise from it, a sulcus will be observed 
 extending from the bend of the arm to the wrist, and separa- 
 ting the muscles on the back from those on the front of the 
 forearm. The upper part of this sulcus or depression is quite 
 broad and deep. *ln it are found the median nerva and the 
 bifurcation of the brachial artery, and the venae comites. The 
 radial artery and its corresponding veins, occupy this sul- 
 cus nearly its whole length ; the middle third contains also 
 the radial nerve. On the inner side of the lower two-thirds 
 of the forearm is another sulcus, which contains the ulnar 
 artery, its venae comites, and the ulnar nerve. 
 
 There are eight muscles on the anterior part of the forearm. 
 Two of these are inserted into the radius ; they are the pro- 
 nators. Two of them pass over the wrist-joint to be inserted 
 into two of the metacarpal bones ; these are carpal flexors. 
 Three of them go to the thumb and fingers; these are digital 
 flexors; the one going to the thumb is called the flexor longus 
 pollicis. The eighth one, the palmaris longus, is connected to 
 the annular ligament and palmar aponeurosis. 
 
 The student should familiarize himself with these muscles 
 by making the several movements with his own hand as they 
 respectively depend upon them. Three simple movements, 
 such as flexing the fingers and thumb, then the hand on the 
 forearm, and lastly, turning the hand on the palm, call into 
 action seven of these muscles. A familiarity with their 
 actions will assist him greatly in recollecting their names and 
 their relative position. In dissecting them, it is better to 
 commence on the radial side. The two most prominent 
 ones on this side are the pronator radii teres and flexor carpi 
 radialis. They form the inner boundary of the sulcus in 
 which lies the radial artery. 
 
 The PRONATOR EADII TERES, Fig. Ill (4), arises from the 
 internal condyle and aponeurosis of the forearm, and also by 
 
260 
 
 THE UPPEK EXTREMITY. 
 
 a small head, from tlie coronoid process of tlie ulna. The 
 median nerve passes between these two origins. Its fibres 
 pass obliquely downwards and outwards, to be inserted into 
 the outer part of the middle third of the radius. The upper 
 part of this muscle is superficial and prominent, while the 
 lower part is deep-seated, having the radial artery and nerve 
 in front of it. It rotates the radius inwards, and pronates 
 
 the hand; it may also assist in flexing 
 Fig. ill. tlie f orearm> 
 
 The FLEXOR CARPI EADIALIS, Fig. Ill 
 (5), arises from the internal condyle and 
 fascia, including the intermuscular sep- 
 tum, in common with the preceding mus- 
 cle. It forms a thick belly which becomes 
 tendinous near the middle of the forearm, 
 and continues so to its insertion into tlie 
 base of the metacarpal bone of the index 
 finger. The dissection of this muscle 
 beneath and below the annular ligament 
 with the lower part o the others which 
 go to the hand, must be postponed until 
 the palm of the hand is dissected. It 
 flexes the hand on the forearm, and may 
 assist in pronation and abduction of the 
 same. 
 
 The PALMARIS LONGUS, Fig. Ill (e), 
 is the next muscle to be dissected. Its 
 origin is similar to that of the flexor 
 carpi radialis. It forms a short belly, 
 which ends in a long, slim tendon ; this 
 extends down the forearm to the annular 
 ligament and palmar aponeurosis, into 
 which it is inserted. It is sometimes 
 
 SUPERFICIAL LAYER OF THE MUSCLES OF THE FOREARM. 1. The lower part 
 of the biceps, with its tendon. 2. A part of the brachialis anticus, seen beneath 
 the biceps. 3. A part of the triceps. 4. The pronator radii teres. 5. The flexor 
 carpi radialis. 6. The palmaris longus. 7. One of tho fasciculi of the flexor sub- 
 liinis digitorum : the rest of the muscle is seen beneath the tendons of the palmaris 
 longus and flexor carpi radialis. 8. The flexor carpi ulnaris. 9. The palmar 
 fascia. 10. The palmaris brevis muscle. 11. The abductor pollicis muscle. 12. 
 One portion of the flexor brevis pollicis; the leading line crosses a part of the 
 abductor pollicis. 13. The supinator longus muscle. 14. The extensor ossis m eta- 
 carpi, and extensor priini internodii pollicis, curving around the lower border of 
 the forearm. 
 
DISSECTION OF THE FOREARM. 261 
 
 absent. It flexes the hand, and makes tense the palmar apo- 
 neurosis. It is separated from the muscle beneath it by a 
 thick fascia. 
 
 The^FLEXOR CARPI ULNARIS, Fig. Ill (s),is placed on the 
 ulnar side of the palrnaris longus. It arises from the internal 
 condyle, and from the ulna nearly its whole length, and 
 from the fascia of the forearm. The ulnar nerve passes 
 between its origins from the condyle and the olecranon pro- 
 cess. Its origin from the lower part of the ulna is apo- 
 neurotic. It is inserted into the pisiform bone, and through 
 it into the metacarpal bone of the little finger ; it is, also, 
 connected by somexfibres with the muscles of the little finger. 
 Its tendon is much shorter than that of the flexor carpi 
 radialis. It flexes the hand, and assists in adduction. The 
 ulnar artery and nerve are situated along the outer border of 
 its inferior two-thirds. 
 
 The flexor carpi radialis and palmaris longus may now be 
 divided about three or four inches below their origin, and 
 turned upwards, detaching the fibres from the intermuscular 
 septa. The following muscle will then be exposed. 
 
 The FLEXOR SUBLIMIS or PERFORATUS DIGITORUM COM- 
 MUNIS, Fig. Ill (7), arises from the internal condyle, internal 
 lateral ligament, and from both bones of the forearm; from 
 the coronoid process of the ulna, and from the radius below 
 its tubercle ; it also obtains some fibres from intermuscular 
 septa. It forms a large muscular belly, which terminates in 
 four tendons a little below the middle of the forearm ; these 
 tendons pass under the annular ligament, the two on the 
 radial side being situated somewhat anterior to the others, 
 and through the palm of the hand, to be inserted into the 
 second row of phalangeal bones. It flexes the fingers, and 
 assists in flexing the hand and forearm. * 
 
 Before proceeding further with the dissection of the mus- 
 cles, the arteries and nerves of this.region should be examined. 
 Some of them have already been seen,* but not dissected and 
 studied. 
 
 There are three arteries in the forearm which extend from 
 the bend of the arm to the wrist. They are the radial, 
 the ulnar, an<f the anterior interosseous. From these 
 three arteries recurrent branches are given off, to anastomose 
 around the elbow-joint, with the anastomotic and two pro- 
 found branches of the'farachial artery. 
 
262 
 
 THE UPPER EXTREMITY. 
 
 Fig. 112. 
 
 The EADIAL ARTERY, Fig. 112 (i 2), although usually not so 
 arge as the ulnar, appears to be a continuation of the brachial. 
 
 It is covered in front merely by the 
 integument and aponeurosis; hence 
 it is superficial in its whole course. 
 It has one muscle in relation with 
 it on the outside, the supinator lon- 
 gus ; two on the inner side, the pro- 
 nator radii teres, and flexor carpi 
 radialis ; and five behind it, and on 
 which it lies. These are arranged 
 in the following order, commencing 
 above: the supinator brevis, pro- 
 nator radii teres, flexor sublimis 
 digitorum, flexor longus pollicis, 
 and the pronator quadratus ; below 
 this last muscle the artery rests on 
 the radius. 
 
 Near its commencement it gives 
 off quite a large branch, the radial 
 recurrent, Fig. 112 (is). This is 
 distributed to the muscles on the 
 outside of the elbow, and anasto- 
 moses with the superior profunda. 
 In its course down the arm it gives 
 off numerous branches, which are 
 not named. In the lower part of 
 the arm it sends off the superficial 
 volar branch, Fig. 112 (14), which 
 either passes over the mass of 
 muscle that forms the thenar of the 
 
 THE AETERIES OF THE FOREARM. 1. The lower part of the biceps muscle. 2. 
 The inner condyle of the humerus, with the humeral origin of the pronator radii 
 teres and flexor carpi radialis divided across. 3. The deep portion of the prouator 
 radii teres. 4. The supinator longus muscle. 5. The flexor longus pollicis. 6. 
 The pronator quadratus. 7. The flexor profundus digitorum. 8. The flexor carpi 
 ulnaris. 9. The annular ligament, with the tendons passing beneath it into the 
 palm of the hand ; the figure is placed on the tendon of the palmaris longus mus- 
 cle, divided close to its insertion. 10. The brachial artery. 11. The anastomotica 
 inosculating superiorly with the inferior profunda, and inferiorly with the anterior 
 ulnar recurrent. 12. The radial artery. 13. The radial recurrent artery inoscula- 
 ting with the termination of the superior profunda. 14. The superficialis volse. 
 15. The ulnar artery. 16. Its superficial palmar arch giving off digital branches to 
 three fingers and a half. 37. The magna pollicis, and radial artery. 18. The 
 posterior ulnar recurrent. 19. The anterior interosseous artery. 20. The posterior 
 interosseous, as it is passing through the interosseous membrane. 
 
DISSECTION OF THE FOREARM. 263 
 
 thumb to unite with the superficial palmar arch, or it may 
 end in branches to these muscles. Sometimes this branch is 
 very large, and forms a considerable portion of the palmar 
 arch, or it may divide into digital branches. In this dissec- 
 tion the radial artery disappears under the tendons of the 
 extensor muscles of the thumb. 
 
 Sometimes the radial artery leaves the anterior part of the 
 forearm, some distance above the carpus, and winds round 
 the radius to the back of the limb. In this case the pulse 
 cannot be felt at the wrist, at least on the radial side. 
 
 The radial artery is accompanied by vense comites, one on 
 each side of it. They require no particular description. 
 
 The relation of the EADIAL NERVE, Fig. 108 (ie), to the 
 radial artery, is such that it is required to be dissected and 
 studied at the same time. It is, as has been seen, the anterior 
 division of the musculo-spiral. It lies close to the inner side 
 of the supinator longus in the upper two-thirds of the fore- 
 arm, and is in direct relation with the radial artery only in 
 the middle third. In the upper third the nerve proceeds 
 from the outer part of the elbow, while the artery descends 
 from the centre of the bend of the arm. From these points 
 they converge so as to meet at the junction of the upper 
 with the middle third. They separate again at the junction 
 of the middle and lower thirds; the nerve passing beneath 
 the supinator longus, and over the radius to reach the back 
 part of the arm and hand. It is superficial in this part of 
 its course. The nerve can generally be felt beneath the skin, 
 during life, where it winds over the radius. 
 
 The radial nerve on the dorsum of the hand, Fig. 114 (4), 
 divides into an external and an internal branch. The external 
 branch supplies the integument on the outer and back part 
 of the thumb, and anastomoses with the external cutaneous 
 nerve. The internal branch passes obliquely over the exten- 
 sor tendons of the thumb, and is distributed to the integument 
 of the index and middle fingers, and sometimes to the radial 
 side of the ring finger, and the ulnar side of the thumb. It 
 anastomoses with the dorsal branch of the ulnar. 
 
 The ULNAR ARTERY, Fig. 112 (i 5), is situated on the 
 inner side of the arm. Its upper third has an oblique direc- 
 tion from above downwards, and from without inwards, and 
 is placed beneath the pronator radii teres, flexor carpi radi- 
 
264 THE UPPER EXTREMITY. 
 
 alls, palmaris longus, and flexor sublimis digitorum. The 
 depth and direction of it in this part of its course should be 
 observed. In the lower two-thirds of the forearm it is super- 
 ficial, and situated on the radial side of the flexor carpi ulna- 
 ris, which may serve as a guide for finding it. The flexor 
 sublimis lies on the outer side, and the flexor profundus be- 
 hind it. The median nerve is separated from the artery at 
 first by the coronoid head of the pronator radii teres, and 
 below this it is situated to the outer side of it. 
 
 It gives off a recurrent branch, Fig. 112 (11, is), which 
 usually divides into an anterior and posterior. The anterior 
 is small, and is distributed in front of the joint ; the posterior 
 is larger, and passes up beneath the flexor sublimis, to the 
 notch between the olecranon process and internal condyle, 
 where it meets with the ulnar nerve. It anastomoses with 
 the inferior profunda and anastomotic branches of the bra- 
 chial artery, and also sends small branches to the interior of 
 the joint. 
 
 Just below the origin of the recurrent, it gives off the 
 INTEROSSEOUS ARTERY, Fig. 112 (19). This soon divides 
 into the anterior and posterior interosseous ; the former passes 
 down the forearm resting on the interosseous ligament, while 
 the latter perforates the ligament, and is distributed to the 
 muscles on the back of the limb. These will be examined 
 at another time. There are no other branches given off from 
 the ulnar, which are named, until it reaches the carpus, where 
 it sends off a small metacarpal branch, which goes to the 
 dorsum of the little finger, and carpal branches, which anas- 
 tomose on the carpus, both in front and behind, with corre- 
 sponding branches of the radial artery. The ulnar artery 
 leaves the forearm by passing over the annular ligament close 
 to the radial side of the pisiform bone, where it is covered by 
 a few ligamentous fibres. 
 
 The ulnar, as was stated in connection with the bifurcation 
 of the brachial artery, may commence at any point on the arm. 
 An important anomaly is occasionally met with in its position; 
 instead of passing beneath the muscles it may pass over them, 
 or all of them except the palmaris longus. In this case it 
 may be even superficial to the aponeurosis of the forearm. 
 It also varies greatly in size ; the interosseous or radial, or 
 both of them, being at the same time larger or smaller than 
 
DISSECTION OF THE FOREARM. 
 
 265 
 
 Fig. 113. 
 
 common. It is important to understand the position of this 
 artery in bleeding at the bend of the arm. 
 
 The ulnar artery is accompanied by its venae comites. 
 
 The ULNAR NERVE, Fig. 113(3), enters the forearm through 
 the notch between the internal con- 
 dyle and olecranon process, and be- 
 tween two heads of the flexor carpi 
 ulnaris. It then passes obliquely 
 beneath the inner head, to join the 
 ulnar artery at the junction of the 
 upper with the middle third of the 
 forearm. It accompanies the artery 
 in the rest of its course, being situ- 
 ated on the ulnar side. It sends 
 articular filaments to the joint as it 
 passes over it ; muscular branches to 
 the flexor carpi ulnaris, and flexor 
 profundus digitorum ; and cutaneous 
 branches, one to the front of the 
 lower part of the forearm and hand, 
 and another to the dorsum of the 
 same parts. The latter branch leaves 
 it about two inches above the carpus, 
 and passing beneath the flexor carpi 
 ulnaris, Fig. 118 (e), gets round to 
 the back of the wrist and hand, where 
 it divides into several branches, 
 which are distributed to the little 
 and ring fingers. It also anasto- 
 moses with the radial. 
 
 The MEDIAN NERVE, Fig. 113 (i ), 
 after passing between the two heads 
 of the pronator radii teres, goes 
 down the middle of the forearm 
 between the flexor sublimis in front, 
 and the flexor profundus behind, 
 to within about two inches of the 
 wrist, where it gets on the outer side 
 of the tendons of the flexor sublimis, 
 and becomes superficial. It passes 
 beneath the annular ligament to en- 
 23 
 
 A VIEW OP THE NERVES ON 
 
 THE FRONT OF THE fFoREARM. 
 
 1. The median nerve. 2. Ante- 
 rior branch of the musculo-spiral 
 or radial nerve. 3. The ulnar 
 nerve. 4. Division of the median 
 nerve in the palm to the thumb, 
 first, second, and radial side of 
 the third finger. 5. Division of 
 the ulnar nerve to the ulnar 
 side of the third, and both sides 
 of the fourth finger. 
 
266 
 
 THE UPPER EXTREMITY. 
 
 \ 
 
 ter the palm of the hand. It supplies branches to all the 
 muscles on the front part of the forearm except the flexor 
 carpi ulnaris. The anterior interosseous is the largest branch. 
 The course of this is the same as that of the anterior inter- 
 osseous artery, with which it will be noticed. 
 
 Three -muscles remain to be dissected on the front of the 
 forearm ; these are the flexor profundus digitorum, flexor 
 longus pollicis, and the pronator quadratus. The first two 
 lie parallel to each other, and occupy 
 Fig. 114. the same plane ; there is no very 
 
 distinct line of demarcation or areo- 
 lar interspace between them. The 
 areolar tissue may be removed from the 
 anterior surface of both of them at the 
 same time. 
 
 The FLEXOR PROFUNDUS, or, PER- 
 FORANS DIGITORUM, Fig. 114 (4), arises 
 from the upper two thirds of the ulna 
 and the interosseous ligament contigu- 
 ous to it, and sometimes by a small 
 slip from the radius. It is a large 
 muscle, occupying the inner two thirds 
 of the anterior interosseous space ; near 
 the carpus it divides into four ten- 
 dons, which pass beneath the annular 
 ligament to go to the last row of pha- 
 langeal bones into which they are in- 
 serted. It flexes the last phalanges, and 
 otherwise assists the flexor sublimis in 
 flexing the fingers and hand. 
 
 The FLEXOR LONGUS POLLICIS, Fig. 
 114 (s), arises from the radius, com- 
 mencing just below the tubercle, and 
 extending to within about two inches 
 of its lower end ; also from the inter- 
 osseous ligament, and frequently by a 
 
 THE DEEP LAYER OF MUSCLES OP THE FOREARM. 1. The internal lateral li- 
 gament of the elbow-joint. 2. The anterior ligament. 3. The orbicular ligament 
 of the head of the radius. 4. The flexor profundus digitoruin muscle. 5. The flexor 
 longus pollicis. 6. The pronator quadratus. 7. The adductor pollicis muscle. 8. 
 The dorsal interosseous muscle of the middle finger, and palmar interosseous of the 
 ring finger. .St.; The dorsal interosseous muscle of the ring finger, and palmar in- 
 terosseous of the little finger. 
 
DISSECTION OF THE FOREARM. 
 
 267 
 
 Fig. 115. 
 
 round fasciculus from the coronoid process of the ulna. It 
 ends in a tendon which passes beneath the annular ligament, 
 and continues to the last phalangeal bone of the thumb, 
 into which it is inserted. It flexes the last phalanx of the 
 thumb. 
 
 The PRONATOR QUADRATUS, Fig. 114 (e), and 115 (9), is a 
 short, square muscle, placed beneath the preceding muscles. 
 It arises from the inner part of the 
 lower fifth of the ulna ; its fibres pass 
 transversely, or nearly so, across the 
 interosseous space, and are inserted into 
 the lower part of the radius, near its 
 outer border. It rotates the radius in- 
 wards, and thus pronates the hand. 
 
 The ANTERIOR INTEROSSEOUS AR- 
 TERY, Fig. 112 (i 9), may now be exam- 
 ined, and also its accompanying nerve. 
 They usually rest* on the interosseous 
 ligament near the median line. The 
 artery passes through the ligament near 
 the pronator quadratus to the dorsum 
 of the carpus, where it divides into 
 several small branches. Occasionally 
 it gives off quite a large branch, which 
 accompanies the median nerve down 
 the forearm. 
 
 A VIEW OF THE 
 
 The ANTERIOR INTEROSSEOUS NERVE, 
 
 Fig. 108 (i 3), terminates in a filament TORS OP THE FOREARM i. 
 
 to the pronator quadratus and one to ftjT7a23SJi 
 
 the carpal articulations. Both the ar- of the elbow. 5. interosse- 
 
 tery and nerve give off branches to the T u g ament - 6. origin of 
 
 J , i i T- -i the pronator radii teres. 
 
 niUSCleS Which lie COntlgUOUS tO them 7. Its insertion. 8. Supi- 
 
 in the interosseous space. nator radii brevis - 9. Pro- 
 
 nator quadratus. 10. Ten- 
 
 The back of the forearm may now don of the bice P s - n - Car - 
 be examined, and, at the same time, pal 
 the back of the hand. It is not necessary to refer again 
 to the fascia or the subcutaneous vessels and nerves of 
 this region, as they were described in connection with the 
 anterior part of the forearm. The remarks which were 
 made with reference to the study of the muscles on the 
 
268 THE UPPER EXTREMITY. 
 
 forepart of tlie forearm will apply equally to those on the 
 back part. Most of them are antagonist muscles to those 
 already learned. There are eleven, including the anconeus, 
 and allowing no distinct muscle for the little finger. In 
 arranging them according to their action, and comparing 
 them with the flexors and pronators, the student will find 
 two supinators opposed to the two pronators ; three carpal 
 extensors to the two carpal flexors ; three extensors of the 
 thumb, one for each joint, to the single long flexor ; one 
 common extensor of the fingers to the two common flexors. 
 The extensor of the index finger and the anconeus have no 
 corresponding muscles in front. 
 
 Six of these muscles are situated superficially, and may 
 be dissected in the following order : 
 
 The ANCONEUS, Fig. 116 (i i), and Fig. 117 (4), is a small 
 triangular-shaped muscle, situated on the posterior part of 
 the elbow-joint. It arises from the external condyle of the 
 humerus, immediately below the origin of the lower fibres 
 of the triceps extensor, and from the external lateral liga- 
 ment ; it passes obliquely downwards and somewhat inwards, 
 and is inserted into a triangular space on the upper and pos- 
 terior part of the ulna. It assists the triceps in extending 
 the arm, and might be considered an appendage to that 
 muscle. It partly covers the elbow-joint posteriorly. 
 
 The SUPINATOR LONGUS, Fig. 116 (4), arises from the ridge 
 which extends upwards from the external condyle, and from 
 the external intermuscular septum of the brachial aponeurosis ; 
 its origin commences just below the insertion of the deltoid 
 and ends about an inch and a half above the condyle. Its 
 fibres terminate in a tendon about the middle of the forearm, 
 which goes down to be inserted into the lower end of the 
 radius at the base of the styloid process. It rotates the radius 
 backwards so as to supinate the hand. 
 
 The EXTENSOR CARPI EADIALIS LONGIOR, Fig. 116 (5), 
 arises from the external condyloid ridge, immediately below 
 the preceding muscle, and becomes tendinous near the junc- 
 tion of the upper with the middle third of the forearm. 
 
 The EXTENSOR CARPI EADIALIS BREVIOR, Fig. 116 (e), 
 arises from the external condyle, and from the aponeurosis 
 which partly surrounds it. It becomes tendinous a little 
 
DISSECTION OF THE FOKEARM. 
 
 269 
 
 Fig. 116. 
 
 lower down than the preceding muscle. The tendons of these 
 
 two carpal extensors are partly covered by the supinator 
 
 longus, and are so closely connected to each other that they 
 
 appear to form a single tendon until they get near the wrist, 
 
 where they separate, and, passing beneath the tendons of two 
 
 of the extensor muscles of the thumb, 
 
 and then through the same canal in the 
 
 posterior annular ligament, are inserted, 
 
 the longior into the base of the meta- 
 
 carpal bone of the index finger, and 
 
 the brevior into the rnetacarpal bone 
 
 of the second finger. They extend the 
 
 hand on the forearm, and also abduct 
 
 it. The groove which their tendons 
 
 occupy in passing over the radius is 
 
 lined by a bursa. 
 
 The EXTENSOR DIGITORUM COMMU- 
 NIS, Fig. 116 (e), is placed on the ulnar 
 side of the muscles just described. It 
 arises from the external condyle, from 
 the aponeurosis around it, and from the 
 ulna. About the middle of the fore- 
 arm it divides into four small muscles, 
 each of which ends in a tendon. The 
 four tendons passing through a groove 
 on the radius, and a canal beneath 
 the annular ligament, expand on the 
 back of the hand, being connected to- 
 gether more or less by tendinous 
 fibres, and finally are inserted into all 
 the phalanges. On the dorsum of the 
 fingers they are connected with the 
 tendons of the interossei and lumbri- 
 
 THE SUPERFICIAL LAYER OF MUSCLES OF THE POSTERIOR ASPECT OF THE FORE- 
 ARM.!. The lower part of the biceps. 2. Part of the brachialis anticus. 3. The 
 lower part of the triceps, inserted into the olecranon. 4. The supinator longus. 
 5. The extensor carpi radialis longior. 6. The extensor carpi radialis brevior. 7. 
 The tendons of insertion of these two muscles. 8. The extensor communis digito- 
 rum. 9. The extensor minimi digiti. 10. The extensor carpi ulnaris. 11. The 
 anconeus. 12. Part of the flexor carpi ulnaris. 13. The extensor ossis metacarpi 
 and extensor primi internodii muscles lying together. 14. The extensor secundi in- 
 ternodii; its tendon is seen crossing the two tendons of the extensor carpi radialis 
 longior and brevior. 15. The posterior annular ligament. The tendons of the com- 
 mon extensor are seen upon the back of the hand, and their mode of distribution 
 on the dorsum of the fingers. 
 
 23* 
 
270 
 
 THE UPPER EXTREMITY. 
 
 Fig. 117. 
 
 cales. It extends all the fingers. The extensor minimi 
 digiti, Fig. 116 (9), may be considered a part of this muscle, 
 having the same origin, course, and insertion. Its tendon 
 may pass through a separate canal beneath the annular liga- 
 ment. 
 
 The EXTENSOR CARPI ULNARIS, Fig. 116 (i o), arises from 
 the external condyle, from the aponeurosis around it, and 
 from the ulna below the insertion of the anconeus. It 
 becomes entirely tendinous near the 
 carpus, passes through a groove be- 
 hind the styloid process of the ulna 
 and a separate canal beneath the an- 
 nular ligament, and is inserted into the 
 base of the metacarpal bone of the 
 little finger. It extends the hand, and 
 adducts it. As an extensor, it acts in 
 conjunction with the radio-carpal ex- 
 tensors; as an adductor of the hand 
 it co-operates with the flexor carpi 
 ulnaris, although, as an extensor, it 
 opposes this muscle. 
 
 The student will meet with some 
 difficulty in separating the extensor 
 muscles in the upper part of the fore- 
 arm, on account of their arising from 
 the same aponeurosis and intermuscu- 
 lar septa. When they are separated 
 from each other the dissection will 
 necessarily appear rough and uneven. 
 The remaining five muscles on the 
 back of the forearm are deep-seated, 
 and, except the anconeus, small, com- 
 pared with those which have been dis- 
 sected. The arteries are the posterior 
 interosseous and the radial, together 
 with some small branches on the dor- 
 
 THE DEEP LAYER OP MUSCLES ON THE POSTERIOR ASPECT OF THE FOREARM. 
 1. The lower part of the humerus. 2. The olecranon. 3. The ulna. 4. The 
 anconeus muscle. 5. The supinator brevds muscle. 6. The extensor ossis meta- 
 carpi pollicis. 7. The extensor primi internodii pollicis. 8. The extensor secundi 
 internodii pollicis. 9. The extensor indicis. 10. The first dorsal interosseous 
 muscle. The other three dorsal interossei are seen between the metacarpal bones 
 of their respective fingers. 
 
DISSECTION OF THE FOREARM. 
 
 271 
 
 Fig. 118. 
 
 sum of the hand. The nerves are the posterior interosseous, 
 and the cutaneous branches of the radial and ulnar on the 
 lower part of the limb, which last were examined directly 
 after the removal of the skin. 
 
 The SUPINATOR BREVIS, Fig. 117 (5), is a short flat muscle, 
 which arises from the external condyle, the ulna for a short 
 distance below the lesser sigmoid cavity, and the external late- 
 ral and orbicular ligaments. The fibres pass obliquely down- 
 wards and outwards, and are inserted into the radius between 
 its cervix and the insertion of the pro- 
 nator radii teres. To expose it, the 
 supinator longus and the radio-carpal 
 extensors must be divided a few 
 inches below the elbow, and reflected 
 upwards ; the anconeus should also be 
 dissected up. 
 
 The POSTERIOR INTEROSSEOUS AR- 
 TERY will be seen just below the supina- 
 tor brevis. It descends to the wrist, 
 lying on the extensor muscles of the 
 thumb and index finger. It gives off, in 
 the upper part of its course, the poste- 
 rior recurrent branch, which ascends be- 
 neath the anconeus to anastomose with 
 the superior profunda,and to send twigs 
 to the elbow-joint. It supplies the mus- 
 cles on the back of the forearm, and 
 anastomoses on the dorsum of the wrist 
 with branches from the radial, ulnar, 
 and anterior interosseous arteries. 
 
 The POSTERIOR INTEROSSEOUS 
 NERVE, Fig. 118 (2), will be found 
 passing through the supinator brevis, 
 and then descending with the artery 
 to near the middle of the forearm, 
 where it dips down to the interosseous 
 ligament, on which it continues to the 
 
 A VIEW OP THE NERVES ON THE BACK OF THE FOREARM AND HAND. 1, 1. The 
 ulnar nerve. 2, 2. Posterior interosseous nerve. 3. Humeral cutaneous branch. 
 1. Dorsal branch of the radial nerve. 5, 5. A back view of the digital nerves. 6. 
 Dorsal branch of the ulnar nerve. 
 
272 THE UPPER EXTREMITY. 
 
 wrist. It terminates in filaments to the carpal articula- 
 tions. 
 
 In its course it sends filaments to all the muscles on the 
 back of the limb, except the supinator longus, extensor carpi 
 radialis longior, and anconeus. 
 
 The EXTENSOR Ossis METACARPI POLLICIS, Fig. 117 (e), 
 is the first deep muscle below the supinator brevis. It arises 
 from the posterior and upper part of the radius and ulna, and 
 from the intermediate portion of the interosseous ligament. 
 Its tendon descends obliquely outwards over the lower part 
 of the radius, and the carpus to be inserted into the base of 
 the metacarpal bone of the thumb. It very frequently divides 
 into two tendons, one of which goes to the trapezium. 
 
 The EXTENSOR PRIMI INTERNODII POLLICIS, Fig. 117 (7), 
 is the next small muscle. It arises from the radius and inter- 
 osseous ligament, immediately below the preceding muscle, 
 with which its tendon is closely connected. It is inserted into 
 the base of the first phalangeal bone of the thumb. The line of 
 separation between these two muscles is often very indistinct, 
 except near their insertion. Their tendons pass through the 
 same canal in the posterior annular ligament. 
 
 The EXTENSOR SECUNDI INTERNODII POLLICIS, Fig. 117 (e), 
 arises from the middle third of the ulna and the interosseous 
 ligament contiguous to it. Its tendon passes down over the 
 lower end of the radius, about half an inch to the ulnar side 
 of the tendons of the other two extensors of the thumb, 
 and continues to the last phalanx, into which it is inserted. 
 The last three muscles extend the three joints of the thumb ; 
 the first two also act as abductors of it. The student should 
 observe the situation of the tendons of these muscles in his 
 own wrist. They are seen very distinctly through the skin 
 when the thumb is forcibly extended. They have an im- 
 portant relation to the radial artery, which passes beneath 
 them, and which will shortly be noticed. 
 
 The EXTENSOR INDICIS, or INDICATOR, Fig. 117 (9), is the 
 only muscle left. It arises from the ulna and interosseous 
 ligament just below the muscle last described, and forms a 
 small tendon which passes through the annular ligament with 
 the common extensor of the fingers ; it joins and is inserted in 
 common with, the tendon of that muscle which is appropriated 
 to the index finger. Its use is to extend that finger by itself. 
 
THE PALM OF THE HAND. 273 
 
 The RADIAL ARTERY may now be examined in its course 
 over the wrist. It winds round the external lateral ligament 
 of the wrist-joint, below the radius, and enters a triangular 
 space between the tendons of the extensor muscles of the 
 thumb ; leaving this space, where it is covered merely by the 
 skin and fascia, it gets between the metacarpal bones of the 
 thumb and index finger, and then disappears between the 
 two heads of the first dorsal interosseous muscle, and enters 
 the palm of the hand. It gives off the dorso-carpal branch, 
 which passes transversely beneath the tendons, on the back 
 of the wrist, to anastomose with the dorso-carpal branch of 
 the ulnar. From the arch thus formed, branches pass up 
 to anastomose with the interosseous arteries; others descend 
 in the interosseous spaces to the fingers. The branch, in the 
 second interosseous space, is sometimes quite large. Other 
 small branches are given off from it to the back of the thumb 
 and forefinger. 
 
 The canals in the posterior annular ligament may now 
 be examined. There are six of them altogether. They are 
 lined by synovial membrane so as to allow the tendons to 
 glide through them with perfect facility, while each is kept 
 in its proper place. The synovial membrane usually extends 
 some distance above and below the ligament. Between the 
 different openings the ligament is firmly attached to the bone 
 beneath. The examination of the dorsal interosseous muscles 
 may be postponed until the palm of the hand has been dis- 
 sected. 
 
 THE PALM OF THE HAND. 
 
 To dissect the front part of the hand it should be placed 
 with the palm upwards ; the thumb and fingers should also 
 be extended and fixed with hooks. It is immaterial in what 
 direction the incisions are made for the purpose of removing 
 the skin. In dissecting it from the inner part of the palm, 
 it is to be recollected that the following muscle is inserted 
 into the integument : 
 
 The PALMARIS BREVIS arises from the annular ligament 
 and palmar aponeurosis, and passes, in fasciculi, transversely 
 inwards, and is inserted into the skin in front of the meta- 
 carpal bone of the little finger near the inner border of the 
 
274 THE UPPER EXTREMITY. 
 
 hand. Its action is to increase the depth of the hollow of the 
 palm of the hand. 
 
 Two cutaneous nerves, one from the ulnar, and the other 
 from the median, are distributed to the skin in the palm. 
 These branches were noticed in the dissection of the median 
 and ulnar nerves in the lower part of the forearm, as passing 
 over the annular ligament to the hand. 
 
 Between the skin and the palmar fascia there is usually 
 considerable fat, which must be dissected from the latter. 
 The fascia is of a triangular shape, narrow above and broad 
 below. It is attached to the annular ligament above; be- 
 low it divides into four processes, one for each finger, and 
 each of these again is subdivided into two others, which dip 
 down to be inserted into the sheaths of the tendons of the 
 flexor muscles of the fingers, and the ligaments of the joints 
 beneath. The first mentioned processes are connected by 
 transverse fibres, which form arches over the lumbricales 
 and the digital arteries and nerves. The fascia is bound 
 down by fibres which pass between the tendons to be 
 attached to the metacarpal bones. It is very thin 9ver the 
 muscles of the thumb and little finger. This fascia should 
 be noticed with reference to the formation of pus beneath it, 
 and punctured wounds in the palm of the hand. 
 
 The SUPERFICIAL PALMAR ARCH, Fig. 112 (ie), and its 
 branches, are situated immediately beneath the palmar fascia. 
 These, with the branches of the median and ulnar nerves, should 
 be dissected next. The arch is readily exposed by following 
 the ulnar artery, or the superficialis volae, over the annu- 
 lar ligament. It is situated nearly in the centre of the 
 palm, with its convexity looking towards the fingers. The 
 principal branches from the arch are the four metacarpal. 
 Three of these correspond respectively with the second, third, 
 and fourth interosseous spaces, while the fourth one passes 
 down to the ulnar side of the little finger. 
 
 Each of these arteries, except the one which goes to the 
 ulnar side of the little finger, divides at the lower end of the 
 space which it occupies, into two digital branches these extend 
 along the contiguous sides of the fingers to their extremities. 
 
 Those of the same finger anastomose freely with each 
 other, especially in its pulpy portion. It usually requires 
 some patience to dissect out these arteries in consequence of 
 
THE PALM OF THE HAND. 275 
 
 the close adherence of cellulo-adipose substance to them. 
 The superficial palmar arch is connected at its outer extre- 
 mity with the superficialis volae, and another branch which 
 proceeds from the radial artery to the index finger. Besides 
 the branches already mentioned, there are several smaller 
 ones derived from this arch, but they require no special 
 notice. 
 
 Although the radial artery cannot be traced at the present 
 time into the deep palmar arch, its digital branches to the 
 thumb and forefinger may now be exposed. They occupy a 
 position on the thumb and radial side of the forefinger, simi- 
 lar to that of the other digital branches on the fingers. It 
 will be observed that the index finger is supplied equally by 
 the radial and ulnar arteries. 
 
 The ULNAE NEKVE, Fig. 113 (5), will be found entering 
 the palm along with the ulnar artery, but instead of forming 
 an arch, it divides into a deep and superficial branch. The deep 
 one passes deeply into the palm of the hand, and across it be- 
 neath the common flexor tendons to the muscles of the thumb. 
 It perforates the short flexor of the little finger, and in its 
 course supplies branches to the muscles of the little finger, the 
 third and fourth lumbricales, and the corresponding inter- 
 osseous muscles, terminating in the abductor indicis, adductor 
 pollicis, and the inner head of the flexor brevis pollicis. The 
 superficial one sends a branch to the inner side of the little 
 finger, the short flexor of which it perforates. It then divides 
 into two branches to supply the contiguous sides of the little 
 and ring fingers ; it also sends a small branch to join the 
 median nerve. 
 
 The MEDIAN NERVE, Fig. 113 (4), enters the palm of the 
 hand resting on the tendons of the long digital flexors. 
 Having sent a branch to those muscles of the thumb which 
 are not supplied by the deep branch of the ulnar, it divides 
 into two parts, from which proceed five branches, to be dis- 
 tributed as follows : 
 
 One branch goes to each side of the thumb ; one to the 
 radial side of the index finger ; the other two subdivide each 
 into two branches, to supply the opposing sides of the index, 
 middle, and ring fingers. They are expended mainly in the 
 skin, which, at the extremities of the fingers, is supplied by 
 them on the dorsal as well as on the palmar aspect. The digital 
 
276 THE UPPER EXTREMITY. 
 
 arteries and nerves may be dissected at the same time. The 
 nerves will be found to be more superficial than the arteries. 
 
 The tendons of the long flexors of the thumb and fingers, 
 and the lumbricales, may now be examined. 
 
 Beneath the annular ligament the tendons are surrounded 
 by the carpal bursse, of which there are two ; one for the 
 tendons of the fingers, and one for the tendon of the thumb. 
 The former projects between the different tendons, extends 
 some distance above the annular ligament, especially behind, 
 and is prolonged downwards in the form of four pouches, one 
 for the two tendons of each finger. The bursa on the flexor 
 tendon of the thumb extends much further, both above 
 and below the annular ligament. A proper examination of 
 this bursa requires a division of the annular ligament. This 
 may be done now, or postponed until the muscles of the 
 thumb and little finger have been dissected. 
 
 The tendons of the digital flexors, Fig. 119, pass down 
 in front of the phalanges ; those of the sublimis to the 
 second, and those of the profundus to the last row. They 
 are kept in place by sheaths, composed of a dense fibrous 
 structure, which is firmly attached to the margins of the 
 groove on the palmar aspect of each of the phalanges of the 
 first and second rows. In front of the articulations these 
 sheaths are deficient or entirely absent. Each of these 
 fibrous canals is lined by a synovial membrane, which is re- 
 flected around the tendons. 
 
 The tendons of the flexor sublimis split, Fig. 119 (s), nearly 
 opposite to the middle of each phalanx of the first row, and 
 then reunite to be inserted into those of the second. The 
 tendons of the flexor profundus pass through the openings 
 thus formed ; above the slits they lie behind the tendons of 
 the sublimis, but get in front below them ; they are inserted 
 into the last row of phalanges. 
 
 The tendon of the flexor longus pollicis passes over the 
 trapezium, and between the two heads of the flexor brevis 
 pollicis, and through a fibrous sheath to be inserted into the 
 last phalangeal bone of the thumb. 
 
 The LUMBRICALES, Fig. 119 (7, 7), are four small muscles 
 which arise from the external sides of the tendons of the 
 flexor profundus. Their tendons pass downwards and back- 
 wards over the radial side of the metacarpo-phalangeal 
 
THE PALM OF THE HAND. 
 
 277 
 
 articulations, and are expanded on the back of the first row 
 of phalanges, 'in connection with the tendons of the common 
 extensor of the fingers. Their action cannot well be defined; 
 it will depend on the action of other muscles, whether they 
 assist in flexing or extending, in abducting or adducting the 
 fingers. 
 
 The four short muscles of the thumb may now be dissected. 
 They form the palmar or thenar eminence, and are named 
 according to their action on the thumb. 
 
 The ABDUCTOK POLLICIS, Fig. 119 (2, 2), is the most super- 
 ficial and external. It arises from the annular ligament and 
 trapezium, and is inserted into the base of the first phalanx. 
 It abducts the thumb. 
 
 The FLEXOR Ossis METACARPI, or, OPPONENS POLLICIS, 
 Fig. 119 (a), is partly overlapped by the preceding muscle, 
 which, consequently, should be raised before the opponens 
 
 Fig. 119. 
 
 THE MUSCLES OF THE HAND. 1. 
 The annular ligament. 2, 2. The ori- 
 gin and insertion of the abductor pol- 
 licis muscle ; the middle portion has 
 been removed. 3. The flexor ossis 
 metacarpi, or opponens pollicis. 4. 
 One portion of the flexor brevis polli- 
 cis. 5. The deep portion of the flexor 
 brevis pollicis. 6. The adductor pol- 
 licis. 7, 7. The lurnbricales muscles, 
 arising from the deep flexor tendons, 
 upon which the numbers are placed. 
 The tendons of the flexor sublimis have 
 been removed from the palm of the 
 hand. 8. One of the tendons of the 
 deep flexor, passing between the two 
 terminal slips of the tendon of the flexor 
 sublimis, to reach the last phalanx. 9. 
 The tendon of the flexor longus pol- 
 licis, passing between the two portions 
 of the flexor brevis to the last phalanx. 
 10. The abductor minimi digiti. 11. 
 The flexor brevis minimi digiti. The 
 edge of the flexor ossis metacarpi, or 
 adductor minimi digiti, is seen project- 
 ing beyond the inner border of the 
 flexor brevis. 12. The prominence of the pisiform bone. 13. The first dorsal in- 
 terosseous muscle. 
 
 is dissected. It arises from the annular ligament and os 
 scaphoides, and is inserted into the metacarpal bone of the 
 24 
 
278 THE UPPER EXTREMITY. 
 
 thumb. It opposes the thumb to the fingers, as in grasping 
 anything in the palm. 
 
 The FLEXOR BREVIS POLLICIS, Fig. 119 (4, s), is the 
 largest of the four short muscles of the thumb. It consists 
 of two parts, separated by the tendon of the flexor longus 
 pollicis. The anterior part is not unfrequently inseparably 
 connected with the opponens, and the posterior with the 
 adductor pollicis. Thej^rs^ arises from the annular ligament, 
 trapezium, and scaphoides ; the second from the trapezoides, 
 magnum, and base of the third metacarpal bone. The two 
 parts unite and are inserted by two short tendons into the first 
 phalanx. A sesamoid bone is commonly found in each of 
 these tendons. As its name implies, it flexes the thumb. 
 
 The ADDUCTOR POLLICIS, Fig. 119 (e), arises from the meta- 
 carpal bone of the middle finger, nearly its whole length, 
 and is inserted, with the posterior part of the flexor brevis, 
 into the first phalanx. It approximates the thumb to the 
 forefinger. 
 
 There are three short muscles in the palm which belong 
 to the little finger. They form the hypothenar eminence. 
 
 The ABDUCTOR MINIMI DIGITI, Fig. 119 (10), arises from 
 the annular ligament and pisiform bone, and is inserted into 
 the base of the first phalanx. It is the most superficial and 
 internal of the short muscles of the little finger. It separates 
 the little from the ring finger. 
 
 The FLEXOR BREVIS MINIMI DIGITI, Fig. 119 (n), arises 
 from the annular ligament and unciform bone, and is inserted 
 into the first phalanx. It is closely connected to the abductor. 
 It flexes the little finger. 
 
 The ADDUCTOR MINIMI DIGITI, Fig. 119 (i i), arises from 
 the os unciforme and annular ligament, and is inserted into the 
 metacarpal bone of the little finger. It may be compared 
 to the opponens pollicis. It lies behind the flexor brevis. It 
 draws the little to the ring finger. 
 
 The annular ligament may now be examined and divided, 
 and the tendons of the long flexors with the lumbricales re- 
 moved from the palm, so as to expose the deep palmar arch 
 and the interosseous muscles. 
 
 The ANNULAR LIGAMENT, Fig. 119 (i), is attached on the 
 inner side to the pisiform bone, and the tendon of the flexor 
 
THE PALM OF THE HAND. 279 
 
 carpi ulnaris, and also to the unciform bone ; the ulnar nerve 
 passes between these attachments. Externally it is connected 
 to the scaphoides and trapezium. Its fibres are, for the most 
 part, transverse. Its connection with the aponeuroses of the 
 forearm and palm, and with the palmaris longus, and the 
 short muscles of the thumb and little finger have already 
 been seen. It subtends the deep sulcus in the anterior part 
 of the carpus, and serves to keep the flexor tendons which 
 pass beneath it in their proper place ; it also strengthens the 
 carpus. 
 
 The EADIAL ARTERY reaches the palm of the hand by pass- 
 ing between the heads of the abductor indicis. Before termi- 
 nating in the deep palmar arch, it gives off a digital branch 
 to the index finger, and the arteria magna pollicis, Fig. 118 
 (17), which divides into two branches for the thumb. The 
 former will be found passing behind the flexor brevis pollicis 
 and adductor pollicis, and over the abductor indicis ; the 
 latter passes between the abductor indicis and short flexor of 
 the thumb. Their distribution was seen in the dissection of 
 the branches of the superficial arch. 
 
 The DEEP PALMAR ARCH rests on the metacarpal bones 
 and interosseous muscles, to which, and the carpus, it sends 
 small branches. Three 'metacarpal branches are sent down- 
 wards from it along the interosseous spaces to anastomose 
 with the digital branches of the superficial arch. It ends 
 on the ulnar side by joining a deep branch from the ulnar 
 artery. 
 
 The deep branch of the ulnar nerve may be traced at the 
 same time with the deep palmar arch. 
 
 There are SEVEN INTEROSSEOUS MUSCLES three palmar, 
 and four dorsal. They occupy the spaces between the meta- 
 carpal bones, being separated from each other by a thin apo- 
 neurosis. The three palmar are called adductors, because 
 they approximate the forefinger and the little and ring 
 fingers to the middle finger, which is made to represent the 
 median line of the hand. 
 
 The adductor of the forefinger, Fig. 120 (i), arises from the 
 ulnar side of the upper and front part of the second meta- 
 carpal bone, and is inserted into the first phalanx of the fore- 
 finger. 
 
 The adductor of the ring finger, Fig. 120 (2), arises from the 
 
280 
 
 THE UPPEE EXTREMITY. 
 
 radial side of the fourth metacarpal bone, and is inserted into 
 the first phalanx of the ring finger. 
 
 The adductor of the little finger, Fig. 120 (3), arises from the 
 radial side of the fifth metacarpal bone, and is inserted into 
 the first phalanx of the little finger. 
 
 The arrangement of the four dorsal interosseous muscles 
 is quite different. Two of them are abductors, while the 
 other two act on the middle finger. Each one arises by 
 two heads. 
 
 The abductor of the forefinger, Fig. 121 (i), arises from the 
 first and second metacarpal bones, and is inserted into the 
 base of the first phalanx of the index finger. 
 
 Fig. 120. 
 
 Fig. 121. 
 
 THE PALMAR INTEROSSEOUS MUS- 
 CLES ARE SHOWN IN CONNECTION WITH 
 
 THE BONES OP THE RIGHT HAND. 
 
 THE DORSAL INTEROSSEOUS MUS- 
 CLES OF THE RIGHT HAND, AND THEIR 
 CONNECTION WITH THE TENDONS OF THE 
 LONG EXTENSOR MUSCLES OF THE FIN- 
 GERS, ARE HERE REPRESENTED. 
 
 The abductor of the ring finger, Fig. 121 (4), arises from the 
 fourth and fifth metacarpal bones, and is inserted into the first 
 phalanx of the ring finger. 
 
 The other two arise, Fig. 121 (2, 3), one from the second and 
 third, and the other from the third and fourth metacarpal 
 bones ; they are both inserted into the first phalanx of the 
 middle finger. It will be observed that these are the only 
 
THE ELBOW-JOINT. 281 
 
 interosseous muscles appropriated to the middle finger. One 
 will move it towards the forefinger, and the other towards 
 the ring finger. The terms "abductor" and "adductor" 
 cannot be applied to these two muscles, unless it is done with 
 reference to the median line of the body. 
 
 The tendons of the interosseous muscles are connected to 
 those of the long extensors of the fingers, and serve to keep 
 the latter applied to the dorsal surface of the phalanges ; 
 thus supplying the place of fibrous sheaths. When the 
 fingers are flexed, they lose the power of abducting or ad- 
 ducting them. They contribute to the strength of the meta- 
 carpo-phalangeal articulations. The adductor and abductor 
 of the thumb differ from those of the fingers in having no 
 attachment to its metacarpal bone. The fibres of the ad- 
 ductor pollicis have a direction nearly transverse to the 
 axis of the thumb, which adds greatly to the power of this 
 muscle. 
 
 The remaining articulations of the upper extremity may 
 now be examined. 
 
 The ELBOW-JOINT is formed by the humerus above, and 
 the ulna and radius belowi The radius and ulna also 
 articulate with each other so as to form a movable joint. 
 The articular surface of the humerus is adapted to flexion 
 of the forearm, and, at the same time, allows the radius to 
 rotate on the ulna. Thus it will be seen that this articula- 
 tion admits of two distinct movements. It contains only 
 one synovial membrane, which lines the inner surface of the 
 parietes of the joint. The ligaments are the following : 
 
 The EXTERNAL LATERAL LIGAMENT, Fig. 123 (4), arises 
 from the external condyle of the humerus, passes downwards, 
 and is inserted into the annular ligament. 
 
 The INTERNAL LATERAL LIGAMENT, Fig. 122 (2), arises 
 from the internal condyle of the humerus ; its fibres diverge 
 as they pass downwards to be inserted into the base of the 
 coronoid process of the ulna. 
 
 The ANTERIOR LIGAMENT, Fig. 123 (7), is thin and mem- 
 branous. Its fibres arise from the margin of the fossa for 
 the reception of the coronoid process of the ulna, pass 
 downwards in front of the joint, and are inserted into the 
 
282 
 
 THE UPPER EXTREMITY. 
 
 coronoid process, and the annular ligament. The removal 
 of this ligament affords a very good view of the interior of 
 the joint. 
 
 Fig. 122. 
 
 Fig. 123. 
 
 AN INTERNAL VIEW OP THE ELBOW- 
 JOINT. 1. The anterior ligament. 2. 
 The internal lateral ligament. 3. The 
 coronary ligament. 4. The ligamentum 
 teres. 5. The interosseous ligament. 
 6. The internal condyle, which conceals 
 the posterior ligament behind. 
 
 AN EXTERNAL VIEW OF THE ELBOW- 
 JOINT. 1. The humerus. 2. The ulna. 
 3. The radius. 4. The external lateral 
 ligament. 5. The coronary ligament. 
 6. The insertion of the coronary liga- 
 ment at the posterior part of the lesser 
 sigmoid cavity of the ulna. 7. The an- 
 terior ligament. 8. The posterior liga- 
 ment. 9. The interosseous ligament of 
 the forearm. 
 
 The POSTERIOR LIGAMENT, Fig. 123 (s), consists of but 
 little more than condensed areolar tissue. The fibres which 
 it contains pass in different directions between the humerus 
 and the ulna. 
 
 The ANNULAR or ORBICULAR LIGAMENT, Fig. 122 (3), sur- 
 rounds the cervix of the radius. It is attached to the extre- 
 mities of the small sigmoid cavity of the ulna. The synovial 
 membrane is prolonged from the upper part of the joint 
 
THE ELBOW-JOINT. 283 
 
 downwards between this ligament and the cervix. Thus the 
 cervix of the radius, as well as the head, it will be observed, 
 is covered with synovial membrane. This should be noticed 
 with reference to the occurrence of fracture in this part of the 
 radius. 
 
 The BOUND or OBLIQUE LIGAMENT, Fig. 122 (4), consists 
 of a small fasciculus, which extends from the coronoid pro- 
 cess obliquely downwards, to be inserted into the radius, just 
 below its tubercle. 
 
 The INTEROSSEOUS LIGAMENT or MEMBRANE, Fig. 122 (5), 
 is composed of fibres which extend from the inner border of 
 the shaft of the radius obliquely downwards to the opposite 
 border of the ulna. It gives attachment on both of its sur- 
 faces to muscles, and is perforated for the passage of vessels 
 and nerves. 
 
 The radius and ulna, at their inferior extremities, are con- 
 nected to each other by a FIBRO-CARTILAGE, Fig. 125 (s), 
 which extends from the styloid process of the ulna to the 
 inner border of the radius, between its carpal and ulnar arti- 
 cular surfaces. The anterior and posterior borders of this 
 fibro-cartilage are attached to the radio-carpal ligaments. 
 The synovial membrane between the radius and ulna is 
 sometimes called the sacciform membrane or ligament, Fig. 
 125(i). It is strengthened by anterior and posterior fibres, 
 which pass from one bone to the other. 
 
 The radius and ulna are joined to the carpus by an ex- 
 ternal and an internal lateral, and an anterior and a posterior 
 ligament. 
 
 The EXTERNAL LATERAL LIGAMENT, Fig. 124 (4), arises 
 from the styloid process of the radius, and is inserted into 
 the scaphoides and trapezium, and the annular ligament. 
 
 The INTERNAL LATERAL LIGAMENT, Fig. 124 (5), arises 
 from the styloid process of the ulna, and is inserted into 
 the cuneiform and pisiform bones. 
 
 The ANTERIOR LIGAMENT, Fig. 124 (3), arises from the 
 anterior border of the lower end of the radius, and from the 
 ulna, and is inserted into the scaphoid, semilunar, and cunei- 
 form bones. 
 
 The POSTERIOR LIGAMENT arises from the radius and ulna 
 
284 
 
 THE UPPER EXTREMITY. 
 
 behind, and is inserted into the semilunar and cuneiform 
 bones. 
 
 Fig. 124. 
 
 THE LIGAMENTS OP THE ANTERIOR ASPECT OP 
 THE WRIST AND HAND. 1. The lower part of the 
 interosseous membrane. 2. The anterior inferior 
 radio-ulnar ligament. 3. The anterior ligament of 
 the wrist joint. 4. Its external lateral ligament. 
 5. Its internal lateral ligament. 6. The palmar 
 ligaments of the carpus. 7. The pisiform bone 
 with its ligaments. 8. The ligaments connecting 
 the second range of carpal bones with the meta- 
 carpal and the metacarpal with each other. 9. 
 The capsular ligament of the carpo-metacarpal 
 articulation of the thumb. 10. Anterior ligament 
 of the metacarpo-phalangeal articulation of the 
 thumb. 11. One of the lateral ligaments of that 
 articulation. 12. Anterior ligament of the meta- 
 carpo-phalangeal articulation of the index finger; 
 this ligament has been removed in the other 
 fingers. 13. Lateral ligaments of the same articu- 
 lation ; the corresponding ligaments are seen in 
 the other articulations. 14. Transverse ligament 
 connecting the heads of the metacarpal bones of 
 the index and middle fingers ; the same ligament 
 is seen between the other fingers. 15. Anterior 
 and one lateral ligament of the phalangeal articu- 
 lation of the thumb. 16, 16. Anterior and lateral 
 ligaments of the phalangeal articulations of the 
 index finger; the anterior ligaments are removed 
 in the other fingers. 
 
 The carpus is composed of eight bones, arranged in two 
 rows; there being four in each row. The bones in the upper 
 row, except the pisiform, are connected together by two 
 dorsal and two palinar transverse ligaments, and also by two 
 interosseous fibro-cartilages. The pisiform is connected by a 
 capsular ligament to the cuneiform, and by ligamentous fibres 
 to the unciform and fifth metacarpal bone. The bones of the 
 lower row are joined together by three dorsal, and three palmar 
 transverse ligaments, and two interosseous fibro-cartilages. 
 
 The two rows are connected to each other by dorsal and 
 palmar, and external and internal lateral ligaments. The dor- 
 sal and palmar ligaments consist of fibres which pass ob- 
 liquely from the bones of one row to those of the other. 
 
 The external lateral ligament extends from the scaphoid to 
 the trapezium. The internal lateral ligament connects the 
 cuneiform and unciform bones. 
 
THE LIGAMENTS OF THE HAND. 
 
 285 
 
 The trapezium is connected to the metacarpal bone of the 
 thumb by a capsular ligament. This articulation allows to 
 
 Fig. 125. 
 
 A DlAGKAM SHOWING THE DISPOSITION 
 OP THE FIVE SYNOVIAL MEMBRANES OF 
 THE WRIST-JOINT. 1. The sacciform mem- 
 brane. 2. The second synovial membrane. 
 3, 3. The third, or large synovial mem- 
 brane. 4. The synovial membrane between 
 the pisiform bone and the cuneiform. 5. 
 The synovial membrane of the metacarpal 
 articulation of the thumb. 6. The lower 
 extremity of the radius. 7. The lower 
 extremity of the ulna. 8. The inter- 
 articular fibro cartilage, s. The scaphoid 
 bone. L. The semilunar. c.- The cunei- 
 form ; the interosseous ligaments are seen 
 passing between these three bones and 
 separating the articulations of the wrist 
 (2) from the articulation of the carpal 
 bones (3). P. The pisiforme. T. The 
 trapezium. 2T. The trapezoides. ir. The 
 os magnum, u. The unciforrn interos- 
 seous ligaments are seen connecting the 
 os magnum with the trapezoides and unci- 
 form. 9. The base of the metacarpal bone 
 of the thumb. 10, 10. The bases of the 
 other metacarpal bones. 
 
 the thumb a great degree of motion. The metacarpal bones 
 of the fingers are connected to the carpus by dorsal and pal- 
 mar ligaments. The former are stronger than the latter. 
 
 The metacarpal bones are united at their carpal extremi- 
 ties by dorsal and palmar transverse ligaments, and also by 
 interosseous fibres. Their phalangeal extremities are connected 
 to each other by three loose transverse fibrous bands. 
 
 Each metacarpal bone is connected to its corresponding 
 phalangeal bone by an anterior and two lateral ligaments. 
 The anterior ligament is joined to-the lateral ligaments on its 
 sides. Anteriorly it is grooved for the tendons of the flexor 
 muscles of the fingers, the sheaths of which are attached 
 to it on each side of the groove. The lateral ligaments of 
 the thumb are very strong, and sometimes contain sesamoid 
 bones. 
 
 The articulations of the phalangeal bones have each an 
 anterior and two lateral ligaments. They require no particular 
 description. 
 
 The synovial membranes, Fig. 125, about the wrist should 
 be carefully examined. There are five distinct capsules. 
 
286 DISSECTION OF SPINAL CANAL AND CONTENTS. 
 
 The large extent of articular surface in the carpus, is deser- 
 ving of notice. The different joints should be opened by the 
 student. This can be done after the soft parts have been 
 dissected, without injuring the bones. 
 
 SECT. Y. DISSECTION OF THE SPINAL CANAL AND ITS 
 CONTENTS. 
 
 To lay open the spinal canal, the soft parts which cover the 
 lamellae of the vertebrae should be entirely removed. When 
 this has been done, a mallet and sharp chisel may be used 
 for dividing the lamellae on each side of the spinous processes ; 
 or, instead of the chisel, a saw may be used for this purpose. 
 Bone-nippers will also sometimes be found useful. The liga- 
 mentous attachments must be severed with the scalpel. The 
 vertebral column should be made as convex, posteriorly, as 
 possible, by placing blocks underneath the subject. If the 
 calvaria and the posterior part of the occipital bone have 
 been removed before opening the canal, the student will be 
 able to obtain a very satisfactory view of the relations of the 
 parts in the spinal canal to those in the cranial cavity. 
 
 The contents of the spinal canal are the following : The 
 dura mater, the arachnoid, the pia mater, the spinal cord, 
 the roots of the spinal nerves, the spinal ganglia, and the 
 intra-spinal vessels. 
 
 The DUEA MATER of the cord has the same structure as 
 that of the brain, with which it is continuous through the 
 occipital foramen; it has not, however, the same uses. It 
 does not form an internal periosteum to the walls of the 
 spinal canal, nor does it furnish sinuses for the transmission 
 of venous blood, or send off processes to support different 
 parts of the spinal marrow. 
 
 It is separated from the parietes of the canal, more or less, 
 by a soft, reddish, adipose and areolar tissue, and by plexuses 
 of veins. It has fibrous attachments to the posterior common 
 spinal ligament. Its external surface is generally smooth. 
 In size it corresponds to the cord, being larger in the neck 
 and the loins than elsewhere. It gives off processes, which 
 surround the nerves as they pass through the intervertebral 
 foramina. The lower part of it is divided into tubular pro- 
 
SPINAL CANAL AND CONTENTS. 287 
 
 longations, which contain the sacral nerves as they extend 
 some distance in the canal before leaving it. Below it sends 
 down a small fibrous cord, which is attached to the walls of 
 the lower part of the sacral canal. It is more fixed in the 
 anterior than in the posterior part of the canal, by its attach- 
 ments to the posterior common spinal ligament. 
 
 The AEACHNOID lines the internal surface of the dura 
 mater, and also invests the cord. It is exposed by slitting 
 open the dura mater in the median line, through its whole 
 length. It is continuous with the arachnoid of the brain, 
 to which it is similar in structure and function. The 
 visceral portion is connected to the parietal by tubular pro- 
 longations around the roots of the nerves. 
 
 It is separated from the pia mater by the sularachnoid 
 space, which is occupied by cellulo-fibrous tissue and a fluid. 
 The fibrous structure is most abundant in the middle line 
 behind, where it forms an imperfect septum. If this space be 
 punctured in a living animal, the subarachnoid fluid escapes 
 in a jet, causing, for a time, stupefaction of the animal. The 
 principal use of this fluid is, probably, to protect the spinal 
 marrow. A serous exhalation takes place from both surfaces 
 of the arachnoid membrane, where it invests the cord. 
 
 The PIA MATEE surrounds and adheres closely to the 
 spinal cord. It is continuous with that of the brain, from 
 which, however, it differs in structure, being more dense and 
 fibrous, and less vascular. It sends prolongations into the 
 anterior and posterior fissures of the cord, and also along the 
 roots of the nerves. It terminates below, after furnishing 
 sheaths for the nerves, in a fibrous cord, which descends to 
 the sacrum, where it is attached to the dura mater. 
 
 The LIGAMENTUM DENTicuLATUM, Fig. 126 (i 9), is found on 
 each side of the cord, and between the anterior and posterior 
 roots of the nerves ; it reaches from the occipital foramen to 
 the first lumbar vertebra. Its inner border is straight, and 
 appears to be blended with the pia mater ; while its outer 
 border presents a series of tooth-like processes, which are 
 attached to the dura mater in the spaces between the foramina 
 which give exit to the nerves. In the upper part of the 
 canal the spinal accessory nerve lies behind it. The serrated 
 processes number twenty one or two. It separates the roots 
 of the nerves and prevents lateral movement of the cord. 
 
288 DISSECTION OF SPINAL CANAL AND CONTENTS. 
 
 The intra-spinal vessels consist of those which supply the 
 walls of the canal, and the cord, including its 
 Fig. 126. membranes. 
 
 Xl[n The ARTEEIES are derived from the verte- 
 
 bral, the intercostal, the lumbar, and the lateral 
 sacral. Those which are denominated the an- 
 terior and posterior spinal arteries arise from the 
 vertebral near the occipital foramen. There 
 are two posterior and one anterior. They sup- 
 ply, principally, the upper part of the cord. 
 The remaining arteries enter the canal through 
 the intervertebral foramina, and reach the cord 
 by passing along the roots of the nerves. 
 There are usually three or four branches much 
 larger than the others. These form a free 
 anastomosis with the anterior and posterior 
 spinal arteries. 
 
 The YEINS of the cord leave the canal by 
 passing through the occipital and interverte- 
 bral foramina. Those which enter the cranial 
 cavity terminate in the sinuses of the dura 
 mater ; the others are connected with the sacral, 
 the lumbar, the intercostal, and the vertebral 
 veins. There are several plexuses of veins in 
 the spinal canal outside of the dura mater. 
 These are designated the anterior, the lateral, 
 and the posterior plexuses. There are two 
 plexuses which extend the whole length of the 
 canal. They are situated on the posterior sur- 
 face of the bodies of the vertebras, one on each 
 side of the posterior common ligament. These 
 plexuses all communicate freely with each 
 other. 
 
 AN ANTERIOR VIEW OF THE SPINAL MARROW, SEEN IN ITS WHOLE LENGTH, AFTER 
 REMOVAL FROM THE SPINAL CANAL. 1. Lines indicating the corpora pyramidalia. 
 2. Corpora olivaria. 3. Anterior face of the spinal marrow. 4. Anterior roots of 
 the cervical spinal nerves. 5. Anterior roots of the dorsal nerves. 6. Anterior 
 roots of the lumbar nerves. 7. Anterior roots of the sacral nerves. 8, 9, 10, 11. 
 The anterior and posterior roots of the spinal nerves, united to pass out of the dura 
 mater. 12. Dura mater of the medulla spinalis. 13. Ganglia on the cervical 
 nerves. 14. Ganglia on the dorsal nerves. 15. Ganglia on the lumbar nerves. 16. 
 Ganglia on the sacral nerves. 17. Cauda equina. 18. Sub-occipital nerve. 19. 
 Ligamenturn denticulatuin. 
 
DISSECTION OF SPINAL CANAL AND CONTENTS. 289 
 
 Fig. 127. 
 
 THE MEDULLA SPINALIS, OK SPINAL CORD. 
 
 The spinal cord, Fig. 126, extends from the occipito- 
 atlantoid articulation, to the first lumbar vertebra; being 
 from sixteen to eighteen inches in length. It is much smaller 
 than the spinal canal. It is not of equal size throughout its 
 whole length. Those portions which correspond to the roots 
 of the nerves that supply the upper and lower extremities, 
 are the largest. It terminates below in the cauda equina, Fig. 
 126 (17), which consists of nervous cords. 
 
 The cord presents, externally, an anterior and a posterior 
 median fissure, Fig. 128, which 
 divide it, externally, into two 
 distinct lateral columns. The 
 pia mater enters these fissures. 
 The anterior one is the widest, 
 while the posterior is the 
 deepest. A lateral fissure is 
 observed where the posterior 
 roots of the nerves are attach- 
 ed to the cord. This fissure 
 divides each half of the cord 
 into an antero-lateral, and a 
 posterior column. Another 
 lateral fissure has been de- 
 scribed, corresponding to the 
 anterior roots of the nerves; 
 this, however, is scarcely per- 
 ceptible. 
 
 When a transverse section 
 
 of the cord is made, each half is seen to consist, internally, of 
 gray substance, Fig. 128. This is arranged so as to present 
 a semilunar form, the cornua of which correspond to the 
 anterior and posterior roots of the nerves. The posterior 
 cornu reaches the external surface of the cord, but the an- 
 terior, which is the shortest and thickest of the two, does not. 
 From this arrangement of the gray substance each half of 
 the cord may be said to consist of three columns, the antero- 
 lateral being divided into two by the anterior cornu. Vesicu- 
 lar matter exists in both cornua, but is most abundant in the 
 25 
 
 A VIEW OF A SMALL PORTION OP 
 THE SPINAL MARROW, SHOWING THE 
 ORIGINS OF SOME OF THE SPINAL 
 NERVES. 1. The anterior or motor 
 root of a spinal nerve. 2. The pos- 
 terior or sensor root of a spinal 
 nerve. 3. The ganglion connected 
 with the latter. 
 
290 
 
 MEDULLA SPINALIS. 
 
 posterior. The gray substance in the anterior cornu has been 
 called the substantia gelatinosa ; and that in the posterior, the 
 substantia spongiosa. 
 
 The two halves of the cord are united by a gray commissure 
 at the bottom of the posterior median fis- 
 J ^'^ ' sure, and a white commissure at the bottom 
 
 of the anterior median fissure. 
 
 The relative proportions of the gray and 
 white substance vary somewhat in differ- 
 ent sections of the cord. 
 
 The precise manner in which the spinal 
 nerves are connected with the substance 
 of the cord, is not well understood. The 
 anterior and posterior roots approach each 
 other as they proceed from the cord to the 
 foramina in the dura mater, Fig. 126 (s, 9, 
 10, 11), through which they pass sepa- 
 rately. The posterior root or fasciculus of 
 each nerve enters a ganglion, Fig. 127 (3), 
 in the intervertebral foramen ; and almost 
 immediately after passing through the 
 ganglion it joins the anterior fasciculus, 
 and is inclosed with it in the same neuri- 
 lemma, which is derived from the dura 
 mater. The fasciculi increase in length 
 from above downwards before they per- 
 forate the fibrous sheath of the cord. 
 
 The posterior roots are sensor, and are 
 larger than the anterior, which are motor, 
 Fig. 127 (i, 2). Each set is supposed to 
 contain filaments, which belong to both 
 J 3 the excito-motor and the cerebro-spinal 
 
 F TSliL system of nerves. 
 
 ff. 
 
 TRANSVERSE SECTION OP THE SPINAL CORD. A. Immediately below the decussa- 
 tion of the pyramids. B. At middle of cervical bulb. c. Midway between cervical 
 and lumbar bulbs. D. Lumbar bulb. E. An inch lower. F. Very near the lower 
 end. a. Anterior surface, p. Posterior surface. The points of emergence of the 
 anterior and posterior roots of the nerves are also seen. 
 
DISSECTION OF THE THORAX. 291 
 
 CHAPTER II. 
 
 SECT. I. DISSECTION OF THE THORAX. 
 
 THE thorax is situated between the neck above, the abdo- 
 men below, and the upper extremities laterally. The solid 
 parietes of the thoracic cavity consist of the sternum and 
 costal cartilages in front, of the ribs laterally, and the dorsal 
 vertebrae, with the posterior extremities of the ribs behind. 
 
 The shape of the thorax is that of a truncated cone, indented 
 behind by the spinal fossae. Its base is oblique, sloping from 
 the xiphoid cartilage downwards and backwards to the first 
 lumbar vertebra. Its apex is also oblique, but from before 
 upwards and backwards to the last cervical vertebra; hence 
 the vertical diameter of the thoracic cavity is much greater 
 behind than before. 
 
 The spaces between the ribs are occupied by aponeurosis 
 and the intercostal muscles, which are perforated by branches 
 of the intercostal arteries and nerves, and by branches of the 
 internal mammary arteries. 
 
 The upper orifice of the thoracic cavity is broader trans- 
 versely than from behind forwards. Its boundaries are 
 formed, in front, by the upper border of the sternum, on each 
 side by the first rib, and behind, by the first dorsal vertebra. 
 
 It transmits the oesophagus, the trachea, the thoracic duct, 
 the pneumogastric, phrenic, and sympathetic nerves, and 
 the large arteries and veins of the head, neck, and upper 
 extremities ; the superior intercostal and internal mammary 
 arteries, with the recurrent laryngeal nerves, also pass through 
 it. Besides the parts just enumerated, and the thoracic fascia, 
 which surrounds and connects them together, the apex of each 
 lung, with the pleura and several muscles, are included in 
 this opening. 
 
 The lower orifice is four or five times larger than the upper, 
 and is liable to much greater variation in size. It is bounded 
 in front by the xiphoid cartilage, laterally by the lower six 
 
292 DISSECTION OF THE THORAX. 
 
 ribs and their cartilages, and behind, by the last dorsal vertebra. 
 Its circumference embraces the upper abdominal viscera, as 
 the liver, the stomach, the spleen, &c. The diaphragm, which 
 forms the septum between the abdominal and thoracic cavi- 
 ties, is attached to nearly the whole of its margin. The oeso- 
 phagus, the thoracic duct, the pneumogastric, sympathetic, 
 and splanchnic nerves, the aorta, the ascending vena cava, 
 and the azygos vein, pass through the diaphragm. 
 
 The intercostal muscles should be examined before the 
 cavity of the thorax is opened. They consist of two sets, 
 the internal and external. 
 
 The EXTERNAL INTERCOSTALS, Fig. 147 (4), extend from 
 the vertebral articulations of the ribs to the costal cartilages. 
 They arise from the outer lip of the lower border of each 
 rib, except the last, pass obliquely downwards and for- 
 wards, and are inserted into the corresponding lip of the 
 upper border of each rib, immediately below their origin. 
 
 The INTERNAL INTERCOSTALS, Fig. 147 (5), extend from the 
 angles of the ribs to the sternum. They arise from the inner 
 lip of the lower border of each rib and its cartilage, except 
 the last, pass downwards and somewhat backwards, and 
 are inserted into the upper border of each rib, below their 
 origin. An aponeurosis extends from the external to the ster- 
 num, and also from the internal to the costo-vertebral articu- 
 lations. A considerable portion of each of the intercostal 
 muscles is tendinous, or aponeurotic. Their fibres have the 
 same direction, respectively, as those of the external and in- 
 ternal oblique muscles of the abdomen. The intercostal arte- 
 ries and nerves pass between them. They act as muscles of 
 inspiration or expiration, according as the first rib, or the 
 lower ribs be fixed. The crossing of them adds to the strength 
 of the thoracic parietes. 
 
 The cavity of the thorax may now be opened for the study 
 of its contents. This may be done in several ways. If it be 
 wished to preserve the skeleton, the student can obtain a very 
 good idea of the thoracic viscera and heir relations by adopt- 
 ing the following method : 
 
 Saw through the sternum in the median line, taking care 
 not to injure the soft parts underneath it. Then divide the 
 intercostal muscles, and separate the costal cartilages, on each 
 
THE THORAX. 293 
 
 side, from the ribs ; the pleura may be divided at the same 
 time, as this will not interfere with the study of it afterwards. 1 
 By carefully separating the two halves of the sternum, a 
 space will be observed behind it, bounded laterally by the 
 pleurae ; and, by raising the cartilages on each side, the man- 
 ner in which this space is formed will be readily understood, 
 by observing that each pleura is reflected from the posterior 
 surface of the sternum backwards. It will be noticed that, 
 as the pleurae leave the sternum, they are,4n the centre, very 
 nearly in apposition, leaving scarcely any space between them, 
 while above and below they are separated a short distance 
 from each other. The left pleura is reflected from the lower 
 part of the sternum obliquely downwards, and to the left 
 side. 
 
 One half of the sternum, with the cartilages attached to it, 
 may now be raised, commencing at its upper extremity, and 
 reflected downwards over the abdomen without detaching it 
 from the diaphragm. In raising it, the origin of the sterno- 
 thyroideus, and sometimes that of the sterno-hyoideus, the 
 internal mammary artery, the triangularis sterni muscle, and 
 the intercostal nerves, will be seen. 
 
 The TRIANGULARIS STERNI MUSCLE is situated behind the 
 sternum and costal cartilages. It arises from the side of the 
 sternum and xiphoid cartilage, and some of the costal carti- 
 lages close to the sternum. It divides into several digitations, 
 which are inserted into the second, third, fourth, fifth, and 
 sixth ribs. The lower fibres have nearly a transverse direc- 
 tion, and are continuous with the transverse muscle of the 
 abdomen ; the upper fibres pass obliquely upwards and out- 
 wards. Its action is to draw down, or to fix the costal carti- 
 
 The INTERNAL MAMMARY ARTERY arises from the sub- 
 clavian opposite to the supra-scapular, and passes obliquely 
 downwards behind the sternal extremity of the clavicle and 
 cartilage of the first rib, where it enters the cavity of the 
 
 1 A partial view of the contents of the thoracic viscera may be obtained 
 by simply dividing the sternum in the median line, and separating the two 
 halves by means of dilators made for the purpose, or by any means which 
 may be most convenient. To make a thorough examination of the contents 
 of the thoracic cavity, it is necessary to cut away, more or less, the ribs. 
 
 25* 
 
294 DISSECTION OF THE THORAX. 
 
 thorax. In this part of its course, the phrenic nerve crosses 
 it superficially from without inwards. Its course in the thorax 
 is nearly parallel with, and about one-third of an inch from, 
 the border of the sternum. It is situated between the costal 
 cartilages in front and the pleura and triangularis sterni mus- 
 cle behind. At the sixth intercostal space it divides into two 
 branches, external and internal. 
 
 The internal division, which is generally-regarded as a con- 
 tinuation of the artery, passes beneath the cartilage of the 
 seventh rib, and pierces the sheath of the rectus abdominis 
 muscle. It supplies the upper and anterior parietes of the 
 abdomen, and inosculates with branches of the epigastric, thus 
 connecting the external iliac and subclavian arteries. 
 
 The external branch, or musculo-phrenic, goes obliquely 
 downwards and outwards to the eleventh intercostal space, 
 giving off, in its course, branches to the diaphragm, and to 
 the intercostal and abdominal muscles. Its branches inoscu- 
 late, with the lower intercostal arteries, from the aorta. 
 
 The internal mammary artery, before it divides, gives off 
 the following branches : 
 
 The anterior intercostals are directed outwards, in the inter- 
 costal spaces ; they inosculate with the aortic intercostals. 
 There are frequently two in each space. 
 
 The anterior, or perforating branches, pierce the internal in- 
 tercostal and pectoralis major muscles. They are distributed 
 to these muscles, and to the integuments and mammary gland, 
 and inosculate with branches from the axillary artery. 
 
 The mediastinal branches are distributed to the remains of 
 the thymus gland, and other parts in the mediastinal space. 
 
 A branch comes nervi phrenici accompanies the phrenic 
 nerve to the diaphragm, giving branches in its course to the 
 pericardium. The internal mammary artery has two vence 
 comites. 
 
 The ANTERIOR CUTANEOUS BRANCHES of the upper inter- 
 costal nerves may be seen where they perforate the internal 
 intercostal and pectoralis major muscles near the sternum, to 
 reach the integument. 
 
 There are three serous sacs in the thoracic cavity one for 
 each lung, and one for the heart. The necessity of each of 
 these organs having appropriated to it a serous membrane 
 
THE PLEUEA. 295 
 
 will be understood when it is considered that they are sub- 
 jected to more or less motion. Each sac is divided into a 
 visceral and a parietal portion. The first is applied closely 
 to the external surface of the organ, while the other lines 
 the inner surface of the cavity which contains it. Thus two 
 smooth surfaces are opposed to each other, which are con- 
 stantly lubricated with serum, so that no friction is caused 
 by their movements upon each other. 
 
 THE PLEUKA. 
 
 The student should now carefully trace the reflections of 
 the pleura for himself, and observe its relations to the con- 
 tiguous parts, and to the external surface of the body. The 
 pleural cavity has been exposed by separating the costal car- 
 tilages from the ribs, and raising them on one side with the 
 corresponding half of the sternum. It will be observed 
 that as the pleura is reflected from the posterior surface of 
 the sternum, it proceeds almost directly backwards to the 
 vertebral column. 
 
 The corresponding portions of the two pleura3 form a sep- 
 tum between the pleural cavities, called the mediastinum. The 
 lower part of this septum is inclined somewhat to the left 
 side on account of the position of the heart. That portion 
 of each pleura concerned in forming the mediastinum is 
 called the pleura mediastinalis. As this is traced from the 
 sternum backwards, it will be found in the upper part of the 
 thorax to pass almost directly to the vertebra, while in the 
 middle and lower parts it is reflected outwards over the 
 pericardium, to which it closely adheres, except where it 
 covers the phrenic nerve. As it proceeds backwards it is, 
 near the middle of the mediastinum, reflected round the root 
 of the lung, from which it is extended over the entire lung, 
 forming the pleura pulmonalis. 
 
 In the lower part it forms a fold extending from the root 
 of the lung to the diaphragm, called the ligamentum latum 
 pulmonis. This fold is of a triangular shape, with the apex 
 towards the root of the lung. If the lungs be drawn for- 
 wards it will be seen that the pleurae approach each other as 
 
296 DISSECTION OF THE THOEAX. 
 
 they are reflected from the roots of the lungs and the peri- 
 cardium to the vertebral column. 
 
 The pleura mediastinalis is continuous below, with the 
 pleura diaphragmatic^ and laterally with the pleura costalis. 
 The former lines the thoracic surface of the diaphragm ; the 
 latter covers the inner surface of the ribs and intercostal 
 spaces, the internal mammary and intercostal arteries, the 
 splanchnic, sympathetic and intercostal nerves, and the dor- 
 sal ganglia of the sympathetic. 
 
 The pleura is prolonged from half an inch to an inch above 
 the first rib, where it covers the posterior surface of the lower 
 part of the scalenus anticus muscle, and the subclavian artery. 
 It usually extends somewhat higher on the right side than 
 on the left. Small masses of fat, similar to the appendices 
 epiploicas on the colon, are sometimes observed on the medias- 
 tinal and diaphragmatic portions. 
 
 The pleura pulmonalis lines the fissures which separate the 
 lobes of the lung. It is very thin and elastic. The inner or 
 fibrous layer is connected with the parenchyma of the lung. 
 The air will generally escape through it from the cells when 
 the lungs are removed from the thorax and inflated. The 
 fibrous layer of the costal pleura is thicker than that of either 
 of the other portions, and more easily detached from the 
 subjacent tissues. 
 
 The shape of the cavity formed by the parietal pleura is 
 the same as that of the lung which fills it. The left one is 
 longer than the right, but not so broad. Abscesses rarely 
 open into the pleural cavities, either from the lungs or from 
 the surrounding parts. 
 
 Having examined the pleura, the student should now pro- 
 ceed to the study of the contents of the mediastinal space. 
 
 The boundaries of this space are on each side the medias- 
 tinal pleura, in front the sternum, behind the vertebral 
 column, below the diaphragm, and above the upper orifice of 
 the thorax. To facilitate the study of the organs, especially 
 of their position in the thorax, contained in this space, it 
 will be found convenient to divide it into four parts ; and as 
 the heart is the principal organ in point of size in it, it 
 naturally forms the basis of this division. 
 
 Observing its position, or that of the pericardium, the 
 student will have no difficulty in understanding these di- 
 visions. 
 
THE PLEURA. 
 
 297 
 
 The anterior is situated between the heart and the ster- 
 num ; the posterior between the heart and the spinal 
 column; the superior, between the heart below, and the 
 upper orifice of the thorax above, the sternum in front, and 
 the spinal column behind; while the heart and" pericar- 
 dium occupy the middle. The mediastinal pleuraa form 
 the lateral boundaries of each of these divisions. Thus 
 it will be seen that while the heart is below the supe- 
 rior mediastinum, and in the middle, it is directly between 
 the anterior and posterior mediastina, as they are usually 
 termed. The diagram, Fig. 129, representing a section of 
 the thorax in the median line, shows 
 the relative position of the four sub- 
 divisions of the mediastinal space. 
 
 The anterior mediastinum has been 
 exposed by the longitudinal section, 
 and removal of the sternum. It con- 
 tains the lower portion of the remains 
 of the thymus gland, areolar tissue, 
 and some fat. As the diaphragm is 
 deficient behind the xiphoid cartilage, 
 this space is separated from the cavity 
 of the abdomen only by areolar tissue, 
 which accounts for pus sometimes 
 passing from it into that cavity. The 
 cavity of the pericardium can be 
 reached, as in paracentesis pericardii, 
 through this space, without opening 
 either of the pleural cavities. 
 
 DIAGRAM OF.THE THORACIC 
 MEDIASTINA. a, 6. Dorsal 
 vertebrae, c. Sternum. d. 
 Diaphragm, or lower orifice of 
 the thorax, e. Upper orifice of 
 the thorax. 1. Anterior medi- 
 astinum. 2. Middle mediasti- 
 num ; figure is on the heart. 
 3. Posterior mediastinum. 4. 
 Superior mediastinum. 
 
 The PHRENIC NERVES should be 
 noticed before examining the pericar- 
 dium. They will be found passing 
 through the middle mediastinum, from 
 above downwards on the sides of the pericardium, between 
 it and the pleura. They can usually be distinctly seen with- 
 out dissecting off the pleura. The left is somewhat longer 
 than the right, on account of the projection of the pericar- 
 dium to the left side. They descend to the diaphragm, and 
 ramify on its upper surface, between it and the pleurae ; some 
 filaments pass through the muscle, and ramify on its abdo- 
 
298 DISSECTION OF THE THORAX. 
 
 minal surface, where an anastomosis is formed between the 
 two nerves. They are said, also, to anastomose with the 
 pneumogastric nerve and solar plexus. 
 
 THE PERICARDIUM. 
 
 The PERICARDIUM is a fibro-serous membrane, which sur- 
 rounds the heart. To obtain a good view of it, the areolar 
 tissue, and fat in the anterior mediastinum should be removed. 
 It will be found to have a conical form, with the base down- 
 wards, and the apex upwards. The base is closely connected 
 anteriorly, to the cordiform tendon of the diaphragm, from 
 which it cannot, without difficulty, especially in the adult, be 
 separated. In consequence of this attachment, but little 
 motion is allowed to the lower part of the pericardium. The 
 apex terminates above by being blended with the thoracic 
 fascia, the external layers of the vena cava, aorta, and pulmo- 
 nary artery, some distance from the base of the heart. Late- 
 rally it is in relation with the pleurae and phrenic nerves. In 
 front it corresponds to the sternum, and the cartilages of the 
 fifth, sixth, and seventh ribs, from which it is separated by the 
 anterior mediastinum and the pleuras, and the left lung, which 
 is excavated for the reception of the heart. Posteriorly it 
 forms the anterior wall of the posterior mediastinum. 
 
 Its fibrous or external lamina is perforated by all the 
 large vessels which leave or enter the heart. These are the 
 two venas cavse, the aorta, the pulmonary artery, and the four 
 pulmonary veins. 
 
 The pericardium may now be opened by making a longi- 
 tudinal, and, if necessary, a transverse incision. The inner 
 or serous layer presents the same appearance as other serous 
 membranes. It lines the internal surface of the fibrous layer, 
 and is reflected from it upon the large vessels at the base 
 of the heart, and from them over the heart itself. 
 
 It is reflected from the fibrous layer to the vessels, where 
 that layer joins their outer coats. This takes place upon the 
 vena cava descendens, near the entrance of the vena azygos. 
 At first it is limited to the anterior surface of this vessel, but 
 nearly surrounds it at the auricle. It is reflected to the aorta 
 at its arch, and to the pulmonary artery at its bifurcation ; 
 and, as it descends to the ventricles, it completely invests 
 
THE HEART. 299 
 
 those vessels, except where they are in apposition. It covers 
 anteriorly the pulmonary veins between the left auricle and 
 their divisions into branches. The vena cava ascendens is 
 only partly invested by it. Where it is reflected over the 
 vessels, it forms between them depressions or culs-de-sac. 
 
 When the heart is empty, it lies loosely in the cavity of 
 the pericardium, but when the former is full, or distended, it 
 just fills the latter. When the blood escapes from the cavities 
 of the heart, or from the great vessels at its base into the 
 pericardium, it destroys life by interfering mechanically with 
 the action of the heart. 
 
 The fibrous layer of the pericardium is composed of fibres 
 crossing in different directions ; a large proportion of them, 
 however, are longitudinal. This membrane is very strong 
 and slightly elastic. Although the heart, when distended, 
 just fills the pericar^um, yet the latter is sometimes in- 
 creased to two or three times the size of the former, by the 
 gradual accumulation of fluid in it. 
 
 The student should observe the effect such a collection 
 would have by making pressure upon, or by causing dis- 
 placement of, surrounding organs. Fat is not unfrequently 
 deposited in considerable quantity between the muscular 
 fibres of the heart and the serous layer which invests it. 
 
 THE HEAKT. 
 
 It is better that the student should examine the heart be- 
 fore it is removed from the thorax ; or, at least, the more 
 important parts of it. Before proceeding to its dissection, he 
 should carefully observe its position in the thoracic cavity, 
 its relations to contiguous parts, its external appearance, and 
 the situation of its different compartments, the auricles and 
 ventricles. 
 
 It is situated, as will be seen, in the lower and central 
 part of the thorax, between the lungs, and resting on the 
 diaphragm. Its form is conical, presenting a base, body, and 
 apex. The base looks upwards, backwards, and to the right 
 side ; it corresponds, in front, to an oblique line extending 
 across the sternum from the third intercostal space on the 
 left side to the fourth and fifth on the right side ; and behind, 
 to the fifth, sixth, and seventh dorsal vertebrae, from which it 
 
300 DISSECTION OF THE THORAX. 
 
 is separated by the contents of the posterior mediastinum. 
 The apex looks forwards and to the left side ; being nearly 
 opposite to the junction of the sixth rib with its cartilage. 
 The axis of the heart has a direction from right to left, from 
 above downwards, and from behind forwards. 
 
 Before displacing the heart, the following points should be 
 carefully observed : 
 
 The three great vessels, vena cava descendens, aorta, and 
 pulmonary artery, will be seen at its base. The vena cava, 
 Fig. 130 (s), descends on the right side to enter the upper 
 part of the right auricle. The pulmonary artery, Fig. 130 
 (is), prominent at its commencement, ascends from the su- 
 perior and left portion of the right ventricle. The aorta, 
 Fig. 130 (e), at first deep seated and partly concealed by the 
 pulmonary artery, ascends between the_other two. The right 
 auricle, Fig. 130 (i), is applied to the aorta, and the left auricle 
 Fig. 130 (2), to the pulmonary artery. Only a small portion 
 of the left auricle can be seen while the heart is in situ; the 
 pulmonary artery, the aorta, and a considerable portion of the 
 right auricle being situated in front of it. 
 
 A large part of the right auricle, Fig. 130 (i), can be seen 
 without disturbing the position of the heart, of which it forms 
 the upper and right portion. It presents anteriorly, and to 
 the right, a smooth shining convex surface, which corre- 
 sponds mainly to the right lung and to the diaphragm, 
 just above which it is joined by the vena cava ascendens. 
 It is separated, superficially, from the right ventricle by a 
 groove, which is occupied by the anterior coronary artery 
 and vein, and corresponds to the auriculo-ventricular septum. 
 
 The right ventricle, Fig. 130 (a), forms a large part of the 
 anterior surface of the heart. Its anterior surface, as now 
 seen, is convex, and of a triangular shape ; its lower border 
 rests on the diaphragm, while its superior left border is sepa- 
 rated from the left ventricle by a groove, Fig. 130 (i i), which 
 corresponds to the ventricular septum, and is occupied by 
 the posterior coronary artery and vein; its base, as has been 
 already observed, corresponds to the right auricle and the 
 pulmonary artery. A small portion of the left ventricle, Fig. 
 130 (4), is seen to the left and above the right ventricle. It 
 projects lower down than the right, and thus forms the apex 
 of the heart. 
 
THE HEART. 
 
 301 
 
 The heart should now be lifted from the pericardium so 
 as to bring into view its remaining surfaces. The inferior 
 surface of the right ventricle, Fig. 131 (3), is flat, triangular 
 and horizontal; it corresponds to the cordiform tendon of the 
 diaphragm. The posterior and left surface of the left ven- 
 tricle, Fig. 131 (4), is round, and corresponds partly to the 
 diaphragm, and partly to the posterior mediastinum and left 
 lung. The ventricles are separated behind by a groove, 
 Fig. 131 (i o), similar to the one noticed in front; it is occu- 
 pied by the posterior coronary vessels. 
 
 Fig. 130. 
 
 Fig. 131. 
 
 AN ANTERIOR VIEW OF THE HEART 
 IN A VERTICAL POSITION, WITH ITS 
 VESSELS INJECTED. 1. Right auricle. 
 2. Left auricle. 3. Right ventricle. 
 4. Left ventricle. 5. Descending vena 
 cava. 6. Aorta. 7. Left pulmonary 
 artery. 8. The arteriainnotninata. 9. 
 Left primitive carotid. 10. Left sub- 
 clayian artery. 11. Anterior cardiac 
 vessels in the vertical groove. 12. Pos- 
 terior vessels from the transverse 
 groove. 13. Main trunk of the pulmo- 
 nary artery. 
 
 A POSTERIOR VIEW OF THE HEART 
 IN A VERTICAL POSITION, WITH ITS 
 VESSELS INJECTED. 1. Right auricle. 
 2. Left auricle. 3. Right ventricle. 
 4. Left ventricle. 5. Ascending vena 
 cava. 6. Right posterior pulmonary 
 vein. 7. Left posterior pulmonary vein. 
 8. End of the left auricle. 9. Great 
 coronary vein. 10. Posterior cardiac 
 vessels in the vertical groove. 11. 
 The same in the transverse groove. 
 
 The posterior surface of the auricles, Fig. 131 (i, 2), is 
 convex, and corresponds to the posterior mediastinum ; it is 
 divided vertically by a groove, which corresponds to the au- 
 ricular septum, and is separated from the ventricles by 
 another groove, which corresponds to the auriculo-ventri- 
 cular septum. The pulmonary veins, Fig. 131 (6, 7), may 
 26 
 
302 DISSECTION OF THE THORAX. 
 
 be seen coming from the lungs, and entering the left au- 
 ricle. 1 
 
 Eeplacing the heart in the pericardium, the student should 
 now proceed to its dissection, commencing with the EIGHT 
 AURICLE. Make an incision from the vena cava descendens 
 down to the vena cava ascendens, and another transversely 
 from this to the left extremity of the auricle. The blood and 
 coagula usually found in this cavity must be removed with 
 a sponge and water. 
 
 That portion of the auricle between the mouths of the 
 vense cava3 is called the sinus venosus, while the elongated 
 portion on the left is termed the auricula, or- appendix auri- 
 culce ; from the shape of the latter the term auricle has been 
 applied to the entire cavity. The right portion of the walls 
 of the sinus seem to be formed by the junction of the venae 
 cavae, and is nearly destitute of muscular fibres. 
 
 The following are to be observed in the right auricle: 
 The tubercle of Lower, the fossa ovalis, the annulus ovalis, 
 or isthmus of Yieussens, the valve of Eustachius, the mouth 
 of the coronary vein, the valve of Thebesius, the foramina 
 of Thebesius, and the musculi pectinati. 
 
 The tubercle of Lower is a smooth rounded projection, 
 situated below and a little to the right of the mouth of the 
 descending cava. It is formed by a slight thickening of the 
 wall, and by the oblique manner in which the venae cavae 
 join the auricle. 
 
 The fossa ovalis, Fig. 132, i, is a depression situated just 
 above the mouth of the ascending cava and on the auricular 
 septum. It indicates the position of the/oraraen ovale in the 
 foetal heart, and appears to be formed by a prolongation 
 upwards of the posterior wall of the ascending cava. In the 
 upper part of this fossa a small valvular opening is frequently 
 found in the adult heart, leading into the left auricle ; from 
 its oblique direction, probably no intermixture of the blood 
 in the auricles takes place through it. 
 
 The annulus ovalis, or isthmus of Vieussens, Fig. 132, s, con- 
 sists of an elevation around the upper and left margin of the 
 fossa ovalis. In some hearts it is very imperfect. 
 
 1 The vessels of the heart cannot be very satisfactorily traced unless they 
 are injected ; and as this cannot well be done in the heart that is intended 
 for dissection, another one will be required for this purpose. 
 
THE HEART. 
 
 303 
 
 The valve of Eustachius, Fig. 132, w, is a duplicature of the 
 lining membrane of the auricle, extending upwards from the 
 anterior and inner margin of the mouth of the ascending 
 
 Fig. 132. 
 
 HEART PLACED WITH ITS ANTERIOR SURFACE UPWARDS, AND ITS APEX TURNED 
 TO THE RIGHT HAND OP THE SPECTATOR. THE RIGHT AURICLE AND RIGHT VEN- 
 TRICLE ARE BOTH OPENED. PARTS IN RIGHT AURICLE. h. Entrance of vena cava 
 superior, which is itself marked d. Inferior cava, marked r, has a probe passed 
 through it into the auricle, m. The smooth part of the auricle, o. Musculi pecti- 
 nati, seen in the auricular appendix which is cut open. n. Eustachian valve placed 
 over the mouth of the inferior cava. i. Fossa ovalis, or vestige of the foramen ovale. 
 *. Annulus ovalis. The probe leading from into the right ventricle passes through 
 the auriculo-ventricular opening, v. Mouth of the coronary vein. PARTS IN THE 
 RIGHT VENTRICLE, in which the other end of the probe, from a, appears, a. Cavity of 
 conus arteriosus, leading to the mouth of the pulmonary artery k. I. Convex sep- 
 tum between the ventricles, c. Anterior segment of the tricuspid valve connected 
 by slender chords, the chordae tendineae, to the musculi papillares e. f. The aorta. 
 
 cava, along the left border of the fossa ovalis. It performs 
 no office in the adult heart, and is often deficient, or scarcely 
 perceptible. In the foetal heart it serves to direct the blood 
 
304 DISSECTION OF THE THOEAX. 
 
 from the ascending cava into the left auricle through the 
 foramen ovale. 
 
 The mouth of the coronary vein, Fig. 132, ?;, is placed a little 
 to the left of the Eustachian valve. It is partly covered by 
 a fold of the lining membrane of the auricle, which is named 
 the valve of Thebesius. It prevents the return of the blood 
 into the vein when the auricle contracts ; its office, however, 
 cannot be very important, as it is often imperfect or wholly 
 absent. 
 
 The foramina of Thebesius are small openings, consisting of 
 the mouths of veins, or of mere crypts, in the parietes of the 
 auricle. They vary in number and in their location. 
 
 The musculi pectinati, Fig. 132, o, are muscular fasciculi, 
 which extend in parallel lines from the auricula to the 
 auriculo-ventricular orifice. They are named from their re- 
 semblance to the teeth of a comb. They are crossed by other 
 fasciculi, which cause a reticulated appearance. This reticu- 
 lated arrangement is observed especially in the auricular 
 appendix. The inner and outer membranes are in contact 
 with each other between the muscular fasciculi in some por- 
 tions of the auricle. In examining the structure of the walls 
 of the auricle it will be seen that they are not adapted to 
 exert much force in expelling the blood from the auricle into 
 the ventricle. 
 
 The interior of the EIGHT YENTEICLE should now be ex- 
 amined. For this purpose make two incisions from its apex 
 to its base, along the ventricular septum, and raise the whole 
 of its right and anterior wall without detaching it at the base. 
 To facilitate the study of the parts around the auriculo- 
 ventricular orifice, this flap may be divided through its 
 centre. 
 
 The following parts will be found in the dissection of this 
 cavity : 
 
 The columnce carnece are muscular projections on the inner 
 surface of the ventricle. They present three different kinds 
 of arrangement. The first kind are adherent to the walls 
 throughout their whole extent. The second are attached to 
 the walls at their extremities, while the middle part of each 
 is surrounded by the lining membrane of the ventricle. They 
 cross each other in different directions, so as to form a reticu- 
 lated appearance. The third set, or musculi papillares, are 
 
THE HEART. 305 
 
 few in number. They are attached, by one extremity, to the 
 walls of the ventricle, and by the other to the chordae tendi- 
 neae; they have been called the muscles of the heart. The 
 fleshy columns give to the internal surface of the ventricle 
 an irregular areolar appearance, and increase the extent of 
 the lining membrane. 
 
 The chordae tendinece are small tendinous cords which ex- 
 tend from the third set of the columnas carneae to the tricuspid 
 valve, Fig. 132, c; some of them, however, proceed directly 
 from the parietes of the ventricle to the valve. These 
 tendinous chords enter largely into the formation of the valve, 
 which they traverse in different directions ; some of them are 
 inserted into the fibrous zone which surrounds the margin of 
 the auriculo-ventricular orifice. They enable the fleshy 
 columns to which they are attached to separate, in the first 
 place, the tricuspid valve from the parietes of the ventricle, 
 and thus allow the blood to get beneath it T and when the 
 valve is forced upwards to close the opening they act as stays 
 by preventing it from being carried into the auricle. 
 
 The tricuspid valve, Fig. 132, c, consists of an annular fold 
 reflected from the margin of the auriculo-ventricular orifice 
 into the ventricle. Its free border is usually divided into 
 three segments, but sometimes into four, or even more. It 
 contains, besides the chordae tendineae, some fibrous tissue 
 which projects into it from the margin of the opening into 
 the auricle. Small fleshy masses are sometimes observed 
 attached to its free border. The largest of the three seg- 
 ments is placed between the openings into the auricle and 
 pulmonary artery. This segment may, perhaps, prevent the 
 blood from passing into the pulmonary artery during the 
 filling of the ventricle. The tricuspid valve closes the open- 
 ing between the auricle and ventricle, when the latter con- 
 tracts to force the blood into the pulmonary artery. 
 
 The auriculo-ventricular orifice is situated at the right and 
 posterior part of the base of the ventricle. It is of an ellip- 
 tical form, and is surrounded by a fibrous band or zone, to 
 which the tricuspid valve and muscular fibres in the parietes 
 of the auricle and ventricle are attached. Its antero-posterior 
 diameter is larger than the transverse. 
 
 The conus arteriosus, or infundibulum, Fig. 132, a, is a pro- 
 jection of the ventricle upwards to join the pulmonary artery. 
 It is situated at the anterior and left portion of the base. The 
 
 26* . 
 
306 DISSECTION OF THE THOKAX. 
 
 inner surface of the infundibulum is smooth, which facilitates 
 the passage of the blood from the ventricle into the pul- 
 monary artery. The term locus planus has been applied to 
 this surface. 
 
 The mouth of the pulmonary artery is situated at the upper 
 part of the infundibulum, and about three-fourths of an inch 
 from the opening into the auricle, from which it is sepa- 
 rated by a muscular elevation. It is about three-fourths of 
 an inch in diameter, is round, and surrounded by a fibrous 
 zone to which are attached muscular fibres of the walls of 
 the ventricle, the middle coat of the artery, and the semilunar 
 valves. 
 
 To examine the semilunar valves and the sinuses of Yal- 
 salva, the pulmonary artery must be slit up for an inch or 
 more from its commencement. 
 
 The semilunar, or sigmoid valves, at the mouth of the pul- 
 monary artery, are similar in appearance and structure to 
 those at the mouth of the aorta, Fig 134 (1,2, 3). They are 
 three in number. They consist of folds of the lining mem- 
 brane of the ventricle and artery, inclosing a fibrous tissue 
 similar to the middle coat of the latter. When they are de- 
 pressed and made tense, each presents a smooth convex sur- 
 face towards the ventricle, and a concave surface towards the 
 artery. In the centre of the free border of each valve is a 
 small nodule or sesamoid body, named corpus Arantii, Fig. 134, 
 c. When the valves are depressed and these small bodies are 
 brought in apposition in the centre, a perfect closure of the 
 mouth of the artery is secured. The semilunar valves, 
 although thin and apparently very delicate, are capable of 
 resisting a great deal of force. They offer no resistance to 
 the passage of the blood from the ventricle into the artery, 
 but effectually prevent its return from the latter into the 
 former. 
 
 The sinuses of Valsalva, Fig. 134, s, i, t, consist of three small 
 pouches, situated at the commencement of the pulmonary 
 artery, and, also, as will be seen, at the commencement of the 
 aorta. They are formed, by dilatations, in the coats of the 
 artery, between which and the concave surfaces of the valves 
 they are placed. They secure the closure of the valves by 
 allowing the blood to get between them and the walls of the 
 artery. They are more distinct in old than in young per- 
 sons. 
 
THE HEAKT. 
 
 307 
 
 The student should now proceed to the dissection of the 
 left side of the heart, beginning with the auricle. To reach 
 this cavity, the apex of the heart must be drawn forwards 
 and upwards. Make a vertical incision between the mouths 
 of the pulmonary veins on the right and left side, and another 
 from this into the auricula. 
 
 The LEFT AUKICLE is of a cuboidal form, especially that 
 portion which corresponds to the sinus of the right auricle. 
 It is not quite so large as the right, but has thicker and 
 stronger parietes. The appendix auriculce, Fig. 133, d, is 
 longer and more curved than that of the right auricle, but is 
 not so large. Its junction with the sinus, or larger portion, 
 is marked by a constricted orifice. The musculi pectinati 
 are found only in this part of the auricle, and are less nume- 
 rous than in the right appendix. 
 
 Fig. 133. 
 
 HEART SEEN FROM BEHIND, AND 
 HAVING THE LEFT AURICLE AND 
 VENTRICLE OPENED. PARTS IN LEFT 
 AURICLE. a. Smooth wall of auri- 
 cular septum, c, c, c. Openings of 
 the four pulmonary veins, d. Left 
 auricular appendage, e. Slight de- 
 pression in the septum, corresponding 
 to the fossa ovalis on the right side. 
 A probe is seen which passes down 
 into the ventricle through the auricu- 
 lo-ventricular orifice. PARTS IN LEFT 
 VENTRICLE. i. Posterior segment of 
 the mitral valve, behind which is the 
 probe passed from the left auricle. 
 n, n. The two groups of rnusGuli pa- 
 pillares. o. Section of the thick 
 walls of this ventricle, which may be 
 compared with that of the walls of 
 the right ventricle, r. Entrance of 
 inferior cava into right auricle. 
 
 The inner surface of the sinus is, for the most part, smooth. 
 The septum auricularum, Fig. 133, a, presents no depression, 
 or only a very slight one, corresponding to the fossa ovalis. 
 When an opening does exist between the auricles, a small 
 valvular fold may be observed. The mouths of the pulmo- 
 nary veins, Fig. 133, c, c, c, will be seen, two on the right, 
 and two on the left side. Sometimes the veins on the same 
 
308 DISSECTION OF THE THORAX. 
 
 side open into the auricle by a single orifice. The mouths of 
 the pulmonary veins have no valves. The auriculo-ventricu- 
 lar orifice is situated at the lower and anterior part of the 
 auricle. 
 
 To expose the cavity of the LEFT VENTRICLE, make two in- 
 cisions from the apex to the base, along the septum ventricu- 
 lorum. In doing this, care should be taken not to injure the 
 parts within the cavity. To obtain a good view of the 
 mitral valves, the flap thus raised may be divided into two 
 by making an incision through its centre. 
 
 The general appearance of the interior of the left ventricle 
 is similar to that of the right, and it contains nearly the same 
 number of things to be examined. 
 
 The columnce carnece are not so numerous as in the right, 
 but present the same general arrangement. They are divided 
 into three sets, which are distinguished from each other in 
 the same manner as in the right. Near the mouth of the 
 aorta they are absent, and, consequently, the surface is here 
 smooth. Those which have the chordae tendineae attached to 
 them are larger and stronger than the corresponding ones in 
 the right ventricle. 
 
 The chordae, tendinece are larger, but fewer in number. 
 They connect the mitral valve to the fleshy columns, and at 
 the same time enter into the structure of this valve, and con- 
 tribute much to its strength. 
 
 The mitral valve is situated at the auriculo- ventricular 
 opening. Its structure is similar to that of the tri cuspid 
 valve. Its free margin is usually divided into only two seg- 
 ments. The term mitral has been applied to this valve from 
 its fancied resemblance to a bishop's mitre. The right ante- 
 rior segment is the largest. From its position at the base of 
 the ventricle, it is capable of closing the opening into the 
 aorta, or of assisting in closing the opening into the auricle. 
 The left posterior segment is smaller, and, also, has less 
 mobility. 
 
 The auriculo-ventricular orifice is smaller than the right. 
 Its transverse diameter is greater than its antero-posterior. 
 It is surrounded by a fibrous zone, Avhich is blended in front 
 and to the right side with the fibrous zone which surrounds 
 the aortic opening. When it is viewed from the ventricle, it 
 appears more like a fissure than an oval opening ; this results 
 
THE HEART. 
 
 309 
 
 from the mitral valve having only two segments. The fibrous 
 band which surrounds this opening furnishes an attachment 
 for the muscular walls of the auricle and ventricle, and for 
 the mitral valve. 
 
 The aortic opening is round, and a little smaller than the 
 mouth of the pulmonary artery. It is situated at the right 
 anterior part of the base of the ventricle. There is here 
 no infundibular prolongation upwards to join the aorta, as 
 there is in the right ventricle to join the pulmonary artery, 
 hence the mouth of the aorta is nearly on a level with the 
 opening into the auricle. It is surrounded by a fibrous ring, 
 which forms a medium of attachment for the middle coat of 
 the aorta, the semilunar valves, and the muscular parietes of 
 the ventricle. This ring, it will be observed, is on one side, 
 common to the aortic and auricular orifices, and forms the 
 only septum between them. 
 
 Fig. 184. 
 
 PART OP THE LEFT VENTRICLE, 
 AND COMMENCEMENT OP THE AORTA 
 LAID OPEN TO SHOW THE SlGMOID 
 VALVES. a. Portion of the aorta. 
 v. Muscular wall of the left ventricle. 
 1, 2, 3. Semilunar or sigmoid valves, 
 c, Corpus Arantii in one of them. 
 e. Thin lunated marginal portion 
 or lunula. a, t, t. Sinuses of Val- 
 salva. t, t. Mouths of the two coro- 
 nary arteries of the heart, m. 
 Anterior segment of the mitral 
 valve, the fibrous structure of which 
 is continuous above with the aortic 
 tendinous zone, opposite the attach- 
 ed margin of the sigmoid valve, 
 marked 1. Opposite the valves 2 
 and 3, the tendinous zone receives 
 below the muscular substance of the 
 ventricle v. h. Larger chordae ten- 
 dinse. o, o. Musculi papillares. 
 
 The semilunar or sigmoid valves, and the sinuses of Valsalva, 
 Fig. 134, have the same arrangement at the mouth of the 
 aorta, as at the mouth of the pulmonary artery. The valves 
 are thicker and stronger, while the sinuses are somewhat 
 larger and more distinct. The corpora Arantii in these valves 
 are particularly well marked. In the sinuses, behind the 
 left and anterior valves, will be found the orifices of the 
 coronary arteries. 
 
310 DISSECTION OF THE THORAX. 
 
 The cavities of the heart are lined by a serous membrane 
 which is continuous with the lining membrane of all the 
 vessels which communicate with these cavities. The different 
 valves of the heart are formed, as has been seen, principally, 
 by duplicatures of this membrane. It is not of equal thick- 
 ness throughout its whole extent. It is called the endo- 
 cardium. 
 
 By contrasting the form of the ventricles, and the thick- 
 ness of their walls, they will be found to be quite different. 
 The right ventricle has a pyramidal form, with three well- 
 marked sides ; the inferior is flat, the anterior concave, and 
 the left posterior, which corresponds to the septum ventricu- 
 lorum, is convex. The left ventricle has a conical shape, and 
 consequently presents no particular surface. The base of 
 each ventricle slopes from before backwards, and from above 
 downwards, making the anterior surface longer than the 
 posterior. It should be observed that the left ventricle is 
 partly received into the right. There is probably little or 
 no difference in the size of the two ventricles, although the 
 capacity of the left seems to be much less than that of the 
 right in the dead subject. This is owing to the flaccid con- 
 dition of the walls of the right, while those of the left are 
 firm and contracted. Each ventricle will contain about three 
 ounces of blood. 
 
 The walls of the left ventricle are about three times as 
 thick as those of the right. The thickness, however, varies 
 in each at different points. In the right the thickness is the 
 greatest at the base, while in the left it is greater in the 
 middle than at the base or apex. The thickness of the sep- 
 tum ventriculorum is about the same as that of the walls of 
 the left ventricle, of which it seems rather to be a part, than 
 of the right. The relative thickness of the walls of the 
 ventricles corresponds to the force which each is required to 
 exert in propelling the blood through the vessels. 
 
 The relative position of the four great orifices at the base 
 of the heart should be noticed. To do this the auricles 
 should be detached just above the auriculo- ventricular open- 
 ings, and the pulmonary artery and aorta just above their 
 mouths. The openings between the auricles and ventricles, 
 Fig. 135 (4, 7), will be found to occupy the posterior part and 
 
THE HEART. 
 
 311 
 
 sides of the base of the ventricles, while the mouth of the 
 aorta, Fig. 135 (i o), is situated between and in front of them; 
 the orifice of the pulmonary artery, Fig. 135 (i i), is situated 
 
 Fig. 135. 
 
 A VERTICAL VIEW OF THE AtTRICULO- 
 VENTRICULAR AND ARTERIAL VALVES, 
 AS GIVEN BY A SECTION OF THE HEART 
 AT THE OSTIUM VENOSUM AND OF THE 
 ARTERIES AT THEIR VALVES. 1. De- 
 pression in the left auricle at the left 
 ostium venosuin. 2. Depression in the 
 right auricle at the right ostium veno- 
 suin. 3, 3. Section of the parietes of the 
 left auricle. 4. Superior or auricular face 
 of the two folds of the mitral valve. 5. 
 Section of the greater coronary vein. 
 6, 6. Section of the parietes at the base 
 of the right auricle. 7. Auricular face 
 of the three folds of the tricuspid valve. 
 8. The orifice of the greater coronary 
 vein. 9. Septum of the auricles. 10. 
 A section of the aorta to show its sig- 
 moid valves. 11. The pulmonary artery 
 with its valves. 
 
 in front, and a little above and to the left of that of the 
 aorta. 
 
 These orifices are surrounded by fibrous zones which, taken 
 together, may be regarded as forming the framework of the 
 heart. While they give to each orifice its particular shape, 
 they furnish a fixed attachment for a portion of the muscular 
 parietes of the heart, for the valves, and for the fibrous coats 
 of the aorta and pulmonary artery. The space between the 
 fibrous rings of the auriculo-ventricular openings and the 
 mouth of the aorta, is filled with a dense fibrous substance, 
 which adds greatly to the solidity of this part of the heart. 
 A bone is frequently found in this space, in the hearts of 
 some of the lower animals. 
 
 The heart may be regarded as a hollow muscle, divided 
 into two compartments. These are subdivided into the 
 auricular and ventricular, which have no muscular fibref in 
 common. The muscular parietes of the auricles contain 
 fibres which are common to both, and others which belong 
 to each exclusively. The same is true of the ventricles. The 
 muscular structure of the heart seems to differ from that of 
 every other organ in the body. It partakes, more or less, of 
 
312 ^ DISSECTION OF THE THORAX. 
 
 the character of both the striated and non-striated muscles, 
 and yet is different from either of them. It is exceedingly 
 dense and compact, with scarcely any areolar tissue inter- 
 vening between its fibres or fasciculi. The fibres are vari- 
 ously arranged. Some of them have a parallel direction, 
 while others interlace and intermix with each other. In 
 function, the heart is closely allied to the non-striated or in- 
 voluntary muscles. 
 
 The MUSCULAR FIBRES OF THE AURICLES, Fig. 136, are 
 divided into the proper and common. The common have a 
 transverse direction, and are, for the most part, superficial. 
 They are attached to and extend between the fibrous zones 
 of the auriculo-ventricular orifices. They form a very distinct 
 layer on the anterior walls behind the aorta. Some fibres 
 pass into the septum auriculorum. The proper fibres have 
 not the same arrangement in the two auricles. In the left, 
 they are expanded over the parietes so as to form a smooth 
 even surface. They consist of fasciculi, which have either a 
 circular or oblique direction, and are attached to the fibrous 
 ring of the opening into the ventricle. Fasciculi spread 
 out between the orifices of the right and left pulmonary 
 veins, and also pass between and around those of the same 
 side. Some fibres surround the auriculo-ventricular open- 
 ing ; others pass into the septum auriculorum, while others 
 still mix with the common or superficial fibres. In the 
 auricula, they form a network. In the right auricle, the 
 fibres are arranged more distinctly in fasciculi, leaving between 
 them interspaces in which the endocardium and pericardium 
 are separated merely by areolar tissue ; they are also limited 
 to a portion of the walls. The direction of the fibres varies, 
 being either oblique or circular. They are attached to the 
 fibrous zone of the auriculo-ventricular opening. In the 
 auricula, they form a reticulated arrangement. 
 
 The MUSCULAR FIBRES OF THE VENTRICLES, Fig. 136, like 
 those of the auricles, are divided into the common and proper. 
 The common fibres consist of two portions, the superficial, 
 and the deep-seated or the reflected. The superficial fibres 
 are situated on the outside of the proper, and become the deep- 
 seated, or reflected fibres, after they have penetrated the cavities 
 of the ventricles at their apices. If they be traced, they will 
 
THE HEART. 
 
 313 
 
 Fig. 136. 
 
 be found to arise from the auriculo- 
 ventricular zones, and to pass down- 
 wards, those in front from right to 
 left, and those behind from left to 
 right, to the apex of the heart. As 
 they enter the ventricles, those from 
 behind twist round those from be- 
 fore, so as to form a stellated ap- 
 pearance. Having entered the 
 cavities of the ventricles, they pass 
 upwards on the side opposite to 
 the one upon which they descended; 
 so that the fibres which assist in 
 forming the anterior walls as they 
 descend on the outside, will assist 
 in forming the posterior walls as 
 they ascend on the inside. Some 
 of them terminate by being inserted 
 into the fibrous zones, and others 
 in the columnae carneas. As many 
 of the superficial fibres penetrate 
 the ventricles before reaching the 
 apex, loops of different lengths are 
 formed one within another, thus 
 increasing the thickness of the 
 ventricular parietes from the apex 
 towards the base. 
 
 The proper fibres of the ventri- 
 cles form two hollow truncated 
 
 cones, which are covered on the outside by the superficial 
 portion of the common fibres, and on the inside by the re- 
 flected portion. There is one cone for each ventricle. Their 
 bases are connected to the fibrous zones around the auriculo- 
 ventricular openings. They are composed of circular, oblique, 
 and spiral fibres. 
 
 To unravel the muscular structure of the. heart, the stu- 
 dent should begin with that of a bullock. This should be 
 prepared by boiling and maceration, until the fibres can be 
 loosened up, and separated from each other. It will require 
 much time and patience to trace out the different fibres and 
 their connections. 
 27 
 
 A POSTERIOR VIEW OP THE EX- 
 TERNAL MUSCULAR LAYER OF 
 THE HEART AFTER THE REMOVAL 
 OF ITS SEROUS COAT, Ac. 1. 
 Right auricle. 2. Descending 
 vena cava. 3. Right posterior 
 pulmonary vein. 4. Muscular 
 fibres of the left auricle. 5. Left 
 posterior pulmonary vein. 6, 7. 
 The arrangement of the muscular 
 fibres at the end of the left auri- 
 cle. 8. Orifice of the great coro- 
 nary vein. 9. Band of fibres be- 
 tween the two venge cavas. 10. 
 The orifice of the ascending vena 
 cava; the Eustachian valve is at 
 the end of the line. 11, 12. Mus- 
 cular fibres at the base of the 
 auricle. 13, 13, 14. Muscular 
 fibres in the ventricles. 
 
314 DISSECTION OF THE THORAX. 
 
 The vessels of the heart consist of a right and left coronary 
 artery, and a coronary vein. 
 
 The EIGHT CORONARY ARTERY, Fig. 130 (i i), arises from 
 the aorta above the anterior semilunar valve. At first, it is 
 concealed by the conus arteriosus, between which and the 
 right auricle, it passes to enter the auriculo-ventricular groove ; 
 it winds round in this groove to the posterior part of the heart, 
 where it divides into two branches, one to go along the pos- 
 terior vertical groove to the apex of the heart, and the other 
 to continue in the auriculo-ventricular groove, until it anas- 
 tomoses with the left coronary artery. It gives off quite a 
 large branch, which ramifies over the anterior and right por- 
 tion of the right ventricle. 
 
 The LEFT CORONARY ARTERY, Fig. 131 (10, n), arises 
 near the root of the aorta, above the left semilunar valve. It 
 passes between the conus arteriosus and the left auricle, 
 soon divides into two branches, the largest of which enters 
 the anterior vertical groove, and goes to the apex of the 
 heart ; the other and smaller branch enters the auriculo-ven- 
 tricular groove, and terminates by anastomosing with the 
 corresponding branch of the right coronary. The coronary 
 arteries anastomose freely with each other, not only at the 
 apex and in the horizontal sulcus, but in different parts of 
 the parietes of the heart. They vary in number and in the 
 manner of their distribution. 
 
 The CORONARY VEIN, Fig. 131 (9), commences at the apex 
 of the heart, and ascends along the anterior vertical groove 
 to the sulcus between the left auricle and ventricle, in which 
 it continues to the posterior part of the heart, where it opens 
 into the right auricle. In its ascending course, it receives 
 branches from the anterior parietes of the ventricles ; as it 
 winds round to the back of the heart, it increases very much 
 in size, as it receives branches from the posterior parietes of 
 the ventricles, and from the left auricle ; one of these branches 
 occupies the posterior vertical groove, and is called the mid- 
 dle coronary or cardiac vein. Besides the coronary vein and 
 its branches, there are several small anterior cardiac veins, 
 which open into the lower part of the right auricle. The 
 coronary veins have no valves. 
 
 The nerves which supply the heart consist of two plexuses, 
 the anterior and posterior coronary. These are derived from 
 
THE MEDIASTINUM. 315 
 
 the superficial and deep cardiac plexuses, which will be de- 
 scribed in connection with the contents of the superior medi- 
 astinum. They accompany the coronary arteries only for a 
 short distance, when they leave them to divide into branches 
 to be distributed to the parietes of the heart. They can be 
 seen for some distance in their course towards the apex of the 
 heart, beneath the serous membrane ; they are more distinct 
 in a heart which has been macerated for a few days in alcohol. 
 
 The student should now proceed to examine the contents of 
 the POSTERIOR MEDIASTINUM. They are readily exposed by 
 dissecting the pericardium from the diaphragm, and detaching 
 the pleura on each side as it is reflected from the pericardium 
 to the vertebras and ribs. They consist of the oesophagus, 
 the aorta, the azygos vein, the thoracic duct, and the pneumo- 
 gastric nerves. The great splanchnic nerves enter this space 
 just before they pass through the diaphragm. These parts 
 should be preserved, to be referred to again in the examina- 
 tion of the contents of the superior mediastinum, in which 
 they are also found. 
 
 The oesophagus occupies the anterior part of this space, 
 immediately behind the pericardium. It has the left pneumo- 
 gastric nerve adhering to it in front, and the right behind. It 
 perforates the diaphragm opposite the ninth dorsal vertebra. 
 
 The aorta, in passing through this region, has a direction 
 somewhat oblique from the left to the right. It is situated 
 on the left side, and is partly covered by the left pleura. The 
 branches which it gives off, in this part of its course, will be 
 noticed at another time. It enters the abdomen between 
 the crura of the diaphragm, where it rests on the eleventh 
 and twelfth dorsal vertebras. The vena azygos is placed on the 
 right side ; it is partly covered by the right pleura. It enters 
 this space from the abdomen through the aortic opening in 
 the diaphragm. The thoracic duct lies between the azygos 
 vein and the aorta, and behind the oesophagus. It requires 
 some care to be able to distinguish it from the areolar tissue 
 around it. It passes through the diaphragm with the aort^ 
 and vena azygos. The splanchnic nerves will be seen on the 
 sides of the bodies of the vertebras gradually getting more 
 in front of them to perforate the crura of the diaphragm. 
 
 The contents of the SUPERIOR MEDIASTINUM are numerous, 
 and their arrangement somewhat complex. The student, in 
 his examination of them, should pursue a systematic course, 
 
316 DISSECTION OF THE THORAX. 
 
 so that he may learn the position and relations of each part. 
 His greatest difficulty will be to dissect out some parts, and 
 preserve them, so as to see and learn their relations without 
 destroying other parts. This difficulty may, however, to a 
 considerable extent, be overcome, if he will carefully read a 
 description of what he is to look for before he commences 
 his dissection. 
 
 The following are the things to be found and examined in 
 this dissection : The remains of the thymus gland, the vena 
 innominata, the vena transversa, the vena cava descendens, 
 the vena azygos, and several smaller veins, as the superior 
 intercostal, the thyroid, the mediastinal, and the bronchial ; 
 the aorta, the arteria innominata, the left common carotid, 
 the left subclavian, the bronchial, and the cesophageal arteries; 
 the pulmonary arteries and veins; the pneumogastric, the 
 phrenic, and the sympathetic nerves; the trachea; the oeso- 
 phagus ; the thoracic duct ; and the bronchial glands. 
 
 The THYMUS GLAND in the adult subject, exists only in the 
 form of a small quantity of cellulo-adipose substance. In 
 the old subject, very frequently, no trace of it is to be found. 
 In the latter part of foetal life, and for some time after birth, 
 it exists as quite a large body, reaching from a short distance 
 below the thyroid gland nearly down to the diaphragm. It 
 may become so large, especially in scrofulous children, as to 
 cause death by pressing upon the trachea, or the oesophagus 
 and other parts which are situated beneath it. 
 
 The phrenic nerves should be sought and traced in the early 
 stage of the dissection ; this can be done without disturbing 
 other parts. The right nerve enters the thorax between the 
 subclavian vein and artery. As it descends it has on the outer 
 side the vena innominata covered by the pleura, and on the 
 inner side the vena cava descendens and the pericardium. It 
 passes in front of the root of the lung. The left nerve de- 
 scends at first between the pleura and the left carotid artery ; 
 it then passes in front of the left portion of the arch of the 
 aorta and the root of the lung to get between the pleura and 
 the pericardium. These nerves are accompanied by small 
 branches of the internal mammary arteries. 
 
 The following veins may next be examined : 
 
 The VENA INNOMINATA, Fig. 139 (n), is formed by the 
 junction of the right subclavian and internal jugular, be- 
 hind the sternal end of the right clavicle ; it passes down- 
 
CONTENTS OF MEDIASTINUM. 317 
 
 wards about an inch and a half, where it unites with the vena 
 transversa to form the descending cava. 
 
 The VENA TKANSVEKSA, Fig. 139 (14), commences behind 
 the sternal extremity of the left clavicle, where it is formed 
 by the union of the left subclavian and internal jugular veins; 
 from this point it descends obliquely to the right, about three 
 inches, to join the descending cava. It is usually somewhat 
 larger than the innominata. It lies above the arch of the 
 aorta, and rests on the great arteries which arise from it. 
 It is separated from the sternum by the remains of the thy- 
 mus gland and by areolar tissue. 
 
 There are several small veins which open into the venae 
 innominata and transversa. The former receives the right 
 vertebral, and generally the right internal mammary and inferior 
 thyroid; the latter has opening into it the corresponding veins 
 on the left side, and also the thymic, the pericardiac, the supe- 
 rior phrenic, and the superior intercostal. These veins vary 
 very much in their termination in different subjects. 
 
 The YENA CAVA DESCENDENS, Fig. 139 (to), commences 
 opposite the first intercostal space, descends to near the car- 
 tilage of the third rib, where it perforates the fibrous lamina 
 of the pericardium, and thence continues down to the right 
 auricle. It has the pleura and phrenic nerve on the right 
 side, the aorta on the left, and the trachea, the right pulmo- 
 nary artery, and superior pulmonary vein behind. Just be- 
 fore it enters the pericardium it receives the vena azygos, 
 which passes up behind the root of the lung, and then bends 
 forwards to terminate in the cava. 
 
 The bronchial veins terminate, the right in the vena azygos, 
 and the left in the superior intercostal. To obtain a good 
 view of the vena azygos, the heart and lungs should be re- 
 moved from the thorax. 
 
 The PNEUMOGASTRIC NERVES should now be examined. 
 The right nerve enters the thorax between the subclavian vein 
 and artery, crossing the latter nearly at a right angle ; it then 
 descends behind the vena innominata and on the side of the tra- 
 chea to reach the groove between the latter and the oesophagus, 
 in which it continues until it gets behind the root of the right 
 lung. The left nerve enters the thorax behind the vena trans- 
 versa, and between the subclavian and common carotid arte- 
 
 27* 
 
318 DISSECTION OF THE THORAX. 
 
 ries ; it then descends between these arteries to the aorta, 
 which it crosses over and then dips down behind the root of 
 the left lung. Each nerve gives off a recurrent laryngeal 
 branch ; the right just as it passes over the subclavian artery, 
 and the left as it crosses the aorta. The left recurrent 
 branch winds round behind the aorta, and ascends to the 
 larynx in the groove between the trachea and the oeso- 
 phagus; the right passes round the subclavian artery and 
 ascends to the larynx in the corresponding groove on the 
 right side. The recurrent nerves give off cardiac, cesopha- 
 geal, tracheal, and pharyngeal branches. The left is longer 
 than the right, and gives off more cardiac branches. 
 
 Each pneumogastric nerve forms two pulmonary plexuses, 
 one in front and one behind the root of the lung. The one 
 in front, called the anterior pulmonary plexus, is formed by 
 filaments which leave the nerve just above the root of the 
 lung ; it also receives filaments from the phrenic and cardiac 
 nerves. The one behind, named the posterior pulmonary 
 plexus, consists of a plexiform arrangement of the filaments 
 of the nerve itself; it receives filaments from the anterior 
 plexus, and from the cardiac nerves. The pulmonary plex- 
 uses give off filaments which accompany the bronchial tubes, 
 and ramify minutely in the lungs. The pneumogastric nerves, 
 after forming the posterior pulmonary plexuses, join the oeso- 
 phagus, which they accompany to the stomach. Filaments 
 from each unite round this tube to form the plexus gulce. 
 
 It is somewhat difficult to dissect out the posterior pulmo- 
 nary plexuses, as their filaments are intermixed with glands 
 and areolar substance. There is an interchange of filaments 
 between the two plexuses which establishes a direct sympa- 
 thetic connection between the two lungs. The left plexus is 
 considerably larger than the right. 
 
 The AORTA commences at the anterior and inner part of 
 the base of the left ventricle, opposite to the junction of the 
 cartilage of the fourth rib and sternum, on the left side. From 
 this point it proceeds upwards, forwards, and to the right 
 side as far as the junction of the cartilage of the second rib 
 with the sternum ; it then turns to the left and goes back- 
 wards to the body of the second dorsal vertebra, where it 
 curves downwards and somewhat inwards on the side of the 
 vertebras, to enter the posterior mediastinum. 
 
 This part of the aorta is divided into the ascending, trans- 
 
CONTENTS OF MEDIASTINUM. 
 
 319 
 
 verse, and descending portions, which together form what is 
 denominated the arch of the aorta. At its commencement, 
 the ascending portion, Fig. 137 (i), lies behind the infundibu- 
 lar process of the right ventricle and the pulmonary artery, 
 
 Fig. 137. 
 
 THE LARGE VESSELS AVHICH 
 PROCEED FROM THE ROOT OF 
 THE HEART, WITH THEIR RE- 
 LATIONS; THE HEART HAS 
 
 BEEN REMOVED. 1. The as- 
 
 cending aorta. 2. The arch. 
 3. The thoracic portion of 
 the descending aorta. 4. The 
 arteria innominata, dividing 
 into, 5, the right carotid, 
 which again divides at 6, 
 into the external and inter- 
 nal carotid ; and 7, the right 
 subclavian artery. 8. The 
 axillary artery ; its extent is 
 designated by a dotted line. 
 9. The brachial artery. 10. 
 The right pneumogastric 
 nerve running by the side of 
 the common carotid, in front 
 of the right subclavian artery, 
 and behind the root of the 
 right lung. 11. The^ft 
 common carotid, having to its 
 outer side the left pneumo- 
 gastric nerve, which crosses 
 the arch of the aorta, and as 
 it reaches its lower border is 
 seen to give off the left re- 
 current nerve. 12. The left 
 subclavian artery becoming 
 axillary and brachial in its 
 course, like the artery of the 
 opposite side. 13. The trunk 
 of the pulmonary artery connected to the concavity of the arch of the aorta by a 
 fibrous cord, the remains of the ductus arteriosus. 14. The left pulmonary artery. 
 15. The right pulmonary artery. 16. Tlie trachea. 17. The right bronchus. 18. 
 The left bronchus. 19, 19. The pulmonary veins. 17, 15, and 19, on the right 
 side, and 14, 18, and 19, on the left, constitute the roots of the corresponding lungs, 
 and the relative position of these vessels is preserved. 20. Bronchial arteries. 21, 
 21. Intercostal arteries; the branches from the front of the aorta above and below 
 the number 3 are pericardiac and oesophageal branches. 
 
 but as it ascends it gradually approaches the sternum, from 
 which the upper part is separated only by the pericardium, 
 the remains of the thy m us gland, and areolar tissue. It has 
 the right auricle and the descending cava on the right side 
 of it ; the pulmonary artery, at first in front and then on the 
 left side ; and behind, the right pulmonary artery and veins. 
 
320 DISSECTION OF THE THORAX. 
 
 The principal part of it is contained in the pericardium, and 
 invested by the serous lamina of that membrane. The trans- 
 verse portion, sometimes called the arch, Fig. 137 (2), lies 
 nearest to the sternum. The vena transversa lies imme- 
 diately above it, resting on the arteria innominata and the 
 left common carotid and subclavian arteries. The ductus 
 arteriosus and the right pulmonary artery occupy its cardiac 
 aspect, while the trachea is in contact with it behind. The 
 descending portion, Fig. 137 (3), has in front of it the left 
 phrenic and pneumogastric nerves, and the root of the left 
 lung. On the left side, and behind, it is in relation with the 
 pleura and the body of the third dorsal vertebra. 
 
 The attention of the student should be directed especially 
 to this great vessel, as it furnishes a key to the study of the 
 relations of almost all the other parts found in the superior 
 mediastinum. Besides, a knowledge of it is of the utmost 
 importance, if we wish to understand the nature and the 
 results of aneurisms, which are formed in it. 
 
 The ARTERIA INNOMINATA, Fig. 137 (4), arises from the 
 arch of the aorta, near the median line, and extends obliquely 
 upwards to a point behind the right sterno-clavicular articula- 
 tion. It varies in length from an inch to an inch and a half. 
 It is separated from the sternum by the vena transversa, the 
 sternal muscles and areolar tissue ; on the right side, it is in 
 relation with the vena innominata and the pleura ; behind, 
 it rests, at first, on the trachea, and then gets to its right side ; 
 on the left side, it is separated from the left common carotid 
 artery by a triangular space, in which the trachea is seen. 
 This artery divides into the right common carotid and subcla- 
 vian. It sometimes gives off one or two small branches, 
 especially the middle thyroid, or the artery of Keubauer. 
 
 The LEFT COMMON CAROTID ARTERY, Fig. 137 (i i), arises 
 from the arch of the aorta immediately to the left of the inno- 
 minata. It passes obliquely upwards to the left, to reach the 
 neck. The vena transversa and the sternal muscles lie in 
 front of it ; the trachea and oesophagus are behind it ; the 
 pleura partly covers it on the left side. 
 
 The LEFT SUBCLAVIAN ARTERY, Fig. 137 (i 2), arises from 
 the aorta to the left and behind the left common carotid. Its 
 direction is nearly vertical. It is covered on the left side by 
 
THE TRACHEA. 821 
 
 the pleura ; the pneumogastric and phrenic nerves, the vena 
 innominata, and the sternal muscles are in front of it ; the 
 trachea and oesophagus are on the inside of it. 
 
 The arteries just described vary a good deal in their origin 
 from the arch of the aorta. 
 
 The PULMONARY ARTERY, Fig. 137 (i s), is from an inch and 
 a half to two inches in length. It passes upwards, backwards, 
 and somewhat to the left. At first, it is in front of the aorta, 
 and then gets to its left side. Nearly the whole of it is covered 
 by the serous layer of the pericardium. It divides into the 
 right and left pulmonary arteries. At its bifurcation, the 
 remains of the ductus arteriosus is found extending from it 
 to a point on the arch of the aorta, nearly opposite to the 
 origin of the left subclavian artery. 
 
 The EIGHT PULMONARY ARTERY, Fig. 137 (i 5), is directed 
 transversely to the root of the right lung. It is about an 
 inch and a half in length. It passes behind the aorta and 
 the vena cava descendens, and in front and a little below the 
 right bronchus. In the root of the lung, it divides into three 
 branches. The serous lamina of the pericardium is reflected 
 upon a portion of this artery. 
 
 The LEFT PULMONARY ARTERY, Fig. 137 (M), is quite 
 short. It proceeds to the left lung in front, and a little above 
 the left bronchus, and also in front of the descending portion 
 of the aorta. It divides into two primitive branches. 
 
 The PULMONARY VEINS, Fig. 137 (i 9,1 9), consist of four 
 principal trunks, two for each lung. These are formed by 
 branches, which originate in the walls of the air-cells of the 
 lungs. One of the right veins is formed by branches proceed- 
 ing from the lower lobe, while the other is formed by branches 
 from the middle and superior lobes. The former has a trans- 
 verse, and the latter an oblique direction towards the left 
 auricle. In the root of the lung on each side, the veins are 
 situated anteriorly, the bronchus posteriorly, and the artery 
 in the middle. From above downwards, on the right side, 
 the bronchus is situated above, the veins below, and the artery 
 in the middle ; while, on the left side, the artery is placed 
 above, and the bronchus in the middle. 
 
 The TRACHEA, Fig. 138 (7), extends from the fifth cervical 
 vertebra above to the third dorsal below ; it commences at 
 
322 DISSECTION OF THE THOEAX. 
 
 the inferior border of the cricoid cartilage, and terminates by 
 its bifurcation into the two bronchi. It is about five inches 
 in length, and is nearly equally divided in its cervical and 
 thoracic portions. Its diameter is about ten lines in the male, 
 and a little less in the female. Sometimes it increases in 
 diameter from above downwards. Its direction is downwards, 
 backwards, and a little to the right side. In the thorax, it has 
 the oesophagus behind, and one of the pneumogastric nerves 
 on each side of it ; the left recurrent nerve and left common 
 carotid artery are on the left and the upper part of the arteria 
 innominata on the right side; the lower part of the last 
 named artery and the arch of the aorta are in front of it. 
 
 The bronchi, Fig. 138 (s, 9), extend from the trachea into 
 the roots of the lungs. The right forms nearly a right angle 
 with the trachea ; it is about an inch and a quarter in length, 
 and half an inch in diameter. The vena azygos winds around 
 it to enter the descending cava. The left bronchus is longer, 
 and has a more oblique direction downwards than the right, 
 to reach the root of the left lung ; it also has a smaller caliber. 
 The oesophagus and descending aorta pass behind it. The 
 bronchi at the bifurcation of the trachea are connected to- 
 gether by quite a strong ligament. The triangular space 
 between them is filled with bronchial glands, which usually 
 have a very dark appearance. Filaments from the anterior 
 and posterior pulmonary plexuses accompany the bronchial 
 tubes into the substance of the lungs. 
 
 The trachea, together with the bronchi and lungs, may be 
 removed from the thorax, for the purpose of examining their 
 structure. But, before doing this, the bronchial arteries, Fig. 
 137 (2 o), should be noticed. They arise from the descending 
 aorta, and vary in number ; there may be two, three, or four. 
 Sometimes one arises from the internal mammary, or the 
 superior intercostal. They join the bronchi, and accompany 
 them in their subdivisions through the lungs, which they 
 supply with arterial blood, for their nourishment. The 
 bronchial veins convey the blood which is transmitted to the 
 lungs by the bronchial arteries into the vena azygos and the 
 superior intercostal vein. 
 
 The trachea is composed of imperfect cartilaginous rings, 
 of muscular and fibrous tissue, and of glands and mucous 
 membrane. There are from sixteen to eighteen cartilaginous 
 
THE TEACHEA. 
 
 323 
 
 rings ; they form the framework of the tube, keeping it con- 
 stantly open for the transmission of air to and from the lungs. 
 Each ring embraces about three-fourths of the circumference 
 
 Fig. 138. 
 
 THE LARYNX, TRACHEA AND BRONCHI, DEPRIVED OF THEIR FIBROUS COVERING; 
 also THE OUTLINE OP THE LUNGS. 1, 1. Outline of the upper lobes of the 
 lungs. 2. Outline of the middle lobe of the right lung. 3, 3. Outline of the infe- 
 rior lobes of both lungs. 4. Outline of the 9th dorsal vertebra, showing its relation 
 to the lungs and the vertebral column. 5. Thyroid cartilage. 6. Cricoid cartilage. 
 7. Trachea. 8. Right bronchus. 9. Left bronchus. 10. Crico-thyroid ligament. 
 11, 12. Rings of the trachea. 13. First ring of the trachea. 14. Last ring of the 
 trachea, which is corset-shaped. 15, 16. A complete bronchial cartilaginous ring. 
 17. One which is bifurcated. 18. Double bifurcated bronchial rings. 19,19. Smaller 
 bronchial rings. 20. Depressions for the course of the large bloodvessels. 
 
 of the trachea, leaving one-fourth behind to be filled by mus- 
 cular fibres. They are more distinct on the inner than on the 
 outer surface. The first ring is usually broader than the 
 others, while the last two are larger. Frequently, two or 
 three of them coalesce in some part of their circumference. 
 
324 DISSECTION OF THE THORAX. 
 
 They are strong, elastic, and not easily broken. The last one 
 consists of two segments of smaller circles, united at their 
 inner extremities. Each of these segments is the commence- 
 ment of one of the bronchi. 
 
 The fibrous tissue is the yellow elastic kind. It forms a com- 
 plete tube, which is attached to the cricoid cartilage above, 
 and is lost below in the bronchi. The cartilaginous rings are 
 imbedded in it, and are more thickly covered by it on their 
 external than on their internal surface ; hence the difference 
 in the prominence of the rings on the two surfaces. On the 
 inside of the muscular portion of the tube, the elastic tissue 
 forms, apparently, longitudinal folds, which, however, result 
 from the fibres of this tissue being arranged in fasciculi. The 
 use of the elastic tissue in the trachea is very evident. It con- 
 tributes greatly to its strength, and, by its elasticity, prevents 
 displacement of the organs with which the trachea is connected 
 above and below, when the head is thrown backwards. The 
 trachea may be stretched to the extent of an inch or more, 
 and recover its natural length as soon as the force is removed. 
 
 The muscular fibres are situated behind, being attached to 
 the ends of the cartilaginous rings. They have a transverse 
 direction, and belong to the non-striated or involuntary class 
 of muscles. They approximate the ends of the cartilages, 
 and thus diminish the size of the tube. They also form a 
 flattening of the trachea behind where it rests upon the 
 oesophagus, which may facilitate the passage of the food 
 to the stomach. 
 
 The mucous membrane of the trachea is continuous with that 
 of the larynx above, and that of the bronchi below. It is 
 thin and transparent, and adheres closely to the subjacent 
 tissues. It is perforated by numerous small foramina, through 
 which the secretion from the tracheal glands is poured out 
 upon the inner surface of the trachea. 
 
 The tracheal glands consist of numerous small glandular 
 bodies, situated in the parietes of the trachea. Those found 
 behind, in the membranous part, are the largest. They are 
 placed outside of the muscular layer, between it and the 
 fibrous layer. The others are contained in the fibrous tissue 
 between the rings. 
 
 The bronchi may be regarded as a continuation of the tra- 
 chea in two divisions. They have the same elements, with 
 the same arrangement in their structure. The left bronchus 
 
THE LUNGS. 325 
 
 has eight or ten, and the right five or six cartilaginous 
 rings. 
 
 The LUNGS (Fig. 139) have already been observed in situ in 
 examining the pleurae. To obtain a good view of their form 
 and external appearance, they should be inflated after their 
 removal from the thorax. If they be not injured in their 
 removal, they will retain the air a sufficient length of time 
 to allow of a satisfactory inspection. Each lung presents 
 three surfaces, a costal, a diaphragmatic, and a mediastinal. 
 
 The costal surface is convex, and corresponds to the ribs 
 and intercostal spaces, being in apposition with the pleura 
 costalis. This surface presents two fissures in the right lung, 
 which divides it into three lobes, Fig. 139 (21, 22, 23). The 
 principal one commences behind, just below the apex, 
 and extends downwards and forwards to the base near its 
 inner margin ; the other, and smaller one, extends from this 
 forward and somewhat downwards to the anterior border of 
 the lung. The first one is much deeper than the last ; it 
 reaches entirely to the root of the lung. The left lung has 
 but one fissure, which corresponds to the large one in the 
 right; consequently, this lung has but two lobes, Fig. 139 
 (24, 25). The number of lobes, however, is subject to va- 
 riation in both lungs. 
 
 The diaphragmatic surface is concave, and sloping from 
 before backwards and downwards, so that the vertical dia- 
 meter of the lung is considerably greater behind than before. 
 The concavity of the right is deeper than that of the left, 
 on account of the liver pushing the diaphragm higher up 
 on the right side. The margin of this surface presents quite 
 a sharp edge, which projects in between the diaphragm and 
 the costal parietes of the thorax. 
 
 The mediastinal surface is in contact with the pleura medi- 
 astinalis. This surface in each has a concavity for the re- 
 ception of the heart ; the one in the left is the deepest, on 
 account of the heart projecting more on the left than on the 
 right side. The posterior border is round, and nearly straight 
 from the apex to the base of the lung ; while the anterior is 
 sharp, oblique, and notched; the left for the apex of the 
 heart, and the right for the right auricle ; besides these 
 notches, there is a small one on the right side for the de- 
 scending; cava, and another on the left for the subclavian 
 28 
 
326 DISSECTION OF THE THORAX. 
 
 artery. The apex of each lung is round, and projects some 
 distance above the first rib ; the right more than the left. 
 
 The color of the lung varies at different periods of life. In 
 the child it is a pale red, while in the adult it is of a grayish 
 blue, interspersed with dark spots, which increase in number 
 as age advances. The posterior part after death usually 
 presents, from hypostatic congestion, quite a dark hue. Lines 
 may be observed on the surface of the lung through the 
 pleura, which indicate the septa between the lobules. 
 
 The right lung is somewhat larger than the left. The di- 
 mensions of the two lungs are not precisely the same ; the 
 vertical diameter of the left lung is the greatest, while the 
 base of the right is rather larger than that of the left. The 
 lungs of the male are usually larger than those of the female. 
 In proportion to their bulk the lungs are very light ; this is 
 owing to the air which is never wholly expelled from the cells 
 after it has once entered them. When cut into they have a 
 spongy appearance, and when a portion is compressed be- 
 tween the thumb and fingers the air can be felt escaping 
 from the cells. The resiliency of the lung is well shown in 
 the force with which it expels the air when it has been in- 
 flated. This contractile power exists in the yellow fibrous 
 tissue which enters into its structure. 
 
 The lung contains in its structure all the elements which 
 are found in its root. They consist of the ramifications of the 
 pulmonary artery and veins, the bronchial arteries, veins, and the 
 bronchi, together with nerves and absorbent vessels, and the 
 parenchyma which holds all the other parts in situ. If a 
 bronchus be traced into the substance of the lung, it will be 
 found to divide and subdivide until it ultimately terminates 
 in the air-cells; The mode of division observed is dichoto- 
 mous ; that is, the bronchus divides into two tubes, and each 
 of these again divides into two others, and so on until the 
 last division takes place. 
 
 The structure of the bronchial ramifications, after the first 
 two or three divisions, undergoes some modification. The 
 cartilaginous segments, instead of being arranged on one side 
 of the tube as in the trachea, are distributed on all sides of 
 it, with their extremities overlapping each other. This ar- 
 rangement continues to the last division, the segments, how- 
 ever, becoming more and more imperfect until they dis- 
 
THE LUNGS. 327^ 
 
 appear altogether. The muscular fibres connect the ends of 
 the cartilages together and form on their inner aspect a 
 
 Fig. 139. 
 
 ANATOMY OF THE HEART AND LUNGS. 1. The right ventricle ; the vessels to the 
 left of the number are the middle coronary artery and veins ; and those to its 
 right, the anterior coronary artery and veins. 2. The left ventricle. 3. The 
 right auricle. 4. The left auricle. 5. The pulmonary artery. 6. The right 
 pulmonary artery. 7. The left pulmonary artery. 8. The remains of the ductus 
 arteriosug. 9. The arch of the aorta. 10. The descending vena cava. 11. The 
 arteria innominata, and in front of it the vena innominata. 12. The right sub- 
 clavian vein, and, behind it, its corresponding artery. 13. The right common ca- 
 rotid artery and vein. T4. The vena transversa. 15. The left carotid artery 
 and vein. 16. The left subclavian vein and artery. 17. The trachea. 18. The 
 right bronchus. 19. The left bronchus. 20, 20. The pulmonary veins ; 18, 20, 
 form the root of the right lung; and 7, 19, 20, the root of the left. 21. The supe- 
 rior lobe of the right lung. 22. Its middle lobe. 23. Its inferior lobe. 24. The. 
 superior lobe of the left lung. 25. Its inferior lobe. 
 
 complete muscular tube. The mucous membrane and fibrous 
 tissue are prolonged into the lobular tubes, with which the 
 cells communicate directly. The cells are not lined by mu- 
 cous membrane, but have a thin, delicate, fibrous lamina 
 forming their walls, upon which the capillaries of the pul- 
 monary vessels ramify. 
 
 Each lobule is composed of a cluster of air-cells, which 
 communicate with a tube common to them ; of pulmonary 
 
328 
 
 DISSECTION OF THE THOEAX. 
 
 and bronchial vessels, nerves, and absorbents, so that it may 
 be regarded as representing the entire lung. 
 
 The pulmonary artery accompanies the bronchial ramifica- 
 tions in all their subdivisions, and finally forms a capillary 
 network by anastomosing freely with the radicals of the pul- 
 monary veins in the parietes of the air-cells. The pulmo- 
 nary veins, commencing in the walls of the cells, accompany 
 the bronchial tubes to the root of the lung. The bronchial 
 vessels , nerves, and absorbents are all found ramifying with the 
 air-tubes in the substance of the lung. The nerves are de- 
 rived from the pneumogastric and sympathetic. The ab- 
 sorbent vessels consist of two sets, the deep and the superficial; 
 they terminate in the bronchial glands. 
 
 The OESOPHAGUS has been noticed in the neck, and also in 
 the posterior mediastinum. It is a muscular tube, com- 
 mencing at the lower orifice of the pharynx and extending 
 to the stomach. It is the smallest section, in diameter, of the 
 alimentary canal, being usually less than an inch. It is 
 narrower above than below, except where it passes through 
 the diaphragm. It is composed of three layers ; a mucous, 
 cellular, and muscular. The mucous mem- 
 brane is a continuation of that of the pha- 
 rynx. It is thrown into longitudinal folds 
 when the oesophagus is empty. The cellular 
 layer is intermediate to the other two, and 
 allows of a somewhat loose connection be- 
 tween them. The muscular layer, Fig. 140 
 (i, i, 2, 2), consists of longitudinal and cir- 
 cular fibres ; the latter are internal to the 
 former. The longitudinal fibres arise in 
 part from the posterior aspect of the cricoid 
 cartilage, and terminate in the muscular 
 parietes of the stomach. The circular fibres 
 cease at the cardiac orifice of the stomach. 
 They all belong to the involuntary class of 
 muscles. 
 
 In the superior mediastinum, the cesopha- 
 
 A VIEW OP A PORTION OF THE (ESOPHAGUS OP AN ADULT, SEEN ON ITS OUTER 
 
 SIDE. 1, 1. External or longitudinal muscular fibres. 2, 2. Internal or circular 
 fibres, as shown after the removal of the longitudinal ones. 3, 3. The cut edges 
 of the longitudinal fibres, from which a portion has been removed, so as to show 
 the circular ones. 
 
 Fig. 140. 
 
THE THORACIC DUCT. 329 
 
 gus lies in front of the vertebral column, and behind the tra- 
 chea, being inclined a little to the left side. Its relations to the 
 aorta in passing through the thorax are changed. At first it 
 passes beneath the arch, then to the right of the descending 
 aorta, and finally it gets nearly in front of it. Its course is 
 slightly flexuous. 
 
 The course of the aorta has already been observed. It 
 gives off, besides the branches previously described, the oeso- 
 phageal and intercostal The oesophageal branches, Fig. 137 (3), 
 vary in number and origin. There may be three, four, or 
 more of them. They divide, after reaching the oesophagus, 
 into ascending and descending branches, which perforate the 
 muscular coat and ramify beneath the mucous membrane. 
 
 The intercostal arteries, Fig. 137 (21, 21), arising from the 
 aorta, usually consist of nine or ten on each side ; the supe- 
 rior intercostal spaces being supplied from the subclavian 
 arteries. They arise from the posterior part of the aorta, 
 and proceed laterally to enter the intercostal spaces. Those 
 on the right side, especially the superior ones, are much 
 longer and more oblique in the first part of their course than 
 the corresponding ones on the left side. As the intercostals 
 enter the intercostal spaces, they give off posterior branches 
 which go back to supply the muscles in the spinal fossae, and 
 also to send twigs into the spinal canal through the inter- 
 vertebral foramina. After giving off the posterior branches, 
 they pass forwards along the lower borders of the ribs, occu- 
 pying the intercostal grooves. Each artery divides into two 
 or more branches, some distance from the sternum, which 
 anastomose with branches from the internal mammary. 
 They are accompanied by the intercostal nerves in the inter- 
 costal spaces, and also the veins of the same name. 
 
 The THORACIC DUCT, Fig. 141 (i 2, i s, \ 4), was seen in the 
 posterior mediastinum, and was also noticed in the dissection 
 of the neck. It commences in the receptaculum chyti, which 
 is situated on the second lumbar vertebra, and between the 
 right or long crus of the diaphragm and the aorta. It enters 
 the posterior mediastinum through the aortic opening in the 
 diaphragm, between the aorta and azygos vein, and ascends 
 nearly in a straight direction as far as the third cervical 
 vertebra, having the oesophagus in front of it ; it now turns 
 to the left beneath the aorta, and gets to the left side of the 
 
 28* 
 
330 DISSECTION OF THE THORAX. 
 
 oesophagus and to the inner side of the subclavian artery, and 
 passes up in this direction to the fifth cervical vertebra, 
 where it curves forwards and outwards to join the subcla- 
 vian vein at its junction with the internal jugular. 
 
 In passing through the thorax, it not unfrequently divides 
 into two or three trunks, which again unite into one trunk 
 before its termination; sometimes it terminates in two or 
 three divisions, which have separate openings into the sub- 
 clavian vein. It is the common trunk of the lymphatics of 
 the whole body, except the right half of the head and 
 neck, and the right upper extremity. The lymphatics of 
 these parts terminate in the right thoracic duct, Fig. 141 (i s), 
 which opens into the right subclavian at its union with the 
 internal jugular vein. 
 
 The YENA AZYGOS MAJOR, Fig. 141 (10), commences in 
 the abdomen near the second lumbar vertebra, and on the 
 right side. It is formed by the union of branches from 
 several veins, as the superior lumbar, renal, and capsu- 
 lar. Sometimes it communicates directly with the ascending 
 cava. It passes through the aortic opening in the diaphragm, 
 and ascends on the bodies of the vertebrae as far as the fourth 
 dorsal, where it curves forwards over the upper border of the 
 root of the lung to enter the descending cava. It crosses over 
 the intercostal arteries. It receives in the thorax the right 
 intercostal veins, except the upper one or two, the vena azy- 
 gos minor, the oesophageal, mediastinal and bronchial veins. 
 
 The YENA AZYGOS MINOR, Fig. 141 (i i), commences in 
 the lumbar region, on the left side, in a similar manner to 
 that of the azygos major on the right side. It passes 
 through the left crus of the diaphragm, usually with the left 
 great splanchnic nerve, and ascends on the left side of the 
 vertebral column, as far as the sixth or seventh dorsal verte- 
 bra, where it passes over to the right side to join the vena 
 azygos major; it crosses beneath the aorta and thoracic duct. 
 It receives the inferior six or seven left intercostal veins, 
 also, the oesophageal, phrenic, and mediastinal veins. 
 
 The upper five or six intercostal veins, except the first 
 on the left side, unite to form a common trunk, which is some- 
 times called the superior vena azygos it empties into one of 
 the other azygos veins. The left superior intercostal gene- 
 rally joins the vena trans versa. The intercostal veins receive 
 branches through the inter vertebral foramina from the 
 
SYMPATHETIC NERVE. 
 
 331 
 
 spinal canal, and also from the muscles in the spinal 
 fossse on the back. By means of the azygos veins, a commu- 
 nication is established between the two vense cavse. These 
 veins are not supplied with valves, so that the blood may 
 pass from one cava to the other in either direction. 
 
 The SYMPATHETIC NERVE may Fig. 141. 
 
 be seen in the thorax on each side 
 of the vertebral column without 
 any dissection. It consists of twelve 
 ganglia on each side, and branches 
 proceeding from them. The ganglia 
 are situated near the heads of the 
 ribs, and are covered by the pleura 
 and a thin fascia. The first, second, 
 and twelfth, are larger than the 
 intermediate ones. The first is 
 connected to the third cervical 
 ganglion by filaments, which pass 
 round the subclavian artery ; some- 
 times the two ganglia are joined to 
 each other. The twelfth is joined 
 by filaments to the first lumbar. 
 
 The ganglia are also connected 
 to each other by filaments. Their 
 branches are external and internal. 
 The external connect the ganglia 
 with the intercostal nerves. They 
 consist of two sets of fibres, deep 
 and superficial. They resemble the 
 spinal nerves in their appearance. 
 The internal branches are distrib- 
 uted in the mediastinal space, and 
 in the abdomen. Those from the 
 upper five or six ganglia pass in- 
 
 A VIEW OP THE COURSE AND TERMINATION OF THE THORACIC DUCT. 1. Arch of 
 the aorta. 2. Thoracic aorta. 3. Abdominal aorta. 4. Arteria innoininata. 5. 
 Left carotid. 6. Left subclavian. 7. Superior cava. 8. The two venae innominate. 
 9. The internal jugular and subclavian vein at each side. 10. The vena azygos. 
 11. The termination of the vena azygos minor in the vena azygos. 12. The recep- 
 taculum chyli : several lymphatic trunks are seen opening into it. 13. The thoracic 
 duct dividing, opposite the middle dorsal vertebrae, into two branches, which soon 
 reunite; the course of the duct behind the arch of the aorta and left subclavian 
 artery is shown by a dotted line. 14. The duct making its turn at the root of the 
 neck and receiving several lymphatic trunks previous to terminating in the poste- 
 rior angle of the junction of the internal jugular and subclavian veins. 15. The 
 termination of the trunk of the lymphatics of the upper extremity. 
 
332 
 
 DISSECTION OF THE THORAX. 
 
 wards along the intercostal arteries, and are lost principally 
 on the aorta ; some filaments go to the bodies of the verte- 
 bras, and to the pulmonary plexus of the same side. 
 
 Fig. 142. 
 
 A VIEW OF THE GREAT 
 SYMPATHETIC NERVE. l.The 
 plexus on the carotid artery 
 in the carotid foramen. 2. 
 Sixth nerve (motor externus). 
 3. First branch of the fifth 
 or ophthalmic nerve. 4. A 
 branch on the septum narium 
 going to the incisive foramen. 
 
 5. The recurrent branch, or 
 Vidian nerve divided into the 
 carotid and petrosal branches. 
 
 6. Posterior palatine branches. 
 
 7. The lingual nerve joined 
 by the chorda tympani. 8. 
 The portiodura of the seventh 
 pair or the facial nerve. 9. 
 The superior cervical gan- 
 glion. 10. The middle cervical 
 ganglion. 11. The inferior 
 cervical ganglion. 12. The 
 roots of the great splanchnic 
 nerve arising from the dorsal 
 ganglia. 13. The lesser splan- 
 chnic nerve. 14. The renal 
 plexus. 15. The solar plexus. 
 16. The mesenteric plexus. 17. 
 The lumbar ganglia. 18. The 
 sacral ganglia. 19. The vesi- 
 cal plexus. 20. The rectal 
 plexus. 21. The lumbar plex- 
 us (cerebro-spinal). 22. The 
 rectum. 23. The bladder. 
 24. The pubis. 25. The crest 
 of the ilium. 26. The kidney. 
 27. The aorta. 28. The dia- 
 phragm. 29. The heart. 30. 
 The larynx. 31. The sub- 
 maxillary gland. 32. The 
 incisor teeth. 33. Nasal sep- 
 tum. 34. Globe of the eye. 
 35, 36. Cavity of the cra- 
 nium. 
 
SYMPATHETIC NERVE. 333 
 
 Branches from the sixth or seventh, and the eighth, ninth, 
 and tenth ganglia on each side, pass downwards and forwards 
 on the sides of the vertebrae to the lower part of the pos- 
 terior mediastinum, where they unite into one cord called 
 the great splanchnic nerve, Fig. 142 (12), which perforates the 
 diaphragm to reach the semilunar ganglion, on the side of 
 the coeliac artery. Sometimes it passes through the aortic 
 opening. 
 
 The lesser splanchnic nerve on each side, Fig. 142 (is), is 
 formed by branches from the eleventh and twelfth ganglia ; 
 it passes through the crus of the diaphragm, and joins the 
 solar plexus. A third splanchnic nerve sometimes arises 
 from the twelfth ganglion, enters the abdomen, and goes to 
 the renal plexus. 
 
 The cardiac nerves and ganglion cannot well be dissected in 
 the thorax, until the student has acquired a knowledge of the 
 contents of the superior mediastinum. For this purpose two 
 subjects will be required ; one for the viscera, and another 
 for the nerves. The frequent variation met with in the 
 arrangement of the cardiac nerves renders the study of them 
 more or less unsatisfactory. They are derived principally 
 from three sources, the cervical ganglia, the pneumogastric, 
 and the recurrent nerves. Those from the cervical ganglia 
 are named the superior, middle, and inferior cardiac. These in 
 their course are joined by filaments from the recurrent and 
 pneumogastric. They all terminate in the cardiac plexuses, 
 from which filaments proceed to form the coronary plexuses 
 on the heart. 
 
 The superior cardiac nerve on each side arises, usually, from 
 the first cervical ganglion, passes down the neck behind the 
 sheath of the carotid artery, and enters the thorax behind the 
 subclavian; sometimes it crosses over the artery. In the 
 thorax, it accompanies the arteria innomiriata on the right 
 side to its origin, where it divides into two sets of filaments; 
 one set passes in front of the aorta to reach the superficial 
 cardiac plexus, while the other passes behind it to join the 
 deep or great cardiac plexus. In its course in the thorax, it is 
 joined by filaments from the recurrent, and the middle and 
 inferior cardiac nerves. 
 
 The middle cardiac nerve arises from the middle cervical 
 ganglion, or it may arise from the cord of the sympathetic, 
 descends behind the carotid, and enters the thorax either be- 
 
334 DISSECTION OF THE THORAX. 
 
 hind or in front of the subclavian artery. In the thorax, its 
 course is similar to that of the superior cardiac. It also re- 
 ceives filaments from the pneumogastric and recurrent nerves. 
 It is generally the largest of the three cardiac nerves. 
 
 The inferior cardiac nerve arises from the third cervical 
 ganglion, and passes down behind the arteria innominata and 
 aorta, and terminates in the deep cardiac plexus. It receives 
 branches from the pneumogastric and recurrent. 
 
 The cardiac ganglion is situated between the arch of 
 the aorta and pulmonary artery, on the right side of the 
 remains of the ductus arteriosus. It receives filaments from 
 the superior cardiac nerves, and also from the pneumogas- 
 tric. These filaments form the superficial cardiac plexus, from 
 which filaments, together with others derived from the deep 
 cardiac plexus, proceed downwards to form a plexus which 
 accompanies the right coronary artery on the heart. 
 
 The deep cardiac plexus is formed by filaments from the 
 superior cardiac nerves, more from the right than from the 
 left, by the middle and inferior cardiac nerves, and filaments 
 from the pneumogastric and recurrent. It is situated above 
 the pulmonary artery, and between the arch of the aorta and 
 the trachea ; a portion of it is also situated between the right 
 pulmonary artery and the bifurcation of the trachea. From 
 this plexus some filaments pass in front of the pulmonary 
 artery, to join others from the superficial plexus. The greater 
 portion of them, however, pass down behind and between 
 this artery and the aorta, to form a plexus, which accom- 
 panies the left coronary artery. Some filaments from this 
 plexus also join the pneumogastric nerves, and with them go 
 to the lungs. 
 
 DISSECTION OF THE LIGAMENTS OF THE TIIOEAX. 
 
 The true ribs are joined to the sternum directly by cartilages, 
 while the false ribs are connected to it indirectly by their car- 
 tilages joining those of the true ribs. The sternal extremities 
 of the ribs are excavated, and the cartilages are received into 
 them, while the sternal ends of the cartilages of the true ribs 
 are rounded, and received into concavities on the borders of 
 the sternum. Synovial membranes are found between these 
 cartilages and the sternum, except the first. They are con- 
 
LIGAMENTS OF THE THORAX. 
 
 335 
 
 Fig. 143. 
 
 nected to the sternum by ligamentous fibres, Fig. 143 (5), 
 which surround the articulations and spread out on the sur- 
 faces of that bone. They add very much to the strength of 
 the bone, which, indeed, is 
 covered on both sides by 
 strong ligamentous bands. 
 
 It will be convenient to 
 examine, at this time, the 
 ligaments which join the 
 clavicles to the first ribs, to 
 the sternum, and to each 
 other. 
 
 The clavicle, on each side, 
 is connected to the first rib 
 by a single ligament, named 
 
 the COSTO-CLAVICULAK, or 
 
 the RHOMBOID, Fig. 143 (3). 
 It arises from the lower 
 border of the clavicle, close 
 to the sternum, and is in- 
 serted into the cartilage of 
 the first rib. Its direction 
 is inwards and forwards. 
 The clavicle is joined to 
 
 THE LIGAMENTS OF THE STERNO-CLAVI- 
 CULAR AND COSTO-STERNAL ARTICULA- 
 TIONS. 1. The anterior stern o-clavicular 
 ligament. 2. The interclavicular liga- 
 ment. 3. The costo-clavieular, or rhom- 
 boid ligament, is seen on both sides. 4. The 
 interarticular fibro-cartilage, brought into 
 view by the removal of the anterior and 
 posterior ligaments. 5. The anterior costo- 
 sternal ligaments of the first and second 
 ribs. 
 
 the sternum by ligamentous 
 
 fibres, which wholly surround the joint. They are sometimes 
 designated the ANTERIOR and POSTERIOR STERNO-CLAVICULAR 
 LIGAMENTS, Fig. 143 (i), but there is no distinct line of sepa- 
 ration between them. They form a sort of capsular ligament. 
 
 This joint is usually divided into two cavities by an INTER- 
 ARTICULAR FIBRO-CARTILAGE, Fig. 14^4), and contains two 
 distinct synovial sacs. The fibro-cartilage is attached to the 
 clavicle above, to the sternum below, and to the sterno-cla- 
 vicular ligaments, anteriorly and posteriorly. It adds con- 
 siderably to the strength of the joint. 
 
 The two clavicles are connected together by an INTERCLA- 
 VICULAR LIGAMENT, Fig. 143 (2), which stretches across the 
 sigmoid notch at the upper extremity of the sternum, the 
 depth of which is, by means of it, somewhat diminished. 
 
 All the ribs are joined directly to the vertebrse behind. 
 With the exception of the first and the two last, each rib 
 articulates, by its head, with the bodies of two contiguous 
 
836 
 
 DISSECTION OF THE THORAX. 
 
 vertebrae and their intervertebral substance. The ribs are 
 also joined, by their tubercles, to the transverse processes of 
 the vertebrae. 
 
 The head of each rib is connected to two bodies of the 
 vertebrae and the intervertebral substance, by an ANTERIOR 
 
 COSTO-VERTEBRAL, Or STELLATE LIGAMENT, Fig. 144 (2), and an 
 
 INTEROSSEOUS LIGAMENT, Fig. 144 (4). Theirs*! arises from 
 
 Fig. 144. 
 
 Fig. 145. 
 
 THE ANTERIOR LIGAMENTS OF THE VER- 
 TEBRA, AND THE LIGAMENTS OP THE RIBS. 
 1. The anterior common ligament. 2. 
 The anterior costo-vertebral, or stellate 
 ligament. ^. The anterior costo-transverse 
 ligament. 4. The interosseous ligament 
 connecting the head of the rib to the 
 intervertebral substance, and separating 
 the two synovial membranes of this arti- 
 culation. 
 
 A POSTERIOR VIEW OF A PART 
 OF THE THORACIC PORTION OF THE 
 VERTEBRAL COLUMN, SHOWING THE 
 LIGAMENTS CONNECTING THE VER- 
 TEBRA WITH EACH OTHER. AND THE 
 
 RIBS WITH THE VERTEBRAE. 1, 1. 
 The supra-spinous ligament. 2, 2. 
 The ligamenta subflava, connecting 
 the laminae. 3. The anterior costo- 
 transverse ligament. 4. The pos- 
 terior costo-transverse ligaments. 
 
 the head of the rib in front, and is inserted, by three fasciculi, 
 into the bodies of the vertebrae and the intermediate substance. 
 The second arises from the angle between the facets on the 
 Lead of the rib, and is inserted into the intervertebral sub- 
 stance. The first and the two last ribs have no interosseous 
 ligaments, and, consequently, each one has but a single syno- 
 vial sac, while each of the others have two. 
 
 The ribs are connected to the transverse processes by three 
 ligaments, viz : The anterior, or internal costo-transverse, the 
 posterior, or external costo-transverse, and the middle costo- 
 transverse, or interosseous ligament. A small synovial sac 
 
LIGAMENTS OF THE THORAX. 337 
 
 is found between the tubercles of the ribs and the transverse 
 processes. 
 
 The INTERNAL COSTO-TRANSVERSE LIGAMENT, Fig. 145 
 (3), arises from the inferior border of the transverse process, 
 passes obliquely downwards, and is inserted into the neck 
 of the rib immediately below. This ligament is absent in the 
 articulation of the .first rib. 
 
 The EXTERNAL COSTO-TRANSVERSE LIGAMENT, Fig. 145 
 (4), extends obliquely from the apex of the transverse process 
 to the tubercle of the rib. 
 
 The MIDDLE COSTO-TRANSVERSE, or INTEROSSEOUS LIGA- 
 MENT, passes from the transverse process directly to the pos- 
 terior part of the cervix of the rib. Its fibres are usually 
 intermixed with more or less adipose tissue, and cannot be 
 distinctly seen without making a section of the rib. 
 
 29 
 
PART III. 
 
 DISSECTION OF ABDOMEN AND LOWER EXTREMITIES. 
 
 \ 
 
 CHAPTEK I. 
 
 OF THE ABDOMEN. 
 
 SECT. I. PAEIETES OF THE ABDOMEN. 
 
 To dissect the parietes of the abdomen, the subject must 
 be laid on the back, and elevated sufficiently, by means of 
 one or more blocks placed beneath it, to render the muscles 
 tense. The amount of elevation required will depend very 
 much on the fulness of the abdomen, and must be deter- 
 mined by the dissector in each case. 
 
 The extent of the integument to be incised in this dissec- 
 tion is indicated by the outlines of the external oblique 
 muscle. If the student should wish to study the superficial 
 fascia and the cutaneous vessels and nerves, it is immaterial 
 how he makes his incisions for the purpose of removing 
 the skin, as his object will be merely to uncover the fascia 
 so as not to injure the vessels and nerves which ramify in 
 it. But if his object be to raise the fascia with the skin, 
 the incisions should be made with reference to the dissection 
 of the external oblique muscle. 
 
 As the fibres of this muscle are directed from above 
 downwards and forwards, the integument must be raised so 
 as to admit of exposing the muscle by cutting in the direc- 
 tion of its fibres. If this rule be disregarded, and the student 
 attempts to expose the muscle by cutting across the fibres, 
 his dissection will necessarily be rough and unsatisfactory. 
 Whether the skin be raised separately or with the fascia, it 
 is often convenient to leave the inguinal region untouched 
 for the purpose of making a special dissection of the parts 
 
340 OF THE ABDOMEN. 
 
 concerned in inguinal hernia. In this case, the dissection of 
 the skin and fascia may be carried down only to a line ex- 
 tending transversely across from the anterior superior spinous 
 process of the ilium to the linea alba. The student will find 
 the parts in the inguinal region described in the first place 
 simply as forming a portion of the abdominal parietes, and 
 afterwards with special reference to hernia. If he can dissect 
 the lower extremity but once during the session, he had better 
 reserve the inguinal region for a special dissection. 
 
 Make an incision from the xiphoid or ensiform cartilage 
 down to the symphysis pubis along the linea alba ; and an- 
 other corresponding to the origin of the external oblique 
 muscle. The last incision will extend laterally from the first 
 over the lower eight ribs, and about three or four inches 
 above the inferior border of the most prominent part of the 
 thorax. If the pectoralis major and serratus anticus muscles 
 have been previously dissected, this incision will not be re- 
 quired ; if they have not been, the incision should be made 
 so as to expose those portions of them which are in relation 
 with the external oblique. 
 
 Instead of making an incision over the origin of the ex- 
 ternal oblique, the student may make one, commencing just 
 above the umbilicus, and extending obliquely upwards and 
 outwards, in the direction of the fibres of the external oblique, 
 and then raise the integument in two flaps, one to be reflected 
 upwards, and the other downwards. The advantage of this 
 mode of procedure is that the external oblique is much 
 thicker and its fibres more distinct in the line of this incision 
 than it is in the upper part, where its fibres are short and 
 comparatively few in number, and its aponeurosis is thin and 
 liable to be cut through, thus exposing the rectus abdominis 
 muscle. 
 
 When the student has once obtained a distinct view of the 
 fibres or fasciculi of a muscle, in whatever part of it, he can 
 have no difficulty in dissecting it as long as he is careful to 
 follow its fibres. In order to do this, he must take sufficient 
 . time to remove the fascia entirely from every fasciculus as he 
 proceeds in the dissection. 
 
 The SUPERFICIAL FASCIA of the abdomen is continuous 
 above with the fascia of the thorax, and below with that of 
 the pelvis and lower extremity. In the upper and lateral 
 
PARIETES OF THE ABDOMEN. 341 
 
 parts of the abdomen it is thin, and requires no special notice. 
 Over the linea alba it is thicker and more compact. Around 
 the umbilicus it is dense, and seems to be blended with the 
 tendon underneath. At the lower part of the linea alba it 
 usually contains fibrous fasciculi, which go down to the dorsum 
 of the penis; they constitute the suspensory ligament of that 
 organ. It is prolonged round the spermatic cord into the 
 scrotum, where it joins the superficial perineal fascia, and 
 forms separate pouches for the testicles. 
 
 In the inguinal region it is divided into a deep and super- 
 ficial layer. The former is much more dense and compact 
 than the latter; it is adherent to Poupart's ligament, and 
 appears to be continuous with the fascia lata in the upper 
 part of the thigh ; a short distance above Poupart's ligament 
 it is blended with the tendon of the external oblique. This 
 lamina has been called the fascia of Scarpa. The outer layer 
 of the superficial fascia is areolar, and usually contains adi- 
 pose substance in this region ; hence, it is sometimes called 
 the adipose layer ; the inner layer is more compact, and con- 
 tains yellow elastic tissue, which assists the muscles in sup- 
 porting the abdominal viscera. 
 
 The CUTANEOUS ARTERIES of the abdomen are derived 
 from the internal mammary, the intercostal, the lumbar, the 
 femoral, and the external iliac. The only one of any import- 
 ance to be studied is the arteria ad cutem abdominis. This 
 arises from the femoral artery a short distance below Pou- 
 part's ligament, and passes upwards in the superficial fascia 
 nearly to the umbilicus. It varies in size, but is rarely absent. 
 
 The CUTANEOUS NERVES consist of branches of the lower 
 five or six intercostals and the lumbar. There are two sets 
 of the cutaneous branches of the intercostals, the lateral and 
 the anterior. The former are given off in the intercostal 
 spaces, perforate the muscles, and divide into anterior and 
 posterior filaments; the latter are the terminal branches of 
 the intercostals, which, after leaving the intercostal spaces, 
 pass forwards to the sheath of the rectus abdominis, which, 
 together with the muscle, they perforate to reach the integu- 
 ment near the linea alba. The remaining cutaneous nerves 
 are derived from branches of the lumbar plextis, and are dis- 
 tributed in the lower part of the abdomen. 
 
 There are five pairs of muscles in the anterior and lateral 
 
 29* 
 
342 OF THE ABDOMEN. 
 
 parietes of the abdomen. They are the external and internal 
 oblique, the transverse, the recti, and the pyramidal. To 
 render these muscles tense for dissection, besides using blocks, 
 it may sometimes be found convenient to distend the bowels 
 either by inflation or by injecting water into them. 
 
 The OBLIQUUS EXTERNUS, Fig. 146 (12, is), lies next to 
 the superficial fascia. It arises from the eight inferior ribs 
 near their cartilages, by as many fleshy digitations. These 
 digitations project in between five similar ones belonging to 
 the serratus anticus, and three belonging to the latissimus 
 dorsi. It requires some care in dissecting to make these 
 digitations distinct. A slip extends from the upper part to 
 the pectoralis major. The length and direction of the fibres 
 vary in different parts of the muscle. In the upper part they 
 are short and quite oblique, in the middle they are longer 
 but less oblique, while they are nearly perpendicular in the 
 posterior part. 
 
 The upper and middle fibres terminate in a broad aponeu- 
 rotic tendon, which is inserted into the ensiform cartilage, the 
 linea alba, the pubic bone, and Poupart's ligament ; the pos- 
 terior fibres are inserted tendinous and fleshy into the anterior 
 two thirds of the crest of the ilium. The student should be 
 careful to observe where the muscular fibres join the tendon, 
 so that he may avoid cutting through it. 
 
 POUPART'S LIGAMENT, Fig. 146 (14), is regarded by some 
 as the lower border of the tendon of the external oblique 
 folded back upon itself. By others it is considered as consist- 
 ing of fibres which arise from the anterior superior spinous 
 process of the ilium, and extending across the crural region, 
 are inserted into the spine and crest of the pubic bone. That 
 portion of it which is inserted into the crest of the pubis is 
 called Gimbernafs ligament. 
 
 The external oblique muscle is capable of acting in several 
 ways. If the thorax and pelvis be fixed and both muscles 
 act, they will compress the abdominal viscera ; if the thorax 
 be fixed, they will approximate the pelvis to it, or if the 
 pelvis be stationary, they will draw the thorax forwards. If 
 one acts separately, it will rotate the thorax to the opposite 
 side, or the pelvis to its own side, or approximate them in a 
 lateral direction. Before dissecting up the external oblique, 
 the following points should be observed : 
 
PAKIETES OF THE ABDOMEN, 
 
 Fig. 146. 
 
 .\ 
 
 343 
 
 THE MUSCLES OF THE ANTERIOR ASPECT OP THE TRUNK; ON THE LEFT SIDE 
 THE SUPERFICIAL LAYER is SEEN, AND ON THE RIGHT THE DEEPER LAYER. 1. 
 The pectoralis major muscle. 2. The deltoid; the interval between these muscles 
 lodges the cephalic vein. 3. The anterior border of the latissimus dorsi. 4. The 
 serrations of the serratus magnus. 5. The subclavius muscle of the right side. 6. 
 The pectoralis minor. 7. The coraco-brachialis muscle. 8. The upper part of the 
 biceps muscle, showing its two heads. 9. The coracoid process of the scapula. 10. 
 The serratus magnus of the right side. 11. The external intercostal muscle of the 
 fifth intercostal space. 12. The external oblique muscle. 13. Its aponeurosis; the 
 median line to the right of this number is the linea alba; the flexuous line to its 
 left is the linea semilunaris; and the transverse lines above and below the number, 
 the lineag transversae. 14. Poupart's ligament. 15. The external abdominal ring; 
 the margin above the ring is the superior or internal pillar; the margin below the 
 ring, the inferior or external pillar; the curved intercolmnnar fibres are seen pro- 
 ceeding upwards from Poupart's ligament to strengthen the ring. The numbers 14 
 and 15 are situated upon the fascia lata of the thigh : the opening immediately to 
 the right of 15 is the saphenous opening. 16. The rectus muscle of the right side 
 brought into view by the removal of the anterior segment of its sheath : # the pos- 
 terior segment of its sheath with the divided edge of the anterior segment. 17. 
 The pyramidalis muscle. 18. The internal oblique muscle. 19. The conjoined 
 tendon of the internal oblique and transversalis descending behind Poupart's liga- 
 ment to the pectineal line. 20. The arch formed between the lower curved border 
 of the internal oblique muscle and Poupart's ligament; it is beneath this arch that 
 the spermatic cord and hernia pass. 
 
344 OF THE ABDOMEN. 
 
 The LINEA ALBA, Fig. 146 (i s), is a white line extending 
 from the symphysis pubis to the xiphoid cartilage. It occu- 
 pies the space between the recti muscles, and is formed by 
 a blending of the tendinous fibres of the broad muscles of the 
 abdomen in the median line. Its breadth increases from 
 below upwards. In pregnancy and dropsies of the abdomen, 
 it sometimes acquires a greatly increased breadth. The 
 umbilicus is situated nearly in its centre. This consists of a 
 dense ligamentous substance, to which the integument adheres 
 very closely. It is the remains of the umbilical vein and 
 arteries of the foetus. When it is necessary to cut into the 
 abdominal cavity, as in the high operation of lithotomy, and 
 in gastrotomy, or to puncture the parietes, as in ascites, it 
 is generally done through the linea alba. 
 
 The LINEA SEMILUNARIS, Fig. 146 (i 3), is a white line situ- 
 ated along the external border of each of the recti muscles. 
 It is caused by the absence of muscular fibres in this portion 
 of the abdominal parietes. 
 
 The LINEJE TRANSVERSE, Fig. 146 (i 3), extend from the 
 linea semilunaris to the linea alba. There are usually four 
 or five of them on each side. They are produced by tendin- 
 ous intersections in the recti muscles. 
 
 The EXTERNAL ABDOMINAL KING, Fig. 146 (is), is an 
 opening in the tendon of the external oblique muscle, situated 
 just above the spine of the pubis. It transmits the spermatic 
 cord in the male, and the round ligament in the female. A 
 fascia is reflected from its margin down over the spermatic cord. 
 This opening and the parts around will be examined in the 
 dissection of the inguinal region with reference to hernia. 
 
 The tendon of the external oblique is perforated by nume- 
 rous small foramina for the transmission of the cutaneous 
 vessels and nerves. The external oblique may be raised by 
 detaching it from the ribs and the crest of the ilium, and also 
 from Poupart's ligament, if it be not desired to preserve the 
 parts in the inguinal region for a special dissection ; in the 
 latter case the tendon may be divided by an incision extend- 
 ing from the anterior superior spinous process of the ilium 
 transversely across to the linea alba. It is sometimes con- 
 venient, as when the subject cannot well be turned partly on 
 one side, to raise this muscle by making an incision through 
 
PARIETES OF THE ABDOMEN. 345 
 
 it from near the origin of its upper head, obliquely down- 
 wards to the anterior superior spinous process of the ilium, 
 nearly in the direction of the fibres of the internal oblique 
 muscle, and then turning one flap forwards, and the other 
 backwards, detach it from the ribs and the crest of the ilium 
 as the dissection proceeds. Whichever mode is adopted, the 
 fascia which separates it from the internal oblique should be 
 dissected up with it. 
 
 The OBLIQUUS INTERNUS, Fig. 146 (i s), has an extensive 
 origin and a more extensive insertion. It arises from the 
 fascia lumborum, the crest of the ilium, and the external two- 
 thirds of Poupart's ligament. Its fibres diverge so as to 
 be inserted into the lower five or six ribs, the xiphoid carti- 
 lage, the linea alba, the symphysis pubis, the body of the 
 pubic bone, and the linea pectinea. The posterior fibres 
 ascend obliquely to the ribs, and the upper part of the linea 
 alba ; the middle have a transverse direction, while the ante- 
 rior pass forwards and downwards, some to the lower part of 
 the linea alba, others to the body of the pubis and the linea 
 pectinea. It will be observed that while all the lower and 
 anterior part of the external oblique, to the outer side of the 
 rectus muscle, is aponeurotic, the corresponding portion of 
 the internal oblique is muscular, and that in the upper and 
 anterior part the reverse is true. 
 
 The tendon of the internal oblique, above a point midway 
 between the umbilicus and symphysis pubis, divides into two 
 layers, the anterior of which passes in front of the rectus, and 
 unites with the tendon of the external oblique about three- 
 fourths of an inch outside of the linea alba, while the posterior 
 layer passes behind the rectus and joins the tendon of the 
 transversalis muscle. The anterior layer extends higher up 
 in front of the rectus than the posterior does behind it. The 
 lower part of the tendon does not split, but the whole of it 
 passes in front of the rectus. The lowest portion of the 
 tendon unites with the corresponding portion of the tendon 
 of the transversalis, to form the conjoined tendon, Fig. 146 
 (i 9), of these two muscles. That part of the conjoined ten- 
 don which is inserted into the linea pectinea is placed directly 
 behind the external abdominal ring, and, as will be seen in 
 the dissection of the inguinal region, forms an important part 
 in the anatomy of direct inguinal hernia. 
 
346 OF THE ABDOMEN. 
 
 As no fibres arise from the inner third of Poupart's liga- 
 ment, there is left a space, Fig. 147 (i i), between it and the 
 lower border of the muscle for the passage of the spermatic 
 cord. 
 
 The action of the internal oblique muscle is similar in 
 some respects to that of the external oblique. When both 
 act at the same time, they will compress the abdominal viscera, 
 or approximate the thorax and pelvis. When one acts alone, 
 or in conjunction with the external oblique of the opposite 
 side, it will rotate either the thorax or the pelvis to its own 
 side; or if it acts with the external oblique of the same side, 
 it will bend the thorax to that side, or draw the pelvis up. 
 
 The CREMASTEK MUSCLE, which arises from Poupart's 
 ligament, in common with the lower fibres of the internal 
 oblique, is found in the outer and anterior part of the space 
 just named. This muscle accompanies the spermatic cord 
 through the external abdominal ring, and down into the 
 scrotum, where it forms loops on the tunica vaginalis ; its 
 fibres then ascend on the cord, and are inserted into the 
 linea pectinea. Some of its fibres are usually lost on the 
 tunica vaginalis. 
 
 The fibres of the cremaster are frequently very pale and 
 few in number, so that some care is required to separate 
 them from the cord. Its use is to draw up and support the 
 testicle. 
 
 In raising the internal oblique muscle, the student will 
 sometimes experience some difficulty in finding the separation 
 between it and the transversalis muscle. This may be done 
 most readily by dividing its fibres near the anterior portion 
 of the crest of the ilium, where the two muscles are separated 
 by the internal circumflex ilii artery. When the separation 
 is once found, it is comparatively easy to follow it, especially 
 in the upper and posterior part, where the direction of the 
 fibres is different. The lower part of the muscle is closely 
 connected to the transversalis, and it requires some care to 
 separate them. 
 
 The TEANSVEKSALIS, Fig. 147 (e, 7, s, 9), arises from the 
 fascia lumborum, the crest of the ilium, the external half of 
 Poupart's ligament, and the lower six or seven ribs, where 
 it indigitates with the diaphragm. All its fibres, with the 
 exception of the lower, or those which arise from Poupart's 
 
PAEIETES OF THE ABDOMEN. 
 
 347 
 
 ligament, have a transverse direction, and are inserted into 
 the linea alba. The lower fibres pass forwards and down- 
 Fig. 147. 
 
 A LATERAL VIEW or THE TRUNK OP 
 
 THE BODY, SHOWING ITS MUSCLES, AND 
 PARTICULARLY THE TRANSVERSALIS AB- 
 
 DOMINIS. 1. The costal origin of the 
 latissirnus dorsi muscle. 2. The serratus 
 magnus. 3. The upper part of the ex- 
 ternal oblique muscle, divided in the 
 direction best calculated to show the 
 muscles beneath, without interfering 
 with its indigitations with the serratus 
 magnus. 4. Two of the external inter- 
 costal muscles. 5. Two of the internal 
 intercostals. 6. The transversalis mus- 
 cle. 7. Its posterior aponeurosis. 8. 
 Its anterior aponeurosis, forming the 
 most posterior layer of the sheath of the 
 rectus. 9. The lower part of the left 
 rectus, with the aponeurosis of the trans- 
 versalis passing in front. 10. The right 
 rectus muscle. 11. The arched opening 
 left between the lower border of the 
 transversalis muscle and Poupart's liga- 
 ment, through which the spermatic cord 
 and hernia pass. 12. The glutaeus maxi- 
 mus, and medius, and tensor vaginas 
 femoris muscles invested by fascia lata. 
 
 wards, and are inserted into the lower part of the linea alba, 
 the body of the pubis and the linea pectinea, forming with 
 the internal oblique, the conjoined tendon of the internal oblique 
 and transversalis. The tendon of this muscle is applied to 
 the posterior surface of that of the internal oblique, with 
 which it passes both behind and in front of the rectus. The 
 upper and anterior part of the transversalis is muscular,, 
 where the corresponding part of the internal oblique is ten-, 
 dinous. Its principal use is that of a compressor of the 
 viscera of the abdomen. 
 
 The fascia lumborum is described in connection with the 
 muscles of the back, and should be studied when they are 
 dissected. The internal oblique and transversalis muscles 
 are sometimes described as arising directly from the vertebrae- 
 
34:8 OF THE ABDOMEN. 
 
 the former from the spinous, and the latter from the trans- 
 verse processes of the lumbar vertebrae. 
 
 To expose the rectus, make an incision through the tendon 
 of the external oblique and the anterior lamina of the internal 
 oblique, from the cartilage of the sixth rib to the pubis, 
 about three-fourths of an inch from the linea alba, and paral- 
 lel with it ; then dissect these tendons up from the muscle, 
 turning one flap inwards and the other outwards. At the 
 lower part of the rectus the incision will extend through the 
 tendons of the three broad muscles, as they all pass in front 
 of that muscle. They are easily separated from the muscle, 
 except at the linae transversas, where they are blended with 
 the tendinous intersections, from which it will require some 
 care to detach them. After exposing the muscle in this way, 
 divide it opposite the umbilicus, and reflect one portion up- 
 wards and the other downwards, when its relations to the 
 tendons of the broad muscles may be examined ; branches of 
 the epigastric and internal mammary arteries, and of the inter- 
 costal nerves, will be seen penetrating it from behind. The 
 termination below of the posterior lamina of the tendon of 
 the internal oblique, and the tendon of the trans versalis, will 
 be observed. They generally present quite a distinct semi- 
 lunated border, but not always. The tendinous intersections 
 are very imperfect behind, and do not usually adhere to the 
 sheath of the rectus. 
 
 The KECTUS, Fig. 146 (i e), arises from the upper border 
 of the os pubis, between the spine and symphysis, by a flat 
 tendon. It passes upwards on the side of the linea alba, 
 gradually increasing in breadth but diminishing in thick- 
 ness, until it reaches the thorax. It is inserted into the car- 
 tilages of the fifth, sixth, and seventh ribs, and sometimes 
 into the xiphoid or ensiform cartilage. 
 
 The fibres are interrupted in their course by the linem 
 transverse ; one of which is placed opposite to the ensiform 
 cartilage, one between this and the umbilicus, one at the 
 umbilicus, and another lower down. Each presents a zigzag 
 line, and only two of them, the one at the ensiform cartilage 
 and the one at the umbilicus, extend entirely across the 
 muscle. The rectus draws the thorax towards the pelvis or 
 the pelvis towards the thorax ; it also acts as a compressor. 
 The tendinous intersections connect it with the tendons of 
 
ANATOMY OF INGUINAL HERNIA. 349 
 
 the broad muscles, and also, when it contracts, prevent its 
 bulging so much as it would if its fibres extended the whole 
 length of the muscle ; they may, perhaps, augment somewhat 
 its power to act. 
 
 The PYRAMIDALIS, Fig. 146 (17), arises from the upper 
 surface of the body of the pubic bone, anterior to the rectus. 
 It passes upwards, and is inserted into the linea alba two or 
 three inches above the symphysis pubis. It is of a trian- 
 gular shape, and usually placed in a sheath, formed by a 
 splitting of the conjoined tendon of the internal oblique and 
 transversalis. It is sometimes absent. The pyramidalis acts 
 on the linea alba in a vertical direction. 
 
 ANATOMY OF INGUINAL HERNIA. 
 
 The anatomy of the inguinal region may now be examined 
 with reference" to hernia. Most of the parts contained in it 
 have already been noticed, without, however, any particular 
 regard to their relations to protrusion of the bowel. They 
 will now be described as they appear in the process of dis- 
 section. 
 
 The INGUINAL KEGION is the triangular space bounded 
 above by a line extending from the anterior superior spinous 
 process of the ilium to the linea alba, below by Poupart's 
 ligament and the upper border of the body of the pubic 
 bone, and internally by the linea alba. 
 
 Dissect the skin from the superficial fascia, and reflect 
 it downwards. This dissection should be carried to a short 
 distance below Poupart's ligament and down to the dorsum 
 of the penis. The superficial fascia contains the arteria ad 
 cutem abdominis, and one or two small branches from the 
 superior external pudic ; also three or four lymphatic glands, 
 which are usually imbedded in it along Poupart's ligament. 
 Near the linea alba, the fibres which descend in the fascia to 
 form the suspensory ligament of the penis, Fig. 148 (2), should 
 be observed. The adipose layer is placed next to the skin, 
 Fig. 148 (i, i), and presents an uneven areolar appearance. 
 There is generally considerable fat in this region, espe- 
 cially towards the pubis. The membranous layer lies next 
 to the tendon of the external oblique. Its under surface has 
 30 
 
350 OF THE ABDOMEN. 
 
 a smooth even appearance. This layer, Fig. 148 (4, 4), alone 
 is sometimes spoken of as constituting the superficial fascia. 
 The fascia is next to be dissected and reflected down- 
 wards in the same manner, and to the same extent, as the 
 skin. To preserve the intercolumnar or spermatic fascia, 
 which is reflected from the margin of the external abdomi- 
 nal ring down over the spermatic cord, it is better to raise 
 the superficial fascia from the ring and cord by insinuating 
 the handle of the scalpel or the finger under it, and sepa- 
 rating it from the parts beneath. Poupart's ligament, from 
 its origin to its insertion into the spine of the pubis, should 
 be carefully cleaned, so as to be brought distinctly into view, 
 and the cord should be raised for a short distance below the 
 ring, so that it may be made more or less tense, and thus 
 show more clearly how the intercolumnar fascia is connected 
 to the ring. 
 
 To raise the tendon of the external oblique, make an in- 
 cision from the anterior superior spinous process of the ilium 
 transversely to within about an inch and a half of the linea 
 alba, and another from this to the pubis on the inner side of 
 the ring ; then dissect it from the internal oblique and the 
 cord. The first incision should not be carried beyond the 
 junction of the two oblique muscles, as it is only the tendon 
 of the external oblique that is to be turned down. If the 
 handle of the scalpel be carried along the cord through the 
 ring, the intercolumnar fascia will be seen coming from the 
 edges of the ring to surround the cord. Fibres will also be 
 observed extending transversely over the cord as it passes 
 through the ring, and for a short distance below it; these 
 are sometimes called the intercolumnar bands or fibres. Fig. 
 146 (is). Detach the intercolumnar fascia from the margin 
 of the ring, and observe the manner in which it is formed. 
 
 The EXTERNAL RING, Fig. 148 (is), consists of a slit in the 
 tendon of the external oblique, commencing from an inch to 
 two inches above, and external to the pubis ; the fibres di- 
 verge as they pass downwards and inwards to be inserted, 
 the lower external into the spine of the pubis with Pou- 
 part's ligament, and the upper internal into the symphysis 
 and the pubic bone on the opposite side. The term co- 
 lumns or pillars, Fig. 148 (i 4, i s), has been applied to these 
 fibres. The fibres of the internal column cross those of the 
 
ANATOMY OF INGUINAL HERNIA. 
 
 351 
 
 corresponding one on the opposite side. The opening thus 
 formed is of a triangular shape, with the base towards the 
 
 A VIEW OP THE EXTERNAL PARTS CONCERNED ix INGUINAL AND FEMORAL 
 HERNIA. 1, 1. The common integument and adipose tissue of the abdomen turned 
 back. 2. The penis, with its suspensory ligament deprived of the integument. 3. 
 Integunrent of the scrotum drawn down. 4,4. Fascia superficial of the abdomen. 
 5. The same on the thigh. 6. The left spermatic cord covered by the fascia super- 
 ficialis. 7. The inguinal glands which are imbedded in the fascia superficialis. 
 8. Branch of the external pudic artery. 9. Fascia superficialis turned off the thigh. 
 10. Tendon of the external oblique. 11. Linea alba. 12. External oblique muscle. 
 13. External abdominal ring. 14. Its superior column. 15. Its inferior column. 
 16. Testicle covered by the cremaster muscle. 17. Anterior superior spinous pro- 
 cess of ilium. 18. Close attachment of the fascia superficialis on the outside of 
 the thigh. 19. Cribriform openings in the fascia lata femoris. 20. Saphenous 
 opening. 21. Branch of the saphenous vein. 22. Saphenous vein. 23. External 
 femoral ring. 24. Testicle. 
 
 pubis. Its size varies very much in different subjects. In 
 the female it is usually much smaller than in the male. The 
 intercolumnar fibres, which arise generally from Poupart's 
 ligament, and extend upwards and inwards across the upper 
 part of the triangular opening, convert it into one of a 
 
352 OF THE ABDOMEN. 
 
 quadrangular shape, also diminish its size, and bind together 
 its columns. There are other fibres beneath these, which ex- 
 tend simply between the columns. 
 
 In cases of hernia, these fibres are stretched so as to allow 
 the columns to be separated further than is natural from 
 each other. If the hernia be one of long standing, they are 
 usually found considerably increased in size. 
 
 The boundaries of the ring, as will now be seen, are the 
 columns, one on each side, the body of the pubic bone be- 
 tween the insertion of the columns below, and the inter- 
 columnar fibres above. 
 
 Beneath the internal column is found a set of fibres 
 which arise from the linea pectinea, anterior to the insertion 
 of the conjoined tendon of the internal oblique and trans- 
 versalis, and pass upwards and inwards to be inserted into 
 the linea alba. They form the triangular ligament. Turn 
 down the tendon of the external oblique, and make it more 
 or less tense with hooks, then carefully remove the areolar 
 tissue from the internal oblique and cremaster muscles. The 
 lower fibres of the internal oblique are frequently somewhat 
 irregular in their position and direction, but a little care will 
 suffice to trace them distinctly and loosen them up from the 
 cord or separate them from the cremaster. The cord is next 
 to be separated from its connections in the inguinal canal, 
 and raised up with the tenaculum. The most difficult part 
 of this dissection is to preserve the fascia transversalis in the 
 posterior wall of the canal, and especially where it is re- 
 flected from the internal ring over the cord. The position 
 of the cord and the walls of the canal should now be care- 
 fully examined. 
 
 The INGUINAL CANAL, Fig. 150 (3, s), is about an inch 
 and a half in length. It extends from the internal to the 
 external ring. Its direction is oblique, from above down- 
 wards, from without inwards, and from behind forwards. 
 Its boundaries are, in front, the tendon of the external oblique, 
 with a portion of the internal oblique ; below, by Pouparfs 
 ligament ; behind, by the fascia transversalis externally, and 
 the conjoined tendon of the internal oblique and transversalis 
 internally; above, its boundary is more indefinite; it corre- 
 sponds to the space between the tendon of the external ob- 
 lique and the fascia transversalis, which includes the lower 
 borders of the internal oblique and transversalis muscles. 
 
ANATOMY OF INGUINAL HERNIA. 
 
 353 
 
 The internal oblique and transversalis muscles should now 
 be detached from Poupart's ligament, and reflected upwards 
 
 A VIEW OP THE DEEP-SEATED PARTS CONCERNED IN INGUINAL AND FEMORAL 
 HERNIA. 1, 1. Integument and adipose tissue. 2. Integument of the scrotum. 
 3. Fascia superficial abdominis and fascia lata femoris turned off. 4. External 
 oblique muscle. 5. Its tendon. 6. Linea alba. 7. Lower part of the external ob- 
 lique tendon divided and turned back. 8. Right testicle in the tunica vaginalis 
 testis. 9. Internal oblique and transversalis muscles. 10. Epigastric artery and 
 vein, as placed between the fascia transversalis and the peritoneum. 11. Points to 
 the surface of the peritoneum through the internal ring. 12. Cord covered by the 
 cremaster muscle lying in the inguinal canal. 13. External ring laid open. 14, 
 15. Infundibuliform fascia of the vessels laid open so as to expose them. 16. Pec- 
 tineus muscle. 17. The vessels in their sheath. 18. Penis and ligamentum sus- 
 pensorium. 19, 19. Testicle and cord in its entire length., 
 
 from the fascia transversalis. By making these muscles 
 tense, a good idea may be obtained of the extent and manner 
 in which they enter into the formation of the posterior wall 
 of the inguinal canal. As the tendon of the transversalis 
 curves downwards, it expands, so as to be inserted into the" 
 linea pectinea, and for some distance into Poupart's liga- 
 
 30* 
 
354 
 
 OF THE ABDOMEN. 
 
 ment ; thus it occupies a large portion of the space on the 
 inner side of the internal ring. 
 
 The FASCIA TRANSVERSALIS, Fig. 150 (i i, 12, and 25, se), 
 is thicker and more dense in the inguinal region than in 
 any other part of it. It adheres to Poupart's ligament 
 throughout its whole extent; but in front of the femoral 
 vessels the fascia is continued an inch or more into the thigh, 
 as will be seen in the dissection of the anatomy of crural 
 hernia, and in front of the iliacus internus and psoas magnus 
 muscles joins the iliac fascia. Internally it lies beneath the 
 conjoined tendon and the rectus, being closely connected to 
 the tendon of the trans versalis. 
 
 The INTERNAL KING, Fig. 150 (i e), is situated about half 
 
 Fig. 150. 
 
 A VIEW OP THE ABDOMINAL MUSCLES AND THE ABDOMINAL, OR INGUINAL CANAL. 
 1. External oblique muscle of the abdomen. 2. Its aponeurosis. 3. Its tendon 
 slit up and turned back to show the canal. 4, 4. Anterior superior spinous processes. 
 5. Upper portion of Poupart's ligament. 6. External column of the external ring. 
 7. Internal column of the external ring. 8. Intercrossing of thejtendons of the 
 two sides. 9, 9. Bodies of the pubes. 10. Upper boundary of the external ring 
 the line points to the ring. 11, 12. Fascia transversalis. 13. Fibres of the in- 
 ternal oblique turned up. 14. Fibres of the transversalis muscle. 15. Points to 
 the internal ring the opening is enlarged for the demonstration. 16. Sartorius. 
 17. Fascia lata femoris. 18. Rectus femoris. 19. Adductor longus. 20. Penis. 21. 
 Fascia lata of the right thigh. 22. Point where the saphenous vein enters the 
 femoral. 23. Fascia lata as applied to the vessels. 24. Insertion of the transver- 
 salis muscle on the pubis. 25, 26. Correspond to 11, 12, of the opposite side, and 
 indicate the fascia transversalis. 27. Poupart's ligament, turned off from the in- 
 ternal muscles. 28. Transversalis abdominis. 29. Internal oblique. 30. Rectus 
 abdominis. 
 
ANATOMY OF INGUINAL HERNIA. 355 
 
 way between the anterior superior spinous process of the 
 ilium and the symphysis pubis, and half an inch above Pou- 
 part's ligament. It is overlapped by the internal oblique, and 
 hence cannot be observed until this muscle is raised. To 
 examine this opening, cut through the fascia transversalis a 
 short distance above it, and separate the fascia from the 
 peritoneum down to where the cord enters the ring, then by 
 carrying the handle of the scalpel along the cord, the con- 
 tinuation of the fascia over it, and through the canal, is ren- 
 dered distinct ; showing that, while there is no opening through 
 the fascia from without, there is one from within through 
 which the bowel can escape from the cavity of the abdomen. 
 The internal ring then is an opening which leads into a 
 pouch formed by the testicle carrying before it the fascia 
 transversalis in its descent into the scrotum. Sometimes the 
 internal ring presents a well defined margin on one side, or 
 entirely around it. At other times, it is difficult to demon- 
 strate, satisfactorily, the reflection of the transversalis fascia 
 over the cord. When the cord is made tense, the 'fascia trans- 
 versalis, as it is reflected from the internal ring, presents a 
 funnel-shaped appearance, and hence the name of infundi- 
 buliform fascia has been given to this part of it. 
 
 The EPIGASTRIC ARTERY, Fig. 149 (i o), and Fig. 151 (i 3), 
 with its accompanying veins, will be found by dividing the 
 transversalis fascia on the inner side of the internal ring. It 
 lies between the fascia and peritoneum, and crosses the canal 
 nearly at right angles. Its distance from the internal ring 
 varies from one-fourth to one-half of an inch. 
 
 When the internal surface of the inguinal portion of the 
 parietes of the abdomen is examined, two pouches or fossae are 
 cJerved corresponding to the two rings. These are formed 
 l^Hihe remains of the hypogastric artery, which, in its course 
 from the internal iliac to the umbilicus, projects here into the 
 cavity of the abdomen. The peritoneum is reflected over it. 
 Sometimes the hypogastric artery is situated a short distance 
 to the inner side of the epigastric, when an additional small 
 pouch is formed. These fossae cause a greater or less predis- 
 position to rupture, according to their depth, by directing the 
 bowel against either the internal or external ring. 
 
 The student should now review the parts, the dissection of 
 which he has just completed, with reference to hernia. There 
 
356 OF THE ABDOMEN. 
 
 are two forms of inguinal hernia direct, or ventro-inguinal, 
 and indirect, or oblique. In the oblique form, the bowel 
 traverses the entire length of the canal passing through both 
 rings ; in the direct, it escapes directly through the external 
 ring, and does not pass through the canal. 
 
 In OBLIQUE HERNIA, the course of the bowel and the dif- 
 ferent coverings which it obtains in its descent, are as follows : 
 Its course is similar to that of the spermatic cord. As the 
 internal oblique overlaps the internal ring, it offers resistance 
 to the entrance of the bowel into the canal, hence the bowel 
 is forced downwards beneath the lower border of the muscle; 
 in the canal, it is directed downwards, inwards, and somewhat 
 forwards ; when it leaves the external ring, its direction is 
 towards the scrotum, along the course of the cord. The 
 coverings which it gets are, first, the peritoneum at the inter- 
 nal ring; this constitutes the sac; second, the transversalis, 
 or infundibuliform fascia, as it enters the canal; third, the 
 cremaster muscle, while passing through the canal ; fourth, the 
 inter columnar, or spermatic fascia, as it goes through the ex- 
 ternal ring ; fifth and sixth, the superficial fascia, and the in- 
 tegument j the last two coverings it receives entirely outside 
 of the canal. 
 
 The cremaster is usually found in front, and on the outside 
 of the tumor ; while the cord is generally situated behind, 
 and on the inner side. The bowel almost necessarily gets 
 between the cord and the cremaster, from their relative posi- 
 tion in the upper part of the canal. 
 
 In DIRECT HERNIA, the coverings are the same as in indi- 
 rect, with a single exception ; the conjoined tendon of the in- 
 ternal oblique and transversalis takes the place of the Oje- 
 master muscle. Sometimes the conjoined tendon is tonf^* 
 its fibres are separated so as to allow the bowel. to pass through 
 it ; when this happens, it will not constitute one of the cover- 
 ings. 
 
 Another form of direct hernia is sometimes described, in which 
 the bowel enters the canal between the epigastric artery and 
 the outer border of the conjoined tendon. 
 
 When the bowel passes through the internal ring, but is 
 retained in the canal, it is called bubonocele, or concealed in- 
 guinal hernia. In this case, the tendon of the external oblique 
 will form one of the coverings. 
 
VESSELS OF ABDOMINAL PARIETES. 357 
 
 The epigastric artery is the principal one to be avoided in 
 dividing a stricture in either form of inguinal hernia. This 
 is to be done by cutting upwards and parallel to the artery. 
 
 The seat of stricture in indirect hernia may be at the internal 
 ring, or where the cord passes under the internal oblique 
 muscle, or at the external ring. It occurs most frequently 
 at the internal ring, and, next to this, where the cord passes 
 beneath the muscle. In direct^hernia, the stricture may occur 
 at the external ring, or at the conjoined tendon, especially if 
 the tendon be perforated by the bowel. 
 
 There are other forms of inguinal hernia, as scrotal, con- 
 genital, and encysted. 
 
 Scrotal, is when the bowel' has descended into the scrotum. 
 The tumor in this form of hernia may acquire an enormous 
 size. 
 
 Congenital, is that form in which the bowel descends in the 
 tunica vaginalis, while it yet communicates with the cavity 
 of the peritoneum. 
 
 Encysted, is when the bowel descends behind the tunica 
 vaginalis, carrying with it a pouch of the peritoneum. 
 
 The/asc^a transversalis has been observed as forming an 
 important part of the anatomy of inguinal hernia. It lines 
 the internal surface of the transversalis muscle in other por- 
 tions of the abdominal parietes, where it consists of but little 
 more than a thin, delicate layer of areolar tissue, and requires 
 no particular notice. 
 
 / 
 
 The arteries, which supply the parietes of the abdomen 
 anteriorly and laterally, are the internal mammary, the lower 
 intercostal^fhe lumbar, the internal circumflex ilii, the arteria 
 ajj.putem abdominis, and the epigastric. 
 
 INTERNAL MAMMARY enters the abdomen beneath the 
 cartilage of the seventh rib, descends a short distance behind 
 the rectus, and then perforates its sheath. While in the 
 sheath, it gives branches to the muscle, and sends off branches 
 which go to supply the integuments and the broad muscles. 
 They inosculate freely with branches of the epigastric. 
 
 The INTERCOSTAL leave the intercostal spaces, and pass 
 between the internal oblique and transversalis muscles. They 
 inosculate with the internal mammary, epigastric, and lumbar 
 arteries. 
 
358 OF THE ABDOMEN. 
 
 The LUMBAK divide into the posterior and anterior or ab- 
 dominal branches. The latter pass between the middle layer 
 of the fascia Inmborum and the quadratus lumborum muscle, 
 and thence between the internal oblique and transversalis 
 muscles. They anastomose above with the intercostal, in the 
 middle with the internal mammary, and below, with the ilio- 
 lumbar and internal circumflex ilii arteries. 
 
 The INTERNAL CIRCUMFLEX ILII, Fig. 151 (14), arises from 
 the external iliac just behind, or a little above Poupart's liga- 
 ment. It passes upwards and outwards to the anterior supe- 
 rior spinous process of the ilium, where it divides into two 
 branches. One of these ascends between the internal oblique 
 and transversalis, to terminate in the muscles and integument, 
 and to inosculate with the intercostal and internal mammary ; 
 the other runs along the crest of the ilium, and anastomoses 
 with the lower lumbar. The arteria ad cutem abdominis has 
 been noticed in connection with the fascia superficialis. 
 
 The EPIGASTRIC, Fig. 151 (is), arises from the external 
 iliac, just above Poupart's ligament, passes inwards and up- 
 wards behind the inguinal canal, and between the fascia trans- 
 versalis and peritoneum. It gets behind the rectus, enters 
 its sheath, and passes up to the umbilicus, where, or a little 
 above, it divides into branches to supply the muscle, and to 
 anastomose with the internal mammary. It sometimes gives 
 off the obturator and the internal circumflex ilii. Its usual 
 branches are, a pubic, which goes behind the pubis ; a cremas- 
 teric, which enters the inguinal canal, and accompanies the 
 spermatic cord to the testicle ; a branch^ to anastomose with 
 the obturator when it arises from the internal iliac ; some- 
 times this branch is quite large, and passes near the femoral 
 ring. The origin of the epigastric is subject to some varia- 
 tion. It may arise from the femoral or from the external 
 iliac, some distance above Poupart's ligament. 
 
 The nerves which supply the abdominal parietes are the 
 inferior intercostal and the anterior branches of the lumbar. 
 
 The INTERCOSTAL NERVES, when they leave the intercostal 
 spaces, pass forwards between the internal oblique and trans- 
 vepsalis muscles as far as the rectus, the sheath of which they 
 perforate. Besides muscular branches, they give off two 
 sets of cutaneous branches, the anterior and the lateral. The 
 former leave the sheath of the rectus, and supply the integu- 
 
NERVES OF ABDOMINAL PARIETES. 
 
 359 
 
 ment on the front part of the abdomen ; the latter are given 
 off about midway between the spine and the linea alba, pass 
 
 Fig. 151. 
 
 5 1 3 f7 I? 8 9 
 
 A VIEW OF THE ARTERIES IN THE GROIN OF THE LEFT SIDE IN THEIR RELATIVE 
 POSITIONS, THE INGUINAL CANAL BEING OPENED. I. Aponeurosis of the obliquus 
 externus muscle. 2. Section of this muscle. 3. Its tendon turned off and upwards. 
 4. Its tendon turned downwards and exposing the inguinal canal. 5, 6, 7. Subcu- 
 taneous .arteries. 8. A branch of the arteria ad eutem abdominis. 9. Surface of the 
 Obliquus internus muscle. 10. Surface of the transversalis muscle. 11. Section of 
 the fascia transversalig. 12. Branch of the epigastrie artery. 13. Epigastric artery. 
 14. Internal circumflex ilii. 15. Lower edge of the transversalis muscle, giving off 
 fibres to form the cremaster. 16. Section of the linea alba. 17. Kectus abdominis 
 muscle. 18. Spermatic cord, entire. 19. An arteriole from the epigastric. 20. 
 Another to" the fascia. 21. End of the external iliac artery. 22. The femoral 
 artery. 23. The profuncla femoris. 24. External circumflex. 25. A branch to tbe 
 fascia lata. 26. External pudic artery. 
 
 through the internal and external oblique muscles to the 
 skin. When these branches enter the superficial fascia, they 
 divide into anterior and posterior filaments, to anastomose 
 with each other, and also with the posterior spinal nerves. 
 
 The last dorsal nerve is relatively very large. Its lateral 
 cutaneous branch, after perforating the internal and external 
 oblique muscles, descends to the crest of the ilium, where it 
 
360 OF THE ABDOMEN. 
 
 divides into cutaneous branches, which are distributed to the 
 integument in the gluteal region. 
 
 The branches from the lumbar plexus are the superior and 
 middle musculo-cutaneous. 
 
 The SUPERIOR MUSCULO-CUTANEOUS, or ILIO-SCROTAL, 
 Fig. 178 (s), arises from the upper part of the plexus, per- 
 forates the psoas magnus, and runs over the quadratus lum- 
 borum muscle to the crest of the ilium, where it gets between 
 the transversalis and internal oblique muscles. It divides 
 above the crest into an abdominal and pubic or an external 
 and an internal branch. The abdominal branch has a course 
 similar to the intercostal nerves. The pubic division passes 
 above Poupart's ligament, and joins the spermatic cord in the 
 inguinal canal, passes through the external ring, and is dis- 
 tributed to the integument in the pubic region. Sometimes 
 it gives off a cutaneous branch, which passes over the crest 
 of the ilium, and is lost in the gluteal region. 
 
 The MIDDLE MUSCULO-CUTANEOUS, Fig. 178 (s), has 
 nearly the same origin and course as the preceding. It 
 generally anastomoses with the superior musculo-cutaneous 
 at the upper portion of Poupart's ligament. 
 
 It will be observed that the course of the abdominal nerves 
 is, for the most part, the same, while that of the arteries is 
 quite different. The parietes of the abdomen are abundantly 
 supplied with both nerves and vessels. 
 
 SECT. II. DISSECTION OF THE CAVITY OF THE ABDOMEN. 
 
 To open the cavity of the abdomen, make an incision from 
 the xiphoid cartilage to the umbilicus and a little to one side 
 of the linea alba, and another on each side from the umbilicus 
 to the anterior superior spinous process of the ilium. 
 
 This cavity is divided into nine regions, Fig. 152, to which 
 two i others are sometimes superadded. Although these 
 divisions are arbitrary, they are still useful for the purpose 
 of locating the different organs in the abdomen. They are 
 found by making two transverse and two vertical lines. The 
 transverse lines extend, the superior from the cartilage of 
 the eighth rib on one side to the corresponding rib on the 
 opposite side, and the inferior from one anterior superior 
 
DISSECTION OF CAVITY OF THE ABDOMEN. 361 
 
 spinous process of the ilium to the other. The vertical lines 
 are drawn, one on each side, from the cartilage of the eighth 
 rib to the centre of Poupart's ligament. Thus six lateral and 
 
 Fig. 152. 
 
 SURFACE OF THE ABDOMEN, WITH LINES (1, 2, 3, 4) DRAWN UPON IT, MARKING OFF 
 ITS ARTIFICIAL SUBDIVISIONS INTO REGIONS. 5, 5. Right and left hypochondriac. 
 6. Epigastric. 7. Umbilical. 8, 8. The two lumbar. 9. Hypogastric. 10, 10. 
 The right and left iliac. 11. Pubic. 
 
 three middle regions are formed. The lateral, commencing 
 above, are the right and left hypochondriac, the right and left 
 lumbar, and the right and left iliac ; the middle are the epi- 
 gastric, the umbilical, and the hypogastric. 
 
 The other two are named, the cardiac, and the pubic. The 
 former comprises a small space, without any definite bound- 
 aries, around the ensiform cartilage; the latter is situated 
 just above the pubic bones. 
 31 
 
362 OF THE ABDOMEN. 
 
 The manner in which these regions are occupied, will be 
 better understood after the viscera have been described. "We 
 shall give here merely a general account of the location of 
 the different organs, preparatory to the examination of the 
 peritoneum, and in order that the student may obtain some 
 idea of the position of the different viscera in the abdomen 
 before he proceeds to the study of them separately. He can- 
 not become too familiar with the exact situation and relation 
 of each viscus in this cavity. 
 
 In the upper part of the cavity, Fig. 153, and in relation 
 with the diaphragm, are the liver, the stomach, and the spleen. 
 The liver alone occupies the left hypochondriac region; a 
 part of the liver and stomach are situated in the epigastric 
 region ; the spleen and a portion of each of the other organs 
 are found in the left hypochondriac region. The pancreas is 
 situated behind the stomach, extending from the spleen on 
 the left to the concavity of the duodenum on the right. The 
 kidneys are placed in the back part of the lumbar regions. 
 The ccecum is in the right iliac region. The colon commences 
 at the ca3cum, passes upwards through the right lumbar 
 region to the liver, then turns to the left and goes across 
 the upper part of the umbilical, below the liver and stomach, 
 to the left lumbar region, where it is in contact with the 
 spleen; thence it descends, in front of the kidney, to the 
 left iliac region, where, after forming the sigmoid flexure, 
 it enters the pelvis and terminates in the rectum. The 
 duodenum begins at the' right extremity of the stomach, 
 proceeds about two inches and a half to the right between the 
 liver and colon, turns downwards behind the colon, and then 
 passes to the left through the mesentery, to terminate in the 
 jejunum. The remainder of the small intestine, consisting of 
 the jejunum and ileum, is found principally in the umbilical 
 region, and terminates in the caecum. 
 
 The PERITONEUM is the largest serous sac in the body. It 
 presents two surfaces, an external and an internal; the latter 
 is smooth and polished, being constantly lubricated with a 
 serous exhalation ; the former, or external, is everywhere ad- 
 herent. It is divided into a visceral and a parietal portion ; 
 and different parts of these, as will be seen, are designated by 
 different names. 
 
 Above the umbilicus, and in the median line, the parietal 
 
DISSECTION OF CAVITY OF THE ABDOMEN. 363 
 
 portion is reflected upon the remains of the umbilical vein 
 of the foetus, and forms the suspensory ligament of the liver. 
 Below the umbilicus it presents three folds which correspond, 
 in the middle, to the urachus, and on the sides to the umbili- 
 cal arteries of the foetus. In some parts it adheres closely to 
 the abdominal parietes, while in others, as in the lumbar and 
 iliac regions, more or less loose areolar tissue intervenes. 
 
 The visceral portion is rendered somewhat complex by its 
 numerous reflections. To understand it properly, the student 
 cannot rely upon a mere description of it ; he must examine 
 it for himself. The best mode of doing this is to study it in 
 its connections with the organs which it invests, and from 
 which it is reflected to the parietes. It is in this way that 
 we shall describe it. 
 
 If the liver be examined, it will be found that the perito- 
 neum covers nearly the whole of its exterior surface, includ- 
 ing a portion of the gall-bladder ; and that it is reflected from 
 it at four different places. From its upper and anterior 
 surface in the median line it is reflected to the diaphragm, 
 so as to form a fold which extends from the ligamentum teres 
 or the remains of the umbilical vein of the foetus, which it 
 includes, to the posterior border jrf the liver. This fold is 
 called the suspensory ligament, and indicates the dividing line 
 between the right and left lobes of the liver. At the poste- 
 rior border it is reflected to the diaphragm, and forms first 
 the coronary and then the right and left lateral ligaments; of 
 the last two the right one is short, and attaches the right 
 lobe closely to the diaphragm, while the left is longer, and 
 allows the left lobe a considerable degree of mobility inde- 
 pendently of the diaphragm. From the under surface it 
 is reflected in three laminae. The anterior two form a fold 
 which contains, in its right border, the hepatic artery and duct, 
 the portal vein, the hepatic plexus of nerves, and the deep-seated 
 lymphatics of the liver, and below, the stomach. This fold 
 between the liver and the stomach, is named the gastro-hepatic 
 omentum, Fig. 154 (9). These two laminae leave the con- 
 vex border of the stomach, pass down in front of the trans- 
 verse colon, without adhering to it, and descend to the lower 
 part of the abdomen, Fig. 153 (27, 27), where they are re- 
 flected on themselves ; they then pass upwards to the trans- 
 verse colon, to inclose which they separate, and then reunite and 
 go backwards to the spine, forming the transverse meso-colon ; 
 
364 OF THE ABDOMEN. 
 
 having reached the spine, they again separate, the one to de- 
 scend, to invest the small intestines, and form the mesentery, 
 the other to ascend over the lower portion of the duodenum, 
 and the pancreas to the under surface of the liver. 
 
 Thus it will be seen that the posterior lamina of the gastro- 
 hepatic or lesser omentum passes down behind the stomach 
 to near the lower part of the abdomen, and returns again to 
 the liver, passing over the transverse colon, a part of the duo- 
 denum, and the pancreas. It is this lamina which forms the 
 lesser peritoneal sac. Although applied to the anterior lamina 
 from the liver to the spine, except where they separate to 
 inclose the stomach and colon, they are nowhere continuous, 
 except at the right border of the gastro-hepatic omentum. 
 If the student will examine this border, he will find that the 
 two laminas of the gastro-hepatic omentum are here con- 
 tinuous around the hepatic vessels, and that behind it is 
 an opening which leads into the lesser sac or pouch formed 
 by the posterior lamina. This opening is called the foramen 
 of Winskw, Fig. 154 (9). 
 
 It is through this foramen only that the posterior surface of 
 the stomach, the anterior surface of the transverse colon and 
 the pancreas, and the lobus Spigelii can be reached with- 
 out destroying the continuity of the peritoneum. It has, in 
 front, the hepatic vessels, behind, the ascending vena cava, 
 above, the lobus Spigelii, and below, the superior transverse 
 portion of the duodenum. 
 
 The omentum majus, or gastro-colic omentum,, Fig. 153 (27, 
 37), consists of the two Iamina3 which have already been de- 
 scribed as passing down from the convex border of the 
 stomach in front of the small intestine, and again ascending 
 to the transverse colon. It has been compared to an empty 
 sac within a sac, and although thin and transparent, it consists 
 of two anterior and two posterior laminae. In the lower part 
 of it the laminad adhere so closely to each other that it is 
 difficult to separate them, and not unfrequently it presents a 
 cribriform or net-like appearance. It usually descends lower 
 on the left than on the right side. Between its lamime are 
 found vessels, and more or less adipose substance. Its most 
 probable use is to facilitate the movements of the convolu- 
 tions of the small intestine on themselves and on the ab- 
 dominal parietes. In some cases, it extends but a very little 
 distance below the colon. 
 
DISSECTION OF CAVITY OF THE ABDOMEN. 365 
 
 The whole of the spleen, except the hilum, or fissure, 
 through which the vessels enter it, is invested by the peri- 
 toneum. It is reflected from the spleen along the splenic 
 vessels to the left extremity of the stomach, where it becomes 
 continuous with the lamina which passes over the anterior 
 surface of that organ. This portion of it is designated the 
 gastro-splenic omentum. 
 
 Below the spleen, the peritoneum is continued down over 
 the left extremity of the transverse colon and the descending 
 colon, forming the descending meso-colon. From the meso- 
 colon it is reflected on the left to the parietes, and on the right 
 it is continuous with the anterior lamina of the omentum 
 majus and the mesentery ; lower down it is reflected over the 
 ' spine, the aorta, the vena cava, the ureter and iliac vessels. It 
 lies in front of the left kidney, from which it is usually sepa- 
 rated by fat, areolar tissue, and partly by the colon. 
 
 From the posterior border of the right lobe of the liver 
 it is reflected downwards over the right kidney, the superior 
 transverse portion of the duodenum, the right extremity of the 
 transverse colon, the commencement of the inferior transverse 
 portion of the duodenum, the ascending colon and ccecum, form- 
 ing the ascending meso-colon and the meso-ccecum. On the left, 
 it joins the anterior lamina of tfte~ omentum majus and the 
 mesentery ; on the right, it joins the parietal portion. The 
 caecum is sometimes almost wholly covered by peritoneum. 
 
 The laminae of the ascending and of the descending meso- 
 colon, above the sigmoid flexure, are separated some dis- 
 tance apart, so as to leave the posterior aspects of these 
 portions of the colon uncovered by peritoneum. Thus it 
 is that the large intestine can be punctured without wound- 
 ing the peritoneum. The laminae of the transverse meso- 
 colon and of the sigmoid flexure in the left iliac region 
 are applied to each other so as to leave just space enough 
 for the vessels and nerves to reach the parietes of the in- 
 testine. 
 
 The difference in the length of the meso-cola should be 
 observed. That of the transverse colon as well as that of 
 the sigmoid flexure are usually several inches in length, al- 
 lowing a considerable degree of mobility to those parts of 
 the large ;ntestineT 
 
 In the pelvis, the peritoneum is reflected over the upper 
 
36ft OF THE ABDOMEN. 
 
 part of the rectum to the parietes forming the meso-rectum 
 it also covers the upper and posterior part of the bladder, from 
 which it is reflected behind to the rectum, and laterally and 
 anteriorly to the parietes, forming the posterior lateral liga- 
 ments of that organ. 
 
 In the female it covers the anterior upper two-thirds of the 
 uterus, and the whole of it, posteriorly, including the upper 
 and: posterior part of the vagina. As it is reflected from the 
 uterus it forms several folds, as the broad ligaments laterally, 
 the recto-uterine behind, and the vesico-uterine in front. 
 
 EELATIONS OF THE ABDOMINAL VISCERA. 
 
 Before describing the special anatomy of the abdominal 
 viscera, we shall give a brief description of their relations 
 to each other and to the surrounding parts. It is only in 
 the dissecting-room that the student will be able to acquire 
 this knowledge in a manner that will make it satisfactory 
 and useful to himself. The study of the special anatomy of 
 most of the organs will require their removal from the ab- 
 dominal cavity, which must necessarily destroy their relations 
 to contiguous parts. 
 
 In the upper part of the abdomen, Fig. 153, there are 
 three organs, whose relations to the diaphragm, and through 
 it to the lungs and heart in the thorax, should be carefully 
 observed. These are the liver, the stomach, and the spleen. 
 Of these only the liver has any direct relation to the right 
 lung. It is received deeply into the concavity of the lung, 
 ascending in expiration as high as the fifth, or even the 
 fourth intercostal space. It necessarily rises and descends 
 alternately in expiration and inspiration. 
 
 Both the liver and the stomach are placed in apposition 
 with the central part of the diaphragm, and are separated 
 from the heart only by the cordiform tendon and the ad- 
 herent portion of the pericardium. 
 
 The spleen, the stomach, and a small portion of the left lobe 
 of the liver occupy the concavity of the left part of the dia- 
 phragm, and consequently are in relation with the left lung. 
 They do not ascend quite so high as the liver does on the 
 right side. 
 
 It will be seen from the position of the liver that if it 
 
RELATIONS OF THE ABDOMINAL VISCERA. 367 
 
 should become agglutinated to the diaphragm, a hepatic 
 abscess might open into the pleural cavity above, or if adhe- 
 
 Fig. 153. 
 
 A VIEW OP THE VISCERA OP THE CHEST ANP ABDOMEN, IN THEIR NATURAL 
 POSITION, AS GIVEN BY THE REMOVAL OF THE ANTERIOR PARIETES or EACH CA- 
 VITY. 1, 2. The ribs forming the side of the chest 3. Fatty tissue in the ante- 
 rior mediastinum. 4, 4. The section of the pleura of each side. 5. The pericar- 
 dium inclosing the heart. 6. Superior lobe of the right lung. 7. Inferior lobe of 
 the right lung. 8. The fissure which separates them. 9. Upper lobe of the left 
 lung. 10. Lower lobe of the le*'t lung. 11. Fissure between them. 12. A trans- 
 verse section of the diaphragm. 13. Superior face of the right lobe of the liver. 
 14. Superior face of the left lobe of the liver. 15. Lower end of the gall-bladder. 
 16. Inferior and anterior edge of the liver. 17. Round ligament of the liver. 18. 
 Suspensory ligament of the liver. 19. Anterior face of the stomach. 20. Its 
 greater, extremity. 21. Its lesser extremity. 22. Its lesser curvature. 23. Its 
 greater curvatwre. 24. The pylorus. 25. The duodenum. 26. A part of the gas- 
 tro-hepatic omentum. 27,27. The majus omentum. 28,28. Convolutions of the 
 small intestines, seen through this omentum. 29. The spleen. 30, 30. The large 
 intestines. 31, 31. Parietes of the abdomen turned down. 
 
368 OF THE ABDOMEN. 
 
 sions between the diaphragm and the lung should exist at 
 the same time, the pus might find its way into the bronchial 
 tubes. An effusion into the cavity of the pleura would 
 press the liver downwards ; or, in case of enlargement of 
 the liver, the lung might be pressed upwards. 
 
 Abscesses of the liver may open externally through the 
 intercostal spaces, or lower down through the anterior parietes 
 of the abdomen. The reflections of the pleurse and of the pe- 
 ritoneum are such, that if an instrument should be carried 
 horizontally backwards through the sixth or seventh inter- 
 costal space, it would pass through the former eight times and 
 the latter four times. 
 
 It is mainly through the medium of the liver and stomach 
 that the impulse of the heart is transmitted to the abdomi- 
 nal parietes. The portions of these organs which correspond 
 to the cordiform tendon of the diaphragm are subjected to 
 scarcely any upward or downward movement. 
 
 The spleen is pressed on by the contraction of the dia- 
 phragm. This sometimes gives rise to pain in this organ 
 after running. If it be enlarged, the pain may be greatly in- 
 creased. It is in relation with the ninth, tenth, and eleventh 
 ribs, through the medium of the diaphragm, and may be 
 pressed on by them. The position of the spleen is deep in 
 the left hypochondriac region, and cannot be reached by 
 pressure upon the external surface of the body, except 
 through the lower ribs, or by pressing the hand upwards 
 underneath them. 
 
 The under surface of the liver is in relation with the right 
 kidney a the upper and right part of the colon, the superior 
 transverse portion of the duodenum, the stomach, and the 
 pancreas. Hence hepatic abscesses may open into the colon, 
 the duodenum, or the stomach. The gall-bladder rests on 
 the pylorus or duodenum and the colon, which are frequent- 
 ly stained with bile in the dead subject ; gall-stones some- 
 times escape by ulceration into the colon or duodenum. It 
 corresponds very nearly to the cartilage of the eighth or 
 ninth rib, and is about two inches and a half to the right of 
 the median line or linea alba. 
 
 The anterior surface of the stomach is in relation with the 
 left lobe of the liver, the diaphragm, and the anterior walls 
 of the abdomen. The posterior surface corresponds to the 
 pancreas, the splenic vessels, the solar plexus, and the aorta. 
 
RELATIONS OF THE ABDOMINAL VISCERA. 369 
 
 Its left extremity projects from two to three inches to the left 
 of the cardiac orifice, is in contact with the concavity of 
 the spleen, and is just above the left kidney and renal cap- 
 sule. Its cardiac orifice is situated below the diaphragm, and 
 
 Fig. 154. 
 
 A VIEW OF THE SAME VlSCERA, AFTER THE REMOVAL OF THE FAT IN THE 
 CHEST AND THE OMENTUM MAJUS OF THE ABDOMEN. THE LIVEU ALSO HAS BEEN 
 TURNED BACK TO SHOW ITS TJj&UER SURFACE AND THE LESSER OMENTUM. 1. The 
 great bloodvessels of the heart. 2. The lungs of each side. 3. The heart. 4. 
 The diaphragm. 5. Under surface of the liver. 6. The gall-bladder. 7. Union of 
 the cystic and hepatic ducts to form the ductus choledochus. 8. Anterior face of 
 the stomach. 9. The gastro-hepatic, or lesser omentum. A female catheter has 
 been pgssed through the foramen of Winslow, and is seen through the omentum. 
 10. Gastro-coliC, or greater omentum, cut off, so as to show the small intestines. 11. 
 The transverse colon, pushed slightly downwards. 12. Its ascending portion, also 
 pushed down. 13. Small intestines. 14. The sigmoid flexure. 15. Appendicula 
 vermifonnis. 
 
370 OF THE ABDOMEN. 
 
 behind the posterior border of the left lobe of the liver, near 
 the median line. The pyloric orifice is situated about three 
 or four inches lower down in the abdomen, and to the right 
 side. It corresponds nearly to the position of the gall- 
 bladder. It is much nearer to the anterior parietes than the 
 cardiac orifice, and hence tumors which have their seat near 
 the pyloric orifice can be more easily felt than when near 
 the cardiac. The junction of the stomach and duodenum is 
 indicated by a circular constriction. The superior or concave 
 border is occupied by the lesser omentum, and looks towards 
 the liver. The convex border is in relation with the meso- 
 colon behind, and is occupied with the commencement of the 
 gastro-colic omentum. The position of the stomach is altered 
 somewhat when it is distended. Its anterior surface then 
 looks upwards, and its posterior downwards ; its borders are 
 also changed, the convex one is directed forwards,, and the 
 concave backwards. 
 
 The student may now proceed to examine the connections 
 of the duodenum. This can be done more satisfactorily if 
 it, together with the stomach, be moderately inflated. For 
 this purpose, a pipe may be inserted into the upper part of 
 the jejunum. 
 
 The duodenum presents three parts for study; a superior 
 transverse, a descending, and an inferior transverse portion. The 
 first division commences at the pylorus, and extends about 
 two inches upwards, backwards, and to the right side, in 
 contact with the liver and gall-bladder. It is covered on 
 both sides by peritoneum, and consequently is quite mov- 
 able. The vena portas and the ductus choledochus communis 
 pass behind it. 
 
 The descending portion passes downwards about three inches, 
 having the transverse colon in front and the concave border 
 of the kidney and its vessels behind, the ascending colon on 
 the outer side, and the head of the pancreas on the inner side. 
 This portion is only partly covered by peritoneum. The 
 biliary and pancreatic ducts open into its inner and posterior 
 part near the middle. 
 
 The third division is situated between the laminaB of the 
 meso-colon. It passes from the right to the left across the 
 right crus of the diaphragm, the vena cava, and the aorta. 
 The pancreas is placed above, and partly separated from it 
 by the mesenteric vessels. It presents a slight bulging below 
 the transverse colon, and near its commencement. Its ter- 
 
KELATIONS OF THE ABDOMINAL VISCEEA. 371 
 
 mination in the jejunum is seen on the left side of the me- 
 sentery. Like the descending portion, it is only partly covered 
 by peritoneum. 
 
 The middle and lower portions of the duodenxim are so 
 fixed by their connections that they cannot well be displaced 
 unless by the development of a tumor. The first portion 
 may be drawn down more or less by the stomach. 
 
 The small intestine below the duodenum consists of the 
 jejunum and ileum. It is convex anteriorly and concave pos- 
 teriorly. It occupies the umbilical and hypogastric regions, 
 and extends laterally into the lumbar and iliac. It is at- 
 tached to the posterior wall of the abdomen by the mesentery, 
 which extends obliquely across the spine from the left lum- 
 bar region downwards to the right iliac. The mesentery is 
 short at its extremities, but much longer in the middle, where 
 it allows a great degree of mobility to the corresponding- 
 portion of the intestine. It contains between its laminae the 
 mesenteric vessels, nerves, and glands. The convolutions of 
 the jejunum and ileum have no regular form. They are in 
 contact with the anterior parietes of the abdomen, except 
 when the omentum majus covers .tkem, and are separated 
 from the viscera above by the transverse colon and its meso- 
 colon. They are usually found partly lodged in the pelvis, 
 where they are in contact with the rectum and bladder, and 
 in the female with the uterus. Their mobility is such that 
 they can adapt themselves to any changes that may take 
 place in the contiguous organs, or in the condition of the 
 abdominal cavity. 
 
 The large intestine consists of the ccecum, colon, and rectum. 
 
 The ccecum is situated in the right iliac region. It is 
 attached to the iliac fossa by the meso-caecum. It varies in 
 length from an inch and a half to three or four inches. It 
 rests on the iliac fascia, and has, in front and on the inner 
 side of it, the convolutions of the small intestine ; when dis- 
 tended, it is in contact with the anterior abdominal parietes. 
 The appendix vermiformis cceci is joined to it inferiorly. It 
 is a small, hollow, cylindrical body, from two to four inches 
 in length, and bound down by a fold of the peritoneum. The 
 small intestine joins the large at the junction of the caecum 
 and colon. * 
 
 The colon is divided into the ascending, the transverse, and 
 the descending portions ; the latter includes the sigmoid flexure. 
 
 The first division ascends through the right lumbar region 
 
372 OF THE ABDOMEN. 
 
 to the under surface of the liver. It lies at first on the an- 
 terior layer of the fascia lumborum, and then on the kidney ; 
 the vertical portion of the duodenum and the convolutions 
 of the small intestine are placed on the inner side, and the 
 latter also in front of it when it is empty. Externally, it is 
 applied to the wall of the abdomen. The lower part of it 
 can be reached through the lumbar region without impli- 
 cating the peritoneum. 
 
 The transverse colon, sometimes called the arch of the colon, 
 extends from the inferior surface of the right lobe of the liver 
 to the spleen in the left hypochondriac region, where it is 
 continuous with the descending colon. Its position is below 
 that of the liver, stomach, and spleen. As it crosses the 
 abdomen, it has to ascend to reach the spleen, as that organ 
 is so much smaller than the liver. It is separated from the 
 anterior abdominal parietes by the descending laminae of the 
 omentum majus. The small intestine is below, and the 
 meso-colon behind it. It frequently has attached to it 
 numerous small pouches of peritoneum, which contain fat. 
 These are called the appendices epiploicce. They are not 
 known to perform any function. The transverse colon is 
 allowed, from its position and attachments, a greater degree 
 of mobility than any other portion of the intestinal canal; 
 hence its direction and situation are subject to marked 
 changes. It is sometimes met with passing down into the 
 hypogastric region, and again ascending to the left hypochon- 
 driac. 
 
 The descending colon passes down through the left lumbar 
 to the left iliac region. Its relations are similar to those of 
 the ascending colon. It is somewhat longer, and is not as 
 much covered by the peritoneum, hence it can be perforated 
 with less danger of wounding the peritoneum ; its posterior 
 or non-peritoneal surface also corresponds to the fascia lum- 
 borum higher up above the crest of the ilium, on account of 
 the left kidney being situated higher than the right. 
 
 The sigmoid flexure is generally found partly in the left iliac 
 fossa and partly in the pelvis. It forms a double curve. From 
 the length of its meso-colon it has more mobility than any other 
 portion of the large intestine, except the transverse colon. 
 Its direction is downwards, and from left to right. It is sub- 
 ject to much variation in the length, direction, and position 
 of its flexures. When it is distended with gas or fecal matter, 
 
RELATIONS OF THE ABDOMINAL VISCERA. 373 
 
 it is in direct apposition with the walls of the abdomen, and 
 can be felt during life through the parietes; but when it is 
 empty, the convolutions of the small intestine usually inter- 
 vene. It terminates in the rectum opposite the left sacro- 
 iliac symphysis, without any precise line of demarcation. 
 
 Only the superior part of the rectum can be observed with- 
 out a dissection of the pelvis. Its relations to the bladder 
 and to the uterus, in the female, may be noticed at the present 
 time, leaving the study of it until the pelvic viscera are 
 examined. 
 
 The parts surrounded by the capsule of Glisson, in front 
 of the foramen of Winslow, should now be dissected. 
 
 They consist of the ductus choledochus communis on the right 
 side, the hepatic artery on the left, and the portal vein between 
 and behind the duct and artery. The hepatic plexus of nerves 
 accompanies the artery. From the ductus choledochus the 
 hepatic duct may be traced to the transverse fissure of the 
 liver, and the cystic duct towards the gall-bladder. The ductus 
 choledochus is about two inches and a half in length. Its 
 direction is downwards, backwards, and a little to the right. 
 It passes behind the duodenum to reach the inner and central 
 part of its descending portion. It accompanies, for a short 
 distance, the pancreatic duct, a groove formed in the sub- 
 stance of the pancreas. It perforates the coats of the duo- 
 denum, as will be seen at another time, obliquely. The 
 ductus choledochus varies much in size in different subjects. 
 It sometimes acquires very great size from the detention of 
 bile. 
 
 The pancreas may be exposed by dividing the descending 
 lamina of the omentum majus a little distance below the 
 convex border of the stomach and turning that organ up- 
 wards. The middle portion of it is brought into view by 
 simply dividing the gastro-hepatic omentum. 
 
 The pancreas is situated behind the stomach, and is covered 
 by the ascending lamina of the transverse meso-colon. It 
 extends from the spleen to the descending portion of the duo- 
 denum, being from six to seven inches in length. The duo- 
 denal extremity, from its size, is sometimes called the head of 
 the pancreas. It fills the concavity of the duodenum, and 
 adheres ctosely to it. The splenic end is named the tail) and 
 the middle part the body. The cceliac artery projects forwards 
 32 
 
374 OF THE ABDOMEN. 
 
 above its upper border, and gives off' the splenic, gastric, and 
 hepatic arteries, both of which run along its upper edge, the 
 former to the spleen, and the latter to the liver. It corresponds 
 behind to the vena portae, the vena cava, the aorta, the crura 
 of the diaphragm, and also to the superior mesenteric artery 
 and vein, which form in it quite a deep sulctis. Its left or 
 splenic extremity rests on the superior extremity of the left 
 kidney and the supra-renal capsule. 
 
 The excretory duct of the pancreas runs the whole length 
 of the gland. It joins the ductus choledochus a short distance 
 before the latter opens into the duodenum, so that the two 
 ducts open by a common orifice. Sometimes there is a small 
 pancreatic duct which opens either into the large one, or sepa- 
 rately. It is better that the duct of the pancreas should be 
 examined, at least partially, before the gland is removed 
 from the abdomen. 
 
 If the pancreas becomes enlarged from disease, it may press 
 upon the vessels beneath it, retarding the circulation through 
 them. The arteries may, at the same time, communicate a 
 pulsatory movement to the tumor, which might give rise to 
 the impression that there was an aneurism. Its relations to 
 the stomach are important. It may, by chronic inflamma- 
 tion, become so agglutinated to the posterior wall of that 
 organ, that when it is perforated by ulceration the pancreas 
 will prevent the escape of its contents. Scirrhus of the pan- 
 creas might be mistaken for that of the pylorus. 
 
 The kidneys are situated in the lumbar regions, the left a 
 little higher than the right. Each lies on the anterior lamina 
 of the fascia lumborum, which separates it from the quad- 
 ratus lumborum muscle, and on the diaphragm by which it 
 is separated from the lower two or three ribs. The ascend- 
 ing colon lies in front of the right, and the descending colon 
 in front of the left. The liver is in relation with the upper 
 extremity of the right, and the spleen with that of the left. 
 Each one is separated from the spine by the psoas magnus, 
 and the right one also by the vertical portion of the duode- 
 num. They are usually surrounded by considerable fat and 
 areolar tissue. Sometimes the peritoneum comes in direct 
 contact with their anterior surfaces ; the colon, in that case, is 
 placed to the inner side of them. The supra-renal capsule is 
 situated on the upper extremity of the kidney. 
 
 The ureters should now be traced from the kidneys into 
 
VESSELS AND NERVES OF ABDOMINAL VISCEEA. 375 
 
 the pelvis. Each, one has a direction downwards and inwards 
 along the psoas magnus, until it reaches the common iliac 
 artery, which it passes over, and also the sometimes external 
 iliac, to enter the pelvis. It is covered by the peritoneum, 
 and has the spermatic vein and artery crossing over, and the 
 genito-crural nerve passing behind it. 
 
 Before the viscera are removed from the abdomen for dis- 
 section, the vessels and nerves which supply them should be 
 carefully examined. The arteries are, the coeliac, the superior 
 and inferior mesenteric, the capsular, and the renal. The 
 veins correspond very nearly to the arteries ; and all of them, 
 except the renal, belong to the portal system. The nerves 
 are derived from the pneumogastric and the sympathetic. 
 
 In the dissection of the vessels of the abdominal viscera, 
 no rule can be laid down for the guidance of the student that 
 will be of much service to him. Before commencing their 
 dissection, he should read carefully a description of each one 
 of them, and ascertain very nearly its origin, position, and 
 direction. He will then be able to place the parts in the 
 position most favorable for getting at and tracing them. In 
 exposing the coeliac artery and its branches, it may be found 
 necessary to change the position of the stomach several times ; 
 and the same may be required in the case of organs concerned 
 in the dissection of other arteries. In tracing the vessels which 
 are distributed to the stomach and intestines, much assistance 
 may be derived from a partial inflation of these organs. 
 
 As the arteries are, for the most part, accompanied by veins 
 and plexuses of nerves which must be dissected at the same 
 time, they will be described in connection. It should be re- 
 marked here, that if the student should wish to acquire a 
 thorough and minute knowledge of the nerves in the abdo- 
 men, he should obtain a subject for this purpose alone. 
 
 The CCELIAC ARTEKY, Fig. 155, 5, and Fig. 159 (2), is given 
 off from the aorta, just below the opening in the diaphragm, 
 and between the crura of that muscle. It is from one-half 
 to three-fourths of an inch in length, and projects almost 
 directly forwards. It is surrounded by the solar plexus, and 
 has one of te semilunar ganglia on each side of it. 
 
 The SOLAR PLEXUS, Fig. 142 (90), consists of a network 
 of nerves, placed in front of the crura of the diaphragm and 
 the aorta, and around the cceliac artery. It receives fila- 
 
376 OF THE ABDOMEN. 
 
 ments from the splanchnic nerves and the right pneumogas- 
 tric nerve. It gives off the hepatic, the splenic, the gastric, the 
 phrenic, the superior mesenteric, and the renal plexuses. Each 
 one of these plexuses should be observed, when the artery 
 which it accompanies is dissected. 
 
 The SEMILUNAK GANGLIA are the largest in the body. 
 They are situated one on each side of the solar plexus, be- 
 hind and above the supra-renal capsule, and resting on the 
 diaphragm and aorta. Although called semilunar, they are 
 very irregular in shape, frequently consisting of several small 
 masses connected by filaments. The great splanchnic nerves 
 terminate in them. They are joined to each other by the 
 solar plexus. 
 
 The coeliac artery has no corresponding vein. It divides 
 into three large branches, the splenic, the gastric, and the 
 hepatic. It is sometimes called the coeliac axis; and'its three 
 branches the tripod of Haller. 
 
 The SPLENIC ARTEKY, Fig. 155, i, runs along the upper 
 border of the pancreas to the hilum of the spleen, where it 
 divides into several branches to be distributed to that organ. 
 It is much longer than the distance from its origin to the 
 spleen, hence it is very tortuous, although nearly horizontal 
 in its general direction. It furnishes branches to the pan- 
 creas and stomach. 
 
 The pancreatic branches are given off to the pancreas as it 
 runs along the upper border of the gland. Near the left ex- 
 tremity, one branch, larger than the others, penetrates the 
 gland, and, joining the duct, accompanies it to the right. 
 
 The left gastro-epiploic, Fig. 155, k, turns to the right, and 
 runs some distance along the convex border of the stomach, 
 where it anastomoses with the right gastro-epiploic artery. 
 In its course it sends branches to both sides of the stomach 
 and to the omentum majus. 
 
 The vasa brevia consist of several branches, which arise 
 from the terminal divisions of the splenic artery. They go 
 to the left extremity of the stomach, where they anastomose 
 with branches of the gastric artery. 
 
 The SPLENIC VEIN, Fig. 157, ~b, commences in the hilum 
 of the spleen, by the union of branches which originate in 
 the cells of that organ. It receives branches which corre- 
 
VESSELS AND NERVES OF ABDOMINAL VISCERA. 377 
 
 spond to those given off by the splenic artery to the stomach 
 and pancreas. The inferior mesenteric vein also empties into 
 
 Fig. 155. 
 
 THE VISCERA OF THE UPPER PART OK THE ABDOMEN, WITH THE CCELIAC ARTERY 
 AND ITS BRANCHES, ARE REPRESENTED IN THIS SKETCH. 1. Liver. 2. GalLbladder. 
 3. Stomach. 4. Its pyloric end. 5. Pancreas. 6. Spleen. 7. Great omentum. 
 A. Aorta, a. Phrenic arterie," b. Coeliac. c. Coronary of stomach, d. Hepatic. 
 e. Superior pyloric. /. Gastro-duodenal. g. Right gastro-epiploic. h. Cystic 
 artery to gall-bladder, i. Splenic, k. Left gastro-epiploic. 
 
 it. It is situated, in its course, behind the splenic artery and 
 the pancreas. It is not tortuous like the artery, but is 
 much larger. It joins the superior mesenteric vein beneath 
 the pancreas, and a little to the left of the ascending vena 
 cava. 
 
 32* 
 
378 OF THE ABDOMEN. 
 
 The SPLENIC PLEXUS is derived from the coeliac or solar 
 plexus. It accompanies the splenic artery, upon which its 
 filaments may be readily traced. It gives off filaments to the 
 pancreas and to the left extremity of the stomach. The 
 latter form the left gastro-epiploic plexus, which accompanies 
 the artery of the same name. The plexus terminates in the 
 substance of the spleen. 
 
 The GASTKIC or SUPERIOR CORONARY ARTERY, Fig. 155, 
 c, passes between the lamime of the gastro-hepatic omentum 
 to the cardiac orifice of the stomach, it then turns to the right 
 and runs along its upper or concave border to near the pylo- 
 rus, where it anastomoses with the superior pyloric, a branch 
 of the hepatic. It gives off branches to both sides of the 
 stomach and to the lower part of the oesophagus. 
 
 The superior coronary vein commences at the lower part of 
 the oesophagus and left extremity of the stomach,' and ac- 
 companies the coronary artery along the upper border of 
 the stomach to the pylorus, where it empties into the vena 
 portaB. It receives in its course branches from both sides of 
 the stomach. 
 
 The coronary plexus is formed by filaments derived from 
 the upper part of the solar plexus, but chiefly from the 
 pneumogastric on the right side. Its filaments are distri- 
 buted to the stomach along with the branches of the coronary 
 artery. 
 
 The HEPATIC ARTERY, Fig. 155, d, goes transversely to 
 the pylorus, and then enters the capsule of Glisson in the 
 right border of the gastro-hepatic omentum, and passes up- 
 wards to the transverse fissure of the liver. It is smaller than 
 the splenic, but larger than the gastric artery. It gives off 
 the following branches : 
 
 The superior pyloric, Fig. 155, e, arises near the pylorus, 
 runs a' short distance on the upper border of the stomach, 
 and anastomoses with the superior coronary artery; it sends 
 twigs to the sides of the stomach. 
 
 The gastro-duodenal, Fig. 155, /, passes downwards be- 
 hind the duodenum near the pylorus, and divides into the 
 pancreatico -duodenal and the right gastro-epiploic. Before 
 it divides, it gives off the inferior pyloric branches to the 
 pylorus. 
 
 The pancreatico-duodenal is distributed to the head of the 
 
VESSELS AND NERVES OF ABDOMINAL VISCERA. 379 
 
 pancreas and the duodenum, between which it runs some 
 distance. It also gives off a branch to anastomose with one 
 from the superior mesenteric artery. 
 
 The right gastro-epiploic, Fig. 155, g, turns to the left, runs 
 along the convex border of the stomach, and anastomoses 
 with the left gastro-epiploic. It gives ascending branches to 
 both sides of the stomach, and descending to the omentum 
 majus. 
 
 The cystic artery, Fig. 155, A, arises from the right division 
 of the hepatic in the transverse fissure of the liver. It goes 
 to the gall-bladder, and divides into two branches, which ra- 
 mify on its sides. 
 
 There is no vein that corresponds to the hepatic artery. 
 The veins which accompany its branches empty into the 
 vena portae. The blood which is conveyed to the liver by 
 the hepatic artery enters plexuses formed by the portal vein 
 in the substance of that organ. 
 
 The HEPATIC PLEXUS follows both the hepatic artery 
 and portal vein to the liver; hence it has been divided 
 into the anterior and posterior plexus. The former is de- 
 rived from both of the semilunar ganglia, and from the 
 right pneumogastric nerve ; the latter comes principally from 
 the left semilunar ganglion. The left pneumogastric nerve 
 sends filaments to join the plexus in the gastro-hepatic 
 omentum. The hepatic plexus ramifies in the substance of 
 the liver, accompanying the divisions of the hepatic artery 
 and portal vein. It also gives off secondary plexuses, which 
 follow the branches of the hepatic artery to the pylorus, the 
 convex border of the stomach, the pancreas, and the gall- 
 bladder. They are named the pyloric, the gastro-duodenal, 
 the right gastro-epiploic^ the paricreatico-duodenal, and the cystic 
 plexuses. 
 
 The SUPERIOR MESENTERIC ARTERY, Fig. 156 (10) and 
 Fig. 159 (9), arises from the aorta just below the coeliac artery. 
 Its origin is concealed by the pancreas, which should be 
 turned upwards and fastened with hooks. It passes down- 
 wards in front of the inferior transverse portion of the duo- 
 denum to the commencement of the attached border of the 
 mesentery, between, the laminae of which it continues down 
 to the junction of tne small with the large intestine. *In its 
 course it forms a curve with the convexity to the left, and 
 
380 
 
 OF THE ABDOMEN. 
 
 the concavity to the right. It supplies the whole of the 
 small intestine with the exception of the upper part of the 
 duodenum, the caecum, the ascending, and about one-half of 
 the transverse colon. Its branches are the following : 
 
 The pancreatico-duodenalisj Fig. 156 (is), is given off be- 
 neath the pancreas. It sends twigs to the pancreas and the 
 duodenum, and anastomoses with a branch of the same name 
 from the hepatic artery. 
 
 The branches to the small intestine, Fig. 156 (16, is), are 
 
 Fig. 156. 
 
 THE COURSE AND DISTRIBUTION OF THE SUPERIOR MESENTERIC ARTERY. 1. 
 The descending portion of the duodenum. 2. The transverse portion. 3. The jeju- 
 num. 4. Thejpancreas. 5. The ileum. 6. The caecum, from which thej appen- 
 dix vermiformis is seen projecting. 7. The ascending colon. 8. The transverse 
 colon. 9. The commencement of the descending colon. 10. The superior niesen- 
 teric artery. 11. The colica media. 12. The branch which inosculates with the 
 colica sinistra. 13. The branch of the superior mesenteric artery, which inosculates 
 with the pancreatico-duodenalis. 14. The colica dextra. 15. The ileo-colica. 16, 
 16. The branhes from the convexity of the superior mesenteric to the small in- 
 testines. 
 
VESSELS AND NERVES OF ABDOMINAL VISCERA. 381 
 
 from fifteen to twenty in number. They arise from the 
 convexity of the artery, and after passing a short distance 
 nearly parallel to each other, between the layers of the me- 
 sentery, each one bifurcates. By the inosculation of these 
 bifurcations with each other, a series of arches, or one con- 
 tinuous arch, is formed, from the convexity of which another 
 set of branches arise. These, much more numerous than 
 those which arise directly from the artery, inosculate with 
 each other, and form a second series of arches, from the con- 
 vexity of which another set of branches arise and inosculate 
 with each other. By the repetition of this process the third, 
 fourth, and sometimes the fifth series of arches are formed 
 by the time the middle portion of the small intestine is 
 reached. Having reached the intestine, the last branches 
 divide into two sets, which ramify on the opposite sides of 
 the bowel ; some of them between the serous and muscular 
 coats ; others perforate the muscular layer, and terminate in 
 the mucous membrane. 
 
 To dissect the arteries to the small intestine, the mesen- 
 tery should be spread out and made tense. It is not neces- 
 sary that the student should dissect all of them, in order to 
 understand their general arrangement. 
 
 The branches to the large intestine arise from the concavity 
 of the main trunk. There are three in number, the ilio- 
 colic, the right colic, and the middle colic. They pass be- 
 tween the layers of the meso-colon, and bifurcate to form a 
 single series of arches, from which branches proceed to the 
 large intestine, upon which they ramify in the same manner 
 as the arteries do on the small intestine. 
 
 The ileo-colic, or inferior colic, Fig. 156 (is), descends to 
 the caecum to divide into branches, to be distributed to the 
 lower part of the ileum, the ca3cum, the appendix vermi- 
 formis casci, and the lower part of the ascending colon. It 
 sends a branch upwards to anastomose with the right colic. 
 
 The right colic, Fig. 456 (14), or, according to some, the 
 middle colic, goes horizontally to the ascending colon, and 
 divides into an ascending and a descending branch, to anas- 
 tomose, the one with the middle colic, and the other with 
 the ileo-colic. 
 
 The middle colic, or the superior colic, Fig. 156 (n), pro- 
 ceeds upwards to the right half of the colon, and like the 
 preceding, divides into two branches. One of these anasto- 
 
382 OF THE ABDOMEN. 
 
 moses with the ascending branch of the right colic, and the 
 other with the left colic branch of the inferior mesenteric 
 artery. 
 
 Fig. 157. 
 
 A VIEW OF THE PORTAL SYSTEM.!. The liver. 2. The stomach. 3. The 
 spleen. 4. The pancreas. 5. A section of the duodenum. 6. The ascending colon. 
 7. The small intestines. 8. The descending colon, a. The portal vein. 6. The 
 splenic vein. c. The right gastro-epiploic. d. The inferior mesenteric. e. The 
 superior mesenteric. /. Section of the superior mesenteric artery. 
 
 The SUPERIOR MESENTERIC VEIN, Fig. 157 (e), corresponds 
 to the artery just described, and originates in that portion 
 of the intestine which is supplied by that artery. Its main 
 trunk passes upwards over the inferior transverse portion of 
 the duodenum, and beneath the pancreas where, in front of 
 the aorta and to the left of the ascending vena cava, it unites 
 with the splenic vein to form the vena portse. Its branches 
 are the same as those of the artery which it accompanies. 
 
VESSELS AND NERVES OF ABDOMINAL VISCERA. 383 
 
 The SUPERIOR MESENTERIC PLEXUS, Fig. 142 (ie), pro- 
 ceeds from the lower part of the solar plexus. The nervous 
 cords in it are large and numerous, forming a sheath for the 
 trunk of the artery. It divides into secondary plexuses, cor- 
 responding to the divisions of the mesenteric artery. In the 
 mesentery, the filaments are long, slender, and straight. Some 
 of them unite to form arches just before they penetrate be- 
 tween the coats of the intestine. This is the largest plexus 
 in the body. 
 
 The INFERIOR MESENTERIC ARTERY, Fig. 155 (n), and 
 158 (9), arises from the aorta, from one to two inches above 
 its bifurcation into the common iliacs. It passes downwards 
 along the aorta, and across the left common iliac, to enter the 
 pelvis. It is much smaller than the superior mesenteric. It 
 supplies the left portion of the transverse colon, the descend- 
 ing colon, the sigmoid flexure, and the upper part of the 
 rectum. In its course it sends off the following branches : 
 
 The left colic artery, Fig. 158 (i o), passes over the left 
 kidney, between the layers of the meso-colon, to the de- 
 scending colon. It divides into an ascending and descend- 
 ing branch. The former anastomoses with the middle colic 
 branch of the superior mesenteric, thus establishing a free 
 anastomotic connection between the two mesenteric arteries ; 
 the latter joins the sigmoid artery below. 
 
 The sigmoid arteries, Fig. 158 (12), proceed transversely 
 to the sigmoid flexure, and divide into branches to anasto- 
 mose above with the left colic, and below with the superior 
 hemorrhoidal. 
 
 The superior hemorrhoidal artery. Fig. 158 (is), passes to 
 the upper part of the rectum, between the laminaB of the 
 meso-rectum. Its branches anastomose with the sigmoid 
 above, and the middle hemorrhoidal below. 
 
 The INFERIOR MESENTERIC VEIN, Fig. 153, d, is formed by 
 branches which correspond to those of the inferior mesenteric 
 artery. A free anastomosis exists between the superior and 
 middle hemorrhoidal veins. It passes upwards to empty into 
 the splenic vein behind the pancreas. Sometimes it opens 
 into the superior meseuteric vein. 
 
 The INFERIOR MESENTERIC PLEXUS, Fig. 142 (te), is de- 
 
384 
 
 OF THE ABDOMEN. 
 
 rived from the aortic plexus. It supplies that portion of the 
 large intestine to which the inferior rnesenteric artery is dis- 
 tributed. 
 
 Fig. 158. 
 
 THE DISTRIBUTION AND BRANCHES OF THE INFERIOR MESENTERIC ARTERY. 1.1. 
 The superior mesenteric artery, with its branches and the small intestines turned 
 over to the right side. 2. The caecum and appendix cgeci. 3. The ascending colon. 
 4. The transverse colon raised upwards. 5. The descending colon. 6. Its sigmoid 
 flexure. 7. The rectum. 8. The aorta. 9. The inferior mesenteric artery. 10. 
 The colica sinistra, inosculating with 11, the colica media, a branch of the superior 
 mesenteric artery. 12, 12. Sigmoid branches. 13. The superior haemorrhoidal 
 artery. 14. The pancreas. 15. The descending portion of the duodenum. 
 
 The SPERMATIC ARTERIES, Fig. 159 (i o), usually arise a 
 little below the renal, from the forepart of the aorta. Each 
 
VESSELS AND NERVES OF ABDOMINAL VISCERA. 385 
 
 descends on the side of the spine, and over the psoas magnus 
 and iliacus internus muscles to the internal inguinal ring, 
 where it joins the spermatic cord. They cross the ureters, 
 and are accompanied by the spermatic veins. In the female, 
 they go to the ovaries, and are called the ovarian arteries. 
 There are sometimes two on the same side. The right one 
 occasionally passes beneath the vena cava. They supply the 
 testicles. 
 
 The SPERMATIC VEINS in the abdomen accompany the 
 spermatic arteries. The left one usually terminates in the 
 renal, and the right one in the ascending vena cava. The 
 latter passes beneath the right and lower portion of the 
 mesentery, and the former beneath the sigmoid meso-colon. 
 
 The SPERMATIC PLEXUS accompanies the spermatic artery 
 to the testicle. In the female, the corresponding plexus fol- 
 lows the ovarian artery to the ovary and the uterus. It is 
 derived from the renal plexus. 
 
 The KENAL ARTERIES, Fig. 159 (7), sometimes called the 
 emulgent arteries, arise from the aorta opposite to the kidneys. 
 They are very large in proportion to the size of the organs 
 which they supply. The right one is longer than the left, 
 and passes beneath the vena cava. The corresponding veins 
 are usually situated in front of them. When the arteries reach 
 the fissures of the kidneys, they divide into several branches. 
 Sometimes, instead of one there will be two or three on the 
 same side. They are also subject to considerable variation in 
 their origin. 
 
 The EENAL VEINS convey the venous blood from the 
 kidneys to the ascending vena cava. The left is the longest, 
 and passes over the aorta ; it also receives the left spermatic 
 vein. The veins are in front of the corresponding arteries. 
 They open into-ahe vena cava at right angles. The supra- 
 renal vein on the left side usually opens into the renal of the 
 same side. 
 
 The KENAL PLEXUS, Fig. 142 (14), is formed on each side 
 by filaments from the solar plexus and from the lesser 
 splanchnic nerve. It accompanies the renal artery to the 
 kidney. 
 
 The SUPRA-RENAL ARTERIES, Fig. 159 (e), arise from the 
 33 
 
386 
 
 OF THE ABDOMEN. 
 
 sides of the aorta, sometimes from the phrenic or renal. They 
 supply the supra-renal capsules and the surrounding adipose 
 tissue. 
 
 Fig. 159. 
 
 THE ABDOMINAL AORTA WITH 
 ITS BRANCHES 1. The phrenic 
 arteries. 2. The coeliac axis. 
 3. The gastric artery. 4. The 
 hepatic artery, dividing into 
 the right and left hepatic 
 branches. 5. The splenic ar- 
 tery, passing outwards to the 
 spleen. 6. The supra-renal ar- 
 tery of the right side. 7. The 
 right renal artery, which is 
 longer than the left, passing 
 outwards to the right kidney. 
 8. The lumbar arteries. 9. The 
 superior mesenteric artery. 10. 
 The two spermatic arteries. 11. 
 The inferior mesenteric artery. 
 12. The sacra media. 13. The 
 common iliacs. 14. The in- 
 ternal iliac of the right side. 
 
 15. The external iliac artery. 
 
 16. The epigastric artery. 17. 
 The circumflex ilii artery. 18. 
 The femoral artery. 
 
 The SUPKA-KENAL VEINS open, the right into the vena 
 cava, and the left into the renal vein. 
 
 DISSECTION OF THE VISCERA. 
 
 The viscera which have been examined in situ, can now be 
 removed from the abdomen for the purpose of dissecting 
 them, and studying their structure. The small intestine 
 below the duodenum, and the large* above the rectum, 
 
THE STOMACH. 
 
 387 
 
 should be removed first. To do this, apply two ligatures 
 *around the jejunum, at its commencement, and also two 
 around the lower end of the sigmoid flexure of the colon, 
 and divide the intestine between the ligatures at each place. 
 To detach them will require a division of the mesentery, the 
 meso-csecum, and the meso-colon, including the omentum 
 majus. These may be laid aside until the stomach and duo- 
 denum have been removed and examined. 
 
 To remove the stomach, apply two ligatures to the duode- 
 num, about an inch from the pylorus, and divide it between 
 them ; then apply a ligature to the oesophagus as it passes 
 through the diaphragm, and divide it above the ligature. 
 The spleen may be taken out with the stomach, or by 
 itself. The pancreas and the remaining portion of the duo- 
 denum should be removed together. In dissecting them out, 
 care should be taken not to injure the aorta and vena cava. 
 
 The stomach and the intestines should be emptied of their 
 contents, and thoroughly cleansed before they are examined. 
 This may be done by filling them repeatedly with water, or 
 by allowing the water to flow through them from the stop- 
 cock of a hydrant. 
 
 THE STOMACH. 
 
 To study the external appearance of the stomach it should 
 be inflated. It has a 
 
 conical form, being curv- Fi S- 16 
 
 ed upon itself. Its apex 
 is cylindrical, and joins 
 the duodenum, where 
 there is a slight constric- 
 tion. Its base is rounded, 
 and projects from two to 
 three inches beyond the 
 cardiac orifice. This por- 
 tion has been designated 
 the great cul-de-sac, or 
 great tuberosity, Fig. 160, c, DlAflRiM OOTLINE op ^^^ Sreat 
 
 01 the Stomach. .Near curvature, b. Lesser curvature, c. Left end, 
 
 the pvloric extremitV great cul - de - sac or fundus. d. Small cul-de- 
 
 i y ' sac or antrum pylori, o. (Esophaeeal orifice 
 
 and On the Convex Side, orcardia. q . Duodenal orifice or pylorus. 
 
388 OF THE ABDOMEN. 
 
 is a dilatation called the small cul-de-sac, Fig. 160, d. Instead of 
 there being a constriction around the cardiac orifice, as there* 
 is around the pyloric, the oesophagus expands somewhat as it 
 joins the walls of the stomach. 
 
 The stomach is everywhere covered by peritoneum, except 
 a narrow space along each of its borders where the laminas 
 of the greater and lesser omenta are separated for the trans- 
 mission of vessels and nerves. This space is diminished in 
 size when the stomach is distended. 
 
 Perhaps no organ in the body is subject to greater varia- 
 tion in size than the stomach. This is owing, probably, in 
 a great measure, to the habits of the individual in regard to 
 eating. Its coats being very dilatable, yield to a distending 
 force, which may be exerted by the introduction of large 
 quantities of food into the stomach until it has acquired an 
 enormous capacity. It is not unfrequently found very much 
 contracted in the dead subject. It also varies considerably 
 in its relative dimensions, being much longer and narrower 
 in some cases than in others. 
 
 The stomach has four different layers in its parietes. 
 These differ from each other in structure and in function. 
 In addition to these, it has bloodvessels, nerves, and lym- 
 phatics. The layers are a mucous, a fibro-cellular, a mus- 
 cular, and a serous or peritoneal. 
 
 The SEEOUS COAT, as has been seen, is a portion of the 
 peritoneum. It furnishes to the stomach a perfectly smooth 
 surface, which is constantly lubricated with a serous exhala- 
 tion which prevents the occurrence of friction in its move- 
 ments on contiguous surfaces. It also adds strength to its 
 parietes, and, by its reflections, assists in keeping it in its 
 place. 
 
 The MUSCULAR COAT consists of longitudinal, circular, 
 and oblique fibres. To expose these, the serous layer should 
 be removed while the stomach is distended with air. This 
 is to be done partly by tearing and partly by dissecting it 
 off. Frequently, when the stomach is inflated, the fibres can 
 be very distinctly seen without any dissection. This is the 
 case, especially when the muscular layer is strongly deve- 
 loped. The muscular fibres of the stomach belong princi- 
 pally to the non-striated or involuntary class. 
 
THE STOMACH. 389 
 
 The longitudinal fibres, Fig. 161 (e), are placed next to the 
 serous coat. If a portion of the oesophagus be inflated with 
 
 A FRONT VIEW OF THE STOMACH, DISTENDED BY Am, WITH THE PERITONEAL 
 COAT TURNED OFF. 1. Anterior face of the oesophagus. 2. The cul-de-sac, or 
 greater extremity. 3. The lesser or pyloric extremity. 4. The duodenum. 5, 5. 
 A portion of the peritoneal coat turned back. 6. A portion of the longitudinal 
 fibres of the muscular coat. 7. The circular fibres of the muscular coat. 8. The 
 oblique muscular fibres, or muscle of Gavard. 9. A portion of the muscular coat 
 of the duodenum, where its peritoneal coat has been removed. 
 
 the stomach, they will be seen to be a continuation of the 
 longitudinal fibres of that tube. They are most numerous 
 along the concave border and near the pylorus, from which 
 they are continued on to the small intestine. 
 
 The circular fibres, Fig. 161 (7), pass round the circum- 
 ference of the stomach from the cardiac to the pyloric orifice. 
 They increase in number tov7ards the pylorus. Around the 
 pyloric orifice they are collected into a sphincter which is 
 capable of closing that opening, so as to prevent the passage 
 of the contents of the stomach into the duodenum during 
 the time of its contraction. 
 
 The oblique fibres, Fig. 161 (e), which are sometimes ab- 
 sent or very indistinct, pass from one side of the stomach to 
 the other around the great cul-de-sac to the left of the car- 
 diac orifice. 
 
 The FIBRO-CELLULAR COAT is placed between the muscu- 
 
 33* 
 
390 
 
 OF THE ABDOMEN. 
 
 lar and mucous, to the former of which it is closely con- 
 nected by processes which are sent in between its fibres. 
 The arteries and nerves, after passing through the muscular 
 coat, ramify in this. By its density and intimate connection 
 with the muscular layer, it contributes much to the strength 
 of the walls of the stomach. It has been regarded by some 
 as the framework of this organ. 
 
 The Mucous COAT, Fig. 162, should be examined when 
 the stomach is everted and inflated, and also when everted 
 but not distended. It glides freely on the nbro-cellular 
 layer to which it is applied, and hence when the stomach is 
 empty and contracted, it is thrown into numerous folds or 
 rugce, which disappear again when the organ is distended. 
 The principal part of these folds have a longitudinal direction. 
 There are, however, some which intersect these obliquely, 
 and others transversely. 
 
 At the cardiac orifice, when the stomach is empty, the 
 folds of the mucous membrane ^present a stellated appear- 
 
 Fig. 162. 
 
 A VERTICAL AND LONGI- 
 TUDINAL SECTION OF THE 
 STOMACH AND DUODENUM, 
 MADE IN SUCH A DIRECTION 
 AS TO INCLUDE THE TWO 
 ORIFICES OF THE STOMACH. 
 1. The oesophagus : upon 
 its internal surface the pli- 
 cated arrangement of the cu- 
 ticular epithelium is shown. 
 2. The cardiac orifice of the 
 stomach, around which the 
 fringed border of the cuti- 
 cular epithelium is seen. 3. 
 The great end of the sto- 
 mach. 4. Its lesser or pylo- 
 ric end. 5. The lesser curve. 
 6. The greater curve. 7. 
 The dilatation at the lesser 
 end of the stomach, which 
 has received from Willis the 
 name of antrum of the py- 
 lorus. This may be regarded as the rudiment of a second stomach. 8. The rugse 
 of the stomach, formed by the mucous membrane : their longitudinal direction is 
 shown. 9. The pylorus. 10. The oblique portion of the duodenum. 11. The 
 descending portion. 12. The pancreatic duct and the ductus communis choledo- 
 chus close to their termination. 13. The pnpilla upon which the ducts open. 14. 
 The transverse portion of the duodenum. 15. The commencement of the jejunum. 
 In the interior of the duodenum and jejunum the valvula? conniventes are seen. 
 
THE STOMACH. 
 
 391 
 
 ance, and where the mucous membrane of the oesophagus 
 joins that of the stomach, its epithelium exhibits a fringed or 
 festooned border, Fig. 162 (2). There is no circular fold or 
 sphincter muscle at this orifice as there is at the pyloric, where 
 the mucous membrane projects inwards from the circumfer- 
 ence of the opening between the stomach and the duodenum, 
 so as to form a partial septum between the cavities of these 
 organs. With the aid of the circular fibres contained be- 
 tween the laminae of this fold, it is capable of closing the 
 orifice which it surrounds. If the stomach and duodenum 
 be inflated and dried, a good view of this fold, with the cir- 
 cular aperture in its centre, may be obtained. The lamina) 
 of which it is composed resemble, in their organization, the 
 one the gastric, the other the duodenal mucous membrane. 
 
 The color of the mucous membrane of the stomach varies 
 in health as well as in disease. In the very young, it has a 
 bright reddish tint, while in the aged it usually presents a 
 dark-grayish appearance. It is found of a brighter red if 
 death has occurred when it was full and during the process 
 of digestion than if when empty and free from vascular ex- 
 citement. Its color is also frequently modified by the pre- 
 sence of bile, or by the action of the gastric juices. 
 
 The mucous membrane has not the same 
 thickness and vascularity in every part of 
 the stomach; being thicker towards the 
 pyloric, and more vascular towards the 
 cardiac orifice. There seems to be, also, 
 some difference in susceptibility to disease 
 in its right and left portions. 
 
 Papillce may be observed with the aid 
 of a lens on the mucous surface in all 
 parts of the- stomach. They are more 
 numerous, however, in the pyloric than 
 in the cardiac extremity. They are sepa- 
 rated from each other by cells, or alveoli, 
 in which may be seen the mouths of 
 small tubes. These tubes are lined by 
 a columnar epithelium. They are sup- 
 posed to secrete the gastric juices. 
 
 The vessels and nerves of the stomach 
 were examined before it was removed from the abdomen. 
 
 Fig. 163. 
 
 VIEW OF THE CELLS 
 OF THE MUCOUS MEM- 
 BRANE OF THE HUMAN 
 STOMACH, MAGNIFIED 
 32 DIAMETERS. After 
 Dr.SprottBoyd. The 
 hexagonal cells with 
 their intermediate ele- 
 vated margins, and the 
 mouths of the tubuli 
 at the bottom of each, 
 are shown. 
 
392 
 
 OF THE ABDOMEN. 
 
 TPIE SMALL INTESTINE. 
 
 The small intestine is divided into three portions : the duo- 
 denum, the jejunum, and the ileum. This division is wholly 
 arbitrary, and practically is of little value. The small in- 
 testine is about twenty feet in length. It diminishes in size, 
 and in the thickness of its coats, from its commencement to 
 its termination. Its structure is similar to that of the stomach, 
 being composed of a serous, a muscular, a cellular, and a 
 mucous coat. 
 
 The SEROUS COAT consists principally of a single dupli- 
 
 cature of the peritoneum, be- 
 tween the lamina? of which 
 the vessels and nerves reach 
 the intestine along its con- 
 cave or attached border. 
 The duodenal portion of the 
 intestine is not entirely in- 
 vested with a serous layer, 
 as was observed in the ex- 
 animation of it in situ. 
 
 rm -,r T 
 
 The . MUSCULAB LAYER 
 
 Fig. 164. 
 
 A VIEW OP THE MUSCULAR COAT OP THE 
 
 ILEUM. 1. 1. The peritoneal coat. 2. A 
 portion of this coat turned off and show- 
 
 ing a portion of the longitudinal fibres of Fig. 164, is Composed of a 
 
 the muscular coat adherent to it. 3,4,5. 
 The circular muscular fibres in different 
 
 parts of the intestine. set of fibres. The action of 
 
 the bowel in propelling for- 
 
 ward its contents, depends mainly on the circular fibres, which 
 are much more numerous than the longitudinal. They do 
 not, all of them at least, extend entirely around the circum- 
 ference of the intestine. To obtain a good view of the longi- 
 tudinal fibres, a section of the intestine should be inflated, 
 and the peritoneum carefully dissected or peeled off. They 
 will be found more numerous on the convex than on the con- 
 cave border of the bowel. 
 
 The CELLULAR LAYER is interposed between the mus- 
 cular and mucous layers, between which it forms a bond of 
 union, allows the latter to glide freely on the former, and 
 furnishes a medium for the transmission and subdivision of 
 the vessels and nerves supplied to the mucous membrane. 
 
THE SMALL INTESTINE. 393 
 
 This layer can be very satisfactorily demonstrated by evert- 
 ing a portion of the intestine and then forcibly distending it 
 with air. The preparation should be dried, and the mucous 
 membrane afterwards removed. 
 
 The Mucous MEMBEANE of the small intestine should be 
 carefully observed by the student. He should become per- 
 fectly familiar with the appearance of it as seen in the dis- 
 secting room, where he will have an opportunity of examining 
 it in a healthy as well as in a diseased condition. The follow- 
 ing should be particularly noticed: The valvulse conniventes, 
 the common orifice of the pancreatic and biliary ducts, the 
 villi, the glands of Lieberkiihn, Brunner, Peyer, and the 
 glandule solitarise. 
 
 The YALVUL^E CONNIVENTES, Fig. 162 (15), are perma- 
 nent, crescentic folds of the mucous membrane, extending 
 from one-half to two-thirds around the circumference of the 
 intestine. They are most prominent in the lower part of the 
 duodenum and in the jejunum, while in the upper part of the 
 duodenum and in the lower part of the ileum they are usu- 
 ally absent. They increase the extent of mucous surface, and 
 also serve to retard the passage of the food through, the in- 
 testine. 
 
 The ORIFICE of the ductus choledochus communis, and the 
 pancreatic duct, Fig. 162 (is), is situated on the summit of a 
 small eminence at the lower part of the descending portion 
 of the duodenum, and about three inches and a half from the 
 pylorus. It is readily observed when the duodenum is everted, 
 or when a probe is carried through the biliary duct. These 
 ducts sometimes open into the intestine separately. The 
 biliary duct is slightly constricted near its orifice. After 
 perforating the muscular coat, the two ducts run half an inch 
 or more between it and the mucous membrane, before open- 
 ing into the duodenum. When the intestine is inflated, air 
 will not pass into these ducts on account of the mucous mem- 
 brane being pressed against the muscular layer. 
 
 The VILLI, Fig. 165, are small vascular eminences, which 
 are found on the mucous surface of the whole of the small 
 intestine. They vary from one-fifth to four-fifths of a line in 
 length. They are most numerous in the duodenum and jeju- 
 num where the valvulae conniventes are most prominent. 
 
394 OF THE ABDOMEN. 
 
 Some of them have a conical form, while others have a 
 flattened or triangular shape. They give to the internal 
 surface of the intestine a velvety appearance. They consist 
 of projections of the mucous membrane, covered by epithe- 
 lium, and contain a network of capillary vessels, and lacteals 
 or absorbent vessels. They are very distinctly seen, when a 
 portion of the intestine is minutely injected and allowed to 
 float in water or alcohol. 
 
 The GLANDS, or FOLLICLES OF LIEBERKUHN, are small 
 crypts found in every part of the small intestine. They are 
 situated between the villi and around the larger glands. They 
 are similar to the small tubuli observed in the mucous mem- 
 brane of the stomach. 
 
 The GLANDS OF BRUNNER are small glandular bodies, 
 situated in the cellular coat of the duodenum, forming small 
 projections on the surface of the mucous membrane. They 
 are about the size of hemp seed. Each gland is composed of 
 several lobules, which open on the mucous surface through a 
 common duct. In structure they resemble the salivary glands. 
 
 The GLANDULE SOLITARY, Fig. 165, are small projecting 
 bodies, observed along the whole track of 
 Fig. 165. the small intestine. They are covered 
 
 by villi, and surrounded by the crypts of 
 Lieberkiihn. They have no excretory 
 ducts, or open mouths. When they- are 
 cut into they are found to contain a 
 whitish, granular substance. Their use 
 is not known. 
 
 The GLANDS OF PEYER, Fig. 166, or 
 SOLITARY GLAND OP the glanduloe. agminatce, are observed 
 "^ '(Zb-i Principally in the lower portion of the 
 The surface is beset with ileum, and on the side opposite to the 
 villi: the mouths of nu- attachment of the mesentery. They con- 
 
 merous crypts of Lieber- . t .-, . . J ij? 
 
 kUhn are also seen. sist of patches varying in number from 
 
 ten to thirty, or more, of an oval or ob- 
 long shape, being from one to two or three inches in length, 
 and half an inch in breadth. They have no excretory ducts. 
 Each patch is supposed to be an aggregation of the solitary 
 glands, and, like them, their function has not been ascer- 
 tained. To examine them, the intestine should be laid open 
 
THE LAKGE INTESTINE. 
 
 395 
 
 Fig. 166. 
 
 ENLARGED VIEW OF A PART OF 
 A PATCH OF PETER'S GLANDS. 
 It shows the different forms of the 
 individual vesicles, the zone of 
 foramina belonging to Lieber- 
 kiihn's follicles around each, the 
 mouths of other of those follicles 
 and numerous villi situated be- 
 tween the vesicles, not upon them, 
 and, lastly, the surrounding dark- 
 er part of the mucous membrane 
 beset merely with villi and fol- 
 licles. 
 
 along its concave or attached border, and the mucus being 
 carefully washed off, should then be held before a strong light. 
 
 THE LARGE INTESTINE. 
 
 The location and the relations of the large intestine, except 
 the rectal portion, have been described. Its caliber is much 
 larger than that of the small intestine. It is largest at its 
 commencement, and gradually diminishes in size to the lower 
 part of the rectum, where, just above the anus, a pouch or 
 dilatation exists. The external appearance of the large is 
 quite different from that of the small intestine. Instead of 
 being smooth and cylindrical, it presents, except the rectum, 
 a sacculated appearance, the pouches being arranged longitu- 
 dinally in three series, and separated by the same number 
 of smooth surfaces extending the whole length of the caecum 
 and colon. 
 
 To dissect the large intestine, it should be removed, as 
 before mentioned, from the abdomen and inflated. As the 
 rectum cannot be examined until the soft parts of the pelvis 
 are dissected, it will be necessary to apply a ligature to the 
 upper part of the rectum, and divide the intestine just above 
 it. A small portion of the ileum should be removed with 
 the caecum and colon. 
 
 With the exception of the lower part of the rectum, the 
 large intestine has the same number of layers in its parietes 
 as the small. 
 
396 
 
 OF THE ABDOMEN. 
 
 A part of the transverse colon is placed between the two 
 ascending layers of the omentum majus, and it consequently 
 has, like the stomach, two non-peritoneal surfaces. The peri- 
 toneum on the caecum and colon presents numerous small 
 pouches rilled with fat. The length of these is diminished when 
 the bowel is inflated. They are called appendices epiploicce. 
 
 The longitudinal muscular fibres in the ccecum and colon 
 are collected into three bands, which correspond to the smooth 
 surfaces between the pouches. They commence at the ap- 
 pendix vermiformis caeci, and terminate at the rectum. The 
 sacculated form of the large intestine is caused by the rela- 
 tive shortness of- these bands. The circular fibres are most 
 numerous in the ridges which project into the intestine be- 
 tween the sacculi. 
 
 The cellular coat requires no special notice. It separates 
 
 the mucous from the muscular 
 Fig. 167. coat in the same manner as 
 
 the corresponding layer does 
 in the small intestine. 
 
 The mucous coat has a pale 
 appearance. It has no folds 
 corresponding to the valvulas 
 conniventes in the small in- 
 testine. The projections be- 
 tween the sacculi are formed 
 of all the layers except the 
 longitudinal fibres of the 
 muscular coat. It has very 
 few if any villi. It has alveoli 
 similar to those observed in 
 the stomach. It is every- 
 where thickly studded with 
 the orifices of follicles or tu- 1 
 buli, which resemble those 
 of Lieberkiihn in the small 
 intestine. There are also 
 found scattered over its sur- 
 face, crypts or follicles, of a 
 large size. These consist of 
 
 A VIEW OP THE POSITION AND CURVA- 
 TURES OP THE LARGE INTESTINE. 1. 
 The end of the ileum. 2. Appendix 
 vermiformis. 3. The caecum, or caput 
 
 coli. 4. The transverse colon. 5. The . , 
 
 descending colon. 6. The sigmoid flex- Small pouches With COntract- 
 ure. 7. Commencement of rectum. 8, 8. e( J orifices, opening On the 
 The rectum. 9. The .anus. The levator 
 ani muscle is seen 011 each side. 
 
 mucous surface. They are 
 
THE LARGE INTESTINE. 
 
 397 
 
 Fig. 168. 
 
 more numerous in the caecum and appendix vermiformis than 
 elsewhere. These follicles -may be inflamed without involv- 
 ing other parts of the mucous membrane. 
 
 The APPENDIX VERMIFORMIS C.ECI, Fig. 168 (5), has the 
 same number of layers in its walls as the intestine. It opens 
 into the ca3cum by an orifice about the size of a goose-quill. 
 Sometimes a valvular fold of mucous membrane is found 
 situated at this opening. Foreign bodies sometimes pass into 
 it, and give rise to inflammation and ulceration of its coats. 
 It is not known to have any function. 
 
 The ILEO-C^CAL VALVE, Fig. 168 (3), or the valve of Bau- 
 hin, is placed at the opening of the small into the large intes- 
 tine. It consists of two folds of the mucous membrane, in- 
 cluding areolar tissue and a layer 
 of muscular fibres. The upper 
 fold is sometimes called the ileo- 
 colic valve. They project into the 
 large intestine so as to form a 
 slit between their free borders. 
 This slit is placed transversely 
 to the large intestine between the 
 caecum and colon, and looks more 
 into the latter than into the for- 
 mer. A fold of mucous mem- 
 brane is extended from each 
 commissure for some distance on 
 the inner surface of the intestine ; 
 they have been named thefrcena 
 of the valve. The lower fold, or 
 ileo-ccecal valve, is somewhat larger 
 than the ileo-colic. The shape of 
 the aperture between the valves 
 depend very much on the man- 
 ner in which the peritoneum is 
 reflected from the small to the 
 
 large intestine. AND LAID OPEN IN FRONT. 1. The 
 
 The mucous membrane of the pending colon. 2 One of the 
 
 ., . - cells of the colon. 3. The ileo-csecal 
 
 lleum IS Continued to the tree valve. 4. The opening into the 
 
 borders Of the Valves where that appendix vermiformis cjeci. 5. Ap- 
 
 o , i -i -, pendix vermiformis cseci. 6. A sec- 
 
 ot the caecum and colon com- tion of the lower end of the ileum . 
 34 
 
398 OF THE ABDOMEN. 
 
 mences. In this respect these valves resemble the one be- 
 tween the stomach and duodenum. When these valves are 
 closed the contents of the large intestine cannot pass into 
 the small. 
 
 To obtain a good view of these valves and the opening 
 between them, the student should innate and dry the caecum 
 and a portion of the colon and ileum, and then cut away a 
 part of the former. 
 
 THE DISSECTION OF THE LIVER. 
 
 To dissect and study the liver, it should be removed from 
 the abdomen. To do this it will be necessary to divide the 
 ligaments or folds of peritoneum which attach this organ 
 to the diaphragm, and also to remove a portion of the ascend- 
 ing vena cava with it. Care should be observed not to in- 
 jure the diaphragm in this dissection. 
 
 The liver presents, for examination, an upper anterior, 
 and an inferior posterior surface, a posterior and an anterior 
 border, and a right and left extremity. 
 
 It is the largest gland in the body. Its weight varies from 
 two to five pounds. Both its weight and size, however, will 
 depend much on the amount of blood contained in its vessels. 
 Its size is also greatly modified by disease. In some instances 
 it has been found to weigh from twenty-five to thirty pounds, 
 while in others its weight did not exceed a pound. It has a 
 reddish brown color ; but in this respect it varies very much 
 in different subjects, and especially when diseased. It is 
 fragile, and easily broken when pressed between the thumb 
 and finger. Owing to its brittleness, it is liable to be lacerated 
 by blows inflicted on the abdomen. 
 
 The upper anterior surface of the liver is convex, and 
 moulded to the concavity of the diaphragm. The attach- 
 ment of the suspensory ligament divides it into a right and 
 left surface, corresponding -to the right and left lobes. 
 
 The posterior border is rounded, thick at its right, and thin 
 at its left extremity. The anterior border is thin, presenting 
 quite a sharp edge. The right extremity is thick behind and 
 thin anteriorly. The left extremity is thin. It will be ob- 
 served that the posterior and right portion of the liver is the 
 thickest part of it. 
 
DISSECTION OF THE LIVER. 399 
 
 The inferior posterior surface, Fig. 169, is irregularly con- 
 cave. It presents, usually, indentations for the right kid- 
 ney, the colon, and the stomach. It has three fissures ; two 
 of which extend from the anterior to the posterior border. 
 These last are named the right and left antero-posterior fissures. 
 The left antero-posterior is sometimes called the longitudinal 
 fissure, Fig. 169 (s). It indicates the line of division between 
 the right and left lobes of the liver on its under surface. 
 The remaining one connects these two, and is called the trans- 
 verse fissure, Fig. 169 (is). The antero-posterior fissures are 
 separated anteriorly by the lobus quadratus, Fig. 169 (24), and 
 posteriorly by the lobus Spigelii, Fig. 169 (25), while the 
 lobes themselves are separated from each other by the trans- 
 verse fissure. The right antero-posterior fissure is interrupted 
 just behind the transverse fissure, by a process extending 
 from the lobus Spigelii to the under surface of the right 
 lobe; this process is called the lobus caudatus, Fig. 169 (ae). 
 
 The right antero-posterior fissure is occupied anteriorly 
 by the gall-bladder, and posteriorly by the vena cava. The 
 left antero-posterior fissure contains, anteriorly, the remains 
 
 Fig. 169. 
 
 THE INFERIOR OR CON- 
 CAVE SURFACE OF THE LI- 
 VER, SHOWING ITS SUBDI- 
 VISIONS INTO LOBES. 1. 
 Centre of the right lobe. 
 
 2. Centre of the left lobe. 
 
 3. Its anterior, inferior, or 
 thin margin. 4. Its poste- 
 rior, thick, or diaphragma- 
 tic portion. 5. The right 
 extremity. 6. The left ex- 
 tremity. 7. The notch on 
 the anterior margin. 8. 
 The umbilical or longitudi- 
 nal fissure. 9. The round 
 ligament or remains of the 
 umbilical vein. 10. The 
 portion of the suspensory li- 
 gament in connection with the round ligament 11. Pons hepatis, or band of liver 
 across the umbilical fissure. 12. Posterior end of longitudinal fissure. 13, 14. 
 Attachment of the obliterated ductus venosus to the ascending vena cava. 15. 
 Transverse fissure. 16. Section of the hepatic duct. 17. Hepatic artery. 18. Its 
 branches. 19. Vena portae. 20. Its sinus, or division into right and left branches. 
 21. Fibrous remains of the ductus venosus. 22. Gall-bladder. 23. Its neck. 24. 
 Lobus quadratus. 25. Lobus Spigelii. 26. Lobus caudatus. 27. Inferior vena 
 cava. 28. Curvature of liver to fit the ascending colon. 29. Depression to fit the 
 right kidney. 30. Posterior portion of its right concave surface over the re- 
 nal capsule. 31. Portion of liver uncovered by the peritoneum. 32. Inferior edge 
 of the coronary ligament in the liver. 33.* Depression made by the vertebral 
 column. 
 
400 
 
 OF THE ABDOMEN. 
 
 of the umbilical vein of the foetus, and posteriorly, the remains 
 of the ductus venosus. The transverse fissure is occupied by 
 the capsule of Glisson, the portal vein, the hepatic artery and 
 duct, the hepatic plexus of nerves, and the deep absorbent 
 vessels. 
 
 The pons hepatis, Fig. 169 (i i), when present, consists of a 
 portion of the substance of the liver, extending across the 
 left antero-posterior fissure beneath the ligamentum teres. 
 
 The mouths of the hepatic veins will be observed opening 
 into the vena cava behind the lobus Spigelii, on the pos- 
 terior border of the liver. There are usually three or four 
 of these veins. 
 
 The capsule of Glisson is a dense areolar tissue which sur- 
 rounds the vessels in the transverse fissure, and is prolonged 
 into the substance of the liver, forming sheaths, named portal 
 canals, Fig. 170, a, a, for these vessels; it also forms the 
 proper capsule of the entire organ, as well as an investment 
 
 SECTION OF A PORTAL CANAL 
 AND PORTAL VEIN LYING IN IT, IN 
 
 COMPANY WITH THE HEPATIC AR- 
 TERY AND DUCT. P. Branch of ve- 
 na portse, situated in a, a, a portal 
 canal, formed amongst the lobules 
 of the liver. The large orifices 
 opening into the portal vein are 
 the mouths of the vaginal branches. 
 b. Orifices of interlobular veins, 
 arising at once from the large vein. 
 A. Hepatic artery. D. Hepatic 
 duct. 
 
 for its lobules or acini. The inner surface of the portal 
 canals is connected to the vessels by loose areolar tissue, 
 while the external surface is closely connected to the sub- 
 
DISSECTION OF THE LIVEK. 
 
 401 
 
 stance of the liver by numerous prolongations sent off be- 
 tween the lobules. 
 
 The student should trace the portal vein, the hepatic artery 
 and duct, or, at least, their principal divisions, in the substance 
 of the liver ; also the hepatic veins. 
 
 The vena portce enters the transverse fissure of the liver 
 and divides into a right and left branch, forming at this di- 
 vision the portal sinus. The branches enter the liver, and 
 divide and subdivide until every part of the organ is reached. 
 The subdivisions of it are named, the vaginal, the interlobular, 
 and the lobular. 
 
 The hepatic artery enters the liver with the vena portae, 
 and divides into the same number of branches as it. Its 
 subdivisions are named the vaginal, the interlobular, and the 
 lobular. 
 
 The hepatic duct accompanies the vein and artery in its 
 
 Fig. 171. 
 
 II. Longitudinal section of 
 an hepatic vein. a, a. Por- 
 tions of the canal from which 
 the vein has been removed. 
 b, b. Orifices of intralobular 
 veins. The large orifices open- 
 ing into the hepatic vein are 
 the mouths of the sublobular 
 veins. 
 
 minute divisions, which have the same names. The spaces 
 occupied by the portal vein, artery, and duct, are called the 
 portal canals. 
 
 34* 
 
402 OF THE ABDOMEN. 
 
 The hepatic veins, Fig. 171, H, commence in the lobules by 
 the intrakbular veins, which end in the sublobular, and these 
 again terminate in the hepatic veins, of which there are, 
 commonly, three or four principal trunks. These open into 
 the vena cava near the diaphragm. They are not surrounded 
 by areolar tissue like the portal vein, but adhere closely to 
 the canals, the walls of which are very thin, and conse- 
 quently do not collapse when they are divided. 
 
 A branch of an hepatic vein is readily distinguished from 
 one of the portal vein; as the latter is always accompanied 
 by a branch of the hepatic artery and duct, is surrounded 
 by areolar tissue, collapses when divided, and is directed 
 towards the transverse fissure. Neither the portal nor the 
 hepatic veins have any valves. 
 
 The nerves and the deep lymphatics of the liver accompany 
 the divisions of the hepatic artery and portal vein. 
 
 The proper substance of the liver consists of small granu- 
 lar polyhedral bodies named lobules. Each one is about the 
 size of a millet seed, and represents, in miniature form, the 
 entire liver. It is invested by a process from the capsule of 
 Glisson, except at its base, where it rests on a sublobular 
 vein. 
 
 DISSECTION OF THE GALL-BLADDEK. 
 
 The gall-bladder, Fig. 169 (22), and Fig. 172, is attached to 
 the under surface of the right lobe of the liver, and occupies 
 the anterior portion of the right antero-posterior fissure. It 
 is of a conical form. The base is directed downwards, for- 
 wards and to the right ; sometimes it projects beyond the 
 anterior border of the liver, and again does not extend to it. 
 The apex is directed backwards, upwards, and to the left, 
 where it ends in the cystic duct. It is subject to much vari- 
 ation in size. 
 
 Its free surface is covered by peritoneum, which is reflected 
 from it to the liver. Its adherent surface is in contact with 
 the substance of the liver, from which it is easily separated 
 after the peritoneum has been divided around it. It has a 
 fibro-cellular coat, which in some of the larger animals con- 
 tains non-striated muscular fibres. The mucous membrane 
 presents a honey -combed or reticulated appearance. It is 
 stained with bile after death. 
 
DISSECTION OF THE GALL-BLADDER. 
 
 403 
 
 The neck of the gall-bladder is doubled twice upon itself. 
 This is caused principally by the manner in which the peri- 
 toneum is attached to it. On the inside of the neck, Fig. 172 
 
 Fig. 172. 
 
 SHOWS THE THREE COATS 
 OF THE GALL-BLADDER SE- 
 PARATED FROM EACH OTHER. 
 1. The external or perito- 
 neal coat, 2, 2. The cellular 
 coat with its vessels injected. 
 3, 3. The mucous coat co- 
 vered with wrinkles. 4, 4. 
 Valves formed by this coat 
 in the neck of the gall-blad- 
 der. 5, 5. Orifices of the 
 mucous follicles at this point. 
 
 (4, 4), the coats project inwards so as to form two or three 
 folds, which resemble valves. They do not, however, inter- 
 fere with the passage of the bile in either direction. 
 
 The cystic duct, Fig. 173,/, is about an inch and a half in 
 length. It unites with the hepatic duct to form the ductus 
 choledochus communis. Its inner surface presents from ten 
 to fifteen semilunar projections, which not unfrequently have 
 a spiral form, resembling the thread of a screw. 
 
 The hepatic duct, Fig. 173, /, is formed by the union of two 
 trunks in the transverse fissure of the liver. It is about an 
 inch and a half in length. 
 
 The ductus choledochus, Fig. 173,/, is formed by the cystic 
 and the hepatic ducts. It is about two inches and a half 
 long. It is lined by a mucous membrane, which is continu- 
 ous on the one hand with the mucous membrane of the 
 duodenum, and on the other with that of the cystic duct 
 and the gall-bladder, and that of the hepatic duct and its 
 numerous subdivisions in the liver. The fibrous layer of 
 these ducts is regarded by some as being composed of the 
 
404 OF THE ABDOMEN. 
 
 non-striated muscular tissue. These ducts are partly covered 
 by peritoneum. 
 
 The gall-bladder is supplied with blood by the cystic 
 branch of the hepatic artery, Fig. 155, h, and with nerves 
 by offshoots from the hepatic plexus. 
 
 DISSECTION OF THE PANCREAS. 
 
 The pancreas, Fig. 173 (A, t, i\ is analogous to the salivary 
 glands. It is from six to seven inches in length, and about 
 three-fourths of an inch thick. Its breadth varies, its right 
 extremity or the head being much broader than its left, which 
 is called the tail. It has no proper fibrous capsule. In 
 structure, it is similar to the parotid gland. It is composed 
 of lobules, which are connected together by areolar tissue. 
 
 The pancreatic duct, Fig. 173 (e), extends the whole length 
 
 Fig. 173. 
 
 In this figure, which is altered from Tiedemann, the liver and stomach are turned 
 up, to show the duodenum, the pancreas, and the spleen. I. The under surface of 
 the liver, g. Gall-bladder. /. The common bile-duct, formed by the union of a 
 duct from the gall-bladder, called the cystic duct, and of the hepatic duct coming 
 from the liver, o. The cardiac end of the stomach, where the oesophagus enters. 
 . Under surface of the stomach, p. Pyloric end of stomach, d. Duodenum, h. 
 Head of pancreas; t, tail; and i, body of that gland. The substance of the pan- 
 creas is removed in front, to show the pancreatic duct (<?) and its branches, r. The 
 spleen, v. The hilura, at which the bloodvessels enter, c, c. Crura of diaphragm. 
 n. Superior mesenteric artery. . Aorta. 
 
DISSECTION OF THE SPLEEN. 405 
 
 of the pancreas. It lias a very white appearance when ex- 
 posed in the substance of the gland. Its parietes are thin like 
 those of the excretory duct of the submaxillary gland. The 
 branches by which it is formed join it nearly at right angles. 
 It is situated a little nearer to the anterior than to the poste- 
 rior surface of the pancreas, and nearer to the lower than to 
 the upper border. Unlike other excretory ducts, it terminates 
 almost immediately after leaving the gland. Sometimes 
 there are two ducts, which may or may not open separately 
 into the duodenum. 
 
 The lesser pancreas is merely the lower portion of the head. 
 "When there are two ducts, it is in this part of the gland that 
 the second one is found. 
 
 The vessels and nerves of the pancreas have been described 
 with the gland in situ. 
 
 DISSECTION OF THE SPLEEN. 
 
 The spleen, Fig. 173, r, occupies the deep part of the left 
 hypochondrium. It has an oval form, being flattened and 
 somewhat excavated on its inner side. It varies greatly in size. 
 It has a deep red or purple color, especially when cut into. 
 Its structure possesses but little firmness, and is easily broken 
 up by pressure. It may be lacerated by blows on the exter- 
 nal surface of the left hypochondriac region. 
 
 It presents a convex surface which looks towards the dia- 
 phragm and lower ribs, and a flat, slightly concave one, which 
 is in apposition with the left extremity of the stomach. Its 
 upper extremity is larger and more rounded than the infe- 
 rior, and its posterior border is thicker than the anterior. 
 
 A fissure, or hilum, Fig. 173, v, is observed on its flat sur- 
 face, being nearer to the posterior than to the anterior bor- 
 der. This fissure is occupied by the vessels and nerves of 
 the gland. 
 
 The spleen has, besides the peritoneal, a proper fibrous co- 
 vering, which not only invests the entire organ, but sends pro- 
 longations into every part of it, which, by interlacing, form 
 a perfect network. It is also reflected in from the hilum 
 around the vessels so as to form for them sheaths. It is 
 elastic, quite strong, and may be said to form the framework 
 of the organ. The cellular arrangement formed by this struc- 
 
406 OF THE ABDOMEN. 
 
 ture may be very well seen in a section of the spleen after 
 repeatedly washing and squeezing it until the red pulpy 
 substance, contained in the cells or interstices, has been re- 
 moved. It will be observed that the processes sent in from 
 the internal surface of the capsule are connected to the ex- 
 ternal surface of the sheaths of the vessels. The peritoneum 
 adheres closely to the fibrous capsule. 
 
 The interstices are filled with a red pulpy granular sub- 
 stance. This, when exposed to the air, assumes a bright red 
 color. Small vesicular bodies have been noticed in the 
 granular substance. 
 
 The spleen is an exceedingly vascular organ, and its size 
 depends much on the quantity of blood which it contains. 
 It has no excretory duct. Sometimes one or more small 
 bodies are found in the neighborhood of the spleen, which 
 resemble it in color and structure. 
 
 DISSECTION OF THE KIDNEYS. 
 
 These are two organs for the secretion of the urine, situated, 
 one in each lumbar region, Fig. 177 (i, i). They are some- 
 times connected across the spine so as to form what is called 
 the horse-shoe kidney. Sometimes one is entirely absent. 
 They are usually smaller in the female than in the male. 
 They are about four inches in length, two in breadth, and 
 one in thickness. In shape they resemble the kidney bean. 
 Their color is a deep brown-red. 
 
 Each kidney, Fig. 174, presents an anterior and posterior 
 surface, an upper and a lower extremity, and an outer and 
 inner border. The anterior surface is more convex than the 
 posterior, and the upper extremity is broader and thicker 
 than the lower. The external border is convex, while the 
 internal is concave and marked by quite a deep fissure or 
 hilum, which contains the renal vessels, nerves, and excretory 
 duct. The excretory duct is usually situated in the lower 
 and posterior part of the fissure or hilum, while the veins 
 are placed in the front part, with the arteries immediately 
 behind them. 
 
 The kidney has a proper fibrous capsule which invests the 
 entire organ, and sends into its substance fine delicate pro- 
 
DISSECTION OF THE KIDNEYS. 
 
 407 
 
 Fig. 174. 
 
 cesses which, are easily broken. It also joins the fibrous 
 layer of the ureter, and is prolonged internally along with 
 the vessels, as far as the apices or 
 papillae,. It requires but little force 
 to detach this membrane from the 
 substance of the kidney. 
 
 In dissecting the kidney, the student 
 should, in the first place, carefully re- 
 move the areolar tissue and fat from 
 the hilum, so as to obtain a distinct 
 view of the vessels and the ureter, 
 Fig. 174 (7, s, n). Having done 
 this, the ureter should be slit up on 
 one side, cutting away at the same 
 time a portion of the kidney. That 
 part of the ureter situated in the hilum 
 is named its pelvis, Fig. 175 (e). There 
 will be observed opening into the 
 pelvis three apertures, sometimes only 
 two ; these are called the infundibula, 
 Fig. 175 (s, s, 5 ). If one of these now 
 be laid open, a cavity will be seen 
 with several eminences or papillae 
 projecting into it. The cup-shaped 
 depression which is observed sur- 
 rounding each papilla is called the 
 calix. Sometimes two papillae are 
 found projecting into a single calix. 
 Small openings may be noticed on 
 each papilla, which are the mouths of 
 uriniferous tubes, and if the kidney 
 be pressed between the thumb and 
 finger, urine may frequently be seen escaping from them. 
 
 Each papilla is the apex of a conical-shaped portion, Fig. 
 175 (3, s) of the kidney, which is composed of a great num- 
 ber of straight tubes. If the kidney be divided through one 
 of the apices, the outlines of the cone to which the apex 
 belongs will be distinctly seen, having a striated appearance, 
 with its base imbedded in a different kind of structure. The 
 "base of each cone is rounded off, and reaches to within about two 
 lines of the external surface of the kidney. There are from 
 
 A TIEW OF THE'BJGHT KID- 
 NEY AND ITS SUPRA-RENAL 
 CAPSULE. 1. Anterior face 
 of the kidney. 2. External 
 or convex edge. 3. Its inter- 
 nal edge. 4. Hilum. 5. In- 
 ferior extremity of the kid- 
 ney. 6. Pelvis of the ureter. 
 7. Ureter. 8, 9. Superior and 
 inferior branches of the emul- 
 gent artery. 10, 11, 12. The 
 three branches of the emul- 
 gent vein. 13. Supra-renal 
 capsule. 14. Its superior 
 edge. 15. Its external edge. 
 
 16. Its internal extremity. 
 
 17. The fissure on the ante- 
 rior face of the capsule. 
 
408 
 
 OF THE ABDOMEN. 
 
 Fig. 175. 
 
 ten to eighteen of these cones, forming about one-fourth part 
 of the kidney. Each one is separate and distinct from the 
 rest. They constitute what is called the medullary portions, 
 while the remaining three-fourths is 
 named the cortical or vascular sub- 
 stance, Fig. 175 (2). The urine is 
 secreted in the latter, which is much 
 more vascular than the former, as it 
 requires blood not only for nourish- 
 ment but to supply the elements of 
 which the urine is formed. It is less 
 firm and more easily broken up than 
 the medullary substance, and is 
 usually of a brighter red color. 
 
 When the two substances are ex- 
 amined with the microscope, they are 
 both found to contain tubes. These 
 commence, for the most part, by 
 closed but dilated extremities in the 
 cortical substance. They are at first 
 very tortuous, but as they proceed to 
 enter the base of a cone, they assume a 
 straight direction. They are known 
 in the cortical substance as the con- 
 voluted tubes of Ferrein, and in the 
 cones as the straight tubes, or the ducts 
 of Bellini. From the extent of sur- 
 face on the base of each cone, it will 
 readily be seen that the number of 
 tubes which enter it must be very 
 great, and, also, that the number, by 
 the union which is constantly taking 
 place, must be greatly diminished 
 before they reach the apex of the cone. The tubes which 
 converge to form by their junction one of the straight tubes, 
 constitute a pyramid of Ferrein. 
 
 The corpuscles of Malpighi, in the cortical substance, consist of 
 tufts of vessels contained in the dilated extremities, and in cap- 
 sular dilatations on the sides of the tubes of Ferrein. Each cap- 
 sule is perforated by an afferent and an efferent vessel. The for- 
 mer is an artery, and the latter a vein. After the vein leaves the 
 
 A SECTION OP THE KlDNEY, 
 SURMOUNTED BY THE SuPRA- 
 KENAL CAPSULE ; THE SWEL- 
 LINGS ON THE SURFACE MARK 
 
 THE ORIGINAL CONSTITUTION 
 OF THE ORGAN OF DISTINCT 
 LOBES. 1. The supra-renal 
 capsule. 2. The vascular or 
 cortical portion of the kidney. 
 3, 3. Its tubular portion, con- 
 sisting of cones. 4, 4. Two 
 of the papillae projecting into 
 their corresponding calices. 
 5, 5, 5. The three infundibula; 
 the middle Sis situated in the 
 mouth of a calyx. 6. The 
 pelvis. 7. The ureter. 
 
DISSECTION OF SUPRA-EENAL CAPSULE. 
 
 409 
 
 Fig. 176. 
 
 capsule it forms a plexus around the tube, and then termi- 
 nates in a branch of the renal vein. 
 
 The URETERS convey the urine from the kidneys to the 
 bladder. They are from sixteen to eighteen inches in length. 
 Below its pelvis each one is about 
 the size of a goose-quill. The man- 
 ner in which it is formed in the 
 hilum by the calices, the infundibula, 
 and the pelvis, has been noticed in 
 the dissection of the kidney. Its walls 
 consist of two layers, a. fibrous and a 
 mucous. The fibrous layer is said to 
 contain muscular fibres, and is very 
 dilatable. The mucous membrane 
 is continuous above with the lining 
 membrane of the uriniferous tubes, 
 and below with that of the bladder. 
 The manner in which the ureter per- 
 forates the coats of the bladder will 
 be noticed in the dissection of that 
 organ. 
 
 The SUPRA-EENAL CAPSULE, Fig. 
 175 (i), is a small body of a crescen- 
 tic form, situated on the upper end 
 of each kidney. The one on the 
 right side is placed between the kid- 
 ney and the liver, resting on the dia- 
 phragm, and having the vena cava 
 and the duodenum in* front of it. 
 The left one also rests on the dia- 
 phragm, and has the spleen and pan- 
 creas" above and in front of it. 
 They are moulded on the upper 
 
 extremities of the kidneys, to which they are attached by 
 loose areolar tissue. Without some care they might be 
 readily confounded with the fat which surrounds them. 
 
 They are yellowish externally, and when cut into pre- 
 sent a striated lamina or cortical substance of the same 
 color, and a dark- colored medullary substance, of a much 
 softer consistence. Occasionally they are found to contain a 
 small cavity in the centre. They have no excretory ducts, 
 
 PLAN OP THE RENAL CIRCU- 
 LATION; COPIED FROM MR. 
 BOWMAN'S PAPER. a. A 
 branch of the renal artery 
 giving off several Malpighian 
 twigs. 1. An afferent twig to 
 the capillary tuft contained in 
 the Malpighian body, m; from 
 the Malpighian body the uri- 
 niferous tube is seen taking 
 its tortuous course to t. 2, 2. 
 Efferent veins; that which 
 proceeds from the Malpighian 
 body is seen to bo smaller 
 than the corresponding artery. 
 p, p. The capillary venous 
 plexus, ramifying upon the 
 uriniferous tube. This plexus 
 receives its blood from the 
 efferent veins, 2, 2, and trans- 
 mits it to the branch of the 
 renal vein, v. 
 
410 OF THE ABDOMEN. 
 
 and their use is not known. They are usually classed with 
 the thymus and thyroid bodies, and are supposed to perform 
 some function connected with foetal life. In the foetus they 
 are nearly as large as the kidneys. They are well supplied 
 with bloodvessels. 
 
 The abdominal viscera having been removed and examined, 
 the student may now proceed to dissect the vena cava and 
 the aorta, with such of their branches as have not already 
 been noticed. The thoracic duct, the sympathetic cord, the 
 branches of the lumbar plexus of nerves, and some of the 
 deep muscles will also be included in this dissection. 
 
 The AORTA, Fig. 177(7), will be seen entering the cavity 
 of the abdomen between the crura of the diaphragm, where it 
 rests on the b.odies of the last two dorsal vertebrae. It ex- 
 tends down to the fourth lumbar vertebra, where it divides into 
 the common iliacs. It is placed somewhat on the left side of 
 the bodies of the vertebrae over which it passes. The parts 
 placed in front of it have been, for the most part, removed, 
 or have already been examined. They are, the liver, the 
 stomach, the pancreas, the solar plexus, the vena portae, the 
 lower portion of the duodenum, the transverse colon, the 
 transverse mesocolon, the small intestines, the mesentery, the 
 aortic plexus, and the left renal vein. The vena cava ascen- 
 dens, the thoracic duct, the vena azygos, and the right semi- 
 lunar ganglion lie on its right side. On its left side are the 
 left semilunar ganglion, the left supra-renal capsule, and the 
 peritoneum, which covers the lower part of it, both in front 
 and on the left side. The left lumbar veins pass behind it. 
 
 The PHRENIC ARTERIES, Fig. 17f, and Fig. 159 (i), arise 
 from the aorta separately or in common, near the coeliac. 
 The left one passes upwards and outwards behind the oesopha- 
 gus, to ramify on the under surface of the left portion of the 
 diaphragm. The right one passes behind the vena cava, and 
 is distributed to the under surface of the right portion of the 
 diaphragm. They anastomose with each other, and with 
 branches of the internal mammary and intercostal arteries. 
 They do not always, or both of them at least, arise from the 
 aorta. 
 
 The lumbar arteries, Fig. 159 (s), and Fig. 177, consist of four 
 or five pairs. They correspond to the intercostal arteries. 
 They arise from the posterior aspect of the aorta, and pass 
 
DISSECTION OF THE DEEP VESSELS AND NEKVES. 411 
 
 outwards on the bodies of the vertebrae. The upper two on 
 each side go behind the crus of the diaphragm and the lower 
 two or three behind the psoas magnus. Each divides into an 
 abdominal and a dorsal branch. The latter, after sending a 
 branch through the intervertebral foramen to the spinal canal, 
 goes to the muscles and integument of the back. The former 
 pass behind the quadratus lumborurn, and supply branches 
 to the posterior abdominal parietes. They anastomose with 
 the intercostal, the internal circumflex ilii, and the ilio-lumbar 
 arteries. These arteries may be dissected on one side, leaving 
 the psoas magnus and the nerves to be examined on the 
 other ; or they may all be dissected at the same time. 
 
 The middle sacral artery, Fig. 159 (12), arises from the 
 posterior part of the aorta, just above its bifurcation. It is 
 
 Fig. 177. 
 
 A VIEW OP THE URINARY ORGANS IN SITU. 1, 1. The kidneys. 2, 2. The cap- 
 sulse renales. 3,3. The ureters in their course to the bladder, and their relations to 
 the bloodvessels. 4. Bladder distended with urine. 5. The rectum. 6, 6. The 
 etnulgent arteries. 7. The abdominal aorta. 8. Its division into the iliacs. 9, 9. 
 The primitive iliacs at the points where the ureters cross them. 
 
412 OF THE ABDOMEN. 
 
 directed downwards on the sacrum into the pelvis. It may 
 be traced a short distance in this stage of the dissection, but 
 it cannot be followed out in its distribution until the pelvis 
 is dissected. 
 
 The COMMON ILIAC ARTERIES, Fig. 177 (s), arise from the 
 bifurcation of the aorta, and are directed downwards and out- 
 wards to the sacro-iliac symphyses. Each is from an inch and 
 a half to two inches in length. The peritoneum and fila- 
 ments of the sympathetic nerve, and sometimes the ureter, lie 
 in front of it. The right one is usually somewhat longer 
 than the left, on account of the aorta being placed to the left 
 side. They diverge more in the female than in the male. 
 Opposite to the sacro-iliac symphysis each divides into the 
 external and internal iliac. 
 
 The EXTEENAL ILIAC ARTERY, Fig. 177, on each side is 
 directed downwards and outwards along the brim of the pelvis 
 to Poupart's ligament. It is covered by peritoneum through 
 its whole extent. The ureter generally crosses it near its 
 origin, and just above Poupart's ligament the vas deferens 
 passes over it from without inwards. The psoas magnus lies 
 at first on the outside of it, and then behind it. The exter- 
 nal iliac vein is placed on the inner side of it, except on the 
 right side where it passes under the artery near its origin. 
 Just before it passes beneath Poupart's ligament it gives off 
 the epigastric and the internal circumflex ilii arteries, which 
 have been described with the abdominal parietes. The obtu- 
 rator artery sometimes has its origin from the external iliac. 
 
 The dissection of the internal iliac artery must be post- 
 poned for the present. 
 
 The VENA CAVA ASCENDENS commences below, oppo- 
 site the last lumbar vertebra. It is formed by the union 
 of the common iliac veins. It ascends, on the right side 
 of the aorta, to the cordiform tendon of the diaphragm, 
 which it perforates, to join the right auricle of the heart. 
 In its course it receives the lumbar, the right spermatic 
 or ovarian, the renal, the supra-renal, the phrenic, and the 
 hepatic veins. The lumbar and the phrenic veins accom- 
 pany their corresponding arteries, and require no particular 
 description. The other veins have been noticed. The vena 
 cava has no valves. The external iliac veins were observed 
 in the dissection of their corresponding arteries. 
 
DISSECTION OF THE DEEP VESSELS AND NEKYES. 413 
 
 The COMMON ILIAC YEINS correspond to the common iliac 
 arteries. The left one is longer and more oblique than the 
 right. It lies at first on the inner side of the left common 
 iliac artery, and then passes under the right common iliac, to 
 join the right common iliac vein, which is placed on the 
 outer side of its accompanying artery. The middle sacral 
 vein opens into the left common iliac. The common iliac veins 
 are formed by the junction of the external and internal iliacs. 
 
 The CORD AND THE LUMBAR GANGLIA of the sympathetic 
 nerve, Fig. 142 (i 7), are situated on the bodies of the lumbar 
 vertebrae. There are usually three or four ganglia on each 
 side. The cord enters the abdomen on each side beneath 
 the inner arch of the diaphragm, or the true ligamentum 
 arcuatum, continues down along the internal border of the 
 psoas magnus muscle, and descends into the pelvis beneath 
 the common iliac artery. From the ganglia external and 
 internal branches are given off. The external branches pass 
 beneath the psoas muscle, and join the lumbar nerves. The 
 internal are directed inwards, and form, with filaments from 
 the solar plexus, the aortic plexus. Other branches go to 
 join the plexuses which supply the viscera. 
 
 The aortic plexus terminates in filaments which accompany 
 the iliac arteries, and in others which join the hypogastric 
 plexus in front of the sacrum. 
 
 The hypogastric plexus is formed by filaments from the 
 aortic plexus, and from the lumbar and sacral ganglia. Those 
 from the lumbar ganglia reach it by passing over the com- 
 mon iliac arteries. It divides into other plexuses which 
 accompany the arteries that go to the pelvic viscera. 
 
 The LUMBAR NERVES, Fig. 178, consist of five pairs. 
 They divide, after leaving the intervertebral foramina, into 
 anterior and posterior branches. The latter are distributed 
 to the muscles and the integument of the back. The anterior 
 branches are much the largest. They enter the psoas muscle, 
 where they divide and unite again with each other, so as to 
 form the lumbar plexus. The first one is connected to the 
 last dorsal, and the last two to the sacral nerves. 
 
 The LUMBAR PLEXUS, Fig. 178 (i), is larger below than 
 above. It is placed at the sides of the lumbar vertebrae, and 
 in the posterior part of the psoas muscle. It gives off the 
 
 35* 
 
414 
 
 OF THE ABDOMEN. 
 
 following nerves: The superior musculo-cutaneous or ilio- 
 scrotal, the middle musculo-cutaneous, the inferior musculo- 
 cutaneous or external cutaneous, the genito-crural, the anterior 
 crural, and the obturator. The superior and middle musculo- 
 cutaneous have been described with the abdominal parietes. 
 
 The INFERIOR MUSCULO-CUTANEOUS, or EXTERNAL CUTA- 
 NEOUS BKANCH, Fig. 178 (4), usually arises from the second 
 lumbar nerve, leaves the psoas muscle, and passes over the 
 iliacus internus to Poupart's ligament, near the anterior supe- 
 rior spinous process of the ilium. It goes under the ligament 
 and supplies the integument on the outer part of the thigh. 
 It is bound down by fascia in the iliac fossa. 
 
 The GENITO-CRURAL NERVE, Fig. 178 (9), arises from the 
 
 Fig. 178. 
 
 A VIEW OF THE LUMBAR AND SACRAL PLEXUSES AND THE BRANCHES OP THE 
 FORMER. 1. The lumbar plexus. 2. The sacral plexus. 3,3. Superior and middle 
 musculo-cutaneous nerves. 4. Inferior nausculo-cutaneous nerve. 5, 6, 7. Cutane- 
 ous branches from 8. The anterior crural nerve. 9. The genito-crural nerve. 10, 
 10. The lower termination of the great sympathetic. 1]. The iliacus internus 
 muscle. 12. The three broad muscles of the abdomen. 13. The psoas magnus 
 muscle. 14. The bodies of the lumbar vertebras. 15. The quadratus lumborum 
 muscle. 16. The diaphragm. 17. The sartorius. 
 
DISSECTION OF THE KECEPTACULUM CHYLI. 415 
 
 second and third lumbar, pierces the psoas muscle, and des- 
 cends on its anterior surface, to divide into its genital and 
 crural branches. The division may take place in the muscle. 
 The genital branch enters the inguinal canal, and joins the 
 spermatic cord, but does not form a part of it. It is dis- 
 tributed to the scrotum, in the male, or the external labia 
 in the female. The crural branch passes through the crural 
 ring, and is lost on the anterior part of the thigh. 
 
 The ANTERIOR CRURAL NERVE, Fig. 178 (s), arises prin- 
 cipally from the third and fourth lumbar. It pierces the 
 psoas muscle, and gets in the groove between it and the 
 iliacus internus. It passes beneath Poupart's ligament, about 
 half an inch to the outer side of the femoral artery. It sends 
 small branches to the psoas and iliacus internus muscles. 
 
 The OBTURATOR NERVE arises from the third and fourth 
 lumbar, and passes downwards on the inner side of the 
 psoas muscle, and behind the external iliac vessels to the 
 opening in the upper part of the obturator ligament. It 
 is distributed to the muscles and integument on the inner 
 part of the thigh. It also sends filaments to the hip-joint. 
 Sometimes there is an accessory obturator nerve which arises 
 from the third and fourth lumbar, and descends on the inner 
 side of the psoas to the pubic bone, over which it passes to 
 the thigh. It sends filaments to the pectineus and adductor 
 brevis, to the hip -joint, and others to unite with the obturator 
 nerve. 
 
 'A fasciculus from the fourth and the whole of the fifth 
 lumbar nerve descends into the pelvis to join the sacral 
 plexus and to form the superior gluteal nerve. It is named 
 the lumbo-sacral nerve. 
 
 The KECEPTACULUM CHYLI, Fig. 141 (12), or the com- 
 mencement of the thoracic duct, should be sought by the 
 student. It is placed in front of the second lumbar vertebra, 
 and between the right crus of the diaphragm and the aorta. 
 The vena azygos is situated on the right side of it. It re- 
 quires a little care to distinguish it from the areolar tissue 
 around it. It is formed by the union of three or four lym- 
 phatic trunks. 
 
 The ILIAC FASCIA should be examined before the iliacus 
 and psoas muscles are dissected. It is attached to the outer 
 
416 OF THE ABDOMEN. 
 
 two-thirds of Poupart's ligament, where it is continuous 
 with the fascia transversalis, to the whole of the inner border 
 of the crest of the ilium, to the ligamentum arcuatum ex- 
 ternum, to the bodies of the lumbar vertebrae, and to the brim 
 of the pelvis. The lower part is thicker and more aponeuro- 
 tic than the upper and inner part. It covers the psoas and 
 iliacus internus muscles. The external iliac artery and vein 
 lie in front of it. Where these vessels pass beneath Pou- 
 part's ligament, a process of the iliac fascia is prolonged down 
 behind them, which, joined to a similar prolongation of the 
 fascia transversalis in front of the vessels, forms a funnel- 
 shaped sheath around them. This will be noticed more par- 
 ticularly in the dissection of the parts concerned in femoral 
 hernia. 
 
 It will be observed, from the attachment of the iliac fascia, 
 that when pus collects beneath it, it will have a tendency to 
 follow the psoas and iliacus muscles to the upper and anterior 
 part of the thigh. 
 
 The PSOAS MAGNUS, Fig. 178 (i 3), arises from the margins 
 of the bodies of the lower two dorsal and the upper four lum- 
 bar vertebra?, from the intervertebral substance, from the 
 ligamentous bands which arch over the grooves on the sides 
 of the bodies of the vertebras, and from the bases of the trans- 
 verse processes. The fibres proceed downwards and some- 
 what outwards along the brim of the pelvis, beneath Pou- 
 part's ligament, and end in a tendon which passes backwards 
 and inwards over the capsular ligament of the hip-joint, and 
 is inserted into the posterior part of the small trochanter. A 
 bursa is placed between its tendon and the pubic bone and the 
 capsular ligament. There is also a small bursa between it 
 and the trochanter. The lumbar arteries and the nerves of 
 communication between the lumbar and the sympathetic pass 
 in the grooves on the bodies of the vertebras, beneath the 
 tendinous arches from which this muscle in part arises. The 
 action of the psoas is to flex the thigh on the pelvis, or the 
 body on the thigh. From the position of the trochanter 
 minor this muscle rotates the thigh outwards before flexing 
 it on the body. 
 
 The PSOAS PAR v us is frequently wanting. When present, 
 it is situated mainly in front of the psoas magnus. It arises 
 from the bodies of the last dorsal and the first lumbar ver- 
 
DISSECTION OF THE DIAPHKAGM. 417 
 
 tebrse, and from the intervertebral substance between them. 
 The fibres pass downwards, and terminate in a thin flat ten- 
 don, which is inserted into the brim of the pelvis and into 
 the iliac fascia. As it descends it crosses the psoas magmis 
 from without inwards. Its action is to render the iliac fascia 
 tense, and, through it, Poupart's ligament. It may also assist 
 in flexing the pelvis on the spine. 
 
 The ILIACUS INTEENUS, Fig. 178 (i i), arises from the whole 
 of the iliac fossa, from the ilio-lumbar ligament, from the an- 
 terior spinous processes of the ilium and the notch between 
 them, and from the capsular ligament of the hip-joint. The 
 fibres converge and pass downwards and inwards to end in 
 the tendon of the psoas magnus with which it is inserted into 
 the trochanter minor. A portion of its fibres are inserted 
 directly into the shaft of the femur just below the trochanter. 
 Its action is similar to that of the psoas magnus. These mus- 
 cles are concerned in walking; as, in raising and moving the 
 lower extremity forwards. When they act on both sides and 
 the thighs are fixed, they bend the body forwards. 
 
 The DIAPHRAGM, Fig. 179, forms a muscular septum be- 
 tween the thoracic and abdominal cavities. Its upper sur- 
 face is covered by the pleurae and the pericardium, and is 
 in relation with the thoracic viscera; its lower surface is 
 principally covered by the peritoneum, and is in relation with 
 the viscera of the abdomen. The peritoneum is easily re- 
 moved by dissecting and peeling it off before the cavity of 
 the thorax is opened, as the muscle is then tense. It is usu- 
 ally described as consisting of a greater and a lesser muscle, 
 which are connected by a central tendon. 
 
 The greater muscle, Fig. 179 (i, 2, s), forms the anterior 
 and lateral portions ; the lesser muscle, Fig. 179 (s, i o), forms 
 the posterior part. The first arises from the ensiform carti- 
 lage, the last true and all the false ribs, and from the liga- 
 menta arcuata, externum and internum. Its origin from the 
 ensiform cartilage consists of one or two fasciculi, with a 
 small triangular space on each side, in which the anterior 
 mediastinal space is separated from the abdomen only by 
 peritoneum. Viscera of the abdomen may be forced through 
 these spaces into the thorax, producing diaphragmatic hernia 
 or pus may escape from the mediastinum through them into 
 
418 OF THE ABDOMEN. 
 
 the abdomen. Its costal attachments form indigitations with 
 the transversalis muscles. 
 
 Fig. 179. 
 
 THE UNDER OR ABDOMINAL SIDE OF THE DIAPHRAGM.!, 2, 3. The greater 
 muscle ; the figure 1 rests upon the central leaflefr*of the tendinous centre ; the 
 number 2 on the left or smallest leaflet ; and number 3 on the right leaflet. 4. 
 The thin fasciculus which arises from the ensiform cartilage ; a small triangular 
 space is left on either side of this fasciculus, which is closed only by the serous 
 membranes of the abdomen and chest. 5. The ligamentum arcuatum externum of 
 the left side. 6. The ligamentum arcuatum internum. 7. A small arched opening 
 occasionally found, through which the lesser splanchnic nerve passes. 8. The right 
 or larger tendon of the lesser muscle; a muscular fasciculus from this tendon curves 
 to the left side of the greater muscle between the oesophageal and aortic openings. 
 9. The fourth lumbar vertebra. 10. The left or shorter tendon of the lesser mus- 
 cle. 11. The aortic opening occupied by the aorta, which is cut short off. 12. 
 A portion of the oesophagus issuing through the oesophageal opening. 13. The 
 opening for the inferior vena cava, in the tendinous centre of the diaphragm. 14. 
 The psoas magnus muscle passing beneath the ligamentum arcuatum internum; 
 it has been removed on the opposite side to show the arch more distinctly. 15. 
 The quadratus lutnborum passing beneath the ligamentum arcuatum externum ; 
 this muscle has also been removed on the left side. 
 
 The fibres converge from this extended origin, and are in- 
 serted into the anterior and lateral borders of the central 
 tendon. 
 
 The lesser muscle arises, tendinous, on the right side from the 
 bodies of the upper three or four lumbar vertebrae, and from 
 their intervertebral substance ; and on the left side from the 
 
DISSECTION OF THE DIAPHRAGM. 419 
 
 first two or three vertebras. These portions are named the 
 crura, or pillars of the diaphragm. They pass upwards and 
 forwards, and at a short distance in front of the last dorsal 
 vertebra are united by a fibrous band, which forms an arch 
 over the aortic opening. Above this point they become 
 muscular, and by a decussation of their inner fasciculi, 
 partly form the oesophageal opening, and separate it from 
 the aortic. They spread out, and finally end in the posterior 
 part of the central tendon. 
 
 The central or cordiform tendon is composed of three parts, 
 called leaflets, or alee, Fig. 179 (i, 2, 3). The middle and an- 
 terior one is usually the largest. It corresponds to the peri- 
 cardium. The left one is the smallest, and is below the left 
 lung. The fibres of this tendon interlace with each other, 
 and are also crossed in different directions by accessory 
 fibres. 
 
 There are three principal foramina in the diaphragm. 
 
 The hiatus aorticus, Fig. 179 (i i), is situated in front of the 
 body of the last dorsal vertebra, and between the crura. 
 It transmits the aorta, and sometimes one of the great 
 splanchnic nerves. 
 
 The oesophageal opening, Fig. 179 (12), is placed directly 
 behind the cordiform tendon, which sometimes forms a part 
 of its anterior boundary. It is to the left, and in front of 
 the aortic opening. The decussating fasciculi of the crura 
 form its posterior and lateral boundaries. It has been sup- 
 posed that these fasciculi might act as a sort of sphincter 
 muscle to the oesophagus, as it passes through this opening. 
 The oesophagus and the pneumogastric nerves pass through 
 it. The aortic and oesophageal foramina lead from the cavity 
 of the abdomen into the posterior mediastinum. 
 
 The foramen quadratum, Fig. 179 (is), is situated to the 
 right side of the median line, and considerably anterior to 
 either of the others. It is placed in the posterior part of 
 the right leaflet, and is wholly surrounded by tendinous 
 fibres ; thus the vena cava is not liable to be compressed by 
 the action of the diaphragm. It transmits the ascending 
 cava and a few filaments of the phrenic nerve. 
 
 The sympathetic, and the greater and lesser splanchnic 
 nerves, and also the left azygos vein, pass through small 
 foramina in the diaphragm. 
 
 The diaphragm is a muscle of inspiration. When it acts, 
 
420 OF THE PELVIS. 
 
 the lateral muscular portions descend, and the fibres assume 
 nearly a horizontal direction. It also assists the muscles of 
 the abdomen in compressing the abdominal viscera, &c. The 
 cordiform tendon is subject to but very little movement. 
 
 The LIGAMENTUM ARCUATUM EXTERNTJM, Fig. 179 (5), 
 extends from the transverse process of the first lumbar ver- 
 tebra to the last rib. It forms a fibrous arch over the 
 quadratus lumborum muscle. It is the upper border of the 
 anterior lamina of the fascia lumborum. 
 
 The LIGAMENTUM AKCUATUM INTEENUM, Fig. 179 (e), 
 passes from the body of the second lumbar vertebra to the 
 transverse process of the first. It forms a fibrous arch over 
 the psoas magnus and the sympathetic nerve. 
 
 SECT. III. DISSECTION OF THE PELVIC YISCEKA. 
 THE EECTUM. 
 
 The EECTUM, Fig. 167 (s), is the last portion of the ali- 
 mentary canal. It occupies the posterior part of the pelvic 
 cavity, and extends from the sigmoid flexure of the colon to 
 the anus. In an antero-posterior direction it presents only 
 a single curvature, which corresponds to that formed by the 
 sacrum and os coccygis, until it reaches the lower part of the 
 coccyx, where it is inclined a little backwards. The upper 
 part of it is directed, laterally, from a point opposite the left 
 sacro-iliac junction to the median line in the lower part of 
 the hollow of the sacrum. 
 
 It is from six to eight inches in length. It is cylindrical, 
 but not sacculated, like the colon. The upper part of it is 
 somewhat constricted, but the lower part, to within a short 
 distance of the anus, is expanded into a pouch-like dilatation, 
 below which it is again contracted. 
 
 The rectum has the same number of layers in its walls as 
 the other divisions of the intestinal canal, except the lower 
 third, which has no serous covering. The muscular coat is 
 much thicker than that of the colon or small intestine, re- 
 sembling in this respect the oesophagus. 
 
 The longitudinal fibres are not arranged in bands as they 
 are in the colon, but are distributed equally on all sides, as 
 
DISSECTION OF THE BLADDER. 421 
 
 in the small intestine. Some of them terminate in the ex- 
 ternal sphincter of the anus ; others are reflected inwards 
 and upwards around the internal sphincter, and are lost in 
 the submucous areolar tissue from half an inch to an inch 
 above the anus. 
 
 The circular fibres are collected into quite a large fasci- 
 culus at the lower end of the rectum, forming what is called 
 the internal sphincter of the anus. 
 
 The mucous membrane of the rectum presents a number of 
 large irregular folds, which are not wholly obliterated when 
 the bowel is distended. At the lower end of the bowel there 
 are several small longitudinal folds, between which depres- 
 sions exist, and in which foreign substances are sometimes 
 lodged. The mucous membrane in the lower part of the 
 rectum is very loosely connected to the muscular layer. 
 Hence prolapsus of it sometimes occurs. 
 
 'The arteries of the rectum are the superior, the middle, 
 and the inferior hemorrhoidal. The superior are branches of 
 the inferior mesenteric; the middle, of the internal iliac; and 
 the inferior, of the internal pudic. The rectum is more vas- 
 cular than any other portion of the large intestine. 
 
 The veins are named the superior, middle, and inferior 
 hemorrhoidal. A plexus of veins is found beneath the mu- 
 cous membrane in the lower part of the rectum, which, by 
 becoming varicose, forms hemorrhoids. This plexus com- 
 municates with the vesical plexus. The hemorrhoidal veins 
 empty partly into the inferior mesenteric, and partly into the 
 internal iliac. 
 
 The nerves of the rectum are derived from the sympathetic 
 system, and from the sacral plexus. 
 
 DISSECTION OF THE BLADDEK. 
 
 The BLADDER should be examined in situ, when distended 
 as well as when empty, in order to understand its relations 
 to the surrounding parts in both of these conditions. To 
 study its structure, it should be removed from the pelvis 
 together with the prostate gland and the penis. It varies 
 greatly in size in different individuals, and under different 
 circumstances. It is said to be larger and more globular in 
 the female than in the male. 
 36 
 
422 OF THE PELVIS. 
 
 Its parietes are composed of a serous, a muscular, a cellu- 
 lar, and a mucous layer. 
 
 The SEEOUS LAYER is found only on the upper, posterior, 
 and lateral portions. The anterior surface has no serous in- 
 vestment, nor have the sides anteriorly ; and the same is true 
 of the lower part posteriorly, especially when the bladder is 
 distended. The serous layer is loosely connected to the one 
 beneath it by areolar tissue. 
 
 The MUSCULAR LAYER, Fig. 186, consists of three sets 
 of fibres or fasciculi, a longitudinal, a circular, and a reticu- 
 lar. To examine the muscular structure of the bladder, it 
 should be distended with air or some suitable material, as 
 hair or tow. 
 
 The longitudinal fibres are placed on the outside. They 
 are spread out over the entire organ, and terminate below 
 at the neck of the bladder; some of them are inserted 
 into the cervix, others enter the substance of the prostate 
 gland, and a few are attached to the anterior ligament of the 
 bladder and through it to the pubic bone. 
 
 The circular fibres are thinly scattered over the body of 
 the bladder, but increase in number towards the cervix, where 
 they form what has been regarded by some as the sphincter 
 vesicce. 
 
 The reticular fibres are very irregular in their distribution. 
 They cross each other in different directions, and give to the 
 interior of the bladder a reticulated appearance. Sometimes 
 these fasciculi become so large that quite deep crevices are 
 found between them, into which the mucous membrane is 
 reflected, forming pouches in which calculi are sometimes 
 lodged. "When these pouches exist, the bladder is said to be 
 sacculated. 
 
 The CELLULAR LAYER is placed between the muscular and 
 mucous, and requires no particular description. 
 
 To examine the Mucous LAYER, Fig. 180, and the in- 
 ternal appearance of the bladder, it should be laid open along 
 the median line in front. The mucous membrane is thin, 
 soft, and of a pale color, and presents numerous folds, most 
 of which are transverse. These rugge, however, disappear 
 when the bladder is filled. Mucous follicles may be seen, 
 especially in the neighborhood of the cervix. The orifices 
 of the ureters and 'of the urethra, with the triangular space 
 
DISSECTION OF THE BLADDER. 
 
 423 
 
 Fig. 180. 
 
 called the trigone, will be observed in the lower and posterior 
 part of the bladder. 
 
 The trigone, or vesical triangle, 
 Fig. 180 (7), is the small space 
 between the three orifices of the 
 bladder. The rugae, which are 
 seen in other parts of the blad- 
 der, are here absent, the surface 
 being smooth, with the excep- 
 tion of some fine strias, which 
 are directed towards the orifice 
 of the urethra. 
 
 The orifices of the ureters, Fig. 
 180 (s, 3), which appear like 
 small slits in the mucous mem- 
 brane, are situated at the pos- 
 terior angles of the trigone. The 
 distance between them varies ac- 
 cording as the bladder has been 
 contracted or distended. A probe 
 should be passed through the 
 orifice of one of the ureters, to 
 show the oblique manner in 
 which it perforates the coats of 
 the bladder. It will be found to 
 traverse three-fourths of an inch 
 or more of the cellular layer after 
 perforating the muscular coat. 
 This arrangement prevents the 
 contents of the bladder, even 
 when it is filled with air, from 
 passing into the ureters. 
 
 THE BLADDER AND URETHRA OP A MAN LAID OPEN IN ITS WHOLE LENGTH. 1, 1. 
 The bladder cut open by a crucial incision, and the four flaps separated. 2, 2. The 
 ureters. 3, 3. Their vesical orifices. 4. Uvula vesicge. The triangle formed by the 
 points at 3, 3, 4, is the vesical triangle. 5. Superior fundus'of the bladder. 6. Bas 
 fond of the bladder. 7. The smooth centre of the vesical triangle. 8. Verumon- 
 tanum, or caput gallinaginis. 9. Orifice of the ductus ejaculatorius. 10. Depression 
 near the verumontanum. 11. Ducts from the prostate gland. 12,13. Lateral lobes 
 of the prostate gland. 14. Prostatic portion of the urethra ; just above is the neck 
 of the bladder. 15. Membranous portion of the urethra. 16. One of Cowper's 
 glands. 17. The orifices of their excretory ducts. 18, 18. Section of the bulb of 
 the urethra with its erectile tissue. 19, 19. Cut edges of the corpora cavernosa. 
 20. Cut edges of the glans penis. 21. Prepuce dissected off. 22. Internal surface 
 of the urethra laid open. 23, 23. Outer surfaces of corpora cavernosa. 24,25. Ac- 
 celerator urine muscles. 26, 27. Erector penis muscles. 28, 29. Vasa deferentia. 
 
424 OF THE PELVIS. 
 
 The uvula vesicce, Fig. 180 (4), is a slight elevation seen at 
 the apex of the trigone, and near the orifice of the urethra. 
 It is formed by a thickening of the submucous areolar tissue, 
 and corresponds to the third lobe of the prostate gland. 
 
 If the mucous membrane of the trigone be dissected off, a 
 strong fasciculus of muscular fibres will be found situated 
 at its base, extending between the orifices of the ureters ; 
 and also a fasciculus going from the orifice of each of the 
 ureters to the uvula. The last have been called the muscles of 
 the ureters , or the muscles of Bell, as they were described by 
 him. A layer of dense, white fibrous tissue is found imme- 
 diately beneath the mucous membrane in the trigone. It is 
 on account of this structure, to which the mucous membrane 
 is closely adherent, that no ruga3 or folds are found in this 
 part of the bladder. 
 
 The Neck of the bladder, although its limits are not de- 
 fined by any natural lines of demarcation, may be considered 
 as that part which is applied to the base of the prostate gland. 
 It is surrounded above and laterally, on the outside of the 
 mucous membrane, by a fibro-muscular tissue, which is sup- 
 posed to act as a sphincter muscle. Many of the longitudinal 
 fibres of the bladder are inserted into this structure. 
 
 DISSECTION OF THE PROSTATE GLAND. 
 
 The PROSTATE GLAND, Fig. 181 (7), surrounds the neck of 
 the bladder and the upper portion of the urethra. It is of a 
 conical shape, with its base applied to the bladder. Its trans- 
 verse diameter is about an inch and a half, its antero- 
 posterior an inch and a quarter, and its vertical from three- 
 fourths of an inch to an inch. The antero-posterior diameter 
 is in the direction of the urethra. Its relations to the sur- 
 rounding parts are described with the pelvic viscera in situ. 
 The urethra passes through the upper part of it, having only 
 about one-third of the gland above it ; it varies, however, a 
 great deal in this respect. It consists of three lobes, two 
 lateral and a middle. The latter is quite small ; it is placed 
 behind and between the other two, and is partly separated 
 from them by a notch which is occupied by the common 
 ejaculatory ducts. The uvula vesicae is situated directly 
 above it. 
 
 The prostate is composed of numerous granules >, which are 
 
DISSECTION OF THE URETHRA. 425 
 
 arranged so as to form lobules. These are compressed closely 
 together, so that the gland has quite a dense, solid feel. It 
 is traversed by muscular fibres, which come from the bladder. 
 Its ducts, varying from ten to fifteen in number, open into 
 the urethra on each side of the caput gallinaginis. Small 
 calculi sometimes lodge in the mouths of these ducts. 
 
 THE URETHRA. 
 
 The URETHRA is from seven to nine or ten inches in length, 
 extending from the bladder to the end of the penis. It is 
 composed of a mucous membrane, supported by a layer of 
 areolar tissue, in which is observed longitudinal bands, sup- 
 posed by some to be muscular, and by others fibrous. It is 
 divided into three parts, each of which requires special 
 notice, not only on account of its peculiar appearance, but on 
 account of its relations to contiguous parts. The three divi- 
 sions are named the prostatic, the membranous, and the spongy. 
 In specifying the relative length of these divisions, the ure- 
 thra wi}l be supposed to be nine inches long. 
 
 The PROSTATIC PORTION, Fig. 180 (14), is an inch and a 
 quarter in length. It is shaped like a wine-cask, being larger 
 in the middle than at the extremities. At the bottom of it 
 in -the median line is a prominence named the caput gallina- 
 ginis, or verumontanum, Fig. 180 (s). On the summit of this 
 and near the middle, is the sinus pocularis, or utricle, which 
 extends a short distance downwards and backwards in the 
 direction of the common ejaculatory ducts which not unfre- 
 quently open into it. On each side of the verumontanum is 
 a depression, named the prostatic sinus, Fig. 180 (i i). The 
 ducts of the prostate gland open into these sinuses, except 
 those of the middle lobe, which open j ust behind and above 
 the verumontanum. This portion of the urethra is sur- 
 rounded by the prostate gland, and by the muscular coat of 
 the bladder, which is prolonged downwards immediately 
 around the urethra as well as into the substance of the gland. 
 
 The MEMBRANOUS PORTION, Fig. 180(i 5), and Fig. 181 (i o), 
 is about three-fourths of an inch in length. It extends from 
 the prostatic to the spongy portion. It passes through the tri- 
 angular ligament, which fixes it firmly in its position. It is 
 
 36* 
 
426 OF THE PELVIS. 
 
 covered by an erectile elastic tissue, by tlie muscles of Wil- 
 son and Guthrie, and by a layer of the deep perineal fascia. 
 The caliber of its anterior extremity is smaller than that 
 of any other part of the urethra, except the external orifice. 
 
 Fig. 181. 
 
 A LONGITUDINAL SECTION OF THE BLADDER, PROSTATE GLAND, AND PENIS, SHOW- 
 ING THE URETHRA. 1. The urachus. 2. The recto- vesical fold of peritoneum. 3. 
 The opening of the right ureter. 4. A slight ridge, formed by the muscle of the 
 ureter. 5. The commencement of the urethra : the elevation of mucous membrane 
 immediately below the number is the uvula vesicae. 6. The prostatic portion of the 
 urethra. 7. The prostate gland. 8. The isthmus, or third lobe of the prostate ; 
 immediately beneath which the ejaculatory duct is seen passing. 9. The right 
 vesicula seminalis. 10. The membranous portion of the urethra. 11. Cowper's 
 gland of the right side, with its duct. 12. The bulbous portion of the urethra. 13. 
 The fossa navicularis. 14. The corpus cavernosum. 15. The right crus penis. 
 16. Near the upper part of the corpus cavernosum, the section has fallen a little to 
 
 the left of the middle line; a portion of the septum pectiniforme is consequently 
 seen. 17. The glans penis. 18. The lower segment of the glans. 19. The meatus 
 urinarius. 20. The corpus spongiosum. 21. The bulb of the corpus spongiosum. 
 
 The SPONGY POKTION is about seven inches in length, Fig. 
 181. It presents two enlargements: the bulbous, and the 
 fossa navicularis. The former, Fig. 181 (12), is situated in 
 the lower part and near its commencement, and the latter, 
 Fig. 181 (i 3), which is a lateral dilatation, near the meatus. 
 Just in front of the bulbous portion are seen, on the lower 
 surface, the orifices of the ducts of Cowper's glands, Fig. 
 181 (i i). Crypts, or lacunce, are found distributed over the 
 whole surface. Some of these are the external orifices of 
 canals which run backwards from half an inch to an 
 inch beneath the mucous membrane. A very large one is 
 sometimes met with on the upper surface, and about three- 
 
DISSECTION OF THE PENIS. 
 
 427 
 
 quarters of an inch from the meatus ; it is named the lacuna 
 magna. A small, pointed catheter, or bougie, may enter 
 one of these lacunae, especially if it should happen to be 
 unusually large. The meatus urinarius, Fig. 181 (i 9), is the 
 external orifice of the urethra. It is a vertical slit in the 
 lower and anterior part of the glans. The spongy portion 
 of the urethra is surrounded by the corpus spongiosum, and 
 the upper part of it also by the acceleratores muscles. 
 
 The CORPUS SPONGIOSUM, Fig. 181 (20), consists of a de- 
 licate erectile tissue, which surrounds the spongy portion of 
 the urethra. It is expanded posteriorly to form the bulb, 
 and anteriorly, to form the glans penis. It is thicker below, 
 and on the sides of the urethra, than above it. It is covered 
 by a thin fibrous lamina, from the inner surface of which 
 numerous processes or trabeculas project into its substance, 
 and form there a fine network. The bulb is quite promi- 
 nent, and projects backwards to the extent of three or four 
 lines beneath the membranous part of the urethra. It is 
 covered by a fibrous lamina reflected from the triangular 
 ligament or deep perineal fascia. 
 
 The GLANS PENIS, Fig. 182, forms the head of that organ. 
 It is of a somewhat conical shape. Its structure is the same 
 as that of the corpus spongiosum. Its 
 base is oblique from above downwards and 
 forwards, and is excavated behind for the 
 reception of the anterior extremities of the 
 corpora cavernosa, over which the margin 
 of its base projects and forms the corona 
 glandis. It is much longer above than be- 
 low, where there is a slight groove for the 
 attachment of the frcenum prceputii. 
 
 The CORPORA CAVERNOSA, Fig. 181 
 (14), form the body of the penis. They 
 consist of a spongy erectile tissue, in- 
 closed in a dense white fibrous membrane. 
 They are firmly attached, posteriorly, to 
 the rami of the ischia, and the descend- 
 ing rami of the pubes. From these 
 points of attachment they are directed 
 upwards and forwards, increasing in size, 
 to a point opposite the symphysis pubis, 
 where they are joined to each other; 
 
 Fig. 182. 
 
 A VIEW OF THE GLANS 
 PENIS INJECTED. 1. 
 Portions of the corpora 
 cavernosa. 2. The pre- 
 puce turned back. 3. 
 Its fraenum. 4, 4. Glan- 
 dulae odorifera3 Tysoni. 
 5. Point of the glans pe- 
 nis. 6. Prominences of 
 the glans on each side of 
 the fraenum. 7. The fur- 
 row which separates the 
 sides of the glans. 8. 
 Corona glandis. 
 
428 
 
 OF THE PELVIS. 
 
 A SECTION OP THE CORPORA. 
 CAVERNOSA PENIS 1, 1, AND COR- 
 
 PUS SPONGIOSUM URETHRA 4. 
 
 Fig. 183. these portions of them are named 
 
 the crura, Fig. 181 (is). They 
 terminate anteriorly in a rounded 
 extremity, without any line of se- 
 paration between them. They 
 present a groove on the under sur- 
 face in the median line for the 
 lodgment of the urethra, and one 
 above, which is occupied by the 
 dorsal vessels and nerves of the 
 penis. Internally they are sepa- 
 rated by the septum pectiniforme, 
 Fig. 183 (s). This is a perfect 
 septum posteriorly, bat consists, 
 anteriorly, of fasciculi, which are 
 forme. 5. Canal of the urethra, connected above and below to the 
 
 por^ct rno^a ThSch ^as^from P ar i etes Common to the tWO bodies, 
 
 the median septum to the external resembling, as the name implies, 
 
 fibrous membrane. fa Q teet ^ Q f a com b. These fasti- 
 
 culi are loosely connected together 
 
 anteriorly by areolar tissue. From the incompleteness of this 
 septum, and the intimate connection existing between the 
 two bodies, they might be regarded as constituting but one. 
 From the inner surface of the walls of the corpora cavernosa 
 processes are sent internally, which intersect and unite with 
 each other so as to form a complete network, Fig. 183 (e). 
 The trabecular arrangement is much coarser in these bodies 
 than it is in the corpus spongiosum. The trabeculce contain 
 more or less of yellow fibrous tissue. There is very little if 
 any vascular connection between the corpora cavernosa and 
 the glans penis. 
 
 The GLANDS OF COWPER, Fig. 181 (n), are two small 
 bodies located just behind the bulb of the urethra. These 
 ducts open into the urethra anterior to the sinus of the bulb ; 
 they are about an inch in length. 
 
 The SKIN which covers the penis is very thin, extensible, 
 and free from, hair bulbs. It is connected to the parts be- 
 neath it by loose areolar tissue, which allows it to move on 
 the parts which it covers with great facility. This areolar 
 tissue contains no fat, but is very liable to be distended by 
 serous effusions. It contains, on the dorsum, posteriorly, the 
 
DISSECTION OF THE PENIS. 429 
 
 fibres which, descend from the linea alba to form the super- 
 ficial suspensory ligament of the penis. Some yellow elastic 
 fibres are usually found in this ligament. 
 
 The PKEPUCE, Fig. 182 (2), is formed by a duplicature of 
 the skin, which projects over and sometimes beyond the 
 glans penis. The reflected portion of it assumes the charac- 
 ter of a mucous membrane, and is continued from the cervix 
 over the glans to the orifice of the urethra, where it be- 
 comes continuous with the lining membrane of that canal. 
 When the prepuce covers the glans so as to confine it, it 
 forms what is called phymosis. When it becomes constricted 
 behind the corona, it forms paraphymosis. 
 
 In the cervix, or depression behind the corona, there are 
 some sebaceous glands, named the glandulce, odoriferce, Tysoni, 
 Fig. 182 ( 4 , 4 ). 
 
 The frcenum prceputii, Fig. 182 (3), consists of a triangular 
 fold of the mucous membrane, which is attached to the groove 
 in the glans just below and behind the meatus urinarius. 
 
 The arteries of the penis are derived principally from 
 the internal pudic. The corpus spongiosum is supplied 
 by the bulbous branches, which penetrate the bulb. The 
 branches which are distributed to the corpora cavernosa 
 enter the crura; they are called the arteries of the corpora 
 cavernosa. The glans, the prepuce, and the skin, are sup- 
 plied by the dorsal branches, which reach the dorsum of the 
 penis by passing between the crura and perforating the sus- 
 pensory ligament. The arteries which enter the spongy and 
 cavernous bodies divide into a great number of branches ; 
 some of which are appropriated to the nourishment of the 
 tissues, and others terminate by communicating freely with 
 the venous plexus in the intertrabecular spaces. 
 
 The veins of the penis are large ; they are divided into the 
 dorsal or superficial, and the veins of the corpora cavernosa. 
 The dorsal pass backwards beneath the symphysis pubis, and 
 between the crura, to terminate in the prostatic and vesical 
 plexuses, while those of the corpora cavernosa end in the 
 internal pudic veins. The veins which proceed from the 
 spongy structure commence by dilatations, which form plex- 
 uses in the intertrabecular spaces. 
 
 The nerves of the penis are derived mainly from the in- 
 ternal pudic. 
 
430 OF THE PELVIS. 
 
 DISSECTION OF THE TESTICLES. 
 
 The genital organs consist of the testicles, which secrete 
 the semen, and the apparatus necessary for its transmission 
 from the body ; a part of their excretory apparatus, as the 
 urethra, is common to both the genital and the urinary organs. 
 The urethra, with the penis, has already been examined. 
 Before examining the testicles, the coverings which they 
 have independently of their proper tunics should be dis- 
 sected. Being situated in the abdomen, in the early part 
 of foetal life, they obtain these investments in their descent 
 into the scrotum. If the student has become familiar with 
 the coverings of the bowel in oblique inguinal hernia, he 
 will have little or no difficulty in understanding the different 
 layers which cover the testicle. They are the following, 
 proceeding from without inwards : 
 
 The integument forms a pouch common to both testicles ; 
 it is named the scrotum. It is very thin, of a dark color, 
 more or less wrinkled, and covered with hairs. A ridge is 
 seen in the median line, called the rapM ; this is continued 
 backwards in the perineum, and forwards on the under sur- 
 face of the penis. 
 
 The dartos is placed immediately beneath the skin, with 
 which it is closely connected. It is continuous with the su- 
 perficial fascia of the groin and the perineum. It forms two 
 pouches, one for each testicle ; the septum is attached above 
 to the under surface of the penis. The dartos is composed 
 principally of areolar tissue and non-striated muscular fibres. 
 It supports the testicles, and when it contracts, necessarily 
 corrugates the skin which is adherent to it. 
 
 The intercolumnar or spermatic fascia is derived from the 
 margins of the external abdominal ring. The upper part of 
 this contains some fibres prolonged downwards from the in- 
 tercolumnar fibres. 
 
 The cremaster muscle consists in the scrotum of loops of 
 scattered fasciculi connected together by condensed areolar 
 tissue. The term cremasteric fascia has been applied to these 
 fasciculi and the connecting areolar tissue. 
 
 The fascia transversalis is prolonged around the spermatic 
 cord into the scrotum, and forms one of the coverings to the 
 testicle. 
 
DISSECTION OF THE TESTICLES. 431 
 
 The TUNICA YAGINALIS, Fig. 184(i ), was, before the descent 
 of the testicle, a portion of the peritoneum. The testicle, 
 while in the abdomen, is covered by the peritoneum in the 
 same manner as the spleen or the liver, and when it descends 
 into the scrotum carries along with it, not only the portion 
 which adheres to its proper tunic, the tunica albuginea, but 
 also a portion of the peritoneum which is attached to the 
 walls of the abdomen. Hence the tunica vaginalis presents 
 two portions, one of which is still adherent to the tunica 
 albuginea, while the other is reflected over the inner surface 
 of the pouch formed by the prolongation of the fascia trans- 
 versalis. The latter is denominated the tunica vaginalis re- 
 flexa, and the former, the tunica vaginalis testis. They are 
 analogous to the parietal and visceral portions of the pleura, 
 or of the peritoneum, and, like these membranes, form a 
 shut sac. 
 
 In studying the descent of the testicle, the student should 
 bear in mind that it was just as much covered by the perito- 
 neum, in the cavity of the abdomen, as it is by the tunica 
 vaginalis, in the scrotum, and that the latter is to it in the 
 scrotum, what the former wa& in the abdomen. The tunica 
 vaginalis should be studied with reference to the occurrence 
 of hydrocele, &c. 
 
 The TESTICLE is brought into view when the tunica vagi- 
 nalis is laid open. It is of an oval form, flattened somewhat 
 on the sides. It is about an inch and a half in length, and 
 about three-fourths of an inch in thickness, and an inch in 
 breadth. Its position in the scrotum is oblique, from above 
 downwards, and from before backwards. 
 
 The EPIDIDYMIS is seen attached to its posterior border. 
 This presents an upper large extremity, named the globus 
 major, and a lower small one called the globus minor; the 
 middle portion is named the body. The epididymis is partly 
 covered by the tunica vaginalis. Having examined the ex- 
 terior of the testicle, the tunica albuginea should be divided, 
 and the glandular substance carefully removed, for the pur- 
 pose of studying the structure of this tunic. 
 
 The TUNICA ALBUGINEA, Fig. 184 (2), is the proper cap- 
 sule of the testicle. It is a thick, dense, white fibrous mem- 
 brane. It preserves the form of this organ, and protects 
 its delicate glandular structure. Behind, it forms a projection 
 
432 
 
 OF THE PELVIS. 
 
 Fig. 184. 
 
 internally, which is named the corpus Highmorianum, or me- 
 diastinum testis, Fig. 184 (a). From this fibrous bands pass 
 off in different directions to be attached 
 at various points to the inner surface 
 of the tunic. These add very much 
 to the strength of the fibrous structure 
 of the testicle, and support the vessels 
 as they penetrate the substance of the 
 gland. The corpus Highmorianum is 
 traversed by the bloodvessels and nerves 
 which enter the interior of the testicle, 
 and, also, by convoluted seminal tubes. 
 It will be observed that from the 
 dense and unyielding character of the 
 tunica albuginea rapid effusion into the 
 interior of the testicle would almost 
 necessarily be attended with a great 
 deal of pain. 
 
 The TUNICA YASCULOSA, or PIA 
 MATER of the testicle, Fig. 184 (4), 
 lines the internal surface of the tunica 
 albuginea, and is reflected around the 
 fibrous bands attached to its inner sur- 
 face. It transmits the vessels to every 
 part of the interior of the organ. 
 
 The GLANDULAR PORTION of the 
 testicle consists of a great number of 
 seminal tubes. These may be drawn 
 out with the forceps to the extent of a foot or more ; when 
 this is done they appear at first like exceedingly fine, deli- 
 cate threads, just unravelled from a network. They adhere 
 very slightly to each other, and may be easily separated 
 when allowed to float in water. They are arranged in lobes 
 of a conical shape, and of different sizes ; the bases of which 
 look forwards, and the apices backwards. There are from 
 three to four hundred of these lobes or bundles of convo- 
 luted tubes. Some of them commence by a blind extremity, 
 and others are joined together so as to form loops. 
 
 The TUBULI SEMINIFERI, Fig. 185 (3, 3), unite to form 
 about twenty tubes, which are nearly straight ; these enter 
 
 A TRANSVERSE SECTION 
 
 OF THE TESTICLE. 1. The 
 cavity of the tunica vagi- 
 nalis. 2. The tunica albu- 
 ginea. 3. Corpus Highmo- 
 rianum or mediastinum 
 testis. The cut ends of the 
 vessels below the figure be- 
 long to the rete testis ; those 
 above, to the bloodvessels 
 of the testicle. 4. Tunica 
 vasculosa of the testis. 5. 
 One of the lobules of the 
 tubuli seminiferi terminat- 
 ing in a vas rectum. 6. A 
 section of the epididymis. 
 
DISSECTION OF THE TESTICLES. 
 
 433 
 
 Fig. 185. 
 
 the corpus Highmorianum. They are termed the tubuli recti, 
 or vasa recta. These open into the rete testis, which consists of 
 a network of tubes, in the anterior part of the corpus Highmo- 
 rianum. From the rete testis from ten 
 to twenty tubes pass through the tunica 
 albuginea. They are called the vasa 
 efferentia. These are at first straight, 
 but become convoluted, and form mass- 
 es of a conical shape, which are named 
 the coni vasculosi. These cones form the 
 globus major or head of the epididymis, 
 and by uniting together form a single 
 tube, called the canal of the epididymis. 
 This tube, after forming the body and 
 the globus minor or tail of the epididy- 
 mis, terminates in the vas deferens. 
 
 The VAS DEFEKENS, Fig. 185 (10), 
 and Fig. 186 (e, e), commences at the 
 lower end of the globus minor, and is 
 directed upwards on the inner side of 
 the epididymis. It enters the spermatic 
 cord at the upper part of the testicle, 
 and ascends in the posterior part of it 
 to the internal abdominal ring, where 
 it leaves the cord, and turning short 
 round the epigastric artery, passes down- 
 wards and inwards over the external 
 iliac vessels, and enters the pelvis. In 
 the pelvis it crosses over the ureter, 
 gets between the rectum and the blad- 
 der, and passes downwards and for- 
 wards, on the inner side of the vesicula 
 seminalis, to the upper border of the 
 prostate gland, where it unites with the ductus vesiculce, semi- 
 nalis, to form the ductus ejaculatorius communis. 
 
 The vas deferens is composed of an inner mucous, and an 
 outer fibrous layer. The latter is very thick and firm, so 
 that the tube can be distinctly felt in the spermatic cord of 
 the living subject. The vas deferens is about two feet in 
 length. Its size does not vary much from its commencement 
 37 
 
 A VIEW OP THE MINUTE 
 STRUCTURE OF THE TESTIS. 
 1, 1. Tunica albuginea. 
 2,2. Corpus Highmorianum. 
 3. 3. Tubuli seminiferi con- 
 voluted into lobes. 4, 4. 
 Vasa recta. 5. Bete testis. 
 6. Vasa efferentia. 7. Coni 
 vasculosi constituting the 
 globus major of the epididy- 
 mis. 8. Body of the epidi- 
 dymis. 9. Its globus minor. 
 10. Vas deferens. 11. Vas 
 aberrans, or blind duct. 
 
434 
 
 OF THE PELVIS. 
 
 Fig. 186. 
 
 until it reaches the bladder, where it enlarges, and becomes 
 sacculated. 
 
 The VAS ABERRANS, Fig. 185 (i i), is a small tube which 
 is sometimes found arising from the globus minor, or the 
 commencement of the vas deferens, and extending a short 
 distance upwards in the spermatic cord. \t terminates in a 
 blind extremity. Its use is not known. 
 
 The YESICUL^; SEMINALES, Fig. 186 (7, 7), are two saccu- 
 lated bodies, situated on the base 
 of the bladder, above the prostate 
 gland, and in front of the rectum. 
 They are each about two inches in 
 length, and half an inch in breadth. 
 They approach each other from 
 above downwards, so as to leave a 
 triangular space between them, in 
 which the vasa deferentia are situ- 
 ated. When fully dissected out, 
 each one is found to be from four 
 to five inches in length. They are 
 lined by mucous membrane, outside 
 of which is a proper fibrous layer. 
 They also receive a layer from the 
 prostatic fascia, which attaches them 
 to the bladder. Each one termi- 
 nates in a short tube, the ductus 
 vesiculce seminalis. 
 
 THE POSTERIOR ASPECT OP 
 THE MALE BLADDER; THE SE- 
 ROUS COVERING IS REMOVED IN 
 ORDER TO SHOW THE MUSCULAR 
 
 COAT. 1. The body of the blad- 
 der. 2. Its fundus. 3. Its in- 
 ferior fundus or base. 4. The 
 urachus. 5, 5. The ureters. 6, 6. 
 The vasa deferentia. 7, 7. The 
 vesiculao seminales. 
 
 The DUCTUS EJACULATORIUS COM- 
 MUNIS, Fig. 181 (s), is about an inch 
 in length. It passes forwards, up- 
 wards, and somewhat inwards, be- 
 tween the middle and lateral lobes 
 of the prostate gland to open on 
 
 the caput gallinaginis, in the floor of the prostatic portion of 
 the urethra. At first the two ejaculatory ducts are a little 
 distance apart, but lie close to each other in the latter part of 
 their course. Their walls in the prostate gland are very 
 thin, and some care is requisite to dissect them out entire. 
 
 The SPERMATIC CORD is composed of the vas deferens and 
 the spermatic vessels and nerves. It extends from -the back 
 
RELATIONS OF PELVIC VISCERA IN THE MALE. 435 
 
 part of the testicle to the internal abdominal ring. The left 
 cord is somewhat the longest. The spermatic artery is a branch 
 from the aorta. It enters the testicle through the corpus 
 Highmorianum, and divides into numerous small branches, 
 which ramify in the substance of the gland. The spermatic 
 veins commence in the testicle, and leave it in company with 
 the artery. Just above the testicle they form a plexus named 
 the plexus pampiniformis. They contain no valves. Those on 
 the right side terminate by a single trunk in the ascending 
 cava, and those on the left side in the renal vein. The nerves 
 of the testicle are derived from the plexus which accompa- 
 nies the spermatic artery. 
 
 EELATIONS OF THE PELVIC VISCERA IN THE MALE. 
 
 The pelvic viscera of the male consist of the rectum, the 
 bladder, the vesiculce seminales, and the prostate gland. The 
 rectum occupies the posterior part, and the other organs the 
 anterior part. 
 
 In studying the relations of the RECTUM, it may be divided 
 into two parts, the upper and lower; the first being in direct 
 relation with the peritoneum, and the last having no serous 
 covering. 
 
 The upper part, Fig. 187 (i 6), extends downwards to the 
 recto-vesical fascia, or to within about three-quarters of an 
 inch of the prostate gland. The whole of this part is co- 
 vered in front, and partly on the sides, by the peritoneum, 
 and is in relation with the bladder, and usually with the 
 small intestines ; the superior portion is also covered behind 
 by peritoneum, except a small space between the laminae of 
 the mesorectum. Below it is in apposition with the sacrum, 
 the pyriform muscles, the branches of the internal iliac arte- 
 ries, the sacral nerves, and the ureters, especially the one on 
 the left side. 
 
 The lower part, Fig. 187 (i s), is in relation behind and on 
 the sides with the sacrum and coccyx, and the coccygeus 
 and levatores ani muscles. It has in front of it, commencing 
 above, first, the vesiculae seminales and the triangular space 
 between them on the base of the bladder; second, the pros- 
 tate gland; third, the membranous portion of the urethra 
 
436 OF THE PELVIS. 
 
 and the bulb. Some portions of the rectum are separated 
 from the surrounding parts by a considerable quantity of 
 adipose and areolar tissue. 
 
 As the BLADDER, Fig. 187 (s, 4, s), varies in size according 
 as it is empty or distended, its relations to contiguous parts 
 are necessarily modified. When empty, it is in relation an- 
 
 Fig. 187. 
 
 A SIDE VIEW OF THE VISCERA OF THE MALE PELVIS, IN SITTJ. THE RIGHT SIDE 
 
 OP THE PELVIS HAS BEEN REMOVED BY A VERTICAL SECTION MADE THROUGH THE 
 OS PUBIS NEAR THE SYMPHYSIS ; AND ANOTHER THROUGH THE MIDDLE OF THE SA- 
 CRUM. 1. The divided surface of the os pubis. 2. The divided surface of the 
 sacrum. 3. The body of the bladder. 4. Its fundus; from the apex is seen 
 passing upwards, the urachus. 5. The base of the bladder. 6. The ureter. 7. 
 The neck of the bladder. 8, 8. The pelvic fascia; the fibres immediately above 
 7 are given off from the pelvic fascia, and represent the anterior ligaments of the 
 bladder. 9. The prostate gland. 10. The membranous portion of the urethra, be- 
 tween the two layers of the deep perineal fascia. 11. The deep perineal fascia 
 formed of two layers. 12. One of Cowper's glands between the two layers of deep 
 perineal fascia, and beneath the membranous portion of the urethra. 13. The bulb 
 of the corpus spongiosum. 14. The body of the corpus spongiosum. 15. The 
 right crus penis. 16. The upper part of the rectum. 17. The recto-vesical fold of 
 peritoneum. 18. The lower portion of the rectum. 19. The right vesicula setni- 
 nalis. 20. The vas deferens. 21. The rectum covered by the descending layer of 
 the pelvic fascia. 22. A part of the levator ani muscle investing the lower part of 
 the rectum. 23. The external sphincter ani. 24. The interval between the deep 
 and superficial perineal fascia ; they are seen to be continuous beneath the number. 
 25. Peritoneum covering the upper and back part of the bladder. 
 
 teriorly with the symphysis pubis, the pubic bones, and obtu- 
 rator muscles; and when distended, with the anterior walls 
 of the abdomen. In the latter case, the peritoneum is raised 
 
EELATIONS OF PELVIC VISCEEA IN THE MALE. 437 
 
 up so as to leave a non-peritoneal surface above the symphy- 
 sis, when the bladder can be cut into for the purpose of re- 
 moving calculi or evacuating its contents without injuring 
 the peritoneum. It can also be perforated through the sym- 
 physis. Posteriorly, it is in contact, above, with the rectum 
 and with the small intestines, and, when filled, with the sig- 
 moid flexure of the colon ; below, with the vesiculae semi- 
 nales, the vasa deferentia, and the rectum. Sometimes, and 
 especially when empty, the recto- vesical cul-de-sac extends 
 down to the prostate gland and interposes between the vesi- 
 cal triangle and the rectum. It is through this triangular 
 space that the bladder is sometimes perforated from the 
 rectum. When this operation is performed it should be 
 done close to the prostate gland to avoid the peritoneum, 
 and in the median line, so as not to injure the vesiculse 
 seminales and the vasa deferentia. Laterally, the bladder is 
 in relation on each side above, with the remains of the 
 hypogastric artery and the vas deferens; and below, with 
 the levator ani muscle and the pelvic fascia. Its neck, Fig. 
 187 (7), is in apposition with the prostate gland. 
 
 The bladder is retained in situ by ligaments, by fascia, 
 and by the peritoneum. The ligaments of the bladder are 
 designated the true and the false. The false consists simply 
 of two folds of peritoneum, one on each side of the cul-de-sac 
 between the bladder and the rectum; they are sometimes 
 called the posterior ligaments of the bladder. The anterior 
 true ligaments arise from the lower part of the pubic bones, 
 and are inserted into the neck of the bladder. The lateral 
 true ligaments are derived from the pelvic fascia, and will be 
 described in connection with it. 
 
 The PROSTATE GLAND, Fig. 188 (2), is in relation, above, 
 with the anterior ligaments of the bladder ; on the sides with 
 the levatores ani, and below, with the rectum. It is from two 
 to two and a half inches above the anus. Its base corre- 
 sponds to the neck of the bladder and its apex to the mem- 
 branous portion of the urethra. 
 
 The relations of the membranous portion of the urethra 
 and the bulb will be described in this place preparatory to 
 the examination of the perineal fasciae. 
 
 The MEMBRANOUS PORTION of the urethra, Fig. 187 (i o), 
 is situated below the arch of the pubes and extends from the 
 
 37* 
 
438 OF THE PELVIS. 
 
 prostate gland to the bulb. It is in front of the rectum, from 
 which it is separated by a triangular space, the base of which 
 looks downwards and forwards towards the bulb and the pe- 
 
 Fig. 188. 
 
 ANTERO-POSTERIOR SECTION OF THE PELVIS OF A MALE, EXHIBITING THE VISCERA 
 IN THEIR NATURAL SITUATION, AND THE CURVATURES OF THE URETHRA. 1. The 
 bladder. 2. The prostate. 3, 3. The urethra, laid open through its whole extent. 
 4. The seminal vesicle, laid open. 5. The spongy body, seen both above and below 
 the urethra. 6. The bulb of the spongy body. 7. The cavernous body of the penis. 
 8. The right side of the scrotum. 9. The rectum. 10. The peritoneal lining of 
 the abdominal muscles. 11. The peritoneal investment of the bladder. 12. Tho 
 point where the peritoneum is reflected from the bladder upon the rectum. 13. 
 The section of the pubic syinphysis. 14. A line marking the situation of the tri- 
 angular ligament. 
 
 rineal centre ; the apex is directed upwards and backwards 
 to the point where the prostate gland rests against the rec- 
 tum. .It is about an inch below the symphysis, from which 
 it is separated by an elastic and spongy structure, the mus- 
 cles of Gruthrie and Wilson, and the deep perineal fascia. 
 
 The BULB of the corpus spongiosum, Fig. 187 (i s), corre- 
 sponds to the upper part of the pubic arch, and is anterior 
 to the triangular ligament. It is about three-fourths of an 
 inch in front of the rectum. It is covered below by the in- 
 
DISSECTION OF THE VESSELS AND NERVES. 439 
 
 tegument, the common superficial fascia, the superficial pe- 
 rineal fascia, and the ejaculatores urinse muscles. 
 
 DISSECTION OF THE VESSELS AND NERVES IN THE PELVIC 
 
 CAVITY. 
 
 The principal vessels and nerves in the pelvic cavity can 
 be examined without removing any portion of the bones 
 that form its parietes ; j;o make a thorough dissection of them, 
 however, the os innominatum on one side should be disar- 
 ticulated and removed; or any portion of it may be cut 
 away, including any part of the sacrum that may be found 
 necessary in the progress of the dissection. The saw, or a 
 mallet and chisel may be used for this purpose. To trace 
 the vessels which supply the bladder and rectum, these organs 
 should be moderately distended, the former with air, and the 
 latter with cotton or tow. If the arteries be well injected 
 but little difficulty will be encountered after the peritoneum 
 has been removed, in exposing all the principal branches, as 
 far as the organs which they supply or the openings through 
 which they leave the pelvic cavity. 
 
 The Middle Sacral Artery seems to be a continuation of the 
 aorta greatly diminished in size. It extends in the median 
 line from the bifurcation of the aorta to the coccyx, passing 
 over the body of the last lumbar vertebra and the sacrum. 
 In its course it gives off small branches, some of which anas- 
 tomose with the lateral sacral arteries, and others enter the 
 meso-rectum. 
 
 The INTERNAL ILIAC or HYPO GASTRIC ARTERY, Fig. 189 
 (e), Fig. 190 (e), furnishes most of the branches found in the 
 pelvis. It arises from the bifurcation of the common iliac 
 artery opposite the sacro-iliac symphysis, and descending 
 into the pelvis terminates near the upper border of the great 
 sacro-sciatic foramen. It varies in length from an inch to 
 an inch and a half. Near its origin it is separated from the 
 peritoneum by the ureter. The lumbo-sacral nerve lies be- 
 hind it ; the internal iliac vein is situated behind and a little 
 to the outer side of it. In the foetus the internal iliac is 
 continued to the umbilicus, where it becomes the umbilical 
 artery. Commencing at the origin of the vesical artery a 
 
440 
 
 OF THE PELVIS. 
 
 ligamentous cord will be observed extending on the side of 
 the bladder to the anterior parietes of the abdomen, and 
 thence to the umbilicus ; this is the remains of the hypo- 
 gastric artery of the foetus. The folds of peritoneum formed 
 by these fibrous cords, there being one on each side, were 
 noticed in the examination of that membrane. The vasa 
 deferentia pass over these cords. 
 
 The branches of the internal iliac artery vary so much in 
 their origin that no fixed rule, perhaps, need be observed in 
 describing them. They will be noticed in the order in which 
 it will be found most convenient to examine them in the dis- 
 section. The internal iliac very frequently divides into two 
 principal trunks, from which the branches proceed. They 
 are designated the anterior and posterior divisions, Fig. 189 
 (T, e). When this division exists, the latter usually gives off 
 
 Fig. 189. 
 
 A DIAGRAM OP THE ILIAC ARTERIES AND THEIR BRANCHES. 1. The aorta. 2. 
 
 The left common iliac artery. 3. The external iliac. 4. The epigastric artery. 5. 
 The internal circumflex ilii. 6. The internal iliac artery. 7. Its anterior division. 
 8. Its posterior division. 9. The umbilical artery giving off (10) the superior vesical 
 artery. After the origin of this branch the umbilical artery becomes converted 
 into a fibrous cord the umbilical ligament. 11. The internal pudic artery passing 
 behind the spine of the ischium (12) and small sacro-sciatic ligament. 13. The 
 middle hemorrhoidal artery. 14. The sciatic artery, also passing behind the 
 small sacro-sciatic ligament to escape from the pelvis. 15. Its inferior vesical 
 branch. 16. The ilio-lumbar, the first branch of the posterior division (8) ascend- 
 ing to anastomose with the internal circumflex ilii artery (5), and form an arch 
 along the crest of the ilium. 17. The obturator artery. 18. The lateral sacral. 19. 
 The gluteal artery escaping from the pelvis through the upper part of the great 
 sacro-sciatic foramen. 20. The sacra media. 21. The right common iliac artery 
 cut short. 22. The femoral artery. 
 
DISSECTION OF THE VESSELS AND NEKVES. 
 
 the gluteal, the ilio-lumbar, and the lateral sacral, while the 
 former supplies the remaining branches or arteries. 
 
 The ilio-lumbar artery. Fig. 189 (ie), arises from the back 
 part of the internal iliac, near its origin, passes outwards be- 
 hind the external iliac artery and vein and the psoas mag- 
 nus, to divide into a lumbar and an iliac branch. The former 
 passes upwards, and sends off branches to the psoas and 
 quadratus lumborum muscles, to the spinal canal, and to 
 anastomose with the last lumbar artery. The latter passes 
 downwards and outwards as far as the crest of the ilium, 
 where it anastomoses with the internal circumflex ilii ; some- 
 times it is found ramifying in the iliacus internus muscle, or 
 beneath it on the surface of the bone. By means of this 
 artery an anastomotic connection is established between the 
 internal and external iliac arteries. 
 
 The obturator artery, Fig. 189 (i 7), not unfrequently has its 
 origin from some other than the internal iliac artery, as the 
 external iliac, the epigastric, or the femoral. The course it 
 takes to reach the inner part of the thigh will vary with its 
 origin. When it arises from the internal iliac it passes hori- 
 zontally forwards just below and on the inner side of the 
 brim of the pelvis to the sub-pubic groove in the upper border 
 of the obturator foramen. The obturator nerve lies above 
 it, but follows the same course. When it arises from either 
 of the other arteries mentioned above, it passes inwards over 
 the brim of the pelvis, to enter the sub-pubic groove. When 
 it has its origin from the femoral artery, however, it first 
 passes upwards through the femoral ring, and then inwards. 
 Its relations to the femoral ring are noticed in connection 
 with the anatomy of femoral hernia. It usually gives off 
 several small branches in the pelvis, in its course to the 
 thigh ; the most important of which is a branch that anas- 
 tomoses with the epigastric; sometimes this is quite large, 
 and deserves special notice from its relation to femoral 
 hernia. Having passed throiigh the obturator foramen, the 
 obturator artery divides into two principal branches, an 
 internal and external. These are distributed to the muscles 
 on the inner and back part of the thigh. The external 
 division sends a small branch through the notch at the lower 
 part of the acetabulum to supply the hip-joint; by means of 
 the ligamentum teres the head of the femur is partly supplied 
 from this branch. 
 
442 
 
 OF THE PELVIS. 
 
 Fig. 190. 
 
 The vesical arteries, Fig. 190 
 (11), consist of two principal 
 branches, a superior and an in- 
 ferior. The former is usually a 
 continuation of that part of the 
 hypogastric artery in the foetus, 
 which, instead of being con- 
 verted into a ligamentous cord, 
 remains pervious after birth. 
 It ramifies on the back, sides, 
 and fundus of the bladder; 
 sometimes a branch extends 
 upwards from the summit to- 
 wards the umbilicus. The latter, 
 or vesico-prostatic, commonly 
 arises directly from the internal 
 iliac, and is distributed to the 
 neck and lower part of the 
 bladder, to the prostate gland, 
 to the corresponding seminal 
 vesicle, and the upper part of 
 the urethra. A small branch 
 is sent to the vas deferens, 
 named the deferential artery; 
 also another one to the ureter. 
 The inferior artery of the blad- 
 der varies very much in its 
 origin. Besides these branches 
 the bladder is generally suppli- 
 ed with several small branches 
 derived from other sources. 
 
 THE ARTERIES OF THE PELVIS AND THIGH, AS SEEN FROM THE INNER SIDE, BY 
 A VERTICAL SECTION. 1. Inferior extremity of the abdominal aorta, just where 
 it divides into the iliac arteries. 2. Right primitive iliac. 3. Right external iliac. 
 4. Origin of epigastric artery. 5. Internal eircumflex ilii. 6. Hypogastric or internal 
 iliac artery. 7. Ilio-lumbar. 8. Gluteal. 9. Obturator. 10. Lateral sacral. 11. 
 Vesical arteries cut off. 12. Middle hemorrhoidal. 13. Internal pudic. 14. Ischi- 
 atic. 15. Commencement of the femoral artery at the crural arch. 16. Point 
 where it passes through the adductor magnus. 17, 20, 21. Arteria profunda. 18. 
 Internal circumflex. 19, 19, 19. First, second, and third perforating arteries. 22. 
 A branch to the vastus internus. 23. Femoral artery passing through the canal 
 formed by the tendon of the adductor magnus. 24. The anastomotica. 25. A 
 branch to the sartorius muscle. 26. Popliteal artery. 27. The same artery be- 
 hind the knee-joint under the soleus muscle. 28. A supernumerary articular 
 artery. 29. Superior internal articular artery. 30. Inferior internal articular 
 artery. 31. Anastomosis of the three last with anastomotica. 
 
DISSECTION OF THE VESSELS AND NERVES. 443 
 
 The middle hemorrhoidal artery, Fig. 190 (12), arises from 
 the internal iliac, sometimes from the inferior vesical or the 
 internal pudic, passes to the side of the rectum, where it 
 anastomoses with the superior and inferior hemorrhoidal 
 arteries. It is very irregular in its origin, and sometimes is 
 absent. 
 
 The uterine artery arises from the internal iliac, and, pass- 
 ing between the layers of the broad ligament, reaches the 
 uterus just above the os tincse. It then ascends on the bor- 
 der to the fundus, giving off branches in its course, which 
 ramify on the anterior and posterior surfaces of the uterus ; 
 some of these penetrate its substance, others anastomose in the 
 median line with the corresponding branches on the opposite 
 side. It sends small branches to the bladder and ureters. 
 During the period of pregnancy, the uterine arteries attain 
 to a great size, and become exceedingly tortuous. 
 
 The ovarian arteries anastomose freely with the uterine. 
 They arise from the aorta, and pursue a course downwards 
 similar to that of the spermatic arteries in the male until 
 they reach the brim of the pelvis, when they are directed 
 inwards to get between the layers of the broad ligaments. 
 Each one penetrates the ovary at its attached border. In 
 their course to the ovaries they are very much convoluted. 
 They send branches to the Fallopian tubes and to the round 
 ligaments; the latter branches accompany the Fallopian 
 tubes to their destination. 
 
 The vaginal artery arises in common with the inferior 
 vesical, or from the hypogastric, just before or after that 
 artery. It passes downwards on the side of the vagina to 
 near its external orifice, when it gets behind it, between the 
 vagina and rectum, to anastomose with branches from the 
 opposite side. It sends branches in its course to the bladder 
 and the urethra, also to the rectum. 
 
 The lateral sacral arteries, Fig. 190 (i o), usually consist of 
 two, a superior and inferior, on each side. They arise close 
 to each other just above the gluteal. The superior passes 
 downwards and inwards to the first sacral foramen, which it 
 enters to reach the sacral canal, where it divides into two 
 branches ; one of these escapes from the canal through the 
 corresponding posterior sacral foramen, and is distributed to 
 the muscles and integument of the back, while the other 
 ramifies in the canal. The inferior descends in front of the 
 
444 OF THE PELVIS. 
 
 pyriformis muscle and sacral nerves and on the inner side 
 of the anterior sacral foramina to the side of the coccyx. It 
 gives off small branches which enter the sacral foramina, 
 and have each one of them the same distribution as the 
 superior lateral sacral artery. Besides the branches which 
 enter the sacral canal, these arteries give off branches that 
 anastomose with the middle sacral artery and ramify on the 
 anterior surface of the sacrum ; and also others which go to 
 the pyriformis muscle and the sacral nerves. 
 
 The gluteal artery, Fig. 190 (s), from its size, might be 
 regarded as a continuation of the internal iliac. It escapes 
 from the pelvis at the upper part of the great sacro-sciatic 
 foramen between the gluteus medius and pyriformis muscles. 
 In its course downwards and backwards it passes between 
 the-lumbo-sacral and the first sacral nerve. In the pelvis it 
 gives off a nutritious branch to the ilium and one or more 
 muscular branches. Having escaped from the pelvis it divides 
 into a superficial and a deep branch, which will be noticed in 
 the dissection of the gluteal region. 
 
 The sciatic or ischiatic artery, Fig. 190 (14), varies in its 
 origin. Not unfrequently it arises in common with the in- 
 ternal pudic, from which it does not separate until just before 
 it leaves the pelvis. It passes downwards in front of the 
 pyriformis muscle and sacral plexus of nerves to the lower 
 part of the great sacro-sciatic foramen, where it is placed 
 between the pyriformis and superior gemellus muscles, having 
 the great sciatic nerve on the inner side of it and the internal 
 pudic artery behind it. It gives off in its course in the 
 pelvis the coccygeal branch, which perforates the great sacro- 
 sciatic ligament and ramifies on the dorsum of the coccyx. 
 As it leaves the pelvis, it sends off a branch named the comes 
 nervi ischiadici to accompany the great sciatic nerve. Its 
 course and distribution outside the pelvis will be examined 
 in the dissection of the gluteal region and upper and back 
 part of the thigh. 
 
 The internal pudic artery, Fig. 190 (t 3), has the same direc- 
 tion and relations in the pelvis as the sciatic artery, which it 
 accompanies to the spine of the ischium, around which it 
 winds to enter the perineum. Its course and branches in 
 the perineum will be observed in the dissection of that 
 region. It is in some respects the most important branch 
 given off from the internal iliac, to be studied. This is 
 
DISSECTION OF THE VESSELS AND NERVES. 445 
 
 owing to its liability to injury in cutting for stone and 
 in other operations in the perineum. Before it leaves the 
 pelvis it supplies branches to the levator ani muscle, the 
 rectum, the bladder, the vesiculee seminales, and to the pros- 
 tate gland. Its distribution in the female differs from that 
 in the male. "While within the pelvis in the female, besides 
 sending branches to the bladder and rectum, it sends branches 
 to the vagina; in the perineum the branches that correspond 
 to those which go to the penis in the male are distributed to 
 the clitoris. 
 
 The INTERNAL ILIAC VEIN is placed on the inner side of 
 the internal iliac artery with which it corresponds. It re- 
 ceives the blood from the veins that accompany the branches 
 of the internal iliac artery, and also from the vesico-prostatic 
 plexus, including that portion of the blood contained in the 
 hemorrhoidal plexus which does not find its way to the infe- 
 rior mesenteric vein and thence to the portal vein. It has 
 no valves. It is exceedingly important that every student 
 should thoroughly understand the plexuses of veins con- 
 nected with the rectum and genito-urinary apparatus. It 
 will be seen that a part of the blood from these plexuses 
 reaches the heart through the internal and common iliac 
 veins and the vena cava, while another portion passes 
 through the mesenteric and portal veins to the liver, and 
 thence through the hepatic veins and vena cava to the heart. 
 Each artery has its venae comites, which unite to open into 
 their main trunk by a common orifice. 
 
 The ilio-lumbar vein opens into the common iliac. It is 
 united to the veins which escape from the spinal canal 
 through the lower lumbar intervertebral foramina ; also to 
 a vein which lies in front of the last lumbar vertebra, and to 
 the lateral sacral veins by an anastomosing branch. 
 
 The middle sacral and the lateral sacral veins correspond to 
 the arteries of the same names. The former arises in front 
 of the coccyx, and passes upwards to terminate in the left 
 common iliac vein. Not unfrequently a communicating 
 branch is found connecting this vein with the hemorrhoidal 
 plexus, and also with the vesical plexus. The latter consist 
 of two or more veins, which open into the common iliac 
 vein. 
 
 The veins which accompany the gluteal, the sciatic, the 
 88 
 
446 OF THE PELVIS. 
 
 obturator, and the internal pudic artery, require no particular 
 description. 
 
 The hemorrhoidal veins and plexus are situated in the pa- 
 rietes of the lower part of the rectum. They consist of the 
 superior, middle, and inferior hemorrhoidal veins, which 
 empty, the superior into the inferior mesenteric, and the mid- 
 dle and inferior into the internal iliac vein, or a branch of it. 
 A venous network is found just beneath the mucous mem- 
 brane/ and close to the anus. Hemorrhoids are very fre- 
 quently caused by the dilatation of the veins that form this 
 network or plexus, as was noticed in the dissection of the 
 rectum. 
 
 The vesico-prostatic plexus, Fig. 199 (9), is situated in the 
 upper pouch or pocket formed by the deep perineal and pel- 
 vic fasciae, by which the veins that form a portion of the 
 plexus are prevented from becoming very much distended. 
 It covers the prostate gland and the neck of the bladder. 
 In cutting for stone, this plexus is necessarily more or less 
 wounded, which may give rise to a good deal of hemorrhage, 
 the amount depending on the condition of the veins at the 
 time of the operation. Behind, it communicates with the 
 hemorrhoidal plexus; in front and below with the veins 
 which surround the membranous portion of the urethra ; it 
 also receives the contents of the dorsal veins of the penis. 
 These veins, after passing through the sub-pubic ligament 
 and deep perineal fascia, unite to form a single trunk, which 
 divides these into a right and left vein, in order to join the 
 prostatic plexus on both sides of the prostate gland. The 
 veins from the dorsum of the penis are kept constantly open 
 where they perforate the dense fibrous structure of which the 
 sub-pubic ligament and deep perineal fascia are composed. 
 They also communicate freely with the deep veins, or those 
 which accompany the branches of the internal pudic artery. 
 
 The spermatic veins were noticed in the dissection of the 
 testicle. They communicate with the dorsal veins of the 
 penis, and with the pudic veins. There is occasionally a 
 communication existing between the spermatic vein and the 
 portal system. 
 
 The ovarian veins are formed by branches derived from the 
 uterus, the ovaries, and the Fallopian tubes. They accom- 
 pany the ovarian arteries, and have the same termination as 
 the spermatic veios. 
 
DISSECTION OF THE VESSELS AND NEKVES. 447 
 
 The vaginal plexus of veins surrounds the vagina. Near 
 the vulva the plexus is composed of a great number of veins, 
 many of which have their origin in the erectile tissue that is 
 found around the external orifice of the vagina. The veins 
 of the vaginal plexus communicate behind, with the hemor- 
 rhoidal plexus, and before, with the vesical plexus. 
 
 The uterine veins correspond on the exterior surface of the 
 uterus to the uterine arteries. They arise from venous canals, 
 or sinuses, which traverse the substance of the uterus, without, 
 however, being tortuous like the arteries. The veins, as 
 well as the arteries of this organ, increase greatly in size 
 during the period of pregnancy. 
 
 The nerves which supply the pelvic viscera are derived 
 from the lumbo-sacral, the anterior sacral, and the sympa- 
 thetic system. 
 
 Besides the visceral nerves, there are several small branches 
 derived from the sacral nerves or plexus, and appropriated to 
 the muscles within the pelvis and perineum. There is also 
 found in the pelvis a branch from the lumbar plexus called 
 the obturator nerve, which from its position should be exa- 
 mined first. 
 
 The obturator nerve, Fig. 191 (e), arises from that portion 
 of the lumbar plexus which is formed by the third and fourth 
 lumbar nerves. To reach the pelvis, it first passes through 
 the psoas magnus muscle, and then runs for some distance on 
 its inner side; it then crosses over the brim of the pelvis, 
 and gets below the external iliac vein and above the obtura- 
 tor artery, which it accompanies to the sub-pubic groove, 
 when it enters the upper and inner part of the thigh. After 
 perforating the psoas muscle, it passes beneath the bifurca- 
 tion of the common iliac vessels. In the pelvis, near the 
 obturator foramen, it usually gives off one or two articular 
 branches to the hip-joint. As it enters the thigh it divides 
 into the superficial or anterior division, and the deep or posterior 
 division. These are distributed principally to the muscles on 
 the inner part of the thigh, and will be noticed in the dis- 
 section of that region. 
 
 When the obturator accessory nerve, Fig. 191 (n), is present, 
 and of its usual size, it supplies the hip-joint with articular 
 filaments instead of the obturator nerve itself. The accessory 
 nerve has the same origin as the obturator nerve; of which 
 it is sometimes a part for a short distance, when it becomes a 
 
448 
 
 OF THE PELVIS. 
 
 separate nerve. It perforates the psoas muscle, and descends 
 on its inner side to the pubes, which it passes over on the inner 
 side of the ilio-pectineal eminence to get beneath the pecti- 
 neus muscle, where it gives off its articular filaments to the 
 hip-joint and divides into several other branches; one of 
 which descends as low as the upper and back part of the leg, 
 sending in its course a filament to the knee-joint. 
 
 The superior gluteal nerve, Fig. 192 (2), may be examined 
 next. It arises from the lumbo-sacral before it joins the first 
 
 sacral nerve to become a 
 Fig. 191. part of the sacral plexus. 
 
 It escapes from the pelvis 
 in company with the glu- 
 teal artery through the up- 
 per part of the great sacro- 
 sciatic foramen, above and 
 in front of the pyriformis 
 muscle, and divides into 
 two branches which cor- 
 respond in their distri- 
 bution with the gluteal 
 artery. It supplies the 
 gluteus medius, minimus, 
 and tensor vaginas femoris 
 muscles. 
 
 The lumbo-sacral nerve, 
 Fig. 192 (i), is formed by 
 the union of the descend- 
 ing portion of the fourth 
 lumbar, and the fifth lum- 
 bar. It enters the pelvis, 
 and assists in forming the 
 sacral plexus. 
 
 There are six anterior 
 sacral nerves, including 
 what is sometimes called 
 
 THE LUMBAR PLEXUS AND ITS BRANCHES (SLIGHTLY ALTERED FROM SCHMIDT). 
 a. Last rib. b. Quadratus lumborum muscle, c. Oblique and transverse muscles, 
 cut near the crest of the ilium, d. Os pubis. e. Adductor brevis muscle. /. Pec- 
 tineus. g. Adductor longus. 1. Superior musculo-cutaneous branch. 2. Middle 
 musculo-cutaneous branch. 3. Inferior musculo-cutaneous branch. 4. Anterior 
 crural nerve. 5. Accessory obturator. 6. Obturator nerve. 7. Genito-crural nerve 
 dividing into two at its origin from the plexus. 8, 8. Gangliated cord of the 
 sympathetic nerve. 
 
DISSECTION OF THE VESSELS AND NERVES. 449 
 
 I 
 
 the coccygeal nerve. They escape from the sacral or lower 
 part of the spinal canal, through the anterior sacral foramina. 
 
 The first and second nerves are quite large, and of nearly 
 the same size. The first being joined by the lumbo-sacral, 
 passes obliquely downwards over the pyriformis muscle to 
 the sacral plexus. The second nerve proceeds more obliquely 
 outwards than the first to join the plexus. 
 
 The third nerve, as it goes to join the sacral plexus, has a 
 still more oblique direction, being nearly horizontal. It is 
 only about one-fourth the size of the first and second nerves. 
 To the latter nerve it is connected by a filament, which will 
 be seen passing over the pyriformis muscle. 
 
 The fourth nerve is very much smaller than the third. A 
 part of it only goes to join the sacral plexus. The rest of it 
 sends branches to join the hypogastric plexus of the sym- 
 pathetic nerve, one to join the fifth nerve, and others to 
 supply the levator ani, the coccygeus and sphincter ani 
 muscles. 
 
 The fifth nerve usually passes through the foramen formed 
 by the sacrum and coccyx. It is much smaller than the 
 fourth, to which it is joined by a communicating branch; it 
 sends a branch to the sixth nerve. 
 
 The sixth sacral or the coccygeal nerve is generally very 
 small; it emerges at the lower end of the spinal canal; from 
 which point it should be traced. 
 
 It will be observed that of the sacral nerves only the first 
 three, and a part of the fourth, contribute to form the sacral 
 plexus. Each one of them is joined to a ganglion of the 
 sympathetic nerve by a communicating branch; they are 
 also connected to each other by a similar branch. 
 
 The SACRAL PLEXUS, Fig. 192 (4), is formed, as has been 
 seen, by the union of four whole nerves and portions of two 
 others. The whole nerves are the last lumbar and the first 
 three sacral ; the parts are derived from the fourth lumbar 
 and the fourth sacral nerve. The shape of the plexus is tri- 
 angular; its base looks towards the foramina through which 
 the nerves that form it escape from the spinal canal, while 
 its apex corresponds to the beginning of the great sciatic 
 nerve, which is close to the lower part of the great sciatic 
 foramen through which this nerve makes its exit from the 
 pelvis. 
 
 38* 
 
450 
 
 OF THE PELVIS. 
 
 Fig. 192. 
 
 The sacral plexus is more simple in its structure than any 
 other belonging to the spinal system of nerves. 
 
 The plexus lies on the anterior surface 
 of the pyriformis muscle ; in front, it cor- 
 responds to the lower part of the rectum, 
 from which it is separated by a fascia and 
 branches of the internal iliac vessels. In ex- 
 posing the sacral nerves and plexus, much 
 care is requisite to preserve the nerves 
 which arise from them, and which should 
 now be traced to their destination if they 
 end in the pelvis, and to their exit from the 
 pelvis if they go to supply parts outside 
 of it. 
 
 To do this no specific directions can be 
 given, as they vary so frequently in their 
 origin and general arrangement; this is 
 more particularly the case with the nerves 
 which supply the viscera. These may 
 arise partly from the second and third 
 nerves, or partly from the plexus, or al- 
 most wholly from the fourth and fifth 
 nerves. They may go in part directly to 
 the viscera which they supply, as the rec- 
 tum, the bladder, and the prostate gland, 
 in the male ; and, in the female, to the blad- 
 der, the uterus, the vagina, and the rectum ; 
 or they may, some of them at least, join 
 filaments of the sympathetic nerve, as the 
 hypogastric plexus, and, in company with 
 them, reach the same organs. As they are so 
 intimately connected with the hypogastric 
 plexus and the filaments derived from it, 
 the two sets of nerves should be examined 
 
 A DIAGRAM SHOWING THE FORMATION AND BRANCHES OP THE SACRAL PLEXUS. 
 1. The lumbo-sacral nerve, descending to join the sacral plexus, and giving off a 
 large branch. 2. The superior gluteal nerve. 3. The anterior branches of the four 
 upper sacral nerves. 4. The sacral plexus. 5. The internal pudic nerve. 6. The 
 lesser sciatic nerve. 7. The great sciatic nerve. 8. The peroneal nerve. 9. The 
 popliteal nerve. 10. Its sural branches. 11. The posterior tibial nerve dividing 
 inferiorly into the two plantar nerves, 12. 13. The anterior tibial nerve. 14. The 
 musculo-cutaneous nerve, its muscular portion. 15. Its cutaneous portion. 16. 
 The external saphenous nerve, formed by the union of the communicans poplitei, 
 and communicana peronei. 
 
DISSECTION OF THE VESSELS AND NEEVES. 451 
 
 together; they will be referred to again in the dissection of 
 the sympathetic nerve in the pelvis. 
 
 Although a knowledge of these nerves possesses but little 
 value as applied to surgical operations, its value cannot be 
 estimated when viewed in connection with injuries and dis- 
 eases in which the pelvic organs, either in the male or female, 
 are directly or indirectly involved. 
 
 The following are the muscular nerves derived from the 
 sacral plexus or nerves and distributed principally to the 
 muscles in the pelvis and perineum. 
 
 The nerve to the pyriformis, generally, comes from the pos- 
 terior aspect of the plexus, but sometimes it proceeds from 
 one of the sacral nerves before it enters the plexus ; some- 
 times there are two of these small nerves, or one which di- 
 vides it into two branches before penetrating the muscle. 
 
 The nerves to the levator ani are usually two branches of the 
 fourth sacral nerve. Besides these, this muscle commonly 
 receives two or three filaments from the vesical and hemor- 
 rhoidal nerves. The first of these nerves, or those from the 
 fourth sacral nerve, penetrate the pelvic surface of the mus- 
 cle, the largest one near its centre and the other near its 
 anterior border. 
 
 The nerve to the obturator internus proceeds from the upper 
 and anterior portion of the sacral plexus, passes around the 
 spine of the ischium and through the small sacro-sciatic fora- 
 men, when it divides into two or three branches which spread 
 out and penetrate the inner surface of the muscle. 
 
 The inferior hemorrhoidal nerve arises from the posterior 
 part of the sacral plexus near the internal pudic, or from 
 the internal pudic itself, which it accompanies through the 
 small sacro-sciatic foramen to near the upper border of the 
 sphincter ani muscle, where it divides into several small 
 branches. Some of these penetrate the muscle at different 
 points, while others proceed to the integument around the 
 anus ; others still pass forwards and anastomose with the 
 superficial perineal nerve and the perineal branch of the 
 lesser sciatic nerve. The inferior hemorrhoidal nerve corre- 
 sponds in its distribution with the artery of the same name. 
 The sphincter ani is also supplied in part by filaments which 
 proceed to it directly from the fourth and fifth sacral nerves ; 
 and also from the internal pudic. And again, the inferior 
 
452 OF THE PELVIS. 
 
 hemorrhoidal nerve is occasionally wholly cutaneous, sending 
 no filaments to the sphincter muscle. 
 
 The coccygeus muscle is supplied with filaments derived 
 from the fourth and fifth sacral nerves, and the coccygeal 
 nerve. One or two of these nerves, after perforating the 
 coccygeus muscle, become cutaneous, and supply the integu- 
 ment behind the anus and on the back of the coccyx. 
 
 Two small nerves usually arise from the sacral plexus 
 which are distributed to the gemelli and quadratic femoris 
 muscles, and also to the hip-joint. The one that supplies the 
 superior gemellus arises from the plexus near the origin of 
 the internal pudic. The one that goes to the inferior ge- 
 mellus and quadratus femoris arises from the plexus at or 
 near the commencement of the great sciatic nerve, passes 
 downwards behind the superior gemellus and obturator in- 
 ter nus muscles, between them and the capsule of the hip- 
 joint, to reach the deep surface of the muscles to which it is 
 distributed. Besides supplying these muscles, this nerve 
 sends filaments to the hip-joint. 
 
 The internal pudic or superior long pudendal nerve arises 
 from the lower part of the sacral plexus, and soon joins the 
 internal pudic artery which it accompanies through the small 
 sacro-sciatic foramen to the perineum, where it divides into 
 two terminal branches, named the perinea! nerve and the dor- 
 sal nerve of the penis. They will be noticed as they are met 
 with in the dissection of the parts to which they are distri- 
 buted. It may be well, however, to give a brief description 
 of the course and distribution of the branches of the internal 
 pudic nerve in this place. 
 
 The perineal nerve accompanies the internal pudic artery as 
 far as a point nearly opposite to the junction of the tube- 
 rosity and ramus of the ischium. At this place it perforates 
 the obturator fascia, which up to this point in the perineum 
 separated it from the ischio-rectal fossa, and divides into its 
 two terminal branches. One of these, named the superficial 
 perineal nerve, Fig. 195 (2), corresponds to the superficial pe- 
 rineal artery. It is placed in the groove between the erec- 
 tor penis and accelerator urinae muscles, and is distributed to 
 the scrotum, some of its filaments being continued forwards 
 to the integument covering the under surface of the penis. 
 The other branch passes above the transversus perinei mus- 
 cle and sends filaments to the accelerator urinse, to the bulb 
 
DISSECTION OF THE VESSELS AND NERVES. 453 
 
 of the corpus spongiosum, and to the muscles of Wilson 
 and Guthrie. 
 
 The perineal nerve, just before it enters the perineum, gives 
 off a branch which has been called the posterior superficial 
 perineal nerve. It perforates the great sacro-sciatic ligament, 
 enters the ischio-rectal fossa, and passes forwards to be distri- 
 buted to the scrotum in the male, and to the vulva in the 
 female. It anastomoses with the inferior hemorrhoidal and 
 the perineal branch of the small sciatic nerve; and some- 
 times sends branches to the sphincter ani and coccygeus 
 muscles. 
 
 The dorsal nerve of the "penis, instead of perforating the 
 obturator fascia, continues forwards, gets between the layers 
 of the deep perineal fascia, perforates the anterior one, and 
 reaches the dorsum of the penis in company with the artery 
 of the same name. It proceeds forwards to the glans penis, 
 to which it is distributed. It gives off a cutaneous branch 
 which divides into numerous filaments to supply the -skin 
 including the prepuce; it also sends off branches which 
 penetrate the substance of the corpus cavernosum. The cor- 
 responding nerve of the one last described, in the female, 
 is distributed to the clitoris. 
 
 The small or lesser sciatic nerve, Fig. 192 (e), arises from the 
 lower part of the sacral plexus by one, and sometimes by 
 several nervous cords. It leaves the pelvis at the lower part 
 of the great sacro-sciatic foramen, and beneath the pyriformis 
 muscle. At first it is placed on the inner side of the great 
 sciatic nerve, but soon gets behind it. It divides into mus- 
 cular and cutaneous branches. The former supply the glu- 
 teus rnaximus; the latter are divided into the external and 
 internal ; they are distributed to the skin on the outer, back 
 and inner parts of the thigh, one or two branches descending 
 as low as the upper part of the leg. Another branch, 
 named the perineal cutaneous, or the inferior long pudendal 
 nerve, Fig. 218 (4), passes downwards and inwards below the 
 tuber ischii to reach the anterior part of the perineum, where 
 it divides into two branches, which pass forwards, one on 
 each side of the testis, to be distributed to the anterior part 
 of the scrotum, and to the skin on the under part of the 
 penis. It anastomoses with the superficial perineal nerve. 
 
 The great sciatic nerve, Fig. 192 (7), is the terminal branch 
 of the sacral plexus. It escapes from the pelvis through the 
 
454 OF THE PELVIS. 
 
 lower part of the great sacro-sciatic foramen ; sometimes a 
 portion of it pierces the pyriformis muscle. It will be exa- 
 mined in the dissection of the back part of the pelvis and 
 thigh. 
 
 The sympathetic nerve, Fig. 142, presents in the pelvis 
 several ganglia and plexuses. The ganglia are placed to the 
 inner side of the anterior sacral foramina. They consist 
 usually of five on each side. The upper one receives one, 
 and sometimes two communicating branches from the last 
 lumbar ganglion. The lower one on each side is connected 
 by a filament to a single ganglion, called the ganglion impar; 
 this is situated in front of the coccyx. The ganglia of each 
 side are connected by communicating filaments to the sacral 
 nerves, there being two for each ganglion and its correspond- 
 ing nerve; they are quite short. 
 
 There are two hypogastric plexuses in the pelvis, between 
 which there is no direct communication. They are formed 
 by a division of the lumbo-aortic plexus into two, a right 
 and left. They are placed upon the sides of the principal 
 organs in the pelvis, both in the male and female. They 
 receive filaments from several sources in the pelvis, as the 
 sacral ganglia, the inferior mesenteric plexus, and the ante- 
 rior sacral nerves. Small ganglia are found where the sacral 
 nerves unite with those of the plexus. Each hypogastric 
 plexus gives off several plexuses ; they are the following : 
 
 The vesical plexus is situated on the side and lower part of 
 the bladder. It sends off two sets of nerves ; the ascending, 
 which supply the ureters and the upper part of the bladder 
 both in front and behind; and the horizontal, which go to the 
 lower part of the bladder, including the neck. Some of 
 these continue over the prostate gland, forming the prostatic 
 plexus. From these plexuses small filaments penetrate the 
 structure of the bladder and prostate gland. 
 
 From the side of the bladder and the ureter, nerves go to 
 the vas deferens and to the vesicula seminalis, forming a 
 plexus for each one of these organs. From the prostatic 
 plexus nerves proceed to the urethra and to the spongy 
 structure of the penis. They reach the dorsum of the penis 
 by passing through the sub-pubic ligament. 
 
 The rectum is supplied by the superior and middle hemor- 
 rhoidal plexuses. The former comes from the inferior mesen- 
 teric, the latter from the hypogastric plexus. These plexuses 
 are intimately blended with each other. 
 
DISSECTION OF THE PERINEUM. 455 
 
 An ovarian plexus accompanies each of the ovarian arteries 
 from the abdomen ; the ovaries receive filaments also from 
 the uterine nerves. 
 
 The uterine nerves are derived from the hypogastric plexus. 
 They accompany the arteries as they ascend on the lateral 
 borders of the uterus, to supply its fundus anteriorly and 
 posteriorly. From the neck of the uterus nerves proceed to 
 the vagina to form the vaginal plexus. 
 
 DISSECTION OF THE PERINEUM. 
 
 The outlines of the perineal space are indicated by the 
 boundaries of the lower strait of the pelvic cavity. These 
 consist, in front, of the sub-pubic ligament, the descending 
 rami of the pubic bones and the rami of the ischia; late- 
 rally, of the tuberosities of the ischia; and behind, of the 
 sacro-sciatic ligaments and the coccyx. The student should 
 make himself perfectly familiar with the exact position of 
 each one of these parts before he attempts the examination 
 of this region; or he should have a ligamentous pelvis before 
 him when he makes his first dissection of the perineum. He 
 should also have a distinct idea of the position and relations 
 of the following parts: The lower part of the rectum, the 
 bladder, the prostate gland, the membranous portion of the 
 urethra, and the deep perineal fascia or triangular ligament 
 through which it passes, the bulbous portion of the corpus 
 spongiosum, the crura of the corpora cavernosa, and the 
 principal muscles in this region. If he cannot acquire this 
 knowledge by reading a description of these parts with the 
 aid of plates, he should make a special dissection of them. 
 No student should expect to obtain a satisfactory knowledge 
 of the anatomy of the perineum by making a single dissec- 
 tion of it. When he has become familiar with the parts 
 enumerated above, he will find that the study of the fascias 
 involved in the dissection will be greatly facilitated. He 
 will observe that every reflection or attachment of the fascias 
 has a distinct relation to some one or more of these parts ; 
 that they are designed to furnish a floor to the cavity of the 
 pelvis, and to fix and keep the parts in their absolute and 
 relative position. It will also be noticed in the progress of 
 the dissection that they form the boundaries of several spaces 
 
456 OF THE PELVIS. 
 
 which are exceedingly interesting when viewed in reference 
 to the formation of sinuses and abscesses, to effusions of 
 urine, and to the dangers attending operations for the 
 removal of calculi from the bladder, or for any other pur- 
 pose. The great importance of a knowledge of the anatomy 
 of the perineum should be impressed on the mind of every 
 student independently of the idea of his ever being called 
 upon to operate for calculi in the bladder. Yery few in the 
 profession ever have an opportunity 'to cut for stone, while 
 every physician is liable to meet with cases of sinuses, 
 abscesses, and fistulous openings in this region, which he 
 should be able to treat properly. 
 
 To dissect the perineum, the subject must be placed on 
 the back near the end of the table, with a small block 
 under the pelvis. The thighs must be flexed and separated 
 from each other; to keep them in this position, the feet 
 may be fastened by a roller or a cord to the wrists ; or a cord 
 may be attached to one of the thighs near the knee, car- 
 ried under the table and fastened in the same manner to 
 the opposite thigh. If a cord of sufficient length be used, 
 with blocks to support the thighs, the student will have no 
 difficulty in placing and keeping the subject in a favorable 
 position for making his dissection. The rectum should be 
 thoroughly washed out and moderately and evenly distended 
 with tow, cotton, or a piece of a roller gradually introduced 
 into it. The scrotum should be drawn upwards and fastened 
 by hooks. 
 
 The first thing to be done in the dissection is to remove 
 the skin. To do this make an incision from the coccyx to 
 the anus, and thence to the raphe of the scrotum ; and an- 
 other from the nates on each side to the anus. In this way 
 the integument may be raised in four flaps. The skin is so 
 thin at the margin of the anus that some care is requisite to 
 raise it and leave tha superficial fascia. 
 
 The common superficial fascia usually contains a large 
 quantity of adipose substance, especially in the ischio-rectal 
 fosses, spaces situated, one on each side of the anus and lower 
 part of the rectum. This fascia is continuous with the super- 
 ficial fascia of the parts contiguous to the perineum, and 
 must not be confounded with the superficial perineal fascia. 
 To remove it the same incisions may be made as were made 
 to raise the skin. Before doing this, however, the vessels 
 
DISSECTION OF THE PERINEUM. 457 
 
 and nerves which ramify in it should be observed; also the 
 boundaries of the ischio-rectal fossae. 
 
 The arteries which supply the perineum are derived prin- 
 cipally from the internal pudic, a branch of the internal iliac 
 artery. The course of this artery is deep seated, and will be 
 noticed at an advanced stage of the dissection. The prin- 
 cipal branches involved in the removal of the common 
 superficial fascia are the inferior hemorrhoidal, Fig. 194 (i o). 
 These vary in number from one to three on each side. 
 They pierce a layer of the obturator fascia which covers 
 the internal pudic artery, and pass transversely, or nearly 
 so, across the ischio-rectal fossa to the anus. They supply 
 the lower part of the rectum, including the levator and 
 sphincter ani muscles, and the integument around the anus. 
 They are surrounded by the adipose substance which fills 
 the ischio-rectal fossa. The student cannot be too particular 
 in obtaining an accurate knowledge of the position of these 
 vessels. The subcutaneous branches in the anterior part of 
 the perineum are not of sufficient importance to require any 
 special notice here. They consist of small branches of the 
 superficial perineal artery, which is also a branch of the in- 
 ternal pudic, arising from it just after the hemorrhoidal are 
 given off. 
 
 The veins correspond to the arteries and require no par- 
 ticular notice. 
 
 The nerves of the perineum are mainly supplied by the 
 internal pudic, which enters this region in company with the 
 internal pudic artery; and its distribution is nearly the same 
 as that of the artery. It sends hemorrhoidal branches to the 
 lower part of the rectum, and to the levator and sphincter 
 ani muscles. One of its principal divisions is called the 
 superficial perineal nerve, Fig. 195 (2), which passes forwards in 
 company with the superficial perineal artery. In the anterior 
 part of the perineum this nerve becomes subcutaneous and 
 is distributed to the skin in that region and to the scrotum. 
 A small branch, derived from the small sciatic nerve, is also 
 distributed to the integument of the perineum and scrotum; 
 principally, however, to the latter. 
 
 Before examining the boundaries and relations of the 
 ischio-rectal fossae, the sphincter ani and coccygeus muscles 
 may be studied. 
 39 
 
458 OF THE PELVIS. 
 
 The SPHINCTER ANI, Fig. 193 (a), is attached, behind, by 
 tendinous fibres to the coccyx; anteriorly, to the subcuta- 
 
 Fig. 193. 
 
 A VIEW OF THE MUSCLES OF THE PERINEUM OF THE MALE. 1, 1. Kami of the 
 ischia. 2, 2. Tuberosities of the ischia. 3. Posterior face of the coccyx. 4. Por- 
 tion of the great sacro-sciatic ligament. 5. Accelerator urinae. 6. Erector penis. 
 7. Transversus perinei. 8. Sphincter ani. 9. Levator ani. 10. Musculus coccy- 
 geus. 11. Section of the glutens maximus. 12. Adductor longus. 13. Adductor 
 brevis. 14. Adductor magnus. 15. Gluteus maxitnus. 16. The urethra. 17,17. 
 Corpora cavernosa turned up. 18. Spermatic cord turned up. 19. Free extremity 
 of the penis with its integuments. 
 
 neous areolar tissue, and to a fibrous structure just in front 
 of the anus, called the per meal centre, to which the trans- 
 versi perinei and the acceleratores urinse muscles are also 
 attached. It surrounds the lower orifice of the rectum ; 
 is narrow and somewhat pointed before and behind this 
 opening, but an inch or more broad on each side of it. It 
 presents an upper and a lower border. The lower one is 
 separated from the skin by a very thin layer of areolar 
 tissue, while the upper one is blended with the fibres of the 
 levator ani. The outer surface is in apposition with the adi- 
 pose tissue contained in the ischio-rectal fossa. It closes the 
 anus and at the same time slightly elevates it ; it also assists 
 the transversi perinei in fixing the perineal centre. 
 
DISSECTION OF THE PERINEUM. 459 
 
 The COCCYG-EUS, Fig. 193 (i o), is situated between the pyri- 
 formis and the posterior border of the levator ani. It arises 
 from the spine of the ischium and from the small sacro- 
 sciatic ligament, and is inserted into the side of the coccyx 
 
 Fig. 194. 
 
 THE ARTERIES OF THE PERINEUM; ON THE RIGHT SIDE THE SUPERFICIAL ARTE- 
 RIES ARE SEEN, AND ON THE LEFT THE DEEP. 1. The penis, consisting of the corpus 
 spongiosum and corpora cavcrnosa. The cms penis on the left side is cut through. 
 2. The accelerators urinee muscles, inclosing the bulbous portion of the corpus 
 spongiosum. 3. The erector penis, spread out upon the crus penis of the right side. 
 4. The anus, surrounded by the sphincter ani muscle. 5. The rami of the ischium 
 and pubes. 6. The tuberosity of the ischium. 7. The small sacro-sciatic ligament 
 attached by its small extremity to the spine of the ischium. 8. The coccyx. 9. The 
 internal pudic artery, crossing the spine of the ischium, and entering the perineum. 
 10. Inferior hemorrhoidal branches. 11. The superficial perineal artery, giving 
 off a small branch, transverse perineal, upon the transversus perinei muscle. 12. 
 The same artery on the left side cut off. 13. The artery of thte bulb. 14. The two 
 terminal branches of the internal pudic artery; one is seen entering the divided ex- 
 tremity of the crus penis, the artery of the corpus cavernosum; the other, the dor- 
 salis penis, ascends upon the dorsum of the organ. 
 
 and the lower part of the sacrum. It is of a triangular form; 
 and its attachments are aponeurotic. Its inner and upper 
 surface corresponds to the rectum. Its action is to keep the 
 coccyx in its proper place, and to assist in forming the floor 
 of the pelvis. 
 
 The ISCHIO-EECTAL FOSSA is wedge-shaped, and is from an 
 inch and a half to two inches deep. The thin edge looks up- 
 wards and corresponds to the splitting of the pelvic fascia 
 into the levator or anal fascia on the inner side, and the 
 obturator fascia on the outer side. The base or thick edge looks 
 
460 OF THE PELVIS. 
 
 downwards, and corresponds to the integument. The inner 
 boundary is formed below by the sphincter ani and above 
 by the levator fascia, which covers the levator ani muscle; 
 while the outer boundary is formed below by the gluteus 
 maximus, and above by the obturator fascia, which covers 
 the obturator internus muscle. The anterior boundary is 
 formed by a reflection of the superficial perineal fascia up- 
 wards to join the deep perineal fascia; as the superficial 
 perineal fascia is reflected upwards it is joined to the ante- 
 rior border of both the obturator and the levator fascia. 
 Thus it will be seen that the ischio-rectal fossa is bounded 
 on three sides by fascia, especially the upper part of it. The 
 posterior boundary corresponds to the gluteus maximus and 
 coccygeus muscles, and to the sacro-sciatic ligaments and 
 foramina. 
 
 When the contents of the ischio-rectal fossa have been 
 removed and its boundaries carefully observed, the student 
 should endeavor to obtain a distinct idea of its relations to 
 the cavity of the abdomen. He should do this before he 
 has attempted to master the anatomy of that portion of the 
 perineum which belongs to the genito-urinary apparatus. 
 As the ischio-rectal fossa is now fairly exposed, a part of the 
 levator fascia should be carefully removed from the levator 
 muscle. Having done this, a portion of the muscle should 
 also be dissected away when another fascia, the pelvic, will be 
 observed. Kemove a portion of this and the sub-peritoneal 
 areolar tissue together with the peritoneum itself will be seen. 
 Thus a clear idea of what separates the abdominal cavity from 
 the ischio-rectal fossa will be obtained. It will be seen that, 
 besides the peritoneum and the sub-peritoneal areolar tissue, 
 the bowels are separated from the ischio-rectal fossa simply 
 by the levator ani muscle and the fasciae that cover its pelvic 
 and perineal surfaces. 
 
 It will now also be observed that the pelvic fascia, Fig. 
 199 (s), as it descends from the brim of the pelvis, divides 
 into three layers. These are the obturator (i s), the levator or 
 anai(i 5), and the recto-vesical (8,11). The first descends on the 
 obturator internus muscle, and is attached below to the ramus 
 and tuberosity of the ischium, and to the great sacro-sciatic 
 ligament; the second passes downwards on the perineal sur- 
 face of the levator muscle to the upper border of the sphinc- 
 ter ani, where it is frequently so thin that it hardly deserves 
 
DISSECTION OF THE PERINEUM:. 
 
 461 
 
 to be regarded as a distinct fascia ; the third one, after cover- 
 ing the pelvic surface of the levator, is reflected to the side 
 of the rectum, to the bladder, and the prostate gland. The 
 last-named fascia will be more particularly noticed at another 
 stage of the dissection. 
 
 That part of the perineum just dissected belongs essentially 
 to the lower portion of the intestinal canal ; while the part 
 that remains to be dissected belongs more particularly to the 
 genito-urinary apparatus. It must be admitted that the latter 
 is more complex and difficult to be examined than the former ; 
 and it should be remarked here that, although different fasciae 
 are spoken of, and have distinct names, they are all con- 
 tinuous with each other, and might be regarded as consti- 
 tuting a single fascia or aponeurosis. 
 
 By the different reflections and attachments of the fascias, 
 there are formed four principal cavities or pockets. Two of 
 
 Fig. 195. 
 
 THE PERINEUM, AFTER THE SKIN AND A PORTION OP THE SUPERFICIAL PERINEA*- 
 FASCIA HAVE BEEN REMOVED. , a. Superficial perineal fascia. 6. Accelerators 
 urinoe. e, c. Erectores penis, d, d. Tvansversi perinei. e. Upper point of sphinc- 
 ter ani. /,/. The edges of the glutei maximi. 1, 1. Superficial perineal arteries. 
 2, 2. Superficial perineal nerves. 
 
 39* 
 
462 OF THE PELVIS. 
 
 these have already been observed; they contain the levatores 
 ani muscles. The other two, which are situated, one above 
 and the other below the deep perineal fascia, are now to be 
 examined. The latter or lower one contains, besides some 
 fat and areolar tissue, the superficial perineal vessels and 
 nerves, the erectores penis, acceleratores urinae, and trans- 
 versi perinei muscles, and the bulb of the corpus spongio- 
 sum ; the former or superior one contains the membranous 
 portion of the urethra, including the muscles of Wilson and 
 Guthrie, the prostate gland, the neck of the bladder, and the 
 vesiculae seminales. 
 
 The lower one is formed by the deep perineal fascia 
 sending off a layer just behind the bulb of the urethra, 
 which passes backwards to the rectum and ischio-rectal 
 fossae, and then downwards, forming on each side the 
 anterior boundary of the ischio-rectal fossa by uniting with 
 the levator and obturator fasciae ; it is then reflected forwards 
 beneath the transversi perinei muscles and before the ante- 
 rior portion of the sphincter ani muscle, to be lost in the 
 scrotum and in the superficial fascia on each side of it. The 
 part which is reflected forwards is the superficial perineal 
 fascia ; it is attached, laterally, to the tuberosities and rami 
 of the ischia, and to the rami of the pubes. 
 
 To dissect this space, Fig. 196, two incisions should be made, 
 commencing at a point about two inches and a half in front of 
 the anus and extending them backwards, one to the tuberosity 
 of each ischium or near to the anterior boundary of the ischio- 
 rectal fossa. The fascia included between these two incisions 
 is to be raised and reflected backwards as far as the anus and 
 the ischio-rectal fossae, but not detached until its connection 
 with the deep perineal fascia has been examined ; this cannot 
 be done until the contents of the space inclosed by it and the 
 deep fascia have been dissected. The remaining portions of 
 the fascia are to be reflected laterally, and their attachments 
 to the rami of the ischia and pubes observed. The super- 
 ficial and transverse perineal vessels and nerves should now 
 bs examined. 
 
 The superficial perineal artery, Fig. 194 (i i ), enters this space 
 just below the transversus perinei muscle, and passes for- 
 wards along the inner border of the erector penis muscle. It 
 is distributed to the perineum and scrotum. 
 
 The transverse per meal artery. Fig. 194 (i i), arises sometimes 
 
DISSECTION OF THE PEKINEUM. 463 
 
 from the internal pudic, and sometimes from the preceding 
 artery. It accompanies the transversus perinei muscle to the 
 
 Fig. 196. 
 
 THE STRUCTURES CONTAINED BETWEEN THE TWO LAYERS OP THE DEEP PERINEA^ 
 FASCIA. 1. The symphysis pubis. 2, 2. The rarai of the pubes and ischia. 3, 3. 
 The tuberosities of the ischia. 4. A triangular portion of the superficial fascia 
 turned down, and shown to be continuous with the deep fascia (6, 6, 6). 5, 5. Two 
 portions of the superficial perineal fascia reflected laterally, showing its connec- 
 tion to the raini of the pubes and ischia. 6, 6, 6. The posterior layer of the deep 
 perineal fascia, the anterior layer having been removed. 7. The membranous por- 
 tion of the urethra cut across. 8. The superior fasciculus of the compressor urethrae 
 muscle of one side. 9. The inferior layer of the compressor urethrae. The two 
 fasciculi (8) and (9) constitute Guthrie's muscle of one side. 10. The pubic por- 
 tions of the comprepsores urethrae, or Wilson's muscles. 11. Cowper's glands, partly 
 embraced by the inferior layer of the compressor urethrse muscle. 12. The internal 
 pudic artery passing anteriorly to the origin of the compressor urethrae. 13. The 
 artery of the bulb. 14. The artery of the corpus cavernosum. 15. The arteria 
 dorsalis penis. 
 
 perineal centre, supplying the integument and muscles in 
 front of the anus. The direction of this artery should be 
 particularly observed. 
 
 The nerves have the same course and distribution as the 
 arteries, which they for the most part accompany. 
 
 After removing the vessels and nerves just examined, and 
 also the adipose substance and areolar tissue, of which a con- 
 siderable quantity is usually found in this space, the follow- 
 ing muscles will be exposed and should be carefully studied. 
 A thin aponeurotic fascia, which must not be confounded 
 with the superficial perineal fascia, will be found investing 
 
464 OF THE PELVIS. 
 
 and forming for each of them a sheath; it is connected pos- 
 teriorly with the deep perineal fascia. 
 
 The ERECTOR PENIS, Fig. 193 (e), occupies the outer por- 
 tion of the space.* It arises, tendinous and fleshy, from the 
 tuberosity and ramus of the ischium and the ramus of the 
 pubes, passes upwards and forwards, and is inserted into the 
 corresponding crus of the penis. It draws the crus down- 
 wards and backwards, and probably facilitates the erection 
 of the penis. 
 
 The ACCELERATOR URIN^E, Fig. 193 (5), is situated to the 
 inner side of the preceding muscle. It arises from the peri- 
 neal centre, and from the raphe which extends forwards in 
 the median line from the centre. Its posterior fibres pass 
 upwards and forwards, embracing the bulb, and are inserted 
 into the deep perineal fascia; the middle are inserted into a 
 thin tendon above the urethra which is common to the ac- 
 celeratores muscles; and the anterior fibres terminate in a ten- 
 dinous expansion on the side and dorsum of the penis. Its 
 action is to compress the urethra. 
 
 The TRANSVERSUS PERINEI, Fig. 193 (7), is a small muscle 
 which arises from the inner side of the tuberosity of the 
 ischium, near the commencement of the origin of the erector 
 penis, and is inserted into the perineal centre. It is frequently 
 absent. Its action is to assist in keeping the centre of the 
 perineum fixed ; and it may, from the direction of its fibres, 
 tend to draw it slightly upwards and backwards. A fasci- 
 culus of fibres is sometimes met with here which has been 
 denominated the transversus perinei alter. When present, 
 this small muscle is usually situated deeper than the trans- 
 versus perinei, being covered in by a thin layer of the 
 deep perineal fascia. It arises from the rami of the ischium 
 and pubes, and is inserted into the side of the bulb. It is not 
 unusual to find irregular fasciculi of fibres in this space ; 
 sometimes apparently belonging to the transversus perinei, 
 and again to the accelerator urinae, or levator ani. 
 
 These muscles may now be raised, but not detached so 
 that they cannot be replaced and viewed with reference to 
 cutting down upon the membranous portion of the urethra. 
 The bulb of the corpus spongiosum should be carefully 
 separated from the perineal centre without destroying the 
 deep perineal fascia at this point. A triangular space will 
 
DISSECTION OF THE PEKINEUM. 
 
 465 
 
 be observed on each side of the bulb, at the bottom of which 
 the triangular ligament or deep perineal fascia will be dis- 
 tinctly seen ; by seizing hold of that portion of the super- 
 ficial perineal fascia which was reflected backwards, and 
 making it tense, its connection with the deep fascia will be 
 made clear. The tendency of urine when it has escaped from 
 the urethra into this space, to pass forwards into the scrotum 
 instead of passing backwards into the ischio-rectal fossaB, will 
 now appear evident. 
 
 The artery of the bulb, Fig. 194 (i 3), should now be sought. 
 It arises from the internal pudic between the two layers of the 
 
 Fig. 197. 
 
 A DEEPER DISSECTION THAN THAT REPRESENTED IN FIG. 195, THE PERINEAL 
 MUSCLES BEING REMOVED AND ALSO THE FAT IN THE ISCHIO-RECTAL FOSS.E. a, a. 
 Superficial perineal fascia. 6. Accelerators urinae. c, c. Crura penis, d. The 
 bulb. e. Deep perineal fascia. /,/. Levatores ani, and inferior hemorrhoidal arte- 
 ries and nerves, g. Sphincter ani. h, h. Tuberosities of ischia. k, k. Glutei inax- 
 irai. *. Cowper's gland of the left side, and the artery of the bulb just in front 
 of it. 1. Internal pudic artery. 2, 2. Superficial perineal arteries and nerves. 
 
 deep fascia at a point nearly opposite to the bulb. It is rea- 
 dily found by cautiously dividing the layer that covers it at 
 the inner side of the corresponding crus penis and reflecting 
 
466 OF THE PELVIS. 
 
 it to the bulb. The internal pudic itself may be exposed at 
 the same time in this part of its course ; it is partly con- 
 cealed by the crus, and the ramus of the ischiuni. The 
 artery of the bulb is distributed to the corpus spongiosum, 
 being directed, after entering it from behind forwards. 
 It will now be seen that this artery, together with the 
 transverse perineal and the inferior hemorrhoidal, has a 
 transverse direction. The transverse perineal is necessarily 
 divided in the lateral operation for stone in the bladder, 
 while the artery of the bulb is avoided by not cutting too 
 far forwards, and the hemorrhoidal by not extending the 
 incision too far backwards in the ischio-rectal fossa. The 
 superficial perineal artery may or may not be cut in this 
 operation. The position of the internal pudic may be noticed 
 at this time with reference to the same operation. It will be 
 observed that it lies on the outside of both the ischio-rectal 
 fossa and the triangular space between the bulb and the crus 
 penis, so that, occupying its normal position, it should never 
 be cut in entering the bladder through the perineum. 
 
 The arteries of this region are subject to variations as they 
 are in every other part of the body. Instead of one there 
 may be two arteries of the bulb ; or this artery may be a 
 branch of some other than the internal pudic. There may 
 be several hemorrhoidal branches, when the one situated 
 anteriorly would almost necessarily be cut in the lateral 
 operation for stone. 
 
 The GLANDS OF COWPER, Fig. 197 (*), should now be ex- 
 amined. There are two of them. They are situated, each 
 one just behind and a little below the bulb, being inclined 
 a little to the side of it. Each is about the size of a pea, 
 although they vary much in this respect. They have no 
 proper capsules, but are placed between the two layers of the 
 deep perineal fascia. They will be found by extending the 
 dissection that was made for exposing the artery of the bulb 
 a little deeper and further backwards. They are usually 
 covered below by some fibres belonging to the muscles of 
 Guthrie. Their excretory ducts open into the urethra, as 
 was mentioned in the description of that organ. The student 
 should not be discouraged if he does not find them in his 
 first dissection of these parts. A third gland, situated below 
 the arch of the pubes, and close to Cowper's glands, has been 
 
DISSECTION OF THE PEKINEUM. 467 
 
 described, and called the gland of Litre, and named by Litre 
 the anti-prostatic gland. 
 
 Before proceeding to dissect the upper cavity or pocket, it 
 will be well to examine the deep perineal fascia, immediately 
 below the arch of the pubes, and also the levator ani muscle. 
 The first may be done by dividing the corpus spongiosum 
 and the urethra about an inch anterior to the bulb, and 
 dissecting them up as far back as the point where the urethra 
 perforates the fascia. A catheter or bougie should be intro- 
 duced into the urethra where it has been divided, and carried 
 into the bladder. When this is done, the deep perineal fascia 
 will be seen attached above to the symphysis pubis, laterally 
 to the rami of the pubes ; and below, it will be seen perfo- 
 rated by the membranous portion of the urethra. From its 
 shape and structure it has been called the triangular liga- 
 ment. It consists of two layers, separated by the sub-pubic 
 ligament. Only one of these can now be seen. By means 
 of this dense fibrous membrane the urethra, which perforates 
 it about three-fourths of an inch below the symphysis pubis, 
 is at this point firmly fixed in its position. This fact should 
 be carefully observed with reference to the introduction of 
 instruments through the urethra into the bladder. 
 
 Before examining the levator ani muscle, the continuity of 
 the deep perineal fascia with the superficial perineal, the ob- 
 turator, and the levator fasciae should be attentively studied ; 
 also its connection with the perineal centre. Thus far in the 
 dissection no part of these fasciae has been cut away or de- 
 stroyed so as to prevent a review of them being made, 
 which is essential to a thorough understanding of them. To 
 examine the levator ani muscle, the lower part of the rectum 
 should be slightly drawn down and pushed to one side, while 
 some portions of the fasciae just alluded to, including the 
 whole of the levator, must be removed. 
 
 The LEVATOR ANI, Fig. 193 (9), is a thin, broad muscle, 
 placed on the side of the lower part of the rectum. Its 
 origin, commencing at the symphysis pubis, extends back- 
 wards across the obturator foramen to the spine of the 
 ischium. Anteriorly, it arises from the symphysis pubis and 
 from the body of the pubes; posteriorly, from the body and 
 spine of the ischium ; the part of the muscle which corre- 
 sponds to the foramen, arises from the pelvic fascia, where it 
 
468 OF THE PELVIS. 
 
 splits to form the levator and recto-vesical fasciae; a white 
 line may be seen from the inside of the pelvis corresponding 
 to this line of separation. As the fibres descend, the entire 
 muscle is inclined obliquely inwards, towards the median 
 line of the perineum. The insertion of its fibres extends from 
 the coccyx behind, to the perineal centre in front. Those in 
 the middle part are inserted into the external sphincter 
 and lower part of the rectum; the posterior fibres into the 
 coccyx and a raphe' extending from the coccyx to the anus ; 
 and the anterior fibres into the perineal centre and the rec- 
 tum behind the bulb of the urethra. From the origin and 
 insertion of this muscle, it will be seen that its pelvic surface 
 corresponds to the prostate gland, the neck and lower fundus 
 of the bladder, the vesiculse seminales, and the lower part of 
 the rectum ; and that, when both of the muscles act together, 
 they tend to elevate, and at the same time compress, these 
 organs; and, hence, they co-operate with the abdominal 
 muscles in the evacuation of the fseces, the urine, and the 
 contents of the seminal vesicles. 
 
 The upper cavity or pocket is formed by a reflection of the 
 two layers of the deep perineal fascia upwards to join the 
 pelvic fascia on the prostate gland and vesiculae seminales. 
 The muscles of Wilson and Guthrie, or the compressores 
 urethra, are placed between these two layers so as to inclose 
 the membranous portion of the urethra. These two layers 
 of fascia will be better understood when the muscles just 
 mentioned have been described. 
 
 The COMPKESSOKES, or LEVATOKES UKETHK^E, Fig. 196 
 
 (s, 9, i o), are composed of two sets of fibres. Those which 
 compose the muscle of Guthrie arise on each side by a short 
 tendon from the ramus of the ischium near where it joins 
 the ramus of the pubes, and, passing transversely inwards, 
 divide into two layers, each of which is inserted into a raphe', 
 the one above and the other below the membranous portion 
 of the urethra, extending from the bulb to the prostate gland. 
 Those described by Wilson form on each side a small fas- 
 ciculus, which arises by a narrow tendon from the back part 
 of the symphysis pubis about midway between the anterior 
 ligaments of the bladder and the pubic arch, and, passing 
 downwards, is inserted into the muscle of Guthrie. Both of 
 these muscles are fan-shaped, being broader at their insertion 
 
DISSECTION OF THE PERINEUM. 469 
 
 than at their origin. Their fibres are so intermixed with 
 spongy tissue, adipose substance, and bloodvessels, that it is 
 often difficult to obtain a clear and satisfactory view of them ; 
 and the difficulty is not unfrequently augmented by the blood 
 that escapes from the vessels which are divided; they are 
 also very feebly developed in some subjects; so that if the 
 student does not succeed, in his first attempt to expose these 
 muscles, in getting so distinct a view of them as he might 
 expect from the description given of them in books, he should 
 not be discouraged. In the whole body there is, perhaps, no 
 other region in the dissection of which so much depends for 
 success upon the character of the subject, as the perineum. If 
 the subject be very fat, or the veins distended with blood, or 
 the muscles pale and feebly developed, it is almost impossible 
 for any one to make a satisfactory dissection or demonstra- 
 tion of the parts found in this region. As the membranous 
 portion of the urethra is placed between the two layers of 
 the muscle of Guthrie, it will be compressed when that muscle 
 contracts ; it may also be drawn downwards, which, however, 
 is counteracted by the action of the muscle of Wilson, which 
 tends to draw it upwards. The action of the latter seems to 
 be in part to steady the former. The glands of Cowper are 
 compressed by the lower fibres of the muscles of Guthrie. 
 A thin layer of fascia will be found separating the posterior 
 fibres of the muscle of Guthrie from the anterior fibres of the 
 levator ani. This intermediate fascia is best observed by 
 carefully removing the anterior fasciculi of the levator before 
 the muscle of Guthrie has been disturbed. Like all other 
 intermuscular septa or sheaths of muscles, it varies very 
 much in thickness in different subjects. 
 
 Besides the compressores urethras muscles there will be 
 found surrounding the membranous portion of the urethra 
 an erectile, elastic fibrous tissue, also several veins or a plexus 
 of veins. The dorsal veins of the penis, after perforating the 
 sub-pubic ligament and deep perineal fascia, pass through 
 this region close to the arch of the pubes, Fig. 198 (14), to 
 reach the vesico-prostatic plexus of veins. 
 
 Before proceeding further with the dissection upwards, 
 the upper surface of the pelvic fascia must be exposed by the 
 removal of the peritoneum and the subperitoneal areolar 
 tissue ; which can be done by partly tearing and partly dis- 
 secting them oft'. That portion of the pelvic fascia which 
 40 
 
470 OF THE PELVIS. 
 
 corresponds to the ischio-rectal fossa was noticed in the 
 examination of that fossa. It was then seen how the levator 
 and obturator fascias joined the pelvic ; it now remains to be 
 
 Fig. 198. 
 
 A SIDE VIEW OP THE VISCERA OP THE PELVIS, SHOWING THE DISTRIBUTION OP 
 THE PERINEAL AND PELVIC FASCIAE. 1. The symphysis pubis. 2. The bladder. 
 3, 3. The recto-vesical fold of peritoneum, passing from the anterior surface of the 
 rectum to the posterior part of the bladder; from the upper part of the fundus of 
 the bladder it is reflected upon the abdominal parietes. 4. The ureter. 5. The 
 vas deferens crossing the direction of the ureter. 6. The vesicula seminalis of the 
 right side. 7, 7. The prostate gland. 8, 8. The section of a ring of elastic tissue 
 encircling the prostatic portion of the urethra at its commencement. 9. The pros- 
 tatic portion of the urethra. 10. The membranous portion, inclosed by the com- 
 pressor urethrse muscle. 11. The commencement of the corpus spongiosum penis, 
 the bulb. 12. The anterior ligaments of the bladder. 13. The edge of the pelvic 
 fascia at the point where it is reflected upon the rectum. 14. An interval between 
 the pelvic fascia and deep perineal fascia, occupied by a plexus of veins. 15. The 
 deep perineal fascia; its two layers. 16. Cowper's gland of the right side. 17. 
 The superficial perineal fascia, ascending in front of the root of the penis to become 
 continuous with the dartos of the scrotum (18). 19. The layer of the deep fascia 
 which is prolonged to the rectum. 20. The lower part of the levator ani; its fibres 
 are concealed by the anal fascia. 21. The inferior segment of the funnel-shaped 
 process given oif from the posterior layer of the deep perinenl fascia, which is 
 continuous with the recto-vesical fascia of Tyrrell. The attachment of this fascia 
 to the recto-vesical fold of peritoneum is seen at 22. 
 
 noticed, in the first place, how the two layers of the deep 
 perineal fascia, which are placed, as has been seen, the one 
 above and the other below the muscles of Guthrie, in- 
 cluding also the membranous portion of the urethra, join 
 the pelvic fascia. This junction takes place around the neck 
 of the bladder, and usually on the sides of the prostate gland 
 just below the neck. If we examine the layer placed above 
 the muscles, we shall find that it joins the pelvic fascia 
 
DISSECTION OF THE PERINEUM. 471 
 
 through the medium of the anterior ligaments of the bladder, 
 which may be regarded as portions of the pelvic fascia. 
 The layer which is placed below the same muscles, after 
 covering their under surface, is reflected to the sides of the 
 prostate gland and the neck of the bladder, where it joins 
 the pelvic fascia just behind the anterior ligaments of the 
 bladder; so that we find three fascise or layers of fascia, 
 uniting on the sides of the prostate and the fore part of the 
 neck of the bladder, forming a conjoined fascia of the pelvic 
 and deep perineal fascice. The lower layer of the deep pe- 
 rineal fascia is not only reflected over the sides of the pros- 
 tate, but passes upwards over its lower surface, and also 
 over the vesiculae seminales so as to inclose them. 
 
 Fig. 199. 
 
 A TRANSVERSE VERTICAL SECTION OP THE PELVIS, SHOWING THE DISTRIBUTION 
 OF THE PELVIC FASCIA. 1. The bladder. 2. The vesicula seminalis of one side, 
 divided across. 3. The rectum. 4. The iliac fascia, covering in the iliacus and 
 psoas muscles (5), and forming a sheath for the external iliac vessels (6). 7. The 
 anterior crural nerve, excluded from the sheath. 8. The pelvic fascia. 9. Its as- 
 cending layer, forming the lateral ligament of the bladder of one side, and a sheath 
 to the vesical plexus of veins. 10. The recto-vesical fascia of Tyrrell, formed 
 by the middle layer. 11. The inferior layer surrounding the rectum and meeting at 
 the middle line with the fascia of the opposite side. 12. The levator ani muscle. 
 13. The obturator internus muscle, covered in by the obturator fascia, which also 
 forms a sheath for the internal pudic vessels and nerve (14). 15. The layer of 
 fascia which invests the under surface of the levator ani muscle, the anal fascia. 
 
 The junction of the deep perineal and pelvic fascias 
 around the prostate gland and neck of the bladder is very 
 important when viewed with reference to cutting into the 
 bladder through the perineum. It is by means of this con- 
 
472 OF THE PELVIS. 
 
 nection that the cavity of the abdomen is protected against 
 effusions of urine in cutting for stone. The pelvic fascia, 
 where it is reflected from the parietes of the pelvis to join 
 the deep perineal on the sides of the prostate gland and neck 
 of the bladder, forms, together with this fascia, a complete 
 septum between the abdominal cavity and the space in which 
 the incision is made in cutting for stone. The pelvic fascia 
 may join the deep perineal so low down as to leave hardly 
 space sufficient for making the necessary incision without 
 wounding the fascia where it is covered by peritoneum. We 
 have seen one instance in which it appeared to us that it 
 would be almost impossible to avoid wounding the perito- 
 neum in making an incision sufficiently large to remove an 
 ordinary sized calculus. The higher up the junction be- 
 tween the pelvic and deep perineal fasciae takes place, the 
 less danger there will be of injury being done to the perito- 
 neum. What are sometimes called the lateral ligaments of 
 the bladder are those portions of the pelvic fascia which 
 are reflected from the walls of the pelvis to the sides of 
 the neck of the bladder. They are placed just behind the 
 anterior ligaments. All the fasciae, or the different layers of 
 fasciae belonging to the genito-urinary apparatus, and several 
 connected with the lower part of the alimentary canal having 
 now been examined, it will be observed that these fasciae are 
 not only continuous with each other, but they can be traced 
 from the pelvic fascia commencing above just as well as from 
 the triangular ligament or deep perineal fascia commencing 
 below ; and this should be done by the student. 
 
 Commencing with the pelvic fascia and tracing it down- 
 wards from its origin at the brim of the pelvis, the student, 
 after having dissected the perineum and studied the pelvic 
 viscera, will have little or no difficulty in understanding its 
 connections with other fasciae, and its relations to the pelvic 
 organs. Anteriorly he will observe the manner in which it 
 is reflected to the neck of the bladder, and to the sides of the 
 prostate gland, forming the anterior and lateral ligaments of 
 the bladder, and also a sheath for the anterior portion of the 
 vesical plexus of veins; also the manner in which it is con- 
 tinuous downwards and forwards with the layers of the deep 
 perineal fascia, as they are placed, one above and the other 
 below the muscles of Wilson and Guthrie. When the at- 
 tachments of the deep perineal fascia to the arch of the 
 
DISSECTION OF THE PERINEUM. 473 
 
 pubes and the rami of the ischia, and of the pelvic fascia to the 
 brim of the pelvis, and then the manner in which these fasciae 
 are joined to each other and are connected with the neck of 
 the bladder, the prostate gland, and the membranous portion 
 of the urethra, are observed, it would seem to be impossible 
 for any displacement of these organs to occur. In tracing 
 the middle portion of the pelvic fascia, it will be observed 
 that it is reflected between the rectum and bladder to join the 
 fascia of the opposite side, thus forming what is called the 
 recto-vesical fascia, Fig. 199 (10), and behind this, to the sides 
 of the rectum, in the same way as it was anteriorly to the 
 neck of the bladder. The recto-vesical fascia has been called 
 the fascia of Tyrrell. It is reflected upwards on the bladder 
 in front, and on the rectum behind, becoming more and 
 more attenuated until it disappears on the parietes of these 
 organs. As it is reflected on the bladder it splits to form a 
 sheath for the posterior part of the vesical plexus of veins, 
 Fig. 199 (9). Below, it is joined by the deep perineal fascia 
 which is continued up behind the prostate gland and the 
 vesiculas seminales, splitting to form a sheath for the last 
 named bodies, Fig. 199 (2). Where the pelvic fascia is re- 
 flected to the rectum, a layer proceeds downwards as far as 
 the insertion of the levator ani muscle, separating this mus- 
 cle from the rectum ; this is continuous anteriorly with the 
 deep perineal fascia behind the prostate gland and vesiculaa 
 seminales. 
 
 As the anterior part of the pelvic fascia is continuous 
 with two layers which belong to the perineum, so is the 
 middle portion of it; these are the levator and obturator 
 fascias. The levator fascia is given off from the obturator 
 rather than from the pelvic fascia ; the continuity, however, 
 remains the same. A line having an antero-posterior direc- 
 tion is observed at or just above the origin of the levator 
 fascia ; it is caused by a thickening of the fascia, and gives 
 strength to the upper attachment of the middle portion of 
 the levator ani muscle. When it is remembered that the 
 levator and obturator fasciae are connected to the layer which 
 joins the deep with the superficial perineal fascia in front of 
 the ischio-rectal fossa, the connection of the two last-named 
 fascise with the middle portion of the pelvic fascia will be 
 readily seen. 
 
 The posterior part of the pelvic fascia passes behind the 
 
474 FEMALE OKGANS OF GENERATION. 
 
 rectum, dividing into two layers ; one for the rectum, which 
 is continuous anteriorly with the layers given off from the 
 middle part of the pelvic fascia ; the other passes between 
 the sacral plexus of nerves and the branches of the internal 
 iliac vessels, which appear to be furnished with sheaths from 
 this fascia ; it is finally lost in dense areolar tissue on the an- 
 terior surface of the sacrum. Between the coccygeus and 
 the levator ani muscles the levator fascia is joined to the 
 pelvic by a thin lamina, thus completing the cavity which 
 contains the levator ani muscle. 
 
 From the arrangement of the fasciae or aponeuroses in the 
 perineum and pelvis, the term perineo-pelvic fascia might with 
 propriety be applied to them generally. It may be observed 
 that the fascia which arises from the anterior and lateral 
 portions of the brim of the pelvis is continuous all around 
 with those which have their origin from the borders of the 
 lower strait of the pelvis, and that in passing from one 
 border to the other they inclose certain organs so as to keep 
 them in situ, or they send off processes which are attached 
 to the organs contained in the central part of the pelvis. 
 
 SECT. IV. DISSECTION OF THE FEMALE ORGANS OF 
 GENERATION. 
 
 The genital organs in the female differ so essentially 
 from the corresponding ones in the male, that a separate 
 examination of them is necessary. It is of the utmost im- 
 portance that the student, before he commences this dissection, 
 should make himself familiar with the appearance of all the 
 parts within the reach of inspection. The vagina should be 
 carefully cleansed by means of a syringe, and afterwards the 
 finger should be introduced into it, for the purpose of touch- 
 ing the os tincse in situ, of ascertaining its distance from the 
 exernal orifice of the vagina, and how far the finger must be 
 introduced in order to reach it, so as to be able to judge fairly 
 of its condition. This should be practised after the cavity 
 of the abdomen has been opened, so that the relations of the 
 vagina to that cavity may be observed. The relation that 
 exists between the vagina and the peritoneum is exceedingly 
 important ; every student should observe this for himself. 
 The introduction of the speculum into the vagina, and of a 
 
FEMALE ORGANS OF GENERATION. 475 
 
 probe or bougie into the os uteri, may be practised in the 
 dissecting-room to considerable advantage. It is, perhaps, 
 equally important to become familiar with the parts involved 
 in carrying an instrument through the urethra into the blad- 
 der. The student should observe for himself what points he 
 could rely on to guide him in conducting the catheter to the 
 meatus urinarius, and thence into the bladder. It has happened 
 that through the neglect of acquiring the necessary familiarity 
 with the exact position of the external orifice of the urethra, 
 and its relations to the surrounding parts, the young phy- 
 sician has been subjected to feelings of chagrin and mortifi- 
 cation, in consequence of his having failed to introduce the 
 catheter the first time he attempted it in his practice; or 
 if he has not failed, he has been compelled to make an im- 
 proper exposure of the person of his patient in order to 
 succeed. One or two hours devoted to the examination of 
 these parts, and to the practice of introducing the catheter, 
 in the dissecting-room, will be worth more than all that can 
 be learned from reading books on this subject. 
 
 The female organs of generation are divided into the 
 external and internal. In the latter are included the uterus, 
 the ovaries, and the Fallopian tubes; in the former, the vagina 
 and the parts that constitute the VULVA, which are the mons 
 veneris, the labia majora and minora, the anterior and posterior 
 commissures, the fourchette, the fossa navicularis, the clitoris, 
 the vestibule, the meatus urinarius, the hymen, and the carun- 
 culce myrtiformes. All these parts should be carefully in- 
 spected in situ. 
 
 The MONS YENERIS, Fig. 200 (3), is an eminence placed 
 in front of the symphysis pubis and the pubic bones. It is 
 formed by areolar tissue and adipose substance, situated be- 
 neath the integument, which in adult life is covered with hair. 
 
 The LABIA MAJORA, Fig. 200 (i, i), are situated below the 
 mons veneris, one on each side of the rima, or the fissure 
 that leads to the vagina. Each consists of a fold of the 
 integument, which contains a substance resembling the dar- 
 tos in the male, areolar tissue and fat, besides vessels, nerves 
 and sebaceous follicles. Its free border is round, and thicker 
 than its attached border; it is also thicker above than be- 
 low. Its external surface is continuous with the skin and 
 covered with hair, while its internal surface is continuous 
 
476 FEMALE ORGANS OF GENERATION. 
 
 with the mucous membrane of the vagina, so that the skin 
 blends with the mucous membrane on its free border. The 
 rima or opening between them has an elliptical form. The 
 labia become exceedingly attenuated during parturition, but 
 very soon recover their natural form and condition. From 
 the quantity of loose areolar tissue which they contain, they 
 are very liable to serous infiltration. 
 
 The ANTERIOR and POSTERIOR COMMISSURES are situated, 
 the former at the anterior junction of the labia majores, and 
 the latter, Fig. 201 (e), at their posterior junction. They are 
 merely the extremities of the rima vulva3. 
 
 The FOURCHETTE or FR^NULUM LABIORUM, Fig. 200 (2), 
 is a small duplicature of the mucous membrane placed a 
 
 Fig. 200. 
 
 A VIEW OF THE EXTERNAL ORGANS or GENERATION IN THE VIRGIN THE VULVA 
 BEING PARTIALLY OPEN. 1, 1. Labia majora. 2. Fourchette. 3. Mons veneris. 
 4. Prepuce of the clitoris around the glans clitoridis. 5. Vestibule. 6, 6. The 
 nymphae. 7, 8. The hymen, open in its central portion and surrounding the infe- 
 rior extremity of the vagina. 9. The perineum. 10. The anus. 
 
 short distance behind the posterior commissure. It is fre- 
 quently lacerated and destroyed during the first parturition. 
 
 The FOSSA NAVICULARIS is a small depression situated 
 between the posterior commissure and the fourchette. 
 
 The LABIA MINORA or NYMPHS, Fig. 200 (e,e), are folds 
 of the mucous membrane placed within the labia majora. 
 If they be traced from below, they will be found to com- 
 mence, one on each side, near the middle of the junction 
 
FEMALE ORGANS OF GENERATION. 477 
 
 of the labia majora with the vagina and to extend upwards, 
 gradually increasing in size and approaching each other. 
 About three-fourths of an inch below the anterior com- 
 missure each one bifurcates, or divides into two folds, an 
 upper and a lower, which unite in the median line with 
 those of the opposite side. The duplicature formed by the 
 junction of the two upper folds constitutes the preputium 
 clitoridis, Fig. 200 (4), while that formed by the two lower 
 joins the glans clitoridis, or the anterior and lower part of 
 the clitoris; it seems to correspond to the frasnum of the pre- 
 puce of the penis. The nymphse vary very much in size in 
 different persons; sometimes they are seen projecting beyond 
 the labia majora, and then again they are so small that they 
 can hardly be recognized as distinct bodies. They contain 
 numerous small sebaceous follicles. 
 
 The CLITORIS, Fig. 203 (7), corresponds to the penis in the 
 male. It is placed below and in front of the symphysis 
 pubis between the labia majora and above the urethra. It 
 resembles somewhat in its formation the penis. It has two 
 corpora cavernosa, which are connected by their crura to the 
 rami of the ischia and pubes. It has no corpus spongiosum 
 although it has a glans, which is situated on the anterior ex- 
 tremities of the corpora cavernosa ; it is composed of erectile 
 tissue. 
 
 The corpora cavernosa are formed, nearly of the same tis- 
 sues as the corresponding bodies in the penis. Each crus 
 has a muscle resembling in its origin and insertion the erec- 
 tor penis. It is called the erector clitoridis, Fig. 203 (e). The 
 clitoris, also, has a suspensory ligament. The clitoris, like 
 the nymphas, varies greatly in size. It is said to have be- 
 come very much enlarged under the influence of certain 
 habits, such as constant titillation. 
 
 The VESTIBULE, Fig. 200 (s), is a smooth triangular 
 surface, bounded laterally by the nymphs, below by the 
 meatus urinarius, and above by the inferior folds of the 
 nymphae. This space should be observed with reference to 
 the introduction of the catheter; for when this surface is 
 found, there will usually be but little difficulty in determin- 
 ing the exact position of the orifice of the urethra. 
 
 The MEATUS URINARIUS, Fig. 205 (7), or external orifice of 
 
478 FEMALE ORGANS OF GENERATION. 
 
 the urethra is situated in the median line and midway between 
 the nymphae and just above the upper projecting edge of the 
 vagina. It is surrounded by a slight elevation or ridge 
 formed by the mucous membrane, and, beneath this, by a 
 band of fibres which cause a slight constriction. It is gene- 
 rally closed. 
 
 The HYMEN, Fig. 200 (7,8), consists of a fold of mucous 
 membrane placed at the entrance of the vagina. It varies in 
 shape, being sometimes crescentic with the concavity looking 
 upwards ; and, again, consisting of a transverse band with an 
 opening above and below it ; or it may form a ring having 
 an opening in the centre with a fringed margin. It may en- 
 tirely close the external orifice of the vagina so as to prevent 
 the escape of the menstrual discharge. It is very rarely met 
 with in the dissecting-room. Its absence does not afford any 
 certain evidence of the loss of virginity. 
 
 The CARUNCULJE MYRTIFORMES, Fig. 201 (2 5, 2 s), are the 
 remains of the hymen. They consist of small reddish bodies 
 attached to the sides and the lower part of the opening into 
 the vagina. 
 
 VAGINA. 
 
 The VAGINA is placed between the vulva and the uterus, 
 being from four and a half to five and a half inches in length ; 
 as it is curved, with the concavity looking forwards, its pos- 
 terior wall is somewhat longer than the anterior. Its anterior 
 wall corresponds to the bladder and urethra, while the pos- 
 terior wall corresponds to the cavity of the peritoneum, the 
 rectum, and the perineum. Its axis corresponds to that of 
 the lower part of the pelvis. It is larger above than below ; 
 in this respect it is the reverse of the rectum. Its anterior 
 and posterior walls are in apposition, although in drawings 
 they are represented as separated some distance from each 
 other. The cervix of the uterus projects into it at its upper 
 extremity, the posterior lip more than the anterior. _This 
 results from its attachment to the uterus being a little higher 
 behind than before. 
 
 It is lined by a vascular mucous membrane. Transverse 
 rugce are observed on its upper and lower surfaces. These 
 do not, like the rugsa of mucous membranes generally, disap- 
 
VAGINA. 479 
 
 pear when the organ is distended. They are more numerous 
 on the superior than the inferior wall, and are more distinct 
 in the infant than in the adult. There is a longitudinal ridge 
 
 Fig. 201. 
 
 VIEW OF THE UTERUS, OVARIES, FALLOPIAN TUBES, HOUND LIGAMENTS, VA- 
 GINA AND VULVA 1. Anterior face of the uterus covered by the peritoneum. 2. 
 Its fundus. 3. One of its superior lateral angles near the origin of the Fallopian 
 tubes. 4. Side of the uterus. 5, 5. Its neck embraced by the upper end of the 
 vagina. 6, 6, 6, 6, 6. The broad ligaments. 7, 7. The ovaries drawn up by hooks 
 above their natural position. 8, 8. The ligaments which unite the ovaries to the 
 uterus. 9, 9. Fallopian tubes. 10, 10. Enlargement near their extremities. 11, 11. 
 Their trumpet-shaped mouths. 12, 12. The pavilions. 13, 13, 13, 13. Corpora fim- 
 briata. 14, 14. Portions of the fimbriated processes running to the ovaries. 15. 
 Section of one of the round ligaments. 16, 16, 16, 16. A longitudinal section of 
 the vagina. 17, 17. External surface of the vagina. 18, 18. Its internal anterior 
 parietes. 19. Longitudinal lines forming a sort of raph6 on its posterior wall. 
 20, 20. Transverse wrinkles or folds. 21. Anterior lip of the os uteri. 22. Its pos- 
 terior lip. 23. Os uteri externum. 24. Perineum. 25, 25. Carunculsa myrtiforraes 
 drawn out. 26. Posterior commissure of the vulva forcibly drawn out. 27. The 
 anus. 28. Labium majus everted. 29, 29. The two halves of the clitoris and the 
 labia minora forcibly separated. The rectum, cut off and tied, is seen behind; the 
 bladder and other parts have been removed in front. 
 
 in the median line of both the upper and the lower wall. 
 These are named the columns of the vagina, Fig. 201 (19). 
 The mucous membrane is covered by a squamous epithelium. 
 It contains numerous follicles and papillae, especially near its 
 external orifice. It is continued into the uterus above, and 
 
480 FEMALE ORGANS OF GENERATION. 
 
 prolonged downwards to be lost in the skin on the labia 
 majora. 
 
 Besides the mucous membrane the walls of the vagina 
 contain a layer of erectile tissue inclosed in two quite thick 
 
 Fig. 202. 
 
 FRONT VIEW OF THE ERECTILE STRUCTURES OF THE EXTERNAL ORGANS OF GENE- 
 RATION IN THE FEMALE. a. Bulbus vestibuli. 6. Sphincter vaginae muscle, e, e. 
 Venous plexus. /. Glans of the clitoris, g. Connecting veins, h. Dorsal vein of 
 the clitoris, k. Veins going beneath pubes. L The obturator vein. 
 
 layers of fibrous structure, and outside of these a layer 
 similar to the dartos in the scrotum of the male. The erec- 
 tile tissue is more abundant near the external orifice than 
 above near the uterus. The lulbi vestibuli, Fig. 202 (a), are 
 situated, one on each side, at the lower part of the vagina, 
 between it and the nymphae and vestibule. They are sup- 
 posed to be analogous to the bulb of the corpus spongiosum 
 of the penis. Each is about an inch in length. They are 
 covered by the mucous membrane. 
 
 The anterior wall is thicker than the posterior, especially 
 in the median line, where the urethra is imbedded in it. 
 The peritoneum descends between the rectum and vagina, 
 Fig. 205, so as to cover about one-fourth of the posterior wall 
 of the latter organ. The parietes of the vagina are very 
 
VAGINA. 481 
 
 distensible, as is shown in parturition. A part of the fibres 
 of the levatores ani muscles, Fig. 203 (4), are spread out on 
 the sides of the vagina. 
 
 The SPHINCTER VAGINAE MUSCLE, Fig. 203 (2), surrounds 
 the vagina close to its external orifice. It is exposed by re- 
 moving the integument from the perineum and labia majora. 
 Its fibres arise from the centre of the perineum, and, passing 
 upwards and forwards on the sides of the vagina, are inserted 
 into the corpora cavernosa of the clitoris, some fibres passing 
 on to the suspensory ligament. This muscle is narrow at its 
 origin and insertion, but spreads out on the parietes of the 
 vagina. It corresponds to the ejaculator urinag in the penis. 
 Its action is to constrict the anterior orifice of the vagina. It 
 also compresses the glands of Bartholine or the vulva-vaginal 
 glands, two small bodies situated, one on each side, between 
 
 Fig. 203. 
 
 A VIEW OF THE MUSCLES OF THE PERINEUM IN THE FEMALE. 1. Tuber iscbii. 2. 
 Sphincter vaginae. 3,3. Its insertion into the clitoris. 4. Vaginal ring of the same 
 muscle, which receives a part of the fibres of the levator ani. 5. Intercrossing of 
 the sphincter ani and sphincter vaginae muscles at the perineal centre. 6. Erector 
 clitoridis. 7. The clitoris, covered by its prepuce. 8. Transversus perinei muscle. 
 9. Sphincter ani. 10. Levator ani. 11. The gracilis. 12. Adductor magnus. 13. 
 Posterior part of the gluteus inaximus. 
 
 41 
 
482 FEMALE ORGANS OF GENERATION. 
 
 the vagina and the erector clitoridis. They open by small 
 ducts, about half an inch in length, close to the lateral and 
 posterior caruncula3, by which they are usually concealed. 
 
 The vulva is supplied with arteries derived principally 
 from the internal and external pudic. The vagina receives 
 branches from the internal pudic and uterine. Besides the veins 
 that correspond to the arteries, there are several plexuses, 
 belonging both to the vulva and the vagina. Those of the 
 vulva communicate with the vaginal, and these again with 
 the hemorrhoidal. The vaginal are quite large; they are 
 found on both sides of the vagina. The attention of the 
 student should be directed especially to the great vascularity 
 of these parts, and its influence on the pathological condition 
 of them. 
 
 The URETHRA, Fig. 205 (e), should be examined in con- 
 nection with the anterior wall of the vagina. It is from one 
 to one and a half inches in length, and corresponds to the 
 membranous portion of the male urethra. Its direction is 
 downwards and forwards. It is lined by mucous membrane 
 which presents longitudinal folds and mucous crypts. The 
 mucous membrane is surrounded by a layer of spongy erec- 
 tile tissue, and this again by a muscular layer of circular 
 fibres. Some of the longitudinal fibres of the bladder are 
 prolonged into the walls of the urethra. It is susceptible of 
 considerable dilatation, which greatly facilitates the removal 
 of calculi from the bladder. It is in relation, above, with 
 the crura of the clitoris, with the anterior ligaments of the 
 bladder, and a plexus of veins. It perforates the deep peri- 
 neal fascia, and also passes between its layers. The muscles 
 of Wilson and Guthrie have the same arrangement, as they 
 have in the male. 
 
 The perineum should be examined with reference to the 
 support it affords to the parts placed above it, and also with 
 reference to parturition. It is wedge-shaped ; the thick end 
 or base corresponds to the integument, while the thin end is 
 lost in the recto-vaginal septum. 
 
 The bladder. Fig. 205 (4), in the female has the same struc- 
 ture as in the male. It differs somewhat in its shape, being 
 usually larger and more globular. This, however, may be 
 owing to pregnancy, and to the habits of the sex, or the cir- 
 cumstances which surround the female. The uvula vesicse 
 is not quite so large as in the male, which favors the dis- 
 
UTERUS. 483 
 
 charge of calculi from the bladder before they have acquired 
 too great a size. 
 
 UTERUS. 
 
 The uterus, Fig. 204, is placed in the upper and central 
 part of the pelvis, between the bladder and the rectum, being 
 inclined forwards in those who have not borne children, so 
 as to form an angle with the vagina. As seen in the dissect- 
 ing room, it has, perhaps, in a large majority of cases, under- 
 gone some displacement, being most frequently inclined 
 backwards. It does not reach the brim of the pelvis, and is 
 frequently observed to be very much below it. A large 
 portion of it is invested by peritoneum, which covers the 
 fundus, the whole of the posterior and the upper three- 
 fourths of the anterior surface, the remaining fourth being 
 in contact with the bladder. The parts covered by the peri- 
 toneum present a free surface, which is constantly in appo- 
 sition with another surface covered by peritoneum. The 
 lower extremity projects into, and is embraced by, the 
 vagina, which is attached to it higher up posteriorly than 
 anteriorly. Each border below the fundus has attached to 
 it the broad ligament which extends, laterally, to the sacro- 
 iliac symphysis, and, with the uterus and the corresponding 
 ligament on the opposite side, divides the pelvic cavity trans- 
 versely into two culs-de-sac. Between the layers which form 
 this fold of peritoneum, are found the round ligament, the 
 ovarian ligament, and the Fallopian tube. The relative 
 position of each of these parts should be noticed. Where 
 they are attached to the uterus the Fallopian tube is placed 
 above the other two, and partly between them, while the 
 ovarian ligament is situated a little lower than the round 
 ligament. 
 
 The round ligament, or ligamentum teres, Fig. 201 (s), passes 
 outwards, upwards, and forwards, to the inguinal canal, 
 through which it passes to reach the mons veneris and the 
 corresponding labium majus, with which it becomes blended. 
 It is surrounded by a layer of peritoneum, which forms what 
 is called the canal of Nuck. It is composed of a venous 
 plexus, of arteries, of a plexus of nerves, and of muscular 
 fibres. Its use is said to be to support the uterus, and to 
 assist in keeping it in the axis of the pelvic cavity. It is 
 very evident, from its size and structure, that it cannot con- 
 
484 
 
 FEMALE ORGANS OF GENERATION. 
 
 tribute much, if any, to this purpose. It may place in direct 
 sympathetic relation the uterus with the external organs. 
 
 The ovarian ligament Fig. 204 (p), is about two inches in 
 length. It is composed of fibro-muscular tissue, and passes 
 outwards to be inserted into the ovary. It retains the ovary 
 in situ. 
 
 The Fallopian tube, Fig. 204 (s), extends laterally towards 
 the brirn of the pelvis. It is from four to five or six inches 
 
 Fig. 204. 
 
 POSTERIOR VIEW OP THE UTERUS AND ITS APPENDAGES, THE CAVITY OF THE 
 UTERUS BEING SHOWN BY THE REMOVAL OP ITS POSTERIOR WALL, AND THE VAGINA 
 BEING LAID OPEN. a. Fundus, 6, body, and c, cervix of the uterus laid open. The 
 arbor vitse is shown in the cervix; at the constriction just above it is the os uteri 
 internura. d. The os uteri externum. e. The interior of the upper part of the 
 vagina. /. Section of the walls of the uterus, i. Opening into right Fallopian 
 tube, o, o. Ovaries, p, p. Ligaments of ovaries, r. Broad ligament, s, s. Fallo- 
 pian tubes, t, t. Fimbriated extremities. 
 
 long ; placed in the upper border of the broad ligament, it 
 forms a curve with the concavity looking downwards and a 
 little backwards. Its free extremity is usually observed close 
 to the ovary. When this is examined, it will be found to 
 present a nmbriated arrangement ; this is best seen when it 
 is allowed to float in water. It is also expanded or funnel- 
 shaped, which enables it to grasp a part of the ovary, and to 
 receive with greater certainty the ovum which is about to 
 escape from that body. This end of it has been named the 
 corpus fimbriatum, Fig. 204 (tf), and also the morsus diaboli. 
 The Fallopian tube is composed of a serous or peritoneal, a 
 muscular and a mucous layer. The mucous membrane is con- 
 
UTERUS. 485 
 
 tirmous at the uterine orifice with the lining membrane of the 
 uterus, and is blended at its free extremity with the peritoneum. 
 It affords the only instance in the body where a mucous and 
 serous membrane are continuous, or where a serous cavity 
 has an external communication. It is covered with ciliated 
 a'nd columnar epithelia ; it also presents longitudinal rugaa 
 or plica3. The muscular layer is a prolongation of the mus- 
 cular tissue of the uterus. It consists of a longitudinal and 
 circular set of fibres. The uterine orifice will be seen when 
 the cavity of the uterus is exposed. The fimbrise are very 
 frequently met with more or less obliterated by adhesions to 
 each other, or to the surrounding parts. 
 
 The uterus varies in size, and hence its dimensions vary 
 as given by different writers. It is usually from two inches 
 and a half to three inches in length, an inch and a half to two 
 inches in breadth, and about three-fourths <of an inch thick. 
 In women who have borne children it is larger than in those 
 who never have. It is divided into the fundus, body, and 
 cervix. The fundus, Fig. 204 (a), is the part above the attach- 
 ments of the Fallopian tubes ; the cervix, Fig. 204 (c), is the 
 lower part, being separated from the body, Fig. 204 (&), or 
 the portion between the fundus and cervix, by a slight con- 
 striction. . Its weight varies from one to two ounces, accord- 
 ing as it v.aries in size. 
 
 In form* it resembles a pear flattened on two sides, being 
 a little more convex posteriorly than anteriorly. The cervix 
 is constricted at both ends, being shaped like a wine-cask. 
 The part that projects into the vagina is divided by a trans- 
 verse fissure into an anterior and a posterior lip. The latter 
 is not quite so thick as the former, but appears, when exa- 
 mined in situ, to be a little more prominent, or to project a 
 little more than the former, which is owing to the vagina 
 being inserted higher on the cervix behind than in front. 
 The vaginal orifice has been called the os uteri, os uteri exter- 
 num, or os tineas, Fig. 204 -(d\ from a fancied resemblance it 
 has to the mouth of the tench fish. 
 
 It is exceedingly important that the student should obtain 
 a correct idea of the cervix of the uterus when in a perfectly 
 healthy state, in order that he may be able to detect any 
 deviation from a strictly physiological condition. The time 
 has been when a student could graduate in a respectable 
 institution without feeling that he might be required at a 
 
486 FEMALE OKGANS OF GENERATION". 
 
 very early period, or perhaps at any period in his practice, 
 to inspect the cervix of the womb, and determine its condi- 
 tion in regard to health or disease. No one, however, can 
 do this at the present time without proving false to himself 
 and to those who shall confide in his professional skill. 
 Drawings prepared by the most skilful artists may be within 
 his reach, but they alone should not satisfy his desire 
 for accurate knowledge. They may be invaluable as aids, 
 but should never be relied on exclusively as substitutes for 
 nature. Is there not just reason to apprehend that the vis- 
 Fig. 205. 
 
 A VERTICAL SECTION or THE FEMALE PELVIS AND VISCERA. 1. The symphysis 
 pubis, to the upper part of which the tendon of the rectus muscle is attached. 2. Tho 
 abdominal parietes. 3. The collection of fat, forming the projection of the mons 
 veneris. 4. The urinary bladder. 5. The entrance of the left ureter. 6. The 
 canal of the urethra, converted into a mere fissure by the contraction of its walls. 
 7. The meatus urinarius. 8. The clitoris, with its praeputium, divided through the 
 middle. 9. The left nympha. 10. The left labium majus. 11. The rneatus of the 
 vagina, narrowed by the contraction of its sphincter. 12. The canal of the vagina, 
 upon which the transverse rugae are apparent. 13. The thick wall of separation 
 between the base of the bladder and the vagina. 14. The wall of separation be- 
 tween the vagina and rectum. 15. The perineum. 16. The os uteri. 17. Cervix 
 uteri. 18. The fundus uteri. The cavity of the uterus is seen in the centre of 
 the organ. 19. The rectum, showing the disposition of its mucous membrane. 20. 
 The anus. 21. The upper part of the rectum, invested by the peritoneum. 22. The 
 recto-uterine fold of the peritoneum. 23. The utero-vesical fold. 24. The reflection 
 of the peritoneum, from the apex of the bladder, upon the urachus, to the internal 
 surface of the abdominal pariotes. 25. The last lumbar vertebra. 26. The eacrum. 
 27. The coccyx. 
 
UTERUS. 487 
 
 cera contained in the pelvis receive altogether too small a 
 share of the attention of the student in the dissecting-room, 
 the only place where a proper knowledge of them can be 
 acquired ? 
 
 The cavity of the uterus may be exposed by simply mak- 
 ing a vertical incision through its parietes, and forcibly 
 separating the cut edges, or it may be done by making a 
 transverse vertical incision, so as to divide it into two equal 
 parts, one being the anterior and the other the posterior half. 
 The walls of the uterine cavity vary in thickness at different 
 points. Where the Fallopian tubes join them, they are not 
 more than two or three lines thick ; the anterior and posterior 
 walls are from four to six lines thick ; the walls of the cervix 
 are not so thick as those of the body. Like the vaginal, the 
 anterior and posterior surfaces of the uterine cavity are con- 
 stantly in apposition. Owing to the great thickness of the 
 walls, the cavity is comparatively very small. It has the shape 
 of a curvilinear triangle, the superior angles corresponding to 
 the mouths of the Fallopian tubes, and the lower angle to the 
 os uteri internum, or isthmus uteri, Fig. 204 (c), the opening be- 
 tween the body and the cervix, or, if the latter be included, 
 the os externum. The mucous membrane is very thin and 
 delicate, so much so that its existence l?as been denied or 
 doubted by some. It is more vascular in the body than in 
 the cervix, especially during the menstrual period. In the 
 cervix, a vertical ridge or column is observed in the median 
 line both on the anterior and posterior wall, from which pro- 
 ceed other ridges at an obtuse angle. The term arbor vitce 
 uterina, Fig. 204 (c), has been employed to designate this 
 appearance. It commonly becomes less apparent after the 
 first parturition, although not necessarily so. Numerous fol- 
 licles may be noticed in the cervix, especially near its external 
 os, and some in the body. They have been named the ovula 
 of Ndboth from the circumstance that Naboth happened to 
 observe them in a diseased condition, and thinking they were 
 ovula, described them as such. 
 
 The openings that lead into the Fallopian tubes, Fig. 204 
 (i), are so small that they are scarcely perceptible to the 
 naked eye. The cavity is elongated towards them so as to 
 form cornua. 
 
 The muscular coat of the uterus is hard, dense, and of a 
 grayish color. It consists of fibres, which, in the unimpreg- 
 nated uterus, cannot be traced on account of their compact- 
 
488 FEMALE ORGAN'S OF GENERATION. 
 
 ness and interlacing apparently in every direction. They 
 are non-striated, and hence belong to those of organic life. 
 They are arranged in the body in a superficial and a deep- 
 seated layer. Anteriorly and posteriorly the superficial have 
 a longitudinal direction; laterally they are oblique, and are 
 prolonged into the round and ovarian ligaments, and into the 
 walls of the Fallopian tubes. The deep-seated are arranged in 
 the form of two hollow cones, the bases of which correspond 
 to the median line, interlacing with the fibres of the opposite 
 side, while the apices surround the cornua, and extend into 
 the Fallopian tubes and the round and ovarian ligaments. 
 The cervical portion of the muscular coat consists of circular 
 fibres which interlace and cross each other. 
 
 THE OVARIES. 
 
 The ovaries, Fig. 204 (o), are the analogues in the female, 
 of the testes in the male. There are two of them, one on 
 each side. Each is placed between the layers of the broad 
 ligament, behind the Fallopian tube, and about two inches 
 from the uterus, to which it is connected by the round and 
 broad ligaments. It is a small oval body flattened on the 
 sides from before backwards. They increase in size during 
 pregnancy, and like the testicles, become atrophied in old 
 age. Their anterior, posterior, and upper surfaces are free. 
 One or more of the firnbriaB are usually attached to their 
 outer extremities. Immediately under the peritoneum is a 
 thick, dense, fibrous coat, corresponding to the tunica albu- 
 ginea of the testicle. The peritoneum adheres to this in the 
 same manner as the tunica vaginalis testis adheres to the 
 testicle. From the inner surface fibrous bands are sent in- 
 wards into a cellulo-vascular substance named the stroma. 
 Besides the fibrous and serous coats there is a vascular one, 
 similar to the tunica vasculosa of the testicle. Throughout 
 the stroma are distributed the Graafian vesicles; they vary 
 very much in size and number. They can be best observed 
 just after parturition, when the ovaries are soft and swollen. 
 Each vesicle consists of two coats, an external and internal, 
 and contains a yellowish fluid and an ovum. When a vesicle 
 ruptures, and the ovum escapes, the remains of the vesicle, it 
 it is supposed, forms a brownish-yellow body called corpus 
 luteum. 
 
THE LOWER EXTREMITY. 489 
 
 The vessels and nerves of the uterus and ovaries are no- 
 ticed in the dissection of the vessels and nerves of the pelvic 
 cavity. 
 
 CHAPTER II. 
 
 OF THE LOWER EXTREMITY. 
 
 SECT. I. DISSECTION OF THE ANTERIOR PART OF THE THIGH. 
 
 THE position and connections of the parts concerned in 
 femoral or crural hernia are such that the examination of 
 them naturally precedes the general dissection of the anterior 
 part of the thigh; hence it will be unnecessary to describe 
 again the parts which have been examined specially as well 
 as in their relations to femoral hernia. 
 
 9 
 
 ANATOMY OF FEMORAL HERNIA. 
 
 In femoral or crural hernia the bowel protrudes under 
 Poupart's ligament, near its insertion into the spine and crest 
 of the pubic bone. The parts which are involved in this 
 form of hernia are situated below, behind, and above Pou- 
 parfc's ligament. Those below it are the skin, the superficial 
 fascia including the vessels, nerves, and lymphatics which are 
 found in it, the fascia lata and the infundibuliform sheath of 
 the femoral artery and vein ; behind it are found the psoas 
 inagnus and iliacus internus muscles, the anterior crural 
 nerve, the external iliac artery and vein, the infundibuliform 
 sheath, and the femoral ring; above it and in the abdomen 
 are the peritoneum, the sub-peritoneal areolar tissue, and the 
 fasciae trans versalis and iliaca. 
 
 The parts in the thigh below Poupart's ligament can be 
 exposed without opening the cavity of the abdomen ; but 
 the dissection of the parts placed behind and above it, require 
 this cavity to be opened. The integument must be dissected 
 off' from the anterior portion of the upper third of the thigh. 
 This may be done by making an incision through the skin, 
 from the anterior superior spinous process of the ilium, 
 directly downwards to the middle third of the thigh, and 
 then extending it transversely across to the inner side of 
 
490 
 
 THE LOWER EXTREMITY. 
 
 Fig. 206. the thigh. It is supposed that the 
 
 parts in the inguinal region have al- 
 ready been dissected, so that no new 
 incisions will be required above Pou- 
 part's ligament. 
 
 Having exposed the superficial fas- 
 cia, the student should now look for 
 the subcutaneous vessels, nerves, and 
 lymphatic glands in this region. 
 
 The arteries are the arteria ad cutem 
 abdominis, the external circumflex 
 ilii, the superficial external pudic, and 
 the inguinal branches. They all arise 
 a short distance below Pou part's liga- 
 ment ; sometimes two or three of them 
 arise by a common trunk. 
 
 The arteria ad cutem abdominis, or 
 superficial epigastric, Fig. 206 (2), 
 passes upwards an& inwards over Pou- 
 part's ligament, in the direction of the 
 umbilicus. It is distributed to the 
 integument. 
 
 The superior external pudic, Fig. 206 
 (ie), goes inwards to supply the in- 
 tegument on the pubes, the penis, and 
 the scrotum. 
 
 The external circumflex ilii, Fig. 206 
 (i s), passes outwards towards the an- 
 terior superior spinous process of the 
 
 A VIEW OF THE ANTERIOR AND INNER ASPECT OP THE THIGH, SHOWING THE 
 COURSE AND BRANCHES OF THE FEMORAL ARTERY. 1. The lower part of the 
 aponeurosis of the external oblique muscle ; its inferior margin is Poupart's liga- 
 ment. 2. The external abdominal ring. 3, 3. The upper and lower parts of the 
 sartorius muscle; its middle portion having been removed. 4. The rectus. 5. The 
 vastus interims. 6. The patella. 7. The iliacus and psoas ; the latter being 
 nearest the artery. 8. The pectineus. 9. The adductor longus. 10. The tendi- 
 nous canal for the femoral artery formed by the adductor magnus and vastus in- 
 ternus muscles. 11. The adductor magnus. 12. The gracilis. 13. The tendon 
 of the semi-tendinosus. 14. The femoral artery. 15. The external circumflex 
 ilii artery taking its course along the line of Poupart's ligament, to the crest of the 
 ilium. 2. The superficial epigastric artery. 16. The two externnl pudic arteries, 
 superior and inferior. 17. The profunda artery giving off 18, its external circumflex 
 branch; and lower down the three pert'orantes. A small portion of the internal cir- 
 cumflex artery (8) is seen behind the inner margin of the femoral, just below the 
 deep external pudic artery. 19. The anastomotica, magna, descending to the knee, 
 upon which it ramifies (6). 
 
ANATOMY OF FEMOEAL HEENIA. 
 
 ilium, where it is lost in the integument. Fig. 208. 
 
 The inguinal branches supply the lymph- 
 Fig. 207. 
 
 491 
 
 PLAN OF THE CUTANEOUS NERVES ON THE FRONT OP 
 THE THIGH. 1, 2. Branches of the superior and mid- 
 dle musculo-cutaneous nerves. 3, 3. Branches of exter- 
 nal cutaneous nerve. 4. Branches of middle cutaneous 
 nerve. 5, 5. Internal cutaneous ; the lower number re- 
 fers to the anterior division of this nerve. 6. Long or 
 internal saphenous nerve, when become subcutaneous. 
 7. Crural branch of the genito-crural nerve. 
 
 atic glands and areolar tissue in this 
 region. 
 
 The principal vein is the internal sa- 
 phenous, Fig. 208. This is situated on 
 
 SAPHENOUS OPENING IN THE FASCIA LATA, INTERNAL SAPHENOUS VEIN, &c 
 I. Sapbenous opening, a. External epigastric vein. b. External pudic vein. c. 
 Superficial circumflex ilii. d. Beginning of external saphenous vein. 
 
492 THE LOWER EXTREMITY. 
 
 the inner and anterior part of the thigh, and lies close to 
 the fascia lata. It receives several branches, Fig. 207 (a, b, c), 
 some of which accompany the arteries already described. 
 
 The nerves (Fig. 207) are derived from the lumbar plexus, 
 the genito-crural, and the anterior crural. They penetrate 
 the fascia lata obliquely at different points, and after run- 
 ning some distance they leave it to become subcutaneous. 
 The integument on the upper and anterior part of the thigh 
 is supplied principally by three branches. One of them, a 
 branch of the superior musculo-cutaneous, reaches the thigh 
 through the external abdominal ring; another one, a branch 
 of the genito-crural, passes through the fascia lata just be- 
 low the -middle of Poupart's ligament; the third one, a 
 branch of the inferior musculo-cutaneous or the external cuta- 
 neous nerve, pierces the fascia below the anterior superior 
 spinous process of the ilium. The middle cutaneous nerve 
 sometimes becomes subcutaneous near the junction of the up- 
 per with the middle third of the thigh, but usually lower 
 down. Very little importance is attached to these nerves in 
 connection with the anatomy of femoral hernia. 
 
 The lymphatic glands, Fig. 148 (7), are divided into the 
 deep and superficial; the former are placed beneath the fascia 
 lata, and the latter are imbedded in the superficial fascia. 
 The superficial are again divided into the superior and infe- 
 rior ; the superior lie along Poupart's ligament, some above 
 and others below it ; the inferior are situated near the saphe- 
 nous vein. These glands are frequently found enlarged, so 
 that the student can often get in his dissection a distinct 
 view of their location. They vary in number in different 
 subjects ; sometimes several are joined together. The super- 
 ficial lymphatics of the penis pass through the glands situated 
 near Poupart's ligament, and hence the liability of these to 
 become affected in venereal disease. 
 
 The superficial fascia should now be removed. It may be 
 raised and reflected in the same manner as the skin was; or 
 it may be turned off* from above downwards and from within 
 outwards. The saphenous vein must be dissected out as far 
 up as where it enters the saphenous opening, cutting it 
 across below but not above, as its connection with the infun- 
 dibuliform sheath of the femoral vessels should be, for the 
 present, preserved. In raising the superficial fascia in front 
 of and around the saphenous opening, it will be found to 
 
ANATOMY OF FEMORAL HERNIA. 493 
 
 contain more or less fibrous tissue which connects it firmly 
 to the fascia lata, especially to the surface of the falciform 
 process and its crescentic border. Sometimes this connection 
 between the two fasciae is so intimate that in separating them 
 it seems more like making an artificial division than follow- 
 ing any natural line of separation. On account of its fibrous 
 character, its close connection to the fascia lata, and the nu- 
 merous small openings in it for the transmission of lympha- 
 tics, this part of the superficial fascia has been described as a 
 distinct fascia, under the name of cribriform fascia. There is 
 no good reason, however, why it should be so regarded or 
 described. 
 
 To raise the superficial fascia in any part of the femoral 
 region without getting through the fascia lata requires a 
 good deal of care, and more particularly if the subject happens 
 to be fat. No student should attempt to remove it with the 
 expectation of preserving the subjacent parts entire unless 
 he has previously obtained a clear idea of them from books 
 or previous demonstrations. The parts which require the 
 most care not to injure in the dissection are, the falciform 
 process in front of the femoral vessels, its crescentic border, 
 Hey's ligament, and the infundibuliform sheath where it cor- 
 responds to the saphenous opening, and is perforated by the 
 saphenous vein. In his first dissection of this region, the 
 student had better remove the superficial fascia corresponding 
 to these parts piecemeal. 
 
 The/ascia lata, Fig. 150 (i 7), Fig. 208, is the proper invest- 
 ing membrane of the thigh. It is aponeurotic in structure, 
 resembling in some parts a broad tendon. It forms a common 
 sheath to the muscles of the thigh, and furnishes septa which 
 pass between them and separate them from each other. It 
 will be referred to from time to time as the dissection of the 
 thigh is continued. In the region which is now being exa- 
 mined, it constitutes a most important feature in the anatomy 
 of femoral hernia. An opening occurs in it just below the 
 inner portion of Poupart's ligament, through which the in- 
 ternal saphenous vein passes to open into the femoral vein, 
 and through which the bowel escapes in femoral hernia. 
 This orifice is named the saphenous opening, Fig. 148 (20). 
 The manner in which it is formed is a little complex; or, it 
 is apt to appear so to the student. 
 
 In describing this portion of the fascia lata, it must be pre- 
 42 
 
494 THE LOWER EXTREMITY. 
 
 sumed that the dissector has some knowledge of the muscles 
 and vessels situated beneath it, also of Poupart's ligament 
 including Gimbernat's, and of the infundibuliform sheath 
 of the vessels. 
 
 It is divided into two parts, by the saphenous opening. 
 The portion which is situated on the inner side of the 
 opening is named the pubic or pectineal, and, that placed 
 on the outer side and above, the sartorial or iliac portion. 
 Below the opening the fascia is continuous from one side of 
 the thigh to the other. 
 
 The pubic portion is usually quite thin, and lies directly 
 on the adductor longus and pectineus muscles. It is attached, 
 above, to the body, the spine, and the pectin eal line of the 
 pubic bone ; externally, it dips down behind the infundibu- 
 liform sheath, and of course behind the femoral vein and 
 artery which the sheath incloses. 
 
 The iliac portion lies on the sartorius, iliacus internus and 
 psoas magnus muscles, and the infundibuliform sheath with 
 its inclosed vessels, and in front of the femoral ring. It is 
 attached, above, to the anterior superior spinous process of 
 the ilium, and to the lower border of the whole of Poupart's 
 ligament, including Gimbernat's. Internally, it forms the 
 outer and upper boundary of the saphenous opening. This 
 border is curved with the concavity looking to the pubic 
 side and somewhat downwards ; the term crescentic has been 
 applied to it. 
 
 That portion of the fascia which lies in front of the vessels 
 and the femoral ring is named the fa kiform process, while that 
 portion of the process which is placed in front of the ring 
 is called Hetfs ligament. Hey's ligament, then, is under- 
 stood to be, simply the small portion of the fascia lata 
 which lies in front of the femoral ring and is attached to 
 the border of Gimbernat's ligament, and, by a narrow point, 
 to the pectineal line. 
 
 It will now be seen that the infundibuliform sheath and 
 the femoral vessels lie behind the iliac and in front of the 
 pubic portion of the fascia lata; and that the saphenous 
 opening is formed by the division of the fascia lata into these 
 two portions. 
 
 The saphenous opening, Fig. 148 (20), is of an oval form 
 with the narrow extremity directed upwards. The lower 
 boundary is named the semilunar margin, and is formed by a 
 
ANATOMY OF FEMOKAL HERNIA. 495 
 
 doubling of the fascia on itself; it is easily found by trac- 
 ing the saphenous vein upwards. The outer and upper 
 boundary is formed by the crescentic border of the falciform 
 process. This does not always present a well-defined mar- 
 gin. It may usually be found by drawing the semilunar 
 margin downwards with the forceps or tenaculum, and thus 
 making it tense. The inner boundary is formed by the ex- 
 ternal surface of the pectineal portion of the fascia. 
 
 In dissecting the saphenous opening, the student must 
 bear in mind that the femoral vessels are not to be exposed, 
 as it would destroy the infimdibuliform sheath which has not 
 yet been examined. The saphenous vein perforates the 
 sheath, and hence it should not be traced at this stage of the 
 dissection further than to the saphenous opening. 
 
 The parts in the abdomen should now be examined. As 
 they have already been described in detail in connection 
 with the other parts of the abdomen, it will only be neces- 
 sary to notice them now in their relations to hernia. They 
 consist of the peritoneum, the subperitoneal areolar tissue, 
 and the fasciae transversalis and iliaca. 
 
 The peritoneum is the most internal layer, lying next to 
 the bowels. It presents a depression or fossa bounded, on 
 the outer side, by a fold caused by the remains of the umbili- 
 cal artery of the foetus projecting inwards, and below by the 
 horizontal ramus of the pubic bone. This fossa corresponds 
 to the femoral ring. 
 
 The subperiioneal areolar tissue is placed between the peri- 
 toneum and the fasciae transversalis and iliaca. It connects 
 the peritoneum and these fasciae, and contains the epigastric, 
 the spermatic, and the external iliac vessels, also the vas defer- 
 ens, the genito-crural nerve, and lymphatics. It is not equally 
 diffused between these membranes, but is more abundant in 
 some places than in others. It, together with a lymphatic 
 gland, fills the crural canal; this part of it forms what has 
 improperly been called the septum crurale. This tissue is 
 always carried down by the bowel in hernia, and is then 
 converted into a well-marked membranous layer which has 
 been designated the fascia propria. This should now be care- 
 fully dissected off from the fasciae and the other parts be- 
 neath it. It will then be seen that the transversalis and iliac 
 fasciae are united along Poupart's ligament from the anterior 
 superior spinous process of the ilium to near the external 
 
496 THE LOWER EXTREMITY. 
 
 iliac artery, thus, closing the space between the ligament and 
 the iliacus interims and psoas magnus muscles; but between 
 the point where the junction of the two fasciae ceases on Pou- 
 part's ligament and the spine of the pubic bone, or rather 
 Gimbernat's ligament, a large opening is observed between 
 Poupart's ligament in front and the os pubis behind. In- 
 stead of the fasciae, however, terminating at the margin of 
 
 Fig. 209. 
 
 A SECTION OF THE STRUCTURES WHICH PASS BENEATH THE FEMORAL ARCH. 1. 
 Poupart's ligament. 2, 2. The iliac portion of the fascia lata, attached along the 
 margin of the crest of the ilium, and along Poupart's ligament, as far as the spine 
 of the os pubis (3). 4. The pubic portion of the fascia lata, continuous at (3) with 
 the iliac portion, and passing outwards behind the sheath of the femoral vessels to 
 its outer border at 5, where it divides into two layers; one is continuous with the 
 sheath of the psoas (6) and iliacus (7); the other (8) is lost upon the capsule of the 
 hip-joint (9). 10. The anterior crural nerve, inclosed in the sheath of the psoas and 
 iliacus. 11. Gimbernat's ligament. 12. The femoral ring, within the femoral 
 sheath. 13. The femoral vein. 14. The femoral artery: the two vessels and the 
 ring are surrounded by the femoral sheath, and thin septa are sent between the 
 anterior and posterior wall of the sheath, dividing the artery from the vein, and 
 the vein from the femoral ring. 
 
 this opening, they are prolonged downwards to the extent of 
 about an inch and a half, forming a sort of a pouch open at 
 the lower end for the passage of the femoral vessels. This 
 pouch is divided lengthwise into three compartments or canals, 
 Fig. 209 (14), by two fibrous septa which pass from its anterior 
 to its posterior wall. The external iliac artery passes through 
 
ANATOMY OF FEMORAL HERNIA. 497 
 
 the outer, and the external iliac vein the middle one, while 
 the inner one, which is shorter than the other two, is occupied 
 by subperitoneal areolar tissue and a lymphatic gland, and is 
 named the crural canal. The pouch itself is the infundibuli- 
 form sheath of the femoral vessels, noticed in the dissection of 
 the parts below Poupart's ligament. 
 
 The crural canal should now be examined. To do this, 
 the areolar tissue and lymphatic gland, if one be present, 
 must, in the first place, be removed; the finger should then 
 be introduced into, and gently pushed down to the saphe- 
 nous opening, having first flexed the thigh on the abdomen 
 and rotated it inwards. If the thigh be now extended 
 and rotated outwards, the upper part of the canal will be 
 constricted by Poupart's and Hey's ligaments being made 
 tense, and the effect of the position of the limb upon the 
 neck of a hernia! tumor distinctly understood, as well as the 
 importance of placing the limb in a proper position when 
 attempting to return the bowel either by taxis or after an 
 operation in case of strangulation. 
 
 The upper orifice of the crural canal is called the crural or 
 femoral ring, Fig. 209 (12). Its boundaries are, in front and 
 on the inner side, Hey's ligament and Poupart's including 
 Girnbernat's ligament; on the outer side, the femoral vein ; and 
 behind, the pubic bone covered by a lamina of fibrous tis- 
 sue. These boundaries are exterior to the proper walls of 
 the canal. Dropping the terms of Hey's ligament and GHm- 
 bernat's ligament, it might simply be said that the fascia lata 
 and Poupart's ligament are placed in front and on the inner 
 side of the upper part of the crural canal, and must be re- 
 garded, when considered in their relations to the neck of a 
 hernial tumor, as forming one structure. The crural canal 
 cannot be said to have any external orifice, unless the saphe- 
 nous vein forms one in entering the sheath of the vessels. 
 
 There is no artery of much size in the majority of cases 
 that has any direct relation to the femoral ring. There is 
 usually a small anastomosing branch which crosses over the 
 ring to the obturator artery. This branch is occasionally 
 met with of considerable size. The obturator artery not un- 
 frequently arises from either the epigastric or external iliac, 
 and passes inwards to reach the upper part of the obturator 
 foramen. In this case it may be placed either above or be- 
 low the neck of a hernial tumor; but, if it arises from the 
 
 42* 
 
498 
 
 THE LOWER EXTREMITY. 
 
 iliac artery, some distance above Pou part's ligament, it will 
 have no direct relation to hernia. 
 
 The transversalis and iliac fasciae may now be dissected up 
 
 Fig. 210. 
 
 AFTER THE REMOVAL OF THE LOWER PART OF THE EXTERNAL OBLIQUE (WITH 
 THE EXCEPTION OF A SMALL SLIP INCLUDING PoUPART'S LlGAMENT), THE LOWER 
 PORTION OF THE INTERNAL OBLIQUE WAS RAISED, AND THEREBY THE TRANSVER- 
 SALIS MUSCLE AND FASCIA HAVE BEEN BROUGHT INTO VIEW. THE FEMORAL 
 ARTERY AND VEIN ARE SEEN TO A SMALL EXTENT, THE FASCIA LATA HAVING BEEN 
 
 TURNED ASIDE AND THE SHEATH OF THE BLOODVESSELS LAID OPEN. 1. External 
 
 oblique muscle. 2. Internal oblique. 2'. Part of same turned up. 3. Transver- 
 salis muscle. Upon the last-named muscle is seen a branch of the internal cir- 
 cumflex ilii artery, with its companion veins ; and some ascending tendinous fibres 
 are seen over the conjoined tendon of the two last-named muscles. 4. Transversalis 
 fascia. 5. Spermatic cord covered with the iufnndibulifonii fascia from preceding. 
 6. Upper angle of the iliac part of fascia lata. 7. The sheath of the femoral ves- 
 sels. 8. Femoral artery. 9. Femoral vein. 10. Saphenous vein. 11. A vein 
 joining it. 
 
 for a short distance above the mouth of the infundibuliform 
 sheath in order to trace them down as they enter into the 
 formation of this sheath. In doing this, the fascia transver- 
 salis will be found to be intimately connected to some apo- 
 
ANATOMY OF FEMORAL HERNIA. 499 
 
 neurotic or tendinous fibres which arise to the outer side of 
 the artery, and, arching over the mouth of the sheath, are in- 
 serted into the linea pectinea; these fibres form what has 
 been called the deep femoral arch. "When observed from 
 above they appear, in front of the sheath, to be a part of 
 Poupart's ligament. When the fascia has been separated 
 from these fibres, the handle of the scalpel can generally be 
 carried down beneath them to the saphenous opening, and 
 also to the outer side of it, so as to separate the falciform 
 
 Erocess of the fascia lata from the sheath. The parts in 
 -ont of the sheath may next be divided and reflected off for 
 the purpose of examining the sheath with its septa, and the 
 artery and vein as they lie in it. The anterior crural nerve, 
 Fig. 209 (i o), will be found four or five lines external to the 
 artery, occupying a groove formed by the psoas and iliacus 
 muscles. 
 
 If the student will now review the parts which he has just 
 dissected with reference to the protrusion of the bowel in 
 hernia, he will have no difficulty in understanding the man- 
 ner in which the protrusion takes place, and the new rela- 
 tions the bowel acquires to the surrounding parts. 
 
 He will observe that the bowel, in escaping from the cavity 
 of the abdomen, first passes through the femoral ring and gets 
 into the crural canal, carrying with it the peritoneum and 
 the subperitoneal areolar tissue. If it remained in the canal, 
 it would be called concealed femoral hernia. It does not, how- 
 ever, generally stop here, but forces its way through that part 
 of the anterior wall of the canal which corresponds to the 
 saphenous opening in the fascia lata, and then turns upwards 
 and outwards over the falciform process, and sometimes over 
 Poupart's ligament, beneath the superficial fascia and the skin, 
 thus forming a curve, with the concavity looking upwards, 
 and the convexity downwards. 
 
 It will be seen that the bowel is now covered, proceeding 
 from without inwards; first, by the skin; secondly, by the 
 superficial fascia ; thirdly, by the subperitoneal areolar tissue 
 or ih.G fascia propria ; and fourthly, by ih& peritoneum which 
 forms the sac. The first two layers are obtained outside the 
 femoral canal, and the other two, one within it, and one in 
 the cavity of the abdomen. 
 
 In reducing the bowel by taxis, it should be pushed down- 
 wards, backwards, and upwards, the lower extremity having 
 
500 THE LOWER EXTREMITY. 
 
 first been placed in a proper position. In cutting a stricture 
 at the upper part of the crural canal, the incision should be 
 made upwards, or upwards and inwards. 
 
 In continuing the dissection of the thigh, the integument 
 must be dissected off down as far as the tubercle of the tibia, 
 both in front and on the sides. To do this, the incision, com- 
 menced at the anterior superior spinous process of the ilium, 
 may be extended down below the outer side of the knee, and 
 then carried across the leg to the inner side. Having done 
 this, the integument may be reflected from the outer to the 
 inner side of the limb. 
 
 The superficial fascia of the thigh requires no further no- 
 tice. It passes over the knee, and is continuous with that of 
 the leg. The saphenous vein may be traced down as far as 
 the skin has been removed. The cutaneous nerves, Fig. 208, 
 as was mentioned in the previous dissection, are derived from 
 the lumbar plexus, the genito-crural and the anterior crural, 
 and also from the obturator nerve. 
 
 The anterior branch of the external cutaneous nerve usually 
 perforates the fascia lata about four inches below Poupart's 
 ligament. It supplies the integument on the inner and ante- 
 rior part of the thigh. 
 
 The middle cutaneous nerve, a branch of the anterior crural, 
 usually becomes subcutaneous four or five inches below 
 Poupart's ligament. It passes down on the fore part of the 
 thigh to the knee. It frequently divides into two branches, 
 nearly of the same size, soon after perforating the fascia lata. 
 
 The internal cutaneous nerve is also a branch of the anterior 
 crural nerve. It perforates the fascia lata on the inner part 
 of the thigh, about three inches above the knee, and then 
 passes down to the internal condyle of the femur, where it 
 turns outwards over the patella, and ends in the skin on the 
 outer side of the knee. In its course down the thigh, this 
 nerve frequently gives off several branches, which perforate 
 the fascia lata at different points, and become subcutaneous. 
 One or two of these branches accompany the saphenous vein 
 for a short distance. 
 
 The internal saphenous nerve, Fig. 207 (R), becomes subcu- 
 taneous at the inner side of the knee, and then continues as 
 such down the leg, in company with the internal saphenous 
 vein. Before becoming subcutaneous, it gives off a branch, 
 which is lost in the skin which covers the patella. Quite a 
 
ANTERIOR PAKT OF THE THIGH. 501 
 
 large cutaneous branch is sometimes found on the inner side of 
 the knee and the upper and back part of the leg, that is de- 
 rived from the obturator nerve. When this occurs, it takes 
 the place of a branch of the internal cutaneous nerve. The 
 cutaneous nerves of the thigh anastomose with each other. 
 
 The superficial fascia may now be removed by first making 
 an incision through it down the middle of the thigh, and over 
 the patella, and then reflecting it outwards and inwards. A 
 bursa mucosa, situated in the subcutaneous areolar tissue, 
 between the skin and the patella, should be observed. The 
 density of the fascia, and the absence of adipose tissue in the 
 vicinity of the patella, should also be noticed. However 
 much adipose substance there may be above and below the 
 patella, there is very little, if any, ever found in front of it. 
 
 In examining the fascia lata at this stage of tfre dissection, 
 it will be found to divide into two layers below the anterior 
 superior spinous process of the ilium, to inclose the tensor 
 vagince femoris muscle, and then to pass to the gluteus medius. 
 It should not be exposed much posterior to the tensor muscle 
 at present. The superficial layer may now be divided from 
 the spinous process downwards, and somewhat backwards, 
 to the extent of three or four inches, exposing the tensor 
 vaginae femoris. 
 
 The TENSOK VAGINJS FEMORIS, Fig. 211 (4), arises tendi- 
 nous from the anterior superior spinous process of the ilium, 
 and, passing downwards and backwards, is inserted, about four 
 inches below its origin, into the fascia lata ; the two layers 
 which form its sheath being here united. In dissecting out 
 the tensor vaginas femoris, some care is necessary not to ex- 
 pose the gluteus medius and minimus muscles. Below and 
 behind the insertion of the tensor vaginae femoris, the fascia 
 lata is connected to the tendon of the gluteus maximus, and, 
 below this, to the linea aspera and the external condyle of 
 the femur. The action of the tensor vaginae femoris will 
 now be easily understood. It first renders the fascia tense, 
 and then rotates the thigh inwards by acting on the linea 
 aspera through the fascia. 
 
 The vastus externus Fig. 211 (7), arises for some distance 
 from the fascia lata, near its attachment to the linea aspera, 
 and it will be seen, in the dissection of the posterior part of 
 the thigh, that the short head of the -biceps flexor arises 
 
502 
 
 THE LOWEK EXTREMITY. 
 
 from the corresponding surface on the other side. This 
 part of the fascia is called the external intermuscular septum. 
 It separates the muscles on the outer from those on the back 
 part of the thigh. Below, the fascia passes down in front of 
 the knee. Internally, it is inserted into the linea aspera from 
 the trochanter minor to the internal condyle. This part 
 forms the internal intermuscular septum. 
 
 As the dissection is continued, it will be found that the 
 fascia lata sends in processes from its 
 Fig. 211. inner surface to form sheaths for the 
 
 different muscles, and also for the femo- 
 ral vessels. If, in removing this fascia, 
 the student will first look at the drawing, 
 Fig. 211, he will see the muscles which 
 are to be exposed, and then, by dividing 
 the fascia on each muscle, and in the 
 direction of its fibres, he will have no 
 difficulty in making a clear exposition of 
 them. With a little care and patience, 
 he will be able to do this, and, at the 
 same time, preserve the principal vessels 
 and nerves. 
 
 The SARTORIUS, Fig. 211 (s), arises ten- 
 dinous from the anterior superior spinous 
 process of the ilium and from the notch be- 
 low, passes obliquely downwards, inwards, 
 and somewhat backwards, to the lower 
 third of the thigh, and then directly down- 
 wards to the inner side of the knee-joint, 
 where it becomes tendinous, and, curving 
 outwards round the joint, is inserted into 
 the tibia just below and on the inner side 
 of its tubercle. It covers the tendons of the 
 gracilis and semi-tendinosus, and is con- 
 nected to the deep fascia of the leg. The 
 internal saphenous nerve will be seen 
 
 THE MUSCLES OF THE ANTERIOR FEMORAL REGION. 1. The crest of the ilium. 
 2. Its anterior superior spinous process. 3. The gluteus medius. 4. The tensor 
 vaginaa femoris ; its insertion into the fascia lata is shown inferiorly. 5. The 
 surtorius. 6. The rectus. 7. The vastus externus. 8. The vastus internus. 9. 
 The patella. 10. The iliacus internus. 11. The psoas magnus. 12. The pectineus. 
 13. The adductor longus. 14. Part of the adductor magnus. 15. The gracilis. 
 
ANTERIOR PART OF THE THIGH. 
 
 503 
 
 emerging between its anterior border and the tendon of the 
 gracilis, opposite the internal condyle. It increases somewhat 
 in breadth as it descends to the lower part of the thigh. Its 
 fibres are the longest in the body. Its action is first to flex 
 the leg on the thigh, and then the thigh on the pelvis, and, 
 at the same time, draw the limb across the other. 
 
 The gracilis may be dissected next, 
 as its dissection will involve no im- Fi S- 21 2. 
 
 portant vessel or nerve. 
 
 The GRACILIS, Fig. 211 (i 5), arises 
 by a thin, flat tendon, from the body 
 and ramus of the pubic bone by the 
 side of the symphysis, descends on the 
 inner side of the thigh and knee-joint, 
 and is inserted into the inner side of 
 the tubercle of the tibia. It diminishes 
 in width from above downwards ; its 
 borders look forwards and backwards; 
 and it becomes tendinous a short dis- 
 tance above the knee. Its action is to 
 flex the leg on the thigh and move 
 it towards the opposite limb. 
 
 The sartorius and gracilis may 
 now be detached at their origins and 
 turned downwards; and also the 
 tensor vaginae femoris. They must 
 be preserved for the purpose of re- 
 placing them at a future time to 
 study their relations to other parts. 
 On raising the sartorius, the middle 
 cutaneous nerve will be seen perfo- 
 rating it. 
 
 The next stage of the dissection 
 will include the femoral artery and 
 its branches, the femoral vein, and 
 the branches of the anterior crural 
 nerve under the fascia lata. To 
 expose these satisfactorily will re- 
 
 A VIEW OF THE ANTERIOR CRURAL NERVE AND BRANCHES. 1. Place of emer- 
 gence of the nerve under Poupart's ligament. 2. Division of the nerve into 
 branches. 3. Femoral artery. 4. Femoral vein. 5. Branches of obturator nerve. 
 6. Nervus saphenus. 
 
504 THE LOWER EXTREMITY. 
 
 quire time and patience. They should be carefully studied 
 before their dissection is commenced ; and when begun the 
 scissors as well as the scalpel and the hooks will be brought 
 in requisition in the removal of the areolar tissue and the 
 adipose substance in which they are imbedded. 
 
 The femoral artery and vein have already been exposed 
 in the infundibuliform sheath. The anterior crural nerve 
 should be sought in the sulcus formed by the iliacus and 
 psoas muscles ; and when found it should be raised upwind 
 made tense, so that the direction of its branches may be dis- 
 tinctly seen and more readily traced. 
 
 It is better to follow out the principal branches of the 
 crural nerve before commencing the dissection of the vessels. 
 This is readily done with the point of the scalpel, when they 
 are rendered tense, separating them partly by cutting and 
 partly by tearing. They consist of cutaneous and muscular 
 branches. The former were described after they became 
 subcutaneous in connection with the superficial fascia. The 
 middle cutaneous was divided in raising the sartorius. The 
 internal cutaneous descends to the outer side of the artery 
 three or four inches, and then perforates the fascia lata. In 
 this part of its course it gives off several cutaneous filaments, 
 some small branches to the sartorius and to the sheath of the 
 femoral vessels, and others to anastomose with the saphenous 
 and obturator nerves. The saphenous nerve passes down on 
 the outer side of^the artery, but leaves it when the artery enters 
 the popliteal region ; it then proceeds to the inner side of the 
 knee-joint and becomes subcutaneous. In the deep part of 
 its course it gives off some cutaneous and muscular branches 
 and also filaments to anastomose with other nerves. 
 
 The muscular branches require no particular description. 
 They will be found supplying the muscles on the outer side 
 and fore part of the thigh; also, the pectineus, and in part 
 the adductor longus, on the inner side. A large branch 
 goes to the lower part of the vastus internus, which has been 
 called the short saphenous nerve. 
 
 The FEMORAL ARTERY, Fig. 206 (14), commences at a 
 point a little to the inner side of the middle of Poupart's liga- 
 ment, and extends to the junction of the middle and lower 
 thirds of the thigh, when it passes through a tendinous 
 canal formed by the adductor magnus and the vastus inter- 
 nus, to enter the popliteal space. 
 
ANTERIOR PART OF THE THIGH. 505 
 
 The femoral artery is accompanied by the FEMORAL 
 VEIN, which is at first placed to its inner side and on the 
 same plane, but soon gets behind, and in the last part of its 
 course, a little to the outer side of it. The saphenous nerve 
 lies close to the outer side of it, except at its upper part. 
 Small nervous twigs are usually met with either accompany- 
 ing the artery, crossing it, or twining around it. 
 
 The branches of the femoral artery to be examined next 
 are the inferior external pudic and the profunda, or the deep 
 femoral artery. Several small branches in the groin have 
 already been dissected. 
 
 The inferior external pudic, Fig. 206 (ie), arises near the 
 profunda, sometimes from the profunda itself, passes inwards 
 over the femoral vein below its junction with the saphenous, 
 and the pectineus muscle to the ramus of the pubes, and 
 thence to the scrotum, in the male, or to the labium exter- 
 num in the female. It perforates the fascia lata near the 
 pubic bone. 
 
 The ARTERIA PROFUNDA, Fig. 213 (is), arises from the 
 outer and back part of the femoral, about an inch and a half 
 below Poupart's ligament; the point of its origin, however, 
 varies very much in different subjects. It may not be more 
 than half an inch below Poupart's ligament, or it may be 
 two or three inches. At first it passes backwards and some- 
 what outwards, and then directly downwards to the upper 
 border of the adductor longus, beneath which it continues 
 down to the lower third of the thigh resting on the adductor 
 brevis and the adductor magnus. It perforates the last 
 named muscle and its terminal branches are distributed to 
 the back part of the thigh. In the last part of its course it is 
 very deep seated, running behind and nearly parallel with the 
 femoral artery. It gives off the following branches : 
 
 The external circumflex, Fig. 213 (i 3), which frequently 
 arises from the femoral artery, passes transversely outwards 
 behind the rectus and in front of the psoas and iliacus mus- 
 cles and divides into descending, transverse, and ascending 
 branches. This artery and its branches behind and to the 
 outer side of the rectus, can be traced more readily after that 
 muscle has been dissected. 
 
 The internal circumflex, Fig. 213 (12), which also occasion- 
 ally arises from the femoral, is usually larger than the ex- 
 
506 
 
 THE LOWER EXTREMITY. 
 
 Fig. 213. 
 
 ternal. It passes almost directly backwards between the 
 pectineus and the capsular ligament of the hip-joint. It 
 
 cannot be followed further at the 
 present time. 
 
 Besides the circumflex the pro- 
 funda gives off three or four perfo- 
 rating branches, Fig. 190 (19), Fig. 
 2 13 (is). These pass through the 
 adductor magnus and are expended 
 on the back of the thigh. Some- 
 times they arise by a common trunk. 
 
 The veins correspond to the ar- 
 teries just described. The vein 
 which accompanies the profunda 
 artery lies between it and the fe- 
 moral artery. In dissecting the 
 arteries the veins may be cut 
 away. The arteries should be pre- 
 served until the muscles have been 
 dissected, so that their relations to 
 the muscles may be observed. 
 
 The quadriceps extensor cruris 
 may now be examined. As its 
 name indicates it is a muscle hav- 
 ing four heads. These are usually 
 described as separate muscles. They 
 are named the rectus femoris, the 
 vasti externus and internus, and 
 the crureus. They cover nearly the 
 whole of the anterior and lateral 
 surfaces of the femur. 
 
 To expose these muscles divide 
 the fascia lata along the middle 
 
 A FRONT VIEW OF THE FEMORAL ARTERY, AS WELL AS OF THE PRIMITIVE AND 
 EXTERNAL ILIAC OF THE RIGHT SIDE. 1. Primitive iliac artery. 2. Internal iliac 
 artery. 3. External iliac artery. 4. Epigastric artery. 5. Internal circumflex ilii 
 artery. 6. Arteria ad cutem abdominis. 7. Commencement of the femoral just 
 under the crural arch. 8. Point where it passes the vastus internus muscle. 9. 
 Point where it leaves the front of the thigh to become popliteal. 10. Muscular 
 branch to the psoas and iliacus. 11. External pudic artery cut oif. 12. Origin 
 of the internal circumflex. 13, 13. Profunda femoris; first 13 points to origin of 
 external circumflex. 14. Muscular branch. 15, 16. Artery to the vastus externus. 
 17. Artery to the pectineus and adductors. 18. First perforating artery. 19, 19, 
 19, 19. Muscular arteries. 20. Anastomotica. 21. Superior internal articular. 22. 
 Branch of superior external articular. 23. Superior external articular. 24. Infe- 
 rior external articular. 25. Inferior internal articular. 
 
ANTERIOR PART OF THE THIGH. 507 
 
 line of the thigh down to the patella, and dissect it off from 
 the muscles by cutting in the direction of their fibres. 
 
 The KECTUS, Fig. 211 (e), arises by two short tendinous 
 heads, one from the anterior inferior spinous process of 
 the ilium, and the other from the superior margin of the 
 acetabulum. From this double origin it proceeds down- 
 wards on the front part of the thigh to the patella, into 
 which it is inserted. It is broader and thicker in the middle 
 than above or below. Its tendon at first is somewhat round, 
 but expands as it descends, and is prolonged much further 
 on the anterior than on the posterior part of the muscle, 
 while in the lower part the tendon extends further up behind 
 than it does in front. The fibres pass off obliquely on both 
 sides from the middle line, and hence it is called a penniform 
 muscle. The action of the rectus is to assist in extending 
 the leg on the thigh, or in flexing the thigh on the pelvis. 
 
 The rectus may now be divided in the middle and turned 
 upwards and downwards, and the dissection of the external 
 circumflex artery completed. 
 
 The YASTUS EXTERNUS, Fig. 211 (7), arises around the 
 base of the trochanter major, from the linea aspera, from the 
 ridge which runs from it to the trochanter, and also from 
 the external intermuscular septum of the fascia lata. It is 
 inserted into the patella and the tendon of the rectus. The 
 direction of its fibres increase in obliquity from above down- 
 wards, the upper fibres descending almost perpendicularly, 
 while the lower are nearly transverse. It is separated from 
 the crureus beneath it by vessels, nerves, and areolar tissue ; 
 this space should be observed with reference to the collection 
 of pus in it. 
 
 The YASTUS INTERNUS, Fig. 211 (s), is placed on the inner 
 side of the thigh, and is not separated by any natural divi- 
 sion from the crureus. It arises from the linea aspera and 
 from a rough line extending from the linea aspera to the 
 trochanter minor, and also from the internal intermuscular 
 septum. It is inserted into the patella and the tendon of the 
 rectus. 
 
 The crureus, Fig. 214 (i 5), arises from the anterior surface of 
 the femur, commencing above at the anterior intertrochanteric 
 ridge, and extending downwards between the origins of the 
 vasti to a short distance above the condyles. It is inserted iuto 
 
508 
 
 THE LOWEK EXTREMITY. 
 
 Fig. 214. 
 
 the tendon of the rectos and into the patella. When the cru- 
 reus is raised a fasciculus will be found going to the upper part 
 of the synovial membrane of the knee-joint. This is called 
 the subcrureus muscle. Its action is supposed to be to draw 
 the synovial membrane upwards, so that it may not be 
 pinched between the articular surfaces of the joint. It should 
 be observed that the crureus does 
 not occupy in its origin the whole of 
 the anterior surface of the femur. 
 
 The action of the vasti and crureus 
 muscles is to assist the rectus in ex- 
 tending the leg on the thigh. These 
 four muscles, it will be seen, are at- 
 tached to the tubercle of the tibia 
 through the medium of the patella 
 and the ligament of the patella. 
 
 The pectineus and the adductor 
 muscles, including the lower portion 
 of the psoas magnus and iliacus in- 
 terims, may now be examined. The 
 last-named muscles have already been 
 described. 
 
 The PECTINEUS, Fig. 214 (4, e), is 
 situated at the upper and anterior 
 part of the thigh. It arises from the 
 pectineal line, and from a triangular 
 surface in front of this line, passes 
 downwards, and is inserted into the 
 ridge which extends from the trochan- 
 ter minor to the linea aspera. 
 
 The ADDUCTOR LONGUS, Fig. 214 
 (e, 9, i o), lies on the inner side of the 
 pectineus, with which it is usually 
 
 A VIEW OP THE DEEP-SEATED MUSCLES ON THE INSIDE OF THE THIGH. 1. Os 
 ilii. 2. Capsular ligament of the hip-joint. 3. Trochanter major. 4. Origin of 
 the pectineus muscle. 5. Symphysis pubis. 6. Origin of the adductor longus. 7. 
 Insertion of the iliacus internus and the psoas magnus. 8. Insertion of the pectineus. 
 9. Middle of the adductor longus. 10. Tendinous insertion of the adductor longus. 
 11. Part of the adductor brevis seen between the pectineus and adductor longus. 
 32. Adductor magnus. 13. Aperture for the passage of bloodvessels. 14. Adduc- 
 tor magnus with opening for the femoral vessels. 15. Portion of the crureus. 16. 
 Another opening for vessels. 17, 18. Cut tendon of the quadriceps femoris. 19. 
 Ligament of the patella. 
 
ANTERIOR PART OF THE THIGH. 509 
 
 closely connected at its upper part, but separated from it below 
 by a triangular areolar interspace, in which the adductor bre- 
 vis is seen. It arises, by a narrow, flat tendon, from the spine 
 and body of the pubes, passes downwards, backwards, and 
 outwards, and is inserted into the linea aspera at the middle 
 third of the femur. Near its insertion, it is connected by 
 tendinous fibres to the adductor magnus and vastus inter- 
 nus. It is perforated by branches of the arteria profunda 
 femoris. 
 
 The pectineus and adductor longus should now be detached 
 at their origins, and carefully turned downwards for the pur- 
 pose of examining the anterior or superficial branches of the 
 obturator nerve, which are situated immediately behind these 
 muscles. 
 
 The obturator nerve, Fig. 212 (5), enters the inner and upper 
 part of the thigh through the sub-pubic canal in the obtura- 
 tor foramen. As it leaves the canal, or just before it leaves, 
 it gives off one or two twigs to the obturator externus muscle, 
 and to the hip-joint; it then divides into its superficial and 
 deep branches. The former pass in front of the adductor 
 brevis, and the latter behind it. The superficial branches are 
 distributed to the pectineus, adductor brevis, adductor longus, 
 gracilis, and the vastus internus muscles. After passing be- 
 neath the pectineus and the adductor longus, a branch pro- 
 ceeds to join the plexus formed on the inner side of the thigh 
 by branches derived from the internal cutaneous and saphe- 
 nous nerves. Yaginal branches are also sent to the femoral 
 artery. The accessory obturator nerve will be found beneath the 
 pectineus muscle. This nerve reaches the thigh by passing 
 over the brim of the pelvis near the pectineal eminence. It 
 usually anastomoses with the obturator nerve, and sends a 
 filament to the pectineus, and one to the hip-joint. The deep 
 division of the obturator nerve perforates the obturator ex- 
 ternus, to which it sends filaments. It then descends on the 
 adductor magnus, to which it is principally distributed. One 
 branch leaves this muscle and joins the femoral artery as it 
 enters the popliteal space. It terminates in articular branches 
 to the knee-joint, and to the upper and back part of the leg. 
 
 The adductor brevis and magnus muscles may now be dis- 
 sected. 
 
 The ADDUCTOR BREVIS, Fig. 214 (i i), arises from the pubes 
 
 43* 
 
510 THE LOWER EXTREMITY. 
 
 below its spine, and to the outer side of the origin of the 
 gracilis. It passes downwards, outwards, and a little back- 
 wards, and is inserted into the upper part of the linea aspera. 
 The adductor brevis should now be raised and turned 
 downwards, and the deep branch of the obturator nerve, and 
 the branches of the obturator artery, traced. 
 
 The ADDUCTOR MAGNUS, Fig. 214 (12), is a very large 
 muscle, forming a large portion of the fleshy mass on the 
 inner and upper part of the thigh. It cannot be fully ex- 
 amined until the back part of the thigh is dissected. It 
 arises from the ramus and anterior part of the tuberosity of 
 the ischium, and from the descending ramus of the pubes. 
 Its fibres pass outwards and downwards, and are inserted into 
 the linea aspera through its entire length, and into a tubercle 
 on the inner aspect of the internal condyle of the femur. Its 
 upper fibres have nearly a transverse direction, while those 
 below increase in obliquity from above downwards. The 
 portion of the muscle which is inserted into the linea aspera, 
 is separated from that portion inserted into the condyle by 
 the femoral vessels and their sheath; its tendon is here con- 
 nected to that of the vastus internus, so as to form a tendi- 
 nous arch over these vessels as they enter the popliteal region. 
 By observing the direction of the fibres of the inner portion 
 of this muscle, it will be seen that, when it contracts, it can- 
 not compress the femoral vessels. The perforating branches 
 of the arteria profunda, with their accompanying veins, pass 
 through openings formed in the tendon of this muscle. 
 
 The action of the adductor muscles, including the pecti- 
 neus, is to approximate the lower extremities ; they will also 
 assist in rotating the thigh outwards. The pectineus and 
 adductor longus may assist in flexing the thigh on the pelvis, 
 or the pelvis on the thigh. 
 
 The obturator externus is partly brought into view when 
 the pectineus and adductor brevis are turned down. It will 
 be described in the dissection of the posterior part of the 
 pelvis and thigh. 
 
 The psoas magnus and iliacus internus muscles should now 
 be divided and reflected downwards, so as to expose in front 
 the capsular ligament of the hip-joint, Fig. 214 (2). 
 
THE GLUTEAL KEGION. 511 
 
 SECT. II. THE GLUTEAL BEGION. 
 
 This region includes those parts which are found on 
 the side and posterior part of the pelvis. To dissect it the 
 subject must be placed on its face with the pelvis raised a 
 foot or more by means of blocks. It is a matter of little 
 consequence in what direction the incisions are made for the 
 purpose of removing the integument unless it is intended to 
 remove the fascia at the same time. In this case the inci- 
 sions should be made so that the gluteus maximus muscle 
 may be exposed by cutting in the direction of its fibres. 
 
 To examine the cutaneous nerves the integument must be 
 dissected off and the nerves traced in the superficial fascia 
 and fat, which usually exists in great abundance in this 
 region. The nerves are derived from the last dorsal^ the 
 lumbar^ and the sacral. These enter the gluteal region at 
 different points. The gluteal branch of the external cuta- 
 neous nerve enters it from the anterior part of the thigh just 
 below the anterior superior spinous process of the ilium. 
 Two branches, one from the last dorsal and another from the 
 superior musculo-cutaneous, pass over the crest of the ilium, 
 the former anterior to the middle of the crest, the latter 
 more posteriorly. The posterior divisions of the last two 
 lumbar are distributed principally to the skin in the gluteal 
 region. There are two or three derived from the posterior 
 divisions of the sacral nerves ; also filaments from the lesser 
 sciatic nerve. 
 
 Beneath the superficial fascia will be found the gluteal 
 aponeurosis. This is attached above and behind to the crest of 
 the ilium, to the sacrum, and to the coccyx; in front and below 
 it is continuous with the fascia lata. It is quite thin where 
 it covers the gluteus maximus, but thick and dense over that 
 portion of the gluteus medius which is not covered by the 
 preceding muscle ; the gluteus medius arises partly from its 
 under surface; a layer of it passes beneath the gluteus 
 maximus. It is separated from the great trochanter and the 
 tuberosity of the ischium by synovial capsules. 
 
 The GLUTEUS MAXIMUS, Fig. 215 (2), is the first muscle to 
 be dissected in this region. To expose it an incision should 
 be made through the skin and fascia, if the skin has not been 
 
512 
 
 THE LOWER EXTREMITY. 
 
 Fig. 215. 
 
 THE MUSCLES OF THE GLTT- 
 TEAL AND POSTERIOR FEMORAL 
 REGIONS. 1. The gluteus ine- 
 dius. 2. The gluteus maximus. 
 3. The vastus externus, covered 
 in by fascia lata. 4. The long 
 head of the biceps. 5. Its short 
 head. 6. The semi-tendinosus. 
 7, 7. The serni-membranosus. 8. 
 The gracilis. 9. A part of the 
 inner border of the adductor 
 magnus. 10. The edge of the 
 sartorius. 11. The popliteal 
 space. 12. The gastrocnemius 
 muscle ; its two heads. The 
 tendon of the biceps forms the 
 outer hamstring; and the sarto- 
 rius, with the tendons of the 
 gracilis, semi-tendinosus, and 
 eemi-membranosus, the inner 
 hamstring. 
 
 previously removed, from near the 
 middle of the sacrum to a short dis- 
 tance below the trochanter major. 
 This incision should be made down 
 to the muscle, so that its fibres or 
 fasciculi, which are very coarse, 
 may be distinctly seen. If the fibres 
 are now made tense the student will 
 have no difficulty in exposing the 
 muscle by dissecting one flap up- 
 wards and the other downwards, 
 being careful to observe the direc- 
 tion of the fibres. This muscle arises 
 from the dorsum of the ilium above 
 and behind the superior semicircular 
 ridge, from the tubercles on the pos- 
 terior surface of the sacrum, from 
 the coccyx and the great sacro-sciatic 
 ligament. Some of its fibres also 
 arise from the aponeurosis of the 
 gluteus medius. It passes obliquely 
 downwards and outwards over the 
 trochanter major, from which its 
 tendon is separated by quite a large 
 bursa mucosa. The lower part of the 
 muscle is inserted into the rough 
 line which extends from the tro- 
 chanter major to the linea aspera. 
 The upper part is connected to the 
 fascia lata of the thigh. A bursa se- 
 parates its tendon from the vastus 
 externus, and not unfrequently 
 another one separates it from the tu- 
 berosity of the ischium. Its lower 
 border is free, and forms the lower 
 boundary of the nates or buttock, 
 while the upper border is blended 
 with the aponeurosis of the gluteus 
 medius, and can be distinguished 
 from this muscle only by observing 
 the different direction of the fibres of 
 the two muscles. When the gluteus 
 
THE GLUTEAL REGION. 
 
 513 
 
 maximus is fairly ex- 
 posed and properly stu- 
 died it should be care- 
 fully raised by detaching 
 it from its origin and 
 reflecting it downwards. 
 As it is raised, the glu- 
 teal artery and nerve, 
 and the gluteal branch- 
 es of the sciatic artery 
 and lesser sciatic nerve 
 will be found entering 
 the muscle upon its un- 
 der surface. The glu- 
 teus meclius should now 
 be dissected and studied. 
 
 The GLUTEUS MEDIUS 
 Fig. 216 (e), arises from 
 the dorsum of the ilium 
 between the middle and 
 superior semicircular 
 ridges and the crest of 
 the ilium. That portion 
 of it not covered by the 
 gluteus maximus has a 
 very thick dense aponeu- 
 rosis, from the under 
 surface of which many 
 of its fibres arise. Its 
 fibres converge to form 
 a short thick tendon, 
 which is inserted into the 
 outer part of the tro- 
 chanter major. It will 
 be observed that the di- 
 rection of the fibres of 
 this muscle, viewed in 
 relation to the hip-joint, 
 is quite different from 
 that of the fibres of the 
 preceding muscle; that 
 
 Fig. 216. 
 
 A VIEW OP THE DEEP-SEATED MUSCLES OK 
 THE POSTERIOR PART OF THE Hir-JoiNT. 1. 
 Fifth lumbar vertebra. 2. Ilio-lumbar ligament. 3. 
 Crest of the ilium. 4. Anterior superior spinous 
 process of ilium. 5. Part of the fascia lata. 6. 
 Gluteus medius. 7. Its lower and anterior por- 
 tion. 8. Pyriformis. 9. Gemelli. 10. Trochanter 
 major. 11. Insertion of the gluteus medius. 12. 
 Qu'adratus fernoris. 13. Part of the adductor 
 magnus. 14. Insertion of the gluteus maximus. 
 1 5. Vastus externus. 16. Long head of the biceps. 
 17. Semi-membranosus. 18. Semi-tendinosus. 
 19. Tuber ischii. 20. Obturator internus. 21. 
 Point of the coccyx. 22. Posterior coccygeal 
 ligament. 23, 24. Great sacro-sciatic ligament. 
 
 25. Posterior superior spinous process of ilium. 
 
 26. Posterior sacro-iliac ligament. 
 
514 THE LOWER EXTREMITY. 
 
 while those of the latter are directed generally from behind 
 forwards and downwards, those of the former are directed 
 not only from behind downwards and forwards, but from 
 above downwards, and also from before downwards and back- 
 wards. Its lower border is placed in juxtaposition with the 
 pyriformis muscle, from which some care will be requisite to 
 separate it. Its under surface is penetrated by branches of 
 the gluteal artery and nerves. This muscle should now be 
 detached from its origin and turned downwards, when the 
 gluteus minimus will be brought into view. 
 
 The GLUTEUS MINIMUS, Fig. 219 (s), arises from the dor- 
 sum of the ilium between the middle and inferior semicircu- 
 lar ridges. Its fibres converge and unite in a short tendon, 
 which is inserted into the anterior border of the trochanter 
 major. The direction of its fibres is the same as that of the 
 fibres of the gluteus medius. The capsular ligament of the 
 hip-joint is placed immediately beneath this muscle. 
 
 The action of the glutei muscles varies according as the 
 pelvis or the femur is the fixed point, also according as the 
 three muscles act together or separately. When standing on 
 one leg these muscles hold the pelvis in situ, and thus keep 
 the body in the erect position ; or they may incline it to their 
 own side, or rotate it on the head of the femur. They are 
 capable of rotating the limb inwards or outwards, also of 
 abducting or extending it. They are concerned in walking. 
 The gluteus maximus also renders tense the fascia lata. 
 
 The following vessels and nerves should now be exa- 
 mined : 
 
 The gluteal artery, Fig. 217 (i), is a branch of the internal 
 iliac. It escapes from the pelvis through the upper part of 
 the great sacro-sciatic foramen, and appears in the gluteal 
 region between the pyriformis and gluteus minimus muscles. 
 It divides into a superficial and deep branches. The super- 
 ficial branch passes forwards, and divides into several branches 
 between the glutei maximus and medius. These are dis- 
 tributed principally to the upper part of the gluteus maximus 
 and the integument of this region. The deep branches ramify 
 between the glutei medius and minimus, which muscles 
 they supply. One or more of these pass upwards and for- 
 wards to the anterior superior spinous process of the ilium, 
 where it anastomoses with the external circumflex artery, a 
 branch of the arteria profunda, and also with the external 
 
THE GLUTEAL REGION. 
 
 515 
 
 circumflex ilii, a branch of the 
 femoral artery. Other branches 
 are directed towards and above 
 the trochanter major. The glu- 
 teal nerves are divided into the 
 superior and inferior. 
 
 The superior gluteal nerve, Fig. 
 218 (2), is a branch of the lum- 
 bo-sacral cord. It accompanies 
 the gluteal artery through the 
 great sacro-sciatic foramen. It 
 divides into two principal branch- 
 es. One of these accompanies the 
 superior deep branch of the glu- 
 teal artery; the other is directed 
 downwards and forwards above 
 the trochanter major, and termi- 
 nates in the tensor vaginse femo- 
 ris muscle. These nerves supply 
 the glutei medius and minimus. 
 
 The inferior gluteal nerve comes 
 from the small or lesser sciatic 
 nerve. It consists of muscular 
 and cutaneous branches. The 
 former are distributed to the glu- 
 teus maximus; they penetrate its 
 under surface. The cutaneous 
 branches descend below the lower 
 border of the gluteus maximus, 
 where some filaments ascend to 
 
 Fig. 217. 
 
 A VIEW OF THE ARTERIES ON THE BACK OF THE BUTTOCK AND THIGH, AS WELL 
 AS ON THE BACK OF THE HAM. 1. Gluteal artery as it escapes from the pelvis. 
 2, 3, 4. Branches which it furnishes to the gluteus medius aud gluteus minimus 
 muscles. 5. Small cutaneous arteries given off by the posterior branches of the 
 sacral arteries. 6, 6. Internal pudic, from its exit from the pelvis to the root of 
 the penis. 7, 7. Sciatic artery as it escapes from the pelvis to its distri- 
 bution to the biceps and semi-tendinosus muscles, as well as its branches to 
 the gemelli, pyriformis, and quadratus femoris muscles. 8. Termination and 
 distribution of internal circumflex. 9. Profunda femoris seen in the thickness 
 of the adductors. 10. A branch to adductor longus and brevis. 11. First per- 
 forating artery, going to vastus externus. 12. Second perforating artery. 13. 
 Third perforating artery. 14. Termination of profunda femoris. 15. A branch to 
 the short head of the biceps. 16. Popliteal artery. 17, 18, 19. Its articular 
 branches. 20, 21. Gastrocnemial arteries. 
 
516 
 
 THE LOWEK EXTREMITY. 
 
 Fig. 218. 
 
 supply the integument covering this muscle, while other 
 
 filaments are distributed to the skin below it. 
 
 The sciatic artery, Fig. 217 (7, 7), is a branch of the internal 
 
 iliac. It leaves the pelvis through the lower part of the 
 
 great sacro-sciatic notch, be- 
 low the pyriformis. In the first 
 part of its course, it gives off 
 branches to the gluteus maxi- 
 mus, some of which pass through 
 the muscle, and supply the in- 
 tegument over it. One or more 
 branches, named coccygeal, usu- 
 ally perforate the great sacro- 
 sciatic ligament, and ramify on 
 the dorsum of the sacrum, and 
 in the coccygeal region. An- 
 other branch, called the comes 
 nervi ischiadici, goes to the great 
 sciatic nerve, and accompanies 
 it for some distance down the 
 thigh. The sciatic artery, after 
 giving off these branches, de- 
 scends in a line midway be- 
 tween the trochanter major and 
 tuberosity of the ischium on 
 the gemelli, the obturator in- 
 A VIEW OP THE BRANCHES OF THE ternus, and the quadratus femo- 
 
 SACRAL PLEXUS TO THE HIP AND r i s muscles, which are Supplied 
 
 -,i u i T r 
 
 Wlt) h branches derived from it. 
 
 It gives off branches to anas- 
 
 tomose with the internal oir- 
 cumflex and perforating branch- 
 
 p<5 n f ^^ artpria r>rrfnnrln 
 Ch * . 6 a 
 
 Ine internal pudic artery, Fig. 
 217 (e , 6 ), another branch of the 
 
 internal iliac, escapes from the pelvis in company with the 
 sciatic, but leaves it almost immediately to wind around 
 the spine of the ischium, and enter the perineum through the 
 small sacro-sciatic foramen. 
 
 The GREAT SCIATIC or ISCHIATIC NERVE, Fig. 218(6), is a 
 continuation of the sacral plexus. It is the largest nerve in 
 
 BACK OF THE THIGH. 1, 1. Posterior 
 saeral nerves. 2. Superior gluteal 
 nerve. 3. The internal pudie nerve 
 
 . 
 
 off the perineai cutaneous (pudendaiis 
 
 longus inferior); and 5. The ramus 
 femoralis cutaneus posterior. 6. The 
 
 great sciatic nerve. 
 
THE GLUTEAL REGION. 
 
 517 
 
 the body. It leaves the pelvis in company with the sciatic 
 artery and the lesser sciatic nerve, and descends between 
 the trochanter major and ^tuberosity of the ischium to the 
 posterior part of the thigh. Sometimes the whole, or a part 
 of it, perforates the pyriformis muscle. It usually gives off 
 one or more small articular branches to the hip-joint. As it 
 passes over the quadratus femoris, or a little below this 
 muscle, branches are sent off from it to the muscles on the 
 back of the thigh, including the adductor magnus. 
 The lesser sciatic nerve, Fig. 
 
 & 
 
 218 (4), is derived from the 
 sacral plexus. As it leaves 
 the pelvis it lies at the inner 
 side of the great sciatic nerve, 
 but gets behind it as it de- 
 scends to the back part of the 
 thigh. Besides the inferior 
 gluteal nerve, it gives off at 
 the lower part of the gluteus 
 maximus the inferior long pu- 
 dendal nerve. It then conti- 
 nues down the limb to the 
 popliteal region and the upper 
 part of the leg. The inferior 
 pudendal nerve passes for- 
 wards below the tuberosity of 
 the ischium to reach the an- 
 terior part of the scrotum. 
 
 The internal pudic and the 
 inferior hemorrhoidal nerves, 
 Fig. 218 (3), will be seen at 
 this stage of the dissection, 
 passing around the spine of 
 the ischium and through the 
 small sacro-sciatic foramen to 
 enter, in company with the 
 internal pudic artery, the pe- 
 rineum. 
 
 The following group of 
 
 small -muscles may now be 
 
 examined as they appear in 
 
 the dissection of this region. 
 
 44 
 
 Fig. 219. 
 
 THE BEEP MUSCLES OF THE GLTJTEAL 
 REGION. 1. The external surface of the 
 ilium. 2. The posterior surface of the 
 f=aerura. 3. The posterior sacro-iliac 
 ligaments. 4. The tuberosity of the 
 ischium. 5. The great or posterior sa- 
 cro-sciatic ligament. 6. The small or 
 anterior sacro-sciatic ligament. 7. The 
 trochanter major. 8. The gluteus mi- 
 nimus. 9. The pyriformis. 10. The 
 gemellus superior. 11. The obturator 
 internus, passing out of the lesser 
 sacro-sciatic foramen. 12. The gemellus 
 inferior. 13. The quadratus femoris. 
 14. The upper part of the adductor mag- 
 nus. 15. The vastus externus. 16. The 
 biceps. 17. The gracilis. 18. The se- 
 ini-tendinosus. 
 
518 THE LOWER EXTREMITY. 
 
 They will be found to occupy nearly the same plane with 
 each other and with the gluteus minimus, except the obtu- 
 rator externus. 
 
 Before commencing the dissection of them, the student 
 should be particular to see that the limb is rotated inwards 
 and fastened in this position so that the muscles shall be kept 
 tense. 
 
 The PYRIFORMIS, Fig. 219 (9), lies along the lower border 
 of the gluteus medius, and not unfrequently some care is re- 
 quired to find the line which separates them. It arises with- 
 in the pelvis from several of the spaces between the anterior 
 sacral foramina and from the contiguous portion of the ilium, 
 also from the great sacro-sciatic ligament. Its fibres con- 
 verge as they pass outwards and somewhat backwards to be 
 inserted by a round tendon into the fossa on the upper and 
 back part of the great trochanter. This muscle is sometimes 
 perforated by the great sciatic nerve, or by a portion of it. 
 
 The GEMELLUS SUPERIOR, Fig. 219 (i o), is a small muscle 
 placed immediately below the pyriformis. It arises from the 
 spine of the ischium, and, passing horizontally inwards, is 
 inserted into the trochanter major close to the pyriformis. It 
 is sometimes wanting. 
 
 The GEMELLUS INFERIOR, Fig. 219 ( 2), arises from the 
 tuberosity of the ischium near the attachment of the great 
 sacro-sciatic ligament. It is inserted also into the trochanter 
 major. It is usually larger than the gemellus superior. 
 
 The OBTURATOR INTERNUS, Fig. 219 (i i), will be found 
 placed between the two gemelli occupying the small sacro- 
 sciatic foramen. The principal part of this muscle is situated 
 within the pelvis, and will require for its complete dissection, 
 as well as that of the pyriformis, a section of the pelvic 
 parietes to be made. 
 
 It arises from the internal surface of the innominatum 
 around the obturator foramen, from the obturator ligament 
 and from the outer surface of the aponeurosis which covers 
 this muscle. Its fibres converge, pass downwards and out- 
 wards through the small sacro-sciatic foramen and terminate 
 in a tendon, which is inserted into the trochanteric or digital 
 fossa in common with the gemelli. The gemelli, especially 
 the inferior, and the obturator interims are frequently so 
 
THE GLUTEAL REGION. 519 
 
 blended together for some distance from their insertion as to 
 seem to form but one muscle. With a little care, however, 
 the student will generally be able to separate them with the 
 handle of the scalpel near the small sacro-sciatic foramen. 
 
 In passing through this foramen the tendon of the obtu- 
 rator is reflected over a trochlear surface, which, as well as 
 the tendon itself, is covered by synovial membrane and kept 
 constantly lubricated with synovial fluid. 
 
 The QUADRATUS FEMORIS, Fig. 219 (is), situated just be- 
 low the inferior gemellus, arises from the posterior border of 
 the tuberosity of the ischium, and passing horizontally out- 
 wards, is inserted into the linea quadrati, a rough line on the 
 great trochanter. It is a square-shaped muscle, having its 
 fibres nearly parallel to each other. It is separated from the 
 upper border of the adductor magnus by the internal circum- 
 flex artery, which should now be examined in the terminal 
 part of its course. This artery, by its anastomosis with the 
 sciatic, establishes a connection between the profunda femoris 
 and the internal iliac artery. 
 
 The OBTURATOR EXTERNUS is exposed posteriorly by 
 raising the quadratus femoris. It arises from the -external 
 surface of the obturator ligament, and from the bone around 
 the obturator foramen. Its fibres converge and terminate in 
 a tendon which passes horizontally outwards to be inserted 
 into the lower part of the digital fossa, just below the inser- 
 tion of the gemelli and the obturator intern us. 
 
 The action of the last six muscles is very similar. They 
 rotate the limb when it is extended, outwards, but abduct it 
 in the sitting posture. When the limb is fixed, as in stand- 
 ing on one foot, they act on the pelvis. 
 
 In raising these muscles, several small nerves will be ob- 
 served penetrating them. 
 
 The nerve for the obturator internus arises from the sacral 
 plexus, winds around the spine of the ischium, and passes 
 through the small sacro-sciatic foramen to reach the muscle. 
 
 The nerve for the quadratus femoris arises from the sacral 
 plexus, passes downwards underneath the gemelli and obtu- 
 rator internus, giving off in its course filaments to the hip- 
 joint. Before terminating in the quadratus femoris, it sends 
 
520 THE LOWER EXTREMITY. 
 
 a small branch to the gemellus inferior. The gemellns supe- 
 rior receives a nerve directly from the sacral plexus. 
 
 The obturator externus is supplied with branches from 
 the obturator nerve, which is derived from the third and 
 fourth lumbar nerves. 
 
 Having completed the dissection of the parts in the glu- 
 teal region, the student should now replace the muscles and 
 study their relations to the hip-joint and to the vessels and 
 nerves. The prominent points which can be seen or felt in 
 this region in the living subject should be observed with re- 
 ference to luxation of the head of the femur and the ligation 
 of the arteries. The exact position of the trochanter major 
 and the tuberosity of the ischium and their relations to the 
 sacrum and ilium, should be carefully noted. It will have 
 been seen that the principal arteries are the gluteal, the 
 sciatic and the internal pudic. The position of each one 
 of these vessels may readily be ascertained by observing its 
 relations to the posterior inferior spinous process of the ilium, 
 the tuberosity of the ischium, and the trochanter. 
 
 As the dissection of the ligaments of the vertebral column 
 should be made in connection with those of the pelvis, and 
 as this cannot well be done until the external parts of the 
 pelvis have been dissected, the dissection of the hip-joint is 
 included with that of the others. 
 
 DISSECTION OF THE HIP-JOINT. 
 
 The hip-joint is formed by the acetabulum of the os inno- 
 minatum and the head of the femur. It is a ball and socket 
 joint. At the lower part of the acetabulum is a notch occu- 
 pied by the ligamentum teres and by the vessels that enter 
 the joint; just above this notch, and in the bottom of the 
 cavity, there is a depression occupied by adipose substance 
 and loose sy no vial membrane ; the rest of the acetabulum is 
 covered by cartilage. The head of the femur forms the seg- 
 ment of about four-fifths of a globe. It is covered by car- 
 tilage, except a small spot just below its centre, which gives 
 attachment to the ligamentum teres. The ligaments of this 
 joint consist of the capsular, the cotyloid, the round, the trans- 
 verse, and the ilio-femoral. The last two scarcely deserve to be 
 
DISSECTION OF THE HIP-JOINT. 
 
 521 
 
 Fig. 220. 
 
 considered separate ligaments; the transverse properly be- 
 longs to the cotyloid, and the ilio-femoral to the capsular. 
 
 The CAPSULAR OR ORBICULAR LIGAMENT, Fig. 220 (s), 
 like that of the shoulder-joint, completely surrounds the ar- 
 ticulation ; its fibres are not, however, like those of that liga- 
 ment, intermixed with the tendons of surrounding muscles. 
 Above and in front it is thicker and stronger than it is 
 behind and below. Externally it is composed of longitu- 
 dinal fibres which are parallel to each other, and internally 
 of fibres that run in different directions, and interlace with 
 each other ; by this arrangement of its fibres the strength of 
 the ligament is very much increased. Its superior attach- 
 ment embraces the circum- 
 ference of the acetabulum, 
 from the margin of which, 
 excepting the portion formed 
 by the transverse ligament, 
 its fibres are prolonged for 
 some distance on the bone; 
 its inferior attachment sur- 
 rounds the neck of the femur, 
 but not so as to include the 
 whole of it within the joint ; 
 the principal part excluded is 
 situated between the trochan- 
 ters and above the posterior 
 intertrochanteric ridge. This 
 should be noticed with refer- 
 ence to fractures, as it allows 
 of a fracture of the neck oc- 
 curring partly within and 
 partly without the capsular 
 ligament ; in which case, by 
 proper treatment, osseous 
 union may be obtained. 
 
 The length of the inner and ment. 3. The ilio-vertebral ligament. 
 Inwpr narf nf tliA lio-ammnf 4 - The anterior sacro-iliac ligament. 5. 
 
 ITS oi tne ligament The obturator i igame nt. 6. Poupart's 
 
 IS greater than the distance ligament. 7. Gimbernat's ligament. 8. 
 
 between the Corresponding The capsular ligament of the hip-joint. 
 
 n 9. The ilio-femoral or accessory liga-- 
 
 pomts oi attachment; hence ment. 
 
 44* 
 
 THE LIGAMENTS OP THE PELVIS AND 
 HIP-JOINT. 1. The lower part of the an- 
 terior common ligament of the vertebrae, 
 extending downwards over the front of 
 the sacrum. 2. The sacro- vertebral liga- 
 
522 THE LOWER EXTREMITY. 
 
 there is generally a looseness in this part of the ligament 
 which admits of a proportionate degree of abduction of the 
 limb. When the capsular ligament is divided, there will be 
 observed fibres, intermixed with areolar tissue, extending 
 from the root of the cervix to the margin of the articular 
 surface of the head of the bone; they seem to be a con- 
 tinuation of the fibres of the capsular ligament reflected 
 over the cervix, for which they form, with the areolar tissue, 
 quite a thick sheath or covering, especially on the upper 
 and anterior part of it. In a fracture of the neck within the 
 capsule this fibro-areolar tissue might, no doubt, contribute 
 largely to the formation of an osseous union. It would not 
 only furnish a nidus in which callus might be formed, but 
 it would be a medium for the transmission of vessels to the 
 head of the bone; in the latter case it would co-operate with 
 the ligamentum teres. 
 
 The ilio-femoral or accessory ligament, Fig. 220 (9), consists 
 of a fasciculus of fibres, which arises from the anterior infe- 
 rior spinous process of the ilium, passes obliquely downwards 
 and inwards, and, spreading out, is inserted into the anterior 
 intertrochanteric ridge. It strengthens that portion of the 
 capsular ligament to which it corresponds. On the inner 
 side of this fasciculus an opening is sometimes noticed which 
 forms a communication between the bursa that is placed 
 beneath the psoas and iliacus inter nus muscles and the cavity 
 of the joint. 
 
 The COTYLOID LIGAMENT, Fig. 221 (e), surrounds the 
 margin of the acetabulum or cotyloid cavity. It is of a tri- 
 angular form, presenting three sides ; one of these, the base, 
 is adherent to the bone ; the other two are covered by syno- 
 vial membrane, and correspond, the one with the head of the 
 femur, and the other with the capsular ligament. It is not a 
 proper ligament, but a fibre-cartilage, the cartilage increasing 
 in quantity from the apex or free edge to the base, where 
 there is but little fibrous tissue. It is separated by a groove 
 from the articular cartilage which lines the acetabulum. The 
 fibrous portion of it is continued across the notch at the 
 lower part of the cavity; this part of the cotyloid ligament, 
 together with other fibres that arise from the sides of the 
 notch, constitute the TRANSVERSE LIGAMENT. By means of 
 this arrangement, the notch is converted into a foramen for 
 
DISSECTION OF THE HIP-JOINT. 523 
 
 the transmission of vessels to the interior of the joint. What 
 is called the transverse ligament is essentially a part of the 
 cotyloid ligament; the addition of a few fibres which interlace 
 with each other, and the fact of its subtending the notch 
 does not entitle it to be considered a distinct ligament. The 
 cotyloid ligament increases the depth of the acetabulum, and 
 diminishes the diameter of its orifice by the edge being in- 
 clined inwards towards the centre; this constriction is seen 
 
 221. 
 
 LIGAMENTS OF THE PELVIS AND HIP-JOINT. THE VIEW is TAKEN FROM THE 
 SIDE. 1. The oblique sacro-iliac ligament. The other fasciculi of the posterior 
 sacro-iliac ligaments are not seen in this view of the pelvis. 2. The great sacro- 
 sciatic ligament. 3. The small sacro-sciatic ligament. 4. The great sacro-sciatio 
 foramen. 5. The small sacro-sciatic foramen. 6. The cotyloid ligament of the 
 acetabulum. 7. The ligamentum teres. 8. The cut edge of the capsular ligament, 
 showing its extent posteriorly, as compared with its anterior attachment. 9. The 
 obturator membrane only partly seen. 
 
 by the retention of the head of the femur in the cavity after 
 the capsular ligament has been completely severed. 
 
 The INTERARTICULAR LIGAMENT, or LIGAMENTUM TERES, 
 Fig. 221 (?), extends from the depression situated just be- 
 low the centre of the head of the femur to the cotyloid notch, 
 to the edges of which it is attached by two distinct fasciculi. 
 It is not round, but of a triangular form, its narrow end 
 being attached to the femur. It is from an inch to an inch 
 
524 THE LOWER EXTREMITY. 
 
 and a quarter in length; the head of the femur may be 
 luxated downwards without this ligament being ruptured, 
 but not upwards. It is loosely covered by synovial mem- 
 brane. The ligament varies very much in size in different 
 subjects. Sometimes it is entirely absent. Its principal use 
 seems to be to conduct bloodvessels to and from the head of 
 the femur, to the proper nutrition of which its presence is 
 sometimes of the greatest importance. The depression or 
 fossa, extending upwards from the notch in the bottom of 
 the acetabulum, is occupied by a mass of fat, sometimes 
 denominated a synovial gland. It allows vessels and nerves 
 to enter the joint, and protects them against pressure from 
 the head of the femur. Although called a gland, it has none 
 of the characteristics of a gland. 
 
 The SYNOVIAL MEMBRANE of the hip-joint lines the whole 
 of the internal surface of the articular cavity, and surrounds 
 the interarticular ligament. It is sometimes prolonged, as 
 was before mentioned, into a bursa placed between the cap- 
 sular ligament and the psoas and iliacus internus muscles. 
 It not unfrequently presents folds on the neck of the femur, 
 which may take the place in part of the round ligament in 
 transmitting bloodvessels to the head of the femur. 
 
 The student should attentively observe all the prominent 
 points connected with, and in the vicinity of the hip-joint; 
 such as the crest of the ilium, the trochanter major, the pubes, 
 and the sacrum and coccyx. The relation of the trochanter 
 to the other points when the limb is placed in different posi- 
 tions, as flexed, extended, abducted, and rotated both inwards 
 and outwards, should be noted. It is in the dissecting 
 room, with the subject before him, that the student should 
 prepare himself to diagnose in diseases, fractures, and luxa- 
 tions involving the hip-joint. It is here that he can measure 
 for himself the distances between the different prominent 
 points, and note the elevations and depressions as they are 
 found in their normal condition, and then calculate the various 
 changes which may occur from disease or injuries. He should 
 be able, before he leaves the hip-joint, to place his finger on 
 any point either in front of it or behind it, on the outer 
 side or inner side of it, and specify each muscle, or any ves- 
 sel or nerve that may lie between that point and the cavity 
 of the joint. The articulation is completely surrounded by 
 muscles. Thus in front are found the iliacus internus, psoas 
 
DISSECTION OF ARTICULATIONS OF VERTEBRAE. 525 
 
 magnus, and rectus femoris ; on the inner side, the pectineus, 
 obturator externus, gracills, and the adductors ; above or 
 on the outer side, the glutei and tensor vaginae femoris 
 muscles ; behind, the pyriformis, gemelli, obturator externus, 
 and the quadratus femoris. 
 
 DISSECTION OF THE ARTICULATIONS OF THE VERTEBRA. 
 
 The vertebra are connected above to the occipital bone, 
 laterally to the ribs, and below to the pelvis. The costo- 
 vertebral articulations are described in connection with the 
 dissection of the thorax; the articulation of the vertebra with 
 the pelvis is described with the pelvic articulations. It is 
 proposed now to examine the articulations of the vertebrae 
 with each other, and with the cranium. The proper mode 
 of making the dissections will be clearly indicated by the 
 accompanying drawings. The ligaments which the vertebrae 
 have in common should be examined first. They are the 
 following : 
 
 The ANTERIOR COMMON VERTEBRAL LIGAMENT, Fig. 220 
 ( i ), is placed in front and on the sides of the bodies of the 
 vertebra3, extending from the axis to the sacrum. It presents 
 a pearly white appearance, is thicker in the dorsal than in the 
 cervical or lumbar regions, and divided into a central and 
 two lateral bands, the latter being separated from the former 
 by a series of foramina on each side, for the transmission of 
 vessels, especially veins. It adheres very closely to the inter- 
 vertebral substance and margins of the bodies of the verte- 
 brae, while it is very loosely connected to the transverse 
 grooves on the bodies. It is composed of fibres which vary 
 in length, diminishing from the superficial to the deep-seated; 
 the latter extend merely from one vertebra to another, while 
 the former pass over four or five vertebrae. It is thicker 
 where it corresponds to the grooves on the bodies of the ver- 
 tebrae than it is elsewhere. The tendons of several muscles 
 are blended more or less with it in different sections of the 
 vertebral column. 
 
 The POSTERIOR COMMON VERTEBRAL LIGAMENT, Fig. 
 222 (s), is placed in the anterior part of the spinal canal, 
 
526 
 
 THE LOWER EXTREMITY. 
 
 Fig. 222. 
 
 A POSTERIOR VIEW OF 
 THE BODIES OF THREE DOR- 
 SAL VERTEBRA, CONNECT- 
 ED BY (1, 1), THEIR INTER- 
 VERTEBRAL SUBSTANCE. 
 The laminae (2, 2) have 
 been sawn through near the 
 bodies of the vertebrae, and 
 the arches and processes 
 removed, in order to show 
 (3) the posterior common 
 ligament. A part of one 
 of the openings in the 
 posterior surface of the 
 vertebrae, for the transmis- 
 sion of the vena basis ver- 
 tebrae, is seen at 4, by the 
 side of the narrow and 
 unattached portion of the 
 ligament. 
 
 extending from the occiput to the sac- 
 ram. It is narrower opposite the body 
 of each vertebra than it is opposite to 
 the intervertebral substance. It is 
 thicker and more compact than the an- 
 terior ligament ; its connection, however, 
 with the bodies of the vertebras and the 
 intervening fibre-cartilage is nearly the 
 same as that of the anterior. A plexus 
 of veins with areolar tissue separates it 
 from the body of each vertebra. It 
 diminishes in width from above down- 
 wards. The length of its fibres vary 
 in the same manner as they do in the 
 preceding ligament. The dura mater 
 adheres loosely to its posterior sur- 
 face, being connected to it by areolar 
 tissue. 
 
 The INTERVERTEBRAL SUBSTANCE or 
 LIGAMENTS, Fig. 223, Fig. 224, are placed 
 between the bodies of all the vertebras 
 except the first two. Each one consists 
 of fibro-cartilage which has the form of 
 the space that it occupies. As the 
 bodies of the vertebras vary in shape 
 so does the intervertebral substance. 
 It is usually thicker in the centre than 
 at the circumference. It adheres so 
 closely to the bone that the latter will 
 break before the former will separate from it. It also pos- 
 sesses great strength in itself. Each one consists of lamellaa 
 which are more numerous in front and on the sides, in the 
 cervical and lumbar regions, than behind ; the reverse is true 
 in the dorsal region ; they are thicker before than behind in 
 the two regions first-named, while the opposite is true in the 
 dorsal region. The anterior convexities of the column in 
 the cervical and dorsal regions are said to be due principally 
 to the thickness of the intervertebral substance, while the 
 concavity in the dorsal region is attributed to the vertebras. 
 The hea'ds of the ribs articulate, Fig. 144 (4), with the inter- 
 
DISSECTION OF ARTICULATIONS OF VEETEBK^. 527 
 
 vertebral substance, which also 
 vertebral foramina. 
 
 If a section of the interverte- 
 bral substance be made, it will 
 be found to consist, Fig. 224 (3), 
 principally of a soft pulpy sub- 
 stance in the centre, and of thin 
 layers or laminae of fibre-car- 
 tilage externally. The general 
 arrangement of the laminae are 
 concentric, one being placed 
 within another ; some of them 
 interlace with each other. They 
 are connected together by fibres, 
 which extend from one lamina 
 to another. In proceeding from 
 the circumference towards the 
 centre, the number and com- 
 pactness of the laminae dimi- 
 nish, the pulpy matter and 
 
 assists in forming the inter- 
 Fig. 223. 
 
 A LUMBAR VERTEBRA, WITH A HORI- 
 ZONTAL SECTION OP INTERVERTEBRAL 
 SUBSTANCE (1, 1), ABOVE IT. At the 
 circumference (1, 1), the concentric ar- 
 rangement of the layers of the latter 
 is shown, and in the middle (2) the 
 pulpy substance is indicated. 
 
 Fig. 224. 
 
 A VERTICAL SECTION OF TWO VERTEBRA, AND THE SUBSTANCE INTERPOSED BE- 
 TWEEN THEIR BODIES. The direction of the fibres of the intervertebra.1 substance 
 is displayed. 1,1. Fibres curved outwards. 2,2. Those curved inwards. 3. Pulpy 
 substance in the middle. 
 
 areolar tissue taking the place of them. There are fewer 
 of them behind than in front and on the sides. The 
 fibres which compose the laminae are firmly attached above 
 
528 
 
 THE LOWER EXTREMITY. 
 
 Fig. 225. 
 
 Two -LUMBAR VERTEBRAE WITH THE 
 INTERVERTEBRAL SUBSTANCE ARE 
 SEEN FROM BEFORE. By removing a 
 portion of one layer (1) of the latter, 
 another layer (2), is partly exposed, 
 and the oblique direction of their 
 fibres is made manifest. 
 
 and below to the vertebrae, but not at opposite points, as 
 
 they have, especially those of 
 the outer laminae, an oblique 
 direction, Fig. 225 (1,2); they 
 extend from the right to the left 
 or from the left to the right, ac- 
 cording as they are on the right 
 side or left side of the median 
 line, and according to the lamina 
 that is examined, as in every 
 alternate one their direction is 
 reversed, so that the fibres of any 
 two contiguous laminae decus- 
 sate with each other. They are 
 also curved, Fig. 224 (1,2), those 
 situated externally, outwards, 
 and those internally inwards. 
 When the spine is lengthened 
 and the vertebrae separated fur- 
 ther from each other, both the obliquity and the curvature of 
 the fibres are diminished. The same thing takes place on 
 the side of the convexity when the spine is bent, and also on 
 one side or the other when the spine is twisted. 
 
 The central pulpy matter is constantly compressed, as is 
 shown when a vertical section of two vertebras including the 
 intervertebral substance is made, it immediately forming a 
 projection beyond the surrounding cut surface. The same 
 fact is shown by pushing an awl in between two vertebrae, 
 when it will be forced partly back again. The expansion 
 will be greater when the preparation has been for some time , 
 macerated or soaked in water. The property of elasticity 
 which it possesses in so large a degree is an exceedingly 
 important element in the construction of the vertebral 
 column. 
 
 The intervertebral substance is more abundant between 
 the cervical and lumbar vertebrae than between the dorsal, 
 hence these portions of the column possess a greater degree 
 of mobility than the dorsal. In the aggregate, this substance 
 forms about one-fourth part of the length of the spine be- 
 tween the axis and the sacrum. 
 
 In old age the intervertebral substance possesses less elas- 
 ticity, being dryer and less in bulk. The reverse is true in 
 
DISSECTION OF ARTICULATIONS OF VERTEBRA. 529 
 
 the young. The uses of this substance in the spinal column 
 will be readily understood when its structure has been pro- 
 perly examined. While it assists in forming the parietes of 
 the spinal canal, the intervertebral foramina, and the costo- 
 vertebral articulations, and while it holds the bodies of the 
 vertebrae securely in their proper place and diminishes the 
 force of shocks transmitted to the brain, it allows a sufficient 
 degree of mobility to every part of the column in which it 
 is found, and, at the same time, prevents any undue motion 
 taking place in it. 
 
 The connection of the vertebrae by their oblique processes 
 is very different from that which has been observed between 
 the bodies. The oblique processes have articular facets, 
 which are covered by a thin layer of cartilage and by 
 synovial membrane, and articulate with those of the adjacent 
 vertebrae. They are connected by imperfect capsular liga- 
 ments, which are rather longer in the neck than in the dorsal 
 and lumbar regions. 
 
 The LIGAMENTA SuB-FLAVA, Fig. 226 (i), are composed of 
 yellow elastic fibres, arranged in 
 dense, compact laminae, which oc- Fig. 226. 
 
 cupy the spaces between the arches 
 or laminae of the vertebrae. The 
 fibres are longer than the spaces 
 between the arches, for they extend 
 a short distance on the anterior 
 surface, of the laminae. They form 
 the parietes of the spinal canal be- 
 tween the arches as far forwards as 
 the roots of the transverse pro- 
 cesses. They are thicker posteriorly 
 than laterally, and more distinct in 
 the lower than in the upper part of 
 the column. They are not found 
 in the space between the occiput 
 and the atlas, or between the atlas 
 and the axis. They are strong and 
 elastic; they assist the muscles in 
 keeping the column in an erect position and in restoring it 
 to this position when it has been flexed. 
 
 The SUPRA-SPINOUS LIGAMENT, Fig. 145 (1.1). connects 
 45 
 
 AN INTERNAL VIEW OP THE 
 ARCHES OP THREE VERTEBRAE. 
 To obtain this view the laminao 
 have been divided through their 
 pedicles. 1. One of the liga- 
 nienta subflava. 2. The capsu- 
 lar ligament of one side. 
 
530 THE LOWER EXTREMITY. 
 
 the ends of the spinous processes of the vertebrae, including 
 the occipital bone above, and the sacrum below. Between the 
 occiput and the seventh cervical vertebra it forms what is 
 called the ligamentum nuchse. This is connected by slips to 
 the spinous processes of all the cervical vertebrae except the 
 first. It varies much in size. Situated in the median line, 
 it is connected with the tendons of several muscles in this 
 region, and can be distinguished from them only by the 
 direction of its fibres. The same is true of the supra-spinous 
 ligament below this, which is much larger and stronger in 
 the lumbar region than in the dorsal. 
 
 The INTER-SPINOUS LIGAMENTS extend between the spinous 
 processes of the dorsal and lumbar vertebrae. They are thin 
 and membranous in the dorsal region, but quite thick and 
 strong in the lumbar region. They are intimately connected 
 with the tendons of the extensor muscles of the back. 
 
 The INTER-TRANSVERSE LIGAMENTS are found only in the 
 lower part of the dorsal region and in the lumbar region. 
 Their use seems to be as much to give attachment to the 
 muscles as to connect the bones. These, as well as the ob- 
 lique, the supra- spinous, and the inter-spinous, are inelastic. 
 
 The occipital bone is connected to the atlas by an anterior 
 and a posterior ligament, and two on each side. 
 
 The ANTERIOR OCCIPITO-ATLANTAL LIGAMENT, Fig. 227 
 (1,2), may be said to consist of two, a round or superficial, 
 and a broad or deep-seated one. Both of them extend from 
 the anterior border of the occipital foramen to the anterior 
 arch of the atlas. The superficial consists of a thick, strong, 
 round fasciculus, which forms quite an elevation in the me- 
 dian line; it is inserted into the tubercle on the anterior 
 arch of the atlas. The deep-seated is broader than, but not 
 so thick, as the superficial. 
 
 The POSTERIOR OCCIPITO-ATLANTAL LIGAMENT, Fig. 228 
 (3), connects the posterior margin of the occipital foramen 
 to the posterior arch of the atlas. It is broad and thin. 
 The vertebral arteries and sub-occipital nerves pass through 
 it. The dura mater adheres closely to its inner surface. 
 
 Each condyle of the occipital bone is joined to the cor- 
 responding oblique process of the atlas by a CAPSULAR LIGA- 
 MENT, Fig. 228 (4,4.) This ligament is much thicker ex- 
 
DISSECTION OF ARTICULATIONS OF VERTEBRAE. 531 
 
 ternally and anteriorly than it is elsewhere. It allows con- 
 siderable motion to these articulations. A synovial membrane 
 
 Fig. 227. 
 
 AN ANTERIOR VIEW OF THE LIGAMENTS CONNECTING THE ATLAS, THE Axis, AND 
 THE OCCIPITAL BONE. A TRANSVERSE SECTION HAS BEEN CARRIED THROUGH THE 
 BASE OP THE SKULL, DIVIDING THE BASILAR PROCESS OP THE OCCIPITAL BONE 
 AND THE PETROUS PORTIONS OP THE TEMPORAL BONES. 1. The anterior round 
 occipito-atlantal ligament. 2. The anterior broad occipito-atlantal ligament. 3. 
 The commencement of the anterior common ligament. 4. The anterior atlanto-axoid 
 ligament, which is continuous inferiorly with the commencement of the anterior 
 common ligament. 5. One of the atlanto-axoid capsular ligaments; the one on the 
 opposite side has been removed, to show the approximated surfaces of the articular 
 processes (6). 7. One of the occipito-atlantal capsular ligaments. The most exter- 
 nal of these fibres constitute the lateral occipito-atlantal ligament. 
 
 lines the inner surface of each ligament, and covers the 
 articular cartilage inclosed by the ligament. 
 
 Fig. 228. 
 
 THE POSTERIOR LIGAMENTS OF THE OCCIPITO-ATLOID, AND ATLANTO-AXOID ARTI- 
 CULATIONS. 1. The atlas. 2. The axis. 3. The anterior ligament of the occipito- 
 atlantal articulation. 4, 4. The capsular and lateral ligaments of this articulation. 
 5. The posterior ligament of the atlanto-axoid articulation. 6, 6. Its capsular 
 ligaments. 7. The first of the ligamenta subflava, passing between the axis and the 
 third cervical vertebra. 8, 8. The capsular ligaments of those vertebrae. 
 
532 THE LOWER EXTREMITY. 
 
 The LATERAL OCCIPITOATLANTAL LIGAMENT, Fig. 228 
 (4), connects the transverse process of the occipital bone to 
 the transverse process of the atlas. It is quite a thick, strong, 
 ligamentous cord. By its connection with a ligamentous 
 fasciculus, which is attached to the petrous portion of the 
 temporal bone, a fibrous canal is formed for the transmission 
 of the large vessels and nerves at the base of the skull. 
 
 The occipital bone is connected to the axis by four liga- 
 ments; three of which are attached to the odontoid process, 
 and one to the body of the axis. 
 
 Fig. 229. 
 
 THE UPPER PART OF THE VERTEBRAL CANAL, OPENED FROM BEHIND IN ORDER TO 
 SHOW THE OCCIPITO-AXOID LIGAMENT. 1. Tho basilar portion of the sphenoid 
 bone. 2. Section of the occipital bone. 3. The atlas, its posterior arch removed. 
 4. The axis, the posterior arch also removed. 5. The occipito-axoid ligament, ren- 
 dered prominent at its middle by the projection of the odontoid process. 6. Lateral 
 and capsular ligaments of the occipito-atlantal articulation. 7. Capsular ligament 
 between the articulating processes of the atlas and axis. 
 
 The OCCIPITO-AXOID LIGAMENT, or APPARATUS LIGA- 
 MENTOSUS COLLI, Fig. 229 (s), is placed beneath the dura 
 inater, and extends from the lower part of the basilar fossa 
 of the occipital bone downwards to the body of the axis, 
 where the central part of it is continuous with the posterior 
 common spinal ligament. The lower part of this ligament 
 may be divided into three fasciculi or bands, two of which 
 are situated laterally, and are continued down to the third 
 or fourth cervical vertebrae. 
 
 The ODONTOID or MODERATOR LIGAMENTS connect the 
 odontoid process with the sides of the occipital foramen. 
 They consist of thick, round fibrous cords, one on each side, 
 which have an oblique direction from below upwards and 
 
DISSECTION OF ARTICULATIONS OF VERTEBRA. 533 
 
 outwards. They have been called moderator or check liga- 
 ments, from their regulating the rotatory motion of the head 
 on the axis. What is called the middle ligament consists of a 
 few ligamentous fibres that pass from the summit of the odon- 
 toid process to the anterior border of the occipital foramen. 
 
 The atlas and axis are connected together by five liga- 
 ments. 
 
 The ANTERIOR, Fig. 227 (4), and POSTERIOR, Fig. 228 (5), 
 ATLANTO-AXOID LIGAMENTS are placed between the ante- 
 rior and posterior arches of the atlas and the corresponding 
 portions of the axis. The anterior is attached below, to the 
 base of the odontoid process, and on each side of it, to the 
 body of the axis, where it is continuous with the anterior 
 common ligament. The posterior ligament corresponds to 
 the ligamenta sub-flava; below it is attached to the upper 
 borders of the laminae of the axis. 
 
 Fig. 230. 
 
 A POSTERIOR VIEW OP THE LIGAMENTS CONNECTING THE ATLAS, THE Axis, AND 
 THE OCCIPITAL BONE. THE POSTERIOR PART OP THE OCCIPITAL BONE HAS BEEN 
 SAWN AWAY, AND THE POSTERIOR ARCHES OF THE ATLAS AND AXIS REMOVED. 1. 
 The superior part of the occipito-axoid ligament, which has been cut away in order 
 to show the ligaments beneath. 2. The transverse ligament of the atlas. 3.4. The 
 ascending and descending slips of the transverse ligament, which have obtained for 
 it the title of cruciform ligament. 5. One of the odontoid ligaments; the other 
 ligament is seen on the opposite side. 6. One of the occipito-atlantal capsular liga- 
 ments. 7. One of the atlanto-axoid capsular ligament?. 
 
 There are two CAPSULAR LIGAMENTS, Fig. 230 (7), one 
 for the oblique processes on each side. Each is composed 
 of straight and oblique fibres, and is thicker anteriorly 
 than at any other part. They are of sufficient length to 
 admit of rotatory, as well as several other movements, to 
 the head. They are lined by synovial membranes, which 
 
 45* 
 
534: THE LOWEE EXTREMITY. 
 
 also cover the articular cartilages found on the oblique pro- 
 cesses. 
 
 The articulation of the odontoid process with the anterior 
 arch of the atlas consists of a small concave facet on the former, 
 and a corresponding convex one on the latter. Both of these 
 are covered with cartilage and synovial membrane; they are 
 also surrounded by a few ligamentous fibres, which form a 
 sort of capsular ligament. 
 
 Fig. 231. 
 
 A VIEW OP THE ATLAS PROM ABOVE. SHOWING THE TRANSVERSE LIGAMENT, 
 WITH FRAGMENTS OP ITS APPENDAGES. 1. The space for the odontoid process. 2. 
 The transverse ligament. 3. Space for the spinal cord. 4, 4. Articular processes j 
 on the left one a remnant of the capsular membrane is seen. 
 
 Posteriorly, the odontoid process articulates with the TRANS- 
 VERSE LIGAMENT, Fig. 231 (2). This ligament consists of a 
 strong fasciculus of fibres which are attached to the inner 
 sides of the lateral masses of the atlas. Its connection with 
 the odontoid process is similar to that between the latter and 
 the anterior arch of the atlas, a smooth concave articular 
 facet being found on the anterior surface of the ligament, and 
 a corresponding one on the posterior surface of the process. 
 The synovial membrane, which lines this cavity, extends 
 upwards on the process to near its summit. The ring, that 
 is formed by the parietes of these articulations, has a smaller 
 orifice below than above, being adapted to the shape of the 
 odontoid process, so that the process will be retained in situ 
 after all the other connections between the atlas and axis, or 
 between these and the occipital bone have been cut away. 
 From the upper edge of the transverse ligament a layer of 
 fibres passes upwards, to be inserted into the anterior margin 
 of the occipital foramen ; and another layer of fibres from 
 the inferior margin descends to be attached to the axis. The 
 term cruciform has been applied to the transverse ligament, 
 including the vertical fibres attached to its two borders. 
 
DISSECTION OF ARTICULATIONS OF PELVIS. 535 
 
 DISSECTION OF THE ARTICULATIONS OF THE PELVIS. 
 
 The pelvis is articulated above with the vertebral column, 
 and below with the femora. The degree of mobility allowed 
 by these articulations is very different. Between the bones 
 of the pelvis, except between the sacrum and coccyx, no mo- 
 tion is required, unless it be in the female during parturition. 
 
 The sacro-vertebral articulation is formed by the last lumbar 
 vertebra and the sacrum. With the exception of the sacro- 
 vertebral and ilio- vertebral ligaments, the connecting media 
 are the same as between the different vertebrae. 
 
 The SACRO-VERTEBRAL LIGAMENT, Fig. 220 (2), is of a 
 triangular shape, and extends from the transverse process of 
 the last lumbar vertebra to the upper or horizontal surface 
 of the corresponding ala of the sacrum. Its fibres spread 
 out towards the sacro-iliac symphysis. 
 
 The ILIO-YERTEBRAL LIGAMENT, Fig. 220 (3), of a trian- 
 gular form, extends from the transverse processes of the last 
 two lumbar vertebra to the crest of the ilium. It fills up a 
 notch that would otherwise exist at this point. Sometimes 
 there are two of these ligaments on the same side. 
 
 The sacro-coccygeal articulation presents two ligaments, one 
 before and the other behind; and a thin layer of cartilage 
 placed between the two bones, where a small synovial sac is 
 sometimes met with, especially in the female. 
 
 The ANTERIOR SACRO-COCCYGEAL LIGAMENT is composed 
 of irregular fibres, and is much thinner than the posterior. 
 
 The POSTERIOR SACRO-COCCYGEAL LIGAMENT, Fig. 232 
 (i o), is quite a thick, strong ligament. It extends downwards 
 over the different pieces of the coccyx, closes in the lower 
 extremity of the sacral canal, and protects the last nervous 
 cords of the medulla spinalis. 
 
 The mobility of this articulation is said to be greater in 
 the female than in the male; and in women who have borne 
 children, its mobility is preserved for a much longer period 
 of life than in those who have not. If it were not for the 
 sacro-sciatic ligaments, the motion between the sacrum and 
 coccyx would be greater than it is. 
 
 The number of coccygeal articulations vary greatly in 
 
536 THE LOWER EXTREMITY. 
 
 different subjects, and at different periods of life. Jn the 
 young subject, a thin fibre-cartilage is found between the 
 
 Fig. 232. 
 
 A POSTERIOR VIEW OP THE LIGAMENTS OP THE PELVIS. 1. Base of the Sacrum. 
 2. The coccyx. 3, 3. The crests of the ilia. 4, 4. The tuberosities of the ischia. 
 5, 5. The great sciatic notches. 6. The small sciatic notch. 7. The femur. 8, 8. 
 The posterior saero-iliac ligaments. 9. An oblique fasciculus. 10. The posterior 
 sacro-coccygeal ligament. 11. The obturator ligament. 12. The sub-pubic fora- 
 men. 13, 13. The origin of the great sacro-sciatic ligament. 14. Its insertion. 
 15. The origin of the small sacro-sciatic ligament. 16. Its insertion. 
 
 bones, while in the old the joints are most commonly oblite- 
 rated. The sacrum and coccyx are also in the old generally 
 united by osseous substance. 
 
 The sacro-iliac articulation is formed by the sacrum arid 
 ilium. The articular surfaces, from their shape, have been 
 called the auricular facets. The connecting media consist of 
 anterior and posterior fibres, and an intermediate layer of 
 cartilage, which adheres very closely to the bones. 
 
 The ANTERIOR SACRO-!LIAC LIGAMENT, Fig. 233 (7), is 
 composed of a thin layer of fibres, extending transversely 
 from one bone to the other ; they are scarcely raised above 
 the contiguous smooth surfaces. 
 
 The POSTERIOR SACRO-!LIAC LIGAMENT, Fig. 232 (s), con- 
 sists of several fasciculi, which extend from a rough surface 
 behind the auricular facet of one bone to a corresponding sur- 
 face on the other. Some of the fibres are oblique, and others 
 
DISSECTION OF ARTICULATIONS OF PELVIS. 537 
 
 are nearly transverse. One or two of the oblique fasciculi, 
 Fig. 232 (9), have been described as distinct ligaments. The 
 ligament is situated deeply in the groove formed between the 
 sacrum and ilium; it requires considerable time and patience 
 to make a satisfactory exposition of all its fibres or fasciculi. 
 A synovial membrane is sometimes found in this articulation, 
 especially in the female, while a soft yellowish substance is 
 sometimes met within it in the male. As it is occasionally 
 desirable to disarticulate the os innominatum, as in making 
 a dissection of the pelvic viscera, the student should be care- 
 ful to ascertain the exact position of the symphysis, in front, 
 and divide all the fibres of the anterior ligament, when a 
 small scalpel can be carried through the cartilage which 
 connects the two bones forming the joint. 
 
 The two following ligaments connect the sacrum and coc- 
 cyx to the ischium. They enter so largely into the formation 
 of the pelvic parietes, and sustain such important relations 
 to various parts, that the student cannot neglect to obtain a 
 thorough knowledge of them without doing great injustice 
 to himself. They should be carefully studied before he 
 attempts to make a dissection of the pelvis or the pelvic 
 viscera. Their value in the mechanism of the pelvis will be 
 observed the moment that he contrasts an articulated pelvis, 
 composed simply of the bones, with one prepared with these 
 ligaments cleaned and retained in situ. 
 
 The POSTERIOR or GKEAT SACRO-SCIATIC LIGAMENT, Fig. 
 233 (4), is of a somewhat triangular shape, with the base 
 attached to the posterior inferior spinous process of the ilium 
 and to the border of the sacrum and coccyx, and the apex to 
 the inner edge of the tuberosity of the ischium and to the 
 ramus of the same bone. The obturator fascia is connected 
 to the anterior or falciform portion of this ligament, which 
 projects a little into the perineum, and serves to protect the 
 internal pudic vessels. The posterior surface of this liga- 
 ment is occupied by the origin of a part of the gluteus maxi- 
 mus muscle, while the anterior surface is partly free, looking 
 into the pelvic cavity, and partly in apposition with the short 
 ligament. It is perforated by small foramina for the trans- 
 mission of vessels. 
 
 The ANTERIOR or SMALL SACRO-SCIATIC LIGAMENT, Fig. 
 233 (5), is attached behind to the side of the sacrum and 
 
538 
 
 THE LOWER EXTREMITY. 
 
 Fig. 233. 
 
 coccyx, and anteriorly to the spine of the ischium. Its form 
 is triangular, and its direction is nearly transverse. Pos- 
 teriorly, it is covered principally 
 by the great ligament, with which 
 its fibres are more or less inter- 
 mingled, especially at its base 
 or near the sacrum. Anteriorly, 
 it is in apposition with the coc- 
 cygeus muscle. 
 
 The great and small sacro- 
 sciatic notches, which exist in 
 the osseous pelvis, are by these 
 two ligaments converted into 
 the great and small sacro-sciatic 
 foramina, Fig. 233 (1,2). As the 
 spine of the ischium separates 
 
 A SECTION OP THE PELVIS, SHOW- the two notches, SO the small 
 
 ING THE LIGAMENTS AND SACRO- sacro-sciatic ligament separates 
 
 SCIATIC FORAMINA ON THE LEFT IN- , . ml 
 
 NER SIDE, viz: i. Great sacro-scintic the two foramina. The contents 
 
 foramen. 2. Small sacro-sciatic fora- o f these foramina require par- 
 
 S^S^wEfTiSSit: ticular notice in the dissection 
 
 cro-sciatic. 6. Symphysis pubis. 7. of the parts inside of the pelvis 
 
 Obturltor. SaCr0 " iliaC ligament * 10 ' an(1 ln tte g 1 ^ 6 ? 1 re g ion ' 
 
 The articulation formed by 
 
 the bodies of the pubic bones is designated the symphysis 
 pubis, Fig. 233 (e). The space between these bones is of a 
 cuneiform shape, the base looking forwards and downwards, 
 and the thin edge backwards and upwards. This space is 
 filled with fibro-cartilage, including sometimes an imperfect 
 synovial sac, especially in the female. The fibro-cartilage is 
 arranged in concentric layers of an elongated oval form; 
 short fibres penetrate and connect them together, except in 
 the centre and posteriorly, where a soft pulpy substance is 
 found, or the synovial sac when present. As the laminae 
 just fill the circumference of the space between the bones, 
 they are thicker or more numerous in front than behind, 
 where they project so as to form a vertical ridge; some of 
 them may be entirely deficient behind. 
 
 Surrounding this intermediate structure, ligamentous fibres 
 extend from one bone to the other. They are named accord- 
 ing to their location. Thus, we have quite a thick, strong 
 fasciculus of fibres above, passing from one bone to the other 
 and continuing some distance on their upper borders ; this 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 539 
 
 is named the superior pubic ligament. Behind, there are fibres 
 which connect the two bones together ; they do not form, 
 however, so thick a layer as the upper and anterior ones do; 
 they constitute the posterior pubic ligament. Anteriorly, there 
 is also the same arrangement of fibres, forming the anterior 
 pubic ligament. Below, the fibres interlace, and extend down- 
 wards on the rami of the pubes, and form the sub-pubic 
 ligament, which is of a triangular shape. This ligament 
 rounds off the angle formed by the rami of the pubic bones, 
 and forms the summit of the pubic arch. The symphysis 
 pubis is supposed by some to allow of a slight degree of 
 mobility in parturition. If motion takes place at all, it must 
 be so little as to produce scarcely any appreciable effect in 
 increasing the diameters of the pelvis. 
 
 The OBTURATOR LIGAMENT or MEMBRANE, Fig. 233 (i o), 
 occupies the obturator foramen. It presents an opening 
 called the sub-pubic foramen, Fig. 232 (12), in the upper part, 
 corresponding to the sub-pubic groove in the horizontal 
 ramus of the os pubis, for the transmission of the obturator 
 nerve and vessels. Its surfaces are occupied by the origins 
 of the obturator muscles. This fibrous membrane is a sub- 
 stitute for osseous structure in the parietes of the pelvis, 
 which are probably rather strengthened than weakened by- 
 it ; it may also yield somewhat in parturition, and thus facili- 
 tate the passage of the head of the child through the pelvis. 
 Another advantage said to be derived from it, is that it is 
 lighter than bone would be; the difference, however, between 
 its weight and that of a thin lamella of bone could make no 
 manifest difference. 
 
 Pouparfs and Gimlernafs ligaments, Fig. 220 (e, 7), are 
 formed by the lower border of the tendon of the external 
 oblique muscle, with the addition of some fibres which arise 
 from the anterior superior spinous process of the ilium ; they 
 are noticed in the dissection both of that muscle and of the 
 femoral region. 
 
 SECT. III. DISSECTION OF THE BACK OF THE THIGH, AND 
 OF THE HAM. 
 
 The back part of the thigh and the popliteal space should 
 be examined at the same time, commencing the dissection 
 above, and extending it down as far as the back of the 
 
540 
 
 THE LOWER EXTREMITY. 
 
 leg. With a little attention, the student will be able to 
 ascertain the best position in which to place the limb as he 
 proceeds with the dissection. To expose the long muscles 
 on the back of the thigh, the leg should be extended on the 
 thigh, and the thigh flexed on the pelvis. To remove the 
 skin, an incision may be made through it in the median line 
 of the limb, beginning at the gluteal region and terminating 
 about three or four inches below the knee-joint ; but if the 
 anterior part of the thigh has already been dissected, the in- 
 tegument may be removed, by simply reflecting it either from 
 the inner or the outer part of the limb. 
 
 The superficial fascia in these regions is merely a continua- 
 tion of the superficial fascia from the fore 
 Fig. 234. p ar t of the thigh and the pelvis. There are 
 
 no arteries that require any particular no- 
 tice in this fascia; and the only vein of suf- 
 ficient importance, and which was not seen 
 in the dissection of the anterior part of the 
 thigh, to be particularly noticed, is the ex- 
 ternal saphenous. 
 
 The external or short saphenous vein is a 
 continuation of the external dorsal vein 
 of the foot. It will be found, in this dissec- 
 tion, extending up the back part of the leg 
 in the median line, and entering the pop- 
 liteal space to open into the popliteal vein. 
 Sometimes quite a large venous trunk is 
 found going from this vein to the upper 
 part of the thigh, where it unites with a 
 branch of the internal saphenous, or of the 
 deep femoral vein. 
 
 The cutaneous nerves, Fig. 234 (.2, 2), on the 
 back part of the thigh and in the ham are 
 derived, on the inner side, from the internal 
 cutaneous, and from the internal saphenous, 
 or the obturator nerve ; on the outer side, 
 from the external cutaneous ; and in the mid- 
 dle, from the posterior femoral cutaneous. 
 
 PLAN OF THE CUTANEOUS NERVES ON THE POSTERIOR ASPECT OF THE LEFT LEG. 
 1. Inner division of the internal cutaneous nerve. 2, 2. Branches of the long or 
 internal saphenous. 3. A branch of the posterior femoral cutaneous ; the offset 
 above it in a direct line is a branch of the same nerve. 4, 6. Short or external sa- 
 phenous nerve. 5, 7. Peroneal cutaneous nerve. 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 541 
 
 The one derived from the small sciatic, and descending on 
 the back of the thigh, is called the posterior femoral cutaneous 
 branch, Fig. 235 (2, 3). It gives off external and internal 
 filaments in its course down the thigh. One of its terminal 
 branches becomes subcutaneous in the popliteal space, and 
 can be traced some distance on the back of the leg. The 
 other terminal branch does not perforate the deep fascia until 
 it reaches the back of the leg, where it usually ends by anas- 
 tomosing with the external saphenous nerve. The super- 
 ficial fascia may now be removed, when 
 the fascia lata will be exposed. This is Fi g- 235 - 
 
 continuous above with the gluteal fascia 
 or aponeurosis, on each side with the 
 fascia lata, where it joins the internal and 
 external intermuscular septa, and below 
 with the deep fascia of the leg. It forms 
 a sheath for the long muscles on the back 
 of the thigh, and stretches across the pop- 
 liteal space, so as to protect the vessels 
 and nerves in that region ; near the knee 
 it is strengthened by fibres derived from 
 the tendon of the biceps flexor and the 
 vasti muscles. 
 
 The fascia lata should now be divided 
 along the median line, and reflected to 
 each side, so as to expose the parts be- 
 neath it. Having removed the fascia lata, 
 the small or lesser sciatic nerve should be 
 traced down the thigh to the back part of 
 the leg. The following muscles may be 
 examined next, taking care not to destroy 
 the great sciatic nerve. 
 
 The BICEPS FLEXOR CRURIS, Fig. 215 
 (4, s), as its name indicates, arises by two 
 heads. The long head arises tendinous, in 
 common with the semi-tendinosus, from 
 the posterior and upper part of the tuber- 
 osity of the ischium, from the lower part 
 
 A VIKW OF THE INTERNAL POPLITEAL NERVE AND SOME OP ITS BRANCHES ON THE 
 RIGHT LEG. 1. The internal popliteal nerve. 2, 3. The terminations of the ramus 
 fotnoralis cutaneus posterior. 4, 5. The internal saphenous nerve. 6, 6. The ex- 
 ternal saphenous or communicans tibialis. 
 
 46 
 
542 THE LOWER EXTREMITY. 
 
 of which it is separated by a bursa ; the short head arises, 
 muscular, from the linea aspera and the external intermus- 
 cular septum, commencing where the insertion of the glutens 
 maxirnus ends, and extending down near to the condyle. 
 The long head and the semi-tendinosus separate from each 
 other about three inches below their common origin. The 
 two heads unite to form a round tendon, which passes down- 
 wards and outwards, and is inserted by two fasciculi into the 
 head of the fibula. The long external lateral ligament of 
 the knee-joint is placed between these fasciculi; some fibres 
 extend from one of these fasciculi to the fascia of the leg, and 
 some from the other fasciculus to the head of the tibia. 
 
 The SEMI-TENDI^OSUS, Fig. 215 (e), arises, tendinous and 
 muscular, from the tuberosity of the ischium in common with 
 the long head of the biceps, passes at first directly down- 
 wards, and then inwards, becoming tendinous a short dis- 
 tance below the middle of the thigh. Its tendon, small and 
 slender, passes around the inner side of the knee-joint, then 
 forwards, and is inserted into the tubercle of the tibia. Its 
 tendon, joined with those of the sartorius, gracilis, and semi- 
 membranosus, form what has been called the goose's foot. 
 The appropriateness of the name of this muscle will be seen 
 when the relative length of its tendon is noticed. 
 
 The SEMI-MEMBRANOSUS, Fig. 215 (7, 7), arises from the 
 posterior part of the tuberosity of the ischium, in front of the 
 biceps flexor and semi-tendinosus and behind the quadratus 
 femoris, and passes downwards and inwards to the inner and 
 posterior part of the knee-joint, where its tendon divides 
 into three processes, one of which is inserted into the apo- 
 neurosis that covers the popliteal muscle; another, pass- 
 ing under the internal lateral ligament, is inserted into the 
 inner tuberosity of the tibia; the third one forms a part of 
 the posterior ligament of the knee-joint or the ligament of 
 Winslow ; this part of it is inserted into the external con- 
 dyle of the femur. The upper tendon is quite long, flat, and 
 aponeurotic; the lower part of it consists of two laminae, from 
 the opposing surfaces of which fibres arise to form the upper 
 part of the belly of the muscle. The lower tendon is round 
 and very short. By this arrangement of the muscular bellies 
 of the semi-tendinosus and serni-mernbranosus, the symmetry 
 of the back part of the thigh is preserved, the belly of each 
 
DISSECTION" OF BACK OF THIGH AND THE HAM. 543 
 
 corresponding to the long tendon of the other. These two 
 muscles form the inner hamstring, although the sartorius and 
 gracilis are sometimes spoken of as hamstring muscles. The 
 biceps flexor forms the outer hamstring. The tendons of 
 these muscles should be studied with reference to the opera- 
 tion of tenotomy. They can be distinctly felt in the living 
 subject, becoming very prominent when the leg is partly 
 flexed on the thigh. 
 
 The actions of the three muscles just described are the same 
 as far as flexing the leg on the thigh, or keeping the axis of 
 the pelvis parallel with that of the lower limb, as when 
 standing. When the leg is partly flexed, they can rotate it 
 very little, the biceps outwards, and the other two inwards. 
 Through the connection of the semi-membranosus with the 
 posterior ligament of the knee-joint, it can draw the syno- 
 vial membrane backwards. 
 
 The arteries involved in dissecting the preceding muscles 
 are principally branches of the profunda and popliteal. Those 
 derived from the profunda are the internal circumflex and the 
 perforating branches. The internal circumflex, Fig. 217 (e), 
 reaches the back of the thigh by passing, first, between the 
 pectineus and the capsular ligament of the hip-joint, to which 
 it sends a branch through the notch at the bottom of the 
 acetabulum, and then between the quadratus femoris and the 
 adductor magnus. It divides into ascending and descending 
 Iranches; the latter of which are distributed in part to the 
 muscles just examined, and to the integument in this region; 
 the former go to the muscles on the back and lower part of 
 the pelvis, the gluteus maximus and the small rotator mus- 
 cles. This artery anastomoses with the obturator, sciatic, 
 and several others. 
 
 The perforating branches, Fig. 217 (11,12,13), vary in num- 
 ber; being sometimes two and sometimes three, besides the 
 terminal branch of the profunda. The first one perforates the 
 adductor muscles a short distance below the trochanter minor, 
 and, passing backwards partly around the shaft of the femur, 
 divides into ascending and descending branches; some of 
 which terminate in the muscles of this region, and some go 
 to supply the integument. It anastomoses above with the 
 internal circumflex, externally with the external circumflex, 
 and below with the next perforating branch. It usually sup- 
 plies the femur with its nutritious artery. The other per- 
 
544 THE LOWEK EXTREMITY. 
 
 forating branches, including the terminal branch, require no 
 particular description. They perforate the adductor muscles, 
 and are distributed in the same manner as the first, of which 
 they are sometimes branches, instead of arising directly from 
 the profunda. The branches of the popliteal, as well as the 
 popliteal itself, will be noticed at another time. 
 
 The GREAT SCIATIC NERVE, Fig. 192 (7), has been noticed 
 in the dissection of the parts within the pelvis, and alfeo in 
 the gluteal region. It enters the back part of the thigh, be- 
 neath the lower border of the gluteus maximus, and resting 
 on the quadratus femoris, being in a line midway between 
 the tuberosity of the ischium and the trochanter major. For 
 a short distance below the gluteus maximus it is subapo- 
 neurotic, having no muscle between it and the integument. 
 It then passes under the long head of the biceps, and con- 
 tinues down the thigh, being inclined a little outwards, to the 
 upper part of the popliteal space, where it divides into the 
 internal and external popliteal nerves. This division sometimes 
 takes place before it leaves the pelvis ; or it may occur at any 
 point after it leaves the pelvis. When it divides in the pelvis, 
 the upper division usually perforates the pyriformis muscle. 
 It is surrounded by a large quantity of areolar tissue, and of 
 adipose substance, if the subject be fat. Its position should 
 be noticed with reference to acupuncture, or injuries of it, 
 from whatever cause. It will be observed that it can be 
 reached below the biceps without passing through any muscle, 
 and also between that muscle and the gluteus maximus. 
 
 Having examined the main trunk, it should now be traced 
 from above downwards, to find the branches given off from 
 it. They consist of muscular and articular branches; the latter 
 go to the knee-joint; two branches are distributed to the 
 semi-membranosus ; one to the semi-tendinosus ; one to the 
 long head, and one to the short head, of the biceps ; and one 
 to the adductor magnus. These nerves, except the one to 
 the short head of the biceps, usually arise just as the sciatic 
 nerve enters the back of the thigh, sometimes coming off 
 from it by a single trunk, and afterwards dividing. The 
 adductor magnus is supplied principally by branches which 
 come from the obturator nerve ; the one that comes from the 
 sciatic penetrates the inner border of the muscle some dis- 
 tance below its origin. The branch which goes to the short 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 545 
 
 head of the biceps sometimes arises with the preceding, and 
 sometimes by itself, lower down. Those that go to the other 
 three muscles, generally run some distance before penetrat- 
 ing them, which they do on their anterior surfaces. 
 
 The posterior surface of the adductor magnus, Fig. 216 (i 3), 
 should be noticed so that a clearer idea of the muscle can be 
 obtained than could be, by simply examining it when the an- 
 terior part of the thigh was dissected. Its relations to so many 
 parts renders a knowledge of it very im- 
 portant to the student. The obturator ex- Fig. 236. 
 ternus should also be examined now more 
 thoroughly than could be done before. 
 
 The popliteal space, and its boundaries, 
 Fig. 236 (3), should next be examined. It 
 is somewhat diamond-shaped, the broadest 
 part corresponding to the knee-joint. It is 
 covered in by the integument and a strong 
 aponeurotic fascia, which is continued, as 
 was noticed before, from the fascia lata on 
 the back of the thigh. This fascia serves to 
 protect the parts in this space, and, in case 
 of aneurism of the popliteal artery, or of 
 an accumulation of pus beneath it, offers 
 strong resistance, which renders such cases 
 very painful. It is connected laterally, to 
 the condyles of the femur and to the tendons 
 of the muscles. The upper part of the space 
 is bounded, on the outer side, by the biceps 
 flexor muscle, and on the inner side, by the 
 semi-tendinosus, semi-membranosus, and 
 the adductor magnus. The lower part has, 
 on the outer side, the external head of the 
 gastrocnemius and the plantaris, and on 
 the inner side, the internal head of the gas- 
 trocnemius. The anterior boundary or the 
 floor of this space, is formed by the pop- 
 
 THE SUPERFICIAL MUSCLES OP THE POSTERIOR ASPECT OP THE LEG. 1. The 
 biceps muscle forming the outer hamstring. 2. The tendons forming the inner 
 hamstring. 3. The popliteal space. 4, 4. The gastrocnemius muscle. 5, 5. The 
 soleus. 6. The tendo-Achillis. 7. The posterior tuberosity of the os calcis. 8. 
 The tendons of the peroneus longus and brevis muscles passing behind the outer 
 ankle. 9. The tendons of the tibialis posticus and flexor longus digitorum passing 
 into the foot behind the inner ankle. 
 
 46* 
 
546 
 
 THE LOWER EXTREMITY. 
 
 liteal fossa of the femur, the posterior part of the knee-joint, 
 and the popliteus muscle, or the aponeurosis which covers it. 
 The popliteal region generally contains a considerable 
 quantity of areolar tissue and adipose substance, which ren- 
 ders the dissection of its contents difficult, 
 Fig. 237. requiring time and patience to do it in 
 
 a proper manner. The vessels consist of 
 the popliteal artery and its branches, 
 and of the accompanying veins. The 
 nerves are the internal and external 
 popliteal, and their branches. 
 
 The POPLITEAL VEIN, Fig. 240 (i), is 
 placed between the artery and the inte- 
 gument, so that it will be found in the 
 dissection before the artery. The pos- 
 terior or external saphenous vein, Fig. 
 240 (7), will also be observed entering 
 the popliteal space above the joint, and 
 usually sending off a branch which 
 passes upwards, and anastomoses with 
 the inferior perforating branch. 
 
 The large nerves are more superficial, 
 and are situated, except at the lower 
 part of the popliteal space, nearer to its 
 outer border than the artery or vein, 
 and consequently should be looked for 
 in the dissection before those vessels. 
 
 The INTERNAL POPLITEAL NERVE, Fig. 
 237 (i, 2), is the largest of the two divi- 
 sions of the great sciatic, of which it 
 seems to be a continuation ; it is nearly 
 twice the size of the external popliteal 
 nerve. The biceps flexor muscle partly 
 covers it above the knee-joint. It gra- 
 dually approaches the artery, and finally 
 crosses it and the vein. It takes the 
 name of posterior tibial nerve in the 
 leg. It gives off several branches, some 
 of which are muscular, one cutaneous, 
 and others articular. 
 The muscular branches arise from it behind the joint, and 
 
 A VIEW OF THE INTER- 
 NAL POPLITEAL AND POS- 
 TERIOR TIBIAL NERVES IN 
 THE HAM AND THE BACK 
 OF THE LEG 1, 2, indi- 
 cate the course of them; 
 the upper part of the ex- 
 ternal popliteal nerve is 
 seen to the right. 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 547 
 
 are distributed to the muscles in the upper and back part of 
 the leg. Two of them, quite large, and sometimes arising 
 by a common trunk, go to the heads of the gastrocnemius. 
 They ramify on the anterior surface of each head before 
 penetrating its substance. A smaller one goes to the plan- 
 taris, entering its inner and anterior surface ; sometimes this 
 is a branch of the preceding nerve. Another branch passes 
 downwards, and gets between the soleus and gastrocnemius 
 muscles, and, after ramifying on the posterior surface of the 
 soleus, penetrates its substance. The last muscular branch 
 goes to the popliteus ; after passing down to the lower bor- 
 der of the muscle, turns around it and passing upwards, rami- 
 fies on its anterior or deep surface. It sends an articular 
 branch to the tibio-fibular articulation. 
 
 The cutaneous branch is known by several names, as the 
 tibial, short, or external saphenous, the posterior cutaneous nerve 
 of the leg, and the communicans tibialis, Fig. 235 (e, e). It 
 usually arises opposite the articulation, and passing down- 
 wards first between the heads of the gastrocnemius, and then 
 on its posterior surface in a small fibrous canal, perforates 
 the deep fascia near the junction of the upper with the 
 middle third of the leg ; sometimes it continues lower down 
 before it becomes subcutaneous. It is joined by the com- 
 municans peronei nerve, a branch of the external popli- 
 teal. The point of union varies greatly, occurring sometimes 
 in the upper part of the leg, and then again not until it has 
 nearly reached the foot. This nerve will be referred to 
 again in the dissection of the back of the leg and the dorsum 
 of the foot, on the outer part of which it terminates. 
 
 The articular branches are three in number, and correspond 
 to the internal and middle articular branches of the popliteal 
 artery, except there is but one superior internal articular nerve, 
 whereas there are two of these arteries; and sometimes this 
 branch, always small, is absent. When present, it .passes in 
 front of the popliteal vessels to reach the artery, which it 
 accompanies in its distribution to the joint. The inferior in- 
 ternal articular branch arises above the joint, and, passing 
 downwards, at first on the outer side of the vessels, then in 
 front of them, joins the corresponding articular artery, which 
 it accompanies in the rest of its course. It is larger than 
 either of the other articular branches for the knee-joint. The 
 middle articular branch arises opposite the articulation, and 
 
548 THE LOWER EXTREMITY. 
 
 proceeds directly to the interior of the joint, perforating the 
 posterior ligament. 
 
 The EXTERNAL POPLITEAL or PERONEAL NERVE, Fig. 
 237, passes downwards along the biceps flexor muscle, in the 
 outer part of the popliteal space, to the point opposite the 
 tibio-peroneal articulation, when it turns outwards, and pene- 
 trates the peroneus longus muscle just below the head of the 
 fibula. While in this muscle, or placed between it and the 
 cervix of the fibula, it divides into its terminal branches, 
 the anterior tibial and the musculo-cutaneous, Fig. 248. These 
 will be described in the dissection of the anterior part 
 of the leg, and the dorsum of the foot. The peroneal nerve 
 is rather more superficial in its course than the internal pop- 
 liteal. It passes over the external condyle of the femur, 
 and the external head of the gastrocnemius. It gives off 
 articular and cutaneous branches ; of the latter, the communi- 
 cans peronei or the peroneal saphenous, is the largest. This 
 usually arises a little above the knee-joint, and passing 
 downwards on the inner side of the peroneal nerve, gets be- 
 tween the gastrocnemius and the deep fascia, which it perfo- 
 rates to unite with the communicans poplitei. Its junction 
 with the communicans poplitei is not constant, and varies 
 very much as to the point at which it takes place. It gives 
 off several small cutaneous branches in its course down the 
 leg. The other cutaneous branch, the peroneal cutaneous, 
 given off by the peroneal nerve, descends behind the exter- 
 nal condyle, and passing down on the outside of the leg, 
 gives off branches which ascend and descend to supply the 
 integument on that part of the leg. The articular branches 
 correspond to the superior and inferior external articular 
 branches of the popliteal artery. The superior external arti- 
 cular branch sometimes arises from the sciatic nerve. It 
 passes downwards in front of the sciatic nerve, when it 
 arises from that nerve, and along the biceps flexor muscle to 
 near the external condyle, then turns outwards above it to be 
 distributed to the joint in company with the corresponding 
 artery. The inferior external articular nerve usually has nearly 
 the same origin as the preceding nerve. It passes down- 
 wards in the outer part of the popliteal space to a point just 
 below the external condyle, and then turns outwards to be 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 549 
 
 238. 
 
 distributed to the joint in company with the inferior external 
 articular artery. 
 
 The POPLITEAL ARTERY, Fig. 238 (i), is a continuation of 
 the femoral. It commences at the lower end of the canal 
 formed by the tendons of the adductores longus and magnus, 
 and passes downwards and outwards, first over the femur, 
 then the posterior ligament of the 
 joint, and lastly the aponeurosis, which 
 covers the popliteal muscle, at the 
 lower border of which, it divides into 
 the posterior tibial and peroneal or 
 fibular. At first, it is to the inner 
 side of the median line of the limb, 
 but gets into it as it descends behind 
 the joint. The popliteal vein, Fig. 
 240 (s), lies behind and a little to the 
 outer side of it above the joint, but 
 directly behind it in the rest of its 
 course. The coats of this vein are 
 very thick, so that when cut it some- 
 times gapes, and might then be mis- 
 taken for the artery. It also adheres 
 very closely to the artery, which 
 should be borne in mind, whenever 
 it is necessary to place a ligature on 
 the latter. The lower part of the 
 artery is partly covered by the heads 
 of the gastrocnemius and the plant- 
 aris; the popliteal nerve also crosses 
 this part of it from the outer to the 
 inner side. It has on the sides of it 
 the different parts which form the 
 boundaries of the popliteal space, 
 which are specified above. The relations of the popliteal 
 artery to the knee-joint are interesting, and should be care- 
 fully observed. When one limb is placed across the other, as 
 in sitting, the pulsations of the artery are distinctly seen in 
 the movements of the foot, so that the beats of the heart can 
 be counted as accurately, by observing the movements of the 
 foot with the legs crossed, as by placing the fingers on the 
 radial artery in the wrist. There are eight branches given 
 
 A VIEW OF THE ARTERIES 
 IN THE POPLITEAL SPACE, 
 RIGHT LEG. 1. Popliteal 
 artery. 2. Internal gastroc- 
 neinial artery. 3. External 
 gastrocneinial artery. 4, 5. 
 Division of these arteries in 
 the substance of the muscle. 
 
550 THE LOWER EXTREMITY. 
 
 off from the popliteal artery, which require to be noticed. 
 Six of these are articular branches, and two are muscular. 
 
 The superior internal articular arteries, consist of two. One 
 of these is sometimes called the great anastomotic artery, Fig. 
 213 (20, 21), of the knee. It may arise from the femoral 
 artery as it is passing through the tendinous sheath to be- 
 come the popliteal ; or it may have its origin still higher up. 
 After perforating the adductor magnus, it divides into several 
 branches. One of these passes downwards behind the sar- 
 torius muscle, in company with the internal saphenous nerve; 
 another one passes downwards through the substance of the 
 vastus internus muscle, and, reaching the inner border of the 
 tendon of the quadriceps extensor muscle, just above the pa- 
 tella, where it becomes subcutaneous, and crossing transversely 
 to the outer side, along the upper border of the patella, it 
 anastomoses with the superior external articular branch. It 
 sends branches to the anterior surface of the patella. One 
 or two branches are distributed principally to the periosteum 
 on the inner and anterior surface of the femur. One of these 
 sometimes takes the place of the next artery to be de- 
 scribed, or terminates by anastomosing with it. 
 
 The lower superior internal articular artery, Fig. 239 (4), 
 arises just above the internal condyle, passes horizontally 
 inwards and around the condyle, to gain its anterior surface. 
 It sends branches to the patella and to the synovial mem- 
 brane, and other branches to the integument, and to anasto- 
 mose with the preceding branch and one or two of the other 
 articular branches. 
 
 The superior external articular artery, Fig. 239 (5), arises just 
 above the external condyle, and, passing under the biceps 
 flexor muscle, divides into several branches; some of which 
 are muscular, and others are periosteal. The former are 
 ascending branches, and go to the biceps and the quadriceps 
 extensor muscles. The latter are found ramifying on the 
 condyle and the anterior surface of the lower part of the 
 femur, and also on the outer part of the patella. They also 
 anastomose freely with the other articular branches. 
 
 The inferior external articular artery, Fig. 239 (s), arises oppo- 
 site the articulation, and passing horizontally outwards in a 
 line corresponding to the joint, and beneath the tendon of 
 the biceps and the external lateral ligaments, divides into an 
 ascending, a transverse, and a descending branch. The first 
 
DISSECTION OF BACK OF THIGH AND THE HAM. 551 
 
 and 
 The 
 
 Fig. 239. 
 
 passes upwards along the outer border of the patella, 
 anastomoses with the superior external articular artery, 
 second, passing transversely below the 
 patella and between the ligamentum 
 patellae and the joint, anastomoses with 
 the inferior internal articular artery ; 
 it also sends small branches to the fat 
 and areolar tissue beneath the liga- 
 mentum patellae. The last one anasto- 
 moses with the anterior recurrent tibial, 
 a branch of the anterior tibial artery. 
 
 The inferior internal articular artery, 
 Fig. 239 (7), arises opposite to the pre- 
 ceding artery, and passing downwards 
 and inwards around the internal tube- 
 rosity of the head of the tibia, and be- 
 neath the tendons of the muscles which 
 form the inner hamstring, and the 
 internal lateral ligament of the knee- 
 joint, it turns upwards towards the 
 patella. It anastomoses with the pre- 
 ceding artery beneath the ligamentum 
 patellae, and also with the superior 
 internal articular arteries. 
 
 The middle articular artery, or the 
 azygos artery, Fig. 2S9 (e), arises from 
 the forepart of the popliteal artery, 
 and passes directly through the pos- 
 terior ligament, to be distributed to the 
 sy no vial membrane, the areolar tissue, 
 and the crucial ligaments within the 
 knee-joint ; some of its branches pene- 
 trate the lower extremity of the femur. 
 
 A VIEW or THE ARTERIES ON THE BACK OF THE EIGHT LEG. THE MUSCLES HAVE 
 
 BEEN REMOVED SO AS TO DISPLAT THE VESSELS IN THEIR WHOLE LENGTH. 1. The 
 
 popliteal artery, cut off so as to show the articular arteries. 2. Lower end of the 
 same artery on the popliteus muscle. 3. Point of bifurcation into the posterior 
 tibial and peroneal. 4. Lower superior internal articular artery. 5. Superior ex- 
 ternal articular artery. 6. Middle articular artery. 7. Inferior internal articular 
 artery. 8. Inferior external articular artery. 9. Branch to the head of the soleus 
 muscle. 10. Origin of the anterior tibial artery. 11. Origin of the posterior tibial 
 artery. 12. Point where it passes behind the internal annular ligament to become 
 the plantar. 13, 14, 15. Muscular branches. 16. Origin of the peroneal artery. 
 17, 17. Muscular branches. 18, 18. Anastomosis of the posterior tibial and pero- 
 neal arteries near the heel. 19. Muscular branch from the anterior tibial. 
 
552 THE LOWER EXTREMITY. 
 
 Instead of one middle artery, there may be several smaller 
 ones going to supply the same parts. Like those which have 
 been described above, it may take its origin from some one of 
 the other articular arteries; all the arteries around the knee- 
 joint vary more or less in their origin, and also in their size. 
 The patella is the centre of their anastomotic connections. 
 
 The gastrocnemial arteries, Fig. 238 (2, 3), arise from the 
 back of the popliteal artery, nearly opposite the articulation, 
 and passing downwards are distributed, one to each of the 
 heads of the gastrocnemius. They are usually larger than the 
 articular branches. They correspond to muscular branches 
 given off from the popliteal artery, above the knee-joint, to 
 be distributed to the muscles in the lower part of the thigh. 
 
 SECT. IY. DISSECTION OF THE POSTERIOR AND THE INNER 
 
 PART OF THE LEG. 
 
 To dissect the posterior part of the leg, the integument 
 may be removed by making an incision from the popliteal 
 space along the median line to the heel, and thence along 
 both the inner and outer borders of the plantar surface of the 
 foot to a point on each side below the malleolus. From this 
 incision the skin can be reflected externally and internally 
 sufficiently to expose all the parts in this region. The foot 
 should be flexed on the leg so as to make the fascia, as well 
 as the muscles to be dissected, tense. Although it is conve- 
 nient to describe, at this time, the parts which correspond to 
 the subcutaneous surface of the tibia, it is not necessary that 
 the integument which covers this surface should be removed 
 in connection with that on the back of the leg. It is better 
 that the student should dissect specially for the internal sa- 
 phenous vein and nerve, as there is nothing else of any im- 
 portance on the inner part of the leg. The vein, if injected, 
 or filled with blood, is easily found and traced; but it is 
 much more difficult to find the nerve, unless it was preserved 
 when the dissection of the anterior part of the thigh was 
 made. To dissect them on the leg, it is immaterial whether 
 the subject be placed on the back or on the face; if on the 
 back, the integument can be reflected from behind forwards, 
 and the dissection can be made in connection with the back 
 of the leg. 
 
POSTEKIOR AND INNER PART OF THE LEG. 553 
 
 Having reflected the integument from the incision made 
 in the median line to a line corresponding to the fibula and 
 external malleolus on the outer side, and to the inner angle 
 of the tibia and internal malleolus on the inner side, the cuta- 
 neous vessels and nerves should be examined. If it be de- 
 cided to dissect the internal saphenous nerve and vein in 
 connection with the back of the leg, then the internal flap 
 must be raised as far as the anterior angle or spine of the 
 tibia. Special care is requisite in raising the integument 
 that the superficial fascia be left in order that the cutaneous 
 vessels and nerves may not be injured or destroyed before 
 they have been dissected. 
 
 There are no arteries in the superficial fascia that require 
 particular notice. 
 
 The veins to be examined in the superficial fascia are the 
 two saphenous, external and internal. The latter was dis- 
 sected in the upper part of its course in connection with the 
 thigh, and the former, with the popliteal space. They both 
 commence on the dorsum of the foot, and are subcutaneous 
 to within a very short distance of their termination, the one 
 in the femoral, and the other in the popliteal vein. They 
 communicate freely with each other on the leg, and sometimes 
 the external joins the internal instead of the popliteal. They 
 contain very few valves, which may contribute to the forma- 
 tion of varix, and also tend to prevent the obliteration of 
 the veins, as they can, in the absence of valves, more readily 
 empty themselves by means of collateral branches ; the in- 
 ternal has from two or three to six valves, and the external 
 only two. 
 
 The INTERNAL SAPHENOUS VEIN, Fig. 208, arises by the 
 internal dorsal vein of the foot, passes backwards and upwards 
 on the inner part of the dorsum, and in front of the ankle- 
 joint to the anterior part of the internal malleolus, and thence 
 along the inner angle of the tibia to the internal and poste- 
 rior part of the knee-joint. In this part of its course it re- 
 ceives branches from both sides of it. In the foot it commu- 
 nicates with the deep plantar vein, and receives the superficial 
 veins of the inner part of the plantar portion of the foot, 
 including the internal calcaneal veins. Sometimes the last- 
 named veins form a trunk which passes upwards behind the 
 internal malleolus. and there unites with the saphenous. 
 47 
 
554 THE LOWER EXTREMITY. 
 
 From the knee to the saphenous opening in the fascia lata, 
 the internal saphenous was described in connection with the 
 anterior part of the thigh. Below the knee it is accompanied 
 by one of the terminal divisions of the internal saphenous 
 nerve. This is the longest vein in the body. 
 
 The EXTERNAL or POSTERIOR SAPHENOUS VEIN, Fig.240(7), 
 commences by the external dorsal vein of the foot, which 
 communicates by quite a large branch with the internal dor- 
 sal vein; thus a sort of an arch is formed, from the extremi- 
 ties of which the saphenous veins take their origin. It passes 
 backwards and upwards around the lower and posterior sur- 
 face of the external malleolus to the outer border of the tendo- 
 Achillis; it then ascends on the back of the leg over the 
 gastrocnemius muscle to the popliteal region. It receives on 
 the dorsum of the foot, at the outer part of the ankle-joint, 
 the small veins which correspond to those received by the 
 internal saphenous. It is accompanied by the external 
 saphenous nerve which the vein crosses twice in its course, 
 passing between it and the skin. 
 
 There are several cutaneous nerves distributed to the in- 
 tegument on the back and inner part of the leg. They have 
 been noticed incidentally in connection with the dissection 
 of the thigh and the popliteal region. 
 
 The COMMUNICANS TIBIALIS, a branch of the internal 
 popliteal, and the COMMUNICANS PERONEI, a branch of the 
 external popliteal, Fig. 285, were observed in the dissection 
 of the popliteal space. They are very regular in their origin 
 and in the upper part of their course, but not so in the latter 
 part of their course. Sometimes the peroneal communicans 
 merely sends a branch to join the tibial communicans, and 
 then again it terminates in it. They vary as to the point 
 where they perforate the deep fascia, sometimes not doing it 
 until they reach the lower part of the leg ; the distribution, 
 however, is the same. The tibial communicans, after it has 
 received the anastomosing branch from the peroneal commu- 
 nicans, or has been joined by the nerve itself, is by some 
 called the external saphenous. Fig. 235 (e, e). It descends on 
 the outer side of the tendo-Achillis in company with the ex- 
 ternal saphenous vein, to a point behind the external malleo- 
 lus, where it sends off external calcaneal branches to the inte- 
 gument on the heel ; it then continues forwards below the 
 
POSTERIOR AND INNER PART OF THE LEG. 555 
 
 malleolus to the outer part of the dorsum of the foot, and 
 divides into two branches, one to supply the external part of 
 the little toe, and the other, the contiguous surfaces of the 
 same toe and the fourth toe; the last-named division receives 
 an anastomosing branch from the musculo-cutaneous nerve. 
 When the peroneal communicans continues down the leg, it 
 usually terminates in supplying branches to the outer part 
 of the" heel ; it gives oft' branches to the integument as it 
 passes down the leg. It also frequently sends off a malleolar 
 branch which, passing over the external malleolus, either 
 anastomoses with, or takes the place of, a branch from the 
 musculo-cutaueous. 
 
 The INTERNAL SAPHENOUS NERVE, Fig. 212 (e), Fig. 
 (2, 2), gives off a branch named the patellar on the inner side 
 of the knee, which perforates the sartorius muscle, and passing 
 downwards a short distance above the tendon of the sartorius, 
 turns outwards arid divides into ascending, middle, and descend- 
 ing branches, which ramify on the anterior surface of the pa- 
 tella, the ligamentum patellae, and the forepart of the tibia. 
 After giving off the patellar branch, the saphenous passes 
 over the tendon of the gracilis to join the internal saphenous 
 vein, which it accompanies to the foot. Its connection with 
 the vein is such as to render the dissection of either of them 
 somewhat difficult, as it twines around the vein, splits and 
 runs a short distance on each side of it, and then unites 
 again. In its course down the leg it sends branches, both 
 externally and internally, to the integument. The internal 
 filaments are short, and anastomose in the upper and poste- 
 rior part of the leg with filaments derived from a cutaneous 
 branch given off from the internal saphenous just before it 
 enters the tendinous canal formed by the adductor magnus, 
 or from a cutaneous branch given off by the obturator nerve, 
 which then takes the place of the one from the internal 
 saphenous ; in the lower part they anastomose with filaments 
 from the external saphenous nerve. The external filaments 
 are long, and descend obliquely outwards in front of the 
 tibia. About three or four inches above the ankle, the in- 
 ternal saphenous divides into a posterior and an anterior 
 branch; the former passes directly downwards in front of 
 the internal malleolus to the inner part of the foot, extend- 
 ing as far as the sole, and giving filaments in its course to 
 
556 THE LOWER EXTREMITY. 
 
 the integument on each side of it; the anterior branch 
 continues to accompany the saphenous vein to the dorsum 
 of the foot, giving branches to the ankle-joint and to the 
 skin on the foot. 
 
 The posterior femoral cutaneous branch of the small sciatic, 
 Fig. 234 (a), terminates in filaments sent to the integument 
 on the back of the leg, and also to anastomose with the 
 external saphenous nerve. 
 
 The peroneal cutaneous branch, Fig. 234 (5, 7), of the exter- 
 nal popliteal nerve is distributed to the integument on the 
 outer part of the leg. Having completed the dissection of 
 the vessels and nerves, the superficial fascia should now be 
 removed to expose the deep fascia. 
 
 The deep fascia on the back of the leg is continuous with 
 the deep fascia in the popliteal space, where it is strength- 
 ened by fibrous expansions from the tendons of the biceps, 
 the semi-tendinous, the gracilis, and the sartorius. It is at- 
 tached laterally, to the fibula on the outer side, and to the 
 inner angle of the tibia on the inner side ; below, it is con- 
 nected to the internal annular ligament of the ankle. There 
 is another fascia on the back of the leg, which separates the 
 superficial from the deep-seated layer of muscles. This will 
 be noticed when it is reached in the course of the dissection. 
 
 The internal annular ligament, Fig. 241 (14), arises from 
 the margin of the internal malleolus, and is inserted into 
 the internal side of the os calcis and the plantar aponeurosis. 
 It spreads out so that it is much broader below than above. 
 From its deep surface septa proceed inwards, to form several 
 fibrous canals or sheaths for the tendons of the deep muscles 
 of the back of the leg, and also for the posterior tibial nerve 
 and vessels. The use of the fascia just described is to pro- 
 tect the parts beneath it, and to form for the muscles sheaths, 
 which increase their power of contraction ; the annular liga- 
 ment keeps the tendons which pass beneath it in their proper 
 position. 
 
 The three following muscles constitute the superficial 
 layer on the back of the leg. They are large, except the 
 plantaris, and easily dissected. Two of them, as will be ob- 
 served, arise from the femur above the articulation of the 
 knee, and the third one arises from both bones of the leg, 
 while they all are inserted into the os calcis. 
 
POSTERIOR AND INNER PART OF THE LEG. 557 
 
 The GASTROCNEMIUS or GEMELLUS, Fig. 236 (4, 4), arises 
 by two heads, an external and an internal. The internal head, 
 sometimes called the gemellus interims, is longer and larger 
 than the external. It arises, muscular and tendinous, from a 
 depression and a rough surface around it on the outer and 
 upper part of the internal condyle, and from a ridge that is 
 formed by the bifurcation of the linea aspera; the external 
 head or gemellus externus arises from the outer and back part 
 of the external condyle, and from a ridge above it. The 
 tendon of each head is quite thick and stout at its origin, 
 but spreads out as it descends behind the articulation of the 
 knee and on the side of the popliteal space, to join the one 
 on the opposite side. The fibres which go to form the prin- 
 cipal part of the belly of the muscle, have their origin on 
 the anterior surfaces of these tendinous expansions. Most of 
 the fibres which arise directly from the bone, end in a ten- 
 dinous substance which is placed in the median line of the 
 muscle, while those which arise from the tendon pass down- 
 wards to be inserted into the posterior surface of a broad 
 aponeurotic tendon, which gradually becomes narrower until 
 it ends in the tendo-Achillis. The part of the belly formed 
 \)j the inner head, is much thicker than that formed by the 
 outer head. A synovial sac is frequently found between each 
 head, most commonly the left one only, and the correspond- 
 ing condyle ; in some instances they communicate with the 
 knee-joint. Sometimes a sesamoid bone, or fibro-cartilage, is 
 met with in one or both of the heads behind the condyle. 
 The posterior surface of the gastrocnemius is convex, while 
 the anterior is flattened. It forms a considerable portion of 
 the calf of the leg. The tendo Achillis will be noticed in 
 connection with the soleus. 
 
 The next muscle to be dissected is the plantaris. This is 
 so small, and so closely connected to the gastrocnemius, that 
 the student is very liable to overlook it unless his attention 
 has been directed to it. 
 
 The PLANTARIS consists of a small muscular belly termi- 
 nating in a long slender tendon, the longest in the body. It 
 arises from a rough surface above the external condyle, and 
 from ligamentous fibres placed behind it, and passes down- 
 wards on the inner side of the external head of the gastro- 
 cnemius, which partly covers it, and of which it frequently 
 
 47* 
 
558 THE LOWER EXTREMITY. 
 
 seems to be a part, to end about three inches below its origin, 
 in a small tendon which disappears beneath the gastrocne- 
 mius, to appear again on the inner side of the tendo-Achillis, 
 which it accompanies to the os calcis, into which it is inserted, 
 either on the inner side of, or anterior to that tendon. The 
 upper part of the tendon is placed between the gastroene- 
 mius and soleus, having, with the muscular part, a direction 
 somewhat oblique from above downwards, and from with- 
 out inwards. This muscle is sometimes wanting, or its ten- 
 don may terminate in condensed areolar tissue before it 
 reaches the heel. 
 
 The SOLEUS, Fig. 236 (5, 5), is placed beneath the gastroc- 
 nemius, which must be partly or wholly raised to expose it. 
 This may be done by detaching both heads at their origin ; 
 or by cutting across the muscle just below the junction of 
 its two heads ; or by simply detaching the internal head, 
 separating the muscle from the parts beneath it, and then 
 turning it outwards. It is immaterial which plan is adopted, 
 provided the different muscles are preserved so that they can 
 be replaced after the dissection has been completed, for the 
 purpose of studying their relations to each other, and more 
 particularly to the vessels and nerves in this region. The 
 soleus has three origins. The^rs^ is by a strong tendon from 
 the posterior part of the head of the fibula, and from the 
 outer border and the posterior surface of the upper two 
 thirds of its body; the second is from an oblique line, called 
 the linea poplitei, on the posterior surface of the upper part 
 of the tibia, and from the middle third of the inner angle 
 of the same bone ; the third one is from a tendinous arch 
 extending from the head of the fibula to the commence- 
 ment of the linea poplitei. It is beneath this arch that the 
 vessels and nerves pass from the popliteal space to the back 
 of the leg, to get between the superficial and deep-seated 
 layers of muscles, and by which they are protected from 
 pressure by the action of the muscles between which they 
 are placed. The fibres arising in the manner above men- 
 tioned pass downwards, some of them more or less obliquely, 
 to be inserted into the anterior surface of a tendinous expan- 
 sion, which spreads out to form a considerable portion of the 
 posterior surface of the muscle. This tendon, like the lower 
 one of the gastrocnemius, diminishes in breadth, but in- 
 
POSTEKIOB AND INNER PART OF THE LEG. 559 
 
 creases in thickness as it passes downwards to end in the 
 tendo-Achillis. The muscular belly of the soleus is pro- 
 longed some distance further down than that of the gastroc- 
 nemius. The opposing surfaces of these muscles are per- 
 fectly fitted to each other, and are separated only by loose, 
 delicate areolar tissue, which allows the one to glide on the 
 other with the greatest facility. Taken together, they form 
 the calf of the leg ; the upper part being formed mostly by 
 the gastrocnemius, the lower part by the soleus. Perhaps 
 no two muscles in the body present a more beautiful appear- 
 ance than these two, when fully developed and properly dis- 
 sected. This is owing not only to their perfect symmetry of 
 form, but to the manner in which the muscular and tendinous 
 structures are distributed in them. 
 
 The TENDO-ACHILLIS, Fig. 236 (e), is the tendon of inser- 
 tion common to the gastrocnemius and soleus. It is from 
 three to four inches in length, being the largest and strongest 
 tendon in the body. It is inserted into the lower part of the 
 posterior extremity of the os calcis, being separated from all 
 the upper and posterior surface of the bone by a synovial 
 sac. It is separated from the posterior tibial vessels and 
 nerve, which are placed beneath it, by areolar tissue and 
 a dense fibrous membrane. The distance between it and 
 the vessels allows of its being divided without any risk to 
 them. 
 
 The action of the gastrocnemius and soleus will be the 
 same, as far as the ankle-joint is concerned, as both of them 
 pass over it ; the former, as it passes over the knee-joint, can 
 act on the leg as well as the foot, or on the thigh when the 
 foot is made the fixed point. The office which they are re- 
 quired to perform demands that they should be powerful 
 muscles. Making their origin the fixed point, they are ca- 
 pable of raising the entire body, as is done at every step that 
 is taken in walking. When their attachments, and the re- 
 lations which they sustain to the joints that they pass over, 
 are understood, there will be no difficulty in understanding 
 their actions. The action of the plantaris is so little that it 
 can produce no marked effect, and as it is frequently absent, 
 or when present, void of any fixed attachment below, must 
 be unimportant. 
 
 The three muscles just noticed may now be removed for 
 the purpose of examining the fascia, which separates them 
 
560 THE LOWER EXTREMITY. 
 
 from the posterior tibial vessels and nerve and the deep 
 layer of muscles. It is an extension of the one that covers the 
 popliteus muscle, downwards to the foot, where it is blended 
 with the internal and external annular ligaments. Laterally, it 
 is attached externally to the fibula, and internally to the inner 
 border or angle of the tibia. It binds down the muscles 
 which are placed under it; and should be observed with re- 
 ference to the formation of pus beneath it, and the direction 
 it would be most likely to take. It shows the depth of the 
 posterior tibial artery, and hence may be made an important 
 guide for finding that vessel. When this fascia is removed, 
 the following parts will be exposed: 
 
 The popliteal artery will be seen at the lower border of 
 the popliteus muscle, dividing into the anterior and posterior 
 tibial arteries. The former is appropriated to the anterior 
 part of the leg and the dorsum of the foot; the latter is dis- 
 tributed mainly to the back of the leg and the plantar por- 
 tion of the foot. 
 
 The POSTERIOR TIBIAL ARTERY, Fig. 239 (n, 12), com- 
 mences at the bifurcation of the popliteal at the lower border 
 of the popliteus muscle, and extends down the leg to the 
 groove formed by the internal malleolus and the os calcis, 
 where, beneath the internal annular ligament, or the origin of 
 the abductor pollicis, it divides into the external and internal 
 plantar arteries. At first it is inclined inwards for a short 
 distance, after which it has a vertical direction to its termi- 
 nation. In the upper part of its course it rests on the tibialis 
 posticus, in the middle on the flexor longus digitorum com- 
 munis, and in the lower part it is in apposition with the tibia 
 and the ankle-joint. In the upper two-thirds of its course it 
 is covered by the gastrocnemius and soleus muscles; in the 
 lower third it lies along the inner side of the tendo-Achillis and 
 the os calcis, and is covered only by the integument and the 
 different fasciae of this region, including the internal annular 
 ligament. It is placed midway between the internal malleo- 
 lus and the os calcis, being separated from the former by the 
 tendons of the flexor longus digitorum communis and the 
 tibialis posticus, and from the latter by the tendon of the 
 flexor longus pollicis. The posterior tibial nerve is at first on 
 the outer side, then behind, and in the lower part of the leg 
 on the inner side of it, where it is separated from the artery 
 by one of the venas comites. 
 
POSTERIOR AND INNER PART OP THE LEG. 561 
 
 Fig. 240. 
 
 The depth and central position of the upper half or two 
 thirds of the posterior tibial artery, and the same is true of 
 the peroneal artery, as will be seen, renders it one of the most 
 difficult arteries in the body to be reached in the living sub- 
 ject for the purpose of applying a liga- 
 ture to it. 
 
 The posterior tibial artery gives off 
 several branches in its course down the 
 leg. The first one to be noticed is the 
 internal recurrent branch. This passes 
 round the inner border of the tibia, then 
 upwards to the internal tuberosity of 
 that bone, where it anastomoses with the 
 inferior internal articular branch of the 
 popliteal artery. The next branch to 
 be observed is the nutritious artery of 
 the tibia. This enters the nutritious 
 foramen, and is distributed to the inter- 
 nal lamellae of the bone, including the 
 medullary membrane. It is remark- 
 able for its large size as compared with 
 other arteries of this class. Sometimes 
 it is a branch of the anterior tibial 
 artery. Before entering the bone, the 
 nutritious artery usually gives off one 
 or more muscular branches. The next 
 branch to be examined is one of the 
 principal arteries of the leg. 
 
 The PERONEAL ARTERY, Fig. 239 
 (ie, is), arises from the posterior tibial 
 usually about an inch below the bifur- 
 cation of the popliteal artery, and passes 
 
 THE ARTERIES AND DEEP-SEATED VEINS ON THE BACK OF THE RIGHT LEG. 1. 
 Popliteal vein. 2. Popliteal artery. 3, 4. Vein and artery in their relative position 
 on the back of the knee-joint. 5. Popliteal vein on the inner side of the joint. 6. 
 Popliteal artery to the outer side and beneath it. 7. Posterior or short- saphenous 
 vein. 8, 9. Internal articular vessels, both arteries and veins. 10, 11. External 
 articular vessels, both arteries and veins. 12. Junction of the peroneal and poste- 
 rior tibial veins. 13. A venous branch from the anterior tibial vein. 14. A vein 
 from the gastrocnemius. 15. Anterior tibial artery going through the interosseous 
 ligament. 16, 16. Posterior tibial artery. 17, 17. Its two venae comites. 18, 18. 
 Peroneal artery. 19, 19. Its two vense comites. 20. Vessels on the heel. 
 
562 THE LOWER EXTREMITY. 
 
 at first obliquely downwards and outwards, to penetrate the 
 flexor longus pollicis muscle, in which, or between it and 
 the fibula, it extends vertically to within a short distance of 
 the ankle-joint, where it divides into the posterior and ante- 
 rior peroneal branches. Between its origin and the flexor 
 longus pollicis, it is placed between the soleus behind and 
 the tibialis posticus in front, and gives off in this part of 
 its course branches to those muscles ; a little lower down 
 it supplies a nutritious branch to the fibula; and still lower, 
 it sends quite a large branch to join the posterior tibial 
 artery; this anastomosing branch passes transversely, or 
 nearly so, across the interosseous ligament; sometimes it 
 is met with very large; when this occurs, the posterior 
 tibial is usually quite small above its junction with this 
 branch of the peroneal artery. Besides those named, the 
 peroneal artery sends branches to the peronei muscles, and 
 to the periosteum on the fibula. The anterior peroneal 
 branch perforates the interosseous ligament, and thus gets 
 into the lower part of the anterior interosseous fossa, where 
 it anastomoses with the external malleolar branch of the 
 anterior tibial artery. This is an interesting anastomosis, on 
 account of the large size which this branch of the peroneal 
 artery sometimes presents. It occasionally takes the place 
 of the anterior tibial artery in supplying the arteria dorsalis 
 pedis. It sends small branches to the peroneus tertius 
 muscle and to the ankle-joint, including the articulation be- 
 tween the tibia and fibula. The posterior peroneal branch 
 passes down behind the external malleolus, and over the 
 ankle-joint, to reach the outer posterior part of the os calcis, 
 on the surface of which it ramifies, anastomosing with 
 branches of the posterior tibial, external plantar, and the 
 anterior peroneal, or external malleolar branch. The integu- 
 ment and adipose substance on the bottom of the heel are 
 supplied principally from this branch. 
 
 The DEEP-SEATED VEINS, Fig. 240, on the back of the 
 leg, consist of venae comites, which accompany the arteries. 
 Those which accompany the peroneal artery are usually 
 larger than those accompanying the posterior tibial. The 
 artery is generally placed between its venaa comites, between 
 which frequent communications take place across the artery. 
 
POSTERIOR AND INNER PART OF THE LEG. 563 
 
 The deep-seated veins on the back of the leg unite to form 
 the popliteal vein. 
 
 The POSTERIOR TIBIAL NERVE, Fig. 237, is a continua- 
 tion of the internal popliteal, and commences at the lower 
 border of the popliteus muscle, where it is placed on the 
 inner side of the posterior tibial artery; as it descends in 
 company with the artery it crosses over to the outer side of 
 it, and continues in this position to the space between the 
 internal malleolus and the os calcis, where it divides into the 
 external and internal plantar nerves. In its course on the 
 leg it gives off branches to the deep layer of muscles and to 
 the integument on the heel. The nerve for the flexor longus 
 pollicis accompanies the peroneal artery to a short distance 
 above the ankle-joint. It usually arises by a common trunk 
 with the branch for the flexor longus digitorum communis. 
 The branch for the tibialis posticus arises a little distance 
 below the knee-joint, and a little higher than the origin of 
 the branches for the other muscles; it penetrates the muscle 
 near its middle, having sent filaments to it in its course to 
 this point. The internal calcaneal branches arise by a sin- 
 gle trunk behind the ankle-joint, winds around the os calcis, 
 on its inner side, to reach the integument and adipose sub- 
 stance on its lower surface, where it divides into a branch 
 which goes to the posterior part of the heel, and one that 
 goes to the anterior part. The relations of the posterior 
 tibial nerve to the muscles are the same as those of the artery 
 which it accompanies. The deep layer of muscles which are 
 next to be dissected consist of four. The first one, or popli- 
 teus, is covered by an aponeurosis or fascia, by the removal 
 of which the muscle will be exposed. To separate the three 
 muscles below this from each other, it is sometimes better to 
 find their tendons first, and then trace each one upwards. It 
 is not unfrequently with difficulty that any line of separation 
 can be found between the upper and middle portions of these 
 muscles, unless it is followed up from their tendons below ; 
 this is more especially the case with the tibialis posticus and 
 the flexor longus digitorum communis. 
 
 The POPLITEUS, Fig. 241 (G), is a flat, triangular-shaped 
 muscle, placed behind and below the knee-joint. It arises by 
 a round thick tendon from a depression on the outer surface 
 of the external condyle of the femur, just below the origin 
 
564 THE LOWER EXTREMITY. 
 
 of the external head of the gastrocnemius, and the upper 
 attachment of the external lateral ligament ; it passes down- 
 wards and backwards beneath the external lateral ligament, 
 and behind the outer part of the articulation, to the upper 
 part of the tibia, into the posterior surface of which it is 
 inserted, above an oblique ridge named the linea poplitei. Its 
 tendon is connected to the external semilunar cartilage by 
 ligamentous fibres, and also to the synovial membrane, by 
 which it is partly surrounded, and through which connection 
 a communication is sometimes found to exist between the 
 articulation of the fibula with the tibia, and the knee-joint. 
 The action of the popliteus is to assist the hamstring muscles 
 in flexing the leg on the thigh ; or it may flex the thigh on 
 the leg ; it may also rotate the tibia slightly, or the femur 
 when the tibia is fixed. By its connection with the semi- 
 lunar cartilage, it may fix it in its proper place. 
 
 The FLEXOR LONGUS DIGITORUM COMMUNIS PEDIS, Fig. 
 241 (7), arises from the posterior surface of the tibia, com- 
 mencing just below the insertion of the popliteus and the 
 origin of the soleus, and extending down to within three or 
 four inches of the ankle ; it also has some fibres arising from 
 the aponeurosis on the tibialis posticus, and from intermus- 
 cular septa. From this origin the fibres pass obliquely back- 
 wards and inwards, to end in a tendon which descends to a 
 groove behind the internal malleolus, where it is covered and 
 fixed in its place by the internal annular ligament, and sepa- 
 rated from the tendon of the tibialis posticus by a process of 
 the annular ligament. It is surrounded by a synovial mem- 
 brane which extends some distance above and below the 
 groove. From this point it is directed forwards and a little 
 outwards, to pass through a groove in the astragalus, and also 
 one in the os calcis, when it enters the sole of the foot, where 
 it is first joined by a slip from the tendon of the flexor longus 
 pollicis, and next by the musculus accessorius ; it now divides 
 into four tendons, one for each of the four smaller toes. Each 
 tendon passes through a fibrous sheath lined by synovial 
 membrane. This sheath corresponds to the under surface of 
 the first and second row of phalanges. Each contains also 
 one of the tendons of the flexor brevis digitorum communis, 
 each of which is slit opposite the base of the second phalan- 
 geal bone, for the transmission of the corresponding tendon 
 
POSTERIOR AND INNER PART OF THE LEG. 565 
 
 of the long flexor, as it passes forwards, to be inserted into the 
 base of the last phalangeal bone. 
 
 The FLEXOR LONGUS POLLICIS PEDIS, Fig. 241 (9), is placed 
 to the outer side of the preceding muscle, from which it is partly 
 separated by the tibialis posticus. It arises from the lower 
 two-thirds of the fibula, from the aponeurosis which covers the 
 tibialis posticus, and from the interosseous 
 membrane near the lower end of the fibula, Fig. 241. 
 
 and also from a fibrous septum between it 
 and the peronei muscles. The fibres pass 
 obliquely downwards and inwards, to end 
 in a tendon which descends to a groove first 
 on the inner side of the astragalus, and 
 then of the os calcis, being kept by a strong 
 fibrous sheath, firmly applied to these bones; 
 from this point it is continued into the sole 
 of the foot, and through it to the base of 
 the last phalangeal bone of the great toe, 
 into which it is inserted. Its tendon crosses 
 above that of the long common flexor of 
 the toes, and gives to it a tendinous slip ; in 
 the latter part of its course, it is placed be- 
 tween the bellies of the short flexor of the 
 great toe. Opposite the internal malleolus, 
 it is separated from the tendon of the long 
 common flexor of the toes and the tendon of 
 the tibialis posticus, by the posterior tibial 
 vessels and nerve. The peroneal vessels are 
 placed between its origin from the fibula, 
 and its origin from the aponeurosis on the 
 inner side of that bone. Its tendon passes 
 very nearly through the whole muscle. Its 
 action is to flex the great toe, and, having 
 
 THE DEEP LAYER or MUSCLES OF THE POSTERIOR TIBIAL REGION OF THE LEFT 
 LEG. 1. The lower extremity of the femur. 2. The ligamentum posticum Wins- 
 lowii. 3. The tendon of the semi-membranosus muscle dividing into its three slips. 
 4. The internal lateral ligament of the knee-joint. 5. The long external lateral 
 ligament. 6. The popliteus muscle. 7. The flexor longus digitorum. 8. The 
 tibialis posticus. 9. The flexor longus pollicis. 10. The peroneus longus muscle. 
 11. The peroneus brevis. 12. The tendo-Achillis divided near its insertion into 
 the os calcis. 13. The tendons of the tibialis posticus and flexor longus digitorum 
 muscles, just as they are about to pass beneath the internal annular ligament (14) 
 of the ankle; the interval between the latter tendon and the tendon of the flexor 
 longus pollicis is occupied by the posterior tibial vessels and nerve. 
 
 48 
 
566 THE LOWER EXTREMITY. 
 
 done this, to extend the foot on the leg, and to adduct the 
 foot. 
 
 The TIBIALIS POSTICUS, Fig. 241 (s), is situated ia the 
 middle of the interosseous fossa, or rather occupies a large 
 portion of it, except at the lower part, where it has become 
 tendinous. It arises from both bones of the leg, and from 
 the interosseous membrane ; from the fibula, it arises between 
 the origin of the soleus muscle and the outer malleolus, 
 from the tibia, below the linea poplitei, and from nearly 
 the whole of the posterior surface of the interosseous mem- 
 brane; it also arises from the intermuscular septa, which 
 separate it from the two preceding muscles. The fibres, which 
 arise from these different points, pass downwards to end in a 
 tendon which extends nearly the whole length of the muscle, 
 occupying the central part of it. This tendon passes between 
 that of the flexor longus digitorum communis and the tibia, 
 to get into a fibrous canal above and behind the internal 
 malleolus, and to the inner side of the tendon of the last- 
 named muscle ; it then continues obliquely forwards and is 
 inserted into the scaphoid and the internal and middle cunei- 
 form bones ; sometimes some fibres can be traced from it to 
 the base of the metatarsal bone of the great toe, and also to 
 the external cuneiform bone. A sesamoid bone, or fibro- 
 cartilage, is very frequently found in its tendon just behind 
 its insertion into the scaphoid bone. A synovial membrane 
 is placed between this sesamoid body and the scaphoid bone. 
 The upper end of the muscle is notched for the passage of 
 the anterior tibial vessels. Its action is to extend the foot 
 on the leg; it will also invert the plantar surface of the foot 
 by elevating its inner border; with the long flexor muscles of 
 the toes it may act as a substitute for the gastrocnemius and 
 soleus in case the tendo-Achillis has been injured. It also 
 assists in steadying the foot in standing or walking. 
 
 Having completed the dissection of the back of the leg, the 
 student should review what he has been over, including in 
 this review the popliteal space. He should carefully examine 
 the deepfascice to see in what manner they would limit or favor 
 in any particular direction, the extension of collections of 
 pus. He will notice that pus, collected beneath the deep fascia 
 of the popliteal space, might extend to the foot without en- 
 countering any obstruction from fascia ; and also that in en- 
 
POSTERIOR AND INNER PART OF THE LEG. 567 
 
 tering tlie leg it would pass down in the sheath of the super- 
 ficial layer of muscles ; or, if it should form beneath the fascia 
 which covers the deep layer of muscles, it might pass under 
 the internal annular ligament and enter the sole of the foot. 
 Thus it will be seen that the cavity formed by the sheath of 
 the superficial layer of muscles communicates with that form- 
 ed by the fascia lata of the thigh, while that formed by the 
 sheath of the deep layer communicates with that formed by 
 the plantar aponeurosis. 
 
 He should examine the different arteries of this region, 
 and study their relations to prominent points which can 
 always be seen or felt in the living subject, and by which he 
 will be enabled at any time to locate any one of these ves- 
 sels ; and also, such points as will serve for guides in finding 
 either one of the arteries in case he should ever have occasion 
 to ligate them in his practice. Take, for example, the pos- 
 terior tibial artery two or three inches below its origin ; he 
 should carefully examine its relations to the gastrocnemius 
 and soleus muscles, in order to determine whether it could 
 be reached better by cutting directly upon it through those 
 muscles, or by detaching the soleus from the tibia or fibula, 
 and then following the fascia which separates the superficial 
 from the deep layer of muscles. He has already seen in the 
 dissection of these parts that this fascia covered the artery ; 
 he has also seen the position of the nerve, so that he would 
 be able to take this into consideration in deciding the best 
 way to reach the artery without injuring the nerve. He 
 should likewise study the relations of the same artery lower 
 down ; and, also, the peroneal artery. The position of the 
 tendons of the long muscles of the foot as they pass through 
 the sulcus formed, on the inner side by the internal malleolus, 
 and on the outer side by the tendo-Achillis and the os calcis, 
 should receive special attention. It may happen to him 
 some time that he will have occasion to divide one or more 
 of these tendons. A short time devoted to the study of these 
 parts, now fhey are before him, may prove to be of immense 
 use to him at some future time, and he cannot neglect this 
 opportunity to acquire this knowledge without doing himself 
 great injustice, as well as those who will have a right to de- 
 mand of him the application of it to themselves. 
 
568 THE LOWER EXTREMITY. 
 
 SECT. V. DISSECTION OF THE ANTERIOR AND OUTER PARTS 
 
 OF THE LEG, AND THE DORSUM OF THE FOOT. 
 
 As there is so little on the dorsum of the foot that is not 
 found on the leg, while almost every thing to be dissected on 
 the leg, such as fascia, muscles, vessels, and nerves, not only 
 extend to, but pass over the dorsum of the foot, we think it 
 is better to make but one dissection of these regions. Nor is 
 the number of the parts to be examined so great that the 
 student cannot, if proper means be employed to preserve the 
 subject from drying or decomposing, dissect them in a satis- 
 factory manner while they are in a suitable condition for 
 this purpose. There is, perhaps, more danger to be appre- 
 hended from the parts drying and becoming hard on the foot, 
 than of their decomposing, especially if a strong solution of 
 chloride of zinc has been used as an antiseptic ; this can be 
 prevented only by the constant use of wet-cloths kept ap- 
 plied to the limb during the intervals of dissecting. The foot 
 should be extended on the leg, and kept in this position by 
 means of hooks ; in dissecting the muscles it will be neces- 
 sary, not only to extend the foot, but to abduct it in dissect- 
 ing the tibialis anticus, and adduct it in exposing the pe- 
 ronei muscles. 
 
 To remove the integument a vertical incision may be 
 made, commencing at the knee and extending it down the 
 leg a little to the outside of the spine of the tibia to the ankle- 
 joint, and thence in a straight line on the dorsum of the foot 
 to the space between the great and the second toe. Two 
 transverse incisions should be made ; an upper one extending 
 from the ligamentum patellae to the outer hamstring, and a 
 lower one from one malleolus to the other in front of the 
 ankle-joint. If the thigh and back part of the leg have 
 already been dissected, it may not be necessary to make any 
 new incisions, or it may be more convenient to make them 
 in a different manner; the student will have no Difficulty in 
 determining the most convenient way, when he remembers 
 that the manner in which the skin is removed has nothing to 
 do with the dissection of the parts beneath it, except to get 
 it out of the way as fast as, but no faster than is required to 
 expose those parts, and to use it for covering them when he is 
 not dissecting. Care is necessary here as well as elsewhere in 
 
ANTERIOB PAKT OF LEG, DOESUM OF THE FOOT. 569 
 
 Fig. 242. 
 
 removing it not to take up the superficial fascia with it, if 
 the subcutaneous vessels and nerves are to be examined. 
 
 Having raised the integument on the leg as far as the in- 
 ner angle of the tibia internally, and to a short distance 
 behind the fibula externally, and on the foot as far as its 
 inner and outer borders back to within about an inch of the 
 heel, the vessels and nerves in the superficial fascia should be 
 dissected. There is neither any subcutaneous artery or vein 
 of sufficient size on the anterior or outer 
 part of the leg, to require any special 
 notice. The only nerve of much im- 
 portance is the musculo-cutaneous, Fig. 
 242 (s), a branch of the external popli- 
 teal or peroneal nerve. This nerve 
 must be looked for perforating the 
 deep fascia near the junction of the 
 middle, with the lower third of the leg, 
 and a little to the inner side of a line 
 corresponding to the fibula. It is quite 
 a large nerve, and with a little care 
 the student cannot fail to find it ; and 
 when found, it is easily traced down the 
 leg, and on the dorsum of the foot. It 
 gives off a small branch called the exter- 
 nal malleolar branch, which passes over 
 the external malleolus, and anastomoses 
 with a branch of the external saphe- 
 nous nerve. It then divides into four 
 terminal branches, which are distributed 
 to the toes. The first one, commencing 
 internally, goes to the inner side of the 
 great toe ; the second goes to the outer 
 side of the great toe, and to the inner 
 side of the second toe ; the third sup- 
 plies the outer part of the second, and 
 the inner part of the third toe; the 
 
 fourth is distributed to the outer side of OF THE LEG, AND THE DOR- 
 the third, and to the inner side of the 
 fourth toe. The last-named branch 
 anastomoses with the external saphe- 
 nous, which not unfrequently supplies 
 
 48* 
 
 PLAN OF THE CUTANEOUS 
 NERVES ON THE FOREPART 
 
 become subcutaneous. 2,2,2. 
 Branches of 'the external 
 popliteal. 3. Musculo-cuta- 
 neous. 4. Anterior tibial. 
 
570 
 
 THE LOWER EXTREMITY. 
 
 this branch, instead of the museulo-cutaneous. The branch 
 that supplies the inner part of the great toe anastomoses 
 with the internal saphenous nerve. The other branches 
 anastomose with the anterior tibial nerve ; sometimes they 
 are wanting, when their places are supplied by branches of 
 the anterior tibial. The branches of the museulo-cutaneous 
 not only supply the toes to which they 
 Fig. 243. are distributed, but also the integument 
 
 on the lower and forepart of the leg, and 
 on the middle part of the dorsum of the 
 foot. The integument on the inner part 
 of the leg is supplied by branches of 
 the internal saphenous. Fig. 242 (i), 
 while the external popliteal, or the pe- 
 roneal cutaneous, Fig. 242 (2, 2, 2), sup- 
 ply the integument on the outer part 
 of the leg. 
 
 After removing the skin from the 
 dorsurn of the foot, besides the nerves 
 just noticed the superficial veins, Fig. 
 243, should be examined. These consist 
 of an internal and an external dorsal vein, 
 which are connected across the meta- 
 tarsus so as to form an arch called the 
 dorsal arch. The veins of the toes empty 
 into this arch ; and, also, branches from 
 the internal and external plantar veins. 
 The saphenous veins have their origin 
 in this arch, or rather in the internal 
 and external dorsal veins. There are 
 other veins on the dorsum of the foot 
 and on the anterior part of the leg, but 
 they require no special notice ; they ter- 
 minate either in the internal or external 
 saphenous vein. The superficial fascia 
 
 THE SUPERFICIAL VEINS OF THE FRONT OF THE RIGHT LEG. 1. Internal or long 
 saphenous above the leg. 2. The same vein on the inner side of the leg. 3. A 
 transverse branch below the knee which receives all the venous branches from the 
 front of the leg. 4. A branch which anastomoses with the deep-seated veins. 5. 
 The dorsal vein on the inner side of the foot. 6. The arch formed by the inner and 
 outer dorsal veins. 
 
ANTERIOR PART OF LEG, DORSUM OF THE FOOT. 571 
 
 may now be dissected off to expose the deep fascia, and the 
 external and anterior annular ligaments. 
 
 The deep fascia on the anterior part of the leg is thicker 
 and stronger than on any other part. It is composed in the 
 tipper part of fibres which have an oblique direction, and 
 interlace with each other; in the lower part they are circular. 
 It is continuous above with the fascia lata as it is continued 
 downwards in front of the knee-joint, and is also attached to 
 the tubercle of the tibia; internally, it is attached to the spine 
 of the tibia ; externally, to the fibula ; and below, to the ante- 
 rior annular ligament. Thus, it will be seen that it forms a 
 sheath for the muscles on the anterior part of the leg ; besides 
 forming a sheath common to the muscles, it sends processes or 
 intermuscular septa in between them, especially in the upper 
 part of the leg. The tibialis anticus and the extensor longus 
 digitorum communis have, as will be seen, their origin in 
 part from these intermuscular septa ; they also arise partly 
 from the inner surface of the fascia, where it covers them. 
 
 The deep fascia on the outer side of the leg is continuous 
 above, with the fascia lata, and is attached to the head of 
 the fibula ; laterally, it is attached to the tibia and fibula, 
 where it assists the anterior and posterior fasciae in forming 
 two intermuscular septa. This fascia forms a sheath for the 
 long and short peroneal muscles, and sends a process in be- 
 tween them from which, as well as from the inner surface of 
 the sheath, they, in part, have their origin; below, it termi- 
 nates in the external annular ligament. 
 
 The anterior annular ligament, Fig. 244 (12), consists of a 
 broad fibrous band extending superficially from the internal 
 malleolus and os naviculare obliquely across in front of the 
 ankle-joint to the external malleolus and os calcis. As the 
 deep fascia gradually increases in thickness as it approaches 
 the ligament, it is impossible to fix any distinct line of sepa- 
 ration between them. It forms on the inner side next to the 
 tibia a sheath for the tendon of the tibialis anticus, and an- 
 other for the tendons of the extensor longus digitorum com- 
 munis and peroneus tertius, which is placed lower down and 
 close to the fibula. The tendon of the extensor longus polli- 
 cis also passes through a sheath, which is, however, imperfectly 
 formed ; the anterior tibial vessels and nerve pass through 
 the same sheath occupied by the tendon of the extensor 
 longus pollicis. A fibrous band extends from the annular 
 
572 THE LOWER EXTREMITY. 
 
 ligament over the dorsum of the tarsus, and supplies the 
 tendons of the same muscles with sheaths, binding them 
 down at the same time to the tarsus, so that each is kept in 
 its proper position. This layer of fibrous structure is con- 
 tinuous laterally with the plantar fascia. The sheaths of 
 these tendons are lined by synovial membrane, which is also 
 reflected around the tendons themselves. 
 
 The external annular ligament, Fig. 244 (is), extends from 
 the external malleolus to the outer surface of the os calcis. 
 It forms a sheath for each of the peronei muscles, which pass 
 round the external malleolus. These sheaths, like the pre- 
 ceding, are lined by synovial membrane. The annular liga- 
 ments around the ankle-joint are extremely interesting, when 
 viewed as a part of the mechanism of the ankle and foot. 
 Without a knowledge of them it will be impossible for the 
 student to understand properly the actions of the muscles, 
 the tendons of which have a direction quite different from 
 that of those portions in which their contractile power lies. 
 
 There are four muscles on the anterior part of the leg, 
 which should now be exposed. To do this the deep fascia 
 may be divided by making a vertical incision, commencing 
 about three or four inches below the knee and about three- 
 fourths of an inch from the spine of the tibia, and extending 
 it down to the annular ligament, which should be preserved 
 for the present. The fascia should then be dissected laterally 
 from the muscles beneath it, so that its attachments to the 
 tibia and the fibula may be observed. Having done this, 
 the muscles should be separated from each other, which 
 should be done at first in the lower part of the leg where 
 they are free. When the tibialis anticus is separated from the 
 extensor longus digitorum communis below, the separation 
 can be extended upwards to their origin by dividing that por- 
 tion of the fascia, from the under surface of which they partly 
 arise. The fascia cannot be dissected from the upper part 
 of either of the above-mentioned muscles without mutilating 
 them, and leaving a rough surface formed by the cut ends of 
 the fibres. The fascia is here really a part of the muscle, 
 being a part of its tendon of origin in an aponeurotic form. 
 
 The TIBIALIS ANTICUS, Fig. 244 (3), is placed next to the 
 tibia, occupying the inner part of the anterior interosseous 
 fossa. It arises from the head of the fibula, from the inner 
 
Fig. 244. 
 
 ANTERIOR PAKT OF LEG, DOKSUM OF THE FOOT. 573 
 
 part of the interosseous ligament, from the head and the 
 outer surface of the upper two-thirds of the tibia, and from 
 the deep fascia. The fibres pass obliquely downwards and 
 inwards to end at the lower part of the leg in a flattish 
 round tendon, which passes down in front of the lower part 
 of the tibia and the ankle-joint to get to the inner side of the 
 tarsus, to be inserted into the tuberosity of the internal cunei- 
 form bone, and by a tendinous fascicu- 
 lus into the base of the metatarsal 
 bone of the great toe. The fibres join 
 the tendon much lower down behind 
 than before, so that in front the tendon 
 is seen as high as the junction of the 
 middle and lower thirds of the leg; 
 it extends considerably higher, but is 
 concealed by the fibres of the muscle. 
 It passes through a separate sheath 
 formed by the anterior annular liga- 
 ment, and is surrounded in the sheath 
 by synovial membrane. Its action is 
 to flex the foot upon the leg, to raise 
 the inner part of the foot, and also to 
 adduct it. As a flexor it antagonizes 
 the tibialis posticus, so that when the 
 student has learned its action as such, 
 he has merely to reverse it to under- 
 stand the action of the posticus. 
 
 The EXTENSOR LONGUS DIGITOKUM 
 PEDIS, Fig. 244 (4), is situated in the 
 outer part of the interosseous fossa, 
 having nearly the same relation to the 
 fibula that the preceding muscle has 
 to the tibia. The lower part of it is 
 separated from the fibula by the pero- 
 
 THE MUSCLES OF THE ANTERIOR TIBIAL REGION AND DORSUM OP THE FOOT. 
 1. The extensor muscles inserted into the patella. 2. The subcutaneous surface of 
 the tibia. 3. The tibialis anticus. 4. The extensor longug digitorum. 5. The ex- 
 tensor proprius pollicis. 6. The peroneus tertius. 7. The peroneus longus. 8. 
 The peroneus brevis. 9, 9. The borders of the soleus muscle. 10. A part of the 
 inner belly of the gastrocnemius. 11. The extensor brevis dig-itorum; the tendon 
 in front of this number is that of the peroneus tertius, and those behind it, the ten- 
 dons of the peronei brevis and longus. 12. Anterior annular ligament. 13. Ex- 
 ternal annular ligament. 14. Ligamentum patellae. 
 
574 THE LOWER EXTREMITY. 
 
 neus tertius, which on the leg appears to be a part of this 
 muscle. It arises from the outer part of the head of the 
 tibia, from the whole of the inner surface of the upper half 
 of the fibula including the head, from the interosseous liga- 
 ment, and from the interrnuscular septum on each side, and 
 the deep fascia of the leg in front. The fibres from these 
 different origins pass downwards, some obliquely and others 
 vertically, to end in a tendon near the junction of the middle 
 and lower thirds of the leg. This tendon immediately di- 
 vides into three others, which pass through a single canal 
 under the annular ligament, and then continue forwards on 
 the dorsum of the tarsus, the external one dividing into two to 
 reach the outer four toes, into the last two phalanges of which 
 they are inserted. If the upper part of this muscle be de- 
 tached from the fascia which covers it and the intermuscular 
 septa on its sides, the surfaces thus formed will be very 
 rough. On the dorsum of the foot, the four tendons cross 
 over at an acute angle, from within outwards, the tendons of 
 the short extensor of the toes ; each tendon spreads out on 
 the dorsum of the first phalangeal bone, which it passes over 
 to divide at the articulation of this bone with the second, 
 into three parts, the middle one of which is inserted into the 
 base of the second phalangeal bone, while the other two pass 
 forwards, to be inserted in common into the base of the last 
 phalangeal bone. The action of this muscle is to extend the 
 toes with which it is connected, and to flex the foot on the 
 leg ; it may also assist the tibialis anticus in inverting the 
 sole of the foot. 
 
 The PERONEUS TERTIUS, Fig. 244 (e), is placed to the 
 outer side of the preceding muscle, of which it not unfre- 
 quently seems to be a part. It arises from the anterior and 
 inner part of the lower half of the fibula, soon forms a ten- 
 don which passes downwards through the same canal under 
 the annular ligament as the extensor longus digitorum ; it 
 then descends obliquely outwards over the tarsus to reach 
 the base of the fifth metatarsal bone, into which it is inserted. 
 A tendinous band sometimes connects the tendon of this 
 muscle with the outer tendon of the preceding muscle. Its 
 principal action is to elevate the outer border of the foot; 
 in this way it may antagonize the action of the long ex- 
 tensor muscles of the toes, as far as those muscles may tend 
 
ANTERIOR PART OF LEG, DORSUM OF THE FOOT. 575 
 
 to invert the sole of the foot; it may also assist in extend- 
 ing the fifth toe, or in flexing the foot on the leg. 
 
 The EXTENSOR POLLICIS PROPRIUS, Fig. 244 (/>), is placed 
 between the tibialis anticus on the inner side, and the exten- 
 sor longus digitorum on the outer side; the upper part of 
 it is covered by these muscles. It arises from the inner 
 surface of the fibula, commencing usually as high as the 
 junction of the upper and middle thirds, and from the inter- 
 osseous ligament close to the fibula; it may also be joined by 
 a few fibres which arise from the lower part of the tibia. 
 The fibres terminate in a tendon which, commencing higher 
 in front than behind, passes first under the annular ligament, 
 then forwards over the tarsus and the metatarsal bone of the 
 great toe, to be inserted by two fasciculi into the base of the 
 first phalangeal bone, and by one fasciculus into the base of 
 the second phalangeal bone. Its relations to the anterior 
 tibial artery are interesting, and will be noticed in the de- 
 scription of that vessel. Its action is to extend the great 
 toe, and to flex the foot on the leg; it may also assist in 
 raising the inner border of the foot. 
 
 The EXTENSOR BREVIS DIGITORUM, Fig. 244 (i i), is placed 
 on the dorsum of the foot, being the only muscle in that re- 
 gion, except the interossei, that has its origin and insertion on 
 the foot. It arises on the outer part of the foot from the os 
 calcis and astragalus by a short round tendon and some mus- 
 cular fibres. It passes obliquely forwards and inwards be- 
 neath the tendons of the extensor longus digitorum and pe- 
 roneus tertius to divide into four tendons, which are continued 
 forwards to be inserted into the phalangeal bones of the inner 
 four toes, the little toe having no tendon from this muscle. 
 The one to the great toe is larger than either of the others ; 
 it passes over the dorsal artery of the foot just before it enters 
 the first interosseous space, and under the tendon of the long 
 extensor of the great toe, and is inserted into the base of the 
 last phalangeal bone of the great toe. The other tendons get 
 beneath the corresponding tendons of the long extensor of the 
 toes, and become blended with them in forming the fibrous 
 sheaths which cover the dorsa of all the smaller toes. The 
 action of this muscle is to extend the toes. Its direction 
 being obliquely from without inwards it counteracts the 
 tendency of the long extensors to draw the toes towards the 
 
576 
 
 THE LOWER EXTREMITY. 
 
 inner side of the leg, so that by their combined action the 
 toes will be extended in a line directly backwards. 
 
 Having now examined the muscles on the anterior part of 
 the leg and dorsum of the foot, the deep vessels and nerves 
 found in this region should next be 
 Fig. 245. noticed. To do this it will not, how- 
 
 ever, be necessary to raise the muscles, 
 for they can be pushed sufficiently to 
 one side or the other to get to the 
 vessels or nerves. The anterior tibial 
 artery and veins, with their branches, 
 are the only vessels; the anterior tibial 
 and the muscular cutaneous, for a short 
 distance, are the only nerves. 
 
 The ANTERIOR TIBIAL ARTERY, 
 Fig. 245 (3 ,4 , s), is one of the divisions 
 of the popliteal artery. It passes im- 
 mediately through an opening in the 
 upper part of the interosseous liga- 
 ment, to get into the anterior interos- 
 seous fossa or space, in which, resting 
 on the anterior surface of the interos- 
 seous ligament, it passes downwards 
 to the ankle-joint, where it terminates 
 in the dorsal artery of the foot. It is 
 placed, in the upper third of its course, 
 between the tibialis anticus and the 
 extensor longus digitorurn ; below this, 
 down to about the middle of the lower 
 third, it is found between the last- 
 named muscle and the extensor pol- 
 licis proprius, while in the remainder 
 of its course it is placed, at first, be- 
 hind the tendon of the extensor poll- 
 
 A VIEW or THE ANTERIOR TIBIAL ARTERY AND ITS BRANCHES. 1, 1, 1. The re- 
 mains of the extensor proprius pollicis pedis muscle and tendon. 2, 2, 2, 2. Super- 
 ficial branches from the popliteal artery, known as articular arteries. 3. Anterior 
 tibial artery, as it comes through the interosseous ligament. 4. The same artery, 
 on the middle of the leg. 5. Point where it passes under the extensor proprius 
 tendon above the annular ligament. 6. Anterior recurrent branch. 7. Branch to 
 the extensor comrnunis, soleus, and peroneus longus muscles. 8, 8, 8. Other mus- 
 cular branches. 9. Arteria dorsalis pedis, or continuation of the anterior tibial on 
 the foot. 10. A branch of the external malleolar artery. 
 
ANTERIOR PART OF LEG, DORSUM OF THE FOOT. 577 
 
 icis, and then between it and the extensor longus digi- 
 torum. 
 
 Thus, it will be seen that the extensor pollicis is placed at 
 first to the outer side, then in front, and lastly to the inner 
 side of this artery, which, in the upper third of the leg, can 
 have no relation to this muscle whose origin begins at the 
 junction of the upper and middle thirds. The student should 
 notice the distance of this artery from the skin, as it descends 
 to the ankle, or the depth of an incision that would reach it 
 in any part of its course; he should also observe how far 
 from the spine of the tibia, and in what direction an incision 
 should be made, for the purpose of ligating it in the living 
 subject. Besides muscular branches which are not named, 
 the anterior tibial artery gives off the anterior tibial recurrent, 
 and an external and an internal malleolar branch. 
 
 The anterior tibial recurrent branch, Fig. 245 (G), arises from 
 the anterior tibial artery as soon as it has reached the ante- 
 rior interosseous space. It passes upwards and inwards on 
 the surface of the inner tuberosity of the head of the tibia, 
 covered by the origin of the tibialis anticus; it then divides 
 into branches, which anastomose with the inferior external 
 and internal articular branches of the popliteal artery. 
 
 The internal malleolar branch, Fig. 246 (i o), arises just above 
 the anterior annular ligament, passes inwards and down- 
 wards beneath the tibialis anticus, and divides into two 
 branches, one of which enters the ankle-joint, while the other 
 passes over the surface of the internal malleolus, below which, 
 on the inner side of the foot, it anastomoses with branches of 
 the internal plantar artery. 
 
 The external malleolar branch, Fig. 246 (i i), usually arises 
 near the anterior annular ligament ; it varies, however, very 
 much in its origin and distribution, and also in its size. It 
 is distributed on the outer part of the foot, anastomosing 
 with branches of the peroneal artery externally and with 
 branches of the dorsal artery of the tarsus inferiorly; it 
 usually gives off quite a large branch to the articulation of 
 the ankle. 
 
 The dorsal artery of the foot, Fig. 246 (7, 9), commences at the 
 anterior annular ligament, being a continuation of the ante- 
 rior tibial, and extends forwards on the tarsus to the first 
 interosseous space, into which it dips to join the external plan- 
 49 
 
578 THE LOWER EXTREMITY. 
 
 Fig. 246. Fig. 247. 
 
 THE SUPERFICIAL ARTERIES ON 
 
 THE TOP OF THE FOOT. 1. Tibi.llis 
 
 anticus muscle. 2. Extensor proprius 
 pollicis pedis. 3. Extensor comrnu- 
 nis tendon, cut off. 4. Extensor bre- 
 vis digitorum pedis. 5. Anterior 
 tibial artery, between the extensor 
 tendons. 6. Some of its muscular 
 branches. 7. Opposite to commence- 
 ment of dorsal artery. 8. Opposite 
 to dorsal artery of the foot. 9. Point 
 where it dips to anastomose with the 
 external plantar. 10, 11. Two mal- 
 leolar arteries. 12, 13. Muscular 
 branches of the dorsal artery of the 
 foot. 14. Metatarsal artery. 15, 16, 
 17. Its interosseal branches and their 
 distribution. 
 
 THE DEEP-SEATED ARTERIES ON THE TOP 
 OF THE FOOT. 1. Point where the anterior 
 tibial reaches the foot. 2. Dorsal artery 
 of the foot. 3. Pointwhere it dips, to join 
 the plantar arch. 4. Internal malleolar 
 artery. 5. Dorsal artery of the tarsus. 6. 
 A branch to the extensor brevis muscle. 
 7. Branches of the dorsal artery. 8. 
 Branches to the ligaments. 9. Metatarsal 
 artery. 10. Superior branches of the meta- 
 tarsal artery. 11. Interosseous arteries. 
 12. Posterior perforating branches of the 
 metatarsal. 13. Plantar interosseous arte- 
 ries, seen through the interosseous spaces. 
 14. Anterior perforating branches of the 
 metatarsal. 35. Bifurcation of the inter- 
 osseous to give the digital of the toes. 16. 
 Dorsalis pollicis. 17. A digital branch 
 to the inside of the great toe. 18. Bifur- 
 cation of the dorsalis pollicis. 19. Its 
 perforating branch. 20, 21, 22. Distribu- 
 tion of the digitals.' 23. Section of the 
 posterior tibial. 24. Branch of the poste- 
 rior peroneal artery. 
 
 tar artery. It lies to the outer side of the tendon of the ex- 
 tensor of the great toe, and is covered by the skin, the super- 
 ficial and the deep fascia. It gives off several branches; those 
 
ANTERIOR PART OF LEG, PORSUM OF THE FOOT. 579 
 
 which, are directed to the inner part of the foot are not 
 named; they vary in number, size, and distribution. They 
 anastomose behind with the internal malleolar branch of the 
 anterior tibial artery, and below with branches of the inter- 
 nal plantar ; those which go to the dorsum of the outer part 
 of the foot are the following: 
 
 The dorsal artery of the tarsus, Fig. 247 (s), passes outwards 
 beneath the extensor brevis digitorum and divides into 
 several branches, which anastomose with the external mal- 
 leolar branch of the anterior tibial, with the external plantar 
 artery, and with the one next to be described. It varies in 
 size and in the number of branches which it gives off. 
 
 The metatarsal branch, Fig. 247 (9), usually arises just be- 
 fore the dorsal artery of the foot disappears in the interos- 
 seous space. It passes transversely outwards in a line cor- 
 responding nearly to the tarso-metatarsal articulations, forming 
 an arch from which branches are given off to supply the in- 
 terosseous spaces and the integument on the upper part of 
 the toes. They are called the interosseous and digital arteries. 
 There is one for each of the interosseous spaces except the 
 first, which is supplied directly from the dorsal artery of the 
 foot. Each interosseous artery divides into two digital 
 branches, which are distributed to the opposing sides of the 
 two toes which correspond to the artery. The relations and 
 distribution of the three interosseous arteries are very nearly 
 similar. They anastomose with branches of the correspond- 
 ing arteries on the bottom of the foot. Each interosseous 
 artery is joined by an anastomosing branch at each extremity 
 of the interosseous space. 
 
 The DEEP VEINS consist of those which accompany the 
 arteries, each artery having its vence comites. They commu- 
 nicate with the superficial or subcutaneous veins at different 
 points. The venae comites are generally arranged so as to 
 have one on the outer and one on the inner side of the artery 
 which they accompany ; they communicate freely with each 
 other by means of branches extending between them across 
 the artery. The deep veins are supplied with valves. 
 
 The ANTERIOR TIBIAL NERVE, Fig. 248 (2, 3), is one of the 
 terminal divisions of the external popliteal or peroneal, which 
 it leaves between the peroneus longus and the external sur- 
 
580 
 
 THE LOWEK EXTREMITY. 
 
 face of the fibula just below its head ; it then passes beneath 
 the flexor longus digitorum, getting be- 
 Fig. 248. tween it and the tibialis anticus, where it 
 
 joins the anterior tibial artery which it 
 accompanies down the leg to the foot, 
 being placed in front of it. Just before 
 the external popliteal nerve divides into 
 the musculo-cutaneous and the anterior 
 tibial it gives off a small branch to the 
 tibialis anticus muscle, and another to 
 the tibio-fibular articulation. Below the 
 anterior annular ligament the anterior 
 tibial nerve divides into two branches; 
 one of which accompanies the dorsal ar- 
 tery to the first interosseous space, where 
 it divides into two branches which are 
 distributed, one to the two sides of the 
 great toe, and the other to the inner side 
 of the second toe. These last branches 
 either anastomose with or take the place 
 of the corresponding branches of the 
 musculo-cutaneous nerve. The other 
 terminal division of the anterior tibial 
 passes obliquely outwards beneath the 
 short common extensor of the toes, and 
 divides into several branches, some of 
 which go to that muscle, while others 
 are distributed to the interosseous spaces. 
 
 The Musculo- Cutaneous Nerve, Fig. 248 
 (i), will be seen in the dissection of the 
 muscles on the anterior part of the leg, 
 only while passing between the peroneus 
 longus and the flexor longus digitorum 
 muscles; below this it perforates the deep 
 fascia and becomes subcutaneous, which 
 part of it has already been described in 
 the superficial fascia. In the first part of 
 its course it passes through the substance 
 of the peroneus longus, and must be exa- 
 mined when that muscle is dissected. 
 
 On the outer part of the leg will be found the peronei 
 
 A VIEW OF THE MUS- 
 CTJLO-CUTANEOUS AND 
 THE ANTERIOR TIBIAL 
 NERVE. 1. The mus- 
 culo-cutaneous nerve. 2, 
 3. The anterior tibial 
 nerve accompanying the 
 artery of the same name. 
 
OUTER PART OF LEG, DORSUM OF THE FOOT. 581 
 
 muscles, long and short. They cover the whole of the ex- 
 ternal surface of the fibula except about two inches and a 
 half at the lower end, where the bone is subcutaneous, and 
 can be distinctly felt beneath the skin. When compared with 
 the tibia, the fibula will be seen to have but little subcutaneous 
 surface ; it gives origin or attachment to muscles on every 
 side, while but two of the three sides of the tibia are thus 
 occupied. The fibula belongs essentially to the foot, the tibia 
 to both the thigh and foot, perhaps more r however, to the 
 former than to the latter. Only one muscle passes over the 
 knee-joint to be attached to the fibula, while nine will be 
 found passing over it to be attached to the tibia; the reverse 
 is true to some extent of the attachments of those muscles to 
 the tibia and fibula which pass over the ankle-joint to the foot. 
 The musculo-cutaneous nerve, Fig. 248 (i), one of the termi- 
 nal divisions of the external popliteal, should now be sought 
 in the substance of the peroneus longus, in order that it may 
 be traced through this muscle to the space between it and the 
 extensor longus digitorum. This nerve was noticed in the 
 dissection of the superficial fascia and muscles on the anterior 
 part of the leg, and on the dorsum of the foot; it only remains 
 now to examine it in its course through the peroneus longus, 
 and the branches which it gives off to the peronei muscles. 
 
 The PERONEUS LONGUS, Fig. 244 (7), arises from the ante- 
 rior and outer surface of the head of the fibula, from a small 
 portion of the external surface of the head of the tibia, from 
 the outer surface of the upper half of the fibula below the 
 head, from the intermuscular septum on each side of it, and 
 from the fascia which covers it. From these different points 
 of origin the fibres pass downwards to end in a ribbon-shaped 
 tendon near the middle of the leg, where it is closely applied 
 to the peroneus brevis ; becoming narrower, the tendon de- 
 scends to the groove behind the external malleolus, where it 
 passes under the external annular ligament in a canal with the 
 short peroneus; it then turns forwards to a groove on the 
 outer border of the cuboid bone, through which it passes to 
 enter the sole of the foot; from this point it is directed ob- 
 liquely forwards and inwards to the base of the metatarsal 
 bone of the great toe, into which it is inserted, Fig. 266 (s). 
 It is covered by ligamentous fibres at the outer border of 
 the cuboid bone, and also in the sole of the foot; these fibres 
 
582 THE LOWEE EXTREMITY. 
 
 form a sheath for it at each place, lined by a synovial mem- 
 brane; the canal through which it passes behind the external 
 malleolus is also lined by a synovial membrane. It will be 
 seen that the tendon of this muscle passes over two trochlear 
 surfaces, one behind the malleolus from which it is reflected 
 forwards and downwards, the other at the outer border of the 
 cuboid bone where it is reflected forwards and inwards. A 
 sesamoid bone is frequently found in the tendon where it 
 passes over the cuboid bone. The action of this muscle is to 
 extend the foot on the leg and to depress the inner border of 
 the foot, elevating at the same time the outer border. The 
 examination of the tendon of this muscle in the sole of the 
 foot must be postponed until the parts which cover it there 
 have been dissected. 
 
 The PERONEUS BREVIS, Fig. 244 (e), arises from the exter- 
 nal surface of the lower half of the fibula, and from the inter- 
 muscular septum on each side of it ; its tendon commencing 
 a short distance above the external malleolus, but lower than 
 that of the peroneus longus, descends to the groove behind 
 the malleolus where it passes through the same canal as the 
 preceding muscle; it is then continued forwards and down- 
 wards through a groove on the outer side of the os calcis to 
 the base of the metatarsal bone of the little toe, into which it 
 is inserted; sometimes it is connected by a few fibres to the 
 cuboid bone or to the base of the fourth metatarsal bone, or 
 it may send a slip to the extensor tendon of the little toe. 
 On the outer side of the fibula and behind the external mal* 
 leolus it is placed beneath the peroneus longus, but is above 
 it on the outer side of the os calcis, where it is surrounded by 
 a synovial membrane. Its action is the same as that of the 
 peroneus longus. These muscles should be examined with 
 reference to fracture of the fibula, and, also, to displacement 
 of their tendons, by being forced out of the canal through 
 which they pass, behind the external malleolus. 
 
 SECT. YI. DISSECTION OF THE SOLE OF THE FOOT. 
 
 The anatomy of the sole of the foot demands the careful 
 attention of the student. Its arteries and nerves, from their 
 
DISSECTION" OF THE SOLE OF THE FOOT. 583 
 
 exposed situation, are constantly liable to injury, especially 
 among the poorer classes of people, who are in the habit of dis- 
 pensing with the use of shoes or boots. Punctured wounds 
 are frequently met with in the sole of the foot, which, are 
 liable to be followed by tetanus, or by collections of pus; in 
 either case, the proper treatment must be based mainly on the 
 anatomy of the parts. The same is true in the case of incised 
 wounds, in which hemorrhage occurs, requiring the employ- 
 ment of prompt and efficient means for arresting it. Deformi- 
 ties are also met with, in the treatment of which a thorough 
 knowledge of the foot is demanded. And the same may be 
 said in regard to injuries of various kinds, requiring surgical 
 treatment. The question, as to the removal of a part or the 
 whole of the foot by excision or amputation, must frequently 
 be decided by the extent of injury which the parts have sus- 
 tained ; and, to be able to determine this, the surgeon must 
 have an accurate knowledge of all the parts involved. In the 
 management of such cases, the surgeon cannot rely on any 
 rules which he may have learned in the lecture-room or in 
 books; for it is impossible to lay down any set of rules which 
 will meet the indications of every case that may occur. Whe- 
 ther the patient shall lose the whole or a part of his foot, or 
 shall have the limb saved entire, may depend wholly upon a 
 slight variation in the extent of the injury inflicted, and which 
 can be detected only by the surgeon having a distinct idea of 
 all the parts, and their relations to each other, which enter 
 into the structure of the foot. 
 
 To dissect the sole of the foot, a block must be placed under 
 the instep, so that the foot can be fully extended on the leg, 
 with the plantar surface looking upwards; it must also be 
 firmly fixed in this position ; if this be neglected, the dissector 
 will be constantly annoyed by the foot moving about, its own 
 weight being insufficient to assist much in keeping it in the 
 position required, and the integument is so closely connected 
 to the aponeurosis or fascia beneath it, by numerous fibres 
 prolonged from its under surface and from the subcutaneous 
 adipose substance into the aponeurosis, that considerable force 
 is required to divide them in raising the skin. To be able to 
 make this dissection properly, the student must be provided 
 with sharp scalpels, otherwise he will almost necessarily, either 
 remove portions of the aponeurosis with the skin, or leave 
 
584 THE LOWER EXTREMITY. 
 
 more or less of the adipose substance attached to the apo- 
 neurosis. 
 
 The PLANTAR APONEUROSIS or FASCIA covers nearly the 
 whole of the under surface of the foot. It presents a pearly 
 white, shining appearance, which will enable the dissector to 
 distinguish it from the integument, and hence to know when 
 he has reached it in making the first incision through the skin, 
 or when, during the progress of the dissection, he is leaving 
 nothing but the aponeurosis. It is divided into a middle, an 
 external, and an internal portion ; the separation of these is 
 indicated by two shallow grooves or sulci, caused, as will be 
 seen, by the arrangement of the muscles which they cover. 
 
 The middle portion is thicker than either of the others. It 
 arises from the posterior inner tubercle on the under surface 
 of the os calcis, and extends to the metatarso-phalangeal ar- 
 ticulation, where it divides into four parts. It increases in 
 breadth from behind forwards, without, however, diminishing 
 much in thickness. Laterally, its borders project upwards 
 between the muscles which it covers and those covered by the 
 internal and external portions, with which it unites to form 
 two intermuscular septa; these are more perfect before than 
 behind. Each of the processes, into which it divides ante- 
 riorly, subdivides into two others, which are placed, one on 
 each side of the corresponding metatarso-phalangeal articu- 
 lation, so as to include between them the sheath and the 
 tendons, one of the short and the other of the long common 
 flexor of the toes, which pass through it; they terminate by 
 becoming attached to the sheath, and to the ligaments of the 
 joint. Laterally, the processes are united to each other so as 
 to form arches which correspond to the anterior extremities 
 of the interosseous spaces, and beneath which the digital ar- 
 teries and nerves, also the lumbricales and the interosseous 
 muscles, pass to reach the toes. For some distance from its 
 posterior attachment, its upper or deep surface is occupied 
 by the origin of a portion of the fibres of the flexor brevis 
 digitorum; this fact the student must bear in mind when he 
 comes to raise this portion of the aponeurosis; to do which, 
 it should be carefully divided transversely, about an inch and 
 a half from its origin, where it begins to be separated from 
 the muscle by areolar tissue; the portion behind this point 
 
DISSECTION OF THE SOLE OF THE FOOT. 585 
 
 cannot be raised except by detaching it from the fibres of the 
 muscle ; hence it may be left to be raised with the muscle. 
 
 The middle portion of the aponeurosis forms a common 
 sheath for the flexor brevis digitoram, flexor longus digito- 
 rum, flexor longus pollicis, musculus accessorius, the lumbri- 
 cales, and the plantar vessels and nerves. Being attached to 
 the posterior extremity of the tarsus, and anterior extremity 
 of the metatarsus, it greatly strengthens the arch of the foot 
 in an antero-posterior direction, and also in an opposite direc- 
 tion by some transverse fibres found. in the part immediately 
 below the metatarsus. It not only contributes to the strength 
 of the framework of the foot, and serves to keep the muscles, 
 for which it forms a sheath, in situ, but it protects the parts 
 above it. 
 
 The internal portion is thinner than the external, being so 
 thin anteriorly that considerable care is requisite to preserve 
 it when the integument is removed. Posteriorly, it is con- 
 nected to the internal annular ligament, or the ligamentous 
 arch that extends from the os calcis to the internal malleolus; 
 internally, it is partly attached to the inner border of the tar- 
 sus, and partly continuous with the dorsal fascia; externally, 
 if is joined to the middle portion, and assists in forming the 
 internal intermuscular septum. It forms a sheath, in part, for 
 the muscles of the great toe, and the plantar vessels and 
 nerves. Besides protecting the parts beneath it, it strength- 
 ens the inner part of the foot. 
 
 The external portion arises behind, from the external annular 
 ligament, or the ligamentous arch that extends from the ex- 
 ternal malleolus to the os calcis ; it is attached to the outer 
 border of the tarsus, where it is also continuous with the dor- 
 sal fascia. It forms, by its attachment to the cuboid bone and 
 the posterior extremity of the fifth metatarsal bone, a strong 
 ligamentous arch over the tendon of the peroneus longus 
 where it enters the sole of the foot; internally it is connected 
 to the external intermuscular septum, and to the middle por- 
 tion of the aponeurosis. It covers the abductor and flexor 
 brevis minimi digiti muscles. Its uses are similar to those of 
 the inner portion. 
 
 Having now exposed and studied the plantar aponeurosis, 
 it must be raised in order to examine the parts placed above 
 it. From what has already been said in describing the plan- 
 tar aponeurosis and the long flexor muscles, together with 
 
586 THE LOWER EXTREMITY. 
 
 the posterior tibial nerve and vessels on the back of the leg, 
 the student has obtained some idea of what he will find above 
 the aponeurosis. Two of the superficial muscles may be exa- 
 mined first, as this can be done not only without injuring the 
 vessels and nerves, but it will facilitate the dissection of them ; 
 of these, the following muscle may be first examined, as it 
 occupies the central part of the sole of the foot, and sustains 
 more important relations to the vessels and nerves than any 
 other in this region. It separates the grooves in which the 
 external and internal plantar arteries are found. 
 
 The FLEXOR BREVIS DIGITORUM PERFORATUS, Fig. 249 (5), 
 arises from the under surface of the posterior and inner part 
 of the os calcis, from the intermuscular septum on each side 
 of it, from the plantar fascia which covers its under surface, 
 and also from the internal annular ligament. From these 
 different points of origin it passes forwards to near the mid- 
 dle of the foot, where it divides into four small muscles, each 
 of which proceeds forwards a short distance and terminates 
 in a small tendon, which is continued to the base of the se- 
 cond phalangeal bone, where it divides into two slips, be- 
 tween which the corresponding tendon of the long common 
 flexor of the toes passes; the slips unite again, and, after 
 expanding laterally, are inserted into the under surface of the 
 second phalangeal bone. It corresponds, in the division of its 
 tendon, to the superficial common flexor of the forearm. It 
 is quite thick at its origin, where it is both fleshy and tendin- 
 ous, but increases in breadth towards the middle of the foot. 
 Its action is to flex the four outer toes; it may also strengthen 
 the middle aponeurosis in preserving the arch of the foot. 
 To expose this muscle, a transverse incision may be made 
 across the middle portion of the aponeurosis, as was before 
 mentioned, about an inch or an inch and a half anterior to 
 its origin, taking care not to divide anything but the aponeu- 
 rosis. The portion in front of the incision may next be 
 raised. To do this, it may be dissected from behind forwards, 
 detaching it from the intermuscular septum on each side ; or 
 it may be divided longitudinally into four portions, so that 
 each shall correspond to one of the four processes into which 
 the aponeurosis divides anteriorly, and then dissect each por- 
 tion to its subdivision into its two slips, and their attachments 
 to the sheath of the tendons of the short and long common 
 
DISSECTION OF THE SOLE OF THE FOOT. 587 
 
 Fig. 249. 
 
 flexors of the toes. In doing this, unless the dissection is very 
 carefully made, one or more of the small delicate tendons of 
 the short common flexor will be destroyed. This is very apt to 
 occur in the first dissection which the student makes of these 
 parts. The aponeurosis, behind the first incision that was 
 made, can easily be separated on the sides, but not on the 
 under surface of the muscle. There is no necessity, however, 
 for raising this part of it, as it can be raised with the muscle. 
 To raise the muscle it may be detached from the bone and 
 reflected forwards, or it may be divided near its centre and 
 turned, part of it backwards and part of it forwards. The 
 abductor pollicis may next be exposed. The internal apo- 
 neurosis should be removed by dissecting it off in the direc- 
 tion of the fibres of the abductor muscle. 
 
 The ABDUCTOR POLLICIS, Fig. 249 (s), 
 arises from the os calcis, from the in- 
 ternal annular ligament, from the plantar 
 aponeurosis, and from the intermuscular 
 septum between it and the flexor brevis 
 digitorum. It passes forwards to end in 
 a tendon which is inserted, in common 
 with the internal division of the flexor 
 brevis, into the base of the first phalan- 
 geal bone of the great toe. Its action, as 
 its name implies, is to separate the great 
 toe from the others; it may also assist in 
 flexing the great toe. This muscle may 
 now be turned over, but in doing so some 
 care is necessary to avoid injuring the 
 plantar vessels and nerves which pass 
 under that portion of it which arises 
 from the os calcis and the annular liga- 
 ment. They can be easily preserved 
 and traced beneath the origin of this 
 muscle, if the vessels and nerves on the 
 
 THE FIRST LAYER OF MUSCLES IN THE SOLE OF THE FOOT ; THIS LAYER is EX- 
 POSED BY THE REMOVAL OF THE PLANTAR FASCIA. 1. The OS Calcis. 2. The pOS- 
 
 terior part of the plantar fascia divided transversely. 3. The abductor pollicis. 
 4. The abductor minimi digiti. 5. The flexor brevis digitorura. 6. The tendon 
 of the flexor longus pollicis muscle. 7, 7. The lumbricales. On the second and 
 third toes, the tendons of the flexor longus digitorum are seen passing through the 
 bifurcation of the tendons of the flexor brevis digitorum. 
 
588 THE LOWER EXTREMITY. 
 
 back of the leg have not been destroyed. The posterior tibial 
 artery has been seen to bifurcate at a point about midway 
 between the internal malleolus and the os calcis. From this 
 bifurcation the external and internal plantar arteries pass for- 
 wards and outwards to enter the sole of the foot. 
 
 The internal plantar artery, Fig. 250 (4), gets into the sulcus 
 between the abductor pollicis and flexor brevis digitorum 
 muscles, and passes forwards to the anterior part of the first 
 interosseous space, where it usually terminates by sending 
 one, and sometimes two branches, to the great toe. In its 
 course it gives off branches to the muscles, to the integu- 
 ment, and to anastomose with branches of the dorsal artery 
 of the foot. 
 
 The external plantar artery, Fig. 251 (s, e), when it has reached 
 the sole of the foot, turns outwards and forwards beneath the 
 flexor brevis digitorum, and thus gets into the sulcus between 
 the flexor brevis digitorum and the abductor minimi digiti, in 
 which it continues for a short distance, then turns inwards 
 across the second and third metatarsal bones and interosseous 
 spaces, to reach the first interosseous space, where it anasto- 
 moses with the dorsal artery of the foot. The anterior curved 
 portion of it is called the plantar arch. At first, it passes, as 
 has already been seen, under the abductor pollicis, then through 
 the posterior part of the internal groove where it can be 
 reached without dividing any muscle ; it then passes under 
 the flexor brevis digitorum and enters the external groove 
 where it can again be reached without cutting through any 
 muscle ; as it leaves the groove it becomes deep-seated, get- 
 ting between the tendons and the common flexor muscles of 
 the toes and the interosseous muscles ; so that in its course 
 it is in three places situated beneath muscles, and in two 
 places subaponeurotic. In the first and the middle part of its 
 course, it gives branches to the integument on the heel, to mus- 
 cles, and to the tarsal articulations, also to anastomose with the 
 tarsal and metatarsal branches of the dorsal artery of the 
 foot. Two sets of branches are given off from the arch. 
 The posterior perforating branches, three in number, pass up- 
 wards through the second, third, and fourth interosseous 
 spaces, and anastomose with the corresponding interosseous 
 arteries on the dorsum of the foot. The anterior or digital 
 arteries, Fig. 251 (14), four or five in number, pass forwards 
 to supply the toes; at the anterior extremities of the inter- 
 
DISSECTION OF THE SOLE OF THE FOOT, 
 Fig. 250. Fig. 251. 
 
 589 
 
 THE DEEP-SEATED BRANCHES OF THE AR- 
 
 TERIES ON THE SOLE OF THE FOOT. 1. Poste- 
 rior tibial artery by the side of the astragalus. 
 2. Branches to the os calcis. 3. Branch of 
 the posterior peroneal artery. 4. Bifurcation 
 of the posterior tibial into the internal and 
 external plantar. 5. The external plantar 
 artery. 6. Point where it forms the plantar 
 arch. 7. Anastomosis of the anterior tibial 
 with the plantar arch. 8, 9, 10. Muscular 
 branches of the external plantar artery. 11. 
 Anastomosis of this artery with the metatarsal. 
 12, 13. External digital of the little toe. 14. 
 Digital arteries of the other toes. 15, 15, 1 5, 15. 
 Their distribution on the toes. 16. Origin of 
 the internal plantar artery. 17. Its anasto- 
 mosis with the plantar arch. 18,19, 20. Mus- 
 cular branches of the internal plantar artery. 
 21. Digital of the great toe, or arteria magna 
 pollicis, as formed by the anastomosis of the 
 internal plantar and plantar arch. 22. Sub- 
 articular branch of the great toe. 23. Anasto- 
 mosis in the pulp of the toe. 
 
 osseous spaces, each artery gives off an anterior perforating 
 branch which passes upwards through an interosseous space, 
 and anastomoses with a corresponding interosseous branch. 
 50 
 
 A VIEW OF THE ARTERIES ON 
 THE BACK OF THE RlGHT LEG AND 
 THEIR CONTINUATION ON TO THE 
 SOLE OF THE FOOT. 1, 1, 1, 1. 
 Tendons of the flexor communis 
 and flexor longus pollicis pedis. 
 
 2. Tendon of the peroneus longus. 
 
 3. Posterior tibial artery at the 
 ankle. 4, 4. External and internal 
 plantar arteries. 5. Points where 
 the external plantar dips to form 
 the plantar arch. 6. Peroneal ar- 
 tery, just above the origin of the 
 external malleolar branch. 7. A 
 branch to anastomose with the 
 posterior tibial. 8. Just above the 
 division of the peroneal artery 
 into its anterior and posterior 
 branches. 
 
590 
 
 THE LOWER EXTREMITY. 
 
 252. 
 
 The digital branches then divide, each into an internal and 
 external collateral branch to go to the toes; these pass forwards 
 on the opposing sides of contiguous toes. There is but one 
 that goes to the outer part of the little toe. The arteria magna 
 pollicis arises near the anastomosis of 
 the plantar arch with the dorsal artery, 
 and supplies the outer side of the great 
 toe, and the inner side of the second toe. 
 The veins accompany the arteries, 
 there being two for each artery. They 
 anastomose with the dorsal veins along 
 the inner and outer borders of the foot. 
 As they leave the sole of the foot they 
 unite to form the posterior tibial vein. 
 The nerves of the sole of the foot 
 are derived from the posterior tibial 
 which divides behind the internal 
 malleolus into the external and inter- 
 nal plantar. 
 
 The internal plantar nerve, Fig. 252 
 (4), passes along the inner side of the 
 os calcis and above the abductor pol- 
 licis in company with the artery of the 
 same name, and gets into the internal 
 sulcus or groove, in the anterior part 
 of which it divides into four digital 
 A VIEW OF THE TERMINA- Ranches which supply the great the 
 ON OF THE PosTEiuoR Ti- second, the third, and the inner side of 
 AL NERVE IN THE SOLE OF the fourth toe. Its distribution to the 
 
 THE JbooT. 1. Inner side ot , ,-, . n p A -, -.. 
 
 the foot. 2. Outer side of the toes is the same as that oi the median 
 foot. 3. The heel. 4. in- nerve is to the fingers. In the anterior 
 Pt of its course, it perforates the 
 sheath, in which the flexor breyis digi- 
 P laced - and continues for a 
 
 Branch to the flexor bre 
 
 Branch to the space between short distance along the inner border 
 ?o o ur i? -* ai ! d i m \ to f of tliat muscle. It gives off several 
 
 9, 9. 9. Digital branches to , , , n 
 
 the remaining spaces. 10. branches to the muscles and tO the Ill- 
 
 Branch to the internal side tegument before it divides into its ter- 
 minal branches. Near its origin, it 
 sends quite a large branch to the integument on the heel. 
 The external plantar nerve. Fig. 252 (5), accompanies the 
 
DISSECTION OF THE SOLE OF THE FOOT. 591 
 
 external plantar artery above the short common flexor, and 
 in the external sulcus as far as the commencement of the 
 plantar arch, where it divides into a superficial and a deep- 
 seated branch. The superficial branch, which is cutaneous, is 
 distributed to the little toe, supplying both sides of it, and to 
 the outer part of the fourth toe. The deep branch passes in- 
 wards and upwards across the metatarsus, forming an arch 
 similar to that formed by the external plantar artery ; it is 
 distributed to the deep muscles. Frequently, it sends quite 
 a large branch to anastomose with the internal plantar. It 
 also sends filaments to the articulations of the tarsus and 
 metatarsus. 
 
 The FLEXOR BREVIS POLLICIS, Fig. 254 (5), arises from an 
 aponeurosis which partly covers it, from the inner margin of 
 the cuboid bone, from the external cuneiform, and from the 
 tendon of the tibialis posticus. It divides into two bellies, 
 which are inserted by short tendons into the sides of the base 
 of the first phalangeal bone. A sesamoid bone is generally 
 found in each of its tendons. The tendon of the long flexor 
 of the great toe is placed between its bellies. 
 
 The FLEXOR ACCESSORIUS or MASSA CARNEI JACOBI SYL- 
 VII, Fig. 253 (s), arises by two heads; one, larger than the other, 
 from the inner side of the os calcis, and the other from the un- 
 der and anterior surface of the same bone; from these origins, 
 the two heads pass forwards, soon uniting to form a single 
 belly which is inserted into the outer, upper, and lower sur- 
 faces of the tendon of the flexor longus digitorum just before, 
 or as it divides into its four tendons. Its action is to assist 
 the long flexor in flexing the toes, and to give a direction 
 to the action of that muscle parallel to the axis of the foot. 
 The connection between the tendons of the long common 
 flexor of the toes and the long flexor of the great toe should 
 now be examined, and their tendons dissected. 
 
 The LUMBRICALES, Fig. 253 (4, 4), are four small muscles, 
 which arise from the four tendons of the long common flexor 
 near its division, and, passing along the inner side of them, 
 each ends in a small flat tendon, which is inserted into the inner 
 and dorsal surface of the first phalangeal bone, where it also 
 joins the tendon of the long extensor of the toes. The action 
 of these muscles is to adduct and assist in flexing the toes, 
 
592 
 
 THE LOWEE EXTREMITY. 
 
 with which they are connected; when the toes are partly 
 extended, they can assist in extending them further. These 
 muscles, together with the tendons of the long flexors, may 
 now be removed. 
 
 Fig. 253. 
 
 Fig. 254. 
 
 DEEP-SEATED MUSCLES IN THE 
 SOLE OF THE FOOT. 1. Tendon of 
 the flexor longus pollicis. 2. Ten- 
 don of the flexor communis digito- 
 rum pedis. 3. Flexor accessorius. 
 4, 4. Luinbricales. 5. Flexor brevis 
 digitorum. 6. Flexor brevis pollicis 
 pedis. 7. Flexor brevis minimi di- 
 giti pedis, including the abductor 
 minimi digiti. 
 
 THE THIRD AND A PART OF THE SECOND 
 LAYER OF MUSCLES ON THE SOLE OF THE 
 FOOT. 1. The divided edge of the plantar 
 fascia. 2. The flexor accessorius. 3. 
 The tendon of the flexor longus digitorum. 
 
 4. The tendon of the flexor longus pollicis. 
 
 5. The flexor brevis pollicis. 6. The ad- 
 ductor pollicis. 7. The flexor brevis minimi 
 digiti. 8. The transversus pedis. 9. Inter- 
 ossei muscles, plantar and dorsal. 10. Con- 
 vex ridge formed by the tendon of the pero- 
 neus longus muscle in its oblique course 
 across the foot. 
 
 The ADDUCTOR POLLICIS, Fig. 254 (e), arises from the cu- 
 boid bone and the long calcaneo-cuboid ligament, from the 
 posterior extremities of the second, third, and fourth meta- 
 tarsal bones, and from the sheath of the peroneus longus. It 
 passes from these different origins obliquely inwards to be in- 
 
DISSECTION OF THE SOLE OF THE FOOT. 593 
 
 serted, in common with the external head of the flexor b re vis 
 pollicis, into the outer part of the base of the first phalangeal 
 bone of the great toe. Its action is to draw the great toe 
 outwards towards the other toes ; it may also, with the outer 
 division of the flexor brevis pollicis, draw it downwards and 
 outwards under the other toes. 
 
 The TRANSVERSALIS PEDIS, Fig. 254 (s), arises from the 
 anterior extremities of the metatarsal bones of the four outer 
 toes, passes transversely inwards between the flexor and inter- 
 osseous muscles, to be inserted into the outer sesarnoid bone 
 with the adductor pollicis. Its action is to draw the outer toes 
 towards the great toe, and prevent the metatarsal bones from 
 spreading. 
 
 The ABDUCTOR MINIMI DIGITI, Fig. 253 (7), arises from the 
 external and inferior surface of the os calcis and the aponeu- 
 rosis, which covers it ; it passes forwards along the external 
 border of the foot, and is inserted into the outer part of the 
 base of the first phalangeal bone of the fifth toe. Its action 
 is to separate the little toe from the others, and to assist in 
 flexing it. 
 
 The FLEXOR BREVIS MINIMI DIGITI, Fig, 256 (3), arises 
 from the sheath of the tendon of the peroneus longus muscle, 
 from the cuboid and the fifth metatarsal bone, and, passing 
 forwards and a little outwards, is inserted into the base of the 
 first phalangeal bone of the little toe. Its action is to draw 
 the little toe towards the others, and to assist in flexing it. 
 
 There are seven interosseous muscles, three of which are 
 plantar or inferior, suadfour dorsal or superior. They are found 
 in the interosseous spaces, except the plantar, which are placed 
 more or less on the under surfaces of the metatarsal bones. 
 The plantar muscles are called adductors, while the dorsal 
 are spoken of as abductors. 
 
 The ADDUCTOR TERTII DIGITI, Fig. 256 (i), arises from the 
 inner side of the third metatarsal bone, and is inserted into the 
 inner side of the base of the first phalangeal bone of the 
 middle toe. Its tendon is also blended with the tendons of 
 the extensor muscles of the toes. 
 
 The ADDUCTOR QUARTI DIGITI, Fig. 256 (2), arises from 
 the inner side of the fourth metatarsal bone, and is inserted 
 
 50* 
 
594: 
 
 THE LOWER EXTREMITY. 
 
 into the inner side of the base of the first phalangeal bone of 
 the fourth toe, and also into the tendons of the extensor 
 muscles. 
 
 The ADDUCTOR MINIMI DIGITI, Fig. 256 ( 3 ), arises from the 
 inner side of the fifth metatarsal bone, and is inserted into the 
 first phalangeal bone of the little toe. This muscle is very fre- 
 quently inseparably connected with the flexor brevis minimi. 
 
 Fig. 255. 
 
 DORSAL INTEROSSET. 1. Abductor 
 interims secundi. 2. Abductor externus 
 secundi. 3. Abductor tertii. 4. Ab- 
 ductor quarti. 
 
 PLANTAR INTEROSSEI. 1. Adductor 
 tertii. 2. Adductor quarti. 3. Adductor 
 minimi digiti. 
 
 The dorsal or superior interosseous muscles are found on 
 the dorsum of the foot. They arise by two heads. They are 
 usually considered abductor muscles } the median line of the 
 foot, which corresponds to the axis of the second toe, being 
 taken as the line from which these muscles draw the toes. 
 
 The ABDUCTOR INTERNUS SECUNDI DIGITI, Fig. 255 (i), 
 arises from the outer side of the first metatarsal bone, and 
 from the inner side of the second, and is inserted into the inner 
 
LIGAMENTS OF THE KNEE, ANKLE, AND FOOT. 595 
 
 side of the base of the first phalangeal bone of the second 
 toe; like the plantar, it joins the tendons of the extensor 
 muscles. It draws the second to the great toe or from the 
 median line of the foot. 
 
 The ABDUCTOK EXTERNUS SECUNDI DIGITI, Fig. 255 (2), 
 arises by two heads from the opposite surfaces of the second 
 and third metatarsal bones, and is inserted into the outer side 
 of the base of the first phalangeal bone of the second toe. It 
 draws the second toe from the median line of the foot. 
 
 The ABDUCTOR DIGITI TERTII, Fig. 255 (3), arises from the 
 opposite surfaces of the third and fourth metatarsal bones, 
 and is inserted into the outer side of the first phalangeal bone 
 of the third toe. It' separates the third toe from the second. 
 
 The ABDUCTOR DIGITI QUARTI, Fig. 255 (4), arises by two 
 heads from the opposite surfaces of the fourth and fifth meta- 
 tarsal bones, and is inserted into the outer side of the base of 
 the first phalangeal bone of the fourth toe. It draws the 
 fourth from the third toe. 
 
 SECT. VII. DISSECTION OF THE LIGAMENTS OF THE KNEE, 
 ANKLE, AND FOOT. 
 
 The KNEE-JOINT is the largest of all the articulations. Prom 
 its liability to injuries and diseases of different kinds, its study 
 demands the earnest attention of every student. Before com- 
 mencing the dissection of it, he should, if possible, carefully 
 examine the bones which enter into its formation, or, at least, 
 as far as they enter into the mechanism of the joint; it is 
 better that they should be examined in an articulated skele- 
 ton, as the relative position of each prominent point can then 
 be observed and much better appreciated. He should also 
 carefully observe the prominences and depressions around the 
 joint when the limb is flexed, or extended, or placed in any 
 intermediate position, so that he may be able, in case of dis- 
 ease or injury, to detect any deviation in the general contour 
 of the knee from its natural appearance. 
 
 Three bones enter directly into the formation of the knee- 
 joint; they are the/emwr, the patella, and the tibia; the fibula 
 indirectly contributes to the formation of the joint, inasmuch 
 as it gives attachment to the inferior extremities of the ex- 
 
596 THE LOWER EXTREMITY. 
 
 ternal lateral ligaments, thus compensating for the want of 
 greater breadth in the upper extremity of the tibia to meet 
 the corresponding diameter of the femur. There is but one 
 articular surface on the femur, which may be divided into 
 three parts: a trochlear surface for the patella, and two orbicu- 
 lar surfaces for the glenoid cavities of the tibia ; the former is 
 placed in the middle anteriorly, being continuous laterally and 
 posteriorly with the latter, which are placed behind, one on 
 each side of the inter-condyloid notch. The glenoid cavities on 
 the tibia are entirely distinct from each other, being separated 
 by a prominence called the spine of the tibia, and two de- 
 pressions, one behind and the other before the spine; the in- 
 ter-glen oid space thus formed corresponds to the inter-condy- 
 loid notch; by means of this arrangement, the two strongest 
 ligaments in the joint, the crucial ligaments, are thrown into 
 the central part of the articulation, thus presenting a very 
 interesting feature in the mechanism of this joint. The whole 
 of the posterior surface of the patella is covered by articular 
 cartilage; in shape it is perfectly adapted to the trochlear 
 surface on the femur, whether the leg is flexed or extended ; 
 the femur moves on the patella, as the latter, owing to its liga- 
 ment being inelastic, is stationary whenever the quadriceps 
 extensor contracts. From the shape of the articular surfaces 
 just noticed, it will be seen that flexion and extension are the 
 principal movements for which they are adapted ; if the tibia 
 be fixed, as in standing on one leg, the femur may be slightly 
 rotated, the internal condyle turning on its axis in the corre- 
 sponding glenoid cavity, as if moving on a pivot. 
 
 In examining the parietes of the knee-joint, it is better to 
 divide them into six parts or regions, which require to be 
 studied separately. By doing this, the student will be able 
 to obtain a more satisfactory knowledge of the walls of this 
 articulation. These parts are situated, one in front, two on 
 each side, and one behind. 
 
 The anterior region contains, in the upper part of it, the 
 tendon of the quadriceps extensor muscle, Fig. 260 (2), in the 
 middle the patella (s), and in the lower part the ligamentum 
 patellae, and a considerable quantity of adipose substance (4). 
 There are two bursce mucosce in this region; one between the 
 patella and the integument, and the other between the liga- 
 mentum patellas and the tibia, just above its tubercle (G). 
 
 The lateral regions consist of an antero-lateral and a postero- 
 
LIGAMENTS OF THE KNEE-JOINT. 597 
 
 lateral on each side. The first of these might very appropri- 
 ately be called the aponeurotic regions. In the outer one the 
 parietes consist of the fascia lata, which is prolonged down- 
 wards over every part of the knee, in this as well as in the 
 other regions ; and beneath the fascia lata, of a thick fibrous 
 layer, which is expanded from the tendon of the vastus ex- 
 ternus, and, proceeding downwards, is inserted into the tibia 
 between its tubercle and the lower attachments of the external 
 lateral ligaments ; and, under this, of a layer of fibres which 
 arise from the outer border of the patella, and, passing trans- 
 versely outwards, are inserted into the outer surface of the 
 external condyle of the femur. The parietes in the inner 
 antero- lateral region are very nearly the same as in the one 
 just described; instead of the vastus externus, the vastus in- 
 ternus sends off a layer of vertical fibres, which pass down- 
 wards to be inserted into the tibia between its tubercle and 
 the internal lateral ligament; there is no difference in the 
 arrangement of the layer of transverse fibres; they are attached 
 to the inner border of the patella, and to the internal condyle 
 of the femur. The parietes of the joint in these regions are 
 interesting on account of its being in one or the other of them 
 that the cavity is entered by instruments, either in cases of 
 hydrops articuli, or of loose cartilages in the joint, requiring 
 an operation ; it is in these regions, also, that a bulging is first 
 observed, denoting the presence of water in the joint. 
 
 The parietes in the postero-lateral regions consist of the late- 
 ral ligaments. As these ligaments are unyielding, there are 
 generally depressions in hydrops articuli corresponding to 
 these regions. The tendons of the inner and outer hamstring 
 muscles also correspond very nearly to them. 
 
 In the posterior region the parietes are formed by the liga- 
 mentum posticum. This is very deep seated, having the con- 
 tents of the popliteal space placed between it and the external 
 surface. When the cavity of the joint is opened, it should be 
 studied in connection with these regions. 
 
 The ligaments of the knee-joint are divided into the external 
 and internal. The former can be exposed without cutting into 
 the cavity of the joint. By referring to the plates, the student 
 will have no difficulty in ascertaining the exact position of 
 each one. Their positions in the parietes of the joint have 
 already been noticed. They will now be examined more par- 
 ticularly with reference to their appearance and attachments. 
 
598 
 
 THE LOWER EXTREMITY. 
 
 The LIGAMENTUM PATELLA, Fig. 257 (3), may be regarded 
 as a continuation of the tendon of the quadriceps extensor 
 cruris ; so that, instead of arising from the patella, the latter 
 might be considered a sesamoid bone developed in the tendon 
 of the quadriceps muscle, of which the ligamentum patellae 
 would be the lower part. It is attached below to the tubercle 
 of the tibia, where it is considerably narrower than it is at its 
 attachment to the patella. It is about two inches in length. 
 By observing its white, shining appearance, the dissector will 
 have no difficulty in distinguishing it from the surrounding 
 parts. Whether it be considered a ligament or not, it serves 
 as the medium through which the above-mentioned muscle 
 acts on the leg. When the cavity of the joint has been opened 
 
 Fig. 257. 
 
 Fig. 258. 
 
 AN ANTERIOR VIEW OP THE 
 LIGAMENTS OP THE KNEE- 
 JOINT. 1. The tendon of the 
 quadriceps extensor muscle of 
 the leg. 2. The patella. 3. 
 The ligamentum patellae, near 
 its insertion. 4, 4. The syno- 
 vial membrane. 5. The inter- 
 nal lateral ligament. 6. The 
 long external lateral ligament. 
 7. The anterior superior tibio- 
 fibular ligament. 
 
 A POSTERIOR VIEW OF THE LIGAMENTS OF THE 
 KNEE-JOINT. 1. The fasciculus of the ligamentum 
 postieum Winslowii, which is derived from 2, the 
 tendon of the semi-membranosus muscle ; the latter 
 is cut short. 3. The process of the tendon which 
 spreads out in the fascia of the popliteus muscle. 
 4. The process which is sent inwards beneath the 
 internal lateral ligament. 5. The posterior part 
 of the internal lateral ligament. 6. The long ex- 
 ternal lateral ligament. 7. The short external 
 lateral ligament. 8. The tendon of the popliteus 
 muscle, surrounded by synovial membrane. 9. 
 The posterior superior tibio-fibular ligament. 
 
 and examined, the ligamentum patellae should be divided a 
 short distance below the patella, Fig. 259 (e), and its relations 
 to the cavity and to the tibia carefully studied ; a small bursa. 
 
LIGAMENTS OF THE KNEE-JOINT. 599 
 
 Fig. 259 (9), as was stated above, is -usually found separating 
 it, just above its insertion, from the tibia. 
 
 The EXTERNAL LONG AND SHORT LATERAL LIGAMENTS, 
 Fig. 258 (e , 7), are situated on the outer side of the joint. The 
 long external lateral ligament arises from the outer and back 
 part of the external condyle of the femur, close to the origin 
 of the popliteus, descends anterior to the tendon of the biceps, 
 and is inserted into the outer part of the head of the fibula. 
 The short external lateral ligament arises nearer the back part of 
 the external condyle, close to the origin of the tendon of the 
 external head of the gastrocnemius, passes downwards, and is 
 inserted into the posterior part of the head of the fibula. It 
 is smaller, shorter, and deeper seated than the long ligament. 
 It is connected to the semilunar cartilage, and sometimes ter- 
 minates in the coronary ligament. The inferior external 
 articular artery passes beneath both of these ligaments, and 
 they are separated from each other by a fasciculus of fibres 
 derived from the tendon of the biceps. 
 
 The INTERNAL LATERAL LIGAMENT, Fig. 258 (5), arises 
 from the inner and posterior surface of the internal condyle 
 of the femur, just below the insertion of the tendon of the 
 adductor magnus. It passes downwards beneath the tendons 
 of the sartorius, gracilis, and semi-tendinosus, from which it is 
 separated by a bursa, to be inserted into the inner part of the 
 head of the tibia. Its inner surface is in relation with the 
 semilunar cartilage and synovial membrane above, and the 
 inferior internal articular artery below. It is a broad, flat 
 ligament, being much broader, however, below than above. 
 
 The POSTERIOR LIGAMENT or LIGAMENTUM POSTICUM, 
 Fig. 258 (i), is composed of fibres which cross the articulation 
 behind in different directions; a large proportion of them, 
 however, have an oblique direction from the inner and poste- 
 rior part of the head of the tibia upwards and outwards to the 
 external condyle of the femur ; many of these fibres are con- 
 tinued from the tendon of the semi-membranosus, forming 
 what has been called the ligament of Winslow. It forms the 
 floor of the central part of the popliteal space. Anteriorly, 
 it is in relation with the semilunar cartilages, synovial mem- 
 brane, and the inter-condyloid notch. It is perforated by one 
 or more foramina, for the transmission of the middle articular 
 
600 THE LOWER EXTREMITY. 
 
 artery, or arteries when there is more than one. Tt is difficult 
 to make a clean dissection of this ligament, on account of the 
 fat usually found intermixed with its fibres. 
 
 To examine the interior of the knee-joint, a semilunar in- 
 cision should be made, with its concavity looking downwards, 
 through the tendon of the quadriceps extensor muscle and 
 the synovial membrane, about an inch above the patella, and 
 extending laterally to the lateral ligaments. Having made 
 the incision, and turned the patella downwards, with the leg 
 semi-flexed, a beautiful view of the interior of the joint is pre- 
 sented. The following parts should now be observed : - 
 
 First, the prolongation of the synovial membrane upwards 
 into a sort of pouch, between the tendon of the quadriceps 
 extensor and the anterior surface of the femur, Fig. 260 (&). 
 This should be carefully noted with reference to wounds 
 penetrating the cavity of the joint. The extension of the 
 synovial membrane upwards varies from an inch and a half 
 to three inches, the difference being caused by the position 
 of the leg as it regards flexion and extension ; when the leg 
 is flexed, it is not more than an inch and a half or two inches, 
 but is increased to two inches and a half or three inches when 
 the leg is extended. Hence, to determine whether a wound 
 situated two inches or a little more above the patella, has 
 penetrated the cavity of the joint or not, it is necessary to 
 ascertain the position of the leg at the time the wound was 
 inflicted. 
 
 Second, three folds of synovial membrane between the inter- 
 condyloid notch and the upper part of the ligamentum patellae 
 should be noticed. The middle one contains a few ligamentous 
 fibres, and has been named the ligamentum mucosum, Fig. 260 
 (10). The two lateral folds, which are frequently quite indis- 
 tinct, contain adipose substance ; they have been called, with- 
 out any good reason, the ligamenta alaria, Fig. 260 (9). The 
 use of the ligamentum mucosum is to hold the ligamenta alaria 
 in situ, and thus prevent them from being pinched by getting 
 between the articular surfaces of the bones. From the liga- 
 mentum mucosum, the synovial membrane is generally re- 
 flected backwards to the crucial ligaments, so as to form a 
 sort of septum dividing the posterior part of the cavity into 
 a right and left portion. 
 
 Dividing this fold, together with the ligamentum mucosum 
 and also the ligamentum patella, just below its upper attach- 
 
LIGAMENTS OF THE KNEE-JOINT. 601 
 
 ment, the space between the lining membrane of the joint 
 aad the ligamentum patella) should be examined. It will be 
 found to contain adipose substance, Fig. 260 (7), and the an- 
 astomosis between the external and internal inferior articular 
 arteries. It will be noticed that this space extends down- 
 wards between the head of the tibia. and the ligamentum 
 patellae, and that there is at the lower part of it a bursa, Fig. 
 259 (a), Fig. 260 (e), placed between the ligament and the 
 bone. This space should be studied with reference to wounds 
 penetrating the cavity of the joint, either directly through 
 the ligamentum patella or on either side of it. It will be 
 observed that the adipose substance in this space is pressed 
 backwards by the ligamentum patellae when the leg is flexed. 
 
 To examine the reflections of the synovial membrane in 
 the posterior lower part of the cavity, a vertical section of 
 the entire joint should be made, as represented in Fig. 260, 
 or one should be made of the femur and patella, down to the 
 space between the semilunar cartilages on the head of the 
 tibia. It will be found, when traced on the condyles, to ex- 
 tend upwards a short distance beyond their articular surfaces, 
 extending a little further up on the inner than on the outer 
 condyle. In the posterior part of the joint, it covers, on the 
 outer side, the anterior surface of the ligamentum posticum 
 and the outer head of the gastrocnemius, and also the tendon 
 of the popliteus, Fig. 258 (s), on which it is prolonged to the 
 superior articulation of the tibia and fibula, with the syno- 
 vial membrane of which it is sometimes connected, so as to 
 form a communication between that and the knee-joint. On 
 the inner side, it covers the anterior surface of the ligamentum 
 posticum and inner head of the gastrocnemius. In the central 
 part of the joint behind, it is reflected upon the sides of the 
 crucial ligaments, while opposite to these laterally, it covers 
 the lateral ligaments. In the lower part of the joint, it is 
 reflected over both the upper and lower surfaces of the semi- 
 lunar cartilages, and also over the articular surfaces on the 
 head of the tibia. Masses of adipose substance are observed 
 in different parts of the knee-joint; they are contained in 
 folds of the synovial membrane, and present different shapes ; 
 they have been called the synovial fringes ; they have also 
 been compared to the appendices epiploicse on the colon ; 
 they are even found in subjects which are greatly emaciated. 
 
 Having traced the synovial membrane in every part of the 
 51 
 
602 THE LOWER EXTREMITY. 
 
 joint, the lateral and posterior ligaments may be divided, or 
 removed, for the purpose of exposing the crucial ligaments; 
 it is better to divide them, just above the convex borders of 
 the semilunar cartilages, so that the connection between them 
 and these cartilages may be preserved. The synovial mem- 
 brane is easily detached from the crucial ligaments. These 
 ligaments are two in number; as their common name implies, 
 they cross each other; they are named separately the anterior 
 or external, and the posterior or internal. From their size and 
 arrangement, they contribute largely to the strength of the 
 knee-joint, in the central and posterior part of which they 
 are placed. 
 
 The ANTERIOR or EXTERNAL CRUCIAL LIGAMENT, Fig. 
 259 (2), arises from the tibia just in front of the spine, be- 
 tween the glenoid cavities, and passes upwards, outwards, and 
 backwards, to be inserted into the inner and posterior part of 
 the external condyle. 
 
 The POSTERIOR or INTERNAL CRUCIAL LIGAMENT, Fig. 
 259 (3), is somewhat larger, and more vertical in its direc- 
 tion than the anterior; it arises from the tibia just behind the 
 spine, and passes upwards and slightly forwards, to be inserted 
 into the outer part of the internal condyle. It is placed be- 
 tween the anterior crucial and the ligamentum posticum ; it 
 is best seen from behind, when the latter ligament has been 
 removed, while the anterior one is best seen from before. Each 
 ligament is connected at its origin with one of the semilunar 
 cartilages; the anterior with the anterior cornu of the in- 
 ternal, and the posterior with the posterior cornu of the 
 external semilunar cartilage. They limit the rotation of the 
 tibia inwards, but not outwards; and prevent too great ex- 
 tension of the leg on the thigh ; they also oppose abduction 
 or adduction of the leg. The crucial ligaments may now 
 be divided, and the semilunar fibre-cartilages with the liga- 
 ments which are connected to them for the purpose of keeping 
 them in situ, may now be examined. 
 
 There are two fibro-cartilages in the knee-joint, the IN- 
 TERNAL and EXTERNAL, called SEMILUNAR, from their shape ; 
 they are placed, one between each of the glenoid cavities and 
 its corresponding condyle. Each presents a thick convex 
 outer border, and a thin concave margin which looks towards 
 the centre of the joint, where a small portion of the articular 
 
LIGAMENTS OF THE KNEE-JOINT. 603 
 
 surface of the tibia is not covered with this fibro-cartilage. 
 Although these are interarticular fibro-cartilages, they differ 
 from those of other joints, as they do not form a septum 
 
 Fig. 259. 
 
 THE RIGHT KNEE-JOIXT LAID OPEN FROM THE FRONT, IN ORDER TO SHOAV THE IN- 
 TERNAL LIGAMENTS. 1. The cartilaginous surface of the lower extremity of the femur 
 with its two condyles; the figure 5 rests upon the external; the figure 3 upon the 
 internal condyle. 2. The anterior crucial ligament. 3. The posterior crucial liga- 
 ment. 4. The transverse ligament. 5. The attachment of the ligamentuin mucosum; 
 the rest has been removed. 6. The internal sernilunar fibro-cartilage. 7. The 
 external semilunar fibro-cartilage. 8. A part of the ligamentum patellae turned 
 down. 9. The bursa, situated between the ligamentum patella? and the head of the 
 tibia; it has been laid open. 10. The anterior superior tibio-fibular ligament. 
 11. The upper part of the interosseous membrane; the opening in this membrane 
 is for the passage of the anterior tibial vessels. 
 
 which divides the cavity into two compartments, but are 
 covered on both sides with the same synovial membrane. 
 
 The INTEENAL SEMILUNAK FiBno-CARTiLAGE,Fig.259 (e), 
 is placed on the internal glenoid cavity of the tibia, and is 
 applied by its superior surface to the internal condyle of the 
 femur. Its borders terminate in an anterior and a posterior 
 cornu, which are attached to the head of the tibia, one before 
 and the other behind the spine; the anterior cornu is con- 
 nected to the anterior crucial ligament. The internal lateral 
 and posterior ligaments are in apposition with its convex 
 border. The synovial membrane is continuous from one 
 surface to the other over its thin concave margin. 
 
 The EXTERNAL SEMILUNAK FLBRO-CARTILAGE, Fig. 259(7), 
 
604 THE LOWER EXTREMITY. 
 
 is placed between the external glenoid cavity of the tibia and 
 the external condyle of the femur; it is broader laterally 
 than the internal, but not so long, being more round, which 
 is owing to its attachments to the tibia being so close to each 
 other; like the internal, its upper surface is more concave 
 than the lower. Its cornua are attached to the tibia, one in 
 front and the other behind the spine, but between the attach- 
 ments of the cornua of the internal cartilage. The posterior 
 cornu is connected to the posterior crucial ligament. Its 
 attached, or thick, convex border is in apposition with the 
 posterior and the external lateral ligaments, and the tendon 
 of the popliteus muscle. 
 
 The semilunar nbro-cartilages are retained in situ by liga- 
 
 Fig. 260. 
 
 A LONGITUDINAL SECTION OF THE LEFT KNEE-JOINT, SHOWING THE REFLECTION 
 OF ITS SYNOVIAL MEMBRANE. 1. The cancellated structure of the lower part of the 
 femur. 2. The tendon of the extensor muscles of the leg. 3. The patella. 4. The 
 ligamentum patellse. 5. The cancellated structure of the head of the tibia. 6. A 
 bursa situated between the ligamentum patellae and the head of the tibia. 7. The 
 mass of fat projecting into the cavity of the joint below the patella. #* The syno- 
 vial membrane. 8. The pouch of synovial membrane which ascends between the 
 tendon of the extensor muscles of the leg, and the front of the lower extremity of 
 the femur. 9. One of the alar ligaments ; the other has been removed with the 
 opposite section. 10. The ligamentum mucosum left entire; the section being made 
 to its inner side. 11. The anterior or external crucial ligament. 12. The posterior 
 ligament. The scheme of the synovial membrane, which is here presented to the 
 student, is divested of all unnecessary complications. It may be traced from the 
 sacculus (at 8), along the inner surface of the patella; then over the adipose mass 
 (7), from which it throws off the mucous ligament (10); then over the head of the 
 tibia, forming a sheath to the crucial ligaments; then upwards along the posterior 
 ligament and condylea of the foinur to the sacculus, whence ita examination com- 
 menced. 
 
LIGAMENTS OF TIBIO-FIBULAR ARTICULATION. 605 
 
 mentous fibres, whicfy connect the convex border of each to 
 the corresponding portion of the parietes of the joint ; these 
 fibres constitute the coronary ligaments, there being one for 
 each of the fibro-cartilages. A fasciculus of fibres extends 
 from one cartilage to the other in front, and assists in pre- 
 venting them from being forced outwards; they form the 
 transverse ligament, Fig. 259 (4). The cornua consist almost 
 wholly of fibres which have been, where they are attached to 
 the bone, named the oblique ligaments. 
 
 It will be observed that only two of the internal ligaments 
 of this joint are intended to connect the femur to the tibia, 
 and to contribute directly to the strength of the articulation; 
 while the others are connected with the synovial mem- 
 brane and the fibro-cartilages; the latter may, at a casual 
 glance, appear to be unimportant, but when properly con- 
 sidered, they will be found to be essential to the perfection of 
 the joint. If, for instance, the ligamenta alaria are necessary 
 parts of the joint, then the ligamentum mucosum is requisite 
 to keep them in their proper place. The same is true of the 
 semilunar fibro-cartilages and the ligamentous fibres pro- 
 vided for keeping them in situ. 
 
 Having completed the dissection of the knee-joint, the 
 superior tilio-fibular articulation may be examined next. It 
 is formed by a small oval articular facet on the outer and 
 posterior part of the head of the tibia, and a corresponding 
 one on the head of the fibula ; both of these facets are covered 
 with articular cartilage and with synovial membrane, which 
 lines the parietes of the joint, forming a sac which sometimes 
 communicates with the cavity of the knee-joint. The fact of 
 a communication sometimes existing between this articula- 
 tion and the knee-joint, should be recollected in a case of dis- 
 articulation of the head of the fibula. Although ligamentous 
 fibres surround the articulation, so as to form an imperfect 
 capsular ligament, they may be described as forming an 
 anterior and & posterior ligament. 
 
 The ANTERIOR SUPERIOR TIBIO-FIBULAR LIGAMENT, Fig. 
 259 (i o), consists of a broad, flat fasciculus, which arises from 
 the anterior part of the head of the fibula, and passes ob- 
 liquely upwards and forwards, to be inserted into the ante- 
 rior and outer part of the tibia. 
 
 The POSTERIOR SUPERIOR TIBIO-FIBULAR LIGAMENT, 
 
 51* 
 
G06 
 
 THE LOWER EXTREMITY. 
 
 258 (9), is not so large as the anterior It arises from the 
 posterior part of the head of the fibula, and passes upwards 
 and backwards, to be inserted into the outer and posterior 
 part of the head of the tibia. The mobility allowed by this 
 articulation is very limited ; the head of the fibula may move 
 slightly backwards or forwards, or separate a very little from 
 the tibia. 
 
 The IKTEKOSSEOUS LIGAMENT or MEMBRANE, Fig. 261 (2), 
 which connects the shafts of the tibia and 
 Fig. 261. fibula, forms a septum between, or a floor for, 
 the anterior and posterior interosseous fossae. 
 It corresponds to the one between the radius 
 and ulna of the forearm. It is composed 
 principally of fibres which pass obliquely 
 downwards and outwards, from the outer 
 angle of the tibia to the inner part of the 
 fibula; a few fibres will be observed crossing 
 these. An opening is observed in the upper 
 part of it for the passage of the anterior tibial 
 vessels ; and another at the lower part, or 
 about an inch above the inferior tibio-fibular 
 articulation, for the transmission of the an- 
 terior division of the peroneal artery and 
 its venaa comites. Both of its surfaces, as 
 has been observed, are occupied by the 
 origins of muscles. This ligament is some- 
 times called the great or superior interosse- 
 ous ligament, to distinguish it from the small 
 or inferior interosseous ligament which con- 
 nects the lower extremities of the bones to- 
 gether. 
 
 The inferior tibio-fibular articulation is 
 formed by a vertical, concave, rough surface 
 on the outer part of the lower end of the 
 tibia, into which the lower end of the fibula 
 is received. Instead of having articular 
 cartilage, covered by synovial membrane, as 
 
 A PART OF THE FEMUR, THE PATELLA, THE BONES OP THE LEG, AND A RANGE OP 
 THOSE OF THE FOOT OF THE LEFT SIDE ARE VIEWED IN FRONT. Some ligaments of 
 
 the knee-joint are distinguishable. 1. Superior anterior tibio-fibular ligament. 2. 
 Interosseous membrane. 3. Inferior anterior tibio-fibular ligament. 4. Deltoid 
 of ankle-joint. 6. Middle division of external lateral j and 6, anterior division of 
 same. 7. Anterior ligament of ankle-joint. 
 
LIGAMENTS OF TIBIO-FIBULAR ARTICULATION. 607 
 
 in the superior articulation, the articular surfaces here are 
 occupied principally by ligamentous fibres, which form the 
 small or inferior interosseous ligament. Besides this ligament, 
 they are connected by an anterior, a posterior, and a transverse 
 ligament. 
 
 The ANTERIOR INFERIOR TIBIO-FIBULAR LIGAMENT, Fig. 
 
 261 (3), arises from the outer part of the lower end of the fibula, 
 passes upwards and inwards, spreading out so as to become 
 quite broad, and is inserted into the outer and anterior part 
 of the lower end of the tibia. It is composed of shining, 
 parallel fibres which extend below the articular surfaces, so 
 as to increase the depth of the cavity into which the astra- 
 galus is received. 
 
 The POSTERIOR INFERIOR TIBIO-FIBULAR LIGAMENT, Fig. 
 
 262 (2), consists of a fasciculus of fibres which arises from the 
 posterior and lower part of the fibula, and passes obliquely 
 upwards and inwards, to be inserted into the posterior and 
 lower part of the tibia. It is not so large as the preceding 
 ligament. 
 
 The TRANSVERSE TIBIO-FIBULAR LIGAMENT, Fig. 262 (s), 
 arises from the fibula, below the origin of the posterior liga- 
 ment, and, passing nearly transversely in- 
 wards, is inserted into the posterior part of Fig. 262. 
 the internal malleolus. It increases the 
 depth of the cavity formed by the tibia and 
 fibula for the reception of the astragalus. 
 
 The SMALL or INFERIOR INTEROSSEOUS 
 LIGAMENT consists of fibres, intermixed with 
 some adipose substance, which pass from 
 the articular surface of one bone directly 
 to that of the other. It is concealed by 
 the anterior and posterior ligaments, which 
 must be divided in order to bring it into 
 view, both from behind and before. It 
 adds greatly to the strength of this articula- 
 
 A POSTERIOR VIEW OF THE LIGAMENTS OF THE ANKLE-JOINT. 1. The lower part 
 of the interosseous membrane. 2. The posterior inferior tibio-fibular ligament. 3. 
 The transverse tibio-fibular ligament. 4. The internal lateral ligament. 5. The 
 posterior fasciculus of the external lateral ligament. 6. The middle fasciculus of 
 the external lateral ligament. 7. The synovial membrane of the ankle-joint. 8. 
 The 03 calcis. 
 
608 THE LOWER EXTREMITY. 
 
 tion, which, is probably stronger than if both bones were 
 connected at their lower extremities by osseous matter, so as 
 to form but a single piece. Articular cartilage covered with 
 synovial membrane, extends a very short distance upwards 
 between these bones. 
 
 The tibio-tarsal articulation, or ankle-joint, is formed by the 
 tibia and fibula above and on the sides, and the astragalus 
 below and in the centre ; it belongs to the class of gingly- 
 moid articulations. The tibia presents a horizontal, concave 
 surface with an antero-posterior ridge, and also a vertical 
 surface on the outer side of the internal rnalleolus, while the 
 fibula also furnishes a vertical surface on the inner side of 
 the external malleolus. The astragalus presents two vertical 
 surfaces, one for each of the malleoli, and another which is 
 concave transversely, and convex antero-posteriorly. These 
 surfaces are covered with articular cartilage and synovial 
 membrane. They allow of flexion and extension, and con- 
 siderable lateral movement. The ligaments of this joint con- 
 sist of an internal and an external lateral, and an anterior and 
 a posterior ligament. These ligaments, taken together, form a 
 sort of a capsular ligament, with the fibres accumulated 
 principally on the sides, constituting the lateral ligaments. 
 
 The EXTERNAL LATERAL LIGAMENT, Fig. 264 (e, 7, s), 
 connects the fibula with the astragalus and os calcis. It con- 
 sists of three distinct fasciculi, which radiate from the exter- 
 nal malleolus. The anterior passes forwards and downwards, 
 to be inserted into the anterior and outer part of the astraga- 
 lus; it is broader at its insertion than at its origin, and it is 
 shorter than the other two. The posterior passes backwards 
 and slightly downwards, to be inserted into the inner and 
 posterior part of the astragalus ; it is composed of parallel 
 fibres arranged in several layers, being the strongest of the 
 three fasciculi; the transverse tibio-fibular ligament is placed 
 just above it. The middle fasciculus arises from the lower 
 extremity of the external malleolus, between the origins of 
 the other two, and passes downwards and a little backwards, 
 to be inserted into the outer and middle part of the os calcis ; 
 the tendons of the long and short peronei muscles pass 
 over it. 
 
 The INTERNAL LATERAL or DELTOID LIGAMENT, Fig. 263 
 (e), consists of a superficial and a deep layer. The former 
 
LIGAMENTS OF THE ANKLE-JOINT 1 . 
 
 609 
 
 arises narrow from the inner and lower part of the internal 
 malleolus, and, spreading out, passes downwards, some of its 
 fibres being directed forwards, to be inserted into the os calcis 
 
 Fig. 263. 
 
 Fig. 264. 
 
 AN INTERNAL VIEW OP THE ANKLE- 
 JOINT RIGHT LEG. 1. The internal 
 malleolus of the tibia. 2, 2. Part of the 
 astragalus ; the rest is concealed by the 
 ligaments. 3. The os calcis. 4. The 
 scaphoid bone. 5. The internal cunei- 
 form bone. 6. The internal lateral or 
 deltoid ligament. 7. The anterior liga- 
 ment. 8. The tendo-Achillis; a small 
 bursais seen interposed between the ten- 
 don and the tuberosity of the os calcis. 
 
 AN EXTERNAL VIEW OP THE ANKLE- 
 JOINT RIGHT LEG. 1. The tibia. 2. 
 The external malleolus of the fibula. 
 3, 3. The astragalus. 4. The os calcis. 
 5. The cuboid bone. 6. The anterior 
 fasciculus of the external lateral liga- 
 ment attached to the astragalus. 7. Its 
 middle fasciculus attached to the os 
 calcis. 8. Its posterior fasciculus at- 
 tached to the astragalus. 9. The ante- 
 rior ligament of the ankle-joint. 
 
 and scaphoides. The latter arises immediately below the for- 
 mer, and is inserted into the astragalus. The tendons of the 
 long flexors of the toes and the tibialis posticus pass over 
 and partly conceal the lower and posterior part of this liga- 
 ment. 
 
 The ANTERIOR LIGAMENT, Fig. 263 (7), is broad but very, 
 thin; it arises from the lower and anterior part of the tibia, 
 and passes downwards and forwards to be inserted into the 
 astragalus. It is covered by the tendons of the muscles 
 which pass down in front of the ankle-joint. Some care is 
 requisite to preserve the fibres which compose this ligament. 
 
 A posterior ligament of the ankle-joint can hardly be said 
 to exist; its place is mainly, if not wholly, supplied by the 
 transverse tibio-fibular ligament and the posterior fasciculus 
 of the external lateral ligament. A good deal of adipose sub- 
 stance is found outside of the synovial membrane, both in 
 
610 THE LOWER EXTREMITY. 
 
 front of, and behind, the ankle-joint ; and, in removing it, the 
 student must be careful, or he will cut through the synovial 
 membrane, Fig. 262 (7), which is quite loose in these places, 
 especially in front, and expose the interior of the joint, Fig. 
 265 (9), before he desires to do so. 
 
 Perhaps no joint in the body is more liable to injury 
 than the ankle-joint, hence the importance of a thorough 
 knowledge of it to the student. It should be studied with 
 reference to luxations, fractures, and sprains. The mal- 
 leoli form prominent points, which can always be distinctly 
 seen and felt in the living subject. Their position in relation 
 to the other parts should be carefully noted, as they will be im- 
 portant guides in determining whether, in cases of injury or 
 disease, displacement of any part or parts has occurred, and, if 
 so, its character and extent, and also whether in the treatment 
 the parts displaced have been restored to their proper place. 
 
 The tarsal ligaments, like those of the carpus, are nume- 
 rous ; and while it is scarcely expected that the student will 
 have the time to become familiar with all, he should not 
 neglect to acquire a thorough knowledge of some of them. 
 A knowledge of the tarsal and the tarso-metatarsal articula- 
 tions is indispensable to any one who shall have occasion to 
 disarticulate the metatarsus, as in Hey's operation, or a por- 
 tion of the tarsus, as in Chopart's operation. As every phy- 
 sician is liable to have cases of inflammation of these joints 
 and its sequels, or of injuries not requiring, as a dernier 
 resort, or at least not immediately, amputation of a portion 
 of the foot, every student should avail himself of the oppor- 
 tunities afforded him in the dissecting-room to carefully exa- 
 mine and study the structure of the foot. Although it may 
 be the last part of the limb to be dissected, it is none the less 
 important. After dissecting the muscles, vessels, and nerves 
 of the whole, or any part of it, he should keep it wet until 
 he has time to examine all the articulations, which he can 
 easily do with the aid of his book and plates. 
 
 Having severed the ligaments which connect the tibia and 
 fibula with the tarsus, and dissected off all the soft parts 
 which cover the bones and ligaments of the foot, the liga- 
 mentous connections of the tarsus may be examined first. 
 Of these, the connections of the astragalus are, from its posi- 
 tion, its function, and liability to displacement, perhaps, the 
 
LIGAMENTS OF THE TARSUS. 611 
 
 most important. It is connected to the os calcis by three 
 ligaments, the interosseous, the posterior, and the external. 
 
 Fig. 265. 
 
 A VERTICAL SECTION OP THE ANKLE-JOINT AND FOOT OF THE RIGHT SIDE. 1. 
 The tibia. 2. The astragalus. 3. Os calcis. 4. The scaphoides. 5. The cunei- 
 forme internum. 6. The metatarsal bone of the great toe. 7. The first phalangeal 
 bone of the great toe. 8. The second phalangeal bone of the great toe. 9. The 
 articular cavity between the tibia and astragalus, "with its articular adipose sub- 
 stance. 10. The synovial capsule between the astragalus and os calcis. 11. The 
 calcaneo-astragaloid interosseous ligament. 12. The synovial capsule between the 
 astragalus and scaphoides. 13. The calcaneo-scaphoid ligament. 14. The calca- 
 neo-cuboid ligament. 15. The synovial capsule between the scaphoides and cunei- 
 forme internum. 16. The synovial capsule between the cuneiforme internum and 
 the first tnetatarsal bone. 17. The rnetatarso-phalangeal articulation of the great 
 toe, with the sesamoid bones below. 18. The phalangeal articulation of the great toe. 
 
 The INTEROSSEOUS LIGAMENT, Fig. 265 (i i), is placed in 
 a canal formed by a transverse groove on the under surface 
 of the astragalus, and a corresponding one on the upper sur- 
 face of the os calcis. It is a short, but very strong ligament, 
 forming the principal ligamentous connection between these 
 bones. Its fibres have more or less adipose substance inter- 
 mixed with them. To obtain a good view of this ligament, 
 a vertical section of the astragalus and os calcis should be 
 made, so as to divide the ligament in an antero-posterior di- 
 rection. These bones articulate with each other by mutual 
 reception ; the astragalus presents two articular surfaces ; a 
 concave one placed behind the groove, and a convex one 
 anterior to the groove, while the os calcis presents two cor- 
 responding articular facets. The articulation, posterior to 
 the groove, has a distinct synovial capsule, Fig. 265 (i o), while 
 the synovial capsule (12) of the articulation in front of the 
 
612 
 
 THE LOWER EXTREMITY. 
 
 groove is prolonged into the articulation formed by the 
 astragalus and the scaphoides. 
 
 The POSTERIOR LIGAMENT extends from the posterior part 
 of the astragalus to the upper part of the os calcis. 
 
 The EXTERNAL LATERAL LIGAMENT arises from the outer 
 and under surface of the astragalus, and passes downwards 
 beneath the middle fasciculus of the external lateral ligament, 
 to be inserted into the outer part of the os calcis. The 
 sheaths of the tendons of the long muscles which pass along 
 the inner side of the os calcis, supply the place of an internal 
 ligament. 
 
 The astragalus is connected to the scaphoides by the 
 astragalo-scaphoid ligament. To understand properly the 
 articulation of the astragalus with the scaphoid bone the 
 external and inferior calcaneo-scaphoid 
 Fig. 266. ligaments should be considered. 
 
 The ASTRAGALO-SCAPHOID LlGAMENT 
 
 arises from the anterior and upper part of 
 the astragalus, and passes forwards to be 
 inserted into the upper surface of the 
 scaphoid bone; it consists of a broad band 
 of parallel fibres which cover in the articu- 
 lation on the dorsum of the foot. It is 
 covered by the tendons of the extensor 
 muscles of the toes, and also by that of the 
 tibialis anticus. 
 
 The articulation of the astragalus with 
 the scaphoid bone belongs to the class of 
 enarthrodial joints, and is similar to that 
 formed by the os magnum and the first 
 row of bones in the carpus. It allows of 
 a much greater degree of mobility than 
 any other articulation in the tarsus, being 
 a ball and socket joint. The cavity into 
 
 THE LIGAMENTS OF THE SOLE OP THE LEFT FOOT. 1. The os calcis. 2. The 
 astragalus. 3. The tuberosity of the scaphoid bone. 4. The long calcaneo-cuboid 
 ligament. 5. Part of the short calcaneo-cuboid ligament. 6. The calcaneo-sca- 
 phoid ligament. 7. The plantar tarsal ligaments. 8, 8. The tendon of the pero- 
 neus longus muscle. 9, 9. Plantar tarso-metatarsal ligaments. 10. Glenoid liga- 
 ment of the metatarso-phalangeal articulation of the great toe ; similar ligaments 
 are seen upon the other toes. 11, 11, 11. Lateral ligaments of the metatarso- 
 phalangeal articulations. 12. Transverse ligament. 13. The lateral ligaments of 
 the phalangeal bones of the great toe ; similar ligaments are seen upon the other 
 toes. 
 
LIGAMENTS OF THE TARSUS. 613 
 
 wliicli the head of the astragalus is received is formed partly 
 by the inferior calcaneo-scaphoid ligament, which not only 
 supports the head of the astragalus, but assists in keeping 
 it applied to the glenoid cavity of the scaphoid bone. The 
 synovial membrane, Fig. 265 (12), of this joint is, as was be- 
 fore stated, continuous with the one in the anterior articu- 
 lation of the astragalus and os calcis. 
 
 The os calcis is connected to the scaphoid and cuboid 
 bones by several ligaments ; with the cuboid it is connected 
 by a superior, an inferior, and an inter osseous ligament, and 
 with the scaphoid bone by two, the external calcaneo-scaphoid, 
 and the inferior calcaneo-scaphoid ligament. 
 
 The SUPERIOR CALCANEO-CUBOID LIGAMENT arises from 
 the anterior and superior part of the os calcis, and passes for- 
 wards to be inserted into the superior and posterior surface 
 of the cuboid bone. 
 
 The INFERIOR CALCANEO-CUBOID LIGAMENT consists of 
 two fasciculi, a long or superficial, Fig. 266 (4 ), and a short or 
 deep-seated fasciculus (s) . The former is also called the long 
 plantar ligament. They both arise from the under surface of 
 the os calcis, but have very different insertions. The long 
 fasciculus extends forwards, to be inserted, partly into the 
 cuboid bone, and partly into the bases of the fourth and fifth 
 metatarsal bones ; it passes over and binds to the bone, the 
 tendon of the peroneus longus muscle. The short or deep- 
 seated fasciculus is inserted into the under surface of the 
 cuboid bone, being covered by the long one below, and lying 
 next to the bone above. 
 
 The INTEROSSEOUS or INTERNAL CALCANEO-CUBOID LI- 
 GAMENT arises from the groove in the os calcis and passes for- 
 wards, to be inserted into the inner and posterior part of the 
 cuboid bone. It is quite a short, but a strong ligament. 
 
 The EXTERNAL CALCANEO-SCAPHOID LIGAMENT arises 
 from the os calcis close to the origin of the internal calcaneo- 
 cuboid, and from its deep situation at its origin might, as 
 well as that, be called an interosseous ligament. It is inserted 
 into the upper and outer part of the scaphoid bone. 
 
 The INFERIOR or PLANTAR CALCANEO-SCAPHOID LIGA- 
 MENT, Fig. 266 ( ), arises from the anterior and lower part of 
 the os calcis, and passes forwards to be inserted into the 
 52 
 
614 THE LOWER EXTREMITY. 
 
 under surface of the scaphoid bone. It is considerably larger 
 than the preceding ligament. Its upper surface is partly 
 covered by the synovial membrane of the astragalo-scaphoid 
 articulation, of which it may be regarded as forming a part. 
 
 From the dissection that has now been made, the student 
 will be able to see what ligaments must be lacerated, when 
 the astragalus is luxated, and also what ligaments must be 
 divided in Choparfs operation, in which the scaphoid and cu- 
 boid bones are disarticulated from the astragalus and os calcis. 
 He has also seen three of the four synovial membranes or sacs 
 which are found in the tarsus. Fig. 265(io, 12, is, IG). 
 
 The remaining five bones of the tarsus are connected by 
 dorsal, plantar, and interosseous ligaments. It is not necessary 
 to describe each one of these separately. With a little care 
 and patience, the student will have little or no difficulty in 
 finding them. 
 
 The SCAPHOID BONE is connected to the cuboid by a dor- 
 sal, an interosseous, and a plantar ligament, all of which have 
 a transverse direction. Sometimes there are one or two small 
 synovial membranes between these bones, which are held 
 very firmly together by their ligaments. 
 
 The SCAPHOID BONE is connected to the three cuneiform 
 bones by four dorsal ligaments; one for each, except the in- 
 ternal, which has two, one of which is placed on the inner 
 side of the articulation, and is called the internal scaphoideo- 
 cuneiform ligament; it is also connected by three plantar liga- 
 ments, the principal one of which connects it to the internal 
 cuneiform, and is blended with the tendon of the tibialis 
 posticus. The synovial membrane, Fig. 265 (i 5), between the 
 scaphoid and cuneiform bones, is continuous with those found 
 between the latter bones. 
 
 The CUBOID BONE is joined to the external cuneiform 
 bone by a dorsal, a plantar, and an interosseous ligament. 
 These ligaments have a transverse direction. The plantar 
 one is very small. 
 
 The CUNEIFORM BONES are connected to each other by 
 dorsal, plantar, and interosseous ligaments. Of these, the 
 interosseous are the strongest. The plantar are very small. 
 The fourth synovial membrane of the tarsus is common to 
 the articulations of the cuboid with the external cuneiform, 
 
LIGAMENTS OF THE METATARSUS. 615 
 
 to the scaphoid with the three cuneiform, and to the cuneiform 
 with each other. The same synovial membrane is also pro- 
 longed forwards between the cuneiform bones and the first, 
 second, and third metatarsal bones. Fig. 265 (i e). 
 
 The TARSO-METATARSAL ARTICULATION is formed by the 
 cuboid and the three cuneiform bones, and the five metatarsal 
 bones. The middle cuneiform bone is shorter than the other 
 two, and hence the second metatarsal bone projects backwards 
 between the internal and external cuneiform. In disarticu- 
 lating the metatarsus from the tarsus, as in Hey's operation, it 
 is important to recollect this arrangement. It will be seen that 
 the internal cuneiform articulates with the first and second 
 metatarsal, the second cuneiform with the second metatarsal, 
 and the third cuneiform with the second and third metatarsal, 
 while the cuboid is joined to the fourth and fifth metatarsal 
 bones. These articulations allow some degree of mobility, 
 especially when considerable force is used, as in jumping and 
 leaping. The same is true of the articulations between the 
 anterior five bones of the tarsus. Although the motion al- 
 lowed by any single one of these articulations is very little, in 
 the aggregate it amounts to considerable. 
 
 The tarsus is joined to the metatarsus by dorsal, plantar, and 
 interosseous ligaments. Each metatarsal bone, except the second, 
 is connected to the tarsal bone with which it articulates by a 
 dorsal ligament; the second is joined to each of the three 
 cuneiform bones by a dorsal ligament, and to each of the in- 
 ternal and middle by a plantar ligament. The articulation of 
 the first metatarsal bone is strengthened by fibres derived from 
 the insertion of the tendons of the tibialis anticus and peroneus 
 longus. The fourth and fifth metatarsal bones obtain their 
 plantar ligaments from fibres derived from the sheath of the 
 peroneus longus. The tendon of the peroneus brevis and 
 the external division of the plantar aponeurosis assist in 
 keeping the fifth metatarsal bone in its place. The inter- 
 osseous ligaments are placed between the bones which they 
 connect. 
 
 The METATARSAL BONES are connected together at their 
 tarsal extremities by three sets of ligaments, dorsal, interosseous, 
 and plantar. The interosseous are very strong, passing directly 
 from one bone to another. The dorsal and plantar ligaments 
 
616 THE LOWER EXTREMITY. 
 
 also have a transverse direction. At their phalangeal extre- 
 mities they are connected by a transverse ligament. Fig. 
 266(i,). 
 
 The METATARSAL BONES are connected to each of the 
 phalangeal bones by two lateral, and one glenoid ligament for 
 each articulation. Fig. 266 (10, 1 1). The tendons of the ex- 
 tensor muscles of the toes supply the place of the dorsal liga- 
 ments. The glenoid ligaments are dense, like fibro-cartilage. 
 There is one placed below each articulation, the edges of 
 which are continuous with the lateral ligaments, and also with 
 the sheath of the corresponding tendons of the common 
 flexor muscles of the toes. Each also assists in forming the 
 cavity for the reception of the head of the corresponding 
 metatarsal bone. The lateral ligaments are very strong; 
 each one, as well as the glenoid ligament, is connected with 
 the digital processes of the plantar aponeurosis. 
 
 The PHALANGEAL BONES are connected together by means 
 of one glenoid and two lateral ligaments. Fig. 266 (is), for 
 each joint. The glenoid ligament has the same arrangement 
 as in the preceding articulation, and the lateral ligaments 
 also have the same attachments and the same relations as in 
 that joint. As in the metatarso-phalangeal articulations, 
 there are no dorsal ligaments, the tendons of the extensor 
 muscles supplying their places. There is nothing connected 
 with the synovial membranes in these articulations that re- 
 quires any notice. 
 
INDEX. 
 
 ABDOMEN, 339 
 
 cavity of, 360 
 
 regions of, 360 
 Abdominal ring, external, 344, 350 
 
 internal, 354 
 Acini, 400, 402 
 Alimentary canal, 387 
 Annulus ovalis, 302 
 Anti-helix, 120 
 Anti-tragus, 120 
 Aorta, abdominal, 410 
 
 arch of, 318 
 
 descending, 315 
 Aortic opening of diaphragm, 419 
 
 of heart, 309 
 Aponeurosis, brachial, 249 
 
 costo-clavicular, 212 
 
 of forearm, 258 
 
 gluteal, 511 
 
 palatine, 150 
 
 pharyngeal, 205 
 
 temporal, 49 
 
 vertebral, 228 
 
 Apparatus ligamentosus colli, 532 
 Appendices epiploicae, 372 
 Appendix auriculae, 302, 307 
 
 vermiformis caeci, 371, 397 
 Aqueduct of Fallopius. 124 
 
 of Sylvius, 65 
 Aqueductus cochleae, 130 
 Aqueous humor, 110 
 Arachnoid membrane, of brain, 53 
 
 of spinal cord, 287 
 Arbor vitae cerebelli, 73 
 
 uterina, 487 
 Arch, of colon, 372 
 
 dorsal, 570 
 
 femoral, deep, 499 
 
 palmar, deep, 279 
 
 superficial, 274 
 
 plantar, 582 
 Arciform fibres, 75 
 Arm, superficial veins at bend, 248 
 ARTERIES, 
 
 ad cutem abdominis, 341, 490 
 
 52* 
 
 ARTERIES continued. 
 
 anastomotic of femoral, 550 
 
 of brachial, 253 
 aorta, 300 
 articular of knee, 
 
 external, inferior, 550 
 superior, 550 
 
 internal, inferior, 551 
 lower superior, 550 
 superior, 550 
 
 middle, 551 
 ascendens colli, 172 
 auricular, 122 
 
 posterior, 51, 184 
 axillary, 212, 215 
 basilar, 86 
 brachial, 252 
 brain, of the, 85 
 bronchial, 322 
 bulbar, 465 
 
 carotid, common, left, 192, 320 
 right, 192 
 
 internal, 184 
 
 carpal, ulnar, anterior, 264 
 posterior, 264 
 
 radial, 264 
 
 centralis retinae, 94, 100 
 cerebellar inferior, 87 
 
 superior, 87 
 cerebral, anterior, 85 
 
 middle, 85 
 
 posterior, 86 
 cervical, posterior, 175, 227 
 
 profound, 174, 233 
 
 transverse, 172 
 ciliary, 95, 104 
 circumflex ilii, external, 490 
 
 internal, 346, 358 
 
 of arm, anterior, 219, 239 
 posterior, 218, 222, 239 
 
 of thigh, external, 505 
 internal, 505, 543 
 coccygeal, 444 
 coeliac, 373, 375 
 colic, ileo-, 381 
 
018 
 
 INDEX. 
 
 ARTERIE s continued. 
 colic, left, 383 
 
 middle, 381 
 
 right, 381 
 comes nervi, ischiadici, 444, 516 
 
 phrenici, 294 
 
 communicating of brain, anterior, 
 85 
 
 of brain, posterior, 85 
 coronaria, dextra, 314 
 
 sinistra, 314 
 
 superioris, 378 
 corporis bulbosi, 429 
 
 cavernosi, 429 
 cremasteric, 358 
 cricoid, 183 
 
 cutaneous of abdomen, 341 
 cystic, 379, 404 
 deferential, 442 
 dental inferior, 113 
 
 superior, 115 
 digitales manus, 274 
 
 pedis, 588, 590 
 dorso-carpal, radial, 273 
 dorsalis pedis, 577 
 
 penis, 429 
 
 scapulae, 218, 222, 242 
 dorsal of tarsus, 579 
 epigastric, 348, 355, 358 
 
 superficial, 490 
 ethmoidal, 95 
 facial, 36, 50, 158, 176 
 femoral, 504 
 gastric, 378 
 gastrocnemial, 552 
 gastro-duodenal, 378 
 gastro-epiploic, left, 376 
 
 right, 379 
 gluteal, 444, 514 
 hemorrhoidal, inferior, 421, 457 
 
 middle, 443 
 
 superior, 383 
 hepatic, 373, 378 
 hypogastric, 439 
 humeral, transverse, 172, 227 
 iliac, common, 412 
 external, 412 
 internal, 439 
 ileo-colic, 381 
 
 -lumbar, 441 
 
 infra-orbital, 38, 115, 117 
 innominata, 168, 320 
 intercostal, 233, 329, 357 
 
 anterior, 294 
 
 superior, 174 
 interosseous, of arm, 264 
 
 anterior, 264, 267 
 
 posterior, 264, 271 
 intestinal, large, 381 
 
 small, 380 
 
 ARTERIE s continued. 
 ischiatic, 444 
 lachrymal, 94 
 laryngeal, 183 
 lingual, 181 
 lumbar, 233, 358, 410 
 magna pollicis, manus, 279 
 
 pedis, 590 
 malleolar, external, 577 
 
 internal, 577 
 
 mammary,internal, 172,293,348,357 
 masseteric, 111 
 maxillary, internal, 112 
 mediastinal, 294 
 meningeal, anterior, 90, 114 
 
 middle, 90, 113 
 
 parva, 90 
 
 posterior, 90 
 mesenteric, inferior, 383 
 
 superior, 379 
 metacarpal, ulnar, 264 
 metatarsal, 579 
 musculo-phrenic, 294 
 nasal, 96 
 of Nebauer, 166 
 obturator, 412, 441 
 occipital, 51, 183, 232 
 oesophageal, 329 
 ophthalmic, 50, 94 
 ovarian, 443 
 palpebral, 95 
 pancreatic, 376 
 
 pancreatico-duodenal, 378, 380 
 perforantes, femoralis, 506, 543 
 
 of foot, 588, 589 
 perineal, superficial, 462 
 
 transverse, 462 
 peroneal, 561 
 
 anterior, 562 
 
 posterior, 562 
 pharyngeal, ascending, 183 
 
 inferior, 183 
 phrenic, 410 
 plantar, external, 588 
 
 internal, 588 
 popliteal, 549 
 princeps cervicis, 183, 232 
 profunda, femoris, 505 
 
 inferior of arm, 253 
 
 superior of arm, 253 
 pterygoid, 114 
 pubic, 358 
 
 pudic, external, superior, 490 
 inferior, 505 
 internal, 444, 466, 516 
 pulmonary, 300, 306, 321, 328 
 pyloric, superior, 373 
 radial, 262, 273, 279 
 radialis indicis, 279 
 ranine, 154 
 
INDEX. 
 
 619 
 
 ARTERIES continued. 
 recurrent, radial, 262 
 
 tibial, anterior, 577 
 internal, 561 
 
 ulnar, anterior, 264 
 posterior, 264 
 renal, 385 
 sacral, middle, 411, 439 
 
 lateral, 443 
 scapular posterior, 156 
 sciatic, 444, 516 
 sigmoid, 383 
 spermatic, 384, 435 
 spinal, anterior, 288 
 
 posterior, 288 
 of the spinal cord, 288 
 splenic, 376 
 
 subclavian, 170, 192, 330 
 sublingual, 154 
 submental, 159, 176 
 subscapular, 218 
 superficial volae, 262 
 supra-orbital, 50, 94 
 supra-renal, 385 
 
 supra-scapular, 172, 227, 240, 242 
 tarsal, 579 
 temporal, 50 
 
 anterior, 50 
 
 deep, 110 
 
 middle, 50 
 
 posterior, 50 
 thoracica-acromial, 211, 212 
 
 -axillaris, 218 
 
 inferior, 214 
 
 superior, 211, 212 
 tibial anterior, 576 
 
 posterior, 560 
 thyroid, axis, 170 
 
 inferior, 170, 171 
 
 middle, 166 
 
 superior, 183 
 transverse facial, 32 
 tympanic, 114, 131 
 ulnar, 263 
 umbilical, 439 
 uterine, 443 
 vaginal, 443 
 vasa brevia, 376 
 vertebral, 86, 173, 233 
 vesical, 442 
 ARTICULATIONS, 
 
 sacro-vertebral, 535 
 sacro-coccygeal, 535 
 sacro-iliac, 536 
 tarsal, 610 
 tarso-metatarsal, 615 
 temporo-maxillary, 115 
 tibio-fibular, inferior, 606 
 
 superior, 605 
 tibio-tarsal, 608 
 
 ARTICULATIONS continued. 
 metatarso-phalangeal, 616 
 metatarsal, 615 
 phalangeal of foot, 616 
 
 of hand, 285 
 Arytenoid cartilages, 195 
 Auricle of ear, 120 
 
 of heart, left, 300, 301, 307 
 right, 300, 301, 302 
 Auricula of heart, 302 
 Auriculo- ventricular orifice, left, 308 
 
 right, 305 
 Axillary artery, surgical relations of, 
 
 213, 216 
 Axillary region, 207 
 
 Back, nerves of, 224 
 
 arteries of, 224 
 Bladder, female, 482 
 
 male, 421, 436 
 Bone, hyoid, 193 
 
 turbinated, inferior, 137 
 middle, 138 
 superior, 138 
 Brain, base of, 76 
 
 membranes of, 52 
 
 dissection of, 52 
 Bronchial tubes, 326 
 Bronchi, 322 
 Brunner's glands, 394 
 Bulb of corpus spongiosum, 427, 438 
 Bulbi vestibuli, 480 
 Bulbous part of the urethra, 426 
 Bursaa at wrist, 276 
 
 Caecum, 371 
 
 Calamus scriptorius, 68 
 
 Calices, 407 
 
 Canal, of Bichat, 80 
 
 of Cloquet, 109 
 
 of the Epididymis, 433 
 
 of Fontana, 104 
 
 inguinal, 352 
 
 of Nuck, 483 
 
 of Petit, 109 
 Canals, portal, 401 
 Canaliculi lachrymales, 45 
 Capsule of Glisson, 400 
 Capsules, supra-renal, 409 
 Caput gallinaginis, 425 
 Cartilage, cricoid, 194 
 
 thyroid, 194 
 
 Cartilages, arytenoid, 195 
 appendices, 196 
 
 costal, 334 
 
 inter-articular, of the clavicle, 243, 
 335 
 
 inter-articular, of the jaw, 116 
 of knee, 602 
 
 of nose, 134 
 
620 
 
 INDEX. 
 
 Cartilages of nose 
 
 columna, 134 
 lateral inferior, 135 
 
 superior, 135 
 septal, 134 
 sesamoid, 136 
 semilunar, 602 
 tarsal, 43 
 
 Caruncula lachrymalis, 44 
 Carunculae myrti formes, 478 
 Cauda equina, 289 
 Cerebellum, 69, 73 
 Cerebrum, 56 
 
 lobes of, 80 
 
 Chamber of eye, anterior, 105 
 posterior, 104 
 Cheeks, 144 
 
 Chordae, tendinese, 305, 308 
 vocales, 198 
 Willisii, 55 
 Choroid coat, 104 
 plexus, 61, 69 
 Ciliary ligament, 103 
 
 processes, 107 
 Circle of Willis, 85, 87 
 Clitoris, 477 
 Cochlea, 128 
 Coeliac axis, 376 
 Colon, ascending, 371 
 descending, 372 
 transverse, 372 
 Columnse carneae, 304, 308 
 Commissures of brain, anterior, 64 
 longitudinal superior, 57 
 middle, 64 
 posterior, 64 
 of cord, gray, 290 
 
 white, 290 
 Concha, 120 
 Coni vasculosi, 433 
 Conjunctiva, 44, 102 
 Conus arteriosus, 305 
 Conjoined tendon, 345 
 Cord, spermatic, 434 
 Cornea, 102 
 
 Cornua ventriculorum, 59, 61 
 Corpora Arantii, 306, 309 
 cavernosa penis, 427 
 
 clitoridis, 477 
 geniculata, 63 
 mamrnillaria, 78 
 olivaria, 74 
 pyramidalia, 74 
 pyramidalia posterior, 75 
 restiformia, 75 
 Corpus callosum, 57 
 
 arteries of, 85 
 
 peduncles of, 79 
 dentatum, 73 
 fimbriatum, 484 
 
 Corpus fimbriatum 
 
 of the brain, 62 
 
 Highmorianum, 432 
 
 luteum, 488 
 
 rhomboideum, 73 
 
 spongiosum, 427 
 
 striatum, 59 
 
 Cowper's glands, 426, 428, 466 
 Cranium, soft parts on upper part of, 47 
 
 cellulo-adipose layer on, 47 
 Cricoid cartilage, 194 
 Corpuscles of Malpighi, 408 
 Corona glandis, 427 
 Crico-thyroid membrane, 198 
 Crura cerebelli, 68 
 
 cerebri, 77 
 Crural canal, 497 
 
 ring, 497 
 
 Crystalline lens, 109 
 Cupola of ear, 130 
 Culs-de-sac of stomach, 387 
 Cuneiform bodies, 197 
 Cystic duct, 403 
 
 Dartos, 430 
 Diaphragm, 417 
 Duct, cystic, 403 
 
 hepatic, 401, 403 
 
 lymphatic right, 192, 330 
 
 pancreatic, 374, 393, 404 
 
 of Steno, 32 
 
 thoracic, left, 191, 315, 329 
 
 of Wharton, 177, 179 
 Ducts, of Bellini, 408 
 
 of Kivinus, 181 
 Ductus, ad nasum, 46, 137 
 
 arteriosus, 321 
 
 cominunis choledochus, 373, 393, 
 493 
 
 ejaculatorius, 434 
 
 venosus, 400 
 
 vesiculse seminales, 434 
 Duodenum, 370, 392 
 Dura mater of cerebrum, 53, 87 
 arteries of, 90 
 nerves of, 90 
 
 of spinal cord, 286 
 
 Ear, external, 120 
 
 internal, 127 
 
 middle, 123 
 
 Eminentia pyramidalis, 128 
 Endocardium, 310 
 Endolymph, 130 
 Epididymis, 431 
 Epiglottic gland, 197 
 Epiglottis, 196 
 Eustachian tube, 124, 139, 149, 152 
 
 valve, 303 
 
INDEX. 
 
 621 
 
 Eye, 
 
 appendages of, outside of orbit, 40 
 
 within orbit, 91 
 ball, 99 
 brows, 40 
 lashes, 40 
 pupil of, 105 
 
 Pace, 29 
 
 Falciform process, 494 
 Fallopian tubes, 484 
 Falx, cerebelli, 88 
 
 cerebri, 55 
 Fascia, of abdomen, superficial, 340, 350 
 
 anal, 460 
 
 cervical, deep, 170 
 superficial, 161 
 
 conjoined, of pelvic and deep pe- 
 rineal, 471 
 
 cremasteric, 430 
 
 cribriform, 493 
 
 iliac, 415 
 
 infra-spinous, 241 
 
 infundibuliform, 355 
 
 inter-columnar, 350, 430 
 
 lata, 493, 541 
 
 intermuscular septa of, 502 
 
 of leg, deep anterior, 571 
 
 posterior, 556, 559, 566 
 
 levator, 460 
 
 lumborum, 234 
 
 masseteric, 32 
 
 obturator, 460 
 
 palmar, 274 
 
 parotid, 31 
 
 pectoral, deep, 209 
 
 pelvic, 460, 472 
 
 perineal, deep, 462, 465, 467, 470 
 superficial, 456, 462 
 
 perineo-pelvic, 474 
 
 plantar, 584 
 
 propria, 495 
 
 recto-vesical, 460, 473 
 
 of Scarpa, 341 
 
 Spermatic, 350, 430 
 
 supra-spinous, 239 
 
 transversalis, 354, 430 
 
 of Tyrrell, 473 
 Fauces, 146 
 Femoral hernia, 497 
 
 ring, 497 
 Fenestra, ovalis, 124 
 
 rotunda, 124 
 
 Fibro-cartilage, radio-ulnar, 283 
 Fibrous zones of heart, 311 
 Fimbriae, Fallopian, 484 
 Fissure of Glaserius, 124 
 
 great transverse of brain, 80 
 
 of the helix, 121 
 
 sphenoidal, 98 
 
 Fissure 
 
 of Sylvius, 79 
 
 of the tragus, 1 21 
 Fissures of liver, 399 
 
 of Santorini, 122 
 Foramen incisivum, 139 
 
 lacerum anterius, 98 
 
 of Monroe, 63 
 
 optic, 98 
 
 ovale of heart, 302 
 
 sacro-sciatic, great, 538 
 small. 538 
 
 of Sommering, 108 
 
 subpubic, 539 
 
 of Winslow, 364 
 Foramina Thebesii, 304 
 Fovea elliptica, 128 
 
 hemispherica, 128 
 Fornix, 61 
 
 anterior crura of, 64 
 
 posterior crura of, 64 
 Fossa, amygdaloid, 147 
 
 innominata, 121 
 
 navicularis urethrae, 426 
 vaginae, 476 
 
 ovalis, 302 
 
 scaphoides, 120 
 Fossae, ischio -rectal, 459 
 
 nasal, 136 
 Fourchette, 476 
 Fraena epiglottidis, 150 
 
 of ileo-caecal valve, 397 
 Fraenulum labiorum, 476 
 Frsenum linguae, 145 
 
 preputii, 427, 429 
 
 Gall-bladder, 368, 402 
 Ganglia, cervical, inferior, 189 
 middle, 189 
 superior, 188 
 
 semi-lunar, 376 
 Ganglion of Andersch, 186 
 
 cardiac, 334 
 
 of cerebellum, 73 
 
 of Cloquet, 140 
 
 Gasserian, 82 
 
 impar, 454 
 
 lenticular, 94 
 
 of Meckel, 119 
 
 otic, 119 
 
 branches of, 120 
 . petrous, 186 
 
 spheno-palatine, 119 
 
 on spinal nerves, 290 
 
 submaxillary, 177 
 Genu of corpus callosum, 57 
 Gimbernat's ligament, 342 
 Gland, anti-prostatic, 467 
 
 epiglottic, 197 
 
 lachrymal, 45 
 
622 
 
 INDEX. 
 
 Gland 
 
 of Litre, 467 
 
 parotid, 32, 34 
 
 pineal, 65 
 
 pituitary, 79 
 
 prostate, 424, 437 
 
 thymus, 316 
 
 thyroid, 167 
 Glands, Brunner's, 394 
 
 Bartholine's, 481 
 
 ceruminous, 122 
 
 Cowper's, 426, 428, 466 
 
 inguinal, 492 
 
 labial, 144 
 
 lymphatic, 492 
 
 mammary, 208 
 
 Meibornian, 42 
 
 molar, 144 
 
 of Lieberkiihn, 394 
 
 Pacchionian, 54, 55 
 
 Peyer's, 394 
 
 solitary, 394 
 
 sublingual, 181 
 
 submaxillary, 176 
 
 tracheal, 324 
 
 vulvo- vaginal, 481 
 Glandula socia parotidis, 32 
 Glandulae agminatae, 394 
 
 odoriferJB, 429 
 
 Pacchioni, 54, 55 
 
 Tysoni, 429 
 'Glans clitoridis, 477 
 
 penis, 427 
 
 Glisson's capsule, 400 
 Globus, major epididymis, 431 
 
 minor epididymis, 431 
 Glottis, 201 
 Goose's foot of leg, 542 
 Graafian vesicles, 488 
 Gums, 144 
 
 Hamstring, inner, 543 
 
 outer, 543 
 Heart, 299 
 Helicotrema, 130 
 Helix, 120 
 
 Hernia, congenital, 357 
 crural, 489 
 diaphragmatic, 417 
 encysted, 357 
 femoral, 489 
 
 concealed, 499 
 inguinal, 349 
 direct, 356 
 indirect, 356 
 oblique, 356 
 scrotal, 357 
 ventro-inguinal, 356 
 Hey's ligament, 494 
 Hiatus aorticus, 419 
 
 Hippocampus major, 61 
 
 minor, 61 
 Hyaloid body, 108 
 
 membrane, 108 
 
 processes, 109 
 Hymen, 477 
 Hypothenar eminence, 278 
 
 Ileum, 371, 392 
 Incisura tragica, 120 
 Incus, 126 
 
 Infundibula of kidney, 407 
 Infundibulum of brain, 79 
 
 of ear, 130 
 
 of heart, 305 
 
 of nose, 138 
 
 Integument of breast, 208 
 Intercolumnar fibres, 350 
 Intestine, large, 395 
 
 small, 392 
 Iris, 105 
 
 Island of Reil, 60, 79 
 Isthmus, uteri, 487 
 
 of Vieussens, 302 
 
 Jejunum, 371, 392 
 Joint, ankle, 608 
 
 elbow, 281 
 
 hip, 520 
 
 knee, 595 
 
 shoulder, 243 
 
 temporo-maxillary, 115 
 
 wrist, 283 
 
 Kidneys, 374, 406 
 
 Labia majora, 475 
 
 minora, 476 
 Labyrinth, osseous, 127 
 
 membranous, 130 
 Lachrymal canals, 45 
 
 ducts, 45 
 
 gland, 45 
 
 papillae, 45 
 
 sac, 46 
 
 Lactiferous tubes, 209 
 Lacuna magna, 427 
 Lacus lachrymalis, 44 
 Lamina cinerea, 79 
 
 cornea, 61 
 
 cribrosa, 100 
 
 spiralis osseous, 130 
 
 membranacea, 130 
 Larynx, 192 
 Lens, crystalline, 109 
 LIGAMENTS, 
 
 of auricle of ear, 121 
 
 acromio-clavicular, superior, 243 
 inferior, 243 
 
 alar, 600 
 
INDEX. 
 
 623 
 
 LIGAMENTS continued. 
 
 annular, of ankle, anterior, 571 
 external, 572 
 internal, 556 
 
 of radius, 282 
 
 of wrist, anterior, 279 
 posterior, 273 
 arcuatum externum, 420 
 
 internum, 420 
 astragalo-scaphoid, 612 
 atlanto-axoid, anterior, 533 
 capsular, 533 
 posterior, 533 
 auricular, 121 
 
 extrinsic, 121 
 
 intrinsic, 121 
 of bladder, 366, 472 
 calcaneo-cuboid, 613 
 
 -scaphoid, 613 
 capsular, of the hip, 521 
 
 jaw, 116 
 
 pisiform bone, 284 
 
 shoulder, 244 
 
 thumb, 285 
 
 vertebrae, 529 
 of the carpus, dorsal, 284 
 
 lateral, 284 
 
 palmar, 284 
 ciliary, 103 
 conoid, 244 
 coracoid, 241, 244 
 coraco-acromial, 244 
 -clavicular, 244 
 -humeral, 244 
 coronary of liver, 363 
 
 of the knee, 605 
 costo-clavicular, 335 
 costo-sternal, 335 
 costo-transverse, external, 337 
 internal, 337 
 middle, 337 
 
 costo-vertebral anterior, 336 
 cotyloid of hip, 522 
 crico-thyroid, lateral, 197 
 
 middle, 197 
 crucial of knee, 602 
 cruciform, 534 
 denticulatum, 287 
 deltoid of ankle, 608 
 of the elbow, anterior, 281 
 
 lateral, 281 
 
 posterior, 282 
 Gimbernat's, 342, 539 
 glenoid of scapula, 245 
 Key's, 494 
 hip-joint, of the, 520 
 ilio-femoral, 522 
 ilio-vertebral, 535 
 inter-articular of hip, 523 
 inter-clavicular, 335 
 
 LIGAMENT s continued. 
 
 interosseous, astragalo-calca- 
 
 neoid, 611 
 interosseous tibio-fibular, 606 
 
 tibio-fibular, inferior, 607 
 interosseous, radio-ulnar, 283 
 
 of ribs, 336 
 inter-spinous, 530 
 inter-transverse, 530 
 intervertebral, 526 
 lateral of the ankle, 608 
 
 jaw, 115 
 
 knee, 599 
 of liver, 363 
 metacarpal dorsal, 285 
 
 palmar, 285 
 moderator, 532 
 mucosum, 600 
 oblique, radio-ulnar, 283 
 
 of the semilunar cartilages, 
 
 605 
 
 obturator, 539 
 
 occipito-atlantal anterior, 530 
 capsular, 530 
 lateral, 531 
 posterior, 530 
 occipito-axoid, 532 
 odontoid, 532 
 orbicular, of elbow, 282 
 
 of hip, 521 
 ovarian, 484 
 patella, 598 
 of phalanges of foot, 616 
 
 of fingers, 285 
 posticum of knee, 599 
 pterygo-maxillary, 117 
 Poupart's, 342, 539 
 pubic anterior, 539 
 
 posterior, 539 
 
 superior, 539 
 recto-uterine, 366 
 rhomboid, 335 
 sacro-coccygeal anterior, 535 
 
 posterior, 535 
 sacro-iliac, anterior, 536 
 oblique, 537 
 posterior, 536 
 sacro-vertebral, 535 
 sacro-sciatic anterior, 537 
 
 posterior, 537 
 sacciform, 283 
 stellate, 336 
 sterno-clavicular anterior, 335 
 
 posterior, 335 
 stylo-maxillary, 117 
 sub-flava, 529 
 sub-pubic, 539 
 supra-scapular, 241 
 supra-spinous, 529 
 suspensory, of clitoris, 477 
 
624 
 
 INDEX. 
 
 LIGAMENTS continued. 
 
 suspensory, of liver, 363 
 
 of penis, 341, 349, 429 
 tarsal, 610 
 
 tarso-metatarsal, 615 
 teres of hip, 523 
 of liver, 363 
 of uterus, 483 
 of thorax, 334 
 thyro-arytenoid, 198 
 thyro-hyoid, lateral, 197 
 
 middle, 197 
 
 tibio-fibular, anterior superior, 605 
 posterior superior, 605 
 anterior inferior, 607 
 posterior inferior, 607 
 transverse, 607 
 
 transverse, of the acetabulum, 522 
 of the atlas, 534 
 of the metatarsus, 615 
 of the scapula, 243 
 of the serailunar cartilages, 
 
 605 
 
 trapezoid, 244 
 triangular, of scapula, 244 
 of abdomen, 352 
 of perineum, 467 
 of uterus, broad, 366 
 vertebral, anterior common, 525 
 
 posterior, common, 525 
 wrist, lateral, 283 
 anterior, 283 
 posterior, 283 
 vesico-uterine, 366 
 Ligamentum patella), 598 
 latum pulinonis, 295 
 nuchge, 244, 530 
 Limbus luteus, 108 
 Linea alba, 344 
 Lineae transversse of abdomen, 344, 348 
 
 of corpus callosum, 57, 69 
 Linese semi-lunares, 344 
 Lips, 144 
 Liquor Cotunnii, 130 
 
 Morgagni, 110 
 Liver, 366, 398 
 Lobuli testis, 432 
 Lobes of the cerebrum, 80 
 of cerebellum, 70 
 olfactory, 81 
 Lobus caudatus, 399 
 
 pneumogastricus, 71 
 quadratus, 399 
 Spigelii, 399 
 Locus, niger, 77 
 
 perforatus lateralis, 79 
 
 medius, 78 
 planus, of heart, 306 
 Lungs, 325 
 Lung, root of, 326 
 
 Lymphatic vessels, arm, 249, 492 
 Lyra, 63 
 
 Macula cribrosa, 128 
 Malleus, 126 
 
 Massa carnei Jacobi Sylvii, 591 
 Mastoid cells, 124 
 Meatus auditorius externus, 122 
 internus, 131 
 
 urinarius, female, 477 
 
 male, 427 
 
 Meatuses of the nose, 137, 138 
 Meckel's ganglion, 119 
 Mediastinal space, 296 
 Mediastinum, anterior, 297 
 
 middle, 297 
 
 posterior, 297, 315 
 
 superior, 297, 315 
 
 testis, 432 
 Medulla oblongata, 73 
 
 spinalis, 289 
 Meibomian glands, 42 
 Membrana Jacobi, 106, 107 
 
 pigmenti, 106 
 
 pupillaris, 106 
 
 Ruysclyana, 106 
 
 tyinpani, 123 
 Membrane, choroid, 106 
 
 crico-thyroid, 198 
 
 hyaloid, 108 
 
 sacciform, 283 
 Membranes of the brain, 52 
 Membranous part of the urethra, 425, 
 
 437 
 
 Mesentery, 364 
 Meso-caecum, 365 
 Meso-colon, ascending, 365 
 
 descending, 365 
 
 transverse, 363 
 Meso-rectum, 366 
 Mitral valves, 308 
 Modiolus, 130 
 Mons Veneris, 475 
 Morsus diaboli, 484 
 Mouth, 143 
 Mucous membrane of trachea, 324 
 
 of stomach, 390 
 
 of small intestines, 393 
 
 of large intestines, 396 
 MUSCLES, 
 
 abductor minimi digiti manus, 278 
 
 abductor minimi digiti pedis, 593 
 
 abductor pollicis manus, 277 
 pollicis pedis, 587 
 internus secundi digiti pedis, 594 
 externus secundi digiti pedis, 
 
 595 
 
 tertii digiti pedis, 595 
 quart! digiti pedis, 595 
 
 accelerator urinse, 464 
 
INDEX. 
 
 625 
 
 MUSCLE s contimied. 
 
 accessorius ad sacro-lumbalem, 233 
 
 adductor, brevis, 509 
 longus, 508 
 magnus, 510, 545 
 pollicis manus, 278 
 pollicis pedis, 592 
 tertii digiti pedis, 593 
 quarti digiti pedis, 593 
 minimi digiti pedis, 594 
 minimi digiti manus, 278 
 
 anconeus, 268 
 
 anti-tragicus, 121 
 
 arytenoideus, 200 
 
 aryteno-epiglottici, 200 
 
 attollens aurem, 48 
 
 attrahens aurem, 48 
 
 of auricles of heart, 312 
 
 azygos uvulae, 150 
 
 of Bell, 424 
 
 biceps flexor cruris, 541 
 cubiti, 250 
 
 brachialis anticus, 254 
 externus, 256 
 internus, 254 
 
 buccinator, 37 
 
 caninus, 39 
 
 cervicalis ascendens, 231 
 descendens, 231 
 
 coccygeus, 459 
 
 complexus, 230 
 
 compressor nasi, 39 
 
 compressores urethras, 468 
 
 constrictor, of pharynx, inferior, 203 
 middle, 203 
 superior, 203 
 
 coraco-brachialis, 252 
 
 corrugator supercilii, 42 
 
 cremaster, 346 
 
 crico-arytenoideus, lateralip, 201 
 posticus, 200 
 
 crico-thyroideus, 199 
 
 crureus, 507 
 
 deltoid, 238 
 
 depressor anguli oris, 37 
 labii inferioris, 37 
 
 superioris alaeque nasi, 39 
 
 diaphragm, 417 
 
 digastricus, 165 
 
 erector clitoridis, 477 
 penis, 464 
 spinae, 233 
 
 extensor carpi radialis brevior, 268 
 carpi radialis longior, 268 
 carpi ulnaris, 270 
 digiti minimi manus, 270 
 digitorum brevis pedis, 575 
 digitorum communis manus, 269 
 digitorum longus pedis, 573 
 indicis, 272 
 
 53 
 
 MUSCLE s continued. 
 
 extensor ossis metacarpi pollicis 
 
 manus, 272 
 primi internodii pollicis manus, 
 
 272 
 
 pollicis proprius pedis, 575 
 secundi internodii pollicis ma- 
 nus, 272 
 flexor accessorius pedis, 591 
 
 brevis digiti minimi manus, 
 
 278 
 
 brevis digiti minimi pedis, 593 
 carpi radialis, 260 
 
 ulnaris, 261 
 
 digitorum, brevis pedis, 586 
 profundus manus, 266, 276 
 sublimis manus, 261, 276 
 longus, digitorum pedis, 564 
 
 pollicis pedis, 565 
 ossis metacarpi pollicis manus, 
 
 277 
 pollicis brevis, 278 
 
 pedis, 591 
 longus manus, 266 
 gastrocnemius, 557 
 gemellus inferior, 518 
 
 superior, 518 
 genio-hyo-glossus, 154 
 
 -hyoideus, 179 
 gluteus maximus, 511 
 medius, 513 
 minimus, 514 
 gracilis, 503 
 of Guthrie, 468 
 of the heart, 305 
 helicis major, 121 
 
 minor, 121 
 of Homer, 42 
 hyo-glossus, 154, 180 
 iliacus internus, 417 
 infra-spinatus, 241 
 inter-costal external, 292 
 
 internal, 292 
 interossei manus, 279 
 pedis dorsales, 595 
 pedis plantares, 594 
 inter-spinales, 236 
 inter-transversales, 236 
 latissimus dorsi, 222, 225 
 laxator tympani, 127 
 levator anguli oris, 39 
 anguli scapulae, 229 
 ani, 467 
 
 glandulse thyroideae, 167 
 labii inferioris, 37 
 superioris, 38 
 superioris, alaeque nasi, 39 
 menti, 37 
 palati, 150 
 palpebrae, 92 
 
626 
 
 INDEX. 
 
 MUSCLE s continued. 
 
 levatores costarum, 235 
 
 longiores costarum, 236 
 
 urethras, 468 
 longissimus dorsi, 233 
 longus colli, 190 
 lumbricales manus, 276 
 
 pedis, 591 
 masse ter, 111 
 multifidus spinae, 235 
 mylo-hyoideus, 179 
 obliquus abdominis externus, 342 
 
 abdominis internus, 345 
 
 capitis inferior, 237 
 superior, 237 
 
 oculi inferior, 97 
 superior, 92 
 obturator externus, 519 
 
 internus, 518 
 occipito-frontalis, 48 
 omo-hyoideus, 163 
 opponens pollicis, 277 
 orbicularis oris, 36 
 
 palpebrarum, 41 
 palato-glossus, 151 
 palato-pharyngeus. 204 
 palmaris brevis, 273 
 
 longus, 260 
 pectineus, 508 
 pectoralis major, 210 
 
 minor, 213 
 peroneus brevis, 582 
 
 longus, 581 
 
 tertius, 574 
 pi an tar is, 557 
 
 platysma myoides, 31, 36, 157 
 popliteus, 563 
 pronator quadratus, 267 
 
 radii teres, 259 
 psoas magnus, 416 
 
 parvus, 416 
 pterygoideus externus, 112 
 
 internus, 113 
 pyramidalis abdominis, 349 
 
 nasi, 39 
 pyriformis, 518 
 quadratus femoris, 519 
 
 lumborum, 234 
 
 menti, 37 
 
 quadriceps extensor cruris, 506 
 rectus abdominis, 348 
 
 anticus major, 189 
 
 anticus minor, 189 
 
 capitis lateralis, 190 
 
 capitis posticus major, 236 
 minor, 236 
 
 femoris, 507 
 
 oculi, external, 96 
 inferior, 96 
 internal, 96 
 
 Mu s c LE s continued. 
 
 rectus oculi, superior, 93 
 retrahens aurem, 49 
 rhomboideus major, 228 
 
 minor, 228 
 risorius novus, 36 
 sacro-lumbalis, 233 
 sartorius, 502 
 scalenus anticus, 175 
 
 medius, 175 
 
 posticus, 175 
 semi-spinalis colli, 235 
 
 dorsi, 235 
 semi-membranosus, 542 
 
 -tendinosus, 542 
 serratus, magnus, 220 
 
 posticus inferior, 228 
 
 superior, 228 
 of small intestine, 392 
 
 large, 396 
 soleus, 558 
 sphincter ani externus, 458 
 
 internus, 421 
 sphincter vaginae, 481 
 
 vesicae, 424 
 spinalis dorsi, 234 
 splenius capitis, 229 
 
 colli, 229 
 stapedius, 127 
 
 sterno-cleido-mastoideus, 162 
 sterno-hyoideus, 163 
 
 -thyroideus, 163 
 of stomach, 388 
 stylo-glossus, 154, 179 
 
 -hyoideus, 165 
 
 -pharyngeus, 181, 204 
 subclavius, 214 
 subcrureus, 508 
 sub scapular is, 221 
 supinator radii brevis, 271 
 
 longus, 268 
 supra-spinous, 236 
 supra-spinatus, 239 
 temporal, 49 
 tensor, palati, 151 
 
 tarsi, 42 
 
 tympani, 127 
 
 vaginae femoris, 501 
 teres major, 221, 242 
 
 minor, 242 
 thyro-arytenoideus, 201 
 
 -epiglottici, 200 
 
 -hyoideus, 163 
 tibialis anticus, 572 
 
 posticus, 566 
 tongue, intrinsic, of, 153 
 tracheal, 324 
 trachelo-mastoideus, 230 
 tragicus, 121 
 transversalis abdominis, 346 
 
INDEX. 
 
 627 
 
 MUSCLE s continued. 
 
 transversalis, colli, 230 
 
 pedis, 593 
 transversus, auricula?, 121 
 
 perinei, 464 
 
 alter, 464 
 trapezius, 224 
 triangularis nasi, 39 
 
 oris, 37 
 
 sterni, 293 
 
 triceps extensor cubiti, 222, 242, 255 
 of ureters, 424 
 vastus externus, 501, 507 
 
 internus, 507 
 of ventricles of heart, 312 
 of Wilson, 468 
 zygomaticus, major, 38 
 
 minor, 38 
 
 Musculi papillares, 304 
 pectinati, 304, 307 
 
 Naboth's ovula, 487 
 Nasal duct, 46, 137 
 
 fossae, 136 
 Neck, regions of, 165, 166 
 
 superficial parts of, 155 
 
 deep parts of, 184 
 
 NERVES, 
 
 abducentes, 82 
 
 acromial, 161 
 
 articular of knee, 547, 548 
 
 auditory, 83, 131 
 
 auricularis magnus, 32, 160 
 
 auricular, of pneumogastric, 187 
 
 posterior, 35 
 buccal, 36, 113 
 
 branches, 33 
 cardiac, inferior, 334 
 
 middle, 189, 333 
 
 superior, 189, 333 
 cerebral, classification of, 84, 85 
 
 origin of, 80 
 
 chorda tympani, 113, 133 
 ciliary, 94, 104 
 circumflex, 222, 239, 217 
 coccygeal, 449 
 communicans, peronei, 548, 554 
 
 tibialis, 547, 554 
 crural, anterior, 415, 504 
 cutaneous, external brachial, 216, 
 246, 258 
 
 of abdomen, 341 
 
 internal, of arm, 216, 246, 258 
 
 lesser internal, of Wrisberg, 
 219, 246 
 
 peroneal, 556 
 
 posterior femoral, 541, 556 
 dental anterior, 118 
 
 inferior, 36, 113 
 
 NERVE s continued. 
 
 dental, posterior inferior, 118 
 
 superior, 115, 117 
 descendens noni, 182 
 digital of foot, 569, 580 
 dorsal, posterior, 232 
 eighth pair, 83 
 facial, 34, 35, 83. 132 
 
 cervical branch of, 161 
 fifth pair, 82 
 first pair, 80 
 fourth pair, 82, 92 
 frontal, 50, 91 
 genito-crural, 414, 492 
 glosso-pharyngeal, 83, 181, 186 
 gluteal inferior, 515 
 
 superior, 448, 515 
 gustatory, 177 
 
 hemorrhoidal, inferior, 451, 517 
 hypoglossal, 83, 177, 186 
 infra-orbital, 36, 38, 117 
 infra-trochlear, 94 
 ilio-scrotal, 360 
 intercostal, 294, 348, 358 
 intercosto-humeral, 220, 246 
 interosseous, anterior, of arm, 267 
 
 posterior of arm, 271 
 of Jacobson, 131, 133 
 lachrymal, 92 
 laryngeal, inferior, 168, 202, 318 
 
 superior, 182, 188, 202 
 lingual, 113 
 lumbar, 413 
 
 posterior, 232 
 lumbo-sacral, 415, 448 
 malar, 33, 97 
 masseteric, 111, 112 
 maxillary branches, 33 
 median, 216, 265, 275 
 musculo-cutaneous of abdomen, in- 
 ferior, 414, 492 
 middle, 360, 492 
 superior, 360, 492 
 
 arm, 246 
 
 leg, 548, 569, 580 
 musculo-spiral, arm. 217, 246, 254 
 mylo-hyoid, 113, 177 
 nasal, 36, 93 
 
 external, 94 
 
 internal, 36, 93, 141 
 naso-palatine, 140 
 ninth pair, 83 
 obturator, 415, 447, 509 
 
 accessory, 415, 447, 509 
 occipital is major, 51, 232 
 
 minor, 51, 160 
 oculo-motor, 81 
 olfactory, 80, 140 
 optic, 81, 96 
 palatine, 119 
 
628 
 
 INDEX. 
 
 NERVE S continued. 
 
 palatine, anterior, 119, 141 
 palmar, median, 275 
 
 ulnar, deep, 275, 279 
 
 superficial, 275 
 par vagum, 83, 168, 187 
 pathetic, 82, 92 
 penis, dorsal of, 453 
 perineal, 452 
 
 cutaneous, 453 
 
 superficial, 452, 457 
 peroneal, 548 
 petrosal, superficial, 120 
 pharyngeal, 187 
 phrenic, 174, 297, 316 
 plantar, external, 590 
 
 internal, 590 
 
 pneumogastric, 83, 168, 187, 317 
 popliteal, external, 544, 548 
 
 internal, 544, 546 
 portio dura, 34, 35, 83, 132 
 
 mollis, 83, 131 
 pudendal, inferior, long, 453 
 
 superior, long, 452 
 pudic, internal, 452, 517 
 radial, 263 
 
 respiratory, external, of Bell, 219 
 sacral, anterior, 448 
 
 posterior, 232 
 saphenous, external, 547, 554 
 
 internal, 500, 552, 555 
 
 peroneal, 548 
 sciatic, great, 453, 516, 544 
 
 small, 453, 517 
 second pair, 81 
 seventh pair, 83 
 sixth pair, 82 
 spheno-palatine, 119, 140 
 spinal accessory, 83, 182, 187, 227 
 splanchnic, great, 333 
 
 lesser, 333 
 suboccipital, 232 
 subscapular, 219 
 superficial colli, 161 
 supra-clavicular, 161 
 supra-orbital, 50 
 
 supra-scapular, 175, 227, 240, 242 
 sympathetic, 188, 413, 454 
 temporales profunda, 112 
 temporo-auricular, 114 
 third pair, 81 
 thoracic, inferior, 214 
 
 long, 219 
 
 superior, 211, 212 
 tibial, anterior, 548, 579 
 
 posterior, 546, 563 
 trifacial, 82 
 trigeminal, 82 
 tympanic, 131 
 ulnar, 217, 254, 265, 275 
 
 NERVE s continued. 
 
 uterine, 455 
 
 j Vidian, 119, 131, 132 
 Plexus of, 
 
 axillary, 216 
 
 cardiac, 333, 334 
 
 carotid, 185 
 
 cervical, posterior, 232 
 
 coronary of heart, 314 
 of stomach, 378 
 
 cystic, 379 
 
 gastric, 376 
 
 gastro-duodenal, 379 
 
 gastro-epiploic, left, 378 
 right, 379 
 
 guise, 318 
 
 hemorrhoidal, 454 
 
 hepatic, 373, 376, 379 
 
 hypogastric, 454 
 
 lumbar, 413 
 
 mesenteric, inferior, 383 
 superior, 376, 383 
 
 orbital, 99 
 
 ovarian, 455 
 
 pancreatico-duodenal, 379 
 
 phrenic, 376 
 
 prostatic, 454 
 
 pulmonary, anterior, 318 
 posterior, 318 
 
 pyloric, 379 
 
 renal, 376, 385 
 
 sacral, 449 
 
 solar, 375 
 
 spermatic, 385 
 
 splenic, 376, 378 
 
 tympanic, 134 
 
 vaginal, 455 
 
 vesical, 454 
 Nervi molles, 189 
 Nodulus cerebelli, 68 
 Nose, 134 
 Nymphae, 476 
 Nares, anterior, 134 
 posterior, 149 
 
 (Esophagus, 315, 328 
 Omentum gastro-colic, 364 
 
 gastro-hepatic, 363 
 
 gastro splenic, 365 
 
 lesser, 363 
 
 majus, 364 
 Optic commissure, 81 
 
 thalami, 60 
 
 tract, 81 
 
 Orbiculare, os, 126 
 Origin of cerebral nerves, 80 
 Os uteri, externum, 485 
 internum, 487 
 Os tincse, 485 
 Ossicula auditus, 125 
 
INDEX. 
 
 629 
 
 Otolithes, 131 
 
 Ovaries, 488 
 
 Ovula of Naboth, 487 
 
 Pacchionian glands, 54, 55 
 Palate, half arches of, 147 
 
 soft, 147, 149 
 Pancreas, 373, 404 
 Papilla?, 145 
 
 calyciforuies, 146 
 
 conicse, 146 
 
 fungiformes, 146 
 
 of kidney, 407 
 
 lachrymal, 45 
 Parotid gland, 32, 34 
 Peduncles, of corpus callosum, 79 
 
 of pineal gland, 64 
 Pelvis of kidney, 407 
 Penis, 427 
 Pericardium, 298 
 Pericranium, 49 
 Perilymph, 130 
 Perineal centre, 458 
 
 pockets, 461 
 Perineum, female, 482 
 
 male, 455 
 Peritoneum, 362 
 Pes hippocampi, 61 
 Pharynx, 148, 203 
 Pia mater, of brain, 53 
 
 of cord, 287 
 Pillars, of fornix. 64 
 
 of external abdominal ring, 350 
 Pineal gland, 65 
 Pituitary gland, 79 
 Pleura costalis, 296 
 
 diaphragmatica, 296 
 
 mediastinalis, 295 
 
 pulmonalis, 295 
 Plica semilunaris, 44 
 Pons, Tarini, 78 
 
 Varolii, 77 
 
 hepatis, 400 
 Popliteal space, 545 
 Portio dura, 83, 132 
 
 mollis, 83, 131 
 Porus opticus, 100 
 Poupart's ligament, 342 
 Prepuce of penis, 429 
 Preputium clitoridis, 477 
 Processus caudatus, 121 
 
 cerebelli ad testes, 68 
 
 cochleariformis, 124 
 
 gracilis, 126 
 
 vermiformis inferior, 72 
 
 superior, 71 
 Promontory, 124 
 Prostate gland, 424, 437 
 Prostatic part of the urethra, 425 
 Pulmonary artery, 300, 306, 321, 328 
 
 Pulmonary veins, 302, 307, 321, 328 
 Puncta lachryinalia, 45 
 Pupil, 105 
 Pylorus, 391 
 Pyramid, of ear, 124 
 
 of thyroid gland, 167 
 
 of Ferrein, 408 
 
 Raphe of corpus callosum, 57 
 Receptaculum chyli, 329, 415 
 Rectum, 373, 420, 435 
 Rete testis, 433 
 Retina, 107 
 Rima vaginae, 475 
 glottidis, 202 
 
 Ring, abdominal, external, 344 
 Rostrum of corpus callosum, 57 
 
 Sac, lesser peritoneal, 364 
 Sacculus of ear, 130 
 
 laryngis, 202 
 Saphenous opening, 493, 494 
 
 crescentic margin of, 494 
 semi-lunar margin of, 494 
 
 vein, internal, 491, 553 
 
 external, 540, 546, 554 
 Scala, vestibular, 129 
 
 tympanic, 129 
 Sclerotic coat. 100 
 Scrotum, 430 ' 
 Semicircular canals, 128 
 
 membranous, 130 
 Semilunar valves, 306, 309 
 Septum, auricularum, 307 
 
 cochleariforme, 125 
 
 crurale, 495 
 
 lucidum of brain, 59 
 
 pectiniforme, 428 
 Sheath, infundibuliform, 497 
 Shoulder, 238 
 Sigmoid, flexure of colon, 372 
 
 valves, 306, 309 
 Sinus, auricular, 307 
 
 cavernous, 89, 99 
 
 circular, 89 
 
 lateral, 88 
 
 longitudinal inferior, 55 
 superior, 54 
 
 occipital, 88 
 
 palpebral, 44 
 
 petrosal inferior, 89 
 superior, 89 
 
 pocularis, 425 
 
 portal, 401 
 
 prostatic, 425 
 
 straight, 88 
 
 transverse, 89 
 
 venosus of heart, 302 
 Sinuses, of Valsalva, 306, 309 
 
 of uterus, 447 
 
630 
 
 INDEX. 
 
 Soft palate, 147, 149 
 Spheno-maxillary region, 110 
 Sphincter vesicae, 424 
 Spinal canal, 286 
 
 cord, 289 
 Spleen, 366, 405 
 Spongy part of the urethra, 426 
 Stapes, 126 
 Steno's duct, 32 
 Stomach, 366, 368, 387 
 Subarachnoid, spaces, 75 
 
 space of cord, 287 
 Sublingual gland, 181 
 Submaxillary gland, 176 
 Substantia gelatinosa, 290 
 
 spongiosa, 290 
 
 Supra-renal capsules, 374, 409 
 Suspensory ligament, of the liver, 363 
 
 of the penis, 341, 349, 429 
 Sympathetic nerve, 188, 331 
 Symphysis pubis, 538 
 Synovial, fringes of knee, 601 
 
 membrane of hip, 524 
 of jaw, 116 
 of knee, 600 
 Tapetum, 106 
 Taenia semicircularis, 60 
 
 hippocampi, 62 
 Tarsal cartilages, 43 
 Tendo Achillis, 559 
 
 palpebrarum, 41 
 Tentorium cerebelli, 87 
 Testicles, 430 
 Thalamus nervi optici, 60 
 Thoracic duct, 191, 315, 329 
 Thorax, 291 
 Thyroid cartilage, 194 
 
 gland, 167 
 Tongue, 152 
 
 nerves of, 154 
 
 Topography of mouth, fauces, and pha- 
 rynx, 143 
 Tonsils, 148 
 
 of cerebellum, 68 
 Torcular Herophili, 54 
 Trachea, 321 
 Tragus, 120 
 Tricuspid valves, 305 
 Trigone vesicale, 423 
 Tripod of Haller, 376 
 Tuber cinereum, 79 
 Tubercula quadrigemina, 66 
 Tubercalum Loweri, 302 
 Tubes of Ferrein, 408 
 Tubuli recti, 433 
 
 seminiferi, 432 
 
 uriniferi, 408 
 Tunica, albuginea testis, 431 
 
 serosa, 101, 104 
 
 vaginalis testis, 431 
 
 Tunica vasculosa testis, 432 
 Tympanum, 123 
 Tyson's glands, 429 
 
 Ureters, 374, 409 
 Urethra, female, 482 
 
 male, 425 
 Uterus, 483 
 Utriculus, 130 
 Uvea, 105 
 Uvula cerebelli, 68 
 
 palati, 149 
 
 vesicae, 424 
 
 Vagina, 478 
 
 columns of, 479 
 Valve of Bauhin, 397 
 
 of brain, 68 
 
 Eustachian, 303 
 
 ileo-cascal, 397 
 
 ileo-colic, 397 
 
 mitral, 308 
 
 of Thebesius, 304 
 
 tricuspid, 305 
 Valves, semilunar, 306 
 
 sigmoid, 306, 309 
 Valvulae conniventes, 393 
 Vasa recta, 433 
 
 brevia, 376 
 
 efferentia, 433 
 
 vorticosa, 100, 104 
 Vas aberrans, 434 
 
 deferens, 433 
 VEINS, 
 
 axillary, 218 
 
 azygos, major, 315, 330 
 minor, 330 
 superior, 330 
 
 basilic, 246 
 
 median, 246 
 
 bronchial, 317, 322 
 
 cava ascendens, 412 
 
 descendens, 300, 317 
 
 cephalic, 211, 212, 245 
 
 communicans, of arm, 246, 248 
 
 coronary, of heart, 304, 314 
 of stomach, 378 
 
 of corpora cavernosa, 429 
 
 dorsalis penis, 429 
 
 dorsal of foot, 570 
 
 dorsal arch of foot, 570 
 
 emissaries of Santorini, 52 
 
 facial, 158 
 
 femoral, 505 
 
 of forearm, superficial, 257 
 
 Galeni, 64 
 
 of head, superficial, 52 
 
 hepatic, 400, 402 
 
 innominata, 168, 316 
 
 internal maxillary, 115 
 
INDEX. 
 
 681 
 
 VE IN s contimied. 
 
 intercostal superior, 317 
 iliac, common, 413 
 
 internal, 445 
 ilio-lumbar, 445 
 jugular, anterior, 158 
 
 external, 158 
 
 internal, 168, 185, 192 
 of leg, deep-seated, 562, 579 
 median, 24G 
 
 cephalic, 245 
 mammary, internal, 317 
 mesenteric, superior, 382 
 
 inferior, 383 
 ophthalmic, 90 
 ovarian, 446 
 popliteal, 546, 549 
 portal, 401 
 
 profunda femoris, 506 
 pulmonary, 302, 307, 321, 328 
 pericardiac, 317 
 phrenic, superior, 317 
 renal, 385 
 sacral, lateral, 445 
 
 middle, 445 
 saphenous, internal, 491, 553 
 
 external, 540, 546, 554 
 spermatic, 385, 435, 446. 
 of the spinal cord, 288 
 splenic, 376 
 subclavian, 174 
 supra-renal, 386 
 transversa, 317 
 thyroid, inferior, 317 
 thymic, 317 
 umbilical, 400 
 uterine, 447 
 
 VE i N s continued. 
 Plexus of, 
 
 choroides, 61 
 
 hemorrhoidal, 421, 446 
 
 pampiniformis, 435 
 
 tracheal, 166 
 
 vaginal, 447 
 
 vesico-prostatic, 446 
 Velum, interpositum, 63 
 
 medullare*, posterior, 68 
 Venae comites, brachial, 254 
 Vena portae, 401 
 Ventricle of Arantius, 68 
 Ventricles of the brain, 
 
 fifth, 59 
 
 fourth, 67 
 
 lateral, 59 
 
 third, 64 
 of the heart, right, 300, 301, 304 
 
 left, 300, 301, 308 
 of the larynx, 201 
 Vermiform processes, 71, 72 
 Verumontanum, 425 
 Vesical triangle, 423 
 Vesiculse seminales, 434 
 Vestibule, 128 
 Vestibulum vagina?, 477 
 Villi, 393 
 
 Viscera, abdominal, relations of, 366 
 Vesicles, Graafian, 488 
 Vitreous humor, 108 
 Vulva, 475 
 
 Wharton's duct, 177, 179 
 
 Zonula of Zinn, 109 
 Zones of heart, fibrous, 311 
 
 THE END. 
 
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 Cases and many Engravings. Twelfth edition, with the Author's last Improvements and 
 Corrections. In one octavo volume, of 600 pages. 
 
 DEWEES (W. P.), M. D. A TREATISE ON THE PHYSICAL AND MEDICAL TREATMENT OF CHILDREN. 
 Tenth edition. In one volume, octavo, 548 pages. 
 
 DEWEES (W. P.), M. D. A TREATISE ON THE DISEASES OF FEMALES. Tenth edition. In one 
 volume, octavo, 532 pages, with plates. 
 
 DRUITT (ROBERT), M.R.C.S. THE PRINCIPLES AND PRACTICE OF MODERN SURGERY. A new 
 American, from the improved London edition. Edited by F. W. Sargent, M. D.. author of 
 " Minor Surgery," &c. Illustrated with one hundred and ninety-three wood-engravings. 
 In one very handsomely-printed octavo volume, of 576 large pages. 
 
 DUNGLISON, FORBES, TWEEDIE, AND CONOLLY. THE CYCLOPEDIA OF PRACTICAL MEDI- 
 CINE : comprising Treatises on the Nature and Treatment of Diseases. Materia Medica and 
 Therapeutics, Diseases of Women and Children, Medical Jurisprudence, &c. &c. In four 
 large super-royal octavo volumes, of 3254 double-columned pages, strongly and hand- 
 somely bound. 
 
 *** This work contains no less than four hundred and eighteen distinct treatises, contri- 
 buted by sixty-eight distinguished physicians. 
 
 DUNGLISON (ROBLEY), M. D. MEDICAL LEXICON; a Dictionary of Medical Science, con- 
 taining a concise Explanation of the various Subjects and Terms of Physiology, Pathology, 
 Hygiene, Therapeutics, Pharmacology, Obstetrics, Medical Jurisprudence, &c. With the 
 French and other Synonymes; Notices of Climate and of celebrated Mineral Waters; For- 
 mulae for various Officinal, Empirical, and Dietetic Preparations, &c. Thirteenth edition, 
 revised. In one very, thick octavo volume, of over 900 large double-columned pages, 
 strongly bound in leather, with raised bands. (Just Issued.) 
 
BLANCH ARD & LEA'S MEDICAL PUBLICATIONS. 5 
 
 DUNGLISON (ROBLEY), M. D. THE PRACTICE OF MEDICINE. A Treatise on Special Pathology 
 and Therapeutics. Third edition. In two large octavo volumes, of 1500 pages. 
 
 DUNGLTSON (ROBLEY), M. D. GENERAL THERAPEUTICS AND MATERIA MEDICA: adapted fora 
 Medical Text-hook. Fifth edition, much improved. With one hundred and eighty-seven 
 illustrations. In two large and handsomely printed octavo volumes, of about 1100 pages. 
 (Just hsua'..) 
 
 DUNGLTSON (ROBLEY), M. D. NEW REMEDIES, WITH FORMULAE FOR THEIR PREPARATION AND 
 ADMINISTRATION. Seventh Edition, with extensive Additions. In one very large octavo 
 volume, of 770 pages. (Now Heady.) 
 
 DUNGLISON (ROBLEY), M. D. HUMAN PHYSIOLOGY. Eighth edition. Thoroughly revised 
 and extensively modified and enlarged, with over 500 illustrations. In, two large and 
 handsomely printed octavo volumes, containing about 1500 pages. 
 
 DICKSON (S. II.), M. D. ELEMENTS OF MEDICINE: a Compendious View of Pathology and 
 Therapeutics, or the History and Treatment of Diseases. In one large and handsome 
 octavo volume of 750 pages, leather. (Just Issued.) 
 
 DE JONGH (L. J.), M. D. THE THREE KINDS OF COD-LIVER OIL. comparatively considered, with 
 their Chemical and Therapeutic Properties. Translated, with an Appendix and Cases, by 
 Edward Carey. M. D. To which is added an article on the subject from " Dunglison on 
 New Remedies." In one small 12mo. volume, extra cloth. 
 
 DAY (GEORGE E.), M. D. A PRACTICAL TREATISE ON THE DOMESTIC MANAGEMENT AND MORE 
 IMPORTANT DISEASES OF ADVANCED LIFE. "With an Appendix on a new and successful mode 
 of treating Lumbago and other forms of Chronic Rheumatism. One volume octavo, 226 
 pages. 
 
 ELLIS (BENJAMIN), M. D. THE MEDICAL FORMULARY ; being a Collection of Prescriptions, 
 derived from the writings and practice of many of the most eminent physicians of America 
 and Europe. Together with the usual Dietetic Preparations and Antidotes for Poisons. 
 To which is added an Appendix on the Endermic use of Medicines, and on the use of Ether 
 and Chloroform. The whole accompanied with a few brief Pharmaceutic and Medical 
 Observations. Tenth edition, revised and much extended, by Robert P. Thomas, M.D., 
 Professor of Materia Medica in the Philadelphia College of Pharmacy. In one neat octavo 
 volume of 296 pages. 
 
 ERICHSEN (JOHN). THE SCIENCE AND ART OF SURGERY; being a Treatise on Surgical Inju- 
 ries. Diseases, and Operations. With Notes and Additions by the American editor. Illus- 
 trated with over 300 engravings on wood. In one large and handsome octavo volume of 
 nearly 900 closely printed pages. 
 
 FLINT (AUSTIN), M. D. PHYSICAL EXPLORATION AND DIAGNOSIS OF DISEASES AFFECTING THE 
 RESPIRATORY ORGANS. In one handsome octavo volume, extra cloth, of 636 pages. (Now 
 Ready.) 
 
 FERGUSSON (WILLIAM). F. R. S. A SYSTEM OF PRACTICAL SURGERY. Fourth American, from 
 the third and enlarged London edition. In one large and beautifully printed octavo 
 volume of about 700 pages, with 393 handsome illustrations. 
 
 FFTOK (CHARLES), M.D. RENAL AFFECTIONS: their Diagnosis and Pathology. With illus- 
 trutions. One volume, royal 12mo., extra cloth. 
 
 FOWNES (GEORGE\ PH. D. ELEMENTARY CHEMISTRY, Theoretical and Practical. With 
 numerous illustrations. A. new American, from the last and revised London edition. 
 Edited, with Additions, by Robert Bridge.';. M.D. In one large royal 12mo. volume, of 
 over 550 pages, with 181 wood-cuts : sheep, or extra cloth. (Now Ready.) 
 
6 BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 
 
 GRAHAM (THOMAS), F.R.S. THE ELEMENTS OF CHEMISTRY. Including the Application of 
 the Science to the Arts. With numerous illustrations. With Notes and Additions, by 
 Robert Bridges, M. D., etc., etc. Second American, from the second and enlarged London 
 
 PART I. (Lately Issued) large 8vo., 430 pages, 185 illustrations. 
 PART II. (Preparing) to match. 
 
 GROSS (SAMUEL D.), M. D. A PRACTICAL TREATISE ON THE DISEASES, INJURIES, AND MALFOR- 
 MATIONS OF THE URINARY BLADDER, THE PROSTATE GLAND, AND THE URETHRA. Second edition, 
 revised and much enlarged, with 184 illustrations. In one very large and handsome octavo 
 volume of over 900 pages, extra cloth or leather. ( Just Issued.) 
 
 GROSS (SAMUEL D.), M.D. A PRACTICAL TREATISE ON FOREIGN BODIES IN THE AIR-PASSAGES. 
 In one handsome octavo volume, with illustrations. 
 
 GROSS (SAMUEL D.), M. D. ELEMENTS OF PATHOLOGICAL ANATOMY; illustrated by colored 
 engravings and 250 wood-cuts. Second and revised edition. In one large imperial octavo 
 volume of 822 pages, leather. 
 
 GROSS (SAMUEL D.), M.D. A SYSTEM OF SURGERY; Diagnostic, Pathological, Therapeutic 
 and Operative. With very numerous engravings on wood. (Preparing.) 
 
 GLUGE (GOTTLIEB), M.D. AN ATLAS OF PATHOLOGICAL HISTOLOGY. Translated, with Notes 
 and Additions, by Joseph Leidy, M. D., Professor of Anatomy in the University of Penn- 
 sylvania. In one volume, very large imperial quarto, with 320 figures, plain and colored 
 on twelve copper-plates. 
 
 GRIFFITH (ROBERT E.), M.D. A UNIVERSAL FORMULARY, containing the Methods of Pre- 
 paring and Administering Officinal and other Medicines. The whole adapted to Physicians 
 and Pharmaceutists. Second edition, thoroughly revised, with numerous Additions, by 
 Robert P. Thomas, M. D., Professor of Materia Medical in the Philadelphia College of Phar- 
 macy. In one large and handsome octavo volume of over 600 pages, double columns. 
 
 GRIFFITH (ROBERT E.), M.D. MEDICAL BOTANY; or, a Description of all the more impor- 
 tant Plants used in Medicine, and of their Properties, Uses, and Modes of Administration. 
 In one large octavo volume of 704 pages, handsomely printed, with nearly 350 illustrations 
 on wood. 
 
 GARDNER (D. PEREIRA), M. D. MEDICAL CHEMISTRY, for the use of Students and the Pro- 
 fession: being a Manual of the Science, with its Applications to Toxicology, Physiology, 
 Therapeutics, Hygiene, Ac. In one handsome royal 12mo. volume, with illustrations. 
 
 HASSE (C. E.), M. D. AN ANATOMICAL DESCRIPTION OF THE DISEASES OF RESPIRATION AND CIR- 
 CULATION. Translated and edited by Swainc. In one volume, octavo. 
 
 HARRISON (JOHN), M. D. AN ESSAY TOWARDS A CORRECT THEORY OF THE NERVOUS SYSTEM. 
 In one octavo volume, 292 pages. 
 
 HUGHES (H. M.), M.D. A CLINICAL INTRODUCTION TO THE PRACTICE OF AUSCULTATION, and 
 other Modes of Physical Diagnosis, in Diseases of the Lungs and Heart. Second American 
 from the second and improved London edition. In one royal 12mo. volume. (Just Ready.) 
 
 IIOXiNER (WILLIAM E.), M. D. SPECIAL ANATOMY AND HISTOLOGY. Eighth edition. Exton- 
 eively revised and modified. In two large octavo volumes, of more than 1000 pages, hand- 
 somely printed, with over 300 illustrations. 
 
 JIOBLYN (RICHARD D.), A. M. A DICTIONARY OF THE TERMS USED TN MEDICINE AND THE COT/. 
 LATERAL SCIENCES. Second and improved American edition. Revised, with numerous Ad- 
 ditions, from the second London edition, by Isaac Hays, M. D., &c. In one large royal 
 12mo. volume, of over 500 pages, double columns. (Now Ready.) 
 
BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 7 
 
 HAMILTON (FRANK H.) A TREATISE ON FRACTURES AND DISLOCATIONS. In one handsome 
 octavo volume. With numerous illustrations. (Preparing.) 
 
 IIERSCHEL (SIR JOHN F. W.), F. R. S. OUTLINES OF ASTRONOMY. New American, from the 
 third London edition. In one neat volume, crown octavo, with six plates and numerous 
 wood-cuts. 
 
 HDMBOLDT (ALEXANDER). ASPECTS OF NATURE TN DIFFERENT LANDS AND DIFFERENT CLI- 
 MATES. Second American edition, one vol. royal 12mo., extra cloth. 
 
 JONES (T. WHARTON), F. R. S. THE PRINCIPLES AND PRACTICE OF OPHTCTALMIC MEDICINE AND 
 SURGERY. Second American, from the second and revised English edition. With Addition? 
 by Edward Hartshorne, M. D. In one very neat volume, large royal 12mo., of 500 pages, 
 with 110 illustrations. 
 
 JONES (C. HANDFIELD), F.R.S., AND EDWARD H. SIEVEKING, M.D. A MANUAL OP 
 PATHOLOGICAL ANATOMY. With 397 engravings on wood. In one handsome volume, octavo, 
 of nearly 750 pages, leather. (Lately Issued.) 
 
 KIRKES (WILLIAM SENHOTJSE), M.D., AND JAMES PAGET, F.R. S. A MANUAL OF PHT- 
 SIOLOGY. Second American, from the second and improved London edition. With 165 
 illustrations. In one large and handsome royal 12mo. volume. 550 pages. 
 
 KNAPP (F.), PH. D. TECHNOLOGY; or, Chemistry applied to the Arts and to Manufactures. 
 Edited, with numerous Notes and Additions, by Dr. Edmund Ronalds and Dr. Thomas 
 Richardson. First American edition, with Notes and Additions, by Professor Walter R. 
 Johnson. In two handsome octavo volumes, printed and illustrated in the highest style 
 of art, with about 500 wood- engravings. 
 
 LEIIMANN (G. C.) PHYSIOLOGICAL CHEMISTRY. Translated from the second edition by George 
 E. Day, M.D. Edited by R. E. Rogers, M.D. With illustrations selected from Funke's 
 Atlas of Physiological Chemistry, and an Appendix of Plates. Complete in two handsome 
 octavo volumes, extra cloth, containing 1200 pages. With nearly 200 illustrations. (Just 
 Issued.) 
 
 LEHMANN (G. C.) MANUAL OF CHEMICAL PHYSIOLOGY. Translated from the German, with 
 Notes and Additions, by J. C. Morris, M. D. With an introductory Essay on Vital Force, 
 by Samuel Jackson, M. D. In one handsome octavo volume, extra cloth, of 336 pages. 
 With numerous illustrations. (Now Meady.) 
 
 LEE (ROBERT), M. D. CLINICAL MIDWIFERY ; comprising the Histories of Five Hundred and 
 Forty-five Cases of Difficult, Preternatural, and Complicated Labor, with Commentaries. 
 From the second London edition. In one royal 12mo. volume, extra cloth, of 238 pages. 
 
 L A ROCHE (R.), M.D. PNEUMONIA; its Supposed Connection, Pathological and Etiological, 
 with Autumnal Fevers, including an Inquiry into the Existence and Morbid Agency of 
 Malaria. In one handsome octavo volume, extra cloth, of 500 pages. 
 
 LA ROCHE (R.), M.D. YELLOW FEVER, considered in its Historical, Pathological, Etiological, 
 and Therapeutical Relations. Including a Sketch of the Disease as it has occurred in 
 Philadelphia from 1699 to 1854, with an Examination of the Connections between it and 
 the Fevers known under the same name in other Parts of Temperate, as well as in Tropical 
 Regions. In two large and handsome octavo volumes, of nearly 1500 pages, extra cloth. 
 (Just Issued.) 
 
 LAWRENCE (W.), F. R. S. A TREATISE ON DISEASES OF THE EYE. A new edition, edited, with 
 numerous Additions, and 243 illustrations, by Isaac Hays, M. D.. Surgeon to Wills' Hos- 
 pital, etc. In one very large and handsome octavo volume of 950 pages, strongly bound 
 in leather, with raised bands. 
 
8 BLANCIIARD & LEA'S MEDICAL PUBLICATIONS. 
 
 LALLEMAND (M.). THE CAUSES, SYMPTOMS, AND TREATMENT OF SPERMATORRHOEA. Translated 
 and edited by Henry J. McDougal. In one volume, octaTO, of 320 pages. Second Ame- 
 rican edition. 
 
 LARDNER (DIOXYSTUS), B.C. L. HANDBOOKS OF NATURAL PHILOSOPHY AND ASTRONOMY. 
 Revised, with numerous Additions, by the American editor. FIRST COURSE, containing 
 Mechanics, Hydrostatics, Hydraulics, Pneumatics, Sound, arid Optics. In one large royal 
 12mo. volume, of 750 pages, with 424 wood-cuts. SECOND COURSE, containing Heat. Elec- 
 tricity, Magnetism, and Galvanism, one volume, large royal 12nio.. of 450 pages, with 250 
 illustrations. THIRD COURSE (now ready'), containing Meteorology and Astronomy, in one 
 large volume, royal 12mo., of nearly 800 pages, with 37 plates and 200 wood-cuts. The 
 whole complete in three volumes, of about 2000 large pages, with over 1000 figures on steel 
 and wood. 
 
 MEIGS (CHARLES D.), M.D. WOMAN: HER DISEASES AND THEIR REMEDIES. A Series of Lec- 
 tures to his Class. Third and improved edition. In one large and beautifully-printed 
 octavo volume. 
 
 MEIGS (CHARLES D.), M. D. OBSTETRICS : THE SCIENCE AND THE ART. Second edition, 
 revised and improved. With 131 illustrations. In one beautifully-printed octavo volume, 
 of 752 large pages. 
 
 METGS (CHARLES D.), M. D. A TREATISE ON ACUTE AND CHRONIC DISEASES OF THE NECK OF 
 THE UTERUS. With numerous plates, drawn and colored from nature, in the highest style 
 of art. In one handsome octavo volume, extra cloth. 
 
 MEIGS (CHARLES D.), M. D. OBSERVATIONS ON CERTAIN OF THE DISEASES OF YOUNG CHILDREN. 
 In one handsome octavo volume, of 214 pages. 
 
 MEIGS (CHARLES D.), M.D. ON THE NATURE, SIGNS, AND TREATMENT OF CHILDBED FEVER; 
 in a Series of Letters addressed to the Students of his Class. In one handsome octavo 
 volume, extra cloth, of 365 pages. 
 
 MILLER (JAMES). F. R. S. E. PRINCIPLES OF SURGERY. Fourth American, from the third and 
 revised Edinburgh edition. In one large and very beautiful volume of 700 pages, with 240 
 exquisite illustrations on wood. 
 
 MILLER (JAMES), F.R.S.E. THE PRACTICE OF SURGERY. Third American, from the second 
 Edinburgh edition. Edited, with Additions, by F. W. Sargent, M.D., one of the Surgeons 
 to Wills' Hospital, etc. Illustrated by 319 engravings on wood. In one large octavo 
 volume of over 700 pages. 
 
 MALGATGNE f.T. F.). OPERATIVE SURGERY, based on Normal and Pathological Anatomy. 
 Translated from the French, by Frederick Brittan, A. B., M. D. With numerous illustra- 
 tions on wood. In one handsome octavo volume, of nearly 600 pages. 
 
 MOHR (FRANCIS), Pn. D., AND REDWOOD (TTTEOPHILTTS). PRACTICAL PHARMACY. Com- 
 prising the Arrangements, Apparatus, and Manipulations of the Pharmaceutical Shop 
 and Laboratory. Edited, with extensive Additions, by Prof. William Procter, of the Phi- 
 ladelphia College of Pharmacy. In one handsomely-printed octavo volume, of 570 page.-, 
 with over 50o engravings on wood. 
 
 MACLISE (JOSEPH). SURGICAL ANATOMY. Forming one volume, very large imperial quarto. 
 With sixtv-eight large and splendid Plates, drawn in the best style, and beautifully 
 colored. Containing 190 Figures, many of them the size of life. Together with copious 
 and explanatory letter-press. Stroiigly and handsomely bound in extra cloth, being one 
 of the cheapest and best executed Surgical works as yet issued in this country. 
 Copies can be sent by mail, in five parts, done up in stout covers. 
 
BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 9 
 
 MAYNE (JOHN), M.D. A DISPENSATORY AND THERAPEUTICAL REMEMBRANCER. Comprising 
 the entire lists cf Materia Medica, with every Practical Formula contained in the three 
 British Pharmacopoeias. In one 12mo. volume, extra cloth, of over 300 large pages. 
 
 MACKENZIE (W.), M. D. A PRACTICAL TREATISE ON DISEASES AND INJURIES OF THE EYE. To 
 which is prefixed an Anatomical Introduction, by T. Wharton Jones. From the fourth 
 revised and enlarged London edition. With Notes and Additions by Addinell Hewson, 
 M.D. In one very large and handsome octavo volume, with numerous wood-cuts and 
 plates. 1028 pages, leather, raised bands. (Just Issued.) 
 
 NEILL (JOHN). M. D., AND FRANCIS GURNEY SMITH, M. D. AN ANALYTICAL COMPENDIUM 
 OP THE VARIOUS BRANCHES OF MEDICAL SCIENCE; for the Use and Examination of Students. 
 Second edition, revised and improved. In one very large and handsomely printed royal 
 12nio. volume of over 1000 pages, with 350 illustrations on wood. Strongly bound in 
 leather, with raised bands. 
 
 NEILL (JOHN), M.D. OUTLINES OF THE ARTERIES. 1 vol. 8vo., handsome colored plates. 
 
 OUTLINKS OF THE NERVES. 1 vol. 8vo., with handsome plates. OUTLINES OF THE VEINS AND 
 
 LYMPHATICS, 1 vol. 8vo., handsome colored plates. 
 Also, the three works done up in one handsome volume, half bound. 
 
 NELIGAN (J. MOORE), M.D. ATLAS OF CUTANEOUS DISEASES. In one beautiful quarto 
 volume, extra cloth, with splendid colored plates, presenting nearly one hundred elaborate 
 representations of disease. (Now Heady.) 
 
 NELIGAN (J. MOORE), M. D. A PRACTICAL TREATISE ON DISEASES OF THE SKIN. In one neat 
 royal 12mo. volume, of 334 pages. 
 
 OWEN (PROF. R.) ON THE DIFFERENT FORMS OP THE SKELETON. One royal 12mo. volume, 
 with numerous illustrations. 
 
 PANCOAST (J.), M. D. OPERATIVE SURGERY; or, A Description and Demonstration of the 
 various Processes of the Art; including all the New Operations, and exhibiting the state 
 of Surgical Science in its present advanced condition. Complete in one royal 4to. volume 
 of 380 pages of letterpress description and eighty large 4to. plates, comprising 486 illus- 
 trations. Second edition, improved. 
 
 PARKER (LANGSTON). THE MODERN TREATMENT OF SYPHILITIC DISEASES, BOTH PRIMARY AND 
 SECONDARY : comprising the Treatment of Constitutional and Confirmed Syphilis, by a safe 
 and successful method. With numerous Cases, Formulae, and Clinical Observations. 
 From the third and entirely rewritten London edition. In one neat octavo volume. 
 
 PERETRA (JONATHAN), M. D. THE ELEMENTS OF MATERIA MEDICA AND THERAPEUTICS. Third 
 American edition, enlarged .ind improved by the author; including Notices of most of the 
 Medical Substances in use in the civilized world, and forming an Encyclopasdia of Materia 
 Mi'dica. Edited, with Additions, by Joseph Carson, M.D., Professor of Materia Medica and 
 Pharmacy in the University of Pennsylvania. In two very large octavo volumes of 2100 
 pages, on small type, with over 450 illustrations. (Now Complete.) 
 
 PARRISII (EDWARD). AN INTRODUCTION TO PRACTICAL PHARMACY. Designed as a Text-book 
 for the Student, and as a Guide for the Physician and Pharmaceutist. With many For- 
 mula and Prescriptions. In one handsome octavo volume, extra cloth, of 550 pages, 
 with 243 illustrations. (Now Heady.) 
 
 PEASELEE (E. R.), M. D. HUMAN HISTOLOGY, in its Applications to Physiology and General 
 Pathology, designed as a Text-book for Medical Students. With numerous illustrations. 
 In one handsome royal 12mo. volume. (Preparing.) 
 
 PJRRTK (WILLIAM), F. R. S.E. THE PRINCIPLES AND PRACTICE OF SURGERY. Edited by John 
 Neill. M. D.. Demonstrator of Anatomy in the University of Pennsylvania, Surgeon to the 
 Pennsylvania Hospital, etc. In one very handsome octavo volume of 780 pages, with 316 
 illustrations. 
 
 RAMSBOTHAM (FRANCIS H.), M.D. THE PRINCIPLES AND PRACTICE OF OBSTETRIC MEDICINE 
 AND SURGERY, In reference to the Process of Parturition. A new and enlarged edition, 
 thoroughly revised by the author. With Additions by W. V. Keating, M. D. In one large 
 and handsome imperial octavo volume of 650 pages, strongly bound in leather, with raised 
 bands. With sixty-four beautiful plates, and numerous wood-cuts in, the text, containing 
 in all nearly 200 large and beautiful figures. (Just Issued.) 
 
10 BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 
 
 RICORD (P.), M.D. ILLUSTRATIONS OF SYPHILITIC DISEASE. Translated from the French, by 
 Thomas F. Betton, M. D. With the addition of a History of Syphilis, and a complete Bibli 
 ography and Formulary of Remedies, collated and arranged by Paul B. Goddard, M.D. 
 With fifty large quarto plates, comprising 117 beautifully colored illustrations. In one 
 large and handsome quarto volume. 
 
 RICORD (P.), M. D. A TREATISE ON THE VENEREAL DISEASE. By John Hunter, F. R. S. With 
 copious Additions, by Ph. Ricord, M.D. Edited, with Notes, by Freeman J. Bumstead, 
 M. D. In one handsome octavo volume, with plates. 
 
 RICORD (P.), M. D. LETTERS ON SYPHILIS, addressed to the Chief Editor of the Union Medi- 
 cale. With an Introduction, by Amedee Latour. Translated by W. P. Lattimore, M.D. 
 In one neat octavo volume. 
 
 ROKITANSKY (CARL). A MANUAL OF PATHOLOGICAL ANATOMY. Translated from the Ger- 
 man by W. E. Swaine, Edward Sieveking, M.D., C. II. Moore, and George E. Day, M.D. 
 Complete, four volumes bound in two, extra cloth, of about 1200 pages. (Just Issued.) 
 
 RIG BY (EDWARD), M. D. A SYSTEM OF MIDWIFERY. With Notes and Additional Illustra- 
 tions. Second American edition. One volume octavo, 422 pages. 
 
 RO YLE (J. FORBES), M. D. MATERIA MEDICA AND THERAPEUTICS ; including the Preparations 
 of the Pharmacopoeias of London, Edinburgh, Dublin, and of the United States. With 
 many new Medicines. Edited by Joseph Carson, M. D., Professor of Materia Medica and 
 Pharmacy in the University of Pennsylvania. With ninety-eight illustrations. In one 
 large octavo volume of about 700 pages. 
 
 SKEY (FREDERICK C.), F. R. S. OPERATIVE SURGERY. In one very handsome octavo volume 
 of over 650 pages, with about 100 wood-cuts. 
 
 SHARPEY (WILLIAM), M.D., JONES QUAIN, M.D., AND RICHARD QUAIN, F. R. S., etc. 
 HUMAN ANATOMY. Revised, with Notes and Additions, by Joseph Leidy, M.D. Complete 
 in two large octavo volumes, of about 1300 pages. Beautifully illustrated with over 500 
 engravings on wood. 
 
 SMITH (HENRY H.), M. D., AND WILLIAM E. HORNER, M. D. AN ANATOMICAL ATLA8 
 illustrative of the Structure of the Human Body. In one volume, large imperial octavo, 
 with about 660 beautiful figures. 
 
 SMITH (HENRY H.), M.D. MINOR SURGERY; or, Hints on the Every-day Duties of the 
 Surgeon. With 247 illustrations. Third and enlarged edition. In one handsome royal 
 12mo. volume of 456 pages 
 
 SARGENT (F. W.), M.D. ON BANDAGING AND OTHER OPERATIONS OF MINOR SURGERY. Second 
 edition, enlarged. In one handsome royal 12mo. volume of nearly 400 pages, with 182 
 illustrations. (Just Issued.) 
 
 STILLE (ALFRED), M. D. PRINCIPLES OF THERAPEUTICS. In one handsome volume. (Pre- 
 paring.) 
 
 SIMON (JOHN), F. R, S. GENERAL PATHOLOGY, as conducive to the Establishment of Rational 
 Principles for the Prevention and Cure of Disease. A Course of Lectures delivered at St. 
 Thomas's Hospital during the Summer Session of 1850. In one neat octavo volume. 
 
 SMITH (W. TYLER), M. D. ON PARTURITION, AND THE PRINCIPLES AND PRACTICE OF OBSTETRICS, 
 In one large duodecimo volume of 400 pages. 
 
 SMITH (W. TYLER), M.D. THE PATHOLOGY AND TREATMENT OF LEUCORRHOEA. With nume- 
 rous illustrations. In one very handsome octavo volume, extra cloth, of about 250 pages. 
 
BLANCHARD & LEA'S MEDICAL PUBLICATIONS. 11 
 
 SOLLY (SAMUEL), F.R.S. THE HUMAN BRAIN; its Structure, Physiology, and Diseases. 
 TV'ith a Description of the Typical Forms of the Brain in the Animal Kingdom. From the 
 Second and much enlarged London edition. In one octavo volume, with 120 wood-cuts. 
 
 SCH(EDLER (FRIEDRICII), Pn. D. THE BOOK OF NATURE; an Elementary Introduction to 
 the Sciences of Physics, Astronomy, Chemistry. Mineralogy, Geology, Botany. Zoology, and 
 Physiology. First American edition, with a Glossary and other Additions and Improve- 
 ments; from the second English edition. Translated fron* the sixth German edition, by 
 Henry Medlock, F.C.S., &c. In one thick volume, small octavo, of about 700 pages, with 
 679 illustrations on wood. Suitable for the higher schools and private students. ,(Nbw 
 JReady.) 
 
 TAYLOPi (ALFRED S.), M. D., F. R. S. MEDICAL JURISPRUDENCE. Fourth American, from the 
 fifth and improved English edition. With Notes and References to American Decisions, 
 by Edward Hartshorne, M. D. In one large octavo volume of 700 pages. (Now Heady.) 
 
 TAYLOR (ALFRED S.), M. D. ON POISONS, IN RELATION TO MEDICAL JURISPRUDENCE AND MEDI- 
 CINE. Edited, with Notes and Additions, by R. E. Griffith, M.D. In one large octavo 
 volume of 688 pages. 
 
 TANNER (T. H.), M. D. A MANUAL OF CLINICAL MEDICINE AND PHYSICAL DIAGNOSIS. To which 
 is added, The Code of Ethics of the American Medical Association. In one neat volume, 
 small 12mo., extra cloth, or flexible. (Just Issued.) 
 
 TOMES (JOHN), F.R.S. A MANUAL OF DENTAL PRACTICE. Illustrated by numerous engravings 
 on wood. In one handsome volume. (Preparing.) 
 
 TODD (R. B.), M.D., AND WILLIAM BOWMAN, F.R.S. PHYSIOLOGICAL ANATOMY AND PHYSI- 
 OLOGY OF MAN. With numerous handsome wood-cuts. Parts I., II., and III., in one octavo 
 volume, 552 pages. Part IV. will complete the work. 
 
 WATSON (THOMAS), M.D., &c. LECTURES ON THE PRINCIPLES AND PRACTICE OF PHYSIC. 
 Third American, from the last London edition. Revised, with Additions, by D. Francis 
 Condie, M.D., author of a "Treatise on the Diseases of Children," &c. In one octavo 
 volume, of nearly 1100 large pages, strongly bound, with raised bands. 
 
 WALSHE (W. H.), M. D. DISEASES OF THE HEART, LUNGS, AND APPENDAGES; their Symptoms 
 and Treatment. In one handsome volume, large royal 12mo., 512 pages. 
 
 WHAT TO OBSERVE AT THE BEDSIDE AND AFTER DEATH, IN MEDICAL CASES. Published tinder the 
 authority of the London Society for Medical Observation. In one very handsome volume, 
 royal 12mo., extra cloth. 
 
 WILDE (W. R.). AURAL SURGERY, AND THE NATURE AND TREATMENT OF DISEASES OF THE EAR. 
 In one handsome octavo volume, with illustrations. 
 
 WHITEHE AD (JAMES), F. R. C. S., &c. THE CAUSES AND TREATMENT OF ABORTION AND STE- 
 RILITY; being the Result of an Extended Practical Inquiry into the Physiological and 
 Morbid Conditions of the Uterus. Second American Edition. In one volume, octavo, 368 
 pages 
 
 WEST (CHARLES), M.D. LECTURES ON THE DISEASES OF INFANCY AND CHILDHOOD. Second 
 American, from the second and enlarged London edition. In one volume, octavo, of nearly 
 500 pages. 
 
12 BLANCHABD & LEA'S MEDICAL PUBLICATIONS. 
 
 WEST (CHARLES), M. D. AN INQUIRY INTO THE PATHOLOGICAL IMPORTANCE OF ULCEBATION OF 
 THE Os UTERI. Being the Croonian Lectures for the year 1854. In one neat octavo volume, 
 extra cloth. 
 
 WEST (CHARLES), M. D. LECTURES ON THE DISEASES OF WOMEN. In two Parts. Part I, 
 Diseases of the Uterus : Part II, Diseases of ihe Ovaries, etc., the Bladder, Vagina, and 
 External Organs. 
 
 V Publishing in the "MEDICAL NEWS AND LIBRARY" for 1856 and 1857. 
 
 WILSON (ERASMUS), M.D.. F. R.S. A SYSTEM OF HUMAN ANATOMY, General and Special. 
 Fourth American, from the last English edition. Edited by Paul B. Goddard, A.M., M.D. 
 With 250 illustrations. Beautifully printed, in one large octavo volume, of nearly 600 
 pages. 
 
 WILSON (ERASMUS), M.D., F.R.S. THE DISSECTOR'S MANUAL; Practical and Surgical Ana- 
 tomy. Third American, from the last revised and enlarged English edition. Modified and 
 rearranged by William Hunt, M.D. In one large and handsome royal 12mo. volume, 
 leather, of 582 pages, with 154 illustrations. (Wow Heady.) 
 
 WILSON (ERASMUS), M.D., F.R.S. ON DISEASES OF THE SKIN. Third American, from the 
 third London edition. In one neat octavo volume, of about 500 pages, extra cloth. 
 
 WILSON (ERASMUS), M. D., F. R. S. ON CONSTITUTIONAL AND HEREDITARY SYPHILIS, AND ON 
 SYPHILITIC ERUPTIONS. In one small octavo volume, beautifully printed, with four exqui- 
 site colored plates, presenting more than thirty varieties of Syphilitic Eruptions. 
 
 WILSON (ERASMUS), M.D., F.R.S. HEALTHY SKIN; a Treatise on the Management of the 
 Skin and Hair in Relation to Health. Second American, from the fourth and improved 
 London edition. In one handsome royal 12mo. volume, extra cloth, with numerous illus- 
 trations. Copies may also be had in paper covers, for mailing, price 75 cents. (Now Heady.) 
 
 WILLIAMS (C. J.B.), M.D., F.R.S. PRINCIPLES OF MEDICINE; comprising General Pathology 
 and Therapeutics, and a brief general view of Etiology, Nosology, Semeiology, Diagnosis, 
 Prognosis, and Hygienics. Edited, with Addition?, by Meredith Clynier, M.D. ^Fourth 
 American, from the last and enlarged London edition. In one octavo volume, of 476 pages. 
 
 . . 
 
 WILLIAMS (C. J. B.), M. D., F.R.S. A PRACTICAL TREATISE ON DISEASES OF THE RESPIRATORY 
 ORGANS; including Diseases of the Larynx, Trachea, Lungs, and Pleurae. With numeroug 
 Additions and Notes, by M. Clymer, M.D. With wood-cuts. In one octavo volume, pp. 508. 
 
 YOU ATT (WILLIAM), V. S. THE HORSE. A new edition, with numerous illustrations; 
 together with a General History of the Horse; a Dissertation on the American Trotting 
 Horse; how Trained and Jockeyed; an Account of his Remarkable Performances; and an 
 Essay on the Ass and the Mule. By J. S. Skinner, formerly Assistant Postmaster-General, 
 and Editor of the Turf Register. One large octavo volume. 
 
 TOU ATT (WILLIAM), V. S. THE DOG. Edited by E. ,T. Lewis, M. D. With numerous and 
 beautiful illustrations. In one very handsome volume, crown Svo., crimson cloth, gilt 
 
 Blanchard & Lea have now ready a detailed Catalogue of their publications, in Medical and 
 other Sciences, with Specimens of the Wood-engravings, Notices of tbe Press, &c. &c., forming 
 a pamphlet of sixty-four large octavo pages. It has been prepared without regard to expense, 
 and may be considered as one of the handsomest specimens of printing as yet executed in 
 this country. Copies will be sent free, by post, on receipt of two three-cent postage stamps. 
 
 Detailed Catalogues of their publications, Miscellaneous, Educational, Medical, &c. } fur- 
 nished gratis, on application. 
 

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