UC-NRLF C 3 D37 MOD MEDICAL SCHL LflTOAI&Y EX 1 1BKIS ffi MEMORIAM DR. JOHN MARSHALL WILLIAMS! INCLUDING A SPECIAL SECTION ON THE FUNDAMENTAL PRINCIPLES OF ANATOMY EDITED HY W. T. ECKLEY, M. D. I'KOFESSOK OF ANATOMY IN THE COLLEGE OF PHYSICIANS AND SURGEONS, UNIVERSITY OF ILLINOIS ; PROFESSOR OF ANATOMY IN THE NORTHWESTERN UNIVERSITY DENTAL SCHOOL; PROFESSOR OF ANATOMY IN THE CHICAGO CLINICAL SCHOOL, AND DIRECTOR OF THE CHICAGO SCHOOL OF ANATOMY AND PHYSIOLOGY; MEMBER OF THE AMERICAN MEDICAL ASSOCIATION, THE CHICAGO PATHOLOGICAL SOCIETY, THE CHICAGO MEDICAL SOCIETY, THE MEDICO- LEGAL SOCIETY OF CHICAGO, ETC. AND MRS. CORINNE BUFORD ECKLEY INSTRUCTOR IN ANATOMY IN THE NORTHWESTERN UNIVERSITY DENTAL SCHOOL; PROFESSOR OF ANATOMY IN THE NORTHWESTERN UNIVERSITY WOMAN'S MEDICAL SCHOOL; PROFESSOR OF ANATOMY IN THE CHICAGO SCHOOL OF ANATOMY AND PHYSIOLOGY WITH 347 ILLUSTRATIONS, MANY OF WHICH ARE IN COLORS PHILADELPHIA P. BLAKISTON'S SON & CO. 1012 WALNUT STREET 1899 COPYRIGHT, 1899, BY P. BLAKISTON'S SON & Co. PRESS OF WM. F. FELL & Co., !22O-24 SANSOM ST., PHILADELPHIA. PREFACE We have the honor of submitting this little book as a dissecting-room guide to " Morris' Human Anatomy." The growing tendency to specialize in the practice of medicine has reacted on the branch of medical science that continges every medical specialty anatomy ; with the result that our schools are compelled to keep pace in teaching this branch. Those areas of the body that can not, under existing conditions, be profitably studied in the dissecting-room are properly presented by the lecturer on anatomy. Thus the student has the benefit of the professor's dissections and investigation, and the additional opportunity for minute, detailed dissection and study, which he could not enjoy in the dissecting-room, where gross anatomy is the main topic. The minute and descriptive anatomy are, then, to be studied in Morris. In this book the gross anatomy only will be considered. For instance, the contents of the orbit, as the nerves, vessels, muscles, as found on the cadaver, will be considered, but the anatomy of the eyeball will not be taken up. The gross anatomy of the peritoneum and other abdominal contents will be con- sidered, while the student will be referred to Morris for the special anatomy of each individual organ. Several pages have been devoted to the sympathetic nerve, which every student should thoroughly dissect, for the purpose only of teaching the student to find on the cadaver the relation between sympathetic and their parent somatic nerves. The method of studying structures in the normal order in which they are exposed in dissection is followed, it is believed, as nearly as it is possible to accomplish this very desirable end. To aid the memory in fixing salient points seen in dissection, frequent review quizzes are given. In the introductory chapter are certain rules, principles, and generalizations which underly, to greater or less extent, the science of anatomy. It may be urged that matters of this nature are too elementary for medical students. How- ever this may be, experience teaches that students, even after having studied the subject for months, have a memory well stored with anatomical terms which are mere abstract ideas ; they are too often ignorant of the fundamental principles of our nomenclature. If anatomy is a nomenclaturic science [Can any department of learning be a science without a nomenclature?] then certainly the place for the student to 285 "'6 iv PREFA CE. learn this nomenclature is in school. The practice ot assuming too much knowl- edge on the part of the student I believe to be wrong in principle. At any rate, we must remember that this book is written, not for those who know anatomy, but for beginners. To impress on the student the necessity of tracing muscles to their exact origin and insertion, illustrations of bones having such attachments indicated in color have been introduced. These and nearly all other illustrations are from the work to which the text most frequently refers " Morris' Anatomy." We wish also to express our thanks to both author and publisher for the use of the excellent diagrams from Potter's " Compend of Anatomy," and for the many illustrations of the muscles taken from Gould's (Illustrated) " Medical Dic- tionary." In addition to these we have contributed about sixty original draw- ings, for the most part diagrammatic. We wish also to express our thanks to Dr. Theodor Tieken, Dr. F. R. Sherwood, and Dr. D. Loring for valuable suggestions and to Dr. W. A. Mansfield in particular, who read the original copy and made timely corrections. A book that would fail to give due consideration to those structures of the body which can be easily demonstrated on the cadaver by any careful student would fall short of the objects of this work. A book that would attempt in approximately 400 pages to give the same that Morris devotes 1400 pages to, would, to be charitable, be just 1000 pages too small. The sequence of structures revealed by dissection, and the great number of illustrations in the book, render an index almost superfluous. In fact, by the aid of the description of the illustration a given muscle or vessel can be found with certainty, even without an index. Still, to make the book as convenient as possible, a brief index is appended. W. T. ECKLEY. C. B. ECKLEY. 5816 SOUTH PARK AVE., CHICAGO. CONTENTS. PACK FUNDAMENTAL PRINCIPLES OF ANATOMY, 9 Anatomical Nomenclature, , 9 Anatomical Tissues, The, 13 THE HEAD AND NECK, 27 Head, Bones of, 27 Nerves, 31 Muscles, 32 Arteries, 37 Veins, 39 Glands, 4 Neck, Superficial Dissection, 43 Deep Cervical Fascia, 47 Muscles, 49 Glands, 51 Second Layer of Deep Cervical Fascia, 53 Third Layer of Deep Cervical Fascia, 57 Veins, Arteries, and Nerves, 58 Mouth, The, 79 Structures Seen in Mouth, 79 Muscles of Mastication, 93 Soft Palate 98 Pharynx, 99 Larynx, 106 Nasal Fossae, The Internal Nose, m Coverings of the Brain, 120 Tympanum, or Middle Ear, 13* Blood-supply to the Brain, 135 Orbit and its Contents, 139 SHOULDER, ARM, FOREARM, AND HAND, 152 Hand, Bones of, 152 Veins, 154 Muscles, 160 Nerves, 162 Arteries, 166 Arm, Bones of, 168 Arteries, 173 Muscles, 174 Nerves, 181 Shoulder, Bones of, 186 Axillary Space, 188 Veins and Muscles, 189 Nerves, 195 Arteries, . 196 THE THORAX, 198 Muscles of, 200 Nerves, - 201 Arteries, 204 Interior of the Thorax, 204 Contents, 205 Arteries, 211 Veins, 212 Nerves, 214 THE ABDOMEN 225 The Walls, 225 Spermatic Cord, ... 231 Interior View of Abdominal Walls, 235 The Peritoneum, 238 Abdominal Contents, 246 The Sympathetic Nerve, 261 V vi CONTENTS. THE PELVIS, CONTENTS OF, 274 The Diaphragm, 285 Female Generative Organs, 291 THIGH AND LEG, 297 Bones of, 297 Superficial Fascia, 302 Veins, Nerves, 305 Deep Fascia, 307 Anterior Region of the Leg, 310 Anterior and Internal Regions of the Thigh, 315 PELVIC OUTLET (MALE), 330 Muscles, 331 PELVIC OUTLET (FEMALE), 340 External and Internal Organs of Generation, 340 POSTERIOR PART OF SHOULDER, ARM, FOREARM, AND HAND, 345 Muscles, 353 Nerves 355 POSTERIOR PART OF LOWER EXTREMITY, 365 The Popliteal -Space, 366 Gluteal Region, .... 370 Arteries and Nerves, 372 Back Part of the Leg, 377 Sole of the Foot, 385 THE BACK, MUSCLES OF 394 Nerves, 397 Arteries, 398 SUMMARY OF CRANIAL NERVES, 398 ARTICULATIONS LIGAMENTS, 421 Table of Various Classes of Joints, 423 Pelvis Its Articulations and Ligaments, 453 Vertebral Column Its Articulations and Ligaments, 460 Thorax Its Articulations and Ligaments, 468 SOME INTERESTING FACTS ABOUT VF.INS 473 INDEX, 477 LIST OF ILLUSTRATIONS. 1. Displacement of Cotton by Growing Plants, 16 2. Connective Tissue Displaced by the Artery, Nerve, and Vein, 16 3. Triangular Muscle, 18 4. Quadrangular Muscle, 18 5. fusiform Muscle, 18 6. Clubbed Muscle, 18 7. The Skull. (Norma lateralis.) {Coloured}, 27 8. The Mandible. (Outer view.) (Coloured}, 28 9. The Mandible. (Inner view.) (Coloured} 28 10. The Skull. (Norma facialis.) (Coloured}, 29 11. The Skull. (Norma basilaris.) (Coloured}, 30 12. Primary Incisions in Dissection of the Face, 3 2 13. The Deeper Layer of the Muscles of the Face and Neck, 33 14. The Superficial Muscles of the Head and Neck, 34 15. Scheme of Facial Nerve Communicating with the Fifth Cranial Nerve, .... After Potter 35 16. Superficial Distribution of the Facial and Other Nerves of the Head (Coloured}, After Hirschfeld and Leveille 36 17. Scheme of the Facial Artery (Coloured}, 38 18. The Superficial Veins and Lymphatics of the Scalp, Face, and Neck (Coloured}, 39 19. Showing Schematically the Deep Part of the Parotid Gland Embracing the Styloid Process, . . 40 20. The Salivary Glands, 4 1 21. Cervical Triangles, 4 2 22. Superficial Branches of the Cervical Plexus (Coloured}, . . . After Hirschfeld and Leveille 46 23. Superficial Lymphatics, 47 24. Deep Cervical Fascia Transverse Section. Schematic, .' 48 25. Muscles of the Face and Neck, From Gould' s Illustrated Medical Dictionary 50 26. Scheme of Upper Attachments of and Special Names for Deep Cervical Fascia, 51 27. Thyroid Body, with Middle Lobe and Levator Muscle, 52 28. Scheme of Superior Thyroid Artery (Coloured}, 53 29. The Loop Formed by Communicating Branches, After Potter 54 30. The Muscles Attached to the Back of the Sternum, 54 31. Vessels and Nerves of Head and Neck, . . . From Gould's Illustrated Medical Dictionary 59 32. Scheme of the Lingual Artery (Coloured}, 60 33. Scheme of Occipital and Posterior Auricular Arteries (Coloured}, 61 34. The Common Carotid, the External and Internal Carotid, and the Subclavian Arteries of the Right Side and Their Branches (Coloured}, 62 35. Anterior and Lateral Cervical Muscles, 64 36. Scheme for Head and Upper Extremity, After Potter 65 37. The Subclavian Vessels (Coloured}, 66 38. The Collateral Circulation after Ligature of the Common Carotid and Subclavian Arteries (Coloured}, 67 39. Scheme of the Superior Intercostal Artery (Coloured}, 68 40. Scheme of the Vertebral Artery (Coloured}, 69 41. Scheme of the Cervical Plexus, After Potter 75 42. Scheme of the Brachial Plexus, After Potter 76 43. Superficial Branches of the Cervical Plexus (Coloured}, . . . . After Hirschfeld and Leveille 78 44. Side View of the Tongue with its Muscles, 80 45- Side of the Face and Mouth Cavity, showing the Three Salivary Glands, 8l 46. Transverse Section through the Left Half of the Tongue, 82 47. Scheme of the Right Lingual Artery (Coloured}, Walshatn 83 48. Side View of the Muscles of the Tongue, 83 49. The Pterygoid Muscles, 84 50. Distribution of the Mandibular Division of the Trigeminal Nerve, Henle 84 51. Scheme of Internal Maxillary Artery (Colotired}, 86 52. The Temporal Muscle, 88 53. Scheme of the Distribution of the Fifth Cranial or Trigeminal Nerve, ..... After Potter 89 54. Muscles, Vessels, and Nerves of the Tongue, 90 55- The Maxillary Nerve Seen from Without (Colotired} Beaunis 91 56. The Deeper Layer of the Muscles of the Face and Neck, 94 57. The Pterygoid Muscles, 95 58. Temporo-mandibular Articulation. Schematic, 96 vii viii LIST OF ILLUSTRATIONS. 59. Temporo-mandibular Articulation. Schematic, 97 60. Temporo-mandibular Articulation. Schematic, 97 61. Distribution of the Pneumogastric Nerve Viewed from Behind (Coloured), .... Krause loo 62. The Muscles of the Pharynx, . 101 63. The Muscles of the Pharynx, from Gould's Illustrated Medical Dictionary 102 64. Median Section of Mouth, Pharynx, and Larynx, 103 From Gould's Illustrated Medical Dictionary 65. View of Muscles of Soft Palate, as Seen from Within the Pharynx, . Modified from Bourgery 104 66. The Muscles of the Front of the Neck 105 67. Front View of the Cartilages of the Larynx, Modified from Bourgery and Jacob 106 68. Back View of the Cricoid and Arytenoid Cartilages ( Coloured ), 106 Modified from Bourgery and Jacob 69. Posterior View of Thyroid Cartilage with Epiglottis, 107 70. Front View of the Cricoid and Arytenoid Cartilages (Coloured], 107 Modified from Bourgery and Jacob 71. Nerves of the Larynx. (Posterior view.) (Coloured], 108 72. Side View of the Muscles and Ligaments of the Larynx (Coloured), 109 73. The Posterior Nares, 112 74. Section showing Bony and Cartilaginous Septum, 112 75. Nerves of the Nasal Cavity (Coloured], 113 76. Transverse Section Passing through the Nasal Fossae and Antra at the Posterior Extremity of the Middle Turbinal Bone, 114 77. Section of the Nose, showing the Turbinal Bones and Meatuses, with the Openings in Dotted Outline "5 78. The Left Maxilla. (Inner view.), 116 79. The Left Maxilla. (Outer view.), 117 80. A Section of the Skull, showing the Inner Wall of the Orbit, the Base of the Antrum, and the Spheno-maxillary Fossa, 118- 81. The Skull in Sagittal Section, 121 82. The Cranium Opened to Show the Falx Cerebri, the Tentorium Cerebelli, and the Places where the Cranial Nerves Pierce the Dura Mater (Coloured], Sappey 122 83. Coronal Section of the Head Passing through the Mastoid Process 123 84. Schematic, 124 85. Coronal Section through the Great Longitudinal Fissure, showing the Meninges, 1^5 Key and Retzius 86. The Venous Sinuses (Coloured} 127 87. Schematic, . 129 88. Relation of the Various Structures Passing through the Cavernous Sinus, 129 89. Ear and Tympanum, From Gould's Illustrated Medical Dictionary 133 90. Scheme of Facial Nerve Communicating with Fifth Cranial Nerve, After Potter 134 91. The Arteries of the Brain (Coloured}, 136 92. Surface Origin of the Cranial Nerves (Coloured}, After Allen Thomson. Qiiain 93. Tendo Oculi and Tarsal Cartilages, 14 94. Relations of the Eye and the Lachrymal Excretory Apparatus, 14 From Gould's Illustrated Medical Dictionarv 95. Schematic Representation to Show Relation of Periosteum to Tarsal Cartilages and Tarsal Ligaments, I4 1 96. View of Left Orbit from Above, showing the Ocular Muscles, . From Hirschfeld and Lernlle 142 97. Muscles of the Eye From Gould's Illustrated Medical Dictionary 142 98. Nerves of the Orbit, from the Outer Side (Coloured), 143 From Sappey, after Hirschfeld and Leveille 99. Left Eyeball Seen in its Normal Position in the Orbit, with View of the Ocular Muscles, . . 144 After Merkel, modified 100. Muscles of the Eye. Tendon or Ligament of Zinn, 144 From Gould's Illustrated Medical Dictionary 101. Diagrammatic Representation of Origins of Ocular Muscles at the Apex of the Right Orbit, 145 After Schwalbe, slightly altered 102. Vertical Section through the Eyeball and Orbit in the Direction of the Orbital Axis, with Closed Eyelids (Coloured}, ', . . . After Schwalbe, modified 146 103. The Ophthalmic Artery and Vein (Coloured) 14 104. Lachrymal Apparatus, After Schwalbe 147 105. Superficial Veins and Lymphatics of the Forearm and Arm (Coloured}, 153 106. Distribution of Cutaneous Nerves on the Anterior and Posterior Aspects of the Superior Ex- tremity 154 107. Diagram of the Great Palmar Bursa, '55 108. The Left Hand. (Dorsal surface.) (Coloured}, 156 109. The Left Hand. (Palmar surface.) (Coloured}, 157 no. The Superficial Muscles of the Palm of the Hand, 158 111. Superficial Nerves of the Palm (Coloured}, Ellis 159 112. The Deeper Muscles of the Palm of the Hand, 160 113. Anastomoses and Distribution of the Arteries of the Hand (Coloured) 161 114. The Pronator Quad rat us and Deep View of the Palm, 163 115. The Palmar Interossei, 164 LIST OF ILLUSTRATIONS. ix FK... PAGE 116. Anastomoses and Distribution of the Arteries of the Hand (Coloured], 165 117. The Arteries of the Forearm with the Deep Palmar Arch (Coloured'], 172 118. The Bend of the Elbow with the Superficial Veins (Coloured ), 173 119. The Brachial Artery at the Bend of the Elbow (Coloured], 174 120. Front of the Forearm : First Layer of Muscles, 175 121. Superficial Muscles of Palmar Aspect of Forearm, 176 From Gould'' 's Illustrated Medical Dictionary 122. Front of the Forearm : Second Layer of Muscles, 177 123. The Lower Part of the Axillary, the Brachial, and the Radial and Ulnar Arteries (Coloured}, 178 124. The Left Ulna and Radius. (Antero-internal view.) (Coloured), 179 125. Front of the Forearm: Third Layer of Muscles, 180 126. Superficial View of the Front of the Upper Arm, 181 127. Deep View of the Front of the Upper Arm, 182 128. Deep Muscles of Palmar Aspect of Forearm, . From Gould' 's Illustrated 'Medical Dictionary 183 129. The Left Humerus with a Supracondyloid Process and some Irregular Muscle Attachments. (Anterior view.) (Coloured), 184 130. The Pectoralis Major and Deltoid, 188 131. The Left Clavicle. (Superior surface.) (Coloured), 188 132. The Clavi-pectoral Fascia, 189 133. To Show Schematically the* Distribution of the Deep Cervical Fascia Above and Below the Clavicle, 190 134. The Left Clavicle. (Inferior surface.) (Coloured), 191 135. Serratus Magnus. The Inner Wall of the Axilla, 192 136. Front View of the Scapular Muscles. The Posterior Wall of the Axilla, 193 137. The Lower Part of the Axillary, the Brachial, and the Radial and Ulnar Arteries (Coloured), 194 138. First and Second Ribs (Coloured), 198 139. The Sternum, 199 140. The Intercostal Muscles, 200 141. The Intercostal Nerves, 201 142. The Muscles Attached to the Back of the Sternum, 202 143. Scheme of the Internal Mammary Artery (Coloured), 203 144. Anterior View of the Lungs: Pericardium, Modified from Bourgery 205 145. Anterior View of the Thorax with Chest Wall Removed, showing the Lungs, 206 Modified front Bonrgery 146. Invagination of Pleura, 207 147. Thymus Gland in a Child at Birth, 209 148. Scheme of the Fcetal Circulation, 210 149. Anterior View of Fcetal Heart, Vessels, and Lungs, 211 150. The Arch of the Aorta, the Thoracic Aorta, and the Abdominal Aorta, with the Superior and Inferior Vena Cava and the Innominate and Azygos Veins (Coloured), 212 151. The Heart and Great Vessels, with the Root of the Lungs, Seen from Behind (Coloured), . 214 152. The Sympathetic System of Nerves, After Potter 215 153. The Arch of the Aorta, with the Pulmonary Artery and Chief Branches of the Aorta (Coloured), 217 154. Anterior View of the Right Chambers of the Heart, with the Great Vessels, 219 155- I he Heart, with the Arch of the Aorta, the Pulmonary Artery, the Ductus Arteriosus, and the Vessels Concerned in the F(etal Circulation (Coloured), 220 156. Anterior View of the Heart, showing its Arteries and Veins (Coloured), 222 157. Posterior View of the Heart, showing its Arteries and Veins (Coloured), 223 158. Cutaneous Nerves of the Thorax and Abdomen, Viewed from the Side, .... After Hcnle 226 159. External Oblique and Ilio-tibial Band, 227 160. The Pectoralis Minor, Obliquus Internus, Pyramidalis, and Rectus Abdominis, 228 161. Obliquus Externus and Fascia Lata, 229 162. Transversalis Abdominis and Sheath of Rectus, 230 163. Internal Oblique and Transversalis Abdominis Muscles, 232 From Gould's Illustrated Medical Dictionary 164. Dissection of the Lower Part of the Abdominal Wall from Within, the Peritoneum having been Removed, , . Wood 235 165. Irregularities of the Obturator Artery, After Gray 237 166. Vessels of the Small Intestine, 238 167. Showing Partial and Complete Investment of Organs by Peritoneum, 239 168. Showing Retro-peritoneal Locality, 239 169. Showing Aorta and Primitive Mesentery, 240 170. Showing Loss of Endothelium at Contact Point of Visceral and Parietal Peritoneum, .... 240 171. Showing Simple Visceral and Parietal Layers of Peritoneum with Cavity Between Them, . . 241 172. Diagram of the Primitive Alimentary Canal, 243 173. Diagrams showing (A) the Formation of the Great Omentum, and (E) the Rotation of the Intestinal Canal, 244 174. The Cceliac Artery and its Branches (Coloured), 247 175. The Viscera as Seen on Fully Opening the Abdomen without Disarrangement of the Internal Parts, After Sarazin 247 176. The Viscera of the Foetus, Riidinger 249 177. Relation of Structures at and below the Transverse Fissure, Thane 251 x L/ST OF ILLUSTRATIONS. FIG. ru.K 178. The Inferior Surface of the Liver, 254 179. Posterior Surface of the Liver, 254 180. The Superior Mesenteric Artery and Vein (Coloured ), 257 181. The Inferior Mesenteric Artery and Vein (Coloured), 258 182. Diagram showing Anterior Relations of Kidneys and Suprarenal Bodies 259 183. The Abdominal Aorta and its Branches, with the Inferior Vena Cava and its Tributaries, . . 260 184. The Sympathetic System of Nerves, After Potter 262 185. The Sympathetic System of Nerves, After Potter 264 l8b. Showing Schematically a Sensory Reflex Circuit, 269 187. Showing Schematically a Motor Reflex Circuit, 270 188. To Show Relation of Abdominal Sympathetic Nerves to (l) Solar Plexus, and (2) to the Ganglion at the Root of the Artery, 271 189. Lumbar Portion of the Gangliated Cord, with the Solar and Hypogastric Plexuses (Coloured), 272 (After ilenle) 190. Branches of the Lumbar and Sacral Plexus, Viewed from Before (Coloured}, 276 After Hirschfeld and Leveillc 191. Side View of Pelvis and Upper Third of Thigh, with the External Iliac, Internal Iliac, and Femoral Arteries and their Branches (Coloured), 277 192. Muscles of the Floor of the Pelvis . . 278 193. Diagram of the Lumbar and Sacral Plexuses, Modified from Paterson 280 194. A Dissection of the Lumbar and Sacral Plexuses, from Behind (Coloured), 281 195. Diaphragm, 286 196. The Left Hip-bone. (Internal surface.) (Coloured), 287 197. Psoas, Iliacus, and Quadratus Lumborum, 288 198. Arrangements of Lumbar Aponeurosis at Level of Third Lumbar Vertebra, 289 199. The Sacrum and Coccyx. (Anterior view.) (Coloured), 290 200. Muscles of the Floor of the Pelvis, 290 201. The Broad Ligament and its Contents, seen from the Front, After Sappey 291 202. Representing Schematically the Relation of the Ureter to the Broad Ligament of the Uterus, 292 203. Frontal Section of the Virgin Uterus, After Sappey 292 204. Scheme of the Ovarian and Uterine and Vaginal Arteries (Coloured),- 293 205. The P'emale Organs of Generation, Modified from Sappey 293 206. Sagittal Section of the Virgin Uterus, ' After Sappey 294 207. The Left Tibia and Fibula. (Anterior view.) (Coloured), 300 208. The Left Tibia and Fibula. (Posterior view.) (Coloured), 301 209. Distribution of Cutaneous Nerves on the Anterior Aspect of the Inferior Extremity, .... 303 210. The Superficial Veins and Lymphatics of the Lower Limb (Coloured), 304 211. Superficial Dissection of the Front of the Thigh, Hirschfeld and Lerei/le 305 212. The Femoral Ring and Saphenous Opening, After Holden 309 213. The Muscles of the Front of the Leg, 311 214. The Anterior Tibial Artery, Dorsal Artery of the Foot, and Anterior Peroneal' Artery, and their Branches (Coloured), 312 215. The Left Foot. (Dorsal surface.) (Coloitred), 313 216. The Left Tibia and Fibula. (Anterior View.) (Coloured), 314 217. Branches of the External Popliteal Nerve (Coloured), 3*6 218. Muscles of the Front of the Thigh, 317 219. Anterior Crural and Obturator Nerves, 318 220. The Deep Muscles of the Front of the Thigh, 319 221. Pectineus and Adductor Longus, 3 2 222. Adductor Brevis and Adductor Magnus, 320 223. The Femoral Artery in Scarpa's Triangle (Coloured), 3 22 224. Obliquus Externus and Fascia Lata, 323 225. Muscles of the Anterior Aspect of the Body, . From Gould 1 s Illusti ated Medical Dictionary 324 226. The Left Hip-bone. (Posterior view.) (Coloured) 325 227. The Left Femur. (Posterior view.) (Coloured), 326 228. The Left Femur. (Anterior view.) (Coloured), 327 229. The Male Perineum (Coloured), Modified from Hirschfeld unif Lcreill,'- 331 230. The Arteries of the Perineum (Coloured), 332 231. Transverse Section through the Body of the Penis (Coloured), 333 232. The Male Urethra, cleft dorsally t<> Show Ventral Mucous Wall, .... 335 233. Diagram of the Superficial and 1 )eep Triangular Ligaments (Coloured), 330 234. Muscle of Guthrie 3.^7 235. Muscle of Guthrie and Wilson, 337 236. V:isa I h-feientia and Vesiculae Seminales, (fter Sappey 338 237. Diagrammatic Representation of the Peiineal Structures in the Female 341 238. External Genitals of the Virgin, with Diaphragmatic Hymen, -{flcr Sappey 342 239. Sri lion of the Female Pelvis, ... After Henle 343 240. The Left Scapula. (Dorsal surface.) (Coloured), 345 241. Distribution of Cutaneous Nerves on the Anterior and Posterior Aspects of the Superior Y.\ tremity, 34^ 242. A Dissection of the Cutaneous Nerves on the Dorsal Aspect of the Hand and Fingers H.St.J.B. 347 243. Muscles of the Radial Side and the Back of the Forearm 349 LIST OF ILLUSTRATIONS, xi FIG. PAGE 244. Tendons upon the Dorsum of the Hand, 350 245. The Deep Layer of the Back of the Forearm, 351 246. The Left Ulna and Radius. (Postero-external view.) (Coloured), 352 247. The Back of the Forearm, with the Posterior Interosseous Artery and Branches of the Radial at the Back of the Wrist (Coloured), 353 248. The Dorsal Interossei, 354 249. The Posterior Circumflex Artery (Coloured), 356 250. First Layer of the Muscles of the Back, 357 251. Back View of the Scapular Muscles and Triceps, 358 252. Posterior View of the Shoulder-joint, showing also the Acromio-clavicular Joint and the Proper Ligaments of the Scapula, 359 253. Triceps Brachialis, Posterior Aspect, from Gould's Illustrated Medical Dictionary 360 254. The Dorsal Scapular Artery (Coloured), 361 255. Distribution of Cutaneous Nerves on the Posterior Aspect of the Inferior Extremity 367 256. Superficial Muscles of the Back of the Thigh and Leg, 368 257. Gluteus Maximus Muscle, From Gould ' s Illustratea Medical Dictionary 370 258. A Dissection of the Nerves in the Gluteal Region (Coloured), 371 259. The External Rotators and the Hamstring Muscles, 373 260. Deep Dissection of the Gluteal Region, 374 261. Horizontal Section of the Knee-joint. (One-half.), 375 262. Short Head of Biceps and Semimembranosus, . From Gould's Illustrated Medical Dictionary 376 263. Long Head of Biceps and Semitendinosus, . . From Gould's Illustrated Medical Dictionary 376 264. Deep View of the Popliteal Space, Hirschfeld and Leveille 378 265. The Deep Muscles of the Hack of the Leg 379 266. Relations of the Popliteal Artery to Bones and Muscles (Coloured,) 380 267. The Left Tibia and Fibula. (Posterior view.) (Coloured), 381 268. The Left Foot. (Plantar surface.) (Coloured), 382 269. Muscles of the Leg, External Aspect, .... Front Gould's Illustrated Medical Dictionary 383 270. Second Layer of the Muscles of the Sole, 385 271. First Layer of the Muscles of the Sole, 386 272. Superficial Nerves in the Sole of the Foot (Coloured), Ellis 387 273. The Plantar Arteries (Coloured), 388 274. Third Layer of the Muscles of the Sole, 389 275. Fourth Layer of the Muscles of the Sole, 591 276. Horizontal Section through the Intervertebral Disc and Ribs, 396 277. Showing the Anterior Common Ligament of the Spine, and the Connection of the Ribs with the Vertebne, 396 278. The Occipital. (External view.) (Coloured), 397 279. Distribution of the Posterior Primary Divisions of the Spinal Nerves, .... 399 280. First Layer of Muscles of the Back, 401 281. The Levator Anguli Scapulas and Rhomboidei, 402 282. The Third and Fourth Layers of the Muscles of the Back, ... 403 283. The Fifth Layer of the Muscles of the Back, 404 284. The Fifth Layer of the Muscles of the Back, after Separating the Outer and Middle Divisions, 406 285. The Sixth Layer of the Muscles of the Back, 408 286. First Cranial Nerve, Olfactory Afttr Potter 412 287. Second Cranial Nerve, Optic, ..',...... After Potter 412 288. Third Cranial Nerve, Motor Oculi, After Potter 413 289. Fourth Cranial Nerve, Trochlear, After Potter 413 290. Fifth Cranial Nerve After Potter 414 291. Seventh Cranial Nerve, Facial, or Portia Dura, After Potter 415 292. Box Illustration of Seventh Cranial Nerve in Relation to the Middle Ear or Tympanum, . . 416 293. Eighth Pair of Cranial Nerves, After Potter 418 294. Vertical Section through the Condyle of Jaw to Show the Two Synovial Sacs and the Inter- articular Fibro-cartilage, . 425 295. External View of Temporo mandibular Joint, 427 296. Internal View of Temporo-mandibular Joint, 427 297. Outer View of the Shoulder-joint, showing the Coraco-humeral and Transverse Humeral Ligaments, 428 298. Posterior View of the Shoulder-joint, showing also the Acromio-clavicular Joint and the Proper Ligaments of the Scapula, 429 299. Anterior View of Shoulder, showing also Coraco-clavicular and Coraco-acromial Ligaments, 430 300. Anterior View of Sterno-clavicular Joint, 431 301. Orbicular Ligament, 433 302. External View of the Elbow-joint, 433 303. Internal View of the Elbow-joint, 434 304. Anterior View of Wrist, 434 305. Posterior View of Wrist 435 306. Synovial Membranes of Wrist, Hnnd, and Fingers, 436 307. Posterior View of the Capsule of the Hip-joint, 438 308. Anterior View of the Capsule of the Hip-joint, 439 309. Hip-joint after Dividing the Capsular Ligament and Disarticulating the Femur, 441 310. Anterior View of the Internal Ligaments of the Knee-joint, 441 xii LIST OF ILLUSTRATIONS. FIG. PAGE 311. Posterior View of the Knee-joint, 442 312. Structures Lying on the Head of the Tibia. (Right knee.), 442 313. Anterior View of the Knee-joint, showing the Synovial Ligaments, 443 314. The Left Foot. (Plantar surface.) (Coloured), 446 315. The Left Foot. ( Dorsal surface. ) (Coloured), 447 316. Section to Show^ the Synovial Cavities of the Foot, 448 317. External View of the Ligaments of the Foot and Ankle, 449 318. Inner View of the Ankle and the Tarsus, showing the Groove for the Tendon of the Tibialis Posticus, 450 319. Ligaments of the Sole of the Left Foot, 450 320. Ligaments seen from the Back of the Ankle-joint, 452 321. Right Innominate Bone, External Aspect, . .From Gould 's Illustrated Medical Dictionary 453 322. Pelvis, Antero-superior View, Superior Strait, . From Gould 's Illustrated Medical Dictionary 453 323. Femur, Posterior Aspect, From Gould'' s Illustrated Medical Dictionary 454 324. Anterior View of the Symphysis Pubis (Female, showing Greater Width between the Bones), 455 325. Posterior View of the Symphysis Pubis, showing the Backward Projection of the Symphysial Substance and the Decussation of the Fibres from the Inferior Pubic Ligament, 455 326. Anterior View of the Symphysis Pubis (Male) showing Decussation of the Fibres of the Anterior Ligament, 455 327. Anterior View of the Pelvis, 456 328. Sacro-sciatic Ligaments. (Posterior view.), 457 329. Vertical Antero-posterior Section of the Pelvis, 458 330. Coccyx, Anterior Aspect, From Gould' 1 s Illustrated Medical Dictionarv 459 331. Vertebral Column, Lateral Aspect, From Gould's Illustrated Medical Dictionary 459 332. Posterior Common Ligament of the Spine. (Thoracic region.), 460 333- Ligamenta Subflava in the Lumbar Region, 461 334. Morphology of the Transverse and Articular Processes, 462 335. The Interspinous and Supraspinous Ligaments in the Lumbar Region, 463 336. Vertical Transverse Section of the Spinal Column and the Occipital Bone to Show Ligaments, 464 337. Seventh Cervical Vertebra, Postero- superior View ; Dorsal Vertebra, Antero-superior View ; First Dorsal Vertebra, Lateral View ; Eleventh Dorsal Vertebra, Lateral View ; Twelfth Dorsal Vertebra, Lateral View, From Gould' 1 s Illustrated Medical Dictionary 465 338. Occipital Bone, Postero-inferior View, . . . . From Gould' 1 s Illustrated Medical Dictionary 465 339. Anterior View of the Upper End of the Spine, 466 340. Showing the Anterior Common Ligament of the Spine, and the Connection of the Ribs with the Vertebrae 466 341. Vertical Antero-posterior Section of Spinal Column through Median Line, showing Ligaments, 467 342. The Superficial Layer of the Posterior Common Vertebral Ligament has been Removed to Show its Deep or Short Fibres, 468 343. Ribs of Left Side, Posterior Aspect, From Gould 's Illustrated Medical Dictionary 469 344. Thorax, Anterior View, From Gould's Illustrated Medical Dictionary 469 345. The Capsular Ligaments of the Costo-vertebral Joints, 470 346. Horizontal Section through the Intervertebral Disc and Ribs, 471 347. The Sternum, 47 2 PRACTICAL ANATOMY. FUNDAMENTAL PRINCIPLES OF ANATOMY. In the following introductory pages will be found some rules and observations on anatomical study which the student must learn, if he would become master of dissecting-room technique. Under the above heading are considered : 1. Anatomical nomenclature. 2. Anatomical tissues applied. 3. Functions of periosteum. 4. Eminences and depressions of bone. 5. Anatomical weak points. 6. Anatomical visceral roots. 7. Anatomical antagonism in muscles and nerves. 8. Shape of muscle an index to the nerve-supply. 9. Hilton's law regarding articular nerves. 10. Non-apposition of anatomical structures. 1 1. Anatomical sheaths ; rationale of their formation. 12. Dissection defined. 13. Fanciful names for muscles. 14. Sphincters and orbiculars distinguished. 15. Geometrical usage in anatomy. 1 6. Substantive adjectives : use of. 17. Law of projectiles : its application to grooves. 1 8. Application of law of projectiles to reflex pain. 19. Fasciae, superficial and deep. 20. Aponeuroses : varieties of. 21. Origin and insertion of muscle. 22. Synovial membranes. 23. Serous and mucous membranes. 24. Anatomical fibrous arches. ANATOMICAL NOMENCLATURE. This chapter is intended to explain in advance some of the features of anatomical nomenclature, a knowledge of which will facilitate an understanding of what is seen, read, and heard. Anatomical nomenclature is the technical language of anatomy. Chemistry, music, law, all the arts and sciences, have their nomenclature. One of the surest indications of thorough system in any science is the nomenclature of that science, if, indeed, a department can be called scientific without a nomenclature. 9 io PRACTICAL ANATOMY. Compound words are used to express the collective sense arising from anatomical union, conjunction, and relation. Words of this class are met many times daily, not only in anatomy, but in every branch of the medical sciences. Sterno-hyoid, omo-hyoid, musculo-aponeurotic, temporo-mandibular, express relations in anatomy that are thoroughly understood by the physician. The principle in compound words is clearly in the nature of a copartner- ship. In the expression, radio-ulnar articulation, radius and ulna are both concerned in the formation of this joint ; each bone has an anatomical interest in the joint, hence a physiological responsibility. The name of an articulation, then, to represent fully the copartnership, must include all the parties to the contract. The number of partners must be two ; it may be any number : (i) Sterno-cleido-mastoid ; (2)fronto-malo-spheno-ethmo-lachrymo-maxillo-nasal articulation. RULE FOR WRITING MINIMAL COMPOUND WORDS. Place the shorter word first in the ablative, o ; the larger word second, in some euphonious adjective ; connect the two words by a hyphen. The rule for writing maximal compound words is the same. Here the shortest word is placed first ; it and all succeeding words end in o except the last. Exceptions to the rule are (i) to indicate direction of motion ; (2) to conform to national or individual ideas of euphony. We may express the direction taken by a missile passing from the radial to the ulnar side thus : radio-ulnarly, or the opposite by ulno-radially. In many cases euphony demands the larger word first. Where exceptions are as important as these, they seem to acquire the dignity of law ; hence remember in writing compound words either word may be placed first. Anatomical Opposites in Location or Function. The fundamental idea in each is antagonism ; of location in the former, of function in the latter. An under- standing of one opposite implies the necessity of the other's presence : anterior surface of the scapula is positive evidence of the existence of a posterior surface of the scapula. The principle is sometimes abused e. g., internal iliac muscle is referred to in some texts ; there is no external iliac muscle ; etc. These redun- dancies, while undesirable, since they are misleading, are nevertheless tolerated in some good works on anatomy by a sort of license that characterizes the unique redundancy in legal and scientific phraseology. Musculus flexor carpi radialis and musculus extensor carpi radialis are anatomical examples of ana- tomical structures opposite in function. Remember, too, that structures opposite in function are usually also opposites in point of location on the part of the body in which found. EXAMPLES OF COMMON OPPOSITES. Superior extremity. Inferior extremity. Anterior surface. Posterior surface. Ventral mesentery. Dorsal mesentery. Central organ. Peripheral organ. Somatic nerves. Sympathetic nerve?. Proximal end. Distal end. Tendinous origin. Tendinous insertion. Flexor muscles. Extensor muscles. Pronator agents. Supinator agents. Greater trochanter. Lesser trochanter. Base of lung. Apex of lung. Levator muscle. Depressor muscle. Gluteus maximus. Gluteus minimus. Pectoralis major. Pectoralis minor. Peroneus longus. Peroneus brevis. Colica dextra. Colica sinistra. Centripetal vessels. Centrifugal vessels. Compact tissue. Cancellous tissue. Longitudinal axis. Transverse axis. FUNDAMENTAL PRINCIPLES OF ANA TOMY. 1 1 CLASSICAL WORDS IN COMMON USE IN ANATOMY. A'anu'. Gen. Sing. Plural. Gen. Plural. English. Fascia, ... se, .... Fasciae. Fasciarum. Sash. Glandula, . . ae, . . . . Glandulas. Glandularum. Gland. Vena, . . . ae Venae. Venarum. Vein. Artena, . . . ae Arteriae. Arteriarum. Artery. Cartilage, . . inis, . . . Cartilagines. Cartilaginum. Cartilage. Chondrum, . i, .... Chondra. Chondrium. Cartilage. Tendo, ... is, .... Tendines. Tendinium. Tendon. Musculus, . i Musculi. Musculorum. Muscle. Nervus, . . i Nervi. Nervorum. Nerve. Vas is, .... Vasa. Vasorum. Vessel. Os, sis, . . . Ossa. Ossium. Bone. Os ris, . . . Ores. Orium. Mouth. Aponeurosis, is, .... Aponeuroses. Aponeurosium. Band. Costa, ... ae, .... Costae. Costarum. Rib. Viscus, ... us, ... Viscera. Organ. Pons, . . . tis, . . . Pontes. Pentium. Bridge. Trochlea, . . ae Trochleae. Trocharum. Pulley. Gaster, Stomach. Intestinum, . i Intestini. Intestinorum. Intestine. Many adjectives are in use, as magnus, longus, brevis, latus, profundus, sub- limis, orbicularis ; they are declined and used as the nature of the case would indicate. Rationale of Naming of Certain Muscles. It is important that the student should, early in his course of dissection, understand why certain muscles are named as they are named in the books. In fact, the student should have a knowledge of the principle involved in this part of the nomenclature. To one unfamiliar with this principle the names tibialis antictts, pronator quadratics, extensor minimi, may seem perfect and complete designations. The impression, however, is erroneous, as the above terms are incomplete. In other words, the terms above given are only abbreviations, and are properly used when the manner by which usage sanctions them is understood. The principle is this : The complete technical name of a muscle contemplates : (i) The structure ; (2) the structure in the capacity of an agent ; (3) an agent of something ; (4) an agent adjectively qualified in such a manner as to distinguish it from others of a syner- gistic class. STRUCTURE. AGENT. AGENT OF WHAT. DESCRIPTIVE ADJECTIVES. Mttsculus flexor carpi Musculus flexor carpi Musculus flexor cubiti Musculus extensor carpi Musculus extensor carpi Musculus extensor digitorum Musculus extensor digiti Musculus levator labii radialis ulnaris bicipitalis radialis radialis communis minimi superioris longior brevior We unconsciously acquire a habit of using the abbreviated name, and this explains in part the lamentable fact that so many students leave school with a memory well stored with words words numerous, ponderous, classical words which, by virtue of their abbreviational arrangement, leave on the memory no notion of the physiological function of the muscle. At times the habit of thinking of names of muscles almost makes us fail to recognize the full name. The following table will illustrate this point : ANATOMICAL NAME. TECHNICAL NAME. Tibialis anticus Musculus flexor tarsi tibialis anticus. Tibialis posticus Musculus extensor tarsi tibialis posticus. Peroneus longus Musculus extensor tarsi peroneus longus. 12 PRACTICAL ANATOMY. ANATOMICAL NAME. TECHNICAL NAME. Peroneus brevis, Musculus extensor tarsi peroneus brevis. Peroneus tertius Musculus flexor tarsi peroneus tertius. Triceps, . . . ' Musculus extensor cubiti tricipitalis. Biceps, Musculus flexor cubiti bicipitalis. Supinator longus Musculus supinator brachio-radialis longior. Supinator brevis Musculus supinator brachio-radialis brevior. Pronator quadratus, Musculus pronator radii quadratus. Grammatical Xotc. In constructing technical names of muscles, note (i) the agent, and (2) the descriptive adjectives are in apposition with musculus. The thing or part of which another part is the agent is in the genitive case. The student will note that adjectives are mainly of the first and second declensions, some of the third ; sublimis belongs to the third, so do not write it sublimits. TECHNICAL USE OF PREPOSITIONS. An almost unlimited number of words designative of relation are formed by the judicious use of classical prepositions. It will be noted that these words, while governing case in the language from which they are taken, cease to be prepositional in anatomical nomenclature in the great majority of instances. Still they may be so used; and upon the distinction now about to be made depends the proper construction of the new words which come into being by thousands by the simple process of incorporating classical prepositions. In the following cases the words are used prepositionally, and written thus : 1. Iter e tertio ad quartum ventriculum. 2. Processus e cerebello ad testes. 3. Portio inter duram et mollem. 4. Musculus accessorius ad flexorem, etc. 5. Musculus accessorius ad musculum, etc. In the majority of cases the word is absorbed to form a new word, bearing a close relation in location, and not in structure ; to the word into which it was incor- porated. The following examples will illustrate the process of forming new- words and their proper writing : Subcostal, intermaxillary, infraorbital, supra- orbital, intraabdominal, extrauterine. Remember, then, this rule for writing these words : Where they are prepositionally used, the preposition governs the accusative ; where they are used in a corporate capacity, the preposition and the qualified word, or its adjective representative, are written as one word. Inter is used to express relation between anatomical structures having the same name. Not only does it express relation in this sense, but it also names every structure in the locality : Intercostal space, muscle, fasciae, vessels, and nerves. Intra as intrauterine, intrapelvic, intracranial, intrathoracic, intraabdominal, intratympanic, intramural, intraintestinal, intramuscular, means inside of or in the substance of. Its verbal opposite is extra. Sub implies location under, in the sense of occupying a deeper plane : Sub- cutaneous, subserous, submucous, subperitoneal, subpleural, subsynovial, subcon- junctival. It has no opposite, none being necessary to make descriptions of this nature more definite. Its legitimate field of usefulness in our nomenclature seems to be in expressing relations in the concrete rather than in the abstract. Submucous means a territory under all mucous membrane ; subcutaneous, under the skin everywhere, regardless of location of skin or kind of animal. How such expressions as submuscular, subosseous, or subgastric would shock our conception of the proper use of this word ! Still, such barbarisms as sub- maxillary, submcntal, and sublingual are sanctioned by usage and good usage, too. FUNDAMENTAL PRINCIPLES OF ANATOMY. 13 Supra is limited in its application to a few areas, for the reason that it does not combine well to form euphonious words, and euphony, you will observe, is a potent factor in determining the volume of our anatomical vocabulary. The chief use of the term is in physical diagnosis, where regions requiring no definite limitations are indicated by supra in combination with the name of the locality under consideration : Supraorbital, suprasternal, supraclavicular, suprascapular, suprapubic, supratrochlear, supratrochanteric, supracondylar, supragluteal, supra- hyoid, supraacetabular. Infra is the opposite, but can not with propriety be used in some cases, as infracondylar ridge, since no such ridge exists. Juxta has the specific meaning of one above another with parallelism of parts. Its use is confined to osteology almost wholly, with no good reason. In the vertebral column we have juxtaposition of bodies, transverse, spinous, and articular processes ; juxtaposition of laminae, pedicles, and intervertebral notches. Still, for practical purposes, the biceps and brachialis are in juxtaposition. Usage determines the scope of legitimate nomenclature. Pre, as in preaxial, the opposite of post-axial ; in presystolic ; in pre- vertebral, in speaking of the three great prevertebral gangliated plexuses of the sympathetic nervous system. The use of this word is limited. Peri. The prepositional excellence of anatomical nomenclature seems to culminate in the word now under consideration. For this there is good reason : its euphonious nature combines with everything of an anatomical kind, either in substantive or adjective form, and besides it expresses a relation comprehending all other relations around. Every visible anatomical structure possesses a protective coat or sheath, which surrounds and protects the same. Many of these are expressed by peri in combination, as the following will show : Peri- osteum, perimysium, periuterine, pericardium, peritendineum, peridontium, peri- pulmonum, perichondrium, perineurium, peritoneum, perinaeum, periglottis, periorbita, perivenal, periproctic, peristaltic, perivisceral. In the course of your dissection make a study of each technical word used, and you will soon acquire a habit of thinking in anatomical terms when doing anatomical work. Remember every anatomical region is occupied by structures, and these structures have names and relations. If you learn the principles on which the technical language of anatomy is founded, then you shall have passed the first milestone on your way to a medical education.* THE ANATOMICAL TISSUES. In the dissecting-room you meet normal tissues, as muscle, nerve, and skin, in all their various forms and combinations. It is here you should apply practically those things you have learned in such thorough detail in the histo- logical laboratory. It is true you deal here with these tissues, not with the microscope, but with the unaided eye and the sense of touch. In the laboratory you learned to recognize epithelial tissue in general and special, and you classified the same according to the shape and strata of the cell. Here it is enough for you to remember that the epithelial tissues cover the free surface of the skin and mucous membrane. The Bulky Portion of Your Work is Made Up of Muscles. Of these you learn origin, insertion, relation, nerve-supply, blood-supply, investment, and func- tion. This is gross anatomy. You must also remember histologically that all muscles belong' to the muscular tissues, that the characteristic of these tissues is *The technical terms used in anatomy are chiefly of Latin derivation ; the grammatical construction is purely so. In view of the importance of being familiar with our nomenclature, I would recommend Robinson's Latin Grammar, both for those who have given but little lime to classical study and also for those who wish to review the same. 14 PRACTICAL ANATOMY. contractility, and that muscles occur, (i) in the voluntary form ; (2) the involuntary form. You will be expected to classify each muscle according to the above forms. To aid you in this, the following table is inserted : TABLE SHOWING WHERE INVOLUNTARY MUSCLES ARE FOUND. Character of fibre : Smooth, non-striated. 1. In the alimentary canal (oesophagus, stomach, intestines, large and small), and in the embryological offspring of the duodenum (the common bile duct, the hepatic ducts, the gall-bladder, and the pancreatic duct) and salivary glands. 2. In the genito-urinary tract of the male and female: the muscular part of the vas, the seminal vesicles, Cowper's glands, the corpora spongiosa and cavernosa, and the prostate in the male ; in the uterus, vagina, Fallopian tubes, round and broad ligaments, and in the erectile tissue of the nipple and external genitals of the female. In the bladder, urethra, and all parts of the urethra in botJi male and female. 3. In the trachea, bronchi, and pleura ; in all arteries, veins, and lymphatics ; in the iris, ciliary body, and eyelids ; in the skin of the scrotum ; in the hair follicles and sebaceous glands. 4. You will see later that the territory where you are to locate the involuntary form of muscular tissue coincides with the distribution of the sympathetic nerve, or the nerve of organic life. You Will Find Brain and Nerves. The structural part of these is purely histological ; still, you will be expected to remember that nerve-tissue consists of cells, fibres, and neuroglia, and a connective-tissue framework. You will find nerves, called sympathetic^ supplying the viscera and all others ; the ccrcbro-spinal, supplying the skin, joints, muscles, and organs of special sense. You sJiould remember that all brain and nerve matter belong to the nervous tissues. The connective tissues, in their many forms, will be found everywhere. I wish thus, in advance, to teach you where to find and how to classify the same. All the peristructures mentioned in the chapter on nomenclature are forms of connective tissue. This is the most widely distributed of all the tissues. Your task now is to learn to recognize its forms as you meet them. FORMS OF CONNECTIVE TISSUE You WILL MEET IN THE DISSECTING-ROOM. 1. Mucous Form. This is a clear, jelly-like substance surrounding the umbilical cord. Ligate this and see how easily a thread cuts through the same. This is the jelly of Wharton you will hear about. // is one form of con- nective tissue. 2. Areolar Form. Immediately on removing the skin you will notice the areolar form of connective tissue. It is also called superficial fascia in this locality. It contains a variable amount of fat.. It is called areolar mem- brane in some of the older text-books. On separating one muscle from another, you will see this areolar tissue. Its specific name, in this locality, is intermuscular fascia. 3. Cartilage forms of connective tissue occur in the trachea, larynx, and external ear, where the presence of this tissue gives these structures their strength and elasticity. You will find it completing the space between the ribs and sternum ; you will find it covering the articular surfaces of bone in movable joints. 4. Bone l ; onn. This is coextensive with the osseous skeleton. Every bone, be it long, short, flat, irregular, is connective tissue in this form. Each bone is covered, at its articular surface, when it moves upon another bone, by FUNDAMENTAL PRINCIPLES OF ANATOMY. 15 cartilage : this cartilage is one form of connective tissue. Each bone is covered by periosteum, except at the articular surfaces ; this periosteum is connective tissue. 5. Elastic Form. In the interlaminar ligaments, or ligamenta subflava, you will find a form of connective tissue, yellowish in color, and also dense, elastic, and strong. You will find this as well in the epiglottis. Wherever you find structures possessing (i) elasticity, (2) yellowisJi color, as the aorta and structures above mentioned, they owe these qualities to the elastic form of connective tissue. 6. Adipose Form. You will find this in the superficial fascia or areolar tissue under the skin ; in the great omentum, about the heart, in the iliac region of the pelvis, and in the ischio-rectal fossa. Remember, fat is the adipose form of connective tissue. This tissue represents the great storehouse for potential energy. The student who desires to see the human body in possession of this potential energy will select a fat subject for dissec- tion ; while the student who desires to keep his hands clean will continue to clamor for lean material. If you intend to do surgical operations, remember this : The emaciated patient is seldom operated on. Only those possessing fat and vitality are considered good risks. If you dissect a fat cadaver, then you may expect to see man as he is in health. A lean man is man minus fat not a fair sample. 7. Supporting Form. Dissect any organ, and you will find it covered by a layer of connective tissue, and the parts making up the interior supported by the same. Boil a muscle, and you will see the connective tissue interior. Macerate thoroughly a spleen, and by gentle compression in warm water remove the spleen-pulp, and you will have remaining the connective tisstie of this organ the supporting form of connective tissue. The nerve-cells and nerve-fibres are likewise supported by connective tissue, called neuroglia. 8. Dense Form. This form you will find in tendons and fasciae ; in the cornea and sclera ; in the dense aponeuroses ; in the strong intermuscular septa. QUERY. How can a tissue appear in so many forms ? How is it possible to recognize in the dentine of the teeth and in the areolar tissue between muscles one and the same tissue ? How can you classify bone and the jelly of Wharton in the same category ? EXPLANATION. Each tissue consists of two constituents: (i) Cells, (2) inter- cellular substances. The former are products of the ovum ; the latter of the cells themselves. Each constituent has a certain part to perform in the organ in which the tissue is found. Upon the cell depends the life of the tissue ; upon the inter- cellular substance depend the jelly-like condition, the dentine hardness, the fascial strength, the areolae of intermuscular connective tissue and superficial fascia, the resistance of muscle, the elasticity of the ligamentum subflavum, the cement sub- stance of the epithelial tissues covering the surfaces of the integument and the various mucous membranes. Homely illustration of how a tissue can appear under so many different forms and still remain connective tissue : (i) Permit water to represent the intercellular substance ; (2) permit plastcr-of -Paris to represent the cellular element. As you mix the two, the water will become more and more condensed, until you have finally obtained a substance of bony hardness. The plaster remains plaster, having undergone no changes. In the tissue under consideration the cellular element remains the same : The bone-cell is morphologically the same as the jelly-cell, the tendon-cell, and the fascia-cell. Condensation of the intercellular substance is when the changes have really taken place. In your dissections, when you find fascia, tendon, bone, cartilage, sclera, i6 PR A CTICAL ANA TOM \ '. cornea, peristructures, supporting structures, dentine, and Wharton's jelly, you are to remember, these structures, while widely varying in form, all belong to the greater connective tissue family. RESUME OF ANATOMICAL TISSUES. 1. Muscular tissue, for voluntary and involuntary contraction, upon which depend the aggressive and defensive attitudes of the body, as well as the movements of hollow conduits and certain viscera. 2. Nervous tissue, upon which depends intellection, reception of impression from an environment, and transmission of brain impulses, whether voluntary or involuntary. 3. Connective tissue, on which depends strength, framework, and various invest- ing structures. Common forms specialized are tendon, ligament, capsule, bone, cartilage, dentine, cementum, etc. 4. Epithelial tissue, upon which depend external and internal protection, giving as these tissues do a certain resiliency and stability to the areas which they cover, as the skin and mucous membranes. /$W ofcompressed cotfon reareseafint sheath. Nerve Artery Vein FIG. i. DISPLACEMENT OF COTTON BY GROW- ING PLANTS. Meuro venous septum Neuro arterial septum- . FIG. 2. CONNECTIVE TISSUE DISPLACED BY THE ARTERY, NERVE, AND VEIN; THE CONNECTIVE TISSUE LEFT BETWEEN THE ARTERY AND NERVE AND BETWEEN THE NERVE AND VEIN ARE Two SEPTA. Rationale of the formation of anatomical sheaths, tunics, togas, cap- sules, and all the peristructures referred to and enumerated in the section on anatomical nomenclature. In your dissections you will meet the capsules of glands and the sheaths of vessels. Where an artery, vein, and nerve are in the same sheath, they will be separated from each other by a. septum. In your first dissection you will be dis- appointed at the frail condition of these sheaths at their lack of organization. You will expect to find the sheath of an artery resemble a piece of heavy cloth sewed tightly about the trunk of a tree ; your chagrin will be manifest when you find it resembles more the investment of straw given tender shrubs to pre- vent depredations of rodents in our parks. As any attempt to remove the pro- tective from the tree would result in the complete destruction of the protective, as you removed straw after straw, so, likewise, when you attempt to disen- sheath a vessel you arrive at the vessel, but the sheath has disappeared. Re- member, then, sheaths arc actual entities, and their architecture is adapted to the needs and requirements of the vessel ensheathed, just as the cobweb is architect- urally suited to the needs of the spider; still, when you molest the latter or attempt to dissect the former, the result is the same each almost completely disappears, such is the delicacy of their respective material. FUNDAMENTAL PRINCIPLES OF ANATOMY. 17 For the sake of gaining a conception of the architecture of sheaths and the rationale of their formation by displacement of connective tissue, let the follow- ing explanation be studied : Figure I represents a pot of earth in which various seeds have been planted ; the pot is covered with a layer of absorbent cotton, and exposed to the sun and rain. In time the cotyledons begin to peep through the cotton ; as each becomes larger in diameter, it displaces more cotton. As the cotton displaced by the growing plant may represent the sheath of the plant, so, in like manner, to aid the memory, let us compare a growing artery, bone, muscle, nerve, or gland surrounded by connective tissue (which represents the cotton in the simile of the growing plant) to the plant. The connective tissue would be displaced as the anatomical structure became thicker, and this displaced tissue we call the sheath, capsule, tunic, toga, or peristructure. Now, by the same process account for periosteum, perimysium, perineurium, and all peristructures and capsules. PERIOSTEUM AND ITS FUNCTIONS. Periosteum is the anatomical investment of bone. It covers all the bone except the articular surfaces. It is, as you must demonstrate on your dissection, most intimately adherent to those parts of the bone having the greatest number of irregularities. Its functions are as follows : 1 . Osteogenetic, for it makes bone grow in thickness. 2. Protective, since it hinders progress of contiguous inflammation. 3. Attaclnnental, since it gives attachment to muscles. 4. Nutritive, since it feeds the bone with blood. 5. LAgamentous, since it forms all capsular ligaments. 6. Retentive, since it tends to retain ends of broken bones. EMINENCES, DEPRESSIONS, AND SURFACES OF BONE are determined in shape by the muscles associated therewith, and take the name of the muscle. You are to look on muscular traction as the factor that determines the size of an eminence or the depth of a fossa. In fact, the surfaces of bone are named according to the occupant. In a given bone, as the humerus, name the articular surfaces according to the occupants: (i) Scapular; (2) radial; (3) ulnar. Name the surfaces according to the muscles. The posterior surface has an upper and a lower tricipital surface, corresponding to the humeral heads of the triceps, etc. Bicipital tuberosity, iliac fossa, gluteal ridge, deltoid impression, are instances. You will observe that this rule is not always observed ; still the value of the rule is no less. ANATOMICAL WEAK POINTS comply with two conditions: (i) A location in the continuity of the structure where there is a sudden abrupt cJiange in the direction. (2) A functional area, as between skin and mucous membrane, as where the small intestine opens into the large. In these localities fractures occur in bone, aneurisms in arteries, morbid growths at muco-cutaneous areas. In your dissection bear these areas in mind. Look for intussusceptions at the weak points in the colon ; for fractures at the necks of bones, etc. ANATOMICAL ROOTS are places uncovered by serous membrane, in connection with viscera, where the vessels, nerves, and conduits enter to carry on (i) the functional activity and (2) the nutritive activity of the organ. In your dissection you will give special study to the root-structures of the heart, lung, liver, spleen, kidney, intestine, ovary, testicle, etc. The functional activity is represented by i8 PRACTICAL ANATOMY. what the organ does for the body in general ; the nutritive activity by what the organ does for its own nutrition. The nutrient artery to organs is accompanied by sympathetic nerves, which regulate the supply of blood each organ shall receive. ANATOMICAL ANTAGONISM IN MUSCLES necessitates a consequent antagonism in the nerves that supply these muscles, hence you will understand the meaning of flexor, extensor, abductor, and adductor nerves. The very nature of logical antagonism implies a degree of equality in length, weight, strength, and vantage for origin and insertion. At the hip, flexors, extensors, abductors, and adductors are seen. The antagonistic nerves are the anterior crural, the great sciatic, the obturator, and the gluteal. SHAPE OF MUSCLES AN INDEX TO THE PLACE WHERE THE MUSCLE RECEIVES ITS NERVE-SUPPLY. I desire you to study carefully the following drawings, and in your dissection you must faithfully determine the general shape of the muscle and trace out the nerve thereto. i. Triangular Muscles. The pectorales major and minor, the supra- and infra - spinati, the subscapularis, the deltoid, the gluteals, the pyriformis, and the obturators are examples ; take their nerve-supply near the apex. FIG. 3. TRIANGULAR. FIG. 4. QUADRANGULAR. FIG. 5. FUSIFORM. FIG. 6. Ci.ri;i:i i>. 2. Quadrate Muscles. The pronator quadratus, the brachialis anticus, and multifidus spinae are good examples ; take their nerve-supply near the centre. 3. Fusiform Muscles. Take their nerve-supply near the middle. This, as the biceps, is the same as No. 2, compressed at the ends. 4. Clubbed Muscles. This includes a large number, as those taking origin from the outer and inner humeral condyles take their nerve-supply early. In your work notice how very early the median gives off branches to supply muscles of this type. 5. Scrrati muscles and those arising by more or less pronounced digitations, as the serrati superior and inferior posticus, the diaphragm and the planiform muscles of the abdominal walls, seem to conform to the type of triangu- lar muscles, taking their nerve-supply near the apices of the digitate origins ; still, if the nerves are traced out, they will be found to approach the centre and conform to the quadrate type. Remember, this tracing out of nerves belongs to macroscopic anatomy. To gain an idea of the manner in which the ultimate tissue is innervated, you must study up motorial end plates in physiology and histology. The only object in FUNDAMENTAL PRINCIPLES OF ANATOMY. 19 introducing the subject of shape of a muscle as an index to the nerve-supply entrance is to impress the necessity of tracing out, as far as possible, in your dis- section the branches of the nerves ; possibly the scheme introduced may aid the memory. HILTON'S LAW : Nerve trunks that supply muscles that move a joint supply the joint acted upon with articular brandies ; they also supply the skin, covering the fullest insertion of the muscle. Given, then, the number of antagonistic groups of muscles, you are by this rule able to know the source from which the joint is innervated. ANATOMICAL APPOSITION Is NOWHERE FOUND. In dissecting in any region of the body bear this in mind. Structures arc a fa ays disjunctively connected by a layer of connective tissue. Found between muscles, it is called areolar or inter- muscular connective ; beneath the pleura, subpleural ; beneath the peritoneum, subperitoneal ; beneath mucous membrane, submucous ; beneath the periosteum, subperiosteal. Notice the mortar between the bricks in a wall ; this corresponds to connective tissue in anatomy. DISSECTING Is THE ART OF DIVIDING THE CONNECTIVE TISSUE THAT INTER- VENES BETWEEN ADJACENT STRUCTURES, and the division must be made in such a manner as to do no violence to anatomical compounds, their nerve-supply, their blood-supply, their excretory ducts, their capsules, and their anatomical relations. FANCIFUL NAMES FOR MUSCLES, names founded on some one dominant idea, are frequently met. It is to be regretted that our nomenclature could not have been founded on the idea of function throughout. Note here that the substantive, imtscitlns, while seldom expressed in our texts, is afaars implied. The following will show you some of the names of muscles founded on fanciful ideas, and also the full name as it should appear if founded on the idea of function : FANCIFUL NAMES. PHYSIOLOGICAL NAMES. Sartorius (tailor), .... Musculus extensor tibialis et adductor femoris. Rhomboideus (geom.), . . Musculus levator scapulas rhomboideus. Transversals (direct.), . . Musculus compressor abdominis transversalis. Recius (geom.) Musculus flexor thoracis rectus. Pyramida/is(geom.). . . . Musculus tensor lineas albae pyramidalis. Vastus Externus, .... Musculus extensor vastus externus. External Oblique, .... Musculus compressor abdominis obliquus externus. Serratus Magnus, .... Musculus depressor scapulae serratus magnus. Quadratus Lumborum, . Musculus flexor spins lateralis quadratus lumborum. Latissimus Dorsi, .... Musculus abductor brachii latissimus dorsi. Longissinms Dorsi, . . . Musculus extensor spinse longissimus dorsi. ORBICULAR MUSCLES AND SPHINCTER MUSCLES. You will find the above terms often used interchangeably. The important areas occupied by these muscles make the majority of the same of prime interest to the general surgeon, the genitp-urinaiy specialist, the gynaecologist, the obstetrician, the oculist, the laryngologist, the rectal specialist, the patient. Still, no rational classification of these muscles exists. At the present all orbiculars are sphincters, but not all sphincters are orbiculars, as the following table, founded on usage, will show : SYNONYMOUS USAGE. Orbicularis oris Sphincter oris. Orbicularis ani External sphincter ani. Orbicularis palpebrarum, Sphincter palpebrarum. 2 o PRACTICAL ANATOMY. UNIVERSAL USE OF SPHINCTER. Musculus sphincter vaginae. Musculus sphincter iridis. Musculus sphincter urethrae. Musculus sphincter ilei. Musculus sphincter prostatas. Musculus sphincter gulae. Musculus sphincter cesophagei. Musculus sphincter vesicae. Musculus sphincter laryngis. As the following comparison will show, there is no good reason for confusion of terms and an annoying interchange between orbicular muscles and sphincter muscles. Such is usage. Summary of Differences Between Orbiculars and Sphincters : Orbicular s. 1. The orbiculars are supplied by spinal nerves. 2. The orbiculars are all voluntary. 3. The orbiculars are all dermal muscles. 4. The orbiculars are at muco-cutaneous margins. 5. The orbiculars move rapidly. 6. The orbiculars have parietal blood-supply. 7. The orbiculars are very sensitive to pain. 8. They refer their pain to place of irritation. 9. They report pain foudroyantly. 10. Their nerve-supply is somatic never sympathetic. 11. When lacerated, they repair slowly. 12. They are synonymous for sphincters in three cases only. Sphincters. 1. Sphincters are supplied by the sympathetic. 2. They are all involuntary unstriped fibre. 3. They are not dermals, but viscerals. 4. They are never at muco-cutaneous areas. 5. They always move slowly. 6. They have visceral blood-supply. 7. They are not very sensitive to pain. 8. They refer pain to somatic areas. 9. Their own report of pain is dull and slow. 10. Their nerve-supply is sympathetic. 1 1. When lacerated, they repair readily. The reader is referred to reflexes along somatic and sympathetic lines in the dissection of the female pelvis. TIic ('tents. This would seem to be the most fully grown and fully developed structure among the organs having sphincteric openings. Its proper sphincters aie known as the os intcnntm and os cxternum. It complies in every way to eleven points characteristic of sphincters. GEOMETRICAL TERMS AND FIGURES. You will have much descriptive usage along mathematical lines. This always aids the memory, for it appeals to the basis of every one's education. The axilla has base, apex, angles, and boundaries. The neck has roof, floor, boundaries, and triangles. Tlic nasal fossa has roof, floor, walls, and openings. The orbit has roof, floor, base, apex, angles, and walls. FUNDAMENTAL PRINCIPLES OF ANATOMY. 21 77/6' mouth has roof, floor, sides, openings, dental arches. The tympanum has roof, floor, and four walls. Hunter's canal has roof, floor, boundaries, and extremities. Scarpds triangle has roof, floor, base, apex, boundaries. The iscldo-rcctal fossa has base, apex, walls, sacral and pubic ends. The thorax has apex, base, anterior, posterior, and lateral walls. Inguinal canal has rings, roof, floor, and two walls. Popliteal space has roof, floor, extremities, and boundaries. SUBSTANTIVE ADJECTIVES. These are so frequently used that I wish the student early to learn to supply the missing substantive, not only in the case of muscles, as referred to in nomenclature, but also in the case of arteries, veins, nerves, and lymphatic glands. In social life, after long and thorough acquaintance with your fellows, you justifiably dub your friends John, James, and the like, the while mindful of the full baptismal name ; these liberties of address you would consider improper in addressing comparative strangers. Likewise in anatomy you speak of structures as follows : i. A FRIEND. 2. A STRANGER. The radial artery or vein Arteria radialis or vena radialis. The ulnar artery or vein, Arteria ulnaris or vena ulnaris. The brachial artery or vein, Arteria brachialis or vena brachialis. The femoral artery or vein Arteria femoralis or vena femoralis. The hepatic artery or vein, Arteria hepatica or vena hepatica. The splenic artery or vein, Arteria splenica or vena splenica. The vertebral artery or vein, .... Arteria vertebralis or vena vertebralis. The mesenteric artery or vein, .... Arteria mesenterica or vena mesenterica. The lingual artery or vein Arteria lingualis or vena lingualis. The facial artery or vein, Arteria facialis or vena facialis. Lymphatic Glands. Cervical gland, Glandula lymphatica cervicalis. Mesenteric gland, Glandula lymphatica mesenterica. Inguinal gland, Glandula lymphatica inguinalis. Axillary gland, Glandula lymphatica axillaria. Epitrochlear gland, Glandula lymphatica epitrochlearis. Nerves. Radial, Nervus radialis. Ulnar Nervus ulnaris. Femoral, Nervus femoralis. Lingual, Nervus lingualis. Facial, Nervus facialis. Circumflex Nervus circumflexus. Great sciatic, Nervus sciaticus magnus. Sympathetic, Nervus sympatheticus. Remember, arteries, nerves, veins, lymphatics, and muscles are spoken of, the country over, in the adjective abbreviated form by those who know what they are talking about ; you, however, are not to speak of these structures in the abbreviated form until you are familiar with the classical name. After such knowledge has been acquired, then ahvays be governed by usage. LAW OF PROJECTILES. In anatomy and physiology, in obstetrics and surgery, in therapeutics and chemistry, we must frequently invoke a reason for the location of a nerve or vessel ; for the direction taken by pus or a bullet ; for a misplaced foetal head in utero ; or for the tracts pursued by pain and motion, when these manifestations are far removed from their logical locality. The above pain, pus, 22 PRACTICAL ANATOMY. foetal, ovoid, bullet, and motion are all projectiles, and act in accordance with this law : A projectile follows 1 . The point of least resistance. 2. The line of greatest traction. 3. The resultant of the two. Grooves Transmitting Vessels and Nerves, and an Application of the Law of Projectiles. You may be surprised, in your subsequent dissection work on the cadaver, to find arteries and nerves, as a rule, in grooves. This, however, is the case, and you are to name the groove according to the name of the artery, except in those cases where the channel so expands as to be of great surgical importance, in which case the space would seem rather to give its name to the vessel. You are to learn and study these grooves according to roof, floor, boundaries, and contents. If you can do this on the cadaver, then you will be competent to do the same thing on a patient. You ask, Why do these structures occupy grooves ? Philosophy answers, projectiles folloiv the line of least resistance. APPLICATION OF THE LAW OF PROJECTILES IN THE CASE OF PAIN REMOTE FROM PLACE OF INJURY. The cranio-spinal nerves are called somatic. Nerves that supply the thoracic, abdominal, and pelvic viscera are called sympatJietic or visceral. A burn on the surface of the body is painful. The pain is violent and quickly reported to the brain. No one, not even the physician, is in doubt as to the location of the pain. The individual nerve-fibres of somatic nerves are of large calibre, and the course of the same is not interrupted by ganglia. These condi- tions would seem to favor rapid, direct transmission of both pain and motion. In cancer of the stomach the pain is in the abdominal walls. In entcralgia the pain is in the region of the umbilicus. In renal colic the pain is in the end of the penis. In ovaritis the pain is in the back, chest, scalp, and upper or lower extremities. In each instance above cited the pain is referred to a territory supplied by cerebro- spinal and not by sympathetic nerves. In each instance the pain originates in a territory supplied by sympathetics. In each instance pain is a projectile, and must obey the universal law of projectiles. It is, then, the duty of physician and student alike to trace out the anatomical tracks by which the pain rationally travels. You will note, further, that in each case above cited the pain was referred or reflected to the skin via those somatic nerves which had their origin nearest the sympathetic plexuses from which the affected organs drew their sympathetic nerve-supply. The only rational conclusion then is, it would seem, this : Pain is referred to somatic areas because these nerves are so constructed as to offer minimal resistance to the transmission of pain. In other words, projectiles follow the line of least resistance. In your dissections you will be expected to find the communications betiveen somatic and sympatJietic nerves. FASCIA (PLURAL); FASCIA (SINGULAR). The word "fascia" will probably occur more frequently in your anatomical reading than any other word. The term means a sack or bundle, but any amount of derivation, any amount of description in books, will give no adequate idea of the application of the word fascia in all its various forms as met in dissect- ing. The structure, to be understood and appreciated, must be seen and studied on the cadaver. I submit this little outline on fascia, hoping thereby to give the student a working basis for intelligent dissection. There are two grand divisions of fasci;u : FUNDAMENTAL PRINCIPLES OF ANATOMY. 23 1. The superficial fascia, found under the skin in every region of the body. This is also called in histology the areolar form of connective tissue. 2. The deep fascia or fascia profunda has the following characters : (1) It is dense, heavy, and strong in some places ; weak in other places. (2) It is attached to bone in subcutaneous areas. (3) It has perforations for cutaneous vessels and nerves. (4) It is attached to all eminences of bone in the vicinity of joints. (5) It is a dense form of connective tissue. (6) It receives many different names in different localities. You will study the following description, and, if necessary, refer to it frequently in your dissections. SPECIAL NAMES AND SPECIAL FUNCTIONS OF FASCIA PROFUNDA. (i) In the upper extremity ; (2) in the lower extremity ; (3) in association with muscles ; (4) in surgical areas ; (5) forming intemnuscular septa. In tlie upper extremity the deep fascia occurs as : 1. Anterior annular ligament lies in front of the carpus. Under this pass the median nerve, flexor sublimis digitorum, flexor profundus digitorum, flexor longus hallucis. This is ^ of an inch thick, extending from the os trapezium on thumb side to the pisiform bone and unciform process of the unciform bone on ulnar side. It is continuous below with the palmar fascia, and above with the deep fascia covering the muscles. Its function is to bind down the structure under it. 2. Posterior annular ligament is behind the carpus. Under it pass the three extensors of the thumb, the three carpal extensors, the extensor indicis, the extensor minimi digiti, the extensor communis digitorum. It is continuous above with the deep fascia covering the muscles, below with the fascia of the back of the hand. It has seven synovial compartments. 3. Palmar fascia has an outer part, the thenar, covering the thenar eminence ; an inner part, covering the hypothenar eminence ; a middle part, covering the great distributing area to the fingers ; a neuro-vasal area, in which are the median nerve, the ulnar nerve, and the superficial palmar arch. It is continuous above with the annular ligament, below with the ligamenta vaginales ; laterally, with the fascia dorsalis. 4. Dorsal fascia is on the dorsum of the hand. It binds the tendons down and holds them together. It is continuous above with the annular ligament ; below, with the extensor tendons. It is called fascia dorsalis mantis, in contra- distinction to the fascia dorsalis pedis. Ligamenta Taginales form dense sheaths for the flexor tendons of the fingers. They are lined with synovial membrane called theca. The thecne terminate in thecal culs-de-sac for all the fingers between the thumb and little finger op- posite the metatarso-phalangeal articulation. The theca; for the little finger and thumb terminate above in the general synovial sac under the anterior annular ligament. Very often the thecae for the little finger and thumb terminate as do the other three digits. SPECIAL NAMES AND SPECIAL FUNCTIONS FOR THE DEEP FASCIA OF THE LOWER EXTREMITY : Fascia lata, the deep fascia on the front of the thigh. It has an iliac and a pubic part, separated by the saphenous opening. It is continuous above with Poupart's ligament ; below, with eminences about the knee. It is very dense and strong. Ilio-tibial band is in reality the aponeurotic insertion of the tensor vaginae femoris muscle. The fascia or band is inserted into the eminences about the outer part of knee. Anterior annular ligament extends from malleolus to malleolus. Under it are found the tibialis anticus, the extensor proprius hallucis, the extensor longus digi- 24 PRACTICAL ANATOMY. torum, the peroneus tertius, the anterior tibial artery and nerve. It is continu- ous above with the deep fascia ; below, with the dorsal fascia. External annular ligament extends from outer malleolus to os calcis. Under it are the peroneus longus and peroneus brevis. On it rest the short saphenous vein and nerve. Internal annular ligament extends from inner malleolus to os calcis. Under it are the tibialis posticus, the flexor longus digitorum, a sheath containing the posterior tibial nerve, artery, and veins ; behind this sheath is the tendon of the flexor longus hallucis. Dorsal fascia fascia dorsalis pedis is on the back of the foot. It covers the extensor muscles and the dorsalis pedis artery. It is continuous above with the annular ligament ; below, with the extensor tendons to the toes. Plantar fascia is on the sole of the foot. It has three parts, an outer or hypothenar, an inner or thenar portion, a central portion. These cover three muscles, forming the first layer. Behind, it is attached to the os calcis ; in front, it is continuous with the ligamenta vaginales. Liganicnta vaginales are strong sheaths for the flexor tendons. They are lined by synovial membrane. These thecae all terminate in thecal culs-de-sac i . 5 inches above the toe-clefts. DEEP FASCIA ASSOCIATED WITH MUSCLES. The location of some muscles is such that their action extraordinarily develops the fascial investment on one surface of the muscle. This is always at the expense of the fascia on the other side of the muscle. The fascia then takes the name of the muscle, as follows : 1 . Masseter muscle, masseteric fascia. 2. Temporal muscle, temporal fascia. 3. Deltoid muscle, deltoid fascia. 4. Supraspinous muscle, supraspinous fascia. 5. Infraspinous muscle, infraspinous fascia. 6. Obturator interims muscle, obturator fascia. 7. Iliac muscle, iliac fascia. 8. Transversalis muscle, transversalis fascia. 9. Pectoralis major muscle, pectoral fascia. 10. Biceps muscle, bicipital fascia. DEEP FASCIA IN SURGICAL AREAS. I. The deep fascia helping to form the base of the axilla is called axillary, suspensory. It is strong, continuous in front with the pectoral ; externally, with the brachial ; posteriorly, with the fascia of the latissimus dorsi. 2. Pelvic fascia has the following names according to muscle, function, etc. : Iliac, iliac muscle ; psoas, psoas muscle ; obturator, obturator internus muscle ; anal fascia, levator ani muscle ; pubo-prostatic, anterior ligament of bladder ; recto-vesical ; pelvic white line ; inner layer of the triangular ligament. 3. Popliteal fascia helps to form the roof of the popliteal space. It possesses some transverse muscular fibres, by which the resiliency of the fascia is kept up in forced extension of the leg. It is perforated by the short saphenous vein and nerve. 4. Cubital fascia covers the cubital fossa in the retiring angle of the elbou . It covers the median nerve, the tendon of the biceps, the brachial artery and its terminals, the radial and ulnar, and some of their branches. It is also called bicipital fascia, semi lunar fascia, and falciform fascia. DEEP FASCIA FORMING INTERMUSCULAR SEPTA. i. The group of muscles on the front of the thigh is separated from the adductor group internally, and from the flexor group posteriorly ; also, the flexor group is separated from the adductor group. 2. The pcrotici muscles are separated from the flexors behind and the group FUNDAMENTAL PRINCIPLES OF ANATOMY. 25 on the anterior surface of the tibia and fibula in front. The superficial group behind is separated from the deep group. 3. The radial group of the forearm is separated from the flexors in front and the extensors behind. The superficial is separated from the deep group on the anterior part of the forearm. 4. Groups of muscles, acting in harmony to discharge some one physiological function, form a musculature. Adjacent musculatures are always separated by septa of deep fascia. Each musculature has its own nerve-supply. Fascial septa are always attached to the bone, being continuous there with the periosteum. APONEUROSIS. The term aponeurosis, in the plural, aponeuroses, applies to dense, strong fascia, in localities where the action of the fascia is intimately asso- ciated in more than a secondary manner with that of a muscle. You will find the aponeurosis of the diaphragm, of the internal and external oblique and trans- versalis muscles of the abdomen, the occipito-frontal aponeurosis, the lumbar, pharyngeal, and vertebral aponeuroses. In these places this structure forms either an integral part of the muscle itself, or constitutes the main structure in the region in which it is found. The terms aponeurosis of investment and inser- tion refer to the structure as forming either a cover for a muscle or its insertion. A single aponeurosis may do both of these. For instance, the aponeurosis of investment for the glutens maximus muscle continues downward, and the muscle is aponeurotically inserted thereby into the deep fascia of the thigh. ORIGIN AND INSERTION OF MUSCLES. These are very arbitrary terms. Usually the more fixed of two points is called the origin, the less fixed point, the insertion. Insertion may be by tendon or by aponeuroses. Notice that many muscles take a large part of their origin from the deep fascia investing them. Attachment applies to both origin and insertion. ANATOMICAL FIBROUS ARCHES. You will, in the course of your reading, see the above expression. The two heads of muscles are always connected by a fibrous arch. The following will illustrate the point : The gastrocnemius, soleus, biceps, flexor sublimis digitorum, pronator radii teres, flexor longus pollicis, the biceps of the thigh. Vessels and nerves are frequently described as passing under the fibrous arch of a muscle. THE SUPERFICIAL FASCIA 1. Is found immediately under the skin ; 2. It has two strata an upper and a lower ; 3. The upper stratum contains fat the panniculus adiposus ; 4. The lower stratum contains the cutaneous vessels and nerves ; 5. It has no fat in the eyelids, penis, and scrotum ; 6. It is not attached to bony eminences ; 7. It has some muscles, called dermals ; 8. Its local special names are cribriform and colles ; 9. Its fat in the palms and soles is called granular fat. THE SEROUS MEMBRANES. You will be able to demonstrate on the cadaver 1 . They are all related to the lymphatic system ; 2. They form air-tight cavities, except the female peritoneum ; 3. They are all thin and transparent ; 4. They completely or partially invest organs ; 5. Peritoneum, pleura, and pericardium are proper serous membranes ; 6. The linings of blood-vessels and joints are subdivisions. 3 26 PRACTICAL ANATOMY, SYNOVIAL MEMBRANES. In your practical work on the cadaver you will find : (i) Articular synovial membrane lining the capsules of movable joints; (2) vaginal synovial membrane lining the ligamenta vaginales, surrounding the tendons to the fingers and toes, and also in other places where a tendon would be exposed to friction ; (3) bursal synovial membrane between an eminence of bone and a muscle playing thereover. The secretion of these synovial membranes is, by virtue of its viscidity, fitted to resist friction. Synovial membranes belong to the class of serous membranes. THE Mucous MEMBRANES. These communicate with the air. You will demonstrate them lining the digestive tract, the genito-urinary passages, and the respiratory tract. The margin between skin and mucous membrane is called a muco-cutaneous margin. You must demonstrate this margin in all regions of the body. The specific name of any muco-cutaneous margin is determined by the name of the region, as : (i) The nasal ; (2) ocular ; (3) oral ; (4) anal ; and (5) vaginal muco-cutaneous margin. These are all anatomical weak points, because they are junctional areas. NERVE-ENDINGS. You should remember that muscles receive both sensory and motor nerves ; that nerve-endings are in tendon, blood-vessel, all the mem- branes, and skin ; that you are not supposed to dissect out these nerve-endings this belongs to histological and physiological research. You are to note where the muscle receives its nerve-supply, usually on the under surface, and then trace the same as far as possible. THE HEAD AND NECK. Any attempt to dissect the general or special regions of the head -and, neck must be preceded by a thorough review of those osteological parts associated (i) with the attachment of muscles ; (2) with the limitation of surgical or physio- logical areas ; (3) with the transmission of vessels and nerves ; (4) with junctional areas, whether the union is fixed, as between the teeth and alveolus, or movable., FIG. 7. THE SKULL. (Norma lateralis. ) as between the mandible and the temporal bone. To accomplish this interesting review let the illustrations in the book, the skull, and the cadaver all be used. (Fig. 7-) I. The complete temporal ridge has (i) a frontal portion ; (2) a parietal portion; (3) a temporal portion. From it arises the temporal muscle and its aponeurosis. The greater p^art of the temporal fossa is limited by it. It begins 27 ; 28 PR A CTICAL ANA TOMY. at the external angular process of the frontal bone and ends in the posterior root of the zygomatic process of the temporal bone. The two ends are connected by the zygomatic arcJi. MENTAL FORAMEN Levator menti Depressor labii inf. THE CHIN OR MENTAL PRO- TUBERANCE Temporal CORONOID PROCESS SIQMOID NOTCH External pterygoid CONDYLE Platysma Depressor anguli oris EXTERNAL OBLIQUE LINE GROOVE FOR FACIAL ARTERY ANGLE FIG. 8. THE MANDIBLE. (Outer view.) External pterygoid Capsule MANDIBULAR SPINE MANDIBULAR FORAMEN Spheno-mandi- bular ligament Superior constrictor Mylo-hyoid groove Internal pterygoid Stylo- mandibular ligament Temporal GROOVE FOR SUB- LINGUAL GLAND Genio-hyo- glOSBUS Qeiiio-hyoid Digastric Mylo-hyoid INTERNAL OBLIQUE LINE GROOVE FOR SUBMAXILLARY GLAND FIG. 9. THE MANDIIU.K. (Inner view.) 2. The zygomatic arch has (i)*a malar and (2) a temporal portion. It is formed by the zygomatic process of the malar and the zygomatic process of the temporal bone. The arch has an upper and a hwr border ; an outer and an inner surface. THE HEAD AND NECK. 29 3. The mandible has a body and a ramus. On the body find : (i) The mental foramen ; (2) the external oblique line ; (3) the alveolar process ; (4) the symphysis menti ; (5) the mental tubercles ; (6) the incisive fossa ; (7) an internal oblique line or mylo-hyoid ridge ; (8) a mandibular spine ; (9) a mandibular foramen ; (10) superior and inferior genial tubercles ; (i i) a digastric fossa ; (12) a submaxillary groove for the submaxillary gland. Zygomaticuo major Zygomaticus minor SURFACE COVERED BY oocipito-frontalis Corrugator superoilii Tendo oculi Crbicularia palpebrarum Levator labii supe- rioris alaeque nasi Levator labii auperioria Levator anguli oris Compressor naris Depressor alee nasi Orbicularis oris FIG. 10. THE SKULL. (Norma facialis.) The ramus has (i) a coronoid process ; (2) a sigmoid notch ; (3) a condylar process. The condylar process consists of a condyle and a neck. ON THE FACE LOCATE (Fig. 10) : (i) The anterior nares ; (2) the nasal bones ; (3) the temporal, frontal, orbital, and maxillary processes of the malar bone ; (4) the supraorbital and infraorbital arches ; (5) the internal and external angular processes of the frontal bone ; (6) the floor of the orbit, and in it the infraorbital canal, containing an artery, nerve, and vein of the same name ; (7) the infra- orbital foramen, the terminus of the infraorbital canal ; (8) the supraorbital 3 PRACTICAL ANATOMY. Maseeter Tensor palati Azygos uvulae Superior constrictor Internal pterygoid Tensor palati Tensor tympanl Levator palati Rectus capitis anticus major Rectus capitis anticus minor Anterior common ligament of spine Vertical part of crucial ligament Check ligament Capsular ligament Posterior oeeipito-atlantal ligament Superior oblique Rectus capitis posticus major Rectus capitis postious minor Iiigamentum nuchse _ Trapezius 1 i<;. ii. -Tin SK.UI.L. (Nonna hasilaris.) THE HEAD AND NECK. 31 foramen in the frontal bone ; (9) the intermaxillary suture ; (10) the naso-frontal suture ; (i i) the superciliary ridge ; (12) the interfrontal or metopic suture or its remains. ON THE BASE OF THE SKULL (Fig. 1 1) LOCATE: (i) The foramen magnum ; (2) the occipital condyles ; (3) the digastric groove for the posterior belly of the digas- tric muscle ; (4) the jugular process for the rectus capitis lateralis ; (5) the styloid process of the temporal bone ; (6) the glenoid fossa with the Glaserian fissure dividing the articular from the non-articular part of the same ; (7) the internal and external pterygoid plates of the pterygoid process of the sphenoid bone ; (8) the pterygoid fossa for the internal pterygoid muscle ; (9) the jugular foramen for the ninth, tenth, eleventh nerves and jugular vein ; (10) the carotid canal in the petrosa for the internal carotid artery and sympathetic nerve ; (i i) the foramen spinosum for the great meningeal artery ; (12) the posterior nares 1(13) the hard palate ; (14) the hamular process, around which plays the circumflexus palati. LOCATE THE ATTACHMENT OF THESE MUSCLES (Figs. 7-10): (i) Temporal ; (2) masseter ; (3) pterygoid, internal and external ; (4) buccinator ; (5) platysma ; (6) digastric ; (7) orbicularis oris ; (8) depressor labii inferioris ; (9) levator menti ; (10) levator labii superioris ; (i i) levator anguli oris ; (12) corrugator supercilii ; (13) zygomaticus, major and minor ; (14) compressor naris ; (15) depressor alae nasi ; (i 6) levator labii superioris alaeque nasi ; (17) the rectus capitis anticus, major and minor; (18) the tensor palati; (19) the azygos uvulae; (20) levator palati ; (21) tensor tympani ; (22) depressor anguli oris. LOCATE THE FOLLOWING FISSURES : (i) The fronto-parietal ; (2) the temporo- parietal ; (3) the interparietal or sagittal ; (4) the occipito-parietal ; (5) the interfrontal ; (6) the fronto-nasal ; (7) the fronto-maxillary ; (8) the malo-frontal ; (9) the malo-zygomatic ; (10) the malo-maxillary ; (11) the naso-maxillary ; (12) the intermaxillary ; (13) the symphysis menti ; (14) the spheno-maxillary ; (15) the petro-occipital ; (16) the palato-maxillary ; (17) temporo-mandibular and occipito-atloid articulations are the only movable joints in this region. INCISIONS FOR LOCATING THE FOLLOWING STRUCTURES : 1. The supraorbital nerve, artery, and vein (fifth nerve and seventh nerve). 2. The infraorbital nerve, artery, and vein (fifth nerve and seventh nerve). 3. The mental nerve, artery, and vein (fifth nerve and seventh nerve). 4. The facial artery and vein and their branches. 5. The facial nerve and its facial branches and communications. 6. The duct of Stenson and transverse facial artery. The Mental Nerve. Turn the skin aside from the intersectional point indi- cated in figure 1 2. With the forceps dissect out the leash of mental nerves, anp find them continuous with branches of the facial nerve, or seventh cranial. (Fig. 1 6.) Find also the mental branch of the inferior dental artery coming through the same foramen the mental. The Supraorbital Nerve. Turn the skin back, beginning at the intersectional point in the figure. Find with the forceps the leash of the supraorbital nerve (Fig. 1 6) anastomosing with the supraorbital part of the facial portion of the seventh nerve. The Infraorbital Nerve. Turn the skin back, beginning at the intersectional point in the figure. Here, with the forceps, you will find a large leash of nerves, the terminus of the infraorbital nerve. You will see that its branches are con- tinuous with the infraorbital portion of the seventh cranial nerve. Find also the branches of the infraorbital artery accompanying the nerve. Stenson' S duct is the excretory duct for the parotid gland. Turn the skin back from the intersectional point indicated. Above the duct you will find the transverse facial artery, a small branch of the temporal. Below the duct you will find branches of the facial nerve. 32 PRACTICAL ANATOMY. The levator labii superioris covers the infraorbital nerve and artery. This muscle arises from the margin of bone below the orbit. (Fig. 10.) It is inserted into the orbicularis oris. The levator anguli oris arises from the canine fossa below the infraorbital foramen. It is inserted into the angle of the mouth. It may be seen by pulling the leash of nerves to one side. The leash of nerves lies between the above two muscles. (Fig. 10.) The Depressor Labii Inferioris. Remove the skin a little further in the region of the mental nerves, and find the depressor of the lower lip. This muscle is quadrangular in form. Fully one-half of its outer surface lies under \ \ FIG. 12. PRIMARY INCISIONS IN DISSKCTION 01 THE KACK. the depressor anguli oris (Fig. 13). The muscle arises from the upper part of the external oblique line of the mandible, and is inserted into the lower lip. The depressor anguli oris (Fig. 13) will be found arising from the lower part of the external oblique line of the mandible. It is triangular in form. It over- laps the outer one-half of the depressor labii inferioris. Now cut the origin of this muscle, and pull the same aside and expose the whole of the muscle that it overlaps. (Fig. 17.) CAUTION. In all dissections about the face care must be taken to cut close to the skin. The branches of the seventh nerve lie beneath the muscles and can not be injured if you take the precaution just given. THE HEAD AND NECK. 33 The Orbicularis Oris. Remove the skin around the mouth and expose this muscle. (Fig. 14.) This muscle has a rather strong'fascial attachment to the alveolus of the superior maxilla. ^ The zygomatici major and minor (Fig. 14) arise from the malar bone, and are inserted into the outer part of the upper lip. The levator labii superioris alaeque nasi is inserted into the wing of the nose and the upper lip. It arises from the nasal process of the superior maxilla, on the margin of the orbit. Corrugatpr supercilii Pyramidalis Levator labii superioris alaeque naai Levator labii superioris Compressor narium Levator anguli oris Naso-labialis Depressor alae nasi Orbicularis oris Buccinator Depressor anguli oris Depressor labii inferioris Levator inenti Mylo-hyoid Anterior belly of digastric Temporal Zygomaticua major Posterior belly of digastric Splenius capitis Stylo-hyoid Sterno-maatoid Levator anguli scapulae Scalenus medius Scalenus anticus FIG 13 THE DEEPER LAYER OK THE MUSCLES OF THE FACE AND NECK. The Orbicularis palpebrarum surrounds the base of the orbit. It consists of two sets of fibres. One, called the palpebral, covers the palpebra> or lids ; the other is external to this, and blends above with the occipto-frontalis muscle. It has, internally, a firm, triple attachment to the internal angular process of the frontal bone, and to the nasal process of the superior maxilla. Between these two you will find a short, stout tendon that can be mistaken for nothing else the tendo oculi or tendo palpebrarum. Figure 10 shows its origin from the nasal process of the superior maxilla in front of the lachrymal groove. Trace the tendon toward the upper and lower lids and observe how it divides. 34 PRACTICAL ANATOMY. The Levator Menti, or Levator Labii Inferioris (Fig. 13). This is the muscle by which the low"er lip is protruded and elevated at the same time. Cut th/ough the mucous membrane and you will come to the muscular fibres. This muscle arises from the incisive fossa, and is inserted into the integument of the chin, on a plane lower than the origin of the muscle. The compressor narium (Fig. 14), a small muscle, arises from the superior maxilla. (Fig. 10.) It is inserted, by an aponeurosis across the bridge of the nose, into its fellow of the opposite side. This is a small muscle at best, and very hard to demonstrate on prepared material. Epicranial aponeuroais Orbicularis palpebrarun Fyramidalis Levator labii superior-is alscque na3i Compressor narium Dilatator naris anterior Dilatator uaris posterior Levator labii superioris Zygomaticus minor Levator anguli or is Orbicularis oris Depressor labii inferioris Depressor anguli oris FIG. 14. THE SUPERFICIAL MUSCLES OK THE HEAD AND NECK. The corrugator supercilii (Fig. 13) is seen by cutting in the mid-line above the nose through the skin and fasciae. It arises from the superciliary ridge (Fig. 10), and is inserted into the under part of the orbicularis palpebrarum. In action it produces the deep vertical furrows of the forehead. The pyramidalis nasi (Fig. 14) is a part of the occipito-frontalis, continued on to the nose, and inserted into the compressor narium. The dilator naris anterior arises from the lateral cartilage of the nose, and is inserted into the skin near the margin of the nose, well in front. THE HEAD AND NECK. 35 The dilator naris posterior arises from the superior maxillary bone, from the nasal notch, and is inserted into the skin of the margin of the nostril, well back. These two dilator muscles antagonize the compressor nariinu. Remove the skin from the forehead, and expose the anterior belly of the occipito-frontalis. We are at present concerned only with the insertion of this muscle. Its anterior fibres are continued on to the nose as the pyramidalis nasi ; its middle and outer blend with the outer portion of the orbicularis palpebrarum. The muscles of facial expression, those which you have just dissected, are called dermal muscles, on account of their insertion, being of such a nature as to move the skin, in a most unique manner. These muscles are innervated by the facial or seventh cranial nerve. (Fig. 16.) They are in the superficial fascia in fact, they occupy the fascia to such a degree that some good authors speak of the absence of facial superficial fascia. By their action they confer on the human face facial expression in its broadest sense. Is not the facial nerve more than an ordinary motor nerve ? In other words, FIG. 15. SCHEME OF FACIAL NERVE COMMUNICATING WITH THE FIFTH CRANIAL NERVE. is not this nerve eligible to promotion from the rank and file of ordinary motor nerves to a place among those nerves which are designated special sense nerves ? For the sake of arousing your interest in the difficult dissection of this nerve, you will pardon a digression for the purpose of answering the above questions. A slight blow on the ligamentum patellae produces reflex extension of the leg on the thigh. The steps were (i) conduction of pain, by a sensory nerve, to a cortical motor area, and (2) an almost simultaneous contraction of the extensor quadriceps femoris ; (3) a record of the blow was recorded as memory. A com- plete moto-sensory cycle was the result. The nerve that conveyed the sensation of pain to the brain is called a nerve of common sensation ; the one that produced motion in the extensor muscles is called a motor nerve. The retina responds to light, the auditory nerve to sound, the olfactory, to odors. Each nerve records its experience in the brain. Now, see what the facial nerve does ! It produces motion of a reflex character, as do ordinary motor nerves. It is the only nerve by which vision, audition, olfaction, and 36 PRACTICAL ANATOMY. gustation manifest themselves in the primitive state. The sight of cruelty, the sound of martial music, the odor of Limburger cheese, the taste of some extra- ordinary viand, are facially expressed, and read off by the world as disapproval, patriotic enthusiasm, repulsion, satisfaction. If, then, auditory, optic, and gustatory nerves are capable of conveying an impression to the brain for record, are they entitled to the designation " special sense " any more than is the facial, which does its own work, and facially expresses to the world the recorded experiences of all the so-called nerves of special sense ? Is not this nerve a special sense nerve of facial pantomime ? SUPRA-ORBITAL PALPEBRAL TWIG OF" LACHRYMAL INFRA TROCHLEAR TEMPORAL BRANCH OF SEVENTH MALAR BR. OF SEVENTH MAXILLARY 1)1 V. OF FIFTH INFRA- ORBITAL BR. OF SEVENTH BUCCAL BRANCH OF SEVENTH MENTAL BRANCH OF MANDIBULAR S UPRA -MA NDIB ULA R BRASCH OF SEVENTH INFRA -MA NDIB t Y, .1 K BRANCH Of SEVENTH POSTERIOR AURIC I "I. Ml A URICULO- TEUPORAL GREAT OCCIPITAL FACIAL LESSER OCCIPITAL GREAT A URICULAR SUPERFICIAL CERVICAL FIG. 16. SUPERFICIAL DISTRIBUTION OF THE FACIAL AND OTHKK NKRVKS OF TIIK HKAD. (After Hirschfeld and Leveille.) The Facial Nerve (Fig. 16): Its Dissection on the Face. Remove the skin. Cut down through the parotid gland in the direction of the vertical line in figure 1 2. It is necessary to go through about one-half of an inch of gland sub- stance. Take the forceps, and find a nerve trunk about the size of a knitting- needle. This will be the inferior division of the nerve the cennco-facial part. Follow this branch up a little further, and, very deeply located, you will find the main tnin/c of the nerve. From this you can trace out all the facial branches, in this manner : Put a small piece of tape around the main trunk. Pull on this, THE HEAD AND NECK. 37 and at the same time cut the skin, fascia, and gland substance, in the direction of the branches, with scissors. You will find dissection of this nerve somewhat difficult the first time you make the trial. Any amount of advice, added to what has previously been said, will not help you. Just be careful, and expose one branch at a time. Communications of the Facial Nerve on the Face with other Nerves (Fig. 15): 1. The seventh nerve -f- mental branch of the fifth nerve at mental foramen. 2. The seventh nerve + infraorbital branch of the v fifth nerve at infraorbital foramen. 3. The seventh nerve + supraorbital branch of the fifth nerve at supraorbital foramen. 4. The seventh nerve -f- auriculo-temporal branch of fifth on temporal muscle. 5. The seventh nerve + malar branch of temporo-malar of fifth nerve on malar bone. 6. The seventh nerve + temporal branch of temporo-malar of fifth nerve above zygoma. 7. The seventh nerve -f- great auricular nerve of cervical plexus behind the ear. 8. The seventh nerve -j- small occipital nerve of cervical plexus behind the ear. 9. The seventh nerve -f- lachrymal and infratrochlear branches of the fifth nerve. 10. The seventh nerve -J- great occipital. Posterior division of second cer- vical nerve. It will appear from the foregoing that the nerve-supply of the face is a very complicated proposition. Such, however, is not the case, since the whole nerve- distribution can be reduced to : 1. Motor nerves to the muscles of expression = seventh nerve. 2. Sensory nerves to the skin over the muscles = fifth nerve. 3. Sympathetic nerves the nervi molles on facial artery. 4. Communicating branches to adjacent areas. Divisions and Facial Branches of the Facial Nerve. The nerve divides into two branches : (i) An upper division that supplies the upper half of the face and the temporal region ; (2) a lower division that supplies the lower half of the face and the neck. (Fig. 16.) The temporo-facial division gives off : 1. Temporal branches to the temple and forehead. 2. Infraorbital branches below the orbit. 3. Malar branches to the zygomatic muscles. The cervico-facial division gives off : 1. A buccal branch to the buccinator muscle. 2. A supramandibular branch above the jaw. 3. An inframandibular branch below the jaw. The name pes anscrinus is applied to the divergence of these six nerves from the two primary divisions of the seventh nerve. The auriculo-temporal nerve will be found in front of the ear just behind the temporal artery. It is a sensory branch of the fifth, and supplies the side of the scalp and the external in front with sensation. Find these arteries on the face (Fig. 1 7) : 1. The frontal in the inner angle of the orbit. 2. The nasal above the tendo oculi. 3. The lachrymal in the outer angle to the upper lid. 4. The transverse facial on the malar bone. 3 8 PRACTICAL ANATOMY. 5. The supraorbital, with the supraorbital nerve. 6. The infraorbital, with the infraorbital nerve. 7. The mental, with the mental nerve. 8. The facial artery (Fig. 17) crosses the mandible in front oi the masseter muscle. It is surrounded by some very delicate sympathetic nerves, Orbicularia palpebrarum muscle Transverse facial artery Zygomatious minor muscle Zygomatious major muscle Buccinator muscle Masseterie branch Masseter muscle Stylo-pharyngeus muscle Stylo-glossus muscle Ascending palatine branch Tonsillar branch Facial artery External carotid artery Posterior belly of digastric muscle Lingual artery Frontal branch of ophthalmic artery Nasal branch of ophthalmic artery Angular artery Levator labii super- ior is et alas nasi muscle Infraorbital artery Le'vator labii super- ioris proprius Lateralis nasi ar. Levator anguli oris muscle Artery of septum Superior coronary artery Risorius muscle Inferior coronary artery Mental branch of inferior dental artery Depressor labii inferioris muscle Inferior labial arlrrti Depressor anguli oris muscle Submental artery Branches to sitbmaxillary gland Anterior belly of digastric muscle Mylo-hyoid muscle Hyo-glossus muscle HYl'OtiLOSSAL NERVE Kic. 17. SCIIKMK OK TIIK FACIAL ARTKRY. which can be demonstrated, if you remove all the fat, with ether, and permit the ether to evaporate. These nerves are the ncri'i uiolles. They regulate blushing. H miidics of the /'*iifid/ Artery on the Face : 1. The inferior coronary, between mucous membrane and orbicularis oris. 2. The superior coronary, between mucous membrane and orbicularis oris. 3. The inferior labial, under the muscles of the chin. THE HEAD AND NECK. 39 4. The lateralis nasi, to the side of the nose. 5. The angular, to the inner angle of the orbit. 6. Muscular branches to the various muscles. Anastomosis takes place between the facial and all the arteries on the face above enumerated. The veins of the face (Fig. 18) accompany the arteries, and take the same names, as a rule. (Fig. 17.) They must be dissected with the arteries and Frontal Stipraorbital vein Communication with ophthalmic vein Transverse nasal vei> Angular vein Lateral nasal veins Transverse facia vein Superior labial or coronary vein Anterior pterygoid or deep facial vein Inferior coronary vein Facial vein Inferior labial vein Submental vein Lingual vein Superior thyroid vein Middle thyroid vein Sterno-mastoid Anterior jugular vein Communication between anterior jugular veins Platysma Anterior temporal vein Posterior temporal rein Deep temporal vein Parotid lymphatic glands Common temporal vein Internal maxillary vein Occipital vein Temporo-maiillary vein Posterior auricular vein Occipital lymphatic glands Sterno-masloid lymphatic glands Communication between facial and external jugular veins Svbmaxillary lymphatic glands Internal jugular vein Posterior external jugular vein External jugular vein Superficial cervical chain of glands - Transverse cervical vein ^- Suprascapular vein Jugido-cephalic vein m FIG. 18. THE SUPERFICIAL VEINS AND LYMPHATICS OF THE SCALP, FACE, AND NECK. nerves. These veins must be handled very carefully, not to be injured, as they are very easily ruptured. Observe the deep temporal vein piercing the temporal fascia, above the zygoma. This returns blood from the temporal muscle. Observe the confluence of the internal maxillary vein, in front of the ear, in the substance of the parotid gland, with the temporal vein, and the result of their confluence the temporo- inaxillary vein. Observe the communication between the facial vein and the external jugular; also the communication between the angular, supraorbital, and ophthalmic veins. Erysipelas of the face may reach the meninges through this communication. The ophthalmic vein opens into the cavernous sinus. 40 PRACTICAL ANATOMY. The parotid gland (Fig. 20) is located by limitation : 1. Superiorly, limited by the zygomatic arch. 2. Inferiorly, limited by the angle of the mandible. 3. Anteriorly, limited by the mid-line of the masseter. 4. Posteriorly, limited by the mastoid process and sterno-mastoid. 5. It sends in prolongations as follows (Fig. 19) : The inner surface is irregular, sending (i) a large process of gland tissue, in front of the styloid process of the temporal bone, the same also occupying the non-articular part of the glenoid cavity ; (2) a large process behind the styloid and under the mastoid process and sterno-cleido-mastoid muscle. Parotid fascia is the name given to the deep fascia covering the outer sur- PALATINE PROCESS OF SUPERIOR MAXILLA ZYGOMATIC ARCH HORIZONTAL PLATE OF PALATE BONE GLENOID FOSSA rrnlid Gland STVLOID PROCESS Parotid Gland MASTOID PROCESS FIG. 19. SHOWING SCHEMATICALLY THE DEEP PART OK THE PAROTID GLAND EMBRACING THE STYLOID PROCKSS. face of this gland. You have already cut through the gland vertically to find the seventh nerve. Contents of the Parotid Gland : 1. The facial nerve and pes anserinus. 2. The auricula-temporal branch of the fifth nerve. 3. The external carotid artery and its three terminals. 4. The posterior auricular, temporal, and transverse facial arteries. 5. The internal maxillary artery and vein. 6. The temporo-inaxillary vein. 7. A branch of the great auricular nerve to the seventh. Excretory Duct of the Parotid (Fig. 20). Stenson's duct crosses the masseter muscle on a line from the centre of the upper lip to the lobule of the ear. It perforates the buccinator muscle, and opens into the vestibule of the oral cavity, opposite the second upper molar tooth. THE HEAD AND NECK. 41 1 . Hozv may the dermal muscles be grouped ? They may be grouped about the four apertures : the orbit, the ear, the nose, and the mouth. Their action seems to be secondary to the special senses of hearing, smell, sight, and taste, since they open and close these openings to a variable extent. 2 . Give the bony attachments of the orbiculans oris. This muscle is attached to the upper and also to the lower incisive fossa, and to the alveolar processes. 3. Has the orbiculans oris any antagonists? If so, name them. Yes ; superiorly, levator labii superioris, levator anguli oris, zygomaticus minor, zygomaticus major ; inferiorly, depressor labii inferioris, depressor anguli oris, levator menti, risorius. SOCIA PAROTIDIS SUBLINGUAL GLAND DUCT OF SUBMAXILLARY GLAND Mylo-hyoid muscle Anterior belly of digastric muscle DEEP PORTION OF SUBMAXILLARY GLAND FIG. 20. THE SALIVARY GLANDS. PAROTID GLAND Massetcr muscle Ster no -m astoid muscle Posterior belly of digastric muscle SUBMAXILLARY GLAND. DRAWN BACKWARDS Loop of fascia 4. Name the foramen between the origins of the levator labii superioris and the levator anguli oris. The infraorbital, transmitting the infraorbital vessels and nerves. 5. Locate on a patient the foramen mental c t and tell what it transmits. This foramen is located at the junction of the mento-Meckelian and dentary parts of the mandible, one-half of an inch below the gingiva of the second bicuspid tooth ; it transmits the mental branches of the inferior dental vessels and nerves. 6. What is the function of the mental nerves and with what do they communi- cate ? The function is to supply the skin of the lower lip and chin ; they communi- cate with mental branches of the facial nerve. 7. Name the aural group of dermal muscles, and give their function. Attrahens aurem, attolens aurem, retrahens aurem. These muscles are mere vestiges in man, often incapable of demonstration. They are best studied on domestic animals, as the dog and rabbit. Their function is, first, to enlarge the 4 42 PRACTICAL ANATOMY. auditory canal by rendering tense the cartilaginous parts ; and, second, to direct the external ear toward a given noise. These muscles are supplied by the seventh cranial nerve. 8. Describe the rationale of a complete frown. A proper frown consists of vertical and horizontal corrugations. The verti- cals are produced by the action of the corrugator supercilii on the anterior belly of the occipito-frontalis muscle, acting on this so as to deflect inward its muscular belly and the skin covering the same. The horizontal ridges are the result of the same force, intensified to some extent by gravity. 9. Locate the infraorbital plexus and give its formation. It is located one-half of an inch external to the wing of the nose. It lies Submaxillary Superior carotid Occipital Inferior carotid Fir,. 21. CERVICAL TRIANGI.KS. under cover of the levator labii superioris, and is formed by a. communication between the infraorbital branch of the fifth and the infraorbital branches of the seventh nerve. 10. Name and locate the great anastomotic blood areas on the face and tell limv they are formed, The facial branch of the external carotid, the ophthalmic branch of the internal carotid artery, the internal maxillary branch of the external carotid, and the temporal branches of the external carotid are the branches of arterial trunks concerned in the rich blood-supply to the face. Anastomotic areas: (Fig. 17) (i) The ophthalmic anastomoses with the tem- poral, forming the supraorbital anastomosis, and with the angular branch of the facial artery at the iniu-r base of the orbit, forming the angular anastomosis. ( 2) The transverse facial artery anastomoses with the masseteric branch of the THE HEAD AND NECK. 43 facial artery on the outer surface of the masseter muscle, forming the masseteric anastomosis. (3) The infraorbital anastomoses with the facial, below the orbit, to form the infraorbital anastomosis. (4) The mental branch of the inferior dental artery anastomoses with the inferior labial branch of the facial artery, forming the mental anastomosis. (5) In the facial mid-line the corresponding arteries of opposite sides of the face anastomose. At the aural, ocular, nasal, and oral muco-cutaneous junctions capillary anastomosis takes place. (6) The arterial anastomoses above referred to are attended by venous anastomoses. The mental, infraorbital, and supraorbital may be compressed at their respective exit foramina. The facial may be compressed on the mandible just in front of the masseter muscle. (7) The important communication on the face is between the ophthalmic and angular, by which route facial erysipelas may reach the meninges, since the ophthalmic vein opens into the cavernous sinus of the dura mater. 1 1 . Explain briefly the parotid gland. The gland is located in a depression having the following limitations : above, the zygomatic arch ; below, the angle of the mandible and the masto-mandibular line; behind, the external ear and sterno-mastoid muscle; in front, by the masseter muscle ; deeply, it embraces the styloid processes and internal carotid artery. The gland contains the seventh nerve and the auriculo-temporal branch of the fifth nerve, both of which furnish it with nerve -filaments. It contains the external carotid artery, which here breaks up into the temporal, internal maxillary, and transverse facial branches ; these supply the gland with blood. It contains the temporo-maxillary vein. The fascial covering of the gland is called the parotid fascia. The gland is the largest of the salivary glands, and has an excretory duct called Stenson's. 12. Trace Stenson's duct. It crosses the masseter muscle in a line from the lobule of the ear to the upper lip. It perforates the buccinator muscle, and opens into the vestibule of the cavum oris opposite the second upper molar tooth. 13. Where does the facial nerve escape from the cranium ? It escapes through the stylo-mastoid foramen, in the petrosa of the temporal bone. On its escape it gives off the posterior auricular, the digastric, and stylo- hyoid branches. It subsequently forms the pes anserinus, from which the muscles of expression are innervated. The facial is a motor nerve. NOTE. Many a good dentist has been heard to tell his patient, "All this toothache is caused by the facial nerve." The facial nerve makes you smile when you hear such things ; it is the fifth nerve that is concerned in toothache. THE NECK. SUPERFICIAL DISSECTION. Locate on the cadaver : 1. The lower border of the mandible and its angle. 2. The mastoid process of the temporal bone, behind the ear. 3. The sterno-clavicular articulation. Does it move? 4. The interclavicular or suprasternal notch. How deep? 5. The acromio-clavicular articulation. Does it move? 6. An imaginary line from the angle of the jaw to the mastoid. 7. The sterno-cleido-mastoid muscle and its double origin. 8. The exact anterior border of sterno-cleido-mastoid. 9. The exact posterior border of sterno-cleido-mastoid. 10. The cervical mid-line mento-sternal line. 44 PRACTICAL ANATOMY. 1 1. The hyoid bone in the mid mento-sternal line. 1 2. The body of the hyoid bone, one-half of an inch long to touch. 13. The greater horn of the hyoid -{- lingual artery above same. 14. The thyroid cartilage Adam's apple and notch above, i 5 . The thyro-hyoid space + thyro-hyoid membrane. 1 6. The thyroid notch -f- mid-part of thyro-hyoid membrane. 17. The crico-thyroid membrane in crico-thyroid space. 18. The cricoid cartilage and trachea. (Fig. 27.) INCISIONS. 1 . Through the mid mento-sternal line. 2. From symphysis menti to mastoid process. 3. From sternum to acromion process. BOUNDARIES OF THE NECK. 1 . Anterior. -The mid mento-sternal line. 2. Posterior. The anterior border of the trapezius. 3. Inferior. The clavicle and manubrium sterni. 4. Superior. Lower border of mandible and masto-mandibular line. TRIANGLES OF THE NECK. (Fig. 21.) 1 . Submaxillary or digastric. 2. Superior carotid or triangle of election. 3. Inferior carotid, tracheal, or triangle of necessity. 4. Occipital not suboccipital. 5. Subclavian or brachial triangle. BOUNDARY STRUCTURES OF CERVICAL TRIANGLES. (Fig. 23.) 1 . The sterno-cleido-mastoid muscle. 2. The mid mento-sternal line. 3. The lower border of the mandible. 4. The masto-mandibular line. 5. The omo-hyoid muscle. 6. The digastric muscle. 7. The stylo-hyoid muscle. 8. The manubrium sterni and clavicle. SURGICAL AND MEDICAL AREAS OF THE NECK. Larynx intubation and laryngotomy. Trachea tracheotomy, high and low. Thyroid gland operations on. The contents of the carotid sheath. The subclavian artery and its branches. The brachial and cervical plexuses. The apex of the lung, one and one-half inches above the first rib. Traclical and bronchial respiration. The superficial lymphatic glands. (Fig. 23.) The upper set of deep lymphatic glands. The low i- sc/ of deep 'lymphatic glands. THE HEAD AND NECK. 45 SPECIFIC BOUNDARIES OF CERVICAL TRIANGLES. (Fig. 23.) 1. Digastric Triangle. Mandible and masto-mandibular line ; anterior belly of digastric muscle ; posterior belly of digastric muscle and stylo-hyoid muscle. 2. Superior Carotid Triangle. Sterno-cleido-mastoid muscle ; anterior belly of omo-hyoid muscle ; stylo-hyoid muscle and posterior belly of digastric muscle. 3. Inferior Carotid or Traclieal Triangle. Mid mento-sternal line ; sterno- cleido-mastoid muscle ; anterior belly of omo-hyoid muscle. 4. The Occipital Triangle. The trapezius muscle; the posterior belly of the omo-hyoid muscle ; the sterno-mastoid muscle. 5. 'The Subclaman Triangle. The clavicle ; the posterior belly of the omo- hyoid muscle ; the sterno-cleido-mastoid muscle. Note that the sterno-mastoid divides the neck into two triangles. Of these two the anterior contains three, the posterior two, smaller triangles. Dissection to sJwiv superficial structures in the superficial fascia of tJie neck, as follou'S : 1 . The platysma myoides muscle a dermal. 2. The anterior jugular vein is in front of sterno-mastoid. 3. The posterior jugular vein is behind the sterno-mastoid. 4. External jugular vein crosses the sterno-mastoid. 5. The superficial lymphatics vertical group. (Fig. 23.) 6. The superficial lymphatics transverse group. (Fig. 23.) 7. The inframandibular branch of the seventh nerve. (Fig. 22.) 8. The superficial cervical nerve, of cervical plexus. (Fig. 22.) 9. The great auricular nerve, of cervical plexus. (Fig. 22.) 10. The small occipital nerve, of cervical plexus. (Fig. 22.) 11. The suprasternal nerve, of cervical plexus. (Fig. 22.) 12. The supraclavicular nerve, of cervical plexus. (Fig. 22.) 13. The supraacromial nerve, of the cervical plexus. (Fig. 22.) The platysma myoides (Fig. 14) is a dermal muscle. It is allied to the muscles of expression and to the three dermal aural muscles ; they are all rem- nants in man of the great panniculus carnosus. To expose this muscle it will be necessary to exercise the greatest care in removing the skin. Usually the fibres of origin of this muscle extend two .inches below the clavicle. They are continued obliquely upward and forward onto the face. In some persons this muscle is very heavy ; in others it is almost absent. The Superficial Nerves of the Cervical Plexus and the Spinal Accessory Nerve. Dissection. Locate the posterior border of the sterno-cleido-mastoid muscle. Very carefully cut the platysma along this posterior border, using the forceps for a director. Next cut through the deep fascia along the posterior border of the muscle. Now look first for a small nerve that parallels the posterior border of the sterno-cleido-mastoid muscle. (Fig. '22. ) This is the lesser occipital. Trace it upward, as in the figure. Three nerves cross the sterno-cleido-mastoid: (i) The mastoid branch, or second small occipital ; (2) the great occipital ; (3) the superficial cervical. Follow their branches out, taking care to harm no veins. These are the three ascending branches of the plexus. The spinal accessory nerve is sometimes the subject of surgical procedure. On the living, if you are in doubt as to whether you have the spinal accessory or some other nerve, remember this rule : Pinch the nerve with the forceps, and if it is the spinal accessory you have, the trapezius muscle will elevate the shoulder-blade. The other nerves that this one is sometimes mistaken for are all sensory, and will, if pinched, produce no muscular contraction. 46 PRACTICAL ANATOMY. The descending branches of the cervical plexus are (i) the suprasternal, (2) the supraclavicular, (3) the supraacromial. Trace these out, as in figure 22. Note that the superficial cervical branch passes behind the external jugular vein ; that it is distributed to almost the entire front of the neck ; that it anasto- moses above with the inframandibular branch of the seventh nerve and below with the suprasternal. Note the spinal accessory nerve pierces the tapezius muscle, and has many communications with the other nerves in the occipital triangle. To this fact is POSTERIOR A URICULAR NERVE FACIAL NERVE AURICULAR BR. OF ORE A T A URICULAR INFRAHANVIBULAR SUPERFICIAL CERVICAL BRANCHES OF SUPER- FICIAL CERVICAL NER VE SUPRASTERNAL ) BRANCHES OF }- GREA T \ AURICULAR C RE AT OCCIPITAL LESSER OCCIPITAL GREAT AURICULAR MASTOID BR. OH 2nd SMALL OCCIPITAL SPI.VAL ACCESSORY TWIGS FROM THE .VASTOID BRANCU BR. TO LKVATOR A\<;ri.i si-AWLji SI' PR A- A CROMIAL Sl'PRACLAVICCLAR BRANCHES TO TR APEX I US si 8OPBACU.rtC1tLAM FIG. 22. SUPERFICIAL BRANCHES OF THE CERVICAL PLEXUS. (After Hirschfeld and Leveille.) possibly due the twitching of the shoulder in frostbitten ears ; purely a reflex movement. (Fig. 22.) The Superficial Lymphatic T. This will enable you to remember the general distribution of the superficial lymphatic glands in the neck. (Fig. 23.) In the main the lymphatics follow the veins. They are readily seen win 11 enlarged by disease ; they are scarcely recognizable in cadavers when not diseased. The jugular veins (Fig. 18) in the superficial fascia are : (i) The anterior, near the mid inento-sternal line. It opens into the *iibela:>ian rein or into the external jugular under the stcrno-cleido-mastoid muscle. (2) The posterior jugular THE HEAD AND NECK. 47 vein parallels the posterior border of the sterno-cleido-mastoid muscle. It opens into the external jugular vein. (3) The external jugular 'vein crosses the sterno- cleido-mastoid muscle. It is formed, as you must show, by the confluence of (i) the temporo-maxillary, (2) the posterior auricular and facial communicating branch. THE DEEP CERVICAL FASCIA. I desire the student to have a conception of the deep fascia of the neck, in advance of his work. The following scheme will greatly assist him both in review and during the dissection. i . The deep fascia ensheathes the contents of the neck in four strata. The Horizontal ramus of lymphatic T Vertical ramus of lymphatic T , FIG. 23. SUPERFICIAL LYMPHATICS. student is expected to learn just what structures are ensheathed by each layer of fascia. 2. The deep fascia has superior attachments, relations, and specializations ; it also has inferior attachments and continuations, thoracic and maxillary, which the student must learn if he ever expects to dissect the neck and thorax under- standingly. 3. The deep fascia forms septa and sheaths, the rationale of which must be read and studied in the introductory chapter of this book. The deep fascia here, as in every region of the body, belongs to the dense compact variety of connective tissue. 48 PRACTICAL ANATOMY. 4. The deep fascia determines the course taken by pus and missiles, hence a thorough knowledge of the architecture of the deep fascial envelopes of the neck is just as important as any fascial area in the body. Figure 24 represents schematically a transverse section of the neck. From this it will be seen there are two spaces: (i) Those formed by delamina- tion of the four layers, including certain structures and their nerve-supply and blood-supply. (2) The interfascial spaces containing fat and connective tissue. It will be seen that the first layer delaminates to unsheath the sterno-rnastoid muscle. The second layer delaminates to enclose the omo-hyoid, sterno-hyoid, sterno-thyroid, and thyro-hyoid muscles, with their nerve -supply and blood- supply. The third layer delaminates to enclose the larynx and trachea and thyroid, the pharynx and oesophagus, the carotid sheath and its contents. The fourth layer delaminates to ensheath the rectus capitis anticus major and minor and longus colli muscles. First layer Second layer Third layer Fourth layer FIG. 24. DEEP CERVICAL FASCIA TRANSVERSE SECTION. (Schematic.) Dissection : 1. The temporal muscle and its aponeurosis or fascia. 2. The masseter muscle and its aponeurosis or fascia. 3. The sterno-cleido-mastoid and its fascial covering. 4. The trapezius muscle and its aponeurosis. 5. The zygoma, and its relations. 6. The temporal fossa and its contents. 7. The temporal ridge, its formation of three parts. Examine your work and answer this quiz : 1. Name the deep fascia covering the temporal muscle and give all its attach- ments. It is called the temporal fascia. It is attached to the linea suprema of the complete temporal ridge, and to the superior border of the zygomatic arch. 2. What does the complete temporal ridge consist of Y It consists of two parallel lines, having a frontal, a parietal, and a temporal portion. The aponeurosis of the muscle arises from the upper, the muscle itself from the lower line. 3. \Vhat structures occupy the superficial fascia, covering the temporal muscle / The superficial temporal arteries and their veins ; the auriculo-temporal nerve, a branch of the fifth cranial ; some temporal brandies of the seventh or facial nerve, and the lesser occipital nerve. THE HEAD AND NECK. 49 4. Wliat is the massctcric fascia ? The deep fascia covering the masseter muscle. It is of cervical derivation, being, with the parotid fascia, the upward continuation of the first layer of the deep cervical fascia. 5. Name the structures on tlie masseter muscle . The parotid gland in part; the pes anserinus of the seventh nerve ; Stenson's duct. In front of and under the anterior part of the muscle is some fat, called in the child the sucking pad. 6. Explain the relations and composition of the zygomatic arch. The arch is composed of a malar and a temporal portion. It has a superior border into which is inserted the temporal fascia ; an outer surface that is subcutaneous ; an inner surface and a lower border from which arises the masseter muscle. Under the arch' are found the coracoid process of the temporal bone, into which is inserted the temporal muscle ; the sigmoid notch, through which pass the arteries and nerves to the masseter muscle. 7. What structures lie on, and posterior to, the sterno-cleido-mastoid muscle ? The muscle is ensheathed by the first layer of the deep cervical fascia. (Fig. 24.) On the muscle lie the auricularis magnus and the superficial cervical nerves. The muscle is crossed by the external jugular vein. The spinal accessory nerve and all the superficial branches of the cervical plexus pierce the deep fascia at the posterior border of the muscle. These nerves are all in the occipital triangle. 8. Describe the superficial branches of the cervical plexus. (Fig. 22.) They are seven in number. The four ascending branches supply the neck and side of the head with sensation. The three descending branches supply the shoulder and upper third of the thorax. Their names are : 1. Lesser occipital parallels the sterno-cleido-mastoid muscle. It supplies the skin over the temporal muscle and the upper posterior part of the ear. 2. The mastoid branch, or second small occipital, supplies the skin over the insertion of the sterno-mastoid muscle into the mastoid process of the temporal bone. 3. The great auricular crosses the sterno-mastoid muscle to the ear, to which and to the skin over the the parotid it is distributed. 4. The superficial cervical nerve crosses horizontally the sterno-mastoid muscle. It supplies with sensation the whole front of the neck. It passes be- hind the external jugular vein. 5. Suprasternal. This nerve supplies the skin over the origin of the sterno- mastoid and over the manubrium sterni. 6. The supraclavicular supplies the skin over the pectoralis major to the nipple. It probably is this nerve that may account for the very diffuse pain over the head, neck, and shoulders in sore nipples of nursing mothers. 7. The supraacromial supplies the skin over the deltoid and clavicular por- tion of the trapezius muscles. The Masseter Muscle (Fig. 25). Cut this muscle at its origin from the malar process of the maxilla and the inner surface and lower border of the zygoma. As you turn the same down, notice the nerve- and blood-supply coming through the sigmoid notch. A little work with the forceps will remove the fat and develop the insertion of the temporal muscle into the coracoid process. Find the masseter inserted into the outer surface of the ramus of the mandible. So PRACTICAL ANATOMY. The Temporal Muscle (Fig. 25). Cut the aponeurosis of this muscle around the whole circumference of the temporal fossa. The aponeurosis will be attached to the zygoma in t\vo layers. Find between these two layers a small branch of the temporo-malar nerve. The nerve will do you no good ; but finding the same will be evidence of careful work. Turn the muscle itself down, after hav- ing removed the fascia, and see the deep temporal arteries. These supply the muscle with blood. They lie on the bone. They are branches of the internal maxillary. Find the deep temporal vein (Fig. 18) piercing the fascia above the zygoma, to join the superficial temporal. The sterno-cleido-mastoid muscle (Fig. 25) has two origins : (i) A sternal ; FIG. 25. MUSCLES OF THE FACE AND NECK. I. Frontal muscle. 2. Occipital muscle. 3, 3. Epicranial aponeurosis. 4. Temporal muscle. 5. Ketra- hens aurem. 6. Orbicularis palpebrarum. 7. Levator labii superioris et abeque nasi. 8. Dilator naris. 9. Compressor naris. 9'. Pyramidalis nasi. lo. Zygomatic minor, i-i. Zygomatic major. 12. Masseter. 13. Levator anguli oris. 14. Levator labii superioris. 15. Orbicularis oris. 16. Buccinator. i6 / . Depressor anguli oris. 17. Depressor labii inferioris. 18. Levator labii inferi- oris. 19. Sterno-mastoid. 20. Trapezius. 21. Digastric and stylo-hyoid. 22. Anterior belly of digastric. 23. Pulley for tendon of digastric. 24, 24. Omo-hyoid. 25. Sterno-hyoid. 26. Thyro- hyoid. 27. Mylo-hyoid. 28. Splenius capitis. 29. Splenius colli. 30. Levator anguli scapula'. 31. Scalenus posticus. 32. Scalenus anticus. (2) a clavicular. Its size, location, and extensive nerve-supply make it the most important muscle in the neck. These origins vary in size. In some cases you will find the clavicular part very small, in other cases very large. The sternal origin corresponds to the mastoid insertion ; the clavicular origin corresponds to the occipital insertion. If you will follow the cleft between the two heads, it will lead you to the junction between the occipital and mastoid. (Fig. 23.) Stemo-mastoid slicatli ( Fig. 24) is formed by a delamination of the first layer of deep cervical fascia. Cut through this sheath from end to end, just as you would separate two muscles. In fact, as. pointed out in the preceding paragraph, there are two muscles here, coalesced to form one. THE HEAD AND NECK. 5 1 NERVE-SUPPLY OF THE STERNO-MASTOID. This muscle, as you may now see, receives numerous twigs from the spinal accessory nerve as this nerve is passing through the muscle. It also receives nerves from the cervical plexus. Lift the muscle very carefully, and demonstrate these nerves on your own work. The Upper Attachments and Special Structures Formed by the First Layer of Deep Cervical Fascia (Fig. 26). The same fascia that covers the sterno-mastoid muscle is continued upward and forms special structures. You will now dissect and study these. Cut along the lower margin of the jaw to the symphysis rnenti. Avoid the facial artery and vein in front of the masseter muscle. Distribution of the Deep Cervical Fascia Above (Fig. 26). You now see this fascia extending from the sterno-mastoid muscle to the masseter muscle Capsule for submaxil- lary gland Sheath for di- gastric muscle Sheath for the de- pressors of the hyoid bone Mandibular attachment Masseteric fascia Parotid fascia Stylo-mandibular ligament Sheath for the sterno-mastoid The carotid sheath Sterno-mastoid, cut Trapezius Scalenus posticus Scalenus medius Scalenus anticus Fi<;. 26. SCHEME OF UPPKR ATTACHMENTS OF AND SPECIAL NAMKS FOR DEEP CERVICAL FASCIA. and parotid gland, forming their specific fasciae. You see it extending from the styloid process to the jaw as the stylo-maxillary ligament ; you see it forming a capsule for the submaxillary gland, and continuing forward to invest the anterior belly of the digastric muscle. The submaxillary gland is ensheathed by the first layer of deep cervical fascia. Observe the facial vein passing in front of the gland ; and the facial artery, perforating the deep fascia and passing behind the gland, or even through the same. WJiat nerves accompany the facial artery in its distribution to the face ? Sympathetic branches the nervi molles. They produce blushing and pallor of the face. 52 PRACTICAL ANATOMY. Are any other arteries accompanied by sympathetic nerves, in like manner, in this region / Yes, branches of the sympathetic accompany every branch of the external carotid artery. Hyperaemia then may occur in the distribution of the temporal, internal maxillary, and lingual arteries. The specific name for this physiological hyperaemia on the face is " blushing." Relations of the Sterno-cleido-mastoid Muscle. Review now carefully your dissection, and learn the relations of this muscle thus far exposed. See if your work shows the following points : 1. Did you demonstrate a sternal and clavicular origin and a mastoid and occipital insertion of the muscle ? 2. Did you find crossing or lying upon the sheath of the muscle the external jugular vein, the superficial cervical nerve, the great auricular nerve, and the Stylo-hyoid ligament BODY OF HYOID BONE Thyro-hyoid ligament Sterno-hyoid muscle Omo-hyoid Thyro-hyoid Crioo-thyroid Sterno-thyroid ISTHMUS TRACHEA Thyro-hyoid membrane Levator glandulee thyroide THYROID CARTILAGE PYRAMIDAL PROCESS OF THYROID BODY LEFT LATERAL LOBE FIG. 27. THYROID BODY, WITH MIDDLE LOBE AND LEVATOR MUSCLE. mastoid branch or second small occipital nerve ? Did you see emerging through the deep fascia, between the muscle and the trapezius, in the occipital triangle, the spinal accessory nerve and all the superficial branches of the cervical plexus ? Did you find the sheath of the muscle attached to the clavicle below ? Did you find the same derived from the first layer of the deep cervical fascia and continu- ous above with the masseteric and parotid fasciae ? with the stylo-maxillary liga- ment? with the submaxillary and digastric fasciae? Having done this, you may lift the muscle, observe its nerve-supply again, from the spinal accessory and cervical plexus, and study the posterior relations. Interior relations of t lie stcrno-clcido- mastoid muscle are : 1. The contents of the second layer of the deep cervical fascia. 2. The carotid sheath and its contents. This latter, you will remember, belongs to the third layer of deep cervical fascia. THE HEAD AND NECK. 53 THE MUSCLES AND NERVES IN THE SECOND LAYER OF DEEP CERVICAL FASCIA. 1 . The sterno-hyoid and omo-Jiyoid. 2. The sterno-thyroid and thyro-hyoid. 3. The nerve-supply of these the ansa liypoglossal loop. (Figs. 23 and 29.) Having turned the sterno-mastoid muscle and the fascia extending from it to the mid-line of the neck aside, you expose the sterno-hyoid and the omo-hyoid of this group. Figure 27 shows you the insertion of these two muscles con- jointly into the lower border of the body of the hyoid bone. Cut these two muscles one inch below this insertion, turn the lower part of the same forward carefully, and note the nerve-supply. These muscles must be handled very care- fully, in order to preserve them and also their nerves. The omo-hyoid arises from the superior border of the scapula for one inch. The sterno-hyoid arises Facial artery Lingual artery Supra-hyoid branch Infra-hyoid branch Superior laryngeal branch Crico-thyroid branch External carotid artery Ascending pharyngeal artery Internal carotid artery Sterno-mastoid branch Superior thyroid artery Common carotid artery Inferior thyroid artery FIG. 28. SCHEME OF SUPERIOR THYROID ARTERY. from the manubrium sterni. Trace out these origins at a later stage of your work. The sterno-cleido-thyroid is commonly called sterno-thyroid. This is inserted into the oblique line of the ala of the thyroid cartilage. (Fig. 27.) From here it is continued to the lower border of the outer third body, and the inner half of the greater horn of the hyoid bone as the thyro-hyoid muscle. The sterno-thyroid arises from the manubrium low down, and also from the clavicle. (Fig. 30.) Detach this muscle from its insertion and turn it down very carefully, and you will see the thyroid gland and its isthmus. The thyro-hyoid removed by detaching it at its origin, you expose the thyro- hyoid membrane, and see entering the same the superior laryngeal nerve and artery. (Fig. 28.) lOkvury Body 12 Nerve, - HypoglossaJ (Nonus or9' K ofWUis.) foSterno tljroul, Sthynut ma-lyout . FIG. 29. THE LOOP FORMED BY COMMUNICATING BRANCHES. Sterno-thyroid Triangularis sterni Sternal origin of diaphragm Costal origin of diaphragm Sterno-hyoid Triangular!* Bterni Transveraalis abdominis FIG. 30. 'I'm MTSCI.KS ATTACIIKD TO mi. HACK. 01 THE SIKRMM. 54 THE HEAD AND NECK. 55 THE NERVE-SUPPLY TO THE DEPRESSOR MUSCLES OF THE HYOID BONE. The group you have just dissected comes from a loop called the ansa hypoglossal. The expression cervico-Jiypoglossal would be a better term, as it would seem, as it expresses the derivation of the two elements composing the loop. (Fig. 29.) The loop is formed by the descendens hypoglossi, anastomosing with two communicating branches from the deep part of the cervical plexus. This loop is formed on the front part of the carotid sheath. From it branches are given off to the depressors of the hyoid bone. 1 . Give the boundaries of tJiat part of the neck most frequently operated on by the surgeon. Anteriorly, the mid- or mento-sternal line. Posteriorly, the anterior border of the trapezius muscle. Superiorly, the mandible and masto-mandibular line. Inferiorly, the clavicle and interclaviculaf ligament. 2. Name the cervical triangles and indicate tlieir importance. The submaxillary or supra-hyoid triangle is bounded above by the mandible and masto-mandibular line ; below, by the digastric and stylo-hyoid muscles ; in front, by the mento-sternal line. It contains : (i) The facial vessels and their sympathetic nerves ; (2) the submaxillary gland, its blood-vessels, nerves, and capsule ; (3) the submental and mylo-hyoid vessels and nerves ; (4) the stylo- mandibular ligament ; (5) the parotid gland and its contents ; (6) the vagus nerve, internal jugular vein, internal and external carotid arteries. The superior carotid triangle is bounded above by the digastric ; below, by the omo-hyoid ; behind, by the sterno-mastoid muscle. It contains: (i) The common carotid artery ; (2) the external carotid artery ; (3) the internal jugular vein ; (4) the vagus ; (5) spinal accessory, and (6) sympathetic nerves. 3. The inferior carotid or tracheal triangle is bounded above by the omo- hyoid, behind by the sterno-mastoid, in front by the mento-sternal line. It contains : (i) The thyroid gland and its blood-supply ; (2) the trachea; (3) the carotid sheath and contents ; (4) the inferior laryngeal nerve and inferior thyroid vessels. The three foregoing triangles lie anterior to the sterno-mastoid muscle. The two following ones lie posterior to the sterno-mastoid muscle. 4. The occipital triangle is bounded in front by the sterno-mastoid, behind by the trapezius, below by the omo-hyoid muscle. It contains: (i) The spinal accessory nerve; (2) the descending branches of the cervical plexus; (3) the transversalis colli vessels ; (4) a chain of lymphatic glands. 5. The subclavian triangle is bounded in front by the sterno-mastoid, above by the omo-hyoid, below by the clavicle. It contains: (i) The subclavian artery and vein ; (2) the brachial plexus ; (3) the external jugular vein ; (4) the nerve to the subclavian muscle. The student will please note that any arbitrary classification of contents is impossible. Structures are found to form partial contents of several triangles. The surgical triangles are to the modern surgeon about what totem poles would be to the city council. 6. Name the structures in the superficial fascia of the neck. (i) The platysma myoides muscle ; (2) the anterior, external, and posterior jugular veins ; (3) the inframandibular branch of the seventh nerve, and (4) the superficialis colli branch of the cervical plexus. 7. Name the layers of deep cervical fascia and give the contents of each. The first layer surrounds the sterno-mastoid muscle. 56 PRACTICAL ANATOMY. The second layer surrounds the hyoid depressors and their vessels and. nerves. The third layer surrounds the larynx, trachea, thyroid, oesophagus, common carotid artery, internal jugular vein, and vagus nerve. The fourth layer covers the rectus capitis anticus major and minor muscles and the longus colli. 8. What becomes of the first and second layers below? They are attached to the clavicle and sternum. 9. Give the origin and insertion of the temporal muscle. This muscle arises from the complete temporal ridge, from the temporal aponeurosis, from the temporal fossa, and is inserted into the coronoid process of the mandible. 10. Analyze the coronoid process. This has an outer and an inner surface, an anterior and a posterior border, a base, and an apex. 11. Of what does the complete temporal ridge consist ? It consists of frontal, parietal, and temporal portions. The ridge has a superior part for the attachment of the temporal fascia ; an inferior part for origin of the muscle. 1 2. What do you find in grooves on the deep surface of the muscle next the bone ? The deep temporal arteries branches of the internal maxillary artery for the supply of the muscle. 1 3. Analyse the zygomatic arch and tell what you find under fke same. The arcus zygomaticus is made up of the zygomatic processes of the malar and temporal bones. It has a superior border, into which is inserted the tem- poral fascia ; an outer surface, which is subcutaneous ; an inferior border and an inner surface, which are occupied by the origin of the masseter muscle. Under the arch are the coronoid and condylar processes of the mandible ; the sigmoid notch, transmitting the masseteric vessels and nerves ; the external pterygoid muscle ; and a considerable quantity of fatty connective tissue. 1 4. Describe the masseter muscle. This muscle arises ( i ) from the inferior border, anterior two-thirds, and (2) from the inner surface and posterior one-third of the lower border of the zygomatic arch. It is inserted into the external surface of the ramus. It is covered on its outer surface by the masseteric fascia, on which lie the pes anserinus, the parotid gland in part, and Stenson's duct. 1 5 . Describe the stcrno-clcido-mastoid muscle. This muscle has two origins a clavicular and a sternal ; and two insertions a mastoid and an occipital. It extends obliquely across the neck, dividing this region into an anterior and a posterior part. Its nerve-supply is from the spinal accessory and deep branches from the cervical plexus. It lies on the carotid sheath in part of its course, and along its posterior margin emerge the superficial branches of the cervical plexus. (Fig. 22.) 1 6. Name t/ic superficial brandies of tlic cervical plexus. The descending branches are the suprasternal, supraacromial, supra- clavicular ; the ascending branches are the great auricular, the small occipital, the lesser occipital, and the superficialis colli. Quiz on the Structures in the Second Layer of Deep Cervical Fascia. 1. Name the depressor muscles of t/ic liyoid. (i) The sterno-hyoid. (2) The omo-hyoid. (3) The sterno-thyroid. (4) The thyro-hyoid. 2. /fo:,< are tlicsc muscles cnshcathcd and from elicit are they separated in front and behind ? They are ensheathed by a delamination of the second layer of deep cer- THE HEAD AND NECK. 57 vical fascia. In front of them is the first layer of deep cervical fascia, which delaminates on the side of the neck to enclose the sterno-cleido-mastoid muscle. Behind these structures are the members making up a group ensheathed by the third layer of deep cervical fascia. 3. To what did you find the second layer of deep cervical fascia attached supe- riorly and inferiorly ? Superiorly it was attached to the hyoid bone ; inferiorly to the posterior part of the clavicle and manubrium. 4. From what source do the depressors of the hyoid bone receive their nerve- supply / From the ansa hypoglossal loop, descendens, and communicans noni. 5 . Hoiv is the ansa liypoglossal loop formed ? It is formed by the union of two branches from the deep cervical plexus with one branch from the hypoglossal nerve. 6. What are these communicating nerves called ? The one from the hypoglossal nerve is called the descendens Jiypoglossi ; the two from the cervical plexus are called the communicantes hypoglossi, and the loop formed by their union is the hypoglossal loop. j. Have these communicating nerves any synonyms in anatomical literature ? Yes, in the older texts they are called the descendens noni and communi- cantes noni. Under the classification of cranial nerves by Willis, there were nine pairs. The hypoglossal belonged to this ninth pair, hence the expressions nervus nonus, nervus descendens noni, and nervi communicantes noni. 8. Can you think of a compound word that would be more specific, and at the same time a more rational name than ansa hypoglossal ? Yes, the compound cervico-hypoglossal would express the anatomical parties to the compound, and would harmonize with our rules for writing compound words, by which such relations should always be expressed. 9. Where did you find this loop ? On the sheath containing the common carotid artery, pneumogastric nerve, and internal jugular vein. (Fig. 31.) The third layer of deep cervical fascia contains (Fig. 24) : 1. The thyroid body its nerve-supply and vessels. 2. The larynx and trachea, nerves and vessels. 3. The common carotid artery, vagus and internal jugular vein. 4. The external carotid artery and its branches in the neck. 5. The cervical stage of the internal carotid artery. 6. The hypoglossal nerve and its descending branch. 7. The cervical sympathetic cord and ganglia. 8. The arteries from the transverse aorta and their branches. 9. The phrenic nerve and anterior scalenus muscle. 10. The cervical plexus and its branches of origin. 1 1 . The bracldal plexus and its sheath. 12. The scaleni muscles anticus, medius, posticus. Dissection. Remove the group of muscles in the second layer of the cervical fascia, and examine the structures in the following order : i. Thyroid Gland (Figs. 27 and 28). This derives its capsule from the con- nective tissue in which it is developed. It has two lobes, connected by an isthmus. Its arteries are a superior thyroid, which you will take to its origin, the external carotid. This artery is attended by a vein. Note the anastomosis between the 5 58 PRACTICAL ANATOMY. superior thyroid and the inferior thyroid in the substance of the gland. The inferior thyroid artery is a branch of the thyroid axis of the subclavian. Note the crico-thyroid branch on the crico-thyroid membrane. Note also the superior laryngeal artery, the same artery you found when you removed the thyro-hyoid muscle : it accompanies the superior laryngeal nerve. The thyroid gland belongs to the class of ductless structures, as the spleen, thymus, and suprarenal capsules. An enlargement of this gland is called bronchocele ; in which case the isthmus may be divided or one-half of the gland removed. The nerves to the thyroid are of sympathetic derivation, from the middle and inferior cervical ganglia. The inferior thyroid veins you will trace to the left brachio-cephalic vein. -The superior and middle veins open into the internal jugular vein. These veins take their origin in a plexus of veins especially large on the posterior part of the gland. The carotid sheath is situated by the side of the trachea and larynx. In this sheath are the common carotid artery internally, the internal jugular vein externally, and the pneumogastric or vagus nerve between the two. The internal jugular vein is formed by the confluence of the dural sinuses. These sinuses receive their blood from the brain. The internal jugular veins are made up at the jugular foramina at the base of the skull. The ninth, tenth, and eleventh cranial nerves leave the cranial cavity with' the veins. In its course down the neck the jugular vein receives the superior and middle thyroid veins; and near their termination, they receive the external jugular veins. Behind the clavicle, you will see the internal jugular vein on each side unite with the subclavian vein. The result of this union is a large vein, called the innominate or brachio-cephalic vein. These latter of each side unite with the vena azygos major to form the descending vena cava. The right common carotid artery begins on the right side, at the bifurcation of the innominate artery. (Fig. 36.) This division occurs opposite the upper margin of the thyroid cartilage. The result of the division gives us an internal and an external carotid artery. Find to the inner side of the common carotid artery the larynx, trachea, thyroid gland, inferior thyroid artery, and recurrent laryngeal nerve. The left common carotid artery on the left side differs from that on the right as follows : It is given off in the thorax from the highest part of the arch of the aorta. (Fig. 36.) It has the same relations in the neck as the right common carotid. In the thorax the left common carotid artery is behind the manubrium sterni, the origins of the sterno-thyroid and sterno-hyoid muscles, the left brachio- cephalic or innominate vein, and the remains of the thymus gland. Behind the artery are the trachea, oesophagus, and thoracic duct. Internal to the artery are the innominate artery, the inferior thyroid veins, and remains of the thymus gland. External to the artery are the vagus nerve, the left lung, and pleura. The Glandulae Concatenatse. If the subject be tubercular, you may find the deep cervical lymphatics enlarged. They lie with the internal jugular vein, and may have contracted firm adhesions to the vein or artery or both. This seems to be the tendency of glandular tissue : (i) to penetrate or (2) to embrace. Instance the deep part of the parotid gland, penetrating the glenoid cavity and embracing the styloid process too ; the anterior part of the same gland embraces. in a V shape, the posterior border of the ramus of the mandible. Likewise, these lymphatics, when enlarged, embrace vessels, a circumstance which makes their removal often a very dangerous procedure. These glands you will find forming a continuous chain from the base of the skull to the apex of the thorax, where they are continuous with the mediastinai gland-chains. The pneumogastric nerve, also called the vagus, or par vagum, lies between I lie common carotid artery and internal jugular vein. Separate the connective tissue between the vessels and find the nerve, deeply located. This n r\e gives 77//1 HEAD AND NECK. 59 off in the neck (i) the superior laryngeal nerve to the larynx ; (2) the cervical cardiac branches ; (3) the pharyngeal branches ; (4) the recurrent laryngeal nerve. For the present remember this : The pneumogastric supplies the organs of voice and respiration with motion and sensation ; the organs of circulation and digestion with motion only. The internal carotid artery on each side begins at the bifurcation of the common carotid. Find this bifurcation and see whether it is opposite the thyroid cartilage or the hyoid bone. The internal carotid has four stages : i. The ccrrical to the base of the skull, from the bifurcation. Fiu. 31. VESSELS ANIJ NERVES OF THE HEAD AND NECK. I. Subclavian artery. 2. Subclavian vein. 3, 3. Common carotid artery. 4. internal jugular vein. 5. Anterior jugular vein. 6. Omo-hyoid muscle. 7. Sterno-hyoid muscle. 8. Trunk of pneumo- gastric nerve. 9. Hypo-glossal nerve. 10. Its terminal portion. if. Its descending branch. 12. Internal descending branch of cervical plexus. 13. Plexus formed by last two branches. 14. External carotid artery. 15. Superior thyroid artery and vein. 16. Lingual and facial arteries. 17. Facial artery and vein. 18. Occipital artery. 19. Anterior branches of the first four cervical nerves. 20. Superior laryngeal nerve. 2. The petrosal in the carotid canal in the petrosa. 3. The cavernous in the cavernous sinus on the lingula. 4. The cci'cbral at the base of the brain in the cranium. The cervical stage gives off no branches in the neck. The function of this artery is to take blood to the brain, eye, and nose. It assists the vertebral in forming the circle of Willis, by which circle the brain receives all its blood. Blood returns from the brain by the internal jugular vein. External Carotid Artery. This vessel begins at the bifurcation of the common carotid artery just mentioned. In some tubercular cases you will find 6o PRACTICAL ANATOMY. a large nest of enlarged glands here at the bifurcation. The following are the branches of the external carotid artery and their attendants : 1. The superior thyroid artery, vein, nerve, lymphatic. 2. The lingual artery, vein, nerve, lymphatic. 3. "\\e facial artery , vein, nerve, lymphatic. 4. The occipital artery, vein, nerve, lymphatic. 5. The posterior auricular artery, vein, nerve, lymphatic. 6. The ascending pharyngeal artery, vein, nerve, lymphatic. 7. The temporal artery, vein, nerve, lymphatic. 8. The internal maxillary artery, vein, nerve, lymphatic. NOTE. It has been pointed out in a foregoing paragraph that sympathetic nerves accompany every branch of the external carotid artery. Morris shows that the deep lymphatics of the head and neck roughly follow the course ot the deep arteries, and finally terminate in the glandular concatenatae previously described. Hence in vour dissection of the branches of the external carotid, Falato-gloasus Descending palatine arteri, Palato-pharyngeus TONSIL Ascending palatine branch of facial Tonsillar branch of dorsalis linguae Tonsillar branch of facial Stylo-glossuB - Dorsalis lingua artery Middle constrictor HYPOGLOSSAL NERVE Facial artery Posterior belly of digastric and stylo-hyoid Supra-hyoid branch SUP. LARYNGEAL K. Infra-hyoid branch Internal carotid artery Ronnie artery Q-enio-hyoid Anterior belly of digastric ur /rry Superior thyroid artery External carotid artery Common carotid arlrry FlG. 32. SCH KM K OK TI1K LlNCJUAI. ARTKRY. ,,: you will remember you can always find the vein corresponding to the artc the sympathetics may be found by treating the artery with ether and formaline ; the lymphatic glands can only be demonstrated when enlarged by disease. As t<> the lymphatic, I would urgently request the student to study carefully t schematic drawings of these vessels by Professor F. R. Sherwood, in Mor " Anatomy." Caution. Never use a cutting instrument in dissecting arteries. The fore or dissecting hook is all you need to divide the connective tissue. Handle veins with gentle touch ; they are very easily ruptured. Specific ] Dissection. The lingual artery: (i) find this vessel above the greater horn of the hyoid bone ; (2) a little below, and running parallel with, the hypoglossal nerve ; (3) passing behind the free margin of the hyo-glossus muscle to the tongue. (Fig. 32.) The Superior Thyroid Artery. (i) It is the first branch given off by the external carotid ; (2) it goes to the upper part of the thyroid gland ; (3) it gives off the superior laryngeal branch, which always accompanies the superior laryn- THE HI:, in AND XECK. 61 geal nerve ; (4) these structures, the superior laryngeal nerve and artery, pierce the thyro-hyoid membrane ; (5) the anastomosis is feeble with the opposite side ; free with the inferior laryngeal artery, and the distribution is to the gland and to the depressor muscles of the hyoid bone that cover the gland. (Fig. 28.) The facial artery: (i) often given off with the lingual; (2) note its deep course behind the hypoglossal nerve, the stylo-hyoid muscle, the digastric muscle, the parotid gland. It crosses the mandible in front of the masseter muscle. Its specific sympathetic nerves are called nervi molles. (Fig. 17.) The facial vein (Fig. 18), you will note, takes a superficial course. It lies in Anterior branch of pos- terior auricular I'osterior branch of pos- terior auricular PAROTID GLAND- L_, Sterno-mastoid, cut Auricular branch of occipital Rectus capitis lateralia Sl'IXAL ACCESSORY NER VE Posterior auricular Internal jttfjit/itr n'in Facial artery J/Y/'OflLOSXAL y. J.int/iirtl nrferi/ PNEUMOOASTRIC rio/' Itiiiroi'l Common carotid External branch of occipital Internal branch of occipital ComplexuB Priceps cervicis Superior oblique Trachelo-mastoid, cut Splenius capitis, cut Meningeal brancln'x Sterno-mastoid branch oj occipital Internal carotid Sterno-mastoid External carotid Trapeziua FIG. 33. SCHEME OF OCCIPITAL AND POSTERIOR AURICULAR ARTERIES. front of the structures behind which the facial artery passes. It opens into the external jugular vein. In your dissection show all the structures by which the facial artery and vein are separated in their cervical stage. Branches of the facial artery in the neck are : 1. To the stylo-hyoid, internal pterygoid, masseter, and buccinator. 2. Submaxillary branches four, to the submaxillary gland. 3. Submental artery to structures under the chin. 4. Tonsillar branches to the tonsil and tongue. 5. Ascending palatine branches to the soft palate. The Occipital Artery (Fig. 33). (i) Find the hypoglossal nerve passing 62 /'A' A CTICAL ANA TOM ) '. under and behind and external to it, to gain its place in front of the internal and external carotids ; (2) it passes behind the digastric, sterno-mastoid, splenius capitis ; (3) it gives off the arteria princeps cervicis, which anastomoses with the Stylo-, INFERIOR DENTAL NERVE CHORDA TYMPANI I / FACIAL NERVE j / / Internal maxillary artery Stylo-hyoid, turned up Digastricus, turned up Temporal artery glossus S'lliinental artery I Facial artery MYLO-HYOID NERVE LOWER JAW, TURNED UP Posterior auricular artern Internal jugular rein \ SECOND CERVICAL NERVE SPINAL ACCESSORY NERVE Eectus capitis auticua major Stylo-pharyngeus muscle SUP. CER. GANGL. OF SYMPATHETIC GLOSSO-PHAR. NERVE Sterno-mastoid, reflected Occipital artery Internal carotid Levator anguli scapulae THIRD CERVIC. NERVE DESCENDED HYPO- GLOSS I NER VE External carotid Inferior constrictor COMMl'N. HYPOGLOSS1 FOURTH CERV. NERVE Ascending cervical artery SPINAL ACCESSORY f PHRENIC NER VE Scalenus anticus Levator anguli scapula: FIFTH CERV. NER VE Scalenus medius CERVICAL I' LEX US DESCJSNDENS BRA NCH PNEVMOGA3TRIC / NER VE BRACHI.iL PLEXUS (SIXTH CERVICAL) Internal ja/jnlar rein Superficial ceii'ical artery Suprasca pnlar artery Serratus magnus Coraco-brachialis t \ Suprascapular artery given uff front ttiiril part nf snbclai inn Posterior scapular artery SUPRASCA PULA R NER VE Humeral thoracic artery SUB MA XI L LA R Y GA NGL10N G USTA TOR Y NER VE SUBMAXILLARY DUCT SUBMAXILLARY GLAND TONGUE HYPOGLOS. NERVE Rmiiite artery Qenio-hyo-glossus Sublinyual arteiy Lingual artery Artery affrcenitm LOWER JAW Genio-hyoid Hyo-glossus Liniinal artery Ifyoid branch Mylo-hyoid muscle Thyro-hyoid membrane SUPERIOR LARYN- GEAL NERVE Superior laryiigeal artery Thyro-hyoid Superior l/ii/njii! artery Omo-hyoid EX TERN A L LA R YN- GEAL NERVE THYROID GLAND Sterno-hyoid Coiiiiiitin carotid Sterno-thyroid Vertilnal artery Inferior thyroid artery . I nterinr j nyiilar vein CLAVICLE Verttbral rein KRACIIIAL PLEXl (SEVENTH CERVIC.) Siilic/nrinii artery Pectoralia major, reflected V Transverse cervical artery Subclavius, reflected BRACIIIAL I'LEXfS (EIGHTH CERVK'M.) Pectoral branch of acromial thoracic arteiy Posterior belly of omo-hyoid, drawn down Pectoral a minor Fic. 34. THE COMMON CAROTID, TIIK EXTKRNAI. AND I.MKKNAI. CAROTID, AND mi. Sruci \\i AKIKRIKS OK TIIK RICHT SIDE AND THEIR BRANCHES. (From a dissection by Dr. Alder Smith in the Museum of St. Bartholomew's Hospital.) deep cervical, a branch of the superior intercostal, and the vertebral artery. This anastomosis keeps up the collateral circulation, after ligation of the common carotid artery. '/'//A' HI 'I. ID AND NECK. 63 The posterior auricular artery arises high. You will find it behind the parotid gland. Trace it very close to the ear ; between the ear and the mastoid process of the temporal bone. The superficial temporal arteries are in the superficial fascia covering the temporal muscle. They are attended by the sensory auriculo-temporal branches of the fifth cranial nerve. Note the deep temporal vein piercing the temporal fascia above the zygoma. (Fig. 18.) The ascending pharyngeal you will find buried in connective tissue, lying between the internal and external carotid arteries. It arises from the external carotid near the bifurcation. It is the smallest branch of the external carotid. It is distributed to the pharynx and meninges. The internal maxillary will be dissected with the muscles of mastication and the fifth cranial nerve. (Fig. 51.) The Hypoglossal Nerve (Fig. 31). Find this nerve crossing the internal and external carotid arteries a little above the bifurcation of the common carotid artery. Note that this nerve lies a little distance above the lingual artery ; that the artery crosses behind the hyo-glossus muscle, the nerve in front of the muscle. The nerve gives off the following branches : 1. To the thyro-hyoid muscle. 2. To the stylo-glossus muscle. 3. To the hyo-glossus muscle. 4. To the genio-hyoid muscle. 5. To the genio-hyo-glossus muscle. 6. To the sterno-hyoid muscle. 7. To the omo-hyoid muscle. 8. To the sterno-thyroid muscle. 9. To the meninges ; recurrent branches. All these branches, except the meningeals, you can readily trace out. This nerve must not be mistaken for the superior laryngeal branch of the pneumo- gastric. Now compare the two nerves in their relation to the carotid arteries on your dissection. The result of section of this nerve will be considered when you dissect the tongue and outline its complete nerve-supply. Dissect the following muscles (Fig. 35) : 1. The digastric and its intermediary tendon. 2. The stylo-hyoid muscle. 3. The mylo-hyoid muscle. 4. The hyo-glossus muscle. I. Find the insertion of the stylo-hyoid muscle into the lower border of the body of the hyoid bone at the junction of the greater cornu and body of the hyoid bone. Study the relation of the intermediary tendon of the digastric to the aponeurosis of the stylo-hyoid muscle. Trace the origin of the stylo-hyoid muscle to the base and outer surface of the styloid process of the temporal bone. The Digastric has an anterior belly, that lies on the mylo-hyoid muscle, a posterior belly, that lies under the stylo-hyoid muscle just found, an intermediary tendon, and a suprahyoid aponeurosis. Carefully detach the anterior belly of the digastric muscle from the digastric fossa of the mandible, and as you pull this detached belly down, divide the connective tissue between this and the mylo- hyoid muscle. Notice the nerve-supply to the anterior belly of the digastric the mylo-hyoid branch of the inferior dental. The mylo-hyoid muscle is now in full view since you removed the anterior belly of the digastric muscle. It forms the floor of the mouth. It arises from the internal oblique line or mylo- hyoid ridge on the inner surface of the body of the inferior maxilla. It is in- serted into the mid-line of the neck into its fellow of the opposite side. This muscle will be studied when you dissect the mouth and tongue. 6 4 PR A CTICA L ANA TO. U ) . The Hyo-glossus Muscle (Pig. 32). This is the muscle that separates the hypoglossal nerve from the lingual artery. It arises from the body and greater and lesser cornua of the hyoid bone. It passes to the tongue. It is the most deeply located muscle in this region. The great branches from the transverse part of the arch of the aorta may be reviewed. In fact, you can not study them and their relations too much. The innominate has been seen dividing into the right subclavian and right common carotid. You may now dissect the branches of the subclavian artery and vein. The Subclavian Artery and Vein. The subclavian artery has three stages : 1. From its beginning to the inner border of the scalenus anticus. 2. The artery behind the scalenus anticus. (Fig. 36.) 3. From the scalenus anticus to the lower border of first rib. Stylo-glossus Hyo-glossus Mylo-hyoid Anterior belly _ of digastric Raplie of mylo- - byoid Thyro-hyoid Inferior constrictor Anterior belly of omo-hyoid Sterno-hyoid Sterno-thyroid - Scalenus posticus mft Posterior belly of omo-hyoid I.'K;. 3$. ANTKRIOR ANI> LATKKAI. CKKVICAJ. Mus< i i -. Find the scalenus anticus muscle inserted into the scalene tubercle of the first rib. In a groove in front of this tubercle find the ntbclavian vein ; behind the tubercle find the subclavian artery. Behind the artery find the scalcnns incdius muscle inserted into the first rib. Above the artery observe the anterior primary divisions of the fifth, sixth, seventh, and eighth cervical nerves and first dorsal nerve between the scalenus anticus and scalenus medius forming the brachial plexus, The subclavian arteries differ on the two sides ; the stages and branches, how- ever, are the same in each as to name. The first stage of the left subclavian is longer than the first stage of the right. The right subclavian artery begins behind the right sterno-clavicular articula- tion, at the bifurcation of the innominate artery. The artery lies very deeply. In THE HEAD AND NECK. 65 front of it are the skin, superficial fascia containing the platysma myoides, the clavicular head of the sterno-cleido-mastoid muscle, the sterno-hyoid and sterno- thyroid muscles. The phrenic nerve, the cardiac branches of the sympathetic nerve, the vagus nerve, the vertebral and internal jugular veins, cross this artery. Behind the artery is the neck of the first rib and the longus colli muscle and the recurrent laryngeal nerve ; below the artery is the pleura, against wounding which the greatest precautions should be taken in operations in this locality. The left subclavian artery is longer than the right ; it does not arch outward like the artery of the opposite side, but ascends vertically to the inner border of the scalenus anticus muscle and is situated more deeply in the thorax. In front PostSfu.ntii AnlSfunai FIG. 36. SCHEME FOR HEAD AND UPPER EXTREMITY. of the artery are the lung and pleura, the vagus, phrenic, and cardiac nerves, the left common carotid artery, internal jugular and vertebral veins, and left brachio- cephalic vein, the sterno-hyoid, sterno-thyroid, and sterno-cleido-mastoid mus- cles Behind the artery are the oesophagus, thoracic duct, inferior cervical gang- lion, longus colli muscle, anH vertebral column. To the outer side of the artery is the pleura ; to the inner side are the trachea, thoracic duct, and oesophagus. Branches of the subclavian artery : The internal mammary to anterior thoracic and abdominal walls. The vertebral to the brain and spinal cord and vertebrae. The superior intercostal to the first and second intercostal spaces. 66 PR A CTICAL ANA TO. M ) . The suprascatpular to the shoulder. The inferior tliyroid to the thyroid gland. The transvcrsalis colli. 1. The internal mammary (Fig. 36) is given off from the under part of the first stage of the subclavian artery. Its course, branches, anastomoses, and important relations are in the anterior thoracic walls, where you will find its description when you dissect that part. 2. The suprascapular artery (Fig. 37) is attended by a vein and nerve of the same name. It crosses the trunks of the brachial plexus, and is distributed to the supra- and infraspinati muscles. 3. The Inferior Thyroid Artery. Trace this artery behind the common carotid artery and sympathetic nerve. Very often the middle cervical ganglion of the sympathetic nerve rests on the inferior thyroid artery. Usually the artery Scalenus medius Scale-ius anticua and on it phrenic nerve Transverse CITI ifal artery Suprascn/inlnr nrtf.ry Sitbcliiiian artery conn OF BRA CIHA L f'LK.YUX, GIVING OFF MUSCULO- CUTAXEOUS ANT) OUTER HEAD OF MEDIAN NERVES Axillary artery IfUSCULO-SPIRA L NKR \'E T/ii/roitl mix Internal j ugii/ar vein Right common carotid artery PNEUMOGA8TR1C NERVE ieiK-fnirnt of iniiominatf, vein FIG. 37. THE SUBCLAVIAN VKSSKI.S. (From a dissection in the Hunterian Museum.) lies in front of the recurrent laryngeal nerve ; sometimes you will find the reverse is true. In operations on the thyroid gland isolate (i) the recurrent laryngeal nerve, (2) the sympathetic. The branches of the inferior thyroid artery : 1. The inferior laryngcal to the larynx. 2. Trachcal branches to the trachea. 3. Utsopltagcal branches to the oesophagus. 4. Jtram/ies to the depressor muscles of the hyoid bone. 5. Ascending cervical brandies to the muscles of the neck. The Superior Intercostal Artery (Fig. 39). This is given off from th< second stage of the subclavian artery. It gives off a communicating branch t( the first aortic intercostal, which you will find high in the thorax, when yoi THE HEAD AND NECK. 67 remove the pleura. The artery gives off its deep cervical branch, which inos- culates with the arteria princcps cervicis, a branch of the occipital. The anasto- mosis takes place between the complexus and semispinalis colli muscles. By Right anterior cerebral Internal carotid Right posterior cerebral Occipital Princeps cervicis External carotid Superficial branch of princeps cervicis Deep branch Ascending cervical Transverse cerrinil Posterior scapular Acromial branch Subscapular brunch ,- Supraspinous ^ branch Anterior circumflex Infraspimrtii branch Posterior circumflex Long thoracic Subicapulai Dorsal scapular fnfraieapttlar Subscapular Left anterior cerebral Anterior cotlMnunicutilig Posterior comma n icatiny Left posterior cerebral Basilar Anterior spinal Superior thyroid Inferinr (lit/mid Common carotid Thyroid axis Superior inten-ostai Illin>ltliliat! intrrriis'iil I.H't ennnnon carotid LfJ't subclavinn tjhiirt thoracic lii/ernal mammary Anterior intercostal I-'irxt aortic inter- costal Second aor/ic inter- com tal A n lerior in tcrcosla I Third aortic inter- costal FIG. 38. THE COLLATERAL CIRCULATION AFTER LIGATURE OF THE COMMON CAROTID AND Si ix I.AVIAN ARTERIES. (A ligature is placed on the common carotid and on the third portion of the subclavian artery.) this anastomosis the collateral circulation is carried on after ligature of the common carotid artery. (Figs. 38, 39, and 40.) The vertebral artery (Fig. 40) is given off from the second stage of the 68 PRACTICAL ANATOMY. subclavian. It passes through the foramina in the transverse processes of the cervical vertebrae, except the lower two, and through the foramen magnum, in the occipital bone, to assist the internal carotid artery in forming, by anasto- mosis, the circle of Willis. The artery is attended by a sympathetic plexus of nerves from the inferior cervical ganglion. The artery is found lying in the vertebral groove, at the junction of the lateral mass and posterior arch of the atlas in the suboccipital triangle, at the base of the skull. This triangle is bounded by the superior and inferior oblique and rectus capitis posticus major muscles. The roof of the triangle is the complexus muscle. Branches of the vertebral artery are as follows : 1. Muscular branches to the deep muscles of the neck. 2. Lateral spinal arteries to the spinal cord and meninges ; the bodies of the vertebrae also receive blood from these branches. Scalenus anticus muscle Deep cervical branch FIRST DORSAL NERVE FIRST INTERCOSTAL NER VE Subclavian artery SECONH I \TKRCOSTAL Anterior intercostal artery THIRD INTER- COSTAL NERVE Anterior intercostal artery Intercostal vessels qf third space SYMPA THE TIC SER VE INFERIOR CERVI- CAL GANGLION } Superior intercostal artery Arter ia aberrant Branch from first aortic intercostal Arteria aberrant Fint aortic intercostal artery Second aortic intercostal artery Intei costal vessels of fourth space FIG. 39. SCHEME OF THE SUPERIOR INTERCOSTAL ARTERY. 3. Anterior and posterior spinal branches that may be well seen when y( dissect the cord. 4. Posterior inferior ccrcbellar arteries. These are the largest arteries given off from the vertebral. They will be studied when we consider the structures seen on removing the brain. The two vertebral arteries unite, within the cranium, to form the basilar artery. This artery will be studied when you remove the brain. The transversalis colli is a branch of the thyroid axis. It gives off the posterior scapular artery, by which collateral circulation is established with the subscapular branch of the axillary artery in cases of ligation of the third stage of the subclavian artery. (Figs. 38, 39, and 40.) The scaleni muscles are three in number. You have already studied their insertion into the first and second ribs. You will now review the relation be- THE HEAD AND NECK. 69 tween the subclavian vein and artery on the outer surface of the first rib. You will again see the nerves that are to form the brachial plexus coming through between the scalenus anticus and scalenus medius muscles above the subclavian artery. You will find the phrenic nerve lying on the anterior surface of the scalenus anticus muscle. You will in time trace it between the subclavian vein and artery into the thorax, down in front of the root of the lung, to the diaphragm, and all the serous membranes continging the diaphragm, for distribution. Origin of the Scaleni Muscles. To aid the memory, remember the num- erals 3, 6, 3. The scalenus anticus arises from the anterior tubercles of the lower three transverse processes ; the scalenus medius from the lower six ; the scale- nus posticus from the lower three. The last two arise from posterior tubercles. Remember, scarcely any two dissections will show exactly the same origin ; I!iy the constriction of the pharynx would regurgitate through the nose, under THE HEAD AND NECK. 87 these conditions, this being the line of least resistance. Such cases of regurgita- tion are met as sequels of diphtheria. 9. Locate the tonsil. It is between the anterior and posterior pillars of the fauces ; it corresponds in position to the angle of the jaw ; the superior constrictor of the pharynx is external to it, while the internal carotid artery is fully one inch from it. It is the ascending pharyngeal artery, between the tonsil and the superior constrictor, and not the internal carotid artery that is in danger of being wounded in tonsil- lotomy. i o. Explain the mylo-hyoid nerve. It is a branch of the inferior dental, being given off while this nerve is between the ramus and spheno-mandibular ligament. It pierces the spheno- mandibular ligament, passes along the mylo-hyoid groove, and supplies the anterior belly of the digastric and the mylo-hyoid muscle. This nerve is a part of the motor root of the fifth, ensconsed in the sheath of the (sensory) inferior dental part of the fifth, given off from the Gasserian ganglion. (Fig. 53.) 1 1 . Name and explain fully the structures attacked to the styloid process of the temporal bone. (Fig. 44.) There are three muscles and two ligaments: (i) The stylo-hyoid muscle. This muscle arises from the back and outer surface of the styloid process, near the base. It lies above the posterior belly of the digastric muscle. Near its inser- tion into the body of the hyoid, at the junction of the body and greater horn, it bridges the intermediary tendon of the digastric. In its action it is synergistic with the posterior belly of the digastric, the two being supplied with motion by the seventh nerve. (2) The stylo-glossus muscle arises from the front and tip of the styloid process, also from the upper part of the stylo-mandibular ligament. It is inserted into the side and under surface of the tongue. Its action is to draw the sides of the tongue up to make the dorsum of this organ concave from side to side. (3) The stylo-pharyngeus arises from the base of the styloid process, opposite the stylo-hyoid. It is inserted, with the palato-pharyngeus, into the thy- roid cartilage, and also into and with the constrictors of the pharynx. (4) The stylo-maxillary or stylo-mandibular ligament will be seen in your dissection as a process of deep cervical fascia, a derivative of the third layer, between the masseter and internal pterygoid muscles. It separates the parotid from the submaxillary gland. It gives origin to one head of the stylo-glossus muscle. (5) The stylo-hyoid ligament extends, as a small elastic fibrous cord, from the tip of the styloid process of the temporal bone to the lesser cornu of the hyoid bone. It frequently becomes ossified. Occasionally it is of enormous size. 12. Describe tJie external pterygoid muscle. (Fig. 49.) This muscle has two origins and two insertions. The upper head arises from the under surface of the greater wing of the sphenoid bone, limited internally by the foramen ovale, transmitting the third division of the fifth nerve, and the fora- men spinosum, transmitting the great meningeal artery ; externally, the origin of this head is limited by the pterygoid ridge. The lower head arises from the greater part of the outer surface of the external pterygoid plate. The upper head is inserted into the interarticular fibro-cartilage ; the lower into the front of the condyle. The action of the muscle is to draw the condyle well forward, and with it also the interarticular cartilage. It also moves the jaw to the oppo- site side, and assists to some extent in opening the mouth. 13. Describe tlic internal pterygoid muscle. (Fig. 49.) It arises from the inner surface of the external pterygoid plate, and from the tuberosity of the palate bone. It is inserted into the inner surface of the ramus of the mandible, limited above by the mylo-hyoid ridge and inferior dental foramen. The action is to close the mouth and draw the jaw forward and to the mid-line. 88 PRACTICAL ANATOMY. The nerves to the pterygoid muscles are from the third division of the fifth nerve. (Fig. 53.) The blood-supply comes from the internal maxillary artery, second stage. (Fig. 51.) Describe the internal maxillary artery. (Fig. 51.) First Stage. Behind the neck of the mandible. In this stage it gives off: 1. The inferior dental artery to the inferior teeth. 2. The great meningeal artery to the dura and calvarium. 3. The small meningeal artery to the dura mater. 4. The deep auricular branch to external canal. 5. Tympanic, to the membrana tympani. Temporal Buccinator FIG. 52. THE TEMPORAL MUSCLE. The second stage of the artery gives off branches to muscles of mastication 1. Deep temporal branches to temporal muscles. 2. Buccal branch to the buccinator muscle. 3. Internal pterygoid branch to internal pterygoid muscle. 4. External pterygoid branch to external pterygoid muscle. 5. Masseteric branch, to the masseter. The second or pterygoid stage lies on the outer surface of the external ptery- goid muscle, under cover of the temporal muscle and the ramus of the mandible. The third stage of the artery gives off these branches : i. The posterior superior dental artery. This is confusing, and requires an explanation. The dental branches supply the teeth. They enter the posterior superior dental canals, through foramina on the posterior surface of the body of the superior maxilla. The alveolar branches supply the gums. Some branches supply the mucous membrane of the antrum ; these might be called antral branches. THE HEAD AND NECK. 89 2. The infraorbital artery enters the infraorbital canal in the floor of the orbit. It appears on the face as the infraorbital. It gives branches to the anterior teeth. These latter pass through the anterior superior dental canals in the anterior wall of the antrum. 3. Descending palatine passes through the posterior palatine canal, along the roof of the mouth, to the foramen of Stenson, where it anastomoses with the naso-palatine artery. It accompanies the anterior branch of Meckel's ganglion. 4. The spheno-palatine passes through the spheno-palatine foramen into the cavity of the nose. It divides into the naso-palatine branch to the septum, FIG. 53. SCHEME OF THE DISTRIBUTION OF THE FIFTH CRANIAL OR TRK;F.MINAL NERVE. Notice especially: (l) The recurrent branch from the Gasserian ganglion to the dura of the middle fossa and tentorium. (2) Filaments from the carotid plexus. (3) The motor root of the fifth nerve behind the ganglion, but independent thereof. (4) The formation of the otic, submaxillary, Meckel's, and the ciliary ganglion. which anastomoses with the descending palatine artery, and some external branches to the lateral walls of the nose. 5. The Vidian nerve passes through the Vidian canal with the Yidian nerve. It is distributed to the pharynx and Eustachian tube. 6. The pterygo-palatine passes through the pterygo-palatine canal. It is distributed to the upper part of the pharynx and Eustachian tube. Describe tJie inferior maxillary division of t/te fifth cranial nerve. It passes through the foramen ovale with the small meningeal artery. It gives off the following branches : i. Muscular branches to all the muscles of mastication. These accompany 7 9 PRACTICAL ANATOMY. muscular branches of the internal maxillary artery and take the name of the muscles. 2. The auriculo-temporal nerve. (Fig. 53.) The middle meningeal artery passes between the two roots of this nerve. This nerve gives an articular branch to the temporo-mandibular articulation. It does this in accordance with Hilton's law. It gives branches to the external auditory meatus and the membrana tympani, and is often responsible for ear-ache in children. It sends branches to the scalp, with the temporal arteries, and may be the terminus of visceral reflexes in the scalp. 3. The inferior dental nerve to (i) the teeth of the mandible ; (2) to the skin of the chin (mental nerve) ; (3) to the anterior belly of the digastric ; and (4) to the mylo-hyoid muscle, through the mylo-hyoid nerve. 4. The gustatory or lingual nerve, the great sensory nerve to the tongue. It anastomoses in the tongue with the hypoglossal and the glossal branch of the glosso-pharyngeal nerve. Special notice must be given this nerve, on account STYLOID PROCESS (i LOSSO-PHA R YN- GEAL NERVE HYPOOLOS8AL .v /;/. i '!: Occipital artery HUB MAXILLARY GANGLION DUCT OF SUBMAXILLARY GLAND Middle constrictor muscle l.ini/iKil iir/i'rt/ /-:.sr/.;.v/>/-;.y,s .\o.\j NERVB Fir.. 54. MUSCLES, VKSSKLS, AND NERVKS OK THK TON<;I ; K. of (i) the chorda tympani nerve; (2) the submaxillary ganglion ; (3) the ot ganglion. The chorda tympani nerve (Fig. 54) is a branch of the seventh cranial nerve. It passes through the tympanum. It leaves this cavity by the canal of Huguier in the petrous portion of the temporal bone. It passes between the two pterygoid muscles. It meets the lingual nerve, and accompanies this to the submaxillary gland. This nerve gives branches to the sublingual gland, the lingualis muscle, and the submaxillary ganglion. The Submaxillary Ganglion. (Fig. 54.) (rii'C location of the subma.villary ganglion. It is on the outer surface of the hyo-glossus muscle, attached to the gustatory or lingual nerve. The ganglion is about the si/e of a pin's head. Name the roots of the ganglion nn<1 give their source. 1 . Scnsorv root is from the gustatory nerve, a branch of the fifth nervr. 2. Motor root is from the chorda tympani, a branch of the seventh nerve. 3. Svmfwtltetic root is from the nervi molles the facial sympathetics. THE HEAD AND NECK. 9 1 Its branches are distributed to the mucous membrane of the floor of the mouth and to the submaxillary gland and its duct. The otic ganglion (Fig. 53) is on the inferior maxillary division of the fifth nerve. Its roots are : 1. Motor, from the inferior maxillary division of the fifth nerve. 2. Sensory, from the auriculo-temporal branch of the fifth nerve. 3. Sympathetic > from a plexus on the middle meningeal artery. Give tJie location and relations of the otic ganglion. (i) External to it is the inferior maxillary nerve ; (2) Internal to it is the circum- flexus (tensor) palati muscle ; (3) posterior to it is the middle meningeal artery. Aside from the three root communications previously given, has the otic ganglion any other communications ? Yes ; it communicates with the seventh or facial nerve and with the glosso- pharyngeal by the lesser petrosal nerve. ANTERIOR DENTAL MAXILLARY NERVE ORBITAL BRANCH MA X1LLA R Y NER I 'E MECKEUS GANGLION POSTERIOR DENTAL LOOP FORMED BY MIDDLE AND ANTERIOR DENTAL NERVES FIG. 55. THK MAXILLARY NERVE SEEN FROM WITHOUT. (Beaunis. ) To what muscles are the branches of the otic ganglion distributed ? To the tensor palati and tensor tympani. Describe the superior maxillary division of the fifth cranial nerve. (Fig. 55.) This nerve, a branch of the Gasserian ganglion, leaves the cranium by the foramen rotundum in the greater wing of the sphenoid bone. The nerve crosses the spheno-maxillary fossa, enters the orbit by the spheno-maxillary fissure, traverses the infraorbital canal in the floor of the orbit, appears on the face at the infraorbital foramen, and here communicates with the infraorbital branch of the seventh nerve to form the infraorbital plexus. Its branches are both numerous and important : i. The nasal, labial, and palpebral on the face. (Fig. 53.) Anterior superior dentals to incisor teeth. (Fig. 53.) Posterior superior dentals to molar teeth. (Fig. 53.) 4. Spheno-palatine branches to Meckel's ganglion. (Fig. 53.) 5. Temporo-malar are cutaneous to the cheek and temple. A recurrent meningeal branch to the dura. (Fig. 53.) 2. 3- 6. 92 PRACTICAL ANATOMY. Two CASES OF REFLEX PAIN. A Patient has Pain in tJic Auditory Canal On examination you find no local objective symptoms. Where may the real seat of the trouble be located ? The auditory canal is supplied by the auriculo-temporal branch of the fifth cranial nerve. The irritation may be sought for anywhere in the distribution of this nerve, but, logically, those parts of the fifth nerve which experience has proved are most liable to disease and injury should be interrogated first. We may venture the assertion that the teeth, nose, eye, tongue, and antruin of High- more represent about the order, in point of frequency. Here, then, is the specialist invoked, since a carious tooth, an irritated gum, a septal spur, eye strain, a lingual ulcer, or pus in the antrum of Highmore may be the immediate exciting cause of the pain in the auditory canal. Conversely, a patient may have a violent toothache, and examination may reveal neither exposed pulp nor irri- tated gum. Conservative dentistry in this case would refer a patient to other specialists, whose field of usefulness lies in the distribution of the fifth pair of cranial nerves, primarily or secondarily, since reflex pain may be primary and secondary. What is meant by primary and secondary reflex pain f The expression is a coinage, explained as follows : Where a carious tooth manifests pain in the ear, eye, nose, anywhere in organs supplied by the same nerve direct, this is called primary ; where, however, a carious tooth manifests pain in distant regions, not supplied by the fifth nerve, but connected therewith by communicating branches, this is called secondary. Let the following cases illustrate the point and apologize for the coinage : 1. A patient consulted a prominent dentist in this city for intractable pain in a molar tooth. Examination revealed no objective symptoms of disease. The patient was advised to consult other specialists in the primary radius of the fifth pair of nerves viz., the eye, nose, ear, or throat man. The patient disregarded the specific character of the advice, and consulted a specialist in the secondary radius of the fifth nerve, the gynaecologist, who removed an ovarian tumor. The pain in the molar did not return. 2. Hilton reports a case from Romberg of cough and vomiting which ceased only after a pruritus of the external auditory meatus was cured. The nerves concerned in this case were the vagus and the trigeminus. The general practitioner of medicine who facetiously disclaims confidence in reports of " toothache in the ear, and earache in an ovary," as he is wont to call such cases, is placing himself on record with those who a few years ago hooted at asepsis. Pain is a projectile, and specialists in medicine to-day are doing more than any one else to harmonize physiological speculations and anatomical nerve- distributions and nerve-communications, by furnishing clinical evidence of that line of least resistance which pain, as a projectile, must follow. The student of prac- tical anatomy is urged to give special attention to those parts of nerve-trunks recorded in the text-books as communicating branches, for upon these depends the rationale of reflexes, on which so much is said and written. The Glosso-pharyngeal Nerve (Fig. 54). You will find this nerve between the jugular vein and internal carotid artery. It lies above the superior laryngeal nerve, on the stylo-pharyngeus muscle and superior constrictor of the pharynx. It is distributed to the back of the tongue and to the pharynx. This nerve is deeply located. It can not be mistaken. It is the ninth cranial nerve. It leaves the base of the cranium by the jugular foramen with the tenth and eleventh nerves and the jugular vein. THE HEAD AND NECK. 93 THE MUSCLES OF MASTICATION. TJic muscles of mastication are the temporal, buccinator, the internal and external pterygoids, and the masseter. (Figs. 56 and 57.) These are the power- ful muscles that act on the mandible, by whose action the food is cut by the incisors, torn by the canines, and triturated by the molars. It would seem that the muscles that depress the jaw belong to the same category; hence we will consider them incidentally here, in detail in another section. The temporal muscle (Fig. 52) arises from the complete temporal ridge, from the temporal fossa, and from the under surface of the temporal fascia. It is inserted into the coronoid process of the mandible, as far forward as the last molar tooth. The muscle is triangular ; hence, according to rule, it will be found taking its nerve-supply near the apex. It derives its nerve-supply from the third division of the trigeminus. (Fig. 53.) In your dissection you find this muscle related superficially to the arcus zygomaticus, the temporal fascia, the temporal branches of the seventh nerve, the superficial temporal arteries and veins, and the auriculo-temporal branch of the fifth nerve. (Figs. 15-17.) Deeply the muscle is related to the temporal fossa and the external pterygoid muscle. The buccinator muscle (Fig. 62) arises from the alveolar processes above the upper and below the lower molar teeth of the upper and lower jaws respec- tively ; and from the pterygo-maxillary ligament. It is inserted into the outer part of the orbicularis oris. Its function is (i) to draw the corners of the mouth outward and backward against the teeth ; (2) to antagonize the tongue by per- mitting no food to be pushed by this organ beyond the dental arches, into the vestibule during mastication. The internal pterygoid muscle (Fig. '57) arises from the inner surface of the external pterygoid plate, from the tuberosity of the palate bone. It is inserted into the inner surface of the ramus of the mandible, as high as the inferior dental foramen and mylo-hyoid groove. The muscle is quadrangular ; hence, according to rule, it takes its nerve-supply in the centre. The action of the muscle is to close the mouth and draw the jaw forward and to the mid-line. Name the agents thai depress the lower jatv. The digastric muscle, the platysma myoides, and gravity. / ? 'liicJi muscles act on the mandible, to protrude the lower ja^iv ? The external pterygoid muscle and the superficial part of the masseter muscle. Hoiv is the mandible returned to its original position in the glcnoid ? It is drawn back by the posterior fibres of the temporal muscle, and by the deep fibres of the masseter muscle. \ \ liat are the ifiuscles of trituration ? The external pterygoids. They act alternately, drawing the mandible forward and to the opposite side : this movement produces trituration. WJiat is the function of the temporal, masseter, and internal pterygoid muscles ? They raise the mandible against the upper jaw with great force. Has the temporal muscle an independent, specific action ? Yes, its specific action is to accentuate incision. The quick snapping move- ment of the jaw is done by this muscle. What is meant by superficial and deep part of the masseter muscle / Your knowledge of the action of the masseter muscle on the mandible is imperfect without an understanding of these two parts : In reality each masseter is two muscles. Each part of the masseter muscle has a separate origin, separate function, separate insertion. One the superficial is strong, tendinous, and 94 PRACTICAL ANATOMY. active in assisting the external pterygoid muscle, in drawing the lower molars across the upper molars, in trituration of food ; the other the deep portion is weak, broad, muscular, and almost passive in assisting the posterior segment of the temporal muscle in bringing the mandible back to its position, preparatory to another movement of trituration. The specific origins and insertions of these separate parts of the masseter muscle make possible the separate physiological functions, as above indicated. Study them separately, as follows : The superficial part of the masseter (Fig. 56) muscle arises: (i) From Corrugatpr supercilii Fyramidalis Levator labii Buperioris alaequc nasi Levator labii Buperioris Compressor uarium Levator anguli oria Naso-labialis Depressor alae nasi Orbicularis oris Buccinator Depressor anguli oris Depressor labii inferioris Levator menti Mylo-hyoid Anterior belly of digastric Temporal Zygomaticus major Posterior belly of digastric Splenius capitis Stylo-hyoid Sterno-mastoid Levator anguli scapulae Scalenus anticus IMC. 56 '1'iiK. DKH-F.K LAYKK 01 nil-. Mr-ri.Ks 01 TMK FACE AND NKCK. the malar process of the superior maxilla by a strong tendon ; (2) from the anterior two-thirds of the lower border of the /.ygomatic arch. From this strong origin the fibres pass backward and downward to their insertion into the lower half and angle of the outer surface of the ramus. (Fig. 58.) The action is to draw the mandible forward. The synergist of this segment of the masseter is the external pterygoid. The deep portion of the masseter (Fig. 56) muscle arises : (i) From the inner surface of the /.ysj,omatic arch ; (2) from the lower border of the posterior THE HEAD AND NECK. 95 third of the zygoma. This portion is inserted into the upper half of the outer surface of the ramus. (Fig. 58.) Its action is to assist the posterior segment of the temporal muscle in drawing the mandible backward. The external pterygoid muscle (Fig. 57) originates when- and is hcnv inserted ? The function of this muscle is second to none, hence its bony and cartil- aginous attachments merit special notice. Here, as in the preceding case, there are in reality two muscles. They are, however, described as upper and lower heads of one muscle. The upper head arises from the pterygoid ridge on the outer and under surface of the greater ala of the sphenoid bone. Its specific insertion is, according to my experience, confined to the interarticular fibre-cartilage of the temporo-mandibular articulation. The function would seem to be to regulate the movements of this External ptefygoid Internal pterygoid FIG, 57. THE PTEKVCOID MTSCI.KS. cartilage to the sliding of the condyle forward on to the eminentia articularis when the mouth is opened. The only apparent use of the interarticular cartilage is, when the mouth is opened, to furnish a cup concavity for the condyle while this latter is gliding over the convex eminentia articularis. (Fig. 58.) A cracking noise on opening the mouth is frequently both a subjective and an objective symptom. This noise is beyond doubt produced by temporary paralysis of this part of the external pterygoid, the condyle overriding the margin of cartilage that normally should precede tire same. The rational treatment would seem to be fixation of the cartilage in the position it occupies when the mouth is open. Conclusion : The function of the upper head of the external pterygoid is to make tense and carry forward the interarticular fibre-cartilage. The function of the lower head is to most powerfully draw the jaw forward. The loiter /icad of the external pterygoid muscle arises from the outer surface 96 PRACTICAL ANATOMY. of the external pterygoid plate, except a small strip at its lower and front part It is inserted into the depression in front of the neck of the condyle. (Fig. 58.) The action of this head is to draw the condyle forward ; at the same time the upper head draws the cartilage forward. Concerning the noise patients frequently hear on opening the mouth, I would say I can not now recall ever having read or heard a rational explanation of its occurrence. The theory I advance above is more for the purpose of getting the student aroused to the necessity of learning the origins and insertions of the pterygoids than for mere theorizing. If I succeed even in this, the object of this paragraph will have been accomplished. I found a cadaver in which the crack- ing noise attended every time the mouth was passively opened. On dissection I found the cartilage had contracted inflammatory adhesions to the dome of the glenoid cavity. It was on this single case I founded the theory above advanced, in lieu of an explanation for those noises in the temporo-mandibular articulation concerning which every physician and dentist has been consulted by solicitous EMINENTIA ARTICULARIS POSTERIOR GLENOID TUBERCLE CORONOID PROCESS GLENOIO SYNOVIAL CAVITIES Interarticular flbro-cartil- age into which is in- serted the upper head of the external pterygoid Insertion of the lower head of the external pterygoid Insertion of the deep layer of the masseter muscle Insertion of the superficial layer of the masseter mus- cle FIG. 58. SCHEMATIC. TEMPORO-MANDIBULAR ARTICULATION. This is assumed to represent the normal relation of condyle of mandible, and interarticular cartilage to the * eminentia articularis when the mouth is closed. patients. A single case, however, is a mere bagatelle ; numerous cases by different observers will be necessary to give the theory scientific sanction. /// dislocation of the condyle of the mandible, what muscles must be overcome / Practically all. Theoretically, the posterior part of the temporal and the deep portion of the masseter. As a matter of philosophy, however, malposition of the head of a bone immediately sets up tonic contraction in all the muscles of the group, since pain in the joint is reported to the brain and contraction follows in all the muscles in the articular nerve circuit. See Hilton's law in the intro- ductory chapter. The temporal muscle has practically two portions : an anterior and a pos- terior. The latter pulls the jaw backward ; the former, acting alone, would pull the jaw forward. What are tJie propositions in tlic nerve -supply to the mitsc/cs of mastication f They are : i. Nerve-supply, sensory, both to the pulp of the teeth and to the gum THE HEAD AND NECK. 97 EMINENTIA ARTICULARIS Interarticular flbro- cartilage MANOIBULAR CONDYLE FIG. 59. SCHEMATIC. TEMPORO-MANDIBULAR ARTICULATION. This is assumed to represent relation of condyle and cartilage to eminentia articularis when the mouth is open. Here both condyle and cartilage slide forward on to the eminentia articularis ; the former by action of the lower, the latter by action of the upper, head. EMINENTIA ARTICULARIS Upper head of external pterygoid Lower head of external pterygoid GLENOID SYNOVIAL CAVITY CONDYLE UNATTENDED BY THE CARTILAGE ON THE EMINENTIA ARTICULARIS FIG. 60. SCHEMATIC. TEMPORO-MANDIBULAR ARTICULATION. This is assumed to' represent abnormal relation of condyle and cartilage to eminentia articularis in those cases where the nerve-twig that supplies the upper head of the external pterygoid muscle is paralyzed. A cracking noise on opening the mouth is a symptom. Here the cartilage remains back in the glenoid, there being nothing to pull it forward. The condyle slips over the thick margin and pro- duces the noise. 98 PRACTICAL ANATOMY. covering the same. This comes from the fifth cranial nerve, through dental and gingival branches respectively. 2. Nerve-supply, motor, to the muscles that elevate the jaw, and sensory, to the skin covering these muscles. This is from the fifth cranial nerve. 3. Nerve-supply, sensory, to the articulation moved by the muscles of mastication the temporo-mandibular articulation. This is from the auriculo- temporal branch of the fifth cranial nerve. This is explained by Hilton's law. 4. Nerve-supply, sensory, to the roof of the mouth. This is from the fifth through Meckel's ganglion. Also the sensory nerve-supply to the tongue. The greater part of this is from the fifth nerve through the lingual branch. 5. Nerve-supply to the inner nose, or that part of the system that selects food by the sense of smell. The sensory part of this is in great part from the fifth nerve, through Meckel's ganglion. The special sense of smell is from the olfactory or first cranial nerve. 6. Nerve-supply concerned in deglutition. Here a separate system, the digestive, begins, as is evidenced by a radical change in the nerve-supply. The muscles of the soft palate and pharynx are supplied by the pharyngeal plexus, the principal factors in which are the sympathetic and vagus nerves ; these nerves supply all the other organs of the digestive tract. What is the salivary system ? This system consists of the salivary glands, the parotid, the submaxillary, the sublingual, and their capsules, their nerve-supply, principally sympathetic, and their blood-supply. The latter is derived from the main artery of the region in which the glands are found. THE SOFT PALATE. 1. Prevents rcgurgitation of food into the mouth. (Fig. 64.) 2. Prevents passage of ingesta into the posterior nares. The structures concerned are the following : 1. The palato-glossus muscle. Nerve-supply, pharyngeal plexus. 2. The palato-pharyngeus muscle. Nerve-supply, pharyngeal plexus. 3. The levator palati muscle. Nerve-supply, pharyngeal plexus. 4. The tensor palati muscle. Nerve-supply, otic ganglion. 5. The azygos uvulae. Nerve-supply, pharyngeal plexus. To see the action of the palato-glossus muscle on the living subject, make prolonged effort to depress the tongue. When the patient is on the verge ot nausea, you will see the anterior pillars of the fauces spread out and draw the tongue closely under the palatine arch. This is, then, their action : during swallowing, after the bolus passes the initial part of the faucial passage, the tongue is forced under this arch to prevent regurgitation, while the constrictors of the pharynx are contracting on the food. During the same act the palato- pharyngei spread in such a way as to protect the upper pharynx and posterior nares, acting with the levator palati ; the circumflexus tightens the soft palate. The levator palati (Fig. 65) arises from the cartilage of the Eustachian tube, and from the under surface of the petrous portion of the temporal bone. It is inserted into the soft palate near the mid-line. The circumflexus (Fig. 65), or tensor palati, arises from the scaphoid fossa of the sphenoid bone. (Fig. i i.) The tendon passes around the hamular pro- cess of the internal pterygoid plate and is inserted into the median rap he of the soli palate. Some of its fibres are also inserted into the posterior margin of the hard palate. The azygos uvulae (Fig. 65) consists of some muscular fibres extending from the posterior nasal spine to the end of the a/ygos uvulae. (Fig. 1 1.) THE HI'. AH AND NECK. 99 //6>7t.' is the pharyngecU plexus formed and wJiat docs it supply f Tliis plexus is formed by the union of branches from 1. The superior cervical ganglion of the sympathetic. 2. The glosso-pharyngeal nerve, the ninth cranial nerve. 3. The pneumogastric or vagus nerve, the tenth cranial nerve. 4. The superior laryngeal nerve, a branch of the vagus. This plexus supplies the mucous membrane and muscles of the pharynx and all the muscles of the soft palate except the tensor palati, which receives its nerve-supply from the otic ganglion. The pharyngeal plexus may be seen on your dissection on the outer surface of the middle and inferior constrictors of the pharynx. What functions may be rationally attributed to the soft palate as a ivlwlc ? Its principal function seems to be to direct food to the stomach and protect the other cavities communicating with the pharynx from invasion by the food, (i) The anterior pillars of the fauces and the tongue prevent regurgitation into the mouth. (2) The posterior pillars of the fauces prevent regurgitation into the nose through the posterior nares. (3) The epiglottis protects the larynx. (4) The levator palati forms a temporary roof over the pharynx during deglu- tition, and thereby protects the Eustachian tube. (5) The tensor palati opens the Eustachian tube during deglutition. THE PHARYNX. This cavity is situated behind the nose, mouth, and larynx. It connects the mouth with the oesophagus. It is in communication with : 1. The larynx, which is guarded by the epiglottis. 2. The oesophagus, its downward continuation to the stomach. 3. The tympanum, through the Eustachian tube. 4. The nose, by the posterior nares. 5. The mouth, being partially shut off by the fauces. The proper muscles of the pharynx are: (i) The superior constrictor pharyngis. (2) The middle constrictor pharyngis. (3) The inferior constrictor pharyngis. (4) The stylo- pharyngis muscle. (5) The palato-pharyngeus muscle. The inferior constrictor you will find arising from (i) the cricoid cartilage ; (2) the oblique line of the thyroid; (3) the inferior cornu of the thyroid. It is inserted into the fibrous raphe. (Fig. 62.) The middle constrictor arises from the cornua of the hyoid bone, and from the stylo-hyoid ligament. (Fig. 62.) It is inserted into the median raphe, the fibres being disposed as follows : (i) The inferior fibres extend downward and are overlapped by the inferior constrictor ; (2) the superior fibres extend upward and overlap the superior constrictor in part ; (3) the middle fibres extend hori- zontally. (Fig. 62.) The superior constrictor muscle of the pharynx (Fig. 62) is pale and thin in comparison with the inferior constrictor. The reason of this will be appreciated when you understand the mechanism of deglutition. Growth is the correlative of function : the function of the inferior constrictor is vigorous con- traction, hence its roborous fibres ; on the other hand, the function of the superior constrictor is a retaining bag, hence its predominance of connective over muscular tissue. This muscle has the following origins, u;hk:U ae ,\vcl ; sl)<-un>iri figure. 62 : (i) From the internal pterygoid plate, lovcr tluVd, and .its ha.rii'.lar process; (2) IOO PRACTICAL ANATOMY. from the pterygo-mandibular ligament ; (3) from the posterior fifth of the mylo- hyoid ridge (Fig. 9) ; (4) from the side of the tongue. The muscle is inserted into the pharyngeal spine of the occipital bone and into the median raphe. Stylo-hyoid Ligament urn pharyngeum XI Posterior belly of digastric Sterno-mastoid Rectus capitis anticus major Etylo-pharyngeus Stylo-glossus Internal pterygoid SUPERIOR CERVICAL GANGLION Middle constrictor Cummon carotid artery Inferior constrictor GANGLION THYROIDEUM (VARIETY) THYROID GLAND Inferior thyroid artery Subclavian artery RECURRENT LARYNGEAL NER VE Internal carotid' artery RIGHT SYMPATHETIC Oceiii Hal artery Posterior belly of digastric DESCENDENS HYI'OGLOSSI Common carotid artery Sterno-mastoid TWIG OF RECURRENT LARYNGKAL TO PHARYNGEAL PLEXUS Thyroid axis INFERIOR CERVICAL GANGLION RECURRENT LARYNGEAL PLEXUS GULJE RIGHT PNEVMOGASTRIC Thoracic aorta Crus of diaphragm . FlG. 6l. DlSTRIHUTION OF THE PNEUMOGASTRIC Xl.KVK, VI K\VKI > 1 ROM 11K1IIND. (Krause.) What can you say of tlic structure of tlic pliaryn.v f It has three- coats : ;i ;,V/Y,VW.V,, vb.idi is continuous with the mucous membrane of the cavities-with which the ^haCrya>: communicates ; a muscular coat, special- THE HEAD AND NECK. 101 ized as constrictors and elevators of the pharynx to facilitate deglutition ; a fibrous coat, the pharyngeal aponeurosis, situated between the mucous and muscular coats, for strength and support. This is also called the pharyngeal aponeurosis. Between what two points docs the pharynx extend ? From the base of the skull to the cricoid cartilage. What is the pliaryngeal tonsil, and where is it located ? It consists of a mass of lymphoid tissue similar to that found in the tonsil. It is located on the back part of the pharynx, between the Eustachian orifices. INTERNAL PTERYGOID PLATE Superior constrictor Pterygo-mandibular ligament Stylo-hyoid ligament Middle constrictor Stylo-pharyngeua Inferior constrictor Thyroid cartilage Crioo-thyroid Crieoid cartilage FIG. 62. THE MUSCLES OF THE PHARYNX. Distinguish between pJiaryngeal fascia and pharyngeal aponeurosis. The fascia is behind the pharynx. It is the fourth layer of deep cervical fascia continued upward. The aponeurosis is one of the proper coats of the pharynx, located between the mucous and the muscular coats. What important structures do yon find between the superior and middle constric- tors of the pharynx ? The glosso-pharyngeal nerve and the stylo-pharyngeal muscle. (Fig. 63.) What do you find between the middle and inferior constrictors of the pharynx ? The superior laryngeal branch of the pneumogastric nerve, and the superior laryngeal branch of the superior thyroid artery. (Fig. 63.) 102 PR A (. 'TICAL ANA TOMY. Describe the /-'iistac/iia/t tube. It conveys air from the pharynx to the middle ear. You may see the pharyngeal orifice on the posterior wall of the pharynx, in line with the inferior turbinated bone. You will find the tympanic orifice in the anterior wall of the tympanum, forming the lower of the two compartments of the canalis musculo- tubarius. This you will understand when you dissect the middle ear and the petrous stage of the seventh nerve. The tube is an inch and a half long from the posterior wall of the pharynx to the anterior wall of the tympanum. The tube Fn;. 63. MUSCLES OF THE PHARYNX. I. Orbicularis oris. 2. Pterygo-maxillary ligament. 3. Mylo-hyoideus. 4. Os hyoides. 5. Thyro- hyoicl ligament. 6. Pomum Adami. 7. Cricoid cartilage. 8. Trachea. 9. Tensor palati. 10. Levator palati. II. Glosso-pharyngeal nerve. 12. Stylo-pharyngeus. 13. Superior laryn<*eal nerve and artery. 14. External laryngeal nerve. 15. Crico thyroideus. 16. Inferior laryngeal nerve. 17. Esophagus. has a bony part in the petrous portion of the temporal bone one-half of an inch long ; it has a fibro-cartilaginous part one inch long. Has the cartilaginous tube any practical importance as a guide in dissection f Yes ; it projects between the origins of the levator palati and tensor palati. Give the origins of t/ic levator palati and tlie tensor palati, and show their re- lation to tlic I'.iistac/iian tube. (i) The levator palati (Fig. 1 1) arises from the petrous part of the temporal bone and from the lower margin of the Kustachian tube. This muscle you find, then, behind the tube in dissecting, to the inner side. The tensor palati (Fig. 1 1 ) arises from the spine of the greater ala of the sphenoid, from the scaphoid fossa, and from the cartilage of the F.ustachian tube, and is in relation THE HEAD AND NECK. 103 with the external surface of the internal pterygoid plate internally, and with the internal pterygoid muscle externally ; the tendon turns inward around the hamular process, and is inserted into the aponeurosis of the soft palate and into the under surface of the horizontal plate of the palate bone. This muscle you will find in front of and to the outer side of the cartilaginous part of the Eustachian tube. Wliat is tlic salpingo-pJiaryngcus muscle ? A name by which those fibres of the palato-pharyngeus muscle are desig- nated that arise from the cartilaginous part of the Eustachian tube. Name all the muscles attached to the Eustachian tube. (i) The levator palati ; (2) the tensor palati ; (3) the salpingo-pharyngeus, or the Eustachian part of the palato-pharyngeus ; (4) the tensor tympani. FIG. 64. MEDIAN SECTION OK MOUTH, PHARYNX, AND LARYNX. Left nostril. 2. Upper lateral cartilage. 3. Inner portion of lower cartilage. 4. Superior turbinated bone and meatus. 5. Middle turbinated bone and meatus. 6. Inferior turbinated bone and meatus. 7. Sphenoid sinus. 8. Posterior nasal fossa. 9. Internal orifice or pavilion of Eustachian tube. 10. Velum palati. II, II. Vestibule of mouth. 12. Palatine vault. 13. Genio-glossus muscle. 14. Genio-hyoid. 15. Mylo-hyoid. 16. Anterior pillar of velum palati. 17. Posterior pillar. 18. Tonsil. 19. Circum vail ate papillse of tongue. 20. Cavity of larynx. 21. Ventricle. 22. Epiglottis. 23. Ilyoid bone. 24. Thyroid cartilage. 25. Thyro-hyoid membrane. 26. Posterior portion of cricoid cartilage. 27. Anterior portion. 28. Crico-thyroid membrane. Ho a' is the pharynx innervated ? From the pharyngeal plexus, located on the outer surface of the middle and inferior constrictor muscles and formed by the vagus, glosso-pharyngeal, and by branches from the superior cervical ganglion of the sympathetic. Give the attachments of the pharynx. The sphenoid (Eig. 11), the pharyngeal spine of the occipital, the petrous portion of the temporal, the Eustachian tube, internal pterygoid plate, posterior nares, mouth and larynx, prevertebral fascia, and oesophagus. The rectus capitis anticus major arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebrae. It is inserted into the under surface of the basi-occipital part of the occipital bone. 104 PRACTICAL ANATOMY. The muscle flexes the head. Its nerve-supply is from the first and second cervical. The rectus capitis anticus minor, a small muscle, arises from the upper part of the lateral mass in front of the articular process of the atlas. It is Fharyngeal apoueurosis Levator palati Tensor palati Azygos uvulae Hamular process TONGUE EUSTACHIAN TUBE Levator palati Palato-pharyngeus Superior constrictor Crico-arytenoideu posticua EPIGLOTTIS Thyroid cartilage Cricoic" cartilage TRACHEA ISOPHAGUS FIG. 65. VIKW OF MUSCLES OF SOFT PALATE, AS SKEN FROM WITHIN THE PHARYNX. (Modified from Bourgcry.) inserted into the basilar process of the occipital bone, posterior to the preceding muscle. The muscle acts synergistically with the rectus capitis anticus major. The rectus capitis lateralis arises from the lateral mass of the atlas. It is inserted into the jugular process of the occipital bone. Its action is to flex the head laterally. This and the preceding muscle are supplied by the first cervical nerve. THE HEAD AND NECK. The longus colli. Origin. i. From bodies of sixth and seventh cervical and first, second, and third dorsal. Insertion. 2. Into the bodies of the second, third, and fourth cer- vical. w ( Origin. I. Anterior tubercles of transverse processes of third, fourth, and fifth cervical. " I Insertion. 2. Tubercle on anterior arch of the atlas. Rsetus capitis lateralis Rectus capitis anticus major Origin of rectus capitis anticus major Scalenus medius Scalenus antlous Scalenua posticus Rectus capitis later- alis Rectus capitis anti- cus minor Intertransyersalis anterior Intertransversalis posterior Longus colli Insertion of scalenus anticus Scalenus medius Scalenus posticus FIG. 66. THK MUSCLES OF THE FRONT OF THE NECK. '* S f Origin. i. Bodies of first, second, and third dorsal vertebrae. . 2* < Insertion. 2. Anterior tubercles of transverse processes of fifth and C iJ I . , J Q i. sixth cervical. These muscles are supplied by the anterior divisions of the cervical nerves. The action is evident : flexion direct, lateral, or combined in rotation. io6 PRACTICAL ANA TOM}. THE LARYNX. The upper part of the respiratory tract is called the larynx. Its downward continuation into the neck and thorax is the trachea. The essential organ of voice is a vocal cord on each side of a chink called the rima glottidis. The greater part of the larynx is set aside as a protective for the delicate vocal cords. BODY OF HYOID BONE Thyro-hyoid ligament Cartilage triticea Foramen for superior laryngeal nerve Median portion of thyro- hyoid membrane SUPERIOR CORNU OF THYROID CARTILAGE MEDIAN NOTCH OF THYROID CARTILAGE Fomum Adami OBLIQUE LINE OF THYROID CARTILAGE Crico-thyroid membrane INFERIOR CORNU OF THYROID CARTILAGE THIRD RING OF TRACHEA OBLIQUE LINE BELOW SUPERIOR TUBERCLE WING OF CARTILAGE BEHIND OBLIQUE LINE OBLIQUE LINE ABOVE INFERIOR TUBERCLE ANTERIOR BORDER OF INFERIOR CORNU FIG. 67. FRONT VIEW OF THE CARTILAGES OK THE LARYNX. (Modified from Bourgery and Jacob.) POSTERIOR SURFACE OF ARYTENOID MUSCULAR EXTERNAL ANGLE Crioo-arytenoid joint POSTERIOR SURFACE OF CRICOID CARTILAGE Longitudinal fibres of oesophagus CORNICULUM LARYNCIS Arytenoideus muscle Crieo-arytenoideus posticus muscle Crioo-arytenoideus posticus muscle ARTICULAR SURFACE FOR INFERIOR CORNU OF THYROID CARTILAGE FIG. 68. BACK VIEW OF THE CRICOID AND AKYTKNOID CARTII.ACKS. (Modified from Bourgery and Jacob.) A minor part of the larynx is set aside to move the vocal cords. To gain a comprehensive idea of the larynx in your dissection, you must find on your dissection the following structures : 1. The thyroid cartilage and hyoid bone. (Fig. 67.) 2. The thyro-hyoid membrane and median notch of thyroid cartilage. THE HEAD AND NECK. 107 3. The cricoid cartilage and crico-thyroid membrane. (Fig. 67.) 4. The arytenoid cartilages surmounting the cricoid cartilages. 5. The epiglottis in the retiring angle of the thyroid cartilage. (Fig. 69.) 6. The mucous membrane of the larynx. 7. The superior laryngeal nerve of the vagus nerve. (Figs. 63 and 71.) 8. The inferior laryngeal nerve (the recurrent branch figure 71) of the vaeus. GREATER CORNU OF HYOID BONE BODY OF HYOID BONE Thyro-hyoid ligament EPIGLOTTIS Median notch Origin of thyro-epiglottic ligament POSTERIOR EDGE OF THYROID CARTILAGE Origin of thyro-aryte- noideus muscle INFERIOR CORNU SMALLER CORNU OF HYOID BONE CARTILAGO TRITICEA SUPERIOR CORNU OF THYROID CARTILAGE RIGHT ALA OF THYROID CARTILAGE False vocal cord True vocal cord Origin of thyro-epiglot- tideus muscle FIG. 69. POSTERIOR VIEW OF THYROID CARTILAGE WITH EPIGLOTTIS. 9. The superior laryngeal artery, a branch of the superior thyroid artery. (Fig. 28.) 10. The sympathetic nerve with the laryngeal arteries. 1 1. The inferior laryngeal artery, a branch of the inferior thyroid. (Fig. 28.) 1 2. The vocal cords true and false. 13. The ventricle, the space between true and false cords. Thyro-arytenoideus muscle Attachment of erico-thyroid muscle ANTERIOR SURFACE OF ARYTENOID CARTILAGE Cut edge of eapsular ligament Lateral crico-arytenoid muscle MUSCULAR EXTERNAL ANGLE OF ARYTENOID CARTILAGE Lateral crico-aryteuoid muscle CRICOID CARTILAGE FIG. 70. FRONT VIEW OF THE CRICOID AND ARYTENOID CARTILAGES. and Jacob.) (Modified from Bourgery 14. The intrinsic muscles of the larynx. 15. The relation of the epiglottis to the tongue. The thyroid cartilage (Fig. 67) has two alae united in the mid-thyroid line. The result of this union gives us the pomum Adami in front, and the retiring or receding angle of the thyroid cartilage behind. (Fig. 69.) The former is a guide in surgical operations on the larynx and trachea ; the latter is of great im- portance in learning the anatpmy and physiology of the vocal cords. Along the io8 PRACTICAL ANATOMY. superior border of the thyroid cartilage, in the mid-line, you will see the thyroid median notch. Each thyroid ala has a superior cornu and an inferior cornu. The inferior cornu articulates with the cricoid cartilage, forming the crico-thyroid articulation. (Fig. 67.) The superior cornu gives attachment to the lateral thyro-hyoid ligament. The outer surface of the ala has an oblique line, limited above and below by a superior and inferior tubercle respectively. (Fig. 67.) The retiring angle of the thyroid cartilage (Fig. 69) gives origin to: (i) The epiglottis ; (2) the false vocal cords ; (3) the true vocal cords ; (4) the thyro-arytenoid muscle ; (5) the thyro-epiglottideus muscle. The cricoid cartilage (Figs. 68 and 70) forms, as you will see, a complete ring. It is very narrow in front ; quite wide behind. The arytenoid cartilages GREATER CORNU OF HYOID BONE CARTILAOO TRITICEA SUPERIOR CORNU OF THYROID CARTILAGE BRANCH TO LATERAL CRICO ARYTENOID AND TBYRO-ARYTE- .VOID MUSCLES BKANCB JOINING THE SUPERIOR LARYN- GEALKERVR Crico-arytenoldeu* posticus muscle INFERIOR CORNU OF THYROID CARTILAGE FORAMEN C/EOUM BASE OF TONGUE EXTERNAL LARYN- GJKAL NERVE INTERN A L LA R YN- <;I:AL NERVE Cut edge of thyro- hyoid membrane AryteuoideuB muacle RECURRENT LARYNOEAL NER VJ FIG. 71. NERVES OF THE LARYNX. (Posterior view.) rest upon the superior border of the cricoid, behind, forming a movable articula- tion, called the crico-arylenoid. The arytenoids are small. You must learn the following geometrical de- scription of the arytenoids before you can dissect the larynx understandingly, much less understand the action of the arytenoids : Apex, obtruncate and points backward and inward. Base, articulates with the cricoid cartilage. (Fig. 68.) Posterior surface is occupied by the arytenoicleus muscle. (Fig. 68.) Anterior surface for attachment of false cords and thyro-arytenoideus. (Fig. /o.) Internal surface is covered by mucous membrane. Anterior angle, processus vocalis for insertion of true vocal cord. (Fig. 68.) THE HEAD AND NECK. 109 External angle for insertion of posterior and lateral crico-arytenoid muscles. The intrinsic muscles are as follows : 1. The thyro-arytenoideus. (Fig. 70.) 2. The crico-arytenoideus lateralis. (Fig. 70.) 3. The crico-arytenoideus posticus. (Fig. 69.) 4. The arytenoideus. (Fig. 69.) 5. The crico-thyroid. (Fig. 27.) The intrinsic muscles and the mucous membrane are supplied by (i) the superior laryngcal branch of the pneumogastric ; (2) the inferior laryngeal branch of the pneumogastric ; (3) the sympathetic nerves accompanying the superior and inferior laryngeal arteries ; they take the name of the arteries. The superior laryngeal nerve (Fig. 71) supplies the mucous membrane and the crico-thyroid muscle. Epiglottis Cut edge of hyo-epiglottidean ligament SECTION THROUGH BODY OF HYOID BONE Peri glottis Cut edge of thyro-hyoid membrane Thyro-epiglottideus muscle SECTION OF THYROID CARTILAGE Thyro-arytenoideuB muscle Crioo - arytenoideua lateralis muscle (the pointer crosses erieo-thyroid membrane) CRICOID CARTILAGE Aryteno-epiglottidean fold Aryteno-epiglottideus muscle Arytenoideus muscle Crleo-arytenoideus postious Recurrent laryngeal nerve FIG. 72. SIDE VIEW OF THE MUSCLES AND LIGAMENTS OF THE LARYNX. The inferior laryngeal supplies the remaining muscles. The false vocal cord extends from the retiring angle of the thyroid cartilage (Fig. 69) to the anterior surface of the arytenoid cartilage. (Fig. 70.) The true vocal cord extends from the retiring angle of the thyroid cartilage (Fig. 69) to the anterior angle of the arytenoid cartilage. (Fig. 70.) The chink, or rima glottidis, is the space between the two true vocal cords. This chink consists of two parts a respiratory or posterior and a vocalizing or anterior. The thyro-arytenoid muscle (Fig. 69) extends from the retiring angle of the thyroid cartilage to the anterior surface of the arytenoid cartilage. (Fig. 70.) The action of this muscle is to pull the arytenoid cartilage forward and thereby relax the vocal cords. The arytenoid muscle (Fig. 71) extends from the posterior surface of one no PRACTICAL ANATOMY. to that of the other arytenoid cartilage. It approximates the vocal cords by drawing the arytenoids together. The crico-arytenoideus lateralis (Fig. 72) arises from the upper border of the side of the cricoid cartilage. It is inserted into the external angle of the base of the arytenoid cartilage. The action is to draw the vocal cords together and close the glottis. The crico-arytenoideus posticus arises on the posterior part of the cricoid. It is inserted into the outer angle of the base of the arytenoid cartilage. This muscle draws the vocal cords apart, and thereby opens the glottis. The crico-thyroid muscle arises from the side of the cricoid cartilage. It is inserted into the lower corner of the thyroid cartilage. It tightens the vocal cords. Describe the superior laryngeal nerve. (Fig. 71.) It is a branch of the ganglion of the trunk of the pneumogastric nerve. It passes behind the internal and external carotid arteries. It is joined by com- municating branches from the sympathetic nerve and the pharyngeal plexus. It divides into an internal and an external branch. The external branch pierces the inferior constrictor of the pharynx near the lower border of the thyroid cartilage (Fig. 63), and is distributed principally to the crico-thyroid muscle ; some few filaments are distributed to the mucous membrane. The internal division, in company with the superior laryngeal artery, passes under the thyro-hyoid muscle (Figs. 27 and 71), pierces the thyro-hyoid membrane, and is distributed to the mucous membrane, communicating here with the recurrent laryngeal nerve. (Fig. 71.) Describe the course of the recurrent laryngeal nerves. (Fig. 71.) The nerve of the right side is given off from the pneumogastric in front of the first stage of the subclavian artery. It passes upward, under, and behind the subclavian artery, then behind the common carotid to the side of the trachea. It lies in a fatty groove between the trachea and oesophagus, and, in company with the inferior laryngeal artery, passes upward, under the inferior constrictor of the pharynx, to the larynx. It is distributed to all the intrinsic muscles of the larynx except the crico-thyroid. The recurrent laryngeal nerve of the left side is given off from the pneumogastric in front of the transverse part of the aortic arch, passes under this vessel behind the obliterated ductus arteriosus, and gains the fatty space between the trachea and oesophagus, and has the same sub- sequent course and distribution as the nerve on the right side. In their course between the oesophagus and trachea these nerves give off branches to these conduits. Describe the blood-supply of the larynx. (Fig. 28.) The superior laryngeal artery is a branch of the superior thyroid. It accom- panies the superior laryngeal nerve, piercing with this nerve the thyro-hyoid membrane. The inferior laryngeal artery is a branch of the inferior thyroid. It passes behind the inferior constrictor of the pharynx with its accompanying nerves. Describe the trachea. It is an air conduit, extending from the larynx to the tracheal bifurcation, where the bronchial tubes begin. Compared to the vertebral column, in front of which the trachea lies, it extends from the fifth cervical to the fifth thoracic verte- bra. It is one inch in width and five inches long. The structure of 'the trachea fits it admirably for its specific double function (i) of transmitting air inward and (2) of extruding both air and accumulated mucus, bearing crude inhaled impurities. Imperfect rings of cartilage, held together by fibro-elastic membrane possessing some muscular fibres, a rich nerve- ami blood-supply, and a lining of mucous membrane, are the anatomical tissues THE HEAD AND NECK. in that specially qualify the trachea for its important duty. The front part of the trachea is round, the back part flat. The space between the ends of the imper- fect rings of cartilage behind is filled by the musculus trachealis. This consists of transverse and longitudinal unstriped fibres. The arrangement of these is such as to set up a vermicular movement in the trachea when expectoration occurs. The nerve-supply of the trachea comes from the vagus and also from the recurrent laryngeal, a branch of the vagus, as this latter nerve lies in the fatty groove between the trachea and oesophagus ; and from the sympathetic, which latter nerves accompany the tracheal arteries, and take the same name. The blood-supply of the trachea comes from the inferior thyroid artery, a branch of the thyroid axis of the subclavian artery. (Fig. 36.) The veins join the thyroid plexus of veins. Of the thyroid veins, you will remember, the right opens into the right innominate, the left into the left innominate vein. Each of these has valves where it becomes tributary to the larger vessel. These thyroid veins communicate on the trachea. These are the troublesome vessels in low tracheotomy. Relations of the Trachea. If you will review your dissection, you will find in front of the cervical part of the trachea the isthmus of the thyroid gland (Fig. 27), the inferior thyroid veins, the sterno-hyoid and sterno-thyroid muscles (Fig. 27), the deep cervical fascia, superficial fascia, and skin. Behind, the trachea is in rela- tion with the oesophagus. On each side are the common carotid arteries, the infe- rior thyroid artery, the recurrent laryngeal nerve, and the lobes of the thyroid gland. (Fig. 31.) The thoracic part of the trachea, as you will see at a later stage of your work, is covered by the manubrium sterni, the remains of the thymus gland, the left brachio-cephalic vein, the aortic arch, the innominate and left com- mon carotid arteries, and the deep cardiac plexus. Posteriorly is the oesophagus, and laterally the vagus nerves are on each side. THE NASAL FOSS.E INTERNAL NOSE. Dissection. With a sharp saw cut through (i) the symphysis of the mandible. Then take a sharp knife and cut through the tongue from base to tip in the mid- line, as far forward and downward as the hyoid bone. (2) Let an assistant hold the divided halves of the mandible apart, while you saw through the mid-line of the remainder of the face. (Fig. 64.) Precaution : Before you make the latter cut, observe to which side the septum nasi is deflected ; cut on the opposite side, so as to have the septum intact for study. The cuts have placed before you for study the mouth and nasal fossae. Very little dissection in addition to that already done is necessary. The nasal fossae have the following geometrical parts : 1 . Roof, formed by the nasal bones, the nasal spine of the frontal bone, crib- riform plate of the ethmoid, the under surface of the body of the sphenoid. 2. A floor (Fig. 74), formed by the hard and soft palate, covered by mucous membrane. The hard palate is formed by the palatine process of the superior maxilla and the horizontal part of the palate bone. 3. An inner wall (Fig. 74), formed by the septum nasi, covered by mucous membrane. The septum nasi is composed of (i) thevomer ; (2) the vertical plate of the ethmoid ; (3) the cartilaginous septum quadrangular in some, triangular in other cases. The outer surface is formed by the nasal bones, the nasal process of the 112 PR A CTICAL ANA TO MY. superior maxilla, the lachrymal, ethmoid, inner surface of superior maxilla, in- ferior turbinated, vertical plate of palate bones, and inner surface of pterygoid PTERYGO-PALATINE CANALS VIOIAN CANAL PTERYGOIO FOSSA EXTERNAL PTERYGOID PLATE TUBEROSITY OF PALATE BONE FORAMEN OVALE INTERNAL PTERYGOiD PLATE HAMULAR PROCESS SPINE OF PALATE OR POSTERIOR NASAL SPINE FIG. 73. THE POSTERIOR NARES. NASAL BONE Frontal sinus Sphenoidal sinus UPPER LATERAL CARTILAGE Groove between septa! and upper lateral cartilage LOWER LATERAL THICKENED BORDER OF CARTILAGE RESTING i \ Pouch at uprer UPON ANTERIOR NASAL SPINE Incisive papilla \ extremity of Sten- SEPTAL CARTILAGE 8on ' 8 canal ORIFICE OF EUSTACHiAN TUBE SOFT PALATE FIG. 74. SECTION SHOWING BONY AND (.'AIM -11 .ACINOI s SKITCM. The dotted line indicates the course of the anterior palatine canal. process of the sphenoid bone. This surface is covered by mucous membranr. This must be studied on the dry skull. The anterior narcs is the inlet to the nose from the external world. The THE HEAD AND NECK. IT 3 posterior nares is the opening into the pharynx. (Fig. 73.) Notice: On the outer wall, and even forming part of the same, are the three turbinated bones. Study figure 74. Remove the mucous membrane from the septum, and find (i) suture between the vomer and ethmoid ; (2) junction between cartilage and ethmoid ; (3) the naso-palatinc groove on the vomer, containing a nerve and an artery of the same name. The nerve, a branch of Meckel's ganglion, one on each side, passes through the foramina of Scarpa, in the anterior palatine canal (Fig. 74), and anastomoses with the anterior palatine nerves, also branches of Meckel's ganglion. (Figs. 53 and 75.) The turbinated bones (Fig. 77) are three in number. They occupy the outer wall, as follows fractionally : The superior turbinal, the posterior third ; the middle turbinated, the posterior two-thirds ; the inferior turbinated extends the whole length of the wall. NA SA L OLFA CTOR Y FRONTAL SINUS NERVE NERVE OLFACTORY NERVE TO SUPERIOR TL'R- JilNA TE BONE SPHENOIDAL SINUS VIDIAN NERVE MECKEL'S GANGLION DESCENDING PALATINE ORIFICE OF EUSTACHIAN TUBE NASAL BRANCHES POSTERIOR PALATINE ANTERIOR PA LA TINE MIDDLE PALATINE FIG. 75. NERVES OF THE NASAL CAVITY. Tlie Etluno-turbinals (Fig. 77). This name is given to the superior and middle turbinals. They belong to the lateral mass of the ethmoid bone. The meatuses are three irregular cavities on the outer wall of the nasal fossae. Into them open the nasal duct and the frontal, ethmoidal, maxillary, and sphenoidal sinuses : Inferior, receives the nasal duct conveying the tears. Middle, receives the openings the antrum, frontal, and anterior ethmoidal cells. Superior, the opening of the sphenoidal and posterior ethmoidal cells. Describe the nasal mucous membrane. It is called pituitary membrane, from an erroneous idea entertained by the ancients that the nasal deflections had their origin in the pituitary body. It is also called the Schneiderian mucous membrane. In the regions of the turbinals and septum it is thick, vascular, and loosely attached to the bone ; in the bottom of the meatuses and in the intramural sinuses communicating with the nasal H4 PRACTICAL ANATOMY. fossae it is thin. It is continuous with the mucous membrane of all the cavities with the nasal fossae communicante. Name the arteries that supply the nasal fossa. 1. The anterior and posterior ethmoidal supply the roof, outer wall, and upper half of the septum. These are branches of the ophthalmic, and leave the orbital cavity by the anterior and posterior ethmoidal foramina. The companion veins have like name, and are tributary to the ophthalmic vein. Infection in this region, then, might extend along the ophthalmic vein to the cavernous sinus, since this vein has no valves. 2. The spheno-palatine supplies the lower half of the septum, the turbinals, the meatuses, the frontal sinuses, and the antra. The companion veins of these arteries are confluent to the pterygoid plexus on the inner side of the internal pterygoid muscle ; the veins take the same name as the arteries. The pterygoid Frontal sinusec MIDDLE TURBINAL BONE NASAL SEPTUM RIGHT ANTRUM INFERIOR TURBINAL BONE FIG. 76. TRANSVERSE SECTION PASSING THROUGH THE NASAL Foss^: AND ANTRA AT THE POSTERIOR EXTREMITY OF THE MIDDLE TURBINAL BONE. (Seen from the front.) plexus communicates with the cavernous sinus by the Vesalian vein. Infection from this region may reach the sinus, since the Vesalian has no valves. 3. The descending palatine and Vidian arteries, branches of the internal max- illary, supply the nasal fossae. What can you say of the nasal mucous membrane in relation to nose bleeding , and in what way may a violent hemorrhage from the nose abort cerebral apoplexy ? The venous blood in the mucous membrane of the nose communicates with the superior longitudinal sinus, in the falx cerebri, by an emissary vein which passes through the foramen caecum in front of the crista galli. The nasal mucous membrane is very vascular and quite loosely attached, a condition favoring easy rupture of its vessels. In cerebral congestion of the face the ocular and nasal mucous membranes become engorged, on account of their communication with the sinuses. On account of its lax attachment the vessels of the nasal mucous THE HEAD AND NECK. 115 membrane frequently give way, and hemorrhage results. This occurs more fre- quently in children than in adults. Describe the nerve-supply to the mucous membrane of the nose. 1. The olfactory nerves are distributed to the Schneiderian membrane of the upper third of the septum, and to the superior and middle turbinals. 2. The nasal nerve, a branch of the ophthalmic division of the fifth nerve, supplies the anterior half of the roof, outer wall, and inner wall of the nasal fossae with common sensation. 3. The upper branches of Meckel's ganglion and the Vidian nerve supply the posterior half of the roof, outer wall and inner wall, and the superior tur- binal. 4. The anterior palatine branch of Meckel's ganglion on its way down to the roof of the mouth supplies the middle and inferior turbinals. Frontal sinus Orifice of middle ethmoidal cells SUPERIOR TURBINAL BONE Orifice of the posterior ethmoidal cells Orifice of the sphenoidal sinus Sphenoidal sinus Orifloe of frontal sinus UPPER ORIFICE OF NASAL DUCT ORIFICE OF EUSTAOHIAN TUBE LOVvER ORIFICE OF NASAL DUCT MIDDLE TURBINAL BONE INFERIOR TURBINAL BONE ORIFICE OF THE ANTRUM ORIFICE OF INFUNDIBULUM FIG. 77. SECTION OF THE NOSE, SHOWING THE TURBINAL BONES AND MEATUSES, WITH THE OPENINGS IN DOTTED OUTLINE. 5. The naso-palatine branch of Meckel's ganglion supplies the lower and posterior part of the septum. The anterior superior dental nerves supply the inferior turbinated bone, hence a disease of this bone may cause pain in the ear or in any of the teeth. The Intramural Sinuses. This is a convenient term by which to distinguish the air-containing cells, in connection with some of the bones of the skull and face, from the dural sinuses in the dura mater, whose use is to contain and convey blood away from the brain. These sinuses are the ethmoid, the sphenoidal, the mastoid, the maxillary or antrum of Highmore, the frontal, mastoid antrum, and mastoid cells. As they all communicate directly or indirectly with the nasal fossae, we will consider them in this place. The mastoid cells communicate with the middle ear, and this with the pharynx by the Eustachian tube. The others communi- cate with the nasal fossae as indicated in figure 77. Formation. The intramural cells are formed by absorption of the middle n6 PRACTICAL ANATOMY. or diploic plate of bone. They are lined by mucous membrane. Infection is very liable to occur in these sinuses. The difference between the mucous mem- brane of the sinuses and that of the mouth is this : the latter is more vascular, more hardy, more resisting, both to infection and traumatic causes, on account of its location being such that exposes it to friction. Structure being the correlative of function, an increased blood-supply would logically account for the superior hardihood and less vulnerable character of the mucous membrane of the mouth, and all other regions where friction is a consideration inseparable from the environment. Take special notice that 1. The orifice of the Eustachian tube is on a direct line with the inferior meatus. 2. A fine straw or bristle can be passed through the infundibulum (Fig. 77) of the frontal sinus, into the middle meatus. 3. A straw can be passed through the nasal duct into the inferior meatus ; by turning the inferior turbinated bone up, you can easily see the orifice for the nasal duct. 4. The inferior meatus is located between the floor of the nasal fossae and the inferior turbinated bone, and receives the end of the nasal duct. (Fig. 77.) ANTRUM POSTERIOR PALATINE GROOVE PALATINE PROCESS NASAL PROCESS RIDGE FOR MIDDLE TURBINAL LACHRYMAL GROOVE RIDGE FOR INFERIOR TURBINAL NASAL SPINE CREST ANTERIOR PALATINE GROOVE FIG. 78. THE LEFT MANILLA. (Inner view.) 5. The middle meatus is situated between the inferior and middle turbi- nated bones. It receives the opening for the antrum, frontal sinus, and anterior ethmoidal cells. (Fig. 77.) 6. The superior meatus is located between the middle and superior turbi- nated bones, and receives the openings for the sphenoidal sinus and for the posterior ethmoidal cells. (Fig. 77.) The antrum of Highmore (maxillary sinus] (Figs. 68 and 76) occupies the interior of the body of the superior maxilla. Its medical and surgical importance entitle it to the following analytical consideration : 1. It has a roof, a thin plate of bone that forms the floor of the orbit. In this roof is the infraorbital nerve and vessels. (Fig. 51.) 2. A floor formed by the alveolar process of the upper jaw. The fangs of the teeth may produce irregularities of this floor. (Fig. 76.) The surgeon may gain access to the cavity by extracting a first or second molar tooth. 3. Inner ivall. The importance of this wall is the presence of the normal opening, by which the antrum communicates with the nasal fossae. (Fig. 77.) The surgeon may gain access to the antrum for drainage by this wall. 4. Anterior wall. On the inner surface of this wall are the anterior superior THE HEAD AND NECK. 117 dental canals, containing vessels and nerves for the teeth. (Fig. 51.) On the outer surface of this wall is the infraorbital plexus of nerves, formed by the infraorbital branches of the fifth and seventh nerves. Entrance to the antrum for purpose of drainage is gained by going through this wall too. 5. Posterior ivall. On this you will find the posterior dental canals for nerves and vessels to the posterior teeth of the superior maxilla. (Fig. 5 I.) The apex of the antrum corresponds to the prominence of the cheek. W hat can you say of the size of the antrum of Highmore, or maxillary sinus ? It will contain about one ounce of fluid. It is variable in size in different persons. It is longer in the male than in the female. A large bone may have a very small antrum, and vice versa. IV hat can you say of the floor of the ai/tniui / The floor is the strongest wall. It is uneven on account of the roots of the teeth, the first and second molars being usually those producing the uneven- ness. These tooth-roots may even penetrate the floor of the antrum, and be the exciting cause of disease of the antral mucous membrane. The antrum may be divided into several compartments, or pockets, as they are called, by bony par- titions of variable thickness and height, a circumstance which must always enter INFRAORBITAL FORAMEN NASAL NOTCH CANINE FOSSA NASAL SPINE INCISIVE FOSSA CANINE EMINENCE BORDER OF SPHENO-MAX1LLARY FISSURE FOR SPHENOID ZYGOMATIC SURFACE MALAR PROCESS POSTERIOR DENTAL CANALS TUBEROSITY FIG. 79. THE l.v.vv MAXILLA. (Outer view.) as a prognostic factor in operations to establish drainage on the antrum. The surgeon should ask himself after each operation, " Have I drained the antrum or only a pocket of the antrum ? " A merchant had a wine-cellar flooded with water. He employed a company to remove the water. A hose was thrust through a dark window and the pump started. To the dismay of the merchant, the experts had thrust the hose into a hogshead of wine, and drained the pocket, instead of the cellar. What cany 'ou say of the nerve -supply of the antrum ? The nerve-supply of the mucous membrane of the antrum comes from the anterior and posterior superior dental branches of the fifth nerve. You will remember this : The dental nerves supply the teeth ; the skin of the lips and cheeks covering these teeth outside ; the gums surrounding these teeth, through small branches called the nervuli gingivales ; and, lastly, the mucous membrane of the antrum. Describe the blood-supply of the antrnin f The internal maxillary artery gives off branches not only to the teeth (dental branches), but also branches to the gums (gingival branches), and antral branches to the mucous membrane of the antrum. These antral branches are accom- panied by sympathetic nerves. u8 PRACTICAL ANATOM\. To what is the nasal nerve distributed? To the septum, to the outer part of the nose, and to the two lower turbinals. This is a sensory nerve, a branch of the ophthalmic division of the fifth. It is found in the cranial, orbital, and nasal cavities. It traverses the anterior eth- moidal foramen and the nasal slit. Where is the olfactory nerve distributed ? To the roof of the fossa ; to the superior and middle turbinals ; to the upper half of the septum nasi. (Fig. 75.) Where is the spheno-palatine or Meckel 's ganglion ? In the spheno-palatine fossa, under the second division of the fifth nerve. It is the source from which the nose and mouth and palate derive their nerve- supply in great part. (Fig. 75.) Tlie sensory root of Meckel' s comes from the second division of the fifth, called the spheno-palatine nerves. (Fig. 53.) The motor root comes from the seventh or facial nerve, through the large FRONTAL SINUS NASAL PROCESS OF MAXILLA LACHRYMAL LACHRYMAL CANAL ORIFICE OF ANTRUM INFERIOR TURBINAL PALATE BONE ANTERIOR NASAL SPINE ANTERIOR ETHMOID CANAL POSTERIOR ETHMOID CANAL OPTIC FORAMEN OS PLANUM OF ETHMOID SPHENO-PALATINE FORAMEN VIDIAN CANAL, LEADING INTO THE SPHENO-MAXILLARY FOSSA SPHENOID EXTERNAL PTERY60ID PLATE PALATE BONE FIG. 80. A SECTION OF THE SKULL, SHOWING THE INNER WALL OF THE ORBIT, THE BASE OF THE ANTRUM, AND THE SPHENO-MAXILLARY FOSSA. superficial petrosal. This you can see in a groove under the dura, on the anterior surface of the petrous portion of the temporal bone. The nerve passes behind the Gasserian ganglion, down through the sphenotic foramen. It joins here, at the base of the skull, the large, deep petrosal branch of the carotid plexus. The two now pass through the Vidian canal. The result of the union of the large superficial petrosal of the seventh nerve and the large, deep petrosal of the carotid plexus is the Vidian nerve. (Fig. 53.) The last is the sympathetic root. Name the brandies given off by Meckel' s ganglion. (Fig. 53.) (i) Branches to the orbital periosteum; (2) branches to the mucous mem- brane of the nose; (3) anterior palatine to the roof of the mouth (Fig. 55) ; (4) naso-palatine in groove on nasal septum ; (5) branches to the upper pharynx behind luistachian tube. I introduce here, by consent of the author, some conclusions on the opening of the infundibulum in relation to the opening for the antrum of Highmore. I have given no special attention to the subject in the dissecting-room ; still, inci- THE HEAD AND NECK. 119 dentally, I have verified in seven cases the views of the author of the follow- ing : CONTINUED STUDY OF THE RELATIONS OF THE FRONTAL SINUS TO THE ANTRUM. BY THOMAS FILLEBROWN, M.D., D.D.S., BOSTON, MASS. PROFESSOR OF OPERATIVE DENTISTRY AND ORAL SURGERY, DENTAL SCHOOL OF HARVARD UNIVERSITY. (Read before the American Dental Association, August j, 1897, and reprinted from the '''Dental Cosmos" for December, 1897.) " Last year I made a report of some observations I had made on the formation of the infundibulum, showing that in many cases it continued directly to, and terminated in the foramen of, the antrum, and that a fold of mucous membrane mentioned by Merke, in 1834, extended above the foramen, forming a pocket, from the bottom of which the opening into the antrum is situated, thus directing any discharge coming down the infundibulum into the antrum, so that, under ordi- nary circumstances, no abnormal discharge from the frontal sinus would escape into the nasal passage until the antrum was filled so as to cause a backward overflow. " I mentioned the fact that Tilleaux, about 1840, noticed that of fluid injected into the frontal sinus, a great part flowed into the antrum, and that Dr. Cryer, in the same year, mentioned the same circumstance. He also showed that a probe could be passed from the antrum into the frontal sinus. I also noticed that Byran had mentioned the fact of occasional communications between the cavities, but considered them anomalies, and that Professor Harrison Allen had discussed the proliferation of empyema of the frontal sinus into the antrum. These obser- vations were of isolated cases, and were not proved or considered indicative of the normal anatomy of the parts. " I reported that the examination of eight different subjects showed that the infundibulum continued as a deep groove, or tube, open on one side down to the foramen of the antrum, and terminated in it, in every one of the eight cases, and that the pocket described was present in seven of the eight. This seemed to imply that the continuation of the infundibulum to the antral foramen and the presence of the pocket membrane was the normal formation. During the past winter I had opportunity to examine fifteen heads in the Harvard dissecting- room, and found the infundibulum continuing to the foramen of the antrum in every case. The membranous fold was present in every case, except on the left side of one subject. In this case the process was broad and flattened toward the meatus, and, though the mucous fold was absent, the widened process served the same purpose, as it formed a cup-shaped cavity quite as capacious as the pocket on the other side. " In another case the mucous fold was thickened and had considerable mus- cular tissue intermingled in its substance. " On the right side of this subject the infundibulum was very large, and in place of the ordinary foramen there were two openings, both quite large, fully one-fourth of an inch in diameter. " In another case the pockets were large, irregular in form, and deep, the mucous fold completely covering the infundibulum from the foramen of the frontal sinus to the antrum. " In one subject the mucous fold was considerably calcified. This condition had obtained to a degree throughout the whole system. This subject was advanced in years. This makes a total of twenty-three cases ; a number, I think, sufficient to establish the fact of the normality of the anatomy of the parts. " The very few variations only prove the rule. I hoped to secure the co-opera- i2o rRACTICAL AX ATOMY. tion of others in making further examinations during the winter, but the reprints of my paper were too long delayed, and the dissecting season was passed before I could communicate with anatomists and make the necessary arrangements and have the benefit of the results of the examinations of other subjects." THE COVERINGS OF THE BRAIN. Those structures intervening between the brain and the outside are brain pro- tectives,and may be called coverings. In number they are three ; in a collective sense, outer, middle, inner. The outer is called the scalp ; the middle, the cal- varium ; the inner, the meninges. As above intimated, each of these three cov- erings is a collective noun, and must be reduced, analytically, to its simplest terms of individual structures. The scalp consists of the following layers : 1. The skin, covered by a thick growth of hair in primitive man. 2. The superficial fascia, the distribution area where you are to find all the arteries, veins, nerves, and dermal muscles of the scalp. 3. The occipito-frontalis muscle, consisting of an anterior and a posterior belly, connected by a broad aponeurosis that takes the name of the muscle. 4. A subaponeurotic layer of connective tissue, which you can account for by consulting a paragraph in the introductory chapter on the non-apposition of anatomical structures. There are, then, four layers. The scalp moves .freely. The fibrous covering of the bone is periosteum, and its subperiosteal connective tissue does not differ from like tissue found underlying periosteum everywhere. These two structures do not form integral parts of the scalp because they do not move. Dissection. Remove the skin having shaved the head by making cross- incisions on the mid-top of the head, thus +. In the superficial fascia of the scalp you are to find the following structures : 1. The supraorbital nerve and vessels. (Figs. 16 and 18.) 2. The temporal branches of the seventh nerve. (Fig. 16.) 3. The auriculo-temporal branch of the fifth nerve. (Fig. 16.) 4. The temporal arteries superficial and veins. (Fig. 18.) 5. The great occipital nerve second cervical, posterior division. (Fig. 22.) 6. The small occipital nerve cervical plexus. (Fig. 22.) 7. The great auricular nerve cervical plexus. (Fig. 22.) 8. The posterior auricular artery branch of the external carotid. 9. The posterior auricular nerve branch of seventh cranial. (Fig. 16.) The above structures you have already found in your dissection of the face and neck. 10. The dermal muscles are as follows (Fig. 14) : 1. Musculus attrahens aurem draws the ear forward. 2. Musculus attollens aurem draws the ear upward. 3. Musculus retrahens aurem draws the ear backward. They have origin and insertion as indicated in the figure. They are insig- nificant, and can only be demonstrated in some cases. The function of these muscles is seen in some of the domestic animals the dog, horse, and mule. The occipito-frontalis (Fig. 14) has a posterior attachment to the outer two- thirds of the superior curved line of the occipital bone and to the mastoid process of the temporal bone. This muscular belly terminates anteriorly in a broad epi- THE HEAD AND NECK. 121 cranial aponeurosis. Follow this forward to the anterior belly. The anterior belly was described with the face. The calvarium (Fig. 8 1 ) or second covering of the brain has three layers called tables. They are named and distinguished as follows : (i) an outer, tough and resisting ; (2) a middle table which is porous or spongy, called diploe. This is very porous and contains many diploic veins that bleed rather freely during trephin- ing. The characteristic of this table of some of the bones of the cranium is to become absorbed. The intramural sinuses (see p. 1 13), as the frontal, ethmoid, sphenoid, mastoid, may be considered as owing their formation to this process of absorption. (3) The inner or vitreous table is hard and brittle. The inner surface is grooved for the accommodation of the meningeal arteries (Fig. 81), the nutrient arteries to the dura mater and calvarium. The meninges form the third or innermost of the three grand protectives of the brain. This covering consists of a dura mater, an arachnoid, and a pia GONION OB EXTERNAL OCCIPITAL PRO- TUBERANCE BASION FIG. 81. THE SKULL IN SAGITTAL SECTION. mater. The arrangement they bear to each other makes two physiological lymph spaces: (i) a subdural ; (2) a subarachnoid. These terms are self- explanatory, and conform to the rule of subs in the introduction. The dura mater is adherent to the bony walls of the calvarium and base of the skull. Its attachments are firmer in those localities where (i) great numbers of nerves are leaving ; (2) where there are numerous foramina ; (3) where there are many sutures. The base of the skull possesses these three characters, hence here the dura is most intimately adhered. The dura mater has four double processes, called : (i) Falx cerebri ; (2) falx cerebelli ; (3) tentorium cerebelli ; (4) diaphragma sellse. Each process possesses (i) a free margin; (2) an attached margin; (3) sinuses for the reception of venous blood from the brain. The diaphragma sellae is an inconsiderable dural process attached to the margin of the sella turcica, or pituitary fossa, qn the superior surface of the body 9 122 PRACTICAL ANATOMY. of the sphenoid bone. In its attached margin is the circular sinus. Under this process of dura is the pituitary body. This body is connected to the tuber cinerium on the floor of the third ventricle of the brain by the infundibulum, which latter passes through an aperture in the diaphragma sellae. The falx cerebri (Fig. 82) is between the cerebral hemispheres. It is attached in front to the crista galli of the ethmoid bone ; behind, to the tcntorhnn cerebelli ; above, to the inner surface of the caharium, in the mid-line, and extends from the tentorium to the crista galli. It contains in its attached margin the superior longitudinal sinus; in its free margin its inferior longitudinal sinus. The superior sinus contains the chords Willisii, mechanical devices for strengthening and holding its walls together. Blood in this sinus flows from before backward ; the sinus is fed by veins which open into it from behind forward. FOURTH NERVE Fall oerebri THIRD NERVE SECOND NER VE Tentorium cerebeUi Lateral sinus Superior petrusal sinus Falx oerebelli SEVENTH AND EIGHTH NERVES NINTH, TENTH, AND ELEVENTH NER VES TWELFTH NER VE SECOND CERVICAL NERVE Ligamentum denticulatum FIFTH NER VE FIRST CERVICAL NER \ 'E Inferior petrosal sinus FIG. 82. THE CRANIUM OPENED TO SHOW THE FALX CEREKRI, THE TENTORIUM CEREBELLI, AI THE PLACES WHERE THE CRANIAL NERVES PIERCE THE DURA MATER. (Sappey.) The falx cerebelli is the smallest of the three large dural processes of th( dura. It is between the cerebellar hemispheres. Its attached margin corresponds to the internal occipital crest of the occipital bone. It contains the occipital sinus. The tentorium cerebelli is midway, both in location and size, between the two preceding processes. It is between the occipital lobes of the cerebrum and the cerebellum. It protects the latter from the weight of the former. It is attached to the horizontal part of the occipital crucial ridges posteriorly ; anteriorly and laterally, to the superior border of the petrous portion of the temporal bone and to the clinoid processes of the sphenoid bone. In the occipital attachment are found the lateral sinuses ; in the temporal, the superior petrosal sinuses, The dura mater has sinuses located as follows (Figs. 82 and 83) : 1. Superior longitudinal, in the attached margin of the falx cerebri. 2. Inferior longitudinal, in the free margin of the falx cerebri. 3. Lateral, in the occipital attached margin of the tentorium cerebelli. THE HEAD AND NECK. 123 4. Superior petrosal, in the petrosal margin of the tentorium cerebelli. 5. Inferior petrosal, at the inner posterior border of the petrosa. 6. Occipital, in the attached margin of the falx cerebelli. 7. Cavernous, external to body of the sphenoid bone. 8. Circular, in diaphragma sellae, around the pituitary body. 9. Sigmoid, on the inner part of the mastoid process. 10. Transverse, connecting the inferior petrosal ; also called basilar. 1 1. Straight, at junction of falx cerebri and tentorium cerebelli. The arteries of the dura mater are the great, small, anterior, and posterior meningeal ; the anterior and posterior ethmoidal ; and branches of the occipital and ascending pharyngeal. The nerves to the dura mater are the sympathetic, ophthalmic, hypoglossal, the pathetic, and the Gasserian ganglion. As you have seen in your dissection, the dural sinuses are between the two layers of the dura mater. They are for the reception and transmission of venous Falx cerebri Choroid plexus Veins of Galen Tentorium cerebelli Lateral sinus CORPUS DENTA TUM CA UDA TE NUCLEUS LATERAL VENTRICLE Superior petrosal sinus MASTOID ANTRUM Lateral sinus MASTOID PROCESS FIG. 83. CORONAL SECTION OF THE HEAD PASSING THROUGH THE MASTOID PROCESS. (From a mounted specimen in the Anatomical Department of Trinity College, Dublin.) blood from the brain. The sinuses are lined by endothelial cells, continuous with the lining of the veins. The arachnoid membrane you will know by the glistening appearance it gives the brain. Externally it is in relation with the subdural space ; internally with the subarachnoid space. Where is the subdural space located and what does it contain / It is located between the dura mater and the arachnoid membrane, and con- tains a small amount of fluid. Call this fluid subdural. The subaracJmoid space is wJicrc located and contains what / It is located between the arachnoid membrane and the pia mater. It contains the greater part of the cerebro-spinal fluid. Call this fluid subarachnoid. Docs the subdural fluid communicate with the subarachnoid fluid ? No ; the two are separated from each other by the arachnoid membrane. 124 PR A CTICAL ANA TOM* . h tlic pin j f later a/so intact, so as not to permit communication between the sub- arachnoid fluid and the ventricular fluid in the ventricular cavities of the brain ? No ; the pia mater has many slits, by which it permits the fluid in the sub- arachnoid space to communicate with other lymph spaces. The main ones are in the pia mater covering the fourth ventricle. They are three in number : Key, Retzius, Magendie. (Fig. 84.) The arachnoid is covered externally with endothelial cells. It is joined to the pia by fibrous trabeculae, called the subarachnoid tissue. At the base of the brain it is separated from the pia mater by the anterior and posterior subarach- noid spaces. The anterior is between the temporo-sphenoidal lobes of the cerebrum and in front of the pons Varolii ; the posterior subarachnoid space is between the medulla and cerebellum. These two spaces contain the greater HKLU'ATK aUBARACHNOID TIVSfK <'O.\.\Kt"ri.\<; THE Ml\< IIMill, TO THK /'/.I MATKII OVKH Til/:' Cll.\ VKXl TY OP THK HKAIX BRAIN POSTER f (tit SI' HA KM' II- HO ID SPACE /'O/M.I/A'.V III-' KKY IX THK /'/.I .VATKIt n>K.\MK\ 01-' MM1KMHK f\ THK I>IA MATKK /'ill. I.I/A'.V <>r KKT/.irs !\ THK !/.( MATER FIG. 84. SCHEMATIC. To show the location of the foramina of Key and Retzius in the pia mater, whereby the subarachnoid fluid in the subarachnoid space communicates with the fluid in the fourth ventricle. part of the subarachnoid fluid. The posterior space communicates with the fourth ventricle of the brain through the pia mater by the foramina of Key and Retzius. (Fig. 84.) Where is the cerebro-spinal fluid found and ivliat are its uses t The subarachnoid or cerebro-spinal fluid is found in the subarachnoid spaces of the brain and cord and in the ventricular cavities of the brain. Its use is to mechanically protect the nerve centres from shock, and to fill up space, as fat does in some other parts of the body. Its amount is estimated at less than two ounces. The cerebro-spinal fluid of the brain and cord communicate. Explain t/ie special features of the subarachnoid space. As shown in figure 84, the greater part of the space between the arachnoid membrane and the pia mater is occupied by delicate connective tissue. It is im- THE HEAD AND NECK. 125 possible to separate the two membranes whenever this is the case. At the base of the brain you will see some well-defined spaces on removing the brain. The Pacchionian glands will be seen as little stubby hairs or even delicate enlargements on the arachnoid membrane, in the neighborhood of the superior longitudinal sinus. They are enlarged villi of this membrane. They often per- forate the dura mater. Occasionally they will be found to perforate the bones of the skull. Their use is not positively known ; but they seem to transmit subarachnoid fluid into the superior longitudinal sinus. Of ivliat is the pia mater composed ? It is composed of vessels and connective tissue. Where is the pia mater found in practical dissection on the cadaver ? The pia mater is found : (i) Covering the surface of the brain ; (2) in the interior of the brain, in the third and lateral ventricles, as velum interpositum and choroid plexus ; (3) forming the tela choroidea inferior along the roof of the fourth ventricle. This latter is perforated by three foramina, by which fluid in the ventricles communicates with fluid in the subarachnoid space. (Fig. 84.) SUBARA CHNOID SPA CE Superior longitudinal sinus PA CCHIONTA N BODY CORPUS CALLOSUM FIG. 85. CORONAL SECTION THROUGH THE GREAT LONGITUDINAL FISSURE, SHOWING THE MENINGES. (Key and Retzius.) Distinguish between the dura mater surrounding the brain and the dura sur- rounding the spinal cord as follows : 1. Attachment to bone, firmly and laxly periosteal function. 2. Dural processes, for supportive purposes. 3. Dural sinuses, for venous blood. 4. Pacchionian bodies ; Pacchionian villi. These four conditions are found in the cranial dura mater ; the dura of the cord has neither attachments, processes, sinuses, nor Pacchionian bodies. To remove a brain take the following steps : If the case is a post-mortem, then it is necessary to conduct your work so as to leave the subject in a present- able form. In this case make (i) an incision from ear to ear through the scalp, turn the front flap down over the face, the back one down onto the neck ; (2) cut through the origin of the temporal muscle, along the complete temporal ridge. Turn this muscle and its heavy fascia down over the zygoma. To Mark the Calvarium. Make a line from one-half of an inch above the supraorbital arch on each side, around the head, passing through the external occipital protuberance. Caution : Avoid getting too low in front, lest your incision pass under the roof of the orbit. If you fail to bring your incision to the level 126 PRACTICAL ANATOMY. of the external occipital protuberance you will have trouble in removing the cere- bellum. To Cut the Calvarium. Saw in the line as indicated in the preceding paragraph. Avoid cutting too deeply in the temporal region. After you have completed the incision with the saw, take a chisel and hammer and test your work. If any places remain uncut, you can easily finish loosening the calvarium with the chisel. The calvarium must be made loose without cutting through the dura mater. Grasp the cut edge of bone above the orbits, and, while an assistant presses down on the chin, pull the calvarium backward ; as it comes off you will hear a noise, produced by the separation of the dura from the bone. On a previous page you have learned that the dura has attachments to the interior of the cranium. Now make the following observations : 1. Note on the inner surface of the calvarium the meningeal grooves for the meningeal arteries. These arteries are between the dura and bone. They furnish blood to both dura and bone. They have nothing to do with the blood-supply to the brain proper. 2. The Pacchionian bodies and villi (Fig. 82) will be seen on the outer sur- face of the dura mater, in some cases where they have perforated this structure. They produce, by pressure atrophy, the Pacchionian depressions in the inner table of the calvarium. They are a villous product of the arachnoid. Their function is not perfectly understood. They are found in great abundance in the region of the superior longitudinal sinus, and even in the sinus itself. 3. You will note the great or middle meningeal artery. It consists of several branches, which all spring from one parent stem in the middle fossa of the skull. It lies in the connective tissue that held the dura to the bone. 4. The superior longitudinal sinus (Figs. 82 and 83) lies in the mid-line. Cut this open from end to end. Take note of the large amount of clotted blood it contains in its posterior half. Make note also of the chordae Willisii in the bottom of the sinus. Clear out the clotted blood, and these cords of Willis will come into view. 5. The Cerebral Veins. Cut through the dura, with scissors, one inch ex- ternal to the sinus just opened, from before backward, parallel with the sinus. Next make a lateral incision from the first incision to the ear. Do this on both sides. Turn the flaps outward. Turn the. dura up over the median line, and see the veins opening into the sinus from behind forward. Origin of the Cerebral Veins. These veins take blood from the part of the brain supplied by the cortical system given off from the circle of Willis. They discharge the blood into the several dural sinuses. 6. The subdural space is exposed now. It is between the dura and arach- noid. It contains a small amount of fluid for lubrication fluid derived from a source explained in a previous paragraph. This space contains (i) the Pac- chionian bodies ; (2) the veins to the sinuses ; (3) the cranial nerves prior to their emergence. 7. The falx cerebri (Fig. 82) you will see occupying the great longitudinal tissure between the cerebral hemispheres. Cut its attachment to the crista galli in front, and as you pull it gently backward, cut the remaining veins opening into the sinus. In the free margin of the falx cerebri is the inferior longitudinal sinus. 8. The arachnoid membrane is the smooth, glistening, transparent structure that you now see covering the brain. It is transparent, for you see the vessels of the pia mater through it. It is smooth on its outer surface, for it is lubricated by the subdural lymph. It is so very delicate you would scarcely suspect its presence. Under it is the subarachnoid space, also containing fluid. THE HEAD AND NECK. 127 9. The Pia Mater. As you have just observed, you can not remove the arachnoid from the pia ; still, you can see perfectly the vessels of the pia mater through the arachnoid. The presence of the subarachnoid tissue prevents separation of these two structures. (Fig. 84.) The pia mater is composed, as you can see on your dissection, of (i) arteries from the circle of Willis, taking blood to the brain ; (2) veins attending these arteries, and finally opening into the dural sinuses ; (3) connective tissue holding these arteries and veins, as the warp of a carpet holds the woof. Remember, the individuality of the pia mater depends not on arteries alone, not on veins alone, not on connective tissue alone ; but on all three woven together, the connective tissue being the warp, the vessels the woof. Meningeal branch, of anterior ethmoidal artery Jfeningfal branch of pos- terior ethmoidal artery Middle meningeal artery OPHTHALMIC DIVISION OF FIFTH NERVE THIRD NER YE Cavernous sinus FOl'RTH NERVE AUDITORY AND FACIAL NERVES Superior petrosal sinus Inferior petrosal sin-as Petro-sijiiamous sinus SPINAL ACCES- SOR Y NER VE Sigmoid portion of lateral sinus Posterior menimjeal bran ch of vertebral artery Left marginal sinus Left lateral sinus Superior longitudinal sinus Circular sinus Carotid artery SIXTH NERVE Basilar artery Basilar plexus of veins Auditory artery Vertebral artery GLOSSO-PHARYNGEAL AND PNEUMOGASTRIO Anterior spinal artery [N. HYPOGLOSSAL NER VE SPIN A L A CCES- SOR Y NER VE Right marginal sinus cipilal sinus Right lateral sinus FIG. 86. THE VENOUS SINUSKS. (From a dissection by W. J. Walsham in St. Bartholomew's Hospital Museum.) Structures You See on the Base. Place the cadaver so the head will hang over the end of the table. This position will permit the brain to gravitate to a slight degree out of its bed. Gently shake the brain by rocking the head from side to side. Notice now the following structures : 1. The frontal lobe of the cerebrum in the anterior fossa. 2. The olfactory lobe, on the under surface of the frontal lobe. 3. The optic chiasm and optic nerves. 4. The internal carotid artery its cerebral stage. 5. The third cranial nerve motor oculi. 6. The tentorium cerebelli attached to the petrosa. Hints on Dissection of the Foregoing Structures. Gently retract the frontal lobes and you will see the optic nerves covered by their prolongation of 128 PRACTICAL ANATOMY. arachnoid. Remove this with one braimvard sweep of the forceps, and expose the optic chiasm. Behind this see the infundibulum, attached above to the brain and below to the pituitary body. See it passing through a hole in the dia- phragma sellae. The internal carotid artery will be seen to the outer side of the optic nerve. Do not call this large artery the ophthalmic. Cut the optics behind the chiasm. Cut the internal carotid artery close to the anterior clinoid process. You will now expose the third nerve by breaking the prolongation of arachnoid about it. The fourth cranial nerve lies under the free margin of the tentorium. You will see the tentorium attached to the superior border of the petrosa in front. Cut along this border on both sides. Now gently retract the brain. The fourth nerve will pass to the outer side of the posterior clinoid process and disappear under the dura into the cavernous sinus. The fifth nerve will now be seen crossing the superior border of the petrosa, near the apex. It also disappears under the dura through the trigeminal notch. The sixth nerve will be seen going through the dura one inch below the dorsum sellae. It passes beneath the dura to gain the cavernous sinus with the third and fourth nerves, and the ophthalmic branch of the fifth nerve. Find now the seventh or facial nerve, the eighth or auditory nerve, and the auditory artery passing through the internal auditory meatus on the posterior surface of the petrosa. Note the funnel of arachnoid that accompanies these structures to the foramen. The ninth, tenth, and eleventh nerves will now be seen leaving the cranial cavity through the jugular foramen. The twelfth nerve leaves as two twigs : after passing through the dura they unite as one nerve, and leave the skull by the anterior condyloid foramen. FORAMINA AT THE BASE OF THE SKULL AND THE STRUCTURES THEY TRANSMIT. Foramen Caecum Transmits an emissary vein. Nasal Slit Transmits the nasal branch of the ophthalmic nerve. Olfactory Foramina Twenty in number, transmit the olfactory nerves. Optic Foramina, ...... Transmit the optic nerves and the ophthalmic artery. Sphenoidal Fissure Transmits third, fourth, sixth, and first divisions of the fifth nerve, the ophthalmic vein, and sym- pathetic nerves. Foramen Rotundum, .... Transmits the second or superior maxillary divi- sion of the fifth nerve. Foramen Ovale, ...... Transmits the third division of fifth nerve and small meningeal artery. Foramen Spinosum, Transmits the great or middle meningeal artery. Foramen, Sphenotic Transmits internal carotid and the facial and carotid petrosals for Vidian nerve. Hiatus Fallopii Transmits petrosal branch of the Vidian nerve. Petrosal Foramen Transmits the smaller petrosal nerve. Carotid Canal Transmits internal carotid artery and sympathetic nerves. Internal Auditory Meatus, . . Transmits seventh and eighth nerves and auditory artery. Jugular Foramen Transmits jugular vein, ninth, tenth, and eleventh nerves. Anterior Condyloid Foramen, Transmits the hypo-glossal nerve the twelfth nerve. Foramen Magnum, Transmits (i) spinal cord and its meninges; (2) the vertebral arteries and their sympathetic nerves ; (3) the spinal accessory nerve the eleventh nerve. Note the eleventh nerve coming up through the foramen, passing for- ward, and leaving the cranium with the ninth and tenth nerves by the jugular foramen. THE HEAD AND NECK. 129 The Cavernous Sinus. The sinus is located between the apex of the petrous portion of the temporal bone and the sphenoidal fissure. Note that all the nerves you have just seen in the table passing through the sphenoidal fissure also pass through the cavernous sinus. The sinus contains the following structures : 1. The venous blood common to dural sinuses. 2. The cavernous stage of the internal carotid artery. KACH C/M.V/.IA XEIi VE Off ITU KXI'AI'R RE- I'EIVEX A PSU- TEVTIOS III-' MATEH FIG. 87. SCHEMATIC. To show the dura mater forming sheaths for the nerves as they leave the cranium. 3. The sympathetic plexus of nerves on the common carotid artery. 4. The ophthalmic division of the fifth cranial nerve. 5. The motor oculi, the third cranial, nerve. 6. The patheticus, the fourth cranial, nerve. 7. The abducens, the sixth cranial, nerve. Dissection. Remove the dura mater. Take hold of it in the region of the frontal bone, and pull it back. It will come off quite readily. Locate the CAVERNOUS SINUS INT.CAROTIO ARTERY - Fir,. 88. RELATION OF THE VARIOUS STRUCTURES PASSING THROUGH THE CAVERNOUS SINUS. internal carotid artery next to the sphenoid wall of the sinus. The small nerve on the artery is the sixth cranial. You will find the others on the outer wall, from above downward : third, fourth, and fifth. The Gasserian Ganglion. Remove in the same way the dura mater from the middle fossa as you did from the anterior, and you will expose the Gasserian ganglion in a depression on the anterior surface of the petrous portion of the temporal bone near the apex. The ganglion lies between two layers of subdural 1 3 o PRACTICAL ANATOMY. connective tissue, called Meckel's fascia. The relation of the ganglion to the internal carotid is of great importance in surgical operations on the ganglion. In figure 86 the artery will be seen behind the Gasserian ganglion, the third, fourth, sixth, and ophthalmic division of the fifth nerve, and Meckel's fascia. In other words, turn all these nerves aside and you will see the Gasserian ganglion between two layers of subdural connective tissue called Meckel's fascia. The space between these two layers of fascia is called Meckel's space. The space through which the fifth nerve passes, between the tentorium and the superior border of the petrosa, near the apex of the bone, is called the trigeminal notch. Turn the Gasserian ganglion out of its bed and cut through the lower layer of Meckel's fascia, and you will find the internal carotid. In operations for removal of the Gasserian ganglion, this relation of the ganglion to the artery must be borne in mind, since the only protection to the artery is a thin layer of Meckel's fascia. Find the superior maxillary division of the fifth nerve leaving by the foramen rotundum in the greater iving of the sphenoid. The inferior maxillary division you will find leaving by the foramen ovale in the greater wing of the sphenoid. Dissection and study of 1. The Gasserian ganglion, its branches and relations. 2. Meckel's fascia, anterior and posterior layers. 3. The middle, or great, and the other meningeal arteries. 4. The facial nerve, the seventh cranial in the petrosa. 5. The tympanic cavity, the tympanum or middle ear. 6. The petrosal stage of the internal carotid artery. 7. The cavernous stage of the internal carotid artery. Locate ike following anatomical structures : 1. The middle meningeal groove and its artery. 2. The superior border of the petrosa. 3. The inferior border of the petrosa. 4. The posterior surface of the petrosa. 5. The anterior surface of the petrosa. 6. The internal auditory meatus with the seventh and eighth nerves. 7. The hiatus Fallopii and great petrosal nerve. 8. The tegmen tympani or roof of the tympanum. 9. The foramen lacerum medium. Sphenotic fissure. 10. The foramen spinosum in the alar spine of sphenoid bone. 1 1. The sphenoidal fissure in the sphenoid bone. 12. The foramen ovale for third division of the fifth nerve. 13. The foramen rotundum for the second division of the fifth nerve. 14. The anterior, middle, and posterior clinoid processes. Describe the middle meningeal artery. It is a branch of the first stage of the internal maxillary artery. External to the cranium it lies behind the internal pterygoid muscle. It passes between the two roots of origin of the auriculo-temporal nerve. It enters the cranium by the foramen spinosum, in the great wing of the sphenoid bone, and ramifies between the dura mater and the bone, both of which it supplies with blood. Its two accompanying veins are tributary to the internal maxillary vein. The middle meningeal artery divides in anterior and posterior branches which supply the greater part of the bones of the cranium. (Fig. 81.) This vessel gives off the following minor branches : 1 . Small branches to the Gasserian ganglion and its adjacent dura mater. 2. A branch through the hiatus Fallopii to the seventh nerve and tympanum. 3. Temporal branches perforating the bone to the temporal fossa. 4. Orbital branches passing through the sphenoid fissure to the orbit. THE HEAD AND NECK. 131 From what other sources does tJie dura receive its blood-supply ? The anterior meningeal arteries are in the anterior fossa of the skull. They are derived from the ethmoidal branches of the ophthalmic artery, and from the cavernous stage of the internal carotid. The small meningeal is a branch of the first stage of the internal maxillary. It enters the cranium by the foramen ovale with the third division of the fifth nerve. The posterior meningeal arteries come from the vertebral, occipital, and ascending pharyngeal. Describe the cavernous stage of the internal carotid artery. It is in the cavernous sinus, but covered by the endothelial lining of the sinus. (Fig. 86.) From the inner end of its petrosal stage the artery ascends to the pos- terior clinoid process ; it then lies by the side of the body of the sphenoid, and then gently curves upward between the middle and anterior clinoid processes, and, lastly, curves backward and perforates the roof of the sinus. (Fig. 86.) On the outer side of the artery is the sixth nerve. It is surrounded by sympathetic nerves. In this stage the vessel gives off the following branches : 1. Branches to the walls of the cavernous sinus. 2. Branches to the Gasserian ganglion. 3. Anterior meningeal branches to the dura. 4. Branches to the pituitary body in the sella turcica. Describe the petrosal stage of the internal carotid artery. It has in this stage two parts : An ascending part, in front of the tympanum and internal ear ; a horizontal part, which you will see on turning the Gasserian ganglion backward. On the artery you will see numerous sympathetic nerves, the carotid sympathetic plexus, which are ascending branches of the superior cervical ganglion. The carotid, Vidian, and tympanic are its branches. WJiat are Mcckel' s fascia, Meckel 's space, Meeker s cave, and the trigcminal notc/i in the literature of the trigeminal nerve ? Meckel's fascia is the subdural connective tissue on and under the Gasserian ganglion. Meckel's space is between the two layers of dura, external to the cavernous sinus. Meckel's cave is a depression on the anterior surface of the petrosa for the Gasserian ganglion. The trigeminal notch is an osteological term ; it is a depression in the upper border of the petrosa, near the apex, in which the fifth nerve rests before expansion into the Gasserian ganglion. This notch is converted into the trigeminal foramen by the tentorium cerebelli. Describe the Gasserian ganglion. This ganglion lies in Meckel's cave, on the anterior surface of the petrosa. It is simply an enlargement on the anterior or sensory root, as it is called, of the fifth cranial nerve. Its posterior relations are the foramen lacerum medium, the great petrosal nerve, and the horizontal part of the petrosal portion of the internal carotid artery. Anterior to it is the dura mater. The ganglion gives off or receives the following branches : 1 . Filaments from the carotid plexus of the sympathetic. 2. Nerves to the dura of the middle fossa and tentorium. 3. The ophthalmic nerve to the orbit and nose. 4. The superior maxillary nerve to the upper jaw. 5. The inferior maxillary nerve to the mandibular region. Wliat is the function of the ganglion and the branches given off therefrom / It confers the quality of common sensation on all parts to which it is dis- tributed. Behind the ganglion lies a nerve that supplies the muscles of mastica- tion. This is the so-called motor root of the fifth nerve. This nerve has nothing to do with the ganglion. It leaves the base of the skull through the foramen ovale with the inferior maxillary sensory part of the ganglion. (Fig. 53.) The tympanum or middle ear may be very satisfactorily dissected by the 132 PRACTICAL ANATOMY. student. Its small size is no argument against careful study of its medical and surgical importance, its contents, and its relations, since it is of easy access for dissection, and resolvable into the form of a geometrical cube for purposes of aiding the memory and facilitating a comprehension of the relative position of those anatomical structures that make the middle ear of such great importance. The student should not undertake a dissection of this part until he has a clear- cut idea of the position, relation, and importance of each wall of the cube. If he begins his dissection knowing that the drum of the ear forms the outer wall of the tympanum proper, that the Eustachian tube and mastoid antrum commu- nicate with the tympanum by the anterior and posterior walls respectively, then he will surely find these structures and think of them in relation to the walls of a cube. To say nothing of the part played by the tympanum in hearing, this region is of interest and importance for the following reasons : 1. The temporo-sphenoidal lobe of the brain lies on its roof. 2. The floor of the tympanum lies on the jugular fossa. 3. The drum of the ear and chorda tympani are on the external wall. 4. The mastoid antrum and cells are behind it. 5. The internal carotid artery is in front of it. 6. The facial nerve skirts two sides of it. 7. The internal ear is in close relation with it. 8. The drum of the ear may become ruptured. 9. The interossicular joints may become ankylosed. 10. Pus may form in the tympanum. Size and Subdivisions of the Tympanum. The tympanum is about one-half of an inch in height and one-sixth of an inch in width. It is prolonged forward as the Eustachian tube and backward as the mastoid antrum, so its length is difficult to determine : for practical purposes one-half of an inch is near enough. The subdivisions are the attic and tympanic cavity proper. The latter is quite narrow, and has the membrani tympani or drum as its outer wall ; the former is broader, contains most of the bones of hearing, and has a part of the temporal bone as its outer wall. Remember, the tympanum is not horizontal, but its anterior end slopes downward, forward, and inward to the Eustachian tube ; its posterior end slopes upward, backward, and outward to the mastoid antrum. Study of the tympanum in which this cavity is compared to a box. (Fig. 91.) 1. The roof of the tympanum is a thin plate of bone, the tegmen tympani, separating the tympanum from the middle fossa at the base of the skull. It is perforated by foramina that transmit the petrosal branches of the seventh nerve. 2. The floor separates the tympanum from the jugular fossa, in which fossa are the internal jugular vein, and the ninth, tenth, and eleventh cranial nerves. In this floor is an aperture, through which Jacobson's nerve, the tympanic branch of the glosso-pharyngeal, passes to form the tympanic plexus. 3. The outer wall of the tympanum is formed by the drum below and the squamosa above, these two structures corresponding to the tympanum proper, and the attic respectively. This outer wall is pierced by the following openings : (i) The ifcr clionlie posterius, by which the chorda tympani nerve, a branch of the seventh cranial nerve, enters the tympanum ; (2) the iter chordtc aiiterins, by which the chorda tympani leaves the tympanum ; (3) the (i/aseriau Jissitre, through which pass the tympatiic branch of the internal maxillary artery, the processus gracilis of the malleus, and the laxator tympani muscle. 4. The inner isall, you will remember, is called the fourth surface of the 'petrosa, in Morris' analysis of this part of the temporal bone. This inner wall contains: (i) A ridge of bone covering the seventh nerve in its passage through the tympanum, as heretofore explained ; (2) the fenestra ovalis, leading into the vestibule, and to which is attached the base of the stapes, through THE HEAD AND NECK. 133 the medium of a periosteal membrane ; (3) the promontory, formed by a turn of the cochlea, and covered by the tympanic plexus ; the promontory is below and in front of the fenestra ovalis ; (4) the fenestra rotunda, covered by the membrana secundaria, and communicating with the scala tympani of the cochlea ; (5) the pyramid, from whose summit emerges the tendon of the sta- pedius. A special branch of the seventh nerve pierces the pyramid for the supply of the stapedius muscle. 5. The posterior ivall commu\\\ca.tQS with the mastoid antrum. As indicated in a previous paragraph, the mastoid antrum is the backward continuation of the upper part of the tympanic cavity, which is called the attic. 6. The anterior wall of the tympanum presents but one thing for examination the canalis musculo-tubarius. This canal is divided into an upper and a lower compartment by a horizontal lamina of bone, called the processus cochleari- formis. The upper compartment lodges the tensor tympani muscle ; the lower FIG. 89. EAR AND TYMPANUM. I. Pinna, or auricle. 2. Concha. 3. External auditory canal. 4. Membrana tympani. 5. Incus. 6. Malleus. 7. Manubrium mallei. 8. Tensor tympani. 9. Tympanic cavity. 10. Eustachian tube. II. Superior semicircular canal. 12. Posterior semicircular canal. 13. External semi- circular canal. 14. Cochlea. 15. Internal auditory canal. 16. Facial nerve. 17. Large petrosal nerve. 18. Vestibular branch of auditory nerve. 19. Cochlear branch. is the osseous part of the Eustachian tube. These structures can be readily seen in dissection. A common broom straw or hairpin may be thrust through the lower part of the canalis musculo-tubarius as a guide. Before you attempt to dissect the seventh nerve in its tortuous canal through the petrous portion of the temporal bone, study well the following branches this nerve gives off between the internal auditory meatus and the stylo-mastoid fora- men. In the auditory canal a short communicating branch, rather large and fatty, extends from the seventh to the eighth nerve. This is called the portio inter duram et mollem. The bony canal occupied by the seventh nerve, from the time it leaves the eighth nerve until it emerges from the stylo-mastoid foramen, is called the aqneductus Fallopii, or the facial canal. In this canal the following branches are given off, as you may see by figure 90. I. From the geniculate ganglion, the great superficial petrosal nerve ; this passes through the cartilage in the foramen lacerum medium, and is joined by 134 PRACTICAL ANATOMY. some filaments from the carotid sympathetic plexus, called the great deep petro- sal nerve. The union of these two makes a compound nerve called the Vidian nerve. This Vidian, accompanied by vessels of like name, passes through the Vidian canal and joins the ganglion of Meckel, conferring on the same motion and sympathetic qualities. You will recall the fact of osteology that the Vidian canal is at a junctional area formed by the greater ala of the sphenoid bone, its lingula and pterygoid process. Meckel's ganglion derives its sensory root from the spheno-palatine branches of the superior maxillary division of the fifth cranial nerve. 2. From the geniculate ganglion, the small superficial pctrosal nerve. This nerve receives a communicating branch from the glosso-pharyngeal nerve and leaves the cranium by the canalis innominatus in the sphenoid bone, between the foramen ovale and foramen spinosum, and joins the otic ganglion on the inner surface of the third division of the fifth nerve, near the foramen ovale. 3. From the geniculate ganglion, the external pctrosal. This nerve joins the Supraorbifal 5*.* ,ir V-G: ::--; M; Q(Uiic Ganij: *' FIG. 90. SCHEME OF FACIAL NERVE COMMUNICATING WITH THE FIFTH CRANIAL NERVE. sympathetic plexus on the great or middle meningeal artery, near the foramen spinosum. 4. From the nerve-trunk, below the geniculate ganglion, the tympanic brancli to the stapedius the smallest muscle in the body. This nerve pierces the pyra- mid, on the inner surface of the tympanum. 5. A branch frcm the carotid sympathetic plexus joins the great superficial pctrosal just outside the cranium, to form the Vidian nerve. 6. From the main trunk of the nerve (8 in Fig. 90) a branch is given oft", just above the stylo-mastoid foramen, to communicate with the auricular branch of the vagus nerve. 7. From the main nerve-trunk, just above the stylo-mastoid foramen, the cJwrda tympaui nerve is given off". This nerve passes upward through a bony canal, the iter chordae posterius, to the tympanum. It passes forward under the mucous membrane of the drum of the ear internal to the manubrium of the malleus. The nerve leaves the tympanum by the iter chordae anterius, or canal of Huguier. It communicates with the otic ganglion, passes internal to the external pterygoid THE HEAD AND NECK. 135 muscle, and joins the gustatory nerve. It is distributed to the submaxillary and sublingual glands and to the dorsum of the tongue. Dissection of the Seventh Nerve in the Petrosa and of the Tympanum. Locate the following anatomical structures : 1. The superior border of the petrosa. 2. Anterior and posterior surfaces of the petrosa. 3. The trigeminal notch near apex of petrosa. 4. The cave of Meckel on anterior surface of petrosa. 5. The horizontal part of the carotid canal and its artery. 6. The great petrosal nerve in the hiatus Fallopii. 7. The small petrosal nerve in its small canal. 8. The middle meningeal artery and foramen spinosum. 9. The tegmen tympani or tympanic roof. 10. The internal auditory meatus on posterior surface of the petrosa. With a small chisel and mallet gently remove the tegmen in such a manner as not to destroy the delicate petrosal nerves on the anterior surface of the petrosa, and then you can look down into the tympanum, or middle ear, the roof now having been removed (tegmen). Now draw a line from the internal auditory meatus to where the great petrosal nerve is seen emerging. This line will locate the course of the seventh nerve in its canal to the tympanum. Now begin at the internal end of the line just drawn and chip off the bone until you have completely exposed the seventh nerve to the tympanum, where you will see the geniculate ganglion giving off petrosal nerves. The tympanum may be represented as a box with an inner and an outer wall, a roof and a floor, an anterior and a posterior end. The seventh nerve approaches the tympanum, at a point corresponding to the junction between the roof and inner wall, near the front end of the box. The seventh nerve having gained this point, now passes backward in the angle between the roof and inner wall to the corner of the box between the inner wall and posterior end of the box. The nerve here makes a gentle turn and passes down this cor- ner to the floor of the box, and subsequently emerges from the base of the skull through the stylo-mastoid foramen. You may see the geniculate ganglion of the nerve just where the nerve is making the bend to enter the tympanum. Now locate the nerves as described previously, and consult figure 90. BLOOD-SUPPLY TO THE BRAIN. Examine the base of the brain. You notice very distinctly the arachnoid membrane quite appreciably separate from the pia. In other words, here you see the subarachnoid space. Now remove carefully the arachnoid and dissect the circle of Willis. You will note the following : 1 . The vertebral arteries unite to form the basilar artery. 2. The basilar divides into the two posterior cerebral arteries. 3. The internal carotid artery gives off three large arteries (Fig. 91) : (i) The anterior cerebral, in the great longitudinal fissure ; (2) the middle cerebral, in the fissure of Sylvius on the central lobe ; (3) the posterior communicating, to the posterior cerebral. The arachnoid membrane, it will be observed, stretches across from frontal to temporo-sphenoidal lobe, so as almost to obscure the fissure of Sylvius. Cut this membrane with the scissors, gently part the lobes, and you will see the island of Reil, on which is the middle cerebral artery with its vein. The anterior communicating artery is very short, one-eighth of an inch being an average length in a number of cases. You will find it extending from one anterior cerebral artery to the other. i 3 6 PR A CTICAL ANA TO. M J . The ganglionic or terminal end arteries will be seen in very great numbers on lifting the middle, posterior, and anterior cerebral arteries. They are very minute. Look closely, and you will see them passing through minute perfora- tions to the interior of the brain through the perforated spaces. (Fig. 92.) The interpeduncular space has (i) boundaries; (2) contents. The con- tents form the floor of the third ventricle. The boundaries are important structures on the base of the brain which I wish you to study carefully. (Fig. 92.) The Boundaries of the Interpeduncular Space. (i) Antero-laterally, optic chiasm and optic tracts ; (2) postero-laterally , pons Varolii and crura cerebri. Contents of Interpeduncular Space. (i) The tuber cinereum ; (2) infundibulum, pituitary body ; (3) the corpora albicantia, part of the fornix ; (4) posterior Anterior cerebral artery Middle cerebral artery Internal carotid artery Poslero-median perforating Posterior cerebral artery Superior cerebellar artery Anterior inferior ccrebellar artery Vertebral artery Posterior inferior cerebellar artery A nterior com- municating artery Antero-lateral perforating A nttrior clioroid Posterior communicating artery Posterior choroid Basilar artery Cfnis cerebelli, cut Anterior spinal artery FIG. 91. THE ARTERIES OF THE BRAIN. (From a preparation in the Museum of St. Bartholomew's Hospital.) perforate space, for terminal end arteries ; (5) the third cranial nerve, mot oculi nerve. Notice in particular : 1. The optic tracts crossing the crura cerebri. 2. The third nerve, motor oculi, between the crura cerebri. 3. The terminal end arteries from the circle of Willis. (Fig. 91.) 4. The basilar artery on the body of the pons Varolii. (Fig. 91.) 5. The fourth nerve, coming out between the pons and crus cerebri. 6. The fifth nerve, coming from the side of the pons Varolii. 7. The sixth nerve, coming through between the pons and medulla. 8. The seventh and eighth nerves, between the olivary and restiform bodies. 9. The ninth, tenth, and eleventh nerves, between the olivary and restiform bodies. 10. The twelfth nerve, between the pyramid and olive. THE HEAD AND NECK. '37 Two systems of circulation are given off from the circle of Willis: (i) Tlic ganglionic ; (2) tlie cortical. You have just seen the ganglionic or end arteries entering the brain by the perforated spaces. The cortical arteries and their veins form the woof of the pia mater, the warp of which is connective tissue. i . From what source docs the brain receive its blood ? The brain is supplied with blood by the circle of Willis. OPTIC THALAMUS OPTIC TRACT TUBER CINEREUM POSTERIOR PER- FORATED SPACE CORPUS GENICU- LA TUM EXTKRNUM CORPUS GENICU- LA TUM INTERNUM PYRAMIDAL BODY OLIVARY BODY ARCIFORM FIBRES ISLAND OF REIL PITUITARY BODY CORPORA ALBICANTIA CRUS CEREBRI PONS VAROLII GREA T HORIZONTA L FISSURE FLOCCULUS FORAMEN CAECUM SPIN A L A CCESSOR Y NERVE FIRST CER VICAL NER VE ANTERO-LATERAL GROOVE OF SPINAL CORD ANTERIOR COLUMN OF SPINAL CORD FIG. 92. SURFACE ORIGIN OF THE CRANIAL NERVES. (After Allen Thomson. Quain.) 2. How is this circle formed ? It is formed by an anastomosis between branches of the internal carotid and vertebral arteries. 3 . How does the internal carotid reach the brain ? It comes through the carotid canal and sphenotic foramen, and gives off: (i) The anterior cerebral ; (2) the middle cerebral ; (3) the posterior communi- cating. 4. Hoiv docs the vertebral artery reach tJie brain ? It passes through the foramina in the transverse processes of the cervical vertebrae and the foramen magnum. It divides into the two posterior cerebral arteries. 5 . How is the blood returned from the brain / The blood from the ganglionic system is returned to the straight sinus by 138 PRACTICAL ANATOMY. the veins of Galen. (Fig. 82.) The blood from the cortical system is returned by various veins to the several dural sinuses. 6. What becomes of the blood in the sinuses / The sinuses converge to form the internal jugular vein. This vein is made up at the jugular foramen, and leaves it in company with the ninth, tenth, and eleventh cranial nerves. 7. Do the branches given off from the ganglia nic system communicate until one another or with branches of the cortical system ? No. 8. Where do the branches forming the ganglionic system take their origin, and hoiv are they named? They originate from the circle of Willis and from its primary branches for an inch beyond the circle. They are named : Antero-median, from the anterior communicating artery. Antero-lateral, from the middle cerebral artery. Postero-median, from the posterior cerebral artery. Postero-lateral, from the posterior cerebral artery. 9. What is the most important function of this system of circulation / To supply blood to the basal ganglia, the most important part of the brain. 10. Name the most important branch of the ganglionic system, and give its surgical importance. The lenticulo-striate artery. It is the largest, and most frequently the seat of embolism or hemorrhage. It passes through the internal capsule. 1 1 . Do all the branches of the ganglionic system supply basal ganglia / No ; the anterior and posterior choroid branches supply the choroid plexuses of the lateral ventricles and some minor adjacent parts. 1 2. Has any part of the ganglionic system anything to do with the formation of the pia mater ? As mentioned in a previous paragraph, the anterior and posterior choroid arteries are branches of the ganglionic system, but they do not supply basal ganglia ; they supply the choroid plexuses, in the lateral ventricles, and these plexuses, with the velum interpositum, are extensions from the general pia mater on the surface of the brain to equally superficial parts of the brain, apparently, but not really, on the interior of the brain. 13. Arc the terms pia mater and cortical system of circulation, for practical purposes, synonymous / Yes ; the pia mater consists of vessels, arteries and veins, and connective tissue ; the arteries, for the most part, originate beyond the confines of the gang- lionic system. The pia mater is applied to every part of the outer surface of the brain ; it reaches into the fissures and sulci. It forms the velum interpositum and the choroid plexuses. 1 4. How are the cerebral veins classified / They may be grouped as ganglionic, basilar, and cortical, (i) The central or ganglionic veins come together to form the veins of Galen, having gathered in their course the veins of the choroid plexuses and velum interpositum. The veins of Galen, from the two hemispheres, unite to form the common vein of Galen, a trunk about one-half of an inch in length ; this, as seen previously, opens into the straight sinus. (2) The basilar veins collect the blood from the under surface of the cerebrum, and feed the petrosal, cavernous, and lateral sinuses. (3) The cortical veins gather the blood from the outer and inner surfaces of the hemispheres and feed the superior and inferior longitudinal sinuses in the attached and free margins of the falx cerebri respectively. THE HEAD AND NECK. 139 Find the following fissures and their contents : 1. Tlie great longitudinal fissure contains : (i) The falx cerebri with its superior and inferior longitudinal sinuses ; (2) the corpus callosum, on which you may see the anastomosis between the anterior and posterior cerebral arteries. 2. The great transverse fissure, between the occipital cerebral lobes and the cerebellum. It contains the tentorium cerebelli. 3. The fissure of Sylvius, bounded below by the temporo-sphenoidal lobe; above by the frontal and parietal lobes. It contains : (i) The island of Reil, or central lobe of the cerebrum ; (2) the middle cerebral artery and vein and their numerous branches. 4. The fissure of Rolando is between the ascending convolutions of the frontal and parietal lobes. Its surgical importance is due to the fact of the location of the cortical motor areas about this fissure. 5. The occipito-parietal fissure is very imperfect. As its name implies, it is between the parietal and occipital lobes. Dissection of the brain does not belong to dissecting-room anatomy, hence the reader is referred to Morris for this very interesting and instructive part of anatomy. THE ORBIT AND ITS CONTENTS. For dissecting-room purposes, the following points seem of practical or rather demonstrable importance : i. Geometry of the Orbit. Roof, floor, outer wall, inner wall, base, apex, angles, and cavity. The roofis of importance, since it separates the cavity of the orbit from the frontal lobes of the brain. A missile may reach the brain in this way, since this roof is often very thin. The floor is of importance (i) because it forms a partition between the orbit and the antrum of Highmore, or maxillary sinus ; (2) because it is traversed by the infraorbital canal, in which are the infraorbital nerve and vessels. The inner wall is in close relation with the nasal fossae, and the ethmoid cells, the os planum of the ethmoid, and the lachrymal bones form a large part of the partition between these cavities. The outer wall is formed by the orbital plates of the sphenoid and malar bones, but is of no special importance. The apex of the orbit transmits the optic nerve and the ophthalmic branch of the internal carotid artery. The apex is occupied by the optic foramen, be- tween the two pedicles of the lesser ala of the sphenoid bone. The base of the orbit is of great importance on account (i) of its architectural construction, combining beauty, strength, and protection ; (2) of the large num- ber of anatomical structures in this region. Note about the base of the orbit : 1. The laclirymal gland (Fig. 104), under the external angular process of the frontal bone, in a fossa called the lachrymal fossa. This is called the orbital part of the gland or the superior lachrymal gland ; the part of the gland that protrudes below this is called the palpebral portion or the inferior lachrymal gland. 2. The S2ipraorbital foramen (it may be double) transmits the supraorbital nerve and vessels. (Figs. 98, 103.) The vessels are branches of the ophthalmic. 140 PRACTICAL ANATOMY. The nerve is a branch of the frontal part of the ophthalmic, itself a branch of the fifth cranial nerve. 3. The trochlea is found on the inner wall, near the base of the orbit. Around this trochlea plays the tendon of the superior oblique muscle of the eyeball. (Fig. 100.) Here, too, occurs the anastomosis between the supra- trochlear branch of the frontal and the infratrochlear branch of the nasal nerve. The nasal duct has its beginning in the internal inferior angle of the orbital base. (Fig. 104.) By this duct excessive tears reach the nasal fossae. PALPEBRAL FISSURE INNER CANTHUS OUTER CANTHUS TENDO OCULI DELAMINATES INTO SUPERIOR AND INFERIOR PALPEBRAL RAMI Tendo oouli or internal tarsal ligament INFERIOR TARSAL LIGAMENT FIG. 93. TENDO OCULI AND TARSAL CARTILAGES. The infraorbital nerve (Fig. 51), emerges from the orbit by the infraorbital foramen just below the base of the orbit. This sends off anterior superior branches to the teeth just prior to its emergence. The tendo oculi crosses the lachrymal sac in front (Fig. 94), giving off an aponeurosis to the same. Observe the caruncula lachrymalis between the t\vo diverging rami of the tendo oculi. The tendo oculi, or internal tarsal ligament, has its origin from the nasal process of the superior maxilla. (Fig. 10.) The superior and inferior tarsal 1 1 15J FIG. 94. RELATIONS OF THE EYE AND THE LACHRYMAL EXCRETORY APPARATUS. I, I. Canalicirii. 2, 2. Puncta lachrymalia. 3, 3. Inner extremity of tarsal cartilage. 4, 4. Free borders of lids. 5. Lachrymal sac. 6. Attachment to maxillary bone of superior tendon. 7. Bifur- cation of lachrymal sac. 8, 8. Two branches. ligaments, of periosteal derivation (Fig. 21), are attached to the margin of the base of the orbit both above and below. The external tarsal ligament is not divided. The Angles of the Orbit. 1 . The superior internal. This contains the anterior and posterior etJnnoidal foramina. The former transmits the anterior ethmoidal artery and nasal nerve ; the latter, the posterior ethmoidal artery. 2. The superior external angle. This contains in front the lachrymal fossa already described, and posteriorly the sphcnoichil fissure. This fissure transmits THE HEAD AND NECK. 141 the third, fourth, sixth, and the three divisions of the ophthalmic branch of the fifth nerve, the ophthalmic vein, and some minor structures. 3. The inferior external angle. In this is the spheno-maxillary fissure. This fissure transmits the superior maxillary nerve and its orbital branches, the ascend- ing branches from Meckel's ganglion, the infraorbital branch of the internal max- illary artery and its vein. 4. The inferior internal angle contains the beginning of the osseous part of the lachrymal apparatus that conveys tears to the nasal fossae. This apparatus will be considered under the head of orbital contents. (Fig. 104.) The periosteum of the orbit (Fig. 95) lines the walls of the cavity, delaminates at the orbital margin of the base, one layer uniting with the peri- osteum externally, the other layer forming the tarsal ligaments and tarsal cartilages above and below. The orbital fascia is to the contents of the orbit, other things equal, what the deep fascia of the thigh is to the structures of the thigh. Keep this in mind, for here, as in the thigh, you will find sheaths, capsules, and septa derived from this fascia. In your dissection you will find the following structures 1. The optic nerve the special nerve of the sense of sight. (Fig. 100.) 2. The motor oculi nerve, or third nerve. (Fig. 98.) OPTIC FORAMEN DELAMINATION OF THE ORBITAL PERIOSTEUM arsal ligament Tarsal cartilage PALPEBRAL FISSURE ORBITAL PERIOSTEUM OHBITAL PERIOSTEUM FIG. 95. SCHEMATIC REPRESENTATION TO Snow RELATION OF PERIOSTEUM TO TARSAL CARTI- LAGES AND TARSAL LIGAMENTS. 3. The patheticus, or fourth nerve. (Fig. 98.) 4. The abducens, or sixth nerve. (Fig. 98.) 5. Ophthalmic branch of the fifth nerve. (Fig. 98.) 6. The lachrymal gland and its capsule. (Fig. 103.) 7. The ophthalmic artery and its branches. (Fig. 103.) 8. The ophthalmic vein and its branches. (Fig. 103.) 9. The ciliary ganglion and its branches. (Fig. 98.) 10. The orbital connective tissue and fat. 11. The levator palpebrae muscle. (Fig. 100.) 12. The superior rectus muscle. (Fig. 100.) 13. The external rectus muscle. (Fig. 99.) 14. The inferior rectus muscle. (Fig. 99.) 15. The internal rectus muscle. (Fig. 99.) 1 6. The superior oblique muscle. (Fig. 100.) 17. The inferior oblique muscle. (Fig. 100.) 1 8. The capsule of Tenon. 19. The eyeball with sclerotica and iris. (Fig. 99.) Dissection of the Orbital Contents Steps : I. Remove the orbital plate and supraorbital arch by cutting through the 142 PRACTICAL ANATOMY. internal and external angular processes of the frontal bone. (Fig. 96.) Carefully remove the bone without injuring the periosteum of the orbit. 2. Cut through the orbital periosteum and find, immediately under the peri- osteum, the frontal nerve. The frontal nerve lies on the levator palpebrae with the supraorbital artery and vein. It is a branch of the ophthalmic part of the fifth Internal rectus muscle Superior oblique muscle Trochlea Levator palpebrse superioris muscle, cut External rectus muscle Inferior oblique muscle Superior rectus muscle Levator palpebrae superior-is muscle, cut FIG. 96. VIEW OF LEFT ORBIT FROM ABOVE, SHOWING THE OCULAR MUSCLES (From Hirschfeld and Leveille. ) FIG. 97. MUSCLES OF THE EYE. I. Tendon of Zinn. 2. External rectus divided. 3. Internal rectus. 4. Inferior rectus. 5- Superior rectus. 6. Superior oblique. 7. Pulley for superior oblique. 8. Inferior oblique. 9. Levator palpebne superioris. 10, 10. Its anterior expansion. II. Optic nerve. nerve. You will see it divide into two branches: (i) the supratrochlear and (2) the supraorbital. The supratrochlear inosculates with the infratrochlear branch of the nasal nerve. The supraorbital comes through the supraorbital foramen, and is distributed to the forehead and inner part of the upper eyelid. The levator palpebrae superioris muscle (Fig. 97) lies under the preceding frontal nerve. It is inserted into the tarsal ligament of the upper lid. It lies orv THE HEAD AND NECK. 143 the superior rectus muscle. Cut the muscle in the middle, turn the ends out of the way, and expose the superior rectus muscle. (Fig. 96.) The Superior Rectus Muscle (Fig. 96). This muscle lies under the levator palpebrae. It is inserted into the sclerotic coat of the eyeball. Cut it, and turn the ends aside. You will see under this muscle a bed of fat. In the centre of the bed of fat and connective tissue is the optic nerve. (Fig. 103.) The Optic Nerve. To the outer side of this nerve you will see the external rectus muscle. Between the nerve and this muscle you will see the ciliary ganglion. Study the ciliary ganglion according to this outline (Fig. 98) : 1. Location between the optic nerve and external rectus muscle. 2. Size, about as large as a pin's head, but spider-like. 3. Roots : (i) A motor, from the branch of the third nerve to the inferior oblique; (2) a sensory, from the nasal nerve; (3) a sympathetic, from the cavernous plexus. 4. Distribution and function. Branches are given off from this ganglion, called the short ciliary nerves. They go with the optic nerve surrounding the LENTICULAR GANGLION SUPERIOR DIVISION OF THE THIRD NERVE NASAL H RANCH OF OPHTHALMIC SUPRAORKITAL NER VE SHORT CILIARY NER VES BRANCH OF THIRD TO INFER [OR OBLIQUE LONG ROOT OF LENTICU- LAR GANGLION 4 OPTIC NER VE THIRD NERVE SIXTH NERVE GASSERIAN GANGLION OPHTHALMIC DIVISION OF FIFTH NERVE SHORT ROOT OF SYMPA THETIC ROOT OF LENTICULAR LENTICULAR GANGLION GANGLION FIG. 98. NERVES OF THE ORBIT, FROM THE OUTER SIDE. (From Sappey, after Hirschfeld and Leveille.) same. On piercing the sclerotic coat they are joined by the long ciliary branches from the nasal nerve. (Fig. 98.) These branches are distributed to the iris and ciliary muscle. From wliat source does the ciliary ganglion derive its sympathetic influence, and hoi*.' docs the same enter the orbit ? It derives it from the superior cervical ganglion. The ascending fibres enter the cranium on the internal carotid artery. Here some fibres accompany the branches of this artery to the brain. Other fibres leave the artery in its cavern- ous stage, pass through the sphenoidal fissure to the orbit, and supply the ciliary or lenticular ganglion. Give the influence of paralysis of tlie third nerve on t/ie iris. Since the iris derives its motor influence, through the ciliary ganglion, from the third nerve, loss of power of contraction of the pupil would follow. The Optic nerve, you will find, is surrounded by very small nerves and arteries. (Figs. 98 and 103.) The nerves are: (i) Short ciliary, from the ciliary ganglion ; (2) long ciliary, from the nasal nerve. The arteries are ciliary, derived from the ophthalmic or some of its branches. The optic nerve derives its sheath from the dura mater. 144 PRACTICAL ANATOMY. The external rectus muscle lies to the outer side of the optic nerve. It is attended by the lachrymal nerve, a branch of the ophthalmic nerve, and the lachrymal artery, a branch of the ophthalmic artery. You will dissect the three together and associate them in your memory. The lachrymal structures are on their way to the lachrymal gland. Turn the external rectus muscle Tendon of superior oblique Trochlea Internal reotue Inferior oblique muscle Levator palpebrae super- ioris, cut Superior rectus External rectus Inferior rectu* FIG. 99. LEFT EYEBALL SEEN IN ITS NORMAL POSITION IN THE ORBIT, WITH VIEW OF THE OCULAR MUSCLES. (After Merkel, modified.) FIG. loo. MUSCLES OF ini. \-.\\-.. TENDON OR LK;AMKM OF /INN. I. Tendon of Zinn. 2. External rectus divided. 3. Internal rectus. 4. Inferior rectus. 5. Superior rectus. 6. Superior oblique. 7. Pulley for superior oblique. 8. Inferior oblique. 9. Levator palpebrse superioris. 10, 10. Its anterior expansion. II. Optic nerve. outward, and on its inner surface you will see the fine filaments of the sixth cranial nerve the abducens. The Superior Oblique Muscle and the Fourth Nerve (Fig. 97). These form a group by themselves. You will trace the tendon of this muscle around the trochlea, where it turns at a right angle and passes outward under the THE HEAD AND NECK. 145 superior rectus to be inserted into the sclerotica. You will find its nerve, the fourth, breaking up into a number of filaments on the ocular surface of the muscle. The nasal nerve crosses the optic nerve, passes under the superior rectus muscle, then passes between the superior oblique muscle and the internal oblique muscle. Here it gives off its infratrochlear branch to meet the supratrochlear branch of the frontal nerve. These two are sensory nerves. The nerve leaves the orbit by the anterior ethmoid foramen with the anterior ethmoidal artery. In the cranial cavity it lies under the dura, on the cribriform plate of the ethmoid bone. It passes through the nasal slit to the nasal fossae. In the nasal fossae it Superior reetus FOURTH NERVE \ Lsvator palpsbree superioris Lachrymal and frontal vein __SjM|K (#^lL f^~ Su P erior oblique . d f ge e ovfA a P hen C oi U d 8 al fr fls n sur i e brOU8 ~ T^S*1^~ PT1C F RA ^'^ A * D * Eli ' ' E Naso-ciliary of fifth nerve jlS*$_^ ~ Internal rectus SIXTH NERVED / \ ' N Inferior reetus External reotus THIRD NER VE FIG. 101. DIAGRAMMATIC REPRESENTATION OF ORIGINS OF OCULAR MUSCLES AT THE APEX OF THE RIGHT ORBIT. (After Schwalbe, slightly altered.) divides into branches : (i) Septal, to the mucous membrane of the septum ; (2) turbinals, to the turbinated bones. A small twig from the latter passes between the lower end of the nasal bone and its cartilage, and appears on the face as the naso-lobular a nerve of sensation, of course, to the wing and tip of the nose. TABLE OF ORIGIN OF OCULAR MUSCLES. NAME. ORIGIN. Levator palpebrae superioris, . Above optic foramen from lesser ala of sphenoid. Superior rectus, Upper margin of optic foramen. Inferior rectus, From ligament of Zinn. Internal rectus, From ligament of Zinn. External rectus, Upper head. Outer margin of optic foramen. External rectus, Lower head. From ligament of Zinn. Superior oblique, Above the optic foramen. Inferior oblique, Orbital plate of superior maxilla. The internal rectus and the inferior rectus may be brought into view by cutting the optic nerve and pushing the eyeball and the fatty mass forward. You will see these muscles taking their nerve-supply from the third nerve. Trace each muscle to its insertion into the sclerotica. The inferior oblique muscle arises from the orbital plate of the superior maxilla just external to the lower end of the lachrymal groove. It is inserted into the sclerotica, on the outer surface, in such a way as to antagonize the superior oblique muscle. Its nerve, the long branch of the third cranial, is of large size, and gives to. the ciliary ganglion its motor root. The orbital fascia invests the muscles. It passes forward on the tendons. In the vicinity of the globe it binds the tendons together by extending from one to another, thus forming, posterior to the ball, a loose double capsule the capsule of Tenon. This double layer forms a socket for the ball to move in. It separates posteriorly the fatty contents of the orbit from the globe of the eye. Describe the Ophthalmic Artery (Fig. 103). It is a branch of the inter- nal carotid artery. It enters the orbit by the optic foramen with the optic nerve. It is attended by the ophthalmic vein, which leaves the orbit by the sphenoidal 146 SKIN OF LOWER LID LOWER TARSUS Palpebral fascia and aat. lamina of muscle- fascia Orbicularis palpe- brarum Intension of sheath of inferior root us to lower eyelid FORNIX CONJUNCTIV/C Inferior oblique mu3ol3, cut across PERIORBITA Posterior lamina of muscle-fascia SUPRAVAGINAL SPACE CONTINUOUS WITH TENON'S SPACE SPACE OCCUPIED BY ORBITAL FAT, PRO- CESSES OF FASCIA SEPARATING THE LOBULES AND ENCLOSING BLOOD- VESSELS Inferior rectus PR A CTICAL ANA TO MY. \ SKIN OF UPPER LID UPPER TARSUS CORNEA Orbicularis palpe- brarum UPPER RIM OF ORBIT, WITH Splitting of periorbita Upper or anterior insertion of levator palpebrae Superior palpebral muscle of FORNIX CONJUNCTIV/E [Miiller Connection between levator palpebrae and sup. reetus, and fibres to conjunctiva PROCESS FROM PERIORBITA TO CAPSULE OF LACHRYMAL GLAND Superior rectus Levator palpebrae superioris Posterior lamina of muscle- fascia lined by prolongation of Tenon's capsule OPTIC NERVE FIG. 102. VERTICAL SECTION THROUGH THE EYEBALL AND ORBIT IN THE DIRECTION OF THE ORBITAL Axis, WITH CLOSED EYELIDS. (Semi-diagrammatic. After Schwalbe, modified to show fasciae.) Periorbita green ; muscle-fascia red; Tenon's capsule yellviv. Snpraorbital artery LACHRYMAL GLAND Superior rectus, cut EYEBALL External rectus Lachrymal artery Superior rectus, out Inferior ophthalmic vein Superior ophthalmic vein OPTIC NKR VI-: Common ophthalmic vein Commencement o/ superior ophthalmic vein Reflected tendon of superior oblique Ophthalmic artery Anterior ethmoidal artery Posterior ethmoidal artery Ciliary arteries Levator palpebrae, cut Ligament of Zinn iiilmic artery OPTIC COMMISSURE Internal carotid artery FIG. 103. TIIK OPHTHALMIC ARTKKV AND VEIN. THE HEAD AND NECK. 147 fissure and expands behind the sphenoidal fissure to form the cavernous sinus. Its branches are : 1. Lachrymal, with the external rectus, sixth nerve to lachrymal gland. 2. Supraorbital, with the frontal nerve, levator palpebrae, superior rectus. 3. Arteria centralis retinas, in centre of optic nerve to the retina. 4. Anterior ethmoidal, with the nasal nerve to ethmoid cells. 5. Posterior ethmoidal, to the posterior ethmoid cells. 6. Palpebral arteries, to the upper and lower lids. 7. Frontal artery, to the inner angle of the eye. 8. Nasal artery, to the lachrymal sac and caruncula. 9. Muscular branches, to the muscles of the eye. 10. Ciliary arteries, to the iris and choroid coat. Hew would you classify the nerves? 1 . Special sense : The optic nerve special of vision. ( Motor : Third, to all except two muscles. 2. < Motor : Fourth, to the superior oblique muscle. ( Motor : Sixth, to the external rectus muscle. T Sensory : Nasal branch of ophthalmic, to the nose and orbit. 3. < Sensory : Lachrymal branch of ophthalmic, to lachrymal gland. ( Sensory : Frontal branch of ophthalmic, to forehead. 4. Sympathetic, from cavernous plexus, to the ciliary ganglion. SUPERIOR LACHRYMAL GLAND INFERIOR LACHRYMAL GLAND DUCT FROM SUPERIOR 6LAND UPPER EYELID PARTIALLY DIVESTED OF SKIN UPPER PUNCTUM LACHRYMAL SAC, NEAR ITS FUNDt'S COMMON DUCT FORMED BY JUNC- TION OF CANALICULI UPPER AND LOWER CANALICULI LOWER PUNCTUM FIG. 104. LACHRYMAL APPARATUS. (After Schwalbe. ) The lachrymal gland you will find under the external angular process of the frontal bone in the lachrymal fossa. (Fig. 103.) It has an orbital and a palpebral part, a capsule, an artery, and a nerve. Define the periorbita and give its functions. This is the orbital periosteum. It forms the tarsal ligaments and the limbs of the inner palpebral ligament, lines the floor of the lachrymal groove, forms the trochleafor the superior oblique muscle of the eyeball, assists the orbital fascia in forming a capsule for the lachrymal gland, and sustains the orbital fat. Wliat is tJie first structiire you saw on removing the orbital plate of the frontal bone ? The periorbita or orbital periosteum, a continuation of the dura mater through the sphenoidal fissure and the optic foramen. On removing the periorbita, wliat did you sec f 1. In the middle we saw the frontal artery, a branch of the ophthalmic, and the frontal nerve, a branch of the ophthalmic division of the fifth nerve, lying on the levator palpebrae muscle. 2. To the outer side we saw the lachrymal artery, a branch of the ophthalmic i4 PRACTICAL ANATOMY. artery, and the lachrymal nerve, a branch of the ophthalmic division of the fifth nerve, lying on the external rectus muscle. 3. To the inner side we saw the fourth nerve, called also the patheticus, lying on and supplying the superior oblique muscle with motion, in its course having passed above the levator palpebrae muscle and the frontal nerve. Describe the frontal nerve, which you found on t/ie levator palpebrce, and tell what structure intervened bet'cvcen the periorbita and this nerve. The intervening structure was the peripheral part of the orbital fascia. It was so thin and translucent that we could see the nerve through the fascia. The frontal nerve is a branch of the ophthalmic part of the fifth nerve. About midway between the optic foramen and the supraorbital foramen it divides into a supra- orbital and a supratrochlear branch. The supraorbital branch leaves the orbit through the supraorbital foramen and supplies the skin of the upper lid, the skin of the forehead, and the pericranium in this same region ; the supratroch- lear branch communicates with the infratrochlear branch of the nasal nerve around the pulley for the superior oblique muscle, branches being given off from this loop to supply the upper lid, forehead, and nose. Describe the lachrymal nerve, which you saw on the external rectus muscle. It is a branch of the ophthalmic part of the fifth nerve. It gives branches to the lachrymal gland, and to the skin and mucous membrane of the upper lid, and sends a communicating branch to the orbital branch of the superior maxillary nerve. Describe the nasal nerve. It is a branch of the ophthalmic. It has a most complicated course, which to be learned thoroughly must be studied according to these stages : 1. The nerve enters the orbital cavity by the sphenoidal fissure. 2. In its course through the orbit it passes : (i) Between the optic nerve and superior rectus muscle ; (2) between the external rectus muscle and the superior oblique muscle, and arrives at the anterior ethmoidal foramen. In this, its orbital stage, the nerve gives off the long root to the ciliary ganglion, at the sphenoidal fissure, and the long ciliary nerves to the eyeball, as it crosses the optic nerve. At the anterior ethmoidal foramen the nerve gives off the infratrochlear branch, to communicate with the supratrochlear branch of the frontal nerve. 3. In company with the anterior ethmoidal artery it enters the cranial cavity, by the anterior ethmoidal foramen, crosses the cribriform plate of the ethmoid bone, and leaves the cranial cavity and gains the nasal cavity by the nasal slit, by the side of the crista galli. 4. The nerve divides in the nasal cavity into septal branches, which are dis- tributed to the upper and front part of the septum nasi, and branches to the outer wall and anterior ends of the two lower turbinals. The end branch of this nerve passes between the cartilage and the end of the nasal bone, supplying the tip and lobe of the nose. Describe the motor oculi, or third cranial nerve. This nerve is the most important motor nerve to the muscles of the orbit. As the nerve emerges from the cavernous sinus it divides into a superior and an inferior division, which enter the orbit by the sphenoidal fissure. The superior division supplies the levator palpebrae and superior rectus muscles. The inferior division supplies the internal rectus, the inferior rectus, and the inferior oblique. The third nerve supplies with motion the circular fibres of the iris and the ciliary muscle, through the ciliary ganglion. Describe the fourth crania! nerve. It is called patheticus and trochlear. It enters the orbit by the sphenoidal fissure, passes above the frontal nerve and levator palpebras muscle, and is distributed to the superior oblique muscle. This is the smallest of the cranial nerves. THE HEAD AND NECK. 149 Describe the sixth cranial nerve. It is called the abducent nerve. It enters the orbit by the sphenoidal fissure, between the two heads of the external rectus, to which muscle it is distributed. Describe the optic nerve. This is the nerve of the special sense of sight. It is the second cranial nerve. It enters the orbit by the optic foramen, internal to and above the ophthalmic artery. It pierces the ball of the eye and forms the retina. It is surrounded by the ciliary vessels and nerves. To its outer side is the ciliary ganglion. At the optic foramen it is surrounded by the four recti muscles. The arteria centralis retinae pierces its under surface and goes to the interior of the eyeball. The process of dura that surrounds the nerve divides in such a manner as to form a sheath for the nerve, and also the orbital periosteum, inside the orbit. The optic sheath is continuous with the sclerotica. Wliat is the orbital fascia? It is a variety of connective tissue, being to the contents of the orbit what the deep fascia is to the thigh. It forms a capsule, in conjunction with the peri- orbita, for the lachrymal gland, and sheaths for the muscles, vessels, and nerves. It is connected to the ocular conjunctiva close to the cornea. The muscular sheaths are firmly adherent to the muscles. The insertions of the ocular muscles into the sclerotica are connected together around the whole circumference of the globe. From this attachment this fascial connecting medium is reflected backward in a double layer, forming the fibrous basis of a serous membrane the visceral layer covering the back part of the globe, the parietal lining the postocular fat in the orbit. A layer of endothelial cells completes the serous membrane. Here we have a visceral layer, a cavity, and a parietal layer, the three cardinal points in any serous apparatus. This reflected part of the orbital fascia permits free movement of the eyeball, as the head of a bone revolves in its socket, and is known in anatomy as the capsule of Tenon. By what is the orbital fascia on the posterior part of the eyeball pierced ? It is pierced by the vessels and nerves that supply the globe. What muscle did you find immediately under the levator palpebrce ? The superior rectus, and under this we found the optic nerve, surrounded by fat, vessels, and nerves. Name the muscles of the eyeball and give their function. The external rectus abducts the cornea. The internal rectus adducts the cornea. The superior rectus elevates, adducts, and rotates cornea inward. The inferior rectus depresses, adducts, and rotates cornea outward. The superior oblique depresses, abducts, and rotates cornea inward. The inferior oblique elevates, abducts, and rotates cornea outward. The levator palpebrae elevates the upper eyelid. Name all the nerves that supply the orbital contents. The optic, the nerve of special sense of sight. The motor oculi, a motor nerve to all muscles except two. The pathetic, a motor nerve to the superior oblique muscle. The abducens, a motor nerve to the external rectus muscle. The frontal, a branch of the ophthalmic of the fifth nerve. The lachrymal, a branch of the ophthalmic of the fifth nerve. The supratrochlear branch of the frontal. The palpebral branches of the frontal. The infratrochlear branch of the nasal. The long ciliary branches of the nasal. The short ciliary branches of the lenticular ganglion. The cavernous sympathetic branches to lenticular ganglion. 150 PRACTICAL ANATOMY. The lenticular or ciliary ganglion. \VIiere is tlic ciliary ganglion located, and how is it formed .' It lies between the external rectus muscle and the optic nerve on the outer side of the ophthalmic artery. It is the size of a pin's head. It has three roots : 1 . A sensory root from the nasal nerve. 2. A motor root from the motor oculi nerve. 3. A sympathetic root from the cavernous sympathetic. Hoiv do the nerves gain access to the orbit ? The optic nerve passes through the optic foramen ; all the others pass through the sphenoidal fissure with the ophthalmic vein. Name all the structures seen on inspecting the eye of a patient. 1. The palpebral fissure, a slit between the lids. 2. The outer and inner canthi, the extremities of the fissure. 3. The tarsal cartilages, the free margins of the lids. 4. The cornea, behind, which is the iris. 5. The pupil, surrounded by the iris.- 6. The tendo oculi, or inner palpebral ligament. 7. The lachrymal caruncle, just within the inner can thus. 8. The superior palpebral fold when the eye is opened. 9. The inferior palpebral fold when the eye is opened. 10. The palpebral and ocular conjunctivae. i i. The conjunctival cul-de-sac or fornix. 1 2. The sclerotica, or white of the eye. 13. The conjunctival sac. This is the space between the posterior surface of the lid and the eyeball. It is completely covered by conjunctiva. A patient gets a cinder in his eye : What nerve or nerves report the pain to the brain f The cornea and sclerotica are supplied by the ciliary nerves. The infra- trochlear branch of the nasal nerve supplies the conjunctiva, the lachrymal sac, and the caruncula lachrymalis. The lachrymal nerve sends conjunctival branches to the upper lid. The palpebral branches of the superior maxillary send con- junctival branches to the lower lid. While, then, a number of branches are con- cerned locally, one nerve, the trigeminus or fifth, does terminal work for all, since the lachrymal, nasal, superior maxillary, and the sensory root of the ciliary ganglion are all derived from the fifth nerve. A reflex circuit is completed by the seventh nerve, acting on the orbicularis palpebrarum to close the eye. Emissary Foramina and Their Veins. Define emissary foramina ami emissary veins. Emissary foramina derive their importance from the veins they transmit ; emissary veins are both physiologically and pathologically important. The emis- sary veins are connected centrally to the sinuses in the dura mater ; peripherally they communicate with veins both deep and superficial. From a physiological standpoint these veins regulate indirectly the arterial pressure in the brain, since, in cases of cerebral engorgement, when the internal jugular veins are unable to convey the required amount of blood in the dural sinuses from the brain, the emissary veins deliver large quantities of this venous blood to the superficial or to the deep veins with which they communicate peripherally. This action of the emissary veins has been compared to a safety-valve in mechanics. From a pathological standpoint these veins are conveyers of septic material from areas accessible to the surgeon and physician, to regions beyond the reach of either. Infection in the orbit, posterior nares, and scalp over the forehead reaches the cavernous sinus via the angular and ophthalmic veins. Infection in the face, nose, and teeth reaches the cavernous sinus via the Vesalian vein and pterygoid THE HEAD AND NECK. 151 plexus. The conservatism of emissary veins is well illustrated in the profuse epistaxis of children, incident to cerebral congestion. In this case an emissary vein connects centrally the blood in the superior longitudinal sinus with the blood in the mucous membrane of the nose ; the latter, being the weaker structure, gives way, and the arterial pressure in the brain is relieved by a profuse hemor- rhage. The emissary foramina seem to belong more especially to the physio- logical needs of childhood. .The greater number of emissary veins and their foramina disappear as adult years come on. By osteological classification these foramina are inconstant. The following table gives a list of the emissary foramina, the central sinuses, and the peripheral veins, between which the emissary veins stand, holding the two together like the handle connects the two globes of a dumb-bell : TABULATED LIST OF EMISSARY STRUCTURES. FORAMEN. CENTRAL SINUS. PERIPHERAL VEIN. Caecum Superior longitudinal, Nasal mucous membrane. Carotid canal, Cavernous, Internal jugular vein. Parietal, Lateral, Occipital. Vesalii, Cavernous, Internal jugular vein. Posterior condylar, Lateral, Deep cervical. Occipital, Torcular Herophili, Occipital veins. Anterior condylar Occipital, Deep cervical. Mastoid, Lateral, Occipital veins. Sphenoidal fissure Cavernous, Angular and ophthalmic. Ovale Cavernous, Pharyngeal and pterygoid. How SEPTIC THROMBI REACH THE SINUSES. How may a carbuncle of tJie face, or facial erysipelas, or infection of tJie scalp over the forehead result in fatal blood-poisoning ? Septic thrombi from these sources- may reach the cavernous sinus and get beyond the reach of the surgeon. The frontal and supraorbital veins unite to form the angular, and this is one of the large tributaries of the facial vein. (Fig. 1 8.) Now, the angular vein communicates with the ophthalmic. The ophthalmic vein passes through the sphenoidal fissure, and is tributary to the cavernous sinus. The angular, facial, and ophthalmic veins contain no valves, hence the blood can pass either forward or backward from the superficial seat of infection to a region beyond the reach of surgical drainage and antisepsis. Tell the course septic material from a carious tooth, alveolar abscess, or suppura- tion of the antrum folloius in cases of fatal blood-poisoning- to reach the sinuses in the dura mater beyond the reacli of operative procedure. To appreciate an answer to this question you must recall the distribution of the internal maxillary artery to the muscles of mastication, the teeth, the nasal fossae, the meninges, and the palate. Now, the veins returning the blood from these areas take the course of their companion arteries, and the same name as the arteries. The veins from these regions, the small and great meningeal, the supraorbital and posterior dental, the palatine and spheno-palatine, the deep temporal, ptery- goid, and buccal, the lower ophthalmic and Vesalian, all come together on the inner surface of the internal pterygoid muscle to form the pterygoid plexus. This plexus communicates with the cavernous sinus by the Vesalian vein. As these veins contain no valves, septic thrombi originating anywhere in the dental, alveolar, antral, nasal, or palatine regions may spread backward to the cavernous sinus via the Vesalian vein and pterygoid plexus. SHOULDER, ARM, FOREARM, AND HAND. I prefer to have my students begin a dissection of the upper extremity on the fingers and hand. The liability of these parts to become dry, to say nothing of the great practical importance of this region, is sufficient apology. Any dis- section of the hand without a review of the salient osteological landmarks will be, in a measure, a poor dissection, unsatisfactory alike to teacher and student. The student should become master of the following points in osteology before he begins work on the cadaver : OSTEOLOGICAL POINTS ON THE HAND. The Carpus and Hand (Figs. 108 and 109). Name the points on the bones of the carpus and hand of importance in practical anatomy. The carpo-metacarpal articulations. The base of the first or thumb metacarpal. The base of the second metacarpal, radial side. The base of the third metacarpal, radial side. The base of the fifth metacarpal, ulnar side. The pisiform bone of the carpus. The groove in the os trapezium. The unciform process of the unciform bone. The base of the first thumb phalanx. The base of the second thumb phalanx. The dorsal bases of index, middle, and ring fingers. The dorsal bases of second and third phalanges. The palmar bases of second and third phalanges. What is the importance of the groove in the os trapezium at the base of the thumb f It transmits the tendon of the flexor carpi radialis to its insertion into the base of the index metacarpal bone. What is the importance of the base of the fifth metacarpal ? On its palmar side is inserted the flexor carpi ulnaris ; on its dorsal the ex- tensor carpi ulnaris. These muscles are antagonized by radial and ulnar carpal extensors. Name the radial and ulnar extetisors of tJie carpus. There are two radial extensors of the carpus : the extensor carpi radialis longior and brevior, inserted into the bases of the second and third metacarpals respectively, on the radial side. The extensor carpi ulnaris is inserted into the base of the fifth metacarpal on the ulnar side. Give the importance of the pisiform bone and the unciform process of the unciform bone on the ulnar side of the carpus, in conjunction ~^ilh t/ic scaphoid and trapezium on the radial side. It is these bones that give attachment to the anterior annular ligament of tlu- 152 SHOULDER, ARM, FOREARM, AND HAND. 153 wrist, a band of deep fascia that binds down the strong flexor tendons of the fingers and thumb, and also preserves the transverse carpal arch. Pectoralis major, hooked up External jugular vein Pectoralis major Lymphatics from side of chest Pectoral glands Basilic vein ven r, Epitrochlear gland 1 ial ulnar ' Posterior superficia vein Median basilic vein Inner set of superficial lym- phatics of forearm Deep median vein INTERNA L CUTA NEO US NER VE Anterior superficial ulnar vein Median set of superficial lym- phatics of forearm Supraclavicular gland Jugulo-cephalic vein Deltoid muscle Lymphatics accompanying cephalic vein Axillary glands Cephalic vein Lymphatic vessels of inner side of arm Biceps, exposed MUSCULO-CUTANEO US NER VE Brachial artery Bicipital fascia Median cephalic vein Superficial radial vein Superficial median vein Outer set of superficial lym- phatic vessels of forearm FIG. 105. SUPERFICIAL VEINS AND LYMPHATICS OF THE FOREARM AND ARM. What is on the palmar surface of the phalanges ? A groove limited laterally by a ridge of bone on each side. The groove is converted into an osseo-aponeurotic canal by a strong covering of deep digital 154 fascia, called the ligamentum vaginale. In this canal are found the flexor ten- dons, invested by a synovia! membrane called theca. ANTERIOR PART. Locate on the cadaver : (i) The clavicle ; (2) the sternum ; (3) sterno-clavicu- lar articulation ; (4) acromio-clavicular articulation ; (5) the acromion ; (6) the coracoid process ; (7) the greater tuberosity of the humerus ; (8) the lesser tuberosity of the humerus ; (9) the internal condyle ; (10) the external condyle ; (i i) the radial head 5(12) the clefts of the fingers ; (13) the thenar eminence ; INTERNAL CUTANEOUS OF MUSCULO- SPIRAL INTERNAL CUTANEOUS PALMAR CUTANEOUS OF MEDIAN PALMAR CUTANEOUS OF ULNAR SUPRA- ACROMIAL CIRCUMFLEX INTERCOSTO- HUMERAL TWIG OF INTERNAL CUTANEOUS CIRCUM-\ FLEX 1 EXTERNAL CUTANEOUS OF MUSCULO- SPIRAL MUSCULO- CUTANEOUS EXTF.RNAL CUTANEOUS OF MUSCULO- SPIRAL MUSCULO- CUTANEOU* RADIAL PALMAR CUTANEOUS OF RADIAL SUPRA- ACROMIAL INTERNAL cr r TA\EOUS OF MUSCULO- SPIRAL INTERCOSTO- HL'MERAL NERVE OF WRISBERQ INTERNA L CUTANEOUS ULNAR FIG. 106. DISTRIBUTION OF CUTANEOUS NERVES ON THE ANTERIOR AND POSTERIOR .Asn-rrs OF THE SUPERIOR EXTREMITY. (14) the hypothenar eminence; (15) the metacarpo-phalangeal articulation; (16) the phalangeal articulations; (17) the pisiform; (18) the unciform pro- cess of the unciform bone. Incisions. (i) From the acromion to the end of the middle finger ; (-2) from the sterno-clavicular articulation to the acromion ; (3) from condyle to condyle ; (4 through the metacarpo-phalangeal crease. NOTE. In making these incisions care must be taken not to cut too deeply, in order to avoid doing violence to the cutaneous vessels and nerves. Now remove the skin very carefully and expose the following cutaneous nerves and veins : I. The ccpJialic vein a continuation of the radial above the elbow. (Fig. 105.) SHOULDER, ARM, FOREARM, AND HAND. 155 2. The basilic vein a continuation of the ulnar above the elbow. 3. The superficial radial vein, on radial side of forearm. 4. The superficial median vein, on midfront of forearm. 5. The anterior superficial nlnar vein, on ulnar side of forearm. 6. The posterior superficial ulnar vein, on posterior part of forearm. 7. The deep median vein, a communicating vessel. 8. The external jugular vein, seen above the clavicle. Cutaneous Nerves. 1. The palmar cutaneous branch of the ulnar nerve, supplying 1.5 fingers. 2. The palmar cutaneous branch of the median nerve, supplying 3.5 fingers. 3. The palmar cutaneous branch of the radial nerve, to ball of thumb. THnar portion of palmar bursa Radial portion of palmar buraa Anterior annular ligament Lumbricalis Deep transverse ligament Superficial transverse ligament FIG. 107. DIAGRAM OF THE GREAT PALMAR BURSA. 4., The cutaneous branch of the musculo-cutaneous nerve. 5. The internal cutaneous nerve on internal part of the forearm. 6. The intercosto-humeral nerve on internal part of the arm. 7. The cutaneous brancJi of 'the circumflex nerve over insertion of deltoid. 8. The internal cutaneous branch of the muscido-spiral nerve. Directions for Dissecting the Cutaneous Vessels and Nerves. Consult figures 105 and 1 06. Plow through the upper fat-bearing strata of the superficial fascia with the forceps never with the scalpel. You will find all the vessels and nerves in the deep layer of the superficial fascia. Divide the fascia in the direction of the vessels and nerves. The radial veins converge to form the cephalic vein above the elbow. 156 PRACTICAL ANATOMY. (Fig. 105.) The ulnars converge to form the basilic vein above the elbow. The medians converge to form one large vein. This vein breaks up into the median ccpJialic and median basilic, which join respectively the cephalic and basilic veins. (Fig. 105.) Observe that the internal cutaneous nerve passes behind the median basilic vein ; that the cutaneous branch of the musculo-cutaneous nerve passes behind the median cephalic vein. (Fig. 105.) Find the deep median vein, piercing the deep fascia near the bifurcation of SEMILUNAR ISIFORM EIFORM Extensor carpi radialis longior Extensor carpi radialia brevier Extensor carpi ulnarii Extensor oommunis digitorum Extensor oommunis digitorum THIRD, UNGUAL, OR TERMINAL PHALANX FIG. 108. THE LEFT HAND. (Dorsal surface.) the superficial median vein. Trace it to the ulnar vein below the deep fascia. (Fig. 105.) Note that the median basilic vein crosses the lower part of the bracliial artery. Notice also the bicipital fascia between these two structures. (Fig. 105.) This vein was formerly a favorite in bleeding. The basilic vein termin- ates in the axillary ; the cephalic in the axillary vein also. Find the cephalic vein in a groove between the pectoralis major and deltoid muscles with the 'Irscending branch of the acromio-thoracic artery below the clavicle. SHOULDER, ARM, FOREARM, AND HAND. 157 The cutaneous branch of the musculo-cutaneous nerve supplies the skin over the insertion of the biceps ; inasmuch as the supinator longus is also a flexor of the forearm, and receives a part of its nerve-supply from the musculo-cutaneous nerve, the skin over the insertion of this muscle is also supplied by the same nerve. See Hilton's law in the introductory chapter. Plexor brevis pullieia Abductor pollicis Flexor carpi ulnaris Abductor minimi digiti Flexor brevis and opponens minimi digiti Flexor carpi ulnaris Adductor pollicis Opponens minimi digiti Abductor and flexor brevis minimi digiti Opponens pollicis Occasional insertion into trapezium Extensor oasis metacarpi pollicis Flexor carpi radialis Interosseus primus volaris Opponens pollicis Flexor brevis and Abductor pollicis Flexor brevis and Adductor pollicis Flexor longua pollicis Flexor sublimis digitorum Flexor profundus digitorum FIG. 109. THE LEFT HAND. (Palmar surface.} DEEP FASCIA OF THE HAND. The deep fascia fascia profunda lies immediately under the superficial fascia, being in intimate trabecular relation with the deep layer of the superficial fascia. In the palm of the hand it is very dense and heavy ; over the thenar and hypothenar eminences it is very thin. The deep fascia takes the following special names : 1. The anterior annular ligament in front of wrist. 2. The palmar fascia in palm of the hand. 3. The ligamenta vaginales on flexor side of the digits. 158 PRACTICAL ANATOMY. 4. Internal and external intermuscular fascia. 5. The posterior annular ligament. 6. The dorsal fascia of the hand. Flexor carpi radialis Flexor carpi ulnaris Deep fascia of forearm Extensor oasis metacarpi pollicis ^ Opponens pollicis Abductor pollicis Flexor brevis pollicis Adductor Follicle First lum- bricalis - First dorsal interos- seoua Iiigamentum vaginale Flexor sublimis digitorum Flexor profundua digitorum Flexor profundus digitorum FIG. no. THE SUPERFICIAL MUSCLES OK THE PALM OK THE HAND. Dissection of the Jiand in which find the following : 1. The palmar fascia and palmaris brevis muscle. 2. The flexor tendons and their sheaths and vincula. 3. The digital nerves and arteries and digital veins. 4. The superficial palmar arch and its branches on flexor tendons. 5. The thecal culs-de-sac, synovial in the ligamenta va;^inalis. SHOULDER, ARM, FOREARM, AND HAND. *59 6. The anterior annular ligament on front of carpus. 7. The musculi lumbricales on flexor tendons. 8. The thenar and hypothenar muscles about thumb and little finger. 9. The deep palmar arch and branches below the flexor tendons. 10. The deep palmar branch of the ulnar nerve with deep arch. 1 1. The dorsal interossei muscles. 12. The ulnar nerve in the hand, supplying 1.5 fingers. 13. Deep palmar arch and branches of ulnar nerve in the hand. 14. The median nerve in the hand, supplying 3.5 fingers. 15. The radial and ulnar arteries in the hand, forming the arches. 1 6. The palmar interosseous muscles on the palmar surface. Dissection. The palmar fascia is the deep fascia of the flexor surface of the MEDIAN NERVE BRANCH TO MUSCLES OF THUMB COLL A TERAL BRANCHES OF MEDIAN ULNAR NERVE COMMUNICA TION BETWEEN MEDIAN AND ULNAR COLLATERAL BRANCHES OF ULNAR FIG. in. SUPERFICIAL NERVES OF 'IHE PALM. (Ellis.) hand from the annular ligament above to the clefts of the fingers below. Having removed the skin of the palm, and noticed the granular fat in the superficial fascia thereof, you are now ready to study the palmar fascia. This fascia has three divisions : (i) An inner thin part that covers the muscles forming the ball of the little finger ; (2) an outer thin part that covers the muscles forming the bail of the thumb ; (3) a central strong portion, investing the central distributory region of the hand, in such a way as to protect the vessels and nerves for the supply of the fingers and adjacent structures. The palmar fascia is continuous above with the anterior annular ligament, and below with the ligamenta vaginales in the form of heavy protective sheaths for the flexor tendons of all the fingers. Figure 1 10 shows this ligamentum vaginale still intact in the little finger. The Flexor Tendons and Ligamenta Vaginales. Cut through the very i6o PRACTICAL ANATOMY. centre of the dense ligaincnta vagitialcs and you will come down on the two flexor tendons. Notice that the tendon of the flexor profnndus digitontui passes through a slit in the tendon of the flexor snbliinis digitornin. (Fig. 1 10.) The former is inserted into the base of the third, the latter into the base and sides of the second phalanx. Now gently separate these tendons and you will see (i) the visceral layer of synovial membrane on the tendons, and (2) the vincula delicate tendinous cords. Flexor carpi ulnaria Abductor minimi digiti Flexor sublimis digitorum Flexor brevis minimi digiti Flexor prot'undus digitorum Extensor oasis metacarpi pollicis Flexor carpi radialis Extensor brevis pollicis Abductor pollicis Opponens pollicis Abductor pollicis Flexor brevis pollicis FIG. 112. THE DEEPER MUSCLES OK THE PALM OK THE HAND. These heavy, deep fascial sheaths you have just cut through are lined by synovial vaginal membrane called the theca. In the thumb and little finger these synovial cavities communicate with the ulnar and radial palmar bursae above the annular ligament. (Fig. 107.) The thecre for the remaining fingers terminate in thecal culs-de-sac opposite the metacarpo-phalangeal articulations. (Fig. 107.) Infection in the thumb and little finger thus is liable to travel beyond the annular ligament, while in the other fingers it would be arrested at the culs-de-sac. SHOULDER, ARM, FOREARM, AND HAND, 161 A case of unusual interest, bearing on this point, reported by Dr. David Loring, of Valparaiso, Indiana, is as follows : " Infection ensued where a patient thrust a nail through the anterior annular ligament. One by one all the carpal bones, the bones of the thumb and the little finger, and the greater part of the metacarpals disappeared by suppuration. At the present time the patient is well, and has the bones of all the fingers between the thumb and little firmer." This case is of Anterior inlerosseous Radial artery Anterior radial carpal Svperficial rolar Posterior radial carpal Radial artery at wrist Dorsalis potUcis MKtacar/nil or first dorsal inlerosseous Princepspollicis Dorsalis indicts Jladialis indicis First dorsal branch of collateral digital Second dorsal branch of collateral digital Anastomosis of collateral digital arteries about matrix of nail and pulp of finger Ulnar artery Anterior ulnar carpal Posterior ulnar carpal Deep ulnar Superficial arch Carpal recurrent Posterior communi- cating or perforat- ing Palmar interosseous Second, third, and fourth palmar digital Second and third dorsal interosseous First palmar digital Anterior communi- cating or perforat- ing FIG. 113. ANASTOMOSES AND DISTRIBUTION OF THE ARTERIES OF THE HAND. interest because the pathological process followed to the letter the anatomical rule. The vincula will be seen between the flexor tendons. They are delicate, sil- very, tendinous threads. They aid the capillaries in passing from -one tendon to another. They are, then, mechanical devices for the support of the capillaries that nourish the synovial membrane. In some cases the vessels which they support are injected, and can be seen by the unaided eye. The palmaris brevis muscle (Fig. 110) arises from the annular ligament 1 62 PRACTICAL ANATOMY. and palmar fascia, and is inserted into the skin of the hypothenar eminence. It is a corrugator of the integument. The anterior annular ligament (Fig. 1 1 1) has passing under it the follow- ing structures : 1. The median nerve and its nutrient artery arteria comes nervi mediani. 2. The flexor sublimis digit or nm musculus perforatus. 3. The flexor prof undus digitorum musculus perforans. 4. The flexor longus po llicis between the heads of the flexor brevis. To the inner side of the anterior annular ligament, and intimately related thereto, you will find the flexor carpi ulnaris ; to the outer side, the flexor carpi radialis. Inserted into the anterior annular ligament, and passing in front of the same, is the palmaris longus muscle. (Fig. 1 10.) To the ulnar side is the ulnar, and to the radial side is the radial, artery. (Fig. 117.) This anterior annular ligament is a specialized part of the deep fascia. It is attached internally to the pisiform bone and unciform process of the unciform bone; externally, to the scaphoid tuberosity and os trapezium. (Fig. 109.) Cut through the annular ligament ; pull the sides forcibly apart as far as pos- sible. There are two portions of the palmar bursa : (i) The radial, correspond- ing to the flexor longus hallucis ; (2) the ulnar, corresponding to the flexor sublimis digitorum and flexor profundus digitorum. (Fig. 107.) To Dissect the Median Nerve in the Hand (Fig. 1 1 1). You will now see the median nerve, as large as a lead-pencil, lying on the flexor sublimis digitorum. This nerve is involved in the synovial membrane, and it will require the aid of the forceps to liberate the same. Place your left index finger under the nerve, carefully lifting the same upward ; now begin to trace out the following branches (Fig. in) : (i) To the thumb ; (2) to the index finger, the middle finger, and radial side of the ring finger ; (3) a communicating branch to thje ulnar nerve. You will see these branches given off from an enlargement. Trace the branches downward and observe them passing behind the superficial palmar arch. (Figs. 1 1 1 and 1 13.) The branches of the median nerve, after passing behind the superficial palmar arch, accompany arterial branches of the superficial and deep palmar arches to the fingers. (Fig. in.) These arteries and nerves are called digital branches. Note that at the superficial palmar arch the nerves lie behind, but in the fingers the nerves lie in front of, the arteries. Trace these digital arteries and nerves to the ends of the finger, and see the distal digital anastomotic arterial arch. (Fig. 1 13.) The Ulnar Nerve in the Hand. Find the ulnar nerve crossing the annular ligament (not under it). It lies to the ulnar side of the ulnar artery, and some- what deeper. Trace it down and find it dividing into two branches : (i) The superficial palmar ; (2) the deep palmar. The former gives off branches to the skin, to the palmaris brevis muscle, and digital branches which accompany arteries to the little finger and one-half of the ring finger. Trace these branches to the finger end and observe the distal digital anastomotic nerve loop. ( Fig. ill.) The deep palmar branch of the ulnar nerve accompanies the deep arch, and will be described in its proper place on page 164. The musculi lumbricales (Fig. 112) are four in number. Cut the tendons of the flexor sublimis as shown in figure 112. These muscles arise from the tendons of the flexor profundus digitorum muscle. Trace them on the thumb side, to the extensor communis digitorum, where they are inserted. The ulnar two interossei muscles are supplied by the ulnar, the radial two by the median, nerve. The thenar muscles, or muscles of the thumb (Figs. 109 and 114): i. The abductor pollicis, abducts first phalanx. SHOULDER, ARM, FOREARM, AND HAND. 163 2. The flexor brevis pollicis, flexes first phalanx. 3. The opponens pollicis, acts on metacarpal. 4. The adductor pollicis, adducts the first phalanx. The abductor pollicis (Fig. iio)is easily isolated. Cut the same near its insertion, and turn it aside so as to preserve the nerve-supply. (Figs. 109 and 114.) This muscle arises from the bone at the base of the thumb the os trapezium and the annular ligament. It is inserted into the base of the thumb, proximal phalanx. (Fig. 109.) The opponens pollicis is inserted into the whole length of the thumb meta- carpal bone. (Fig. 109.) It arises from the os trapezium and annular ligament. (Fig. 114.) Flexor carpi ulnaris Pronator quadratus Abductor pollieis Outer head of flexor brevis pollicis Inner head of flexor breyis pollieis (first division) Opponens pollicis Inner head of flexor breyis pollicis (third division) Inner head of flexor breyie pollicis (second division) Adductor pollicis Dorsal interoaseous Third palmar interosseoua Fourth dorsal mterosseous Second palmar iuterosseous First palmar interoaseous Third dorsal intsrosseous Second dorsal interoaseous FIG. 114. THE PRONATOR QUADRATUS AND DEEP VIEW OF THE PALM. Tlie flexor brevis pollicis has two heads, and between these two heads lies the tendon of the flexor longus pollicis muscle. The outer, or more superficial head (Fig. 114), arises from the os trapezium and annular ligament, and is inserted into the base of the first thumb phalanx on the outer side. (Fig. 109.) The deep or inner head has two parts : (i) A small part that arises from the first metacarpal bone ; (2) a large part that arises from the annular ligament, the os magnum, and the second and third metacarpals. (Fig. 1 14.) This latter is described by some authors as the oblique part of the adductor pollicis. The deep part of the flexor brevis is inserted into the base of the first thumb phalanx on the inner side. 164 PRACTICAL ANATOMY. The adductor pollicis is the remaining muscle. It arises from the mctacarpal bone of the middle finger, the lower two-thirds. It is inserted into the base of the first thumb phalanx on the inner side. (Fig. 1 14.) Nerve-supply. The median nerve supplies the abductor pollicis, the opponens, and the outer head of the flexor brevis pollicis. The ulnar nerve, by its deep palmar branch, will supply all the remaining muscles of the hand, all the inter- ossei muscles, the two ulnar lumbricals, the little finger group of small muscles, the adductor pollicis, and the inner head of the flexor brevis pollicis. Now trace out and review the branches of the median nerve to the thumb. The hypothenar muscles, or muscles of the little finger (Fig. 114): 1. The abductor minimi digiti abducts the little finger. 2. The flexor brevis minimi digiti bends the first phalanx. 3. The opponens minimi digiti bends the metacarpal. FIG. 115. THE PALMAR INTEROSSEI. The abductor minimi digiti arises from the pisiform bone. (Fig. 109.) inserted into the base of the first phalanx of the little finger. (Fig. 109.) and turn aside, and expose the two remaining muscles the flexor brevis minimi digiti and the opponens minimi digiti. Note, as you turn this muscle aside, the abductor minimi digiti the d palmar nerve going to join the deep palmar arterial arch from the radial arte (Fig. 1 1 6), whose course it will now follow. The flexor brci'is minimi digiti arises from the unciform process of the unci- form bone and annular ligament. It is inserted into the base of the first phalan of the little finger. (Fig. 109.) The opponens minimi digiti arises from the unciform process of the uncifor bone and annular ligament. It is inserted into the whole length of the met carpal bone of the little finger. Trace branches from the deep palmar branch the ulnar nerve to this group of muscles. (Fig. 1 1 1.) SHOULDER, ARM, FOREARM, AND HAND. 165 The Palmar Interossei Muscles (Figs. 114 and 115). These are three in number. They are physiological adductors. They arise from one side of the metacarpal bone corresponding to the finger, into the base of whose proximal phalanx they are inserted. They are inserted into the bases of the proximal phalanges of the index, little, and ring fingers in such a way as to adduct these fingers to the middle finger. Trace branches to them from the deep palmar branch of the ulnar nerve. The Deep Palmar Branch of the Ulnar Nerve. You have seen the ulnar Anterior inter osseous Radial artery Anterior radial carpal Superficial volar Posterior radial carval Radial artery at wrist Dorsalis pollicia Metacarpal or first dorsal iiiterosseorts Pi-inceps pollici-s Dorsalis indicis Radialis indicis Ulnar artery Anterior ulnar carpal Posterior ulnar carpal Deep ulnar Superficial arch Carpal recurrent Posterior communi- cating or perforat- ing Palmar inlerosseous Second, third, and fourth palmar digital Second and third dorsal interosseous First palmar digital A nterior communi- cating or perforat- ing First dorsal branch of collateral digital Second dorsal branch of collateral digital Anastomosis of collateral digital arteries about matrix of nail and pulp of finger FIG. 116. ANASTOMOSES AND DISTRIBUTION OF THE ARTERIES OF THE HAND. nerve crossing the anterior annular ligament, and dividing, below the pisiform bone, into superficial and deep palmar branches. (Fig. in.) You traced the superficial branches to the palmaris brevis, the skin over the hypothenar emi- nence, and to the little finger and half the ring finger. (Fig. 1 1 1.) You will now trace in review the deep palmar branch, between the abductor minimi digiti and flexor brevis minimi digiti, and see it join company with the deep palmar arterial arch, and send off branches to these muscles : 1 66 PRACTICAL ANATOMY. 1. The abductor minimi digiti muscle. 2. The flexor brevis minimi digiti muscle. 3. The opponens minimi digiti muscle. 4. The two ulnar lumbricales muscles. 5. The four dorsal interossei muscles. 6. The three palmar interossei muscles. 7. The adductor pollicis muscle. 8. The inner head of the flexor brevis pollicis. THE RADIAL AND ULNAR ARTERIES IN THE HAND (Fig. 1 16). It now remains to reduce to its simplest terms the blood-supply of the whole hand. The ulnar artery crosses the anterior annular ligament. Below the pisiform bone it divides into (i) the superficial arch and (2) the deep ulnar branch. The superficial arch crosses the palm, resting on the flexor tendons under cover of the palmar fascia, and terminating by anastomosis in the superficial volar branch ot the radial artery. From the arch are given off the first, second, third, and fourth palmar digital branches that supply the second, third, fourth, and fifth fingers with blood. (Fig. 116.) The radial artery passes to the back of the hand, under the three extensor muscles of the thumb ; passes between the two heads of the first dorsal interos- seous muscle ; crosses the palm beneath the flexor tendons, and terminates, by anastomosis, in the deep ulnar artery. From this arch are given off five palmar interosseous arteries. Three of these the three inner go to the clefts of the fingers, where they unite with the palmar digital brandies from the superficial palmar arch. The two outermost branches go to the thumb and index finger under the special names of prince ps pollicis and radialis indicis. (Fig. 1 16.) Carpal arteries are four in number: two from the radial artery the anterior and posterior radial carpal ; two from the ulnar the anterior and posterior ulnar carpal. The anterior and posterior perforating arteries communicate, through the hand, with the dorsal interosseous arteries. These are arteries from an arch formed on the back of the carpus by anastomosis between the radial and ulnar posterior carpals. Where would yon look for tJic cephalic vein in the vicinity of the shoulder? Between the deltoid and pectoralis major muscles ; the vein is in a groo\ with a small artery the descending branch of the acromio-thoracic arter (Fig. 105.) How and where do the superficial, radial, median, and nlnar veins terminati They terminate opposite the elbow by changing their names. The radial above the elbow is called the cephalic vein. The ulnar above the elbow is called the basilic vein. The median breaks up near the elbow into the median basilic and cephalic. What are the vend' coinites / The two companion veins attending deep arteries in the extremities of body, below the knee and below the elbow. Hcnv do the superficial veins communicate with the vctne comites / By perforations in the deep fascia. H\ these communicating veins the circ ation internal to or below the deep fascia is equali/ed to the circulation cxtci to the deep fascia. If yon were going to draw blood from a patient's arm, wliy would yon select the median cephalic vein in preference to the median basilic vein for venesection / SHOULDER, ARM, FOREARM, AND HAND. 167 The median basilic vein lies on the brachial artery, which latter would be endangered were this vein selected. Suppose you employ the median basilic vein in venesection, and accidentally cut the brachial artery, and your patient dies from hemorrhage: In this case w mat ground for action for damages would relatives of deceased liavc that you could not possibly circumvent ? The ground of want of ordinary care. The cephalic vein would have answered the venesection purpose, and its employment would not have endan- gered your patient's life. Under the law, a physician must possess ordinary skill and exercise ordinary care. Can you say anything regarding any cutaneous nerves liable to be injured in phlebotomy of the median cephalic and median basilic veins f The internal cutaneous nerve crosses the median basilic vein ; the musculo- cutaneous nerve terminal crosses the median cephalic either may be injured. Name the great nerve-trunks that supply the skin of the hand with sensation. The median gives palmar and digital branches to 3.5 fingers, radial side. The ulnar gives palmar and digital branches to 1.5 fingers, front and back. The musculo-spiral, radial nerve, supplies 3.5 fingers dorsally. Have the median, ulnar, and musculo-spiral nerves any articular distribution in the joints of the hand ? Yes ; they supply joints between the phalanges the metacarpo-phalangeal, the carpo-metacarpal, the intermetacarpal, the medio-carpal, and the radio-carpal. Is there any systematic distribution of articular nen>es f Yes ; a nerve-trunk that supplies a muscle that moves a joint supplies the joint as well. The inferior radio-ulnar joint is pronated by the pronator quad- ratus, and supinated by the supinator longus. To determine the nerve-supply to this joint, you ascertain the nerve-supply to the muscles that move the joint. In this particular case the median and musculo-spiral nerve-trunks supply the pronator quadratus and supinator longus muscles respectively ; these same nerves supply the joint. Give attachments of the anterior annular ligament and tell ivhat structures pass under the same. This ligament is a specialized part of the deep fascia. It is attached exter- nally to the scaphoid bone and os trapezium ; internally to the pisiform bone and the unciform process of the unciform bone. Under this ligament pass the median nerve, with its median artery, the flexor longus pollicis, the flexor prp- fundus digitorum, and the flexor sublimis digitorum. Name, locate, and give importance of three surgical areas of the fingers. (i) The central, in which are found the tendons of the flexors in their synovial sheath, called theca. (2) On each side of this tendinous area is a neuro- vasal area, in which are found the digital arteries and nerves that supply the fingers with blood and sensation respectively. Why is infection of the little finger or thumb more dangerous than infection of the fingers between these two extremes. The vaginal thecal sheaths of synovial membrane of these extremes are in communication with the great palmar bursae under the anterior annular ligament. Give the symptoms in paralysis of the ulnar nerve. There would be loss of sensation and motion in those parts to which this nerve is distributed, as follows : (i) Loss of sensation in the skin of the little finger and the ulnar half of the ring finger and in the corresponding articulations ; (2) loss of motion in the flexor carpi ulnaris and in half of the flexor profundus digitorum muscles ; (3) loss of motion in all the interossei muscles and in the two lumbricals on the ulnar side of the hand ; (4) loss of motion in the flexor brevis minimi digiti, in the abductor minimi digiti, and in the opponens minimi digiti ; 1 68 PRACTICAL ANATOMY. (5) loss of motion in the adductor pollicis and in the ulnar head of the flexor brevis pollicis ; (6) loss of sensation in all the intermetacarpal joints. Give symptoms in paralysis of the median nerve. (i) Loss of sensation in the thumb, index, middle, and half the ring finger, on the palmar surface, and about the roots of the nails of the dorsal surface ; (2) loss of motion in all the muscles of the anterior part of the forearm, except the muscle and a half supplied by the ulnar nerve, as previously explained ; (3) loss of motion in the two lumbrical muscles on the radial side of the hand, and loss of motion in the outer head of the flexor brevis pollicis, in the opponens pollicis, in the abductor pollicis. Describe the blood-supply of the hand. The ulnar and radial arteries terminate in the superficial and deep palmar arches respectively. These arches give off branches to the hand and fingers. (Fig. 1 1 6.) Describe the superficial palmar arch. This arch is a continuation of the ulnar artery across the hand. It anasto- moses with the superficialis volae a branch of the radial artery to complete the arch. The arch may be completed by anastomosis with the radialis indicis or princeps pollicis, both branches of the radial artery also. The superficial arch gives off four branches called first, second, third, and fourth palmar digital branches when enumerated toward the thumb. The first palmar digital artery supplies the ulnar side of the little finger ; each of the three others divides into two collateral digital branches. The radial side of the index finger is supplied by the radialis indicis ; the thumb by the princeps pollicis. The digital branches from the superficial arch are joined, opposite the clefts of the fingers, by (i) the palmar interosseous, branches of the deep palmar arch ; (2) by the inferior perforating arteries from the dorsum of the hand. Describe the deep palmar arch. This arch is a continuation of the radial artery across the hand. It anasto- moses with the deep branch of the ulnar artery. (Fig. 116.) It begins at the first interosseous space, and rests on the metacarpal bones close to their carpal ends. The arch is attended by the deep branch of the ulnar nerve as described on page 164. The deep arch gives off three palmar interosseous arteries, which inosculate with the digital branches of the superficial arch at the clefts of the fingers. All the digital branches are attended by collateral nerve branches of the median and ulnar nerves. THE FOREARM. In this region you must review the osteology of the radius and ulna, and become familiar with eminences, depressions, that are associated with the origin, insertion, and location of muscles. You must be able to name all the articular surfaces, and give the rule of occupancy for their nmes. You must name tech- nically all articulations, and give the rule for writing compound words. The Radius (Fig. 124). Name tlic important points on t/iis bone concerned in practical anatomy. The radial head and its concave and convex articular surfaces. The bicipital tuberosity for the tendon of the biceps and for a bursa. The ulnar articular surface for the lesser sigmoid cavity of the ulna. The humeral articular surface for articulation with the capitellum. SHOULDER, ARM, FOREARM, AND HAND. 169 The neck of the radius located above the bicipital tuberosity. The oblique line of the radius a very important structure. The styloid process, with base and apex for ligament and muscle. The sigmoid cavity, for articulation with the head of the ulna. The semilunar and scaphoid articular surfaces. The nutrient foramen, directed upward according to rule. The interosseous border, for the interosseous membrane. The anterior surface, occupied by deep flexor muscles. The posterior surface, occupied by deep extensor muscles. The outer surface, occupied by muscles. Describe tlie anterior surface of the radius. The oblique line of the radius extends from the bicipital tuberosity to the insertion of the pronator radii teres on the outer border of the bone. (Fig. 124.) This line may be viewed as consisting of three lips : (i) An upper one, into which the supinator brevis is inserted ; (2) a middle one, from which the radial head of the flexor sublimis digitorum muscle takes its origin ; (3) an inferior one, from which the flexor longus pollicis takes its origin. This surface gives origin below the oblique line to the flexor longus pollicis and insertion to the pronator quadratus. Wliat can you say of the external surface of tJie radius ? Its upper one-half is occupied by the supinator brevis and pronator radii teres ; its lower one-half is overlapped by the radial extensors of the carpus, and crossed by the extensor ossis metacarpi pollicis and extensor brevis pollicis ; this latter muscle is also called extensor primi internodii pollicis. What can you say of the posterior surface of the radius f Its upper one-third gives origin to the radial part of the extensor ossis meta- carpi pollicis and the extensor primi internodii pollicis ; the part of the bone below this is covered by the tendons of the two preceding muscles. The Ulna. (Fig. 124.) Name the important bony parts of the ulna and give their importance in prac- tical anatomy. The olecranon process, for the insertion of the triceps muscle. The coronoid process, for the insertion of brachialis anticus muscle. The greater sigmoid fossa, for articulation with the humerus. The lesser sigmoid fossa, for articulation with the radius. The oblique line, for attachment of the supinator brevis muscle. The interosseous ridge, for attachment of the interosseous membrane. The styloid process (apex), for internal lateral ligament of wrist. The head articulates with the ulnar sigmoid cavity of the radius. The base of the styloid process, for the insertion of the supinator longus. The anterior surface of the ulna is for muscular origin. The inner surface of the ulna is for muscular origin. The posterior surface of the ulna is for muscular origin. Explain the anterior surface of the ulna. It has the nutrient foramen, which, according to the rule, is directed toward the elbow. It gives origin to the flexor profundus digitorum and pronator quadratus muscles. This surface is limited by the anterior border, the interos- seous border, and an oblique line. What can you say of the internal surface of the ulna ? It is occupied by the flexor profundus digitorum in its upper three-fourths ; the remainder of this surface of the ulna is subcutaneous. What can be said of the posterior surface of the ulna ? This is the most difficult part of the bone, but must be mastered before you can appreciate the attachment of certain muscles. This surface is subdivided by 170 PRACTICAL ANATOMY. two lines, an oblique and a vertical one, into three smaller surfaces. Above the oblique line, which runs from the lesser sigmoid cavity to the posterior border of the bone, is the anconeus muscle. To the oblique line the supinator brevis muscle is attached. The surface below the oblique line is divided by a vertical line into an internal and an external portion. What can you say of the portion of the posterior surface of the ulna internal to the vertical line ? It gives origin to the extensor carpi ulnaris muscle. What can you say of the portion of the posterior surface of the ulna external to the vertical line ? It gives attachment to the supinator brevis, the extensor ossis metacarpi pol- licis, the extensor longus pollicis, and the extensor indicis muscles. Does t/ie head of the ulna enter into the formation of the wrist-joint f No ; the triangular fibro-cartilage intervenes. The head of the ulna articu- lates with the sigmoid fossa in the lower end of the radius, forming the inferior radio-ulnar articulation. The Humerus. (Fig. 129.) Locate, classify, and describe geometrically the humerus. It is the arm bone, located between the shoulder and elbow, and long by clas- sification. It has an outer, an inner, and a posterior surface. It has an anterior, an external, and an internal border. It has a superior extremity or upper one- third ; an inferior extremity or lower one-third ; a middle one-third. Name the bony parts of the Jnimerus concerned in practical anatomy, and give their practical importance. The head of the humerus articulates with the head of the scapula. The anatomical neck gives attachment to the capsule. The surgical neck is very often the seat of fracture. The bicipital groove lodges the long head of biceps muscle. The bicipital lips surmount and deepen the bicipital groove. The greater tuberosity gives tendinous insertion to three muscles. The lesser tuberosity gives tendinous insertion to one muscle. The internal condyle is developed by traction of flexors and pronators. The internal condylar ridge has the internal intermuscular septum. The external condyle is developed by extensors and supinators. The external condylar ridge has the external intermuscular septum. The capitellum articulates with the concave surface of the radius. The trochlea articulates with the greater sigmoid of the ulna. The coronoid fossa is produced mechanically by the coronoid process. The olecranon fossa is produced mechanically by the olecranon process. The radial depression is produced by the head of the radius. Name the muscles inserted into the greater tuberosity of the liumerus. The supraspinatus into the upper facet ; the infraspinatus into the middle facet ; the teres minor into the lower facet. HOT.V is the lesser tuberosity occupied f By the tendinous insertion of the subscapularis muscle. It has one facet only. Where is the transverse hum era/ ligament and what is its function f It extends from the greater to the lesser tuberosity of the humerus, convert- ing the bicipital groove into a canal for the lodgment of the long or scapular head of the biceps muscle. Hoiv would you locate the surgical neck of the humerus f It is the constricted portion of the bone below the tuberosities. It is the portion of the humerus most frequently fractured in the upper one-third. H&iv do the three fossa of the liumerus, in the vicinity of the elbow enhance the gravity of a fracture passing through them f SHOULDER, ARM, FOREARM, AND HAND. 171 They may become filled with provisional callus and bone, when a stiff joint will be the result. Hoiv is the posterior surface of the humcrus occupied / By the long humeral head of the triceps above the musculo-spiral groove ; by the short humeral head below the groove ; by the musculo-spiral groove, in which are the musculo-spiral nerve and superior profunda artery. How is the outer lip of the bicipital groove occupied ? By the tendinous insertion of the pectoralis major muscle. How are the outer and inner surfaces of tlic Juuneriis occupied ? They are occupied by the pectoralis major, deltoid, and brachialis anticu on the outer ; the teres major, latissimus dorsi, coraco-brachialis, and brachialis anticus on the inner surface. How is the external condylar ridge occupied ? By the supinator longus and the extensor carpi radialis longior ; the former occupies the upper two-thirds, the latter the lower one-third of the ridge. Name all the muscles attached to the middle one-third of the Jiuinerus wliose action would tend to displace the fragments in case of fracture in this locality. The long and short humeral heads of the triceps, the deltoid, the coraco- brachialis, the brachialis anticus muscles. What might be the most serious complication of 'a fracture in the middle one- tJiird of the liumerus? Compression and paralysis of the musculo-spiral nerve, in which there would be inability to extend the carpus and digits and to supinate the radius. What is the direction taken by the nutrient foramen of the humcrus ? It conforms to the rule governing the direction of these foramina in the long bones of the extremities : to the elbow and from the knee being the rule. Hoiv many muscles and ligaments are attached to the humerus ? There are twenty-five muscles and eight ligaments attached. In this region you will find the following arrangement of Muscles Physiologically Grouped. Carpal Flexors. Flexor carpi radialis. Flexor carpi ulnaris. Palmaris longus. Digital Flexors. Flexor sublimis digitorum. Flexor profundus digitorum. Flexor longus pollicis. Radial Pronators. Pronator radii teres. Pronator radii quadratus. Forearm Flexors. Flexor biceps cubiti. Flexor cubiti brachialis anticus. Flexor brachio-radialis. Nerves. Median nerve and its branches. Ulnar nerve and its branches. Musculo-cutaneous nerve and its branches. Arteries and Veins. Radial artery and the deep palmar arch. Ulnar artery and the superficial palmar arch. Common interosseous artery and vein. Anterior interosseous artery and vein. Posterior interosseous artery and vein. Surgical Areas. The cubital fossa and its contents. The radial groove and its contents. The ulnar groove and its contents. 172 PRACTICAL ANATOMY. The cubital fossa has geometrically a 1. Roof, formed by the skin and fasciae superficial and deep. 2. Floor, formed by the brachialis anticus and supinator brevis. 3. Superior border, formed by an imaginary line from condyle to condyle. 4. Outer border, formed by the brachio-radialis muscle. 5. Inner border farmed the pronator radii teres muscle. Inferior profunda artery A iiastoiiio/icft magna artery Braehiul artery Radial recurrent artery . Supinator longus Radial artery. Flexor longus pollicis muscle Brachialia anticus muscle Aiili-rior nhiiir rri'iirrenl ' Posterior ulnar recurrent -Ulnar artery Anterior interosseous artery Flexor carpi ulnaris Flexor profundus digitorum muscle Anterior interosseous artery Anterior annular ligament, out - Anterior branch of ulnar artery, cut Deep pal mar arch Palmar interosseous arteries Palmar digital artery, oil short Collateral branch of palmar digital artery J FIG. 117. TIIK AKTKRIKS OK Tin; FoRKAR] ii MIK DKKI- P.M. MAR ARCH. The fossa contains the following structures (i) The brachial artery and veins ; (2) the radial artery ; (3) the ulnar artery ; (4) the tendon of the biceps muscle ; (5) the median nerve ; (6) the musculo- spiral nerve ; (7) the radial recurrent artery ; (8) the ulnar recurrent artery (9) the common interosseous artery. The radial groove has these geometrical parts : SHOULDER, ARM, FOREARM, AND HAND. 173 1. Roof, formed by skin and fasciae superficial and deep. 2. Floor, formed by flexor longus pollicis and pronator quadratus. 3. Outer border, formed by supinator longus or brachio-radialis muscle. 4. Inner border, formed by the flexor carpi radialis and pronator radii teres. 5. Contents, consisting of the radial artery and its venae comites. The ulnar groove has these geometrical parts : 1 . Roof, formed by the skin and fasciae, superficial and deep. 2. Floor, formed by the flexor profundus digitorum muscle. MEDIAN NERVE Posterior branch of anastomotica magna BRANCHES OF ( INTERNAL CUTA-J. NEOUS NERVE (_ Posterior ulnar vein Brachialis anticus Anterior branch of anastomotica magna Anterior ulnar ruin Median basilic vein MUSCULAR BRANCH OF MEDIAN NER VE Tendon of biceps Bieipital fascia Erachialis anticus Deep median vein Ulnar artery Pronator teres Radial artery Biceps Internal vena comes of brachial artery Basilic vein Brachialis anticus Cephalic vein Brachial artery EXTERNAL CUTANEOUS NER VE Musculo-spiral n. and ascending branch of radial recurrent artery Radial vein Median cephalic vein Ascending br. of radial recurrent RADIAL NERVE Radial recurrent artery Supinator ' longus Descending br. of radial recurrent Median vein RADIAL NERVE FIG. 118. THE BEND OF THE EI.HUW WITH THE SUPERFICIAL VEINS. (From a dissection by Dr. Alder Smith in the Museum of St. Bartholomew's Hospital.) 3. Outer border, formed by the flexor sublimis digitorum muscle. 4. Inner border, formed by the flexor carpi ulnaris muscle. 5. Contents, which are : ulnar artery, vena? comites, and ulnar nerve. Dissection (Fig. 117). The Radial Artery. Cut through the roof of the groove. Then, with your scissors and forceps or director, follow the artery up to the bifurcation of tlic brachial artery. Observe the numerous small muscular branches that are given off by this artery both to muscles and skin. The Ulnar Artery. Cut through the roof of its groove and follow it up as far as you can without cutting into the flexor sublimis digitorum muscle. Note 174 PRACTICAL ANATOMY. the presence of the ulnar nerve on its inner or ulnar side. Find also where this nerve gives off its dorsal ulnar cutaneous branch, to be distributed to the dorsum of the little finger and half of the ring finger. The Cubital Fossa. Figure 1 18 shows the superficial dissection of this area you have already made. Now cut the bicipital fascia with scissors, and develop the brachial artery and its branches, and make your dissection look like figure 1 19. Note (i) the brachial artery ; (2) to the inner side of this artery the median nerve; (3) to the outer side of the artery the tendon of the biceps muscle; (4) to the outer side of the tendon of the biceps, see the musculo-spiral nerve, deeply located between the brachialis anticus muscle and the supinator longus muscle, dividing into the radial and posterior interosseous nerves. Find also POSTERIOR BRANCH OF INTERNAL CUTANEO US NER VE ANTERIOR BRANCH OF INTERNAL CUTANEOUS NERVE Brachial artery BRANCH TO PRONATOR TERES Bicipital fascia, cut Pronator radii tercs muscle MEDIAN NERVE Ulnar artery Biceps muscle BRANCH OF MUSCULO- SPIRA L NER VE TO SUPINA TOR LONG US RADIAL NERVE Radial recurrent artery ,i>,,l POSTERIOR INTEROSSEO US NERVK Tendon of biceps MUSCUL O- CUTA NEO US NERVE ' Supinator longus muscle j Radial artery FIG. 119. THE BKACHIAI. ARTERY AT TIN I'.KND OK THE Ku;\v. the muscular branches to the pronator radii tores and supinator longus muscles, from the median and musculo-spiral nerves respectively. Carefully remove the deep fascia from the muscles and your dissection of the cubital fossa will look like figure I 20. You will now find each tendon individual;}-, as in figure 120, near the annular ligament; trace it up to the muscular mass from which it comes ; then refer to the figure for the name of the structure. Caution : As you thus in cleaning the muscles one by one remove the deep fasc ia from the muscles, do not destroy the superficial vessels and nerves divide only the connective tissue-. For convenience of dissection develop the muscles of first group (Fig. 120): I. Pronator radii tcrcs : origin, inner comlyle and coronoid process. SHOULDER, ARM, FOREARM, AND HAND. 175 2. Paliuaris longns ; origin, inner condyle by the common tendon. 3. Flexor carpi radialis ; origin, inner condyle by the common tendon. 4. Flexor carpi ulnaris; origin, inner condyle and olecranon. The flexor carpi ulnaris has two heads, with the ulnar nerve between them. This muscle also Triceps Brachialis antieus Pronator radii tares Flexor carpi radialis Palraaris longus Flexor carpi ulnaris sublimia digitorum Biceps Brachio-radialis Flexor longus pollioia FIG. 120. FRONT OF THE FOREARM: FIRST LAYER OF MUSCLES. forms one of the boundaries for the ulnar groove. Notice carefully the extensive insertion of the flexor carpi ulnaris muscle into (i) the pisiform bone, (2) the unciform bone, (3) the anterior annular ligament, (4) the base of the fifth meta- carpal bone. i 7 6 PRACTICAL ANATOMY. The flexor carpi radialis muscle (Fig. 120) is seldom properly dissected by the student to its specific insertion. Trace its tendon through two canals, and to two bones for insertion ; one canal is on the outer side of the annular ligament, the other is in the bone at the base of the thumb the OS trapezium. The muscle is inserted into the bases of the second and third metacarpals. lo FIG. 121. SUPERFICIAL MUSCLES OK PALMAR Asn-.i i i FOKKAKM. I. Lower portion of biceps. 2. Bicipital fascia. 3. Tendon of insertion into radius. 4, 4. Brachialis aniicus. 5. Internal head of triceps 6. Pronator radii teres. 7. Flexor carpi radialis. 8. Pal- maris longus. 9. Its termination in palmar ligament. 10. Flexor carpi ulnaris. II. Its attachment to pisiform hone. 12. Supinator longus. 13. Its attachment to styloid process of radius. 14, 14. Extensor carpi radialis longior. 15. Extensor carpi radialis brevior. 16. Extensor ossis metacarpi pollicis. 17. Its tendon of insertion into base of first metacarpal hone. 18. Tendon of extensor secuncli internody pollicis. 19, 19. Flexor suhlimis dighorum. 20, 2O. Tendons of this muscle. 21, 21. Their attachment to second phalanges of fingers. 22, 22. Attachment of tendons of flexor profundus digitorum to last phalanges of lingers. 23, 23. Lumhricales. 24. Abductor pollicis. 25. Its insertion into fir.^t phalanx of thumb. 26, 26. Flexor longus pollicis. 27. Flexor brevis minimi digiti. 28. Abductor minimi digiti. The palmaris longus muscle is properly a tensor of the palmar fascia. The muscle is inserted into the annular ligament and also into the palmar fascia. It is often absent. It is a decided flexor of the carpus. SHOULDER, ARM, FOREARM, AND HAND. 177 The pronator radii teres muscle must first be separated from the flexor carpi radialis, by dividing the connective tissue with scissors and forceps. Next pull the brachio-radialis outward, and expose the insertion of the pronator radii teres into the middle third of the outer surface of the radial shaft. Now trace the Biceps Triceps Muscles of first layer Brachialis anticus Flexor sublimis digitorum L~ Flexor carpi ulnaris Plexor carpi radialis Falmaris longus Brachio-radialis Extensor carpi radialis iongior Supinator brevis Brachio-radialia Flexor longus pollicis Extensor ossis metacarpi pollicis Extensor brevis pollicis FIG. 122. FRONT OF THE FOREARM: SECOND LAYER OF MUSCLES. median nerve down, and see it pass between the two heads of the pronator radii teres, to reach the under surface of the flexor sublimis digitorum. (Fig. 119.) The ulnar artery's course (Fig. 117) to reach its groove as described on page 172 ; Cut the origins at the internal condyle, of the pronator radii teres, i 7 8 PRACTICAL ANATOMY. BRACIHAL PLEXUS HEAD OF HUMERUS Fectoralis minor, turned back MUSCULO-CUTANEOUS NERVE BRANCH OF MUSCULO-CUTA- NEOUS TO MEDIAN NERVE Coraco-brachialis Brachial artery Superior profunda artery Biceps MUSCULO-CUTANEOUS NERVE BRANCH OF MUSCULO-CUTA- NEOUS NERVE TO BRACHI- ALIS ANTICUS Brachialis anticua MEDIAN NERVE Inner brachial vena comes MUSCULO-SPIRAL NERVE Radial recurrent artery Supinator longus Superficial median vein, cut short Fronator radii teres, superficial head, cut RADIAL NERVE . Radial artery Cut edge of flexor sublimis digitorum MEDIAN NERVE Flexor lougua pollioiB Subacapularis Acromio-thoracic artery Axillary / MEDIAN NERVE Subscapular artery Teres major Latissimus dorsi Long head of triceps MUSCULO-SPIRAL NERVE ) MUSCULAR BRANCH OF }- M I -SCULO-SPIRA L ) NER VE R i Inferior profunda artery Inner head of triceps ULNAR NERVE Anaslomotica magna artery Internal intermuscular septum MUSCULAR BRANCHES OF MEDIAN NERVE Pronator teres and superficial flexor muscles, turned back Anterior ulnar recurrent artery Deep head of pronator radii teres Posterior ulnar recurrent artery Superficial flexor muscles, turned back Anterior inlerosseons artery and nerve Flexor profundus digitorum ULNAR NER VE Ulnar artery Interosseous membrane with cut edge of pronator quadratus FIG. 123. THE LOWKK PART OK TIIK AXII.I.AKY, TIIK P,R.\rm.\i.. AND THK RADIAI, AND ULNAR AKTKKIKS. (From a dissection in the Hmiterian Museum.) SHOULDER, ARM, FOREARM, AND HAND. 179 the flexor carpi radialis, the palmaris longus, flexor sublimis digitorum, and turn them aside, but do not injure the nerves and vessels to the same. Find the ulnar artery, and you will see it passes behind all these three muscles. Now trace it a little further, and see it pass behind the flexor sublimis digitorum and median nerve. Here you will find it has reached the ulnar groove. Remem- Capsular ligament Internal lateral ligament Tubercle for the flexor sublimis digitorum Internal lateral ligament Brachialis auticus Pronator radii teres (lesser head) Flexor longus pollicis (accessory head) ULNA Interosseous membrane Flexor profundus digitorum Pronator quadratus Anterior radio-ulnar ligament Internal lateral ligament GREATER SIGMOIO FOSSA HEAD OF RADIUS NECK OF RADIUS Lower limit of orbicular ligament Oblique ligament BICIPITAL TUBERCLE Oblique ligament Supinator brevia Flexor sublimis digitorum OBLIQUE LINE RADIUS Prouator radii teres flexor longus pollicis Pronator quadratus Supinator longus External lateral ligament Interarticular flbro-cartilage Anterior radio-carpal ligament FIG. 124. THE LEFT ULNA AND RADIUS. (Antero-internal view.) ber the course : behind the median nerve and all the muscles originating from the inner condyle, except the flexor carpi ulnaris. The radial' s course (Fig. 117): You will find it very superficial. It begins at the bifurcation of the brachial artery in the cubital fossa. Now demonstrate the fact that this artery lies on : (i) Biceps tendon ; (2) supinator brevis ; (3) flexor sublimis digitorum ; (4) pronator radii teres ; (5) flexor longus hallucis ; (6) pronator quadratus. These structures form the floor of the radial groove. The flexor sublimis digitorum (Fig. 122) is brought into view by turning i8o PR A CTICAL ANA TO MY. the above muscles well aside. You will see the radial artery lying on its outer part ; the ulnar artery and median nerve above, passing behind the arch connect- ing the two heads of the flexor sublimis digitorum muscle. This muscle has three heads: (i) A condylar, arising from the inner condyle of the humerus ; (2) a Bleep Muscles of the first and second layers Flexor profundus digitorum Pronator quadratus Flexor carpi ulnaris Brachio-radialis Brachialis anticus Extensor carpi radialis longior Supinator brevis flexor longus pollicis Brachio-radialis Extensor ossis metasarpi pollicis Extensor brevis pollicis FIG. 125. FRONT OK TIIK FOREARM: THIRD LAYER OF MUSCLES. coronoid, from the coronoid process of the ulna ; (3) a radial head, from the oblique line of the radius. (Fig. 124.) Cut the radial origin, and turn the muscle toward the ulna, without injury to the radial artery, and see: (i) The median perve, on the under surface of the muscle; (2) the insertion of the brachialis anticus muscle into the base of the coronoid process of the ulna; (3) SHOULDER, ARM, FOREARM, AND HAND. 181 the origin of the flexor longus pollicis muscle ; (4) the origin of the flexor pro- fundus digitorum ; (5) the anterior interosseous artery and nerve on the inter- osseous membrane, but lying deeply between two muscles the flexor profundus digitorum and the flexor longus pollicis. The Median Nerve and its Branches. Take the nerve up, and you can easily trace muscular branches with the forceps to all the muscles on the front Pectoralis minor Coraco-brachialis Long head of triceps Inner head of triceps Brachialis anticua Semilunar fascia Tendons of insertion of pec- toralis major and deltoid Outer head ct triceps - Brachialis anticua Extensor carpi radialis longior Brachi o -rad i alis FIG. 126. SUPERFICIAL VIEW OK THE FRONT OK THE UPPER ARM. part of the forearm except the flexor carpi ulnaris and half of the flexor profundus digitorum muscles ; the flexor carpi ulnaris and the ulnar half of the flexor profundus digitorum muscles are supplied by the ulnar nerve. You will observe that some of the branches of this nerve are given off above the articulation. (Fig. 123.) Remember, the shape of a muscle is an index to nerve distribution. See introductory chapter. 182 PR A CTICAL ANA TO MY. The ulnar nerve (Fig. 123) you have already seen in the ulnar groove with its accompanying artery and venae comites. Now see how it gains this groove. Trace it behind the inner condyle, between the condylar and olecranon heads of the flexor carpi ulnaris muscle. Trace its branches to this muscle and to the ulnar half of the flexor profundus digitorum. ' The following muscles remain to be dissected (Fig. 125) : i. The flexor profundus digitontin, on the ulnar side. Pectoralis min Short head of bice Coraco-brachialis Long head of triceps Long head of bicer ^3 Insertion of pectoralis major Inner head of triceps Internal-intermuecular septum Brachialis anticus S&ML Outer part of brachialis anticug Insertion oi biceps FIG. 127. I)KKi' VIK\V OF run FRONT 01-- TIIK I'ITKK ARM. 2. The flexor longus po/licis, on the radial side. 3. The pronator radii quadrat us. 4. The sjtpinator radii brcris. You are expected to dissect these muscles and study critically their specific attachments to bone, and make your dissection tally with the origins as indicated on the hones in figure 124. The flexor profundus digitorum is seldom well learned, because students SHOULDER, AR.\f, FOREARM, AND HAND. 183 forget its aponeurotic origin. The muscle originates (i) from the anterior sur- face, upper two-thirds of the ulna ; (2) from the upper three-fourths of the posterior border of the ulna, with the flexor carpi ulnaris and extensor carpi ulnaris muscles. This latter is called the aponeurotic origin. Trace nerves to this muscle from the median and ulnar. FIG. 128. DEEP MUSCLES OF PALMAR ASPECT OF FOREARM. Lower portion of triceps. 2, 2. Attachments of pronator radii teres. 3. Attachment of flexor carpi radialis, palmaris longus, and flexor sublimis digitorum. 3' '. Tendon of biceps. 3" '. Tendon of brachialis anticus. 4, 4. Flexor carpi ulnaris. 5. Supinator longus. 6. Its distal attachment. 7. Supinator brevis. 7'. Extensor carpi radialis longior. 8, 8. Extensor ossis metacarpi pollicis. 9. Flexor profundus digitorum. 10. Its four tendons. II. Tendon for index finger. 12, 12. Tendon for middle finger. 13. Tendon of flexor sublimis. 14. Tendon of flexor profundus for little finger. 15, 15. Lumbricales. 16, 16. Attachments of abductor brevis. 17. Opponens pollicis. 18. Flexor brevis pollicis. 19. Adductor pollicis. 20. Flexor longus pollicis. 21. Its tendon. 22, 22. Attachments of flexor brevis and adductor minimi digiti. 23. Opponens minimi digiti. Detach the extreme upper origin of this muscle and study (i) the insertion of the brachialis anticus ; (2) the lesser or coronoid head of the pronator radii teres ; (3) the accessory head of the flexor longus pollicis ; (4) the coronoid origin of the flexor sublimis digitorum. 1 84 PRACTICAL ANATOMY. The Pronator Quadratus. Observe the anterior interosseous nerve termin- ating in this muscle. Detach the muscle from its ulnar origin, turn the same aside, and see the anterior interosseous artery piercing the membrane and gaining the posterior surface ; also see the anastomosis between a branch of this artery and the anterior carpals. HEAD LESSER TUBEROSITY Subscapularis Capsular ligament Coraco-brachialis brevis (Rotator burner!) BICIPITAL GROOVE GREATER TUBEROSITY Transverse humeral ligament Fourth head of biceps Coraoo-brachialis Third head of bicepe Braehialis anticus Coraco-brachialis SUPRACONDYLOID PROCESS Pronator radii teres Capsular ligament CORONUID FOSSA INTERNAL CONDYLE Internal lateral ligament TROCHLEA ROUGH SURFACE FOR deltoid THE EXTERNAL CONDYLAR RIDGE RADIAL DEPRESSION EXTERNAL CONDYLE CAPITELLUM FIG. 129. THK LEFT HU.MKKI s \\nii A SITK \OI\I>YI,. Interior Thoracic Angle. Subscapular artery and Bell's nerve. 7. External or Humeral Angle. Axillary artery and nerves. SHOULDER, ARM, FOREARM, AND HAND. 189 8. Contents. Axillary connective tissue and glands ; the axillary artery and vein and their branches ; the large branches of the brachial plexus. 9. The posterior boundary is formed by the subscapular, teres major, and latis- simus dorsi muscles. The cephalic vein and descending branch of the acromio-thoracic artery. The vein (Fig. 105) is the guide to the groove. The groove is the boundary- line between the clavicular origins of the pectoralis major and deltoid muscles. The vein opens into the subclavian. The Pectoralis Major Muscle. Remove the skin and find in the super- ficial fascia two cutaneous nerves the supraclavicular and suprasternal ; the one supplying the skin over the deltoid is the supraacromial. These are the descending branches from the superficial part of the cervical plexus. Subclavius muscle First Rib CUT END OF CLAVICLE Costo-coracoid ligament Cephalic rein . I rroin io-thoraeic artery Xti/H-riii 1 ' flinnii-ic ai-ten/ Clavi-pectoral fascia l>n*TI-:RIOR THOR- ACIC .VAY.M7-; FIG. 132. THE CLAVI-PECTORAL FASCIA. The deltoid aponeurosis is the deep fascia covering the muscle of the same name. It is continuous with the pectoral in front, the infraspinous behind, and the axillary below. The Deltoid Muscle. Detach this muscle from the clavicle (Fig. 131) and acromion process of the scapula. Turn the muscle outward. Follow the muscle to its insertion into the deltoid ridge, on the outer surface of the humenis. (Fig. 127.) Cut this insertion and turn the muscle farther back, so as to expose the insertion of the pectoralis major. The Pectoralis Major. Remove the fascia with a sharp scalpel. Place the arm at a right angle to the body ; notice that the deep fascia you are now 190 PR A CTICAL ANA TOMY. removing is continuous with the deep fascia covering the base of the axilla. Observe the sternal and clavicular origins of the muscle. See some cutaneous nerves and arteries piercing the thoracic wall, near the sternum. (Fig. 132.) The arteries are the perforating branches from the internal mammary ; the nerves are. the anterior cutaneous branches of the intercostals. Cut the insertion of the pec- toralis major. Note that the fibres that form the lower margin of the tendon of the muscle are inserted high ; those that form the upper border of the muscle are inserted low, into the posterior lip of the bicipital groove of the humerus. Now cut the clavicular origin of the pectoralis major, and carefully pull the muscle forward. On the under surface you will see the external anterior thoracic nerve, a branch of the outer cord of the brachial plexus, coming through the pectoralis minor muscle to supply the major pectoral muscle. Now cut the sternal origin of the pectoralis major and turn the same out of the way without injuring the nerve -supply. above / ^ shove r 7 f&Jai/ / Aeti Mylo-hy Old fascii Digastric fascia "~^ Submaxillary fascia ~~~ Stylo-mandibular ligament Masseteric fascia Parotid fascia CUT END OF CLAVICLE Subclavius sheath Costo-eoracoid ligament Clavi-pectoral fascia Minor pectoral sheath - Axillary or suspensory fascia FIG. 133. To SHOW SCHEMATICALLY THE DISTRIBUTION OF THE DEEP CERVICAL FASCIA AI;U\I. AND BELOW THE CLAVICLE. Four very important structures, easily understood, quickly developed, and seldom appreciated by the student, are now before you : 1. The subclarius muscle and its sheath of cervical fascia. 2. The costo-coracoid ligament, a part of subclavius sheath. 3. The clavi- pectoral fascia triangular and thin. 4. The pectoralis minor muscle and its sheath. The third layer of deep cervical fascia passes behind the clavicle, forms a sheath for the subclavius muscle, and unites along the lower margin of the sub- clavius muscle to form a thick, strong band* the costo-coracoid ligament. The fascia then bridges the triangular space between the subclavius muscle and the pectoralis muscle, under the name of clavipectoral fascia. (Fig. 132.) At this point the fascia again delatninates, to form a sheath for the pectoralis minor muscle. At the lower border of this muscle the fascia is continuous with the deep fascia of the base of the axilla, and is known technically as the axillary SHOULDER, ARM, FOREARM, AND HAND. 191 fascia. Let figure 133 illustrate in this connection schematically the distribution of the four layers of deep cervical, both below and above. It will be seen from figure 133 that the first layer of deep cervical fascia is specialized above the clavicle as parotid fascia, masseteric fascia, stylo-mandibular ligament, submaxillary fascia, digastric fascia, and mylo-hyoid fascia ; below, the first layer is attached to the clavicle. The second layer is attached above to the hyoid bone, having ensheathed the depressor muscles of this bone (Fig. 24) ; below, this fascia is attached to the clavicle. The fourth layer is connected to the occipital bone and the muscles in front of the vertebral column. The third layer is of greatest importance surgically, and the most complex. Passing behind the clavicle and sternum, this layer divides into a thoracic por- tion, which expands to form the fibrous part of the pericardium, and also into an axillary portion, which has been previously described. Pus formed between the first and second layers of deep cervical fascia would be arrested at the clavicle. Pus formed in the carotid sheath might easily find its way to either the axilla or pericardium. The student must take schematic representations with a grain of allowance, remembering that fascial development, like muscular development, is a variable thing, and in some cases would not direct pus whither the scheme might indicate. After all, the scheme just POSTERIOR Oblique line for Capsular trapezoid Tuberosity for ligament ligament conoid ligament Rhomboid ligament and Sterno- hyoid Sterno-thyroid FACET FOR FIRST COSTAL CARTILAGE STERNAL FACET ACROM1AL FACET Pectoralis major ANTERIOR FIG. 134. THE LEFT CLAVICLE. (Inferior surface.) given is to teach that many fascial entities are definitionally only a certain seg- ment of deep cervical fascia. For example : What is the subclavius sheath ? It is that part of the third layer of the deep cervical fascia that invests the sub- clavius muscle. What is the parotid fascia ? It is that part of the first layer of deep cervical fascia which is continued above the angle of the jaw to form a capsule for the parotid gland. See in the introductory chapter the rule for naming specialized modifications of deep fascia in any region of the body. The subclavius muscle arises from the first rib, near the sternum, and is in- serted into the groove on the under surface of the clavicle (Fig. 134), occupying the middle two-fourths of the surface. It is surrounded by a sheath the sub- clavian sheath. The pectoralis minor muscle arises, as a rule, from the third, fourth, and fifth true ribs, and is inserted into the anterior border of the coracoid process of the scapula. Its nerve is the internal anterior thoracic, a branch of the inner cord of the brachial plexus. The clavi-pectoral space is the triangular interval you see between the upper border of 'the pectoralis minor muscle and the subclavian muscle. As you will see on your cadaver, this space is filled in by a delicate fascia, attached above to the subclavius muscle and below to the pectoralis minor muscle. This is the clavi-pectoral fascia. (Fig. 132.) 192 PRACTICAL ANATOMY. THE AXILLA, OR AXILLARY SPACE. The axilla, or axillary space, is of interest anatomically because important surgical operations are performed here. Armpit and axilla are not synonymous terms. The physician places a clinical thermometer in the armpit not in the axilla. The axillary lymphatic glands become secondarily enlarged in cases of infection, and may require extirpation. The head of the humerus may become dislocated into the axilla and require reduction. Pus may form in the neck and find its way to the axilla and make its liberation incumbent. A wound of the axillary artery makes its ligation a necessity. Amputation at the shoulder-joint is sometimes done. The apex of the axilla or inlet has bony boundaries: (i) The outer surface of the first rib ; (2) the clavicle ; (3) the superior costa or superior border of the scapula. It is by the apex that this space communicates with the thorax and neck. Upper part of serratus magnuc Middle part Lower part FIG. 135. SERRATUS MAGNUS. THE INNER \\AI.I OF THE AXII.I.A. The base of the axilla is formed by the skin, the superficial and the deep fascia. The deep fascia in this locality is known specifically as axillary fascia ; it is also called suspensory fascia. The deep fascia is a derivative of the third layer of the deep cervical fascia, passing under the clavicle. In front it is con- tinuous with the pectoral fascia; behind, with the fascia covering the latissimus dorsi muscle. The anterior boundary is formed by the skin, fascia:, pectorales major and minor muscles, and clavi-pectoral fascia. This boundary is very well defined. The posterior boundary is formed by the subscapularis, the teres major, and latissimus dorsi muscles. SHOULDER, ARM, FOREARM, AND HAND. 193 The inner boundary is formed by six or eight ribs, their intercostal muscles and fasciae, and six serrations of the serratus magnus muscle. (Fig. 132.) The angles are three in number, and the surgical importance of each is that in these angles are found some structure or structures to be avoided, or reached in surgical operations, (i) The anterior thoracic angle contains the long thoracic artery ; (2) the posterior thoracic angle contains the subscapular artery and the external phrenic nerve ; (3) the outer or Innncral angle contains the axillary artery and nearly all the important branches of the brachial plexus. The Axillary Contents. On removing the anterior wall of the axilla, as you may now complete doing, by cutting the pectoralis minor at its insertion, and turning the same back, with its attached clavi-pectoral fascia, you will see (i) a mass of axillary connective tissue containing some fat and blood-vessels, the alar thoracic vessels, and axillary lymphatic glands. In health these glands are not larger than a small pea, and are bluish in color. When diseased, as is frequently the case in dissecting-room material, they are often very large ; they may be as CLAVICLE CORACOIO PROCESS Supra-spinatus Subscapularis Teres major Latissimus dorsi Coraco-brachialis and short head of biceps Pectoralis major FIG. 136. FRONT VIEW OF THE SCAPULAR MUSCLES. THE POSTERIOR WALL OF THE AXILLA. large as a hazelnut, or even larger. Each student should visit every table in the room, when this area is being dissected, to inspect the condition of these glands. To clean out the axilla means, in surgery, to remove the diseased axillary glands. This operation is attended by slight hemorrhage. The vessels that should bleed are the alar thoracics. These supply the glands and fat in this space. The term unavoidable hemorrhage would be an excellent expression by which to designate the bleeding incident to the removal of these glands, if this expression were not already the stereotyped property of obstetric nomenclature. Systematic Examination of the Walls and Contents of the Axillary Space. i. Examine the inner icall and find: (i) The outer surface of the six upper ribs. (2) The serrations of the serratus magnus muscle. (Fig. 135.) (3) Coming through two or three intercostal spaces, the second, third, fourth, some cuta- neous nerves will be seen. These nerves cross the space and seem to become lost in the mass of fat you have just examined. These nerves are the posterior lateral 'cutaneous branches of the intercostal nerves. Now trace them out as follows : One passes out under the pectoralis major muscle to the skin of this muscle, in front ; a second passes out behind, around the latissimus clorsi, to the skin of this muscle ; a third passes down the center of the space, joins a branch of the i 9 4 PR A CTICAL ANA TOM Y. BRACHIAL PLEXUS HEAD OF HUMERUS Fectoralis minor, turned back MUSCULO-CUTANEOUS NERVE BRANCH OF MUSCULO-CUTA- NEOUS TO MEDIAN NERVE Coraco-brachialiB Brachial artery Superior profunda artery Biceps MUSCULO-CUTANEOUS NERVE URANCH OP MUSCULO-CUTA- NEOVS NERVE TO BRACHI- ALIS ANTICUS Brachialis anticus MEDIAN NERVE Inner brachial vena comes MUSCULO-SPIRAL NERVE Radial recurrent artery Supinator loiigus Superficial median vein, cut short Fronator radii feres, superficial head, cut RADIAL NERVE Radial artery Cut edge of flexor sublimis digitorura MEDIAN NER VE Flexor lougus polliois Subscapularis Acromio-lhoracic artery Axillary artery MEDIAN NERVE Subscapular artery Teres major Latissimus dorsi Long head of triceps MUSCULO-SPIRAL NERVE ) MUSCULAR BRANCH OF \ Ml'KCULO-SPIRAL Inferior profunda artery Inner head of triceps ULNAR NERVE BM Anaslomolica marjna artery Internal intermuscular septum MUSCULAR BRANCHES OF MEDIAN NERVE Pronator teres and superficial flexor muscles, turned back A n! 1 rior ulnar recurrent \ HI-' AN INTERCOSTAL NERVE <: \.\i:/,/o\ Oh' I'osTKii- IOK ROOT OF SPINAL M-:I; \-K ANTERIOR ROOT OF XPIXAL XEUVE .s ) '. V r. I Til /; Tl (' GANGLION A XI RA .MI ( 'OMM I \\/( '. I .V /'/> FIG. 141. THE INTERCOSTAL NKKVF.S. LATERAL CfTANE- or.v AN INTERCOSTAL SPACE An external intercostal * muscle An internal intercostal muscle COSTO-CHONDRAL JUNCTION Iiili'iiinl iixiiuiiHtry artery TEHMISrS 0^ IXTKR- rox r.\i. XKR\'K LYIXI; OX POSTERIOR SUR- FM'K (>/ IXTKftl'OST.I I, MI'SfLK. A\l) PASSIXH f\ FROXT OF THK f\- TK I! XA L .WA MM A R Y ARTfJ/lY Figure 140 shows the mnscnli infracostales. These muscles arise near the angle of the rib, from the inner surface and lower border ; they are inserted into the second rib above. They are also called subcostals or mnsculi subcostales. Intercostal Fascia. Remove every vestige of the pectoralis major, and expose the intercostal muscles. Find a delicate layer of fascia covering the outer surface of the external intercostal muscle. This is the external intercostal fascia. Trace this fascia to the sternum. You can now see, showing through this fascia, the internal intercostal muscle. The internal intercostal fascia covers the inner surface of the internal intercostal muscle. The middle intercostal fascia is be- tween the two intercostal muscles. The Intercostal Nerves. Figure 141 represents the cour'se and divisions and relations of an intercostal nerve, such as may be seen in the second, third, fourth, fifth, and sixth intercostal spaces. Students frequently graduate unable to locate properly an intercostal nerve. You are to note the following stages of an intercostal nerve : 1. -The nerve is formed by an anterior and a posterior root. 2. The posterior or sensory root has a ganglion. '4 PRACTICAL ANATOMY. 4. 5. 6. 3. The intercostal nerve lies between the pleura and external intercostal muscle. The nerve throws off muscular branches. The nerve throws off lateral cutaneous branches. The nerve is in the substance of the internal intercostal. 7. The nerve is on the posterior surface of the internal intercostal. 8. The nerve passes in front of the internal mammary artery. 9. The nerve throws off anterior cutaneous branches. The branches of the intercostal nerve are : (i) Muscular, to the internal and external intercostals, the infracostales, the serratus posticus superior, the triangu- laris sterni, and levatores costarum ; (2) cutaneous branches, lateral and anterior. Now you may find the nerves according to the diagram. You will find the Sterno-hyoid Stern o-thyroid Triangularia a terui Transveraalis abdominis FIG. 142. THE MUSCLES ATTACHED TO THE BACK OK THE STERNTM. intercostal arteries with the nerves to some extent. In this dissection care must be taken not to injure the pleura. \\licrc to I'ind tlic Internal Mammary Artery and I'cins. With your forceps go through the soft structures one-half of an inch to the outer margin of the sternum on either side. Try to find this artery, and ligate the same, without injuring the pleura. In reaching this artery, do you cut through the external intercostal muscle? No. Do you cut through the three intercostal fascia.- and internal intercostal muscle? Yes. Give the location of the internal mammary artery. It lies between the pleura and internal intercostal fascia. It has two companion veins. The Inner Surface of the Sternum and Ribs (Fig. 142). See : i. The internal intercostal muscles, eleven pairs on each side. 77//1 THORAX. 203 2. The origin of the stcrno-liyoid muscle. 3 . The origin of tJie sterno-tJiyroid muscle. 4. The origin and insertion of the triangnlaris stcrni. 5. The costal and sternal origins of t/te diapJiragm. 6. The parietal layer of the pleura, through which you can see the muscles. 7. The internal mammary artery and veins, on each side of the sternum, giving off their anterior intercostal and other arteries. (Fig. 143.) 8 Dissection. Cut through the ribs in the mid-axillary line. (Fig. 145.) Cut through the abdominal walls along the margin of the false ribs. Cut through PHRENIC NERVE Subclavian artery Subclavian vein, cut Anterior intercostal branch Anterior intercostal branch Mnsculo-phrenic artery Deep circumflex iliac artery - Common carotid artery Internal jugular vein Subclarian rein, cut Soaleuus anticus muscle Trianpcularis aterni muscle Perforating branch Superior epigastric artery Deep epigastric artery FIG. 143. SCHEME OF THE INTKRNAI. MAMMARY ARTERY. the diaphragm close to the ribs and sternum. Then elevate from below the section of thoracic wall you have made loose. As you turn this section up you will see a large amount of anterior mediastinal connective tissue behind the sternum. Elevate the section slowly ; let an assistant divide the connective tissue, and do not injure the numerous structures that enter or leave the apex of the thorax. Figure 141 shows the infracostales. These muscles arise near the angle of the ribs, from the inner surface and lower border ; they are inserted into the second rib above. They are also called snbcostals. 204 PRACTICAL ANATOMY. The internal mammary artery has the following branches, all of which you can easily find : 1. The perforating branches that come through the five or six upper inter- costal spaces and supply the major pectoral muscle and the mammary gland. 2. The mediastinal branches to the mediastinal connective tissue and glands under the sternum. They also supply the thymus gland in the foetus or its remains in the adult, hence they are called also tliyinic 'arteries. 3. The sternal branches, quite small and numerous, to the sternum and tri- angularis sterni muscle. 4. Pericardiac brandies to the anterior surface of the pericardium. 5. The comes nervi phrenici is a long, slender artery that accompanies the phrenic nerve to the diaphragm. You will find this nerve between the pleura and pericardium. 6. The anterior intercostals supply the six upper intercostal spaces. There are two in each space, one above and one below. They anastomose with the posterior intercostal arteries from the aorta. 7. The musculo-phrenic, that furnishes the anterior intercostal arteries to the remaining spaces. It also supplies branches to the diaphragm. 8. The superior epigastric passes through the diaphragm between its costal and sternal parts, enters the sheath of the rectus muscle, finally the muscle itself, and anastomoses with the deep epigastric branch of the external iliac artery. The internal mammary artery is a branch of the subclavian, as you saw when you dissected the neck. Its parietal branches are to the anterior walls of the thorax what the parietal branches of the aorta are to the posterior walls of the thorax. Now go down between the sixth and seventh cartilages and find where the artery divides into the musculo-phrenic and superior epigastric. The thoracic walls are supplied with blood, then, by intercostal arteries. These arteries come : (i) From the aorta ;' (2) from the internal mammary ; (3) from the subclavian ; this latter furnishing the artery to the superior intercostal space. The blood from this area is collected and delivered as follows : the first or superior intercostal vein is tributary to the vertebral vein ; the others to the azygos veins, in the posterior mediastinal space, to be presently dissected. The triangularis sterni muscle arises from the lateral aspect of th( sternum, and is inserted into the cartilages of the third, fourth, fifth, and sixtl ribs. INTERIOR OF THE THORAX. Geometrically the thorax possesses : 1. An apex, through which pass : (i) The oesophagus ; (2) the trachea ; common carotid artery on the left, and the innominate artery on the right side ; (4) the phrenic, pneumogastric, sympathetic, and recurrent laryngeal nerves ; (5) the internal jugular and subclavian veins ; (6) the thoracic duct ; (7) the sterno- hyoid and sterno-thyroid muscles ; (8) the third and fourth layers of deep cervi cal fascia form the pericardium and invest the longus colli muscle respectively ; (9) the subclavian artery on the left side. 2. A base, formed by the diaphragm. This is a niusculo-aponeurotic struc- ture, in relation with the pleurae and pericardium above and below with the peritoneum. It transmits: (i) The aorta; (2) the ascending vena cava ; (3) tin- (i-sophagus and pneumogastric nerves; (4) the superior epigastric branch of the internal mammary artery ; (5) the thoracic duct ; (6) the communicating branch from the lumbar veins to the a/ygos veins. THE TJIOK.IX. 205 3. An anterior wall, formed by the sternum and cartilages of the ribs, with their investing soft parts. On this we find the internal mammary arteries and their veins, and the sterno-hyoid, sterno-thyroid, and triangularis stern i muscles. 4. A posterior wall, formed by the thoracic portion of the vertebral column and the ribs outward from their heads to the angles, with their investing soft parts. 5. Two lateral walls, formed by the ribs and intercostal spaces, between the angles and the costo-chondral articulations. Vena cava superior Arch of aorta Pulmonary artery BRONCHUS / Pulmonary vein ENSIFORM CARTILAGE IK;. 144. ANTERIOR VIEW OK THE LUNGS: PERICARDIUM. (Modified from Bourgery.) The inlet or apex of the thorax is bounded by the sternum, first rib, and first thoracic vertebra. The diaphragm is attached to, or rather has its origin from, the sternum, ribs, hgamenta arcuata interna and externa. There are twenty- four ribs, twenty-two intercostal spaces, and forty- four intercostal muscles. The interior of the thorax consists of: 1. A pulmonary portion, a compartment containing the lungs. 2. A mcdiastinal portion, or non-lung-containing compartment. The pulmonary portion of the thoracic cavity contains the lungs. The inner 206 PR A CTICAL ANA TOM \ '. surfaces of ribs are covered by the pleura costalis. The lung is invested by pleura, just as the abdominal organs are invested by peritoneum. The layer of pleura covering the lungs is called visceral layer, or pleura pulmonalis. The pleural cavity is the space between the two layers of pleura. This cavity contains only a small amount of serum for lubrication. You will often find adhesions between the parietal and visceral layers of the pleura, the result of inflammation. Frequently you will find many ounces of fluid, the result of hypersecretion : this condition is hydro-tfiora.v. Occasionally you will find pus in the pleural cavity : this is pyo-tJwrax. You may find foetid gas : this is pneumo- tliorax; or pus and gas, pyo-pneuino-tliorax. Pectoralia major muscle Pectoralis minor muaclj SUPERIOR LOBE , Serratus magnua muscle MIDDLE LOBE SECTION OF SEVENTH RIB Diaphragm STERNUM ENSIFORM CARTILAGE FIG. 145. ANTERIOR VIKW OF THK THORAX \YITII CHKST WALL RKMOVKD, SIIO\VIM; THK LUNGS. (Modified from Bourgery.), Cavities of tubercular origin are often found in the lungs. In these case notice the cavity, while an assistant inflates the lung. A large percentage of the cases you see in the dissecting-room have pulmonary tuberculosis ; some have croupous pneumonia ; others, pulmonary gangrene. AntJiracosis is carbuncular disease of the lung. This you will find occasion- ally. Every adult lung you will see on the tables will be literally covered by carbonaceous spots. This pigmentation is undoubtedly produced by impure air ; still, you fail to find it in domestic animals at the stock-yards. Possibly if these animals lived forty years, they would show the same spots on their lung surfaces that are found in man's lungs. The apex of the lung extends one and one-half inches above the first rib. The THE THORAX. 207 base of the lung rests on the pulmonary surface of the diaphragm. The lung has a pleuritic attachment to the vertebral column, called the ligauicntum latmn pulmonis. Anatomical Root of the Lung. Like the root of the liver, the root of the lung transmits structures whereby the lung carries on (i) the functional activity ; (2) the nutritive activity of the lung. By the latter the lung as an organ lives ; by the former the lung as an organ aerates the blood. Pull the lung carefully over the cut margin of the ribs (Fig. 145) and you will see the root structures. Inflate the lungs and study the lobes and fissures. Introduce a one-half inch rubber tube into the trachea and inflate the lungs. You will then see a space, corresponding to one-third the anterior surface of the heart, that is not covered by the lungs when they are inflated. If you could mark on the chest-wall the size of this space, that would give you the area of precordial dullness on percussion. As you inflate the lungs you notice the right lung has three, the left two, lobes. The root structures of the lungs are : 1. The bronchial tubes, air-conveying conduits. 2. The bronchial arteries, nutritive conduits to the lungs. 3. The pulmonary artery, bearing blood laden with CO 2 . PLEURA PULMONIS PLEURAL CAVITY PLEURA COSTAUS FIG. 146. INVAGINATION OF PLEURA. The three structures produced by invagination of pleura may be schematically represented as the above figure shows. I. The visceral layer, or pars pleurae invaginata. 2. The parietal layer, or pars pleurse costalis. 3. The pleural cavity. The same schemejgives like results in accounting for the cavity and layers in connection with peritoneum and pericardium. 4. The pulmonary veins, bearing blood -j-O, and CO 2 . 5. The pulmonary sympathetic nerves, from the pulmonary part of the cardiac plexus. You are to learn that the thoracic, abdominal, and pelvic viscera are inner- vated' by the sympathetic nerve. ' The cardiac gangliated plexus supplies the thoracic organs ; the solar, the abdominal organs ; the Jiypogastric, the pelvic organs. Each plexus, however, has a primary element, sympathetic, and a secondary piieumogastric element ; hence we say, in general, the nerve-supply is from the sympathetic. Analytically, we speak of the nerve-supply as sympa- thetic and pneumogastric. The Pulmonary Trio. The sympathetic nerve always accompanies the artery to an organ. The artery that nourishes the lungs is the bronchial ; but this artery accompanies the bronchial tube. The pulmonary trio, then, consists of the bronchus, the bronchial artery, and the sympathetic nerve-supply. Relation of bronchus, artery, and veins on the two sides are as follows : (i) On the right side, from above down bronchus, artery, and vein. From before back vein, artery, bronchus. O the left side, from above down artery, bronchus, vein. From before back vein, artery, bronchus. 208 PRACTICAL ANATOMY. What is the relation of the visceral and parietal pleune at t/ie roof of tlic lung f They are continuous, since the pleura is an invaginated sac. (Fig. 146.) Name the three structures produced by a simple invagination of the pleura. 1. The visceral layer, or the pars pleurae invaginata pleura pulmonis. 2. The parietal layer, or the pars pleura costalis parietal pleura. 3. The space between the two layers, the pleural cavity. What are the grand divisions of the parietal pleura f The diaphragmatic, the mediastinal, the external or costal. The diaphrag- matic rest on the diaphragm ; the costal on the ribs and internal intercostal mus- cles ; the mediastinal is in relation with the contents of the mediastinum. Has the upper extremity of the pleura pulmonis any important relations / Yes ; it extends an inch above the first rib, and is in relation to the sub- clavian vessels, which lie in front and internal to the apex of the pleura. Is there any special provision made for strengthening- or protecting that part of the dome of the pleura that projects abm>e the first rib ? Yes ; there is a heavy layer of subpleural connective tissue, called Sibson's fascia, that descends from the scaleni muscles to the first rib and gives strength to the dome. HOIV is the root of each lung secured to tJie diaphragm f By a fold of pleura called the ligamentum latum pulmonis. Name the geometrical parts of the lung. The apex, base, outer surface, inner surface, posterior border, anterior border, and pulmonary root. What is the inner surface of the lung ? That part in contact with the mediastinum and pericardium ; it is concave. Where is the base of the lung and what is its shape f It is in contact with the diaphragm ; it is concave. What can you say about the anterior border of the lung ? It is sharp and thin, and separates the external from the inner border. The posterior border is thick and round, and occupies the deep groove on each side of the vertebral column. Is there any provision made for possible physiological increase of breathing- space in the pleural spaces ? Yes ; the same principle is here seen as is observed in the tortuous arteries of some localities a condition apparently foreseen to meet an emergency. The lung, under ordinary conditions of man, is less extensive than the pleural sacs. The parietal pleura is really tortuous in the region of the anterior border of the lung. The emergency that would take the kinks out of this pleura would be physical training, where wind is the prime desideratum, as in pugilistic mills. The same principle is seen in a pregnant uterus, reducing the tortuosity of uter- ine arteries. THE MEDIASTINAL SPACES. 1. Anterior Is the space between the heart and sternum. 2. Middle Is the space occupied by the heart and its root structures. 3. l\>stcrior Is the space behind the heart. The Contents of the Anterior Mediastinal Space : 1. The remains of tlic thy inns gland a fu-tal structure. 2. The left bracJno-ccplictlic or left innominate rein. 3. The internal mammary artery and its companion veins. 4. The nearly obsolete triangnlaris sterni muscle. 5. The origin of the sterno-hyoid and sterno-tltyroid muscles. 6. The large amount of connective /issue you noticed when you opened the thorax. /'///: THORAX. Contents of Middle Mediastinal Space : I. Pericardium and heart, and the cardiac root structures. Phrenic nerve and its artery ctrtcria comes ncrvi phrenici. The aorta, pulmonary artery, and pulmonary vein. The vena cavce, superior and inferior, ascending and descending. The trackeal bifurcation and the two bronchial tubes. Bronchial lymphatic glands and their vessels and nerves. The cardiac plexus of the sympathetic nerve. HYOID BONE Thyro-hyoid membrane THYROID CARTILAGE Sterno-thyroid muscle Crico-thyroid membrane Crioo-thyroid muscle THYROID GLAND Right common earotid artfrii RIGHT PNEUMO- GASTRIC NERVE Ili'ihl in/midl jii'/idnr rein Level of sternum SECTION OF CLAVICLE SECTION OF FIRST RIB SECTION OF STERNUM Thyro-hyoid muscle Lateral portion erieo- thyroid membrane Omo-hyoid muscle 7 Sterno-mastoid muscle CRICOID CARTILAGE FIRST RING OF TRACHEA TRACHEA Left suspensory ligament LEFT RECURRENT NER VJJ (Esophagus Left innominate vein LEFT LOBE OF TIIYMUS Left internal mammary artery Pericardium SECTION OF FIFTH RIB CARTILAGE ENSIFORM CARTILAGE FIG. 147. THYMUS GLAND IN A CHILD AT BIRTH. The Posterior Mediastinal Contents : 1. The aorta and posterior intercostal arteries. 2. The oesophagus and pneumogastric nerves. 3. The vena asygos and intercostal veins. 4. The thoracic duct and its fatty bed. 5 . The thoracic .gangliated sympathetic cord. 6. The greater, lesser, and smallest splanchnic nerves. 210 PRACTICAL ANATOMY. 7. The intercostal nerves, each giving off" two communicating branches ranii coinnmnicantes to the ganglia of the sympathetic nerve in the thorax. Dissection of these regions must be done with the forceps. No cutting instru- ment should be used. Proceed in this order: (i) Find the phrenic nerve, a branch of the third and fourth cervical, and the arteria comes nervi phrenici, a branch of the internal, mammary artery, on either side of the pericardium, between this structure and the pleura. This nerve comes from the third and fourth cervical plexus. It lies on the scalenus anticus muscle in the neck. It enters the mediastinal space between the subclavian artery and vein. It passes anterior to the root of the lung. It communicates with the sympathetic, with the nerve SUP* v. c FORAMEN OVALE PLAC E N T A Fu;. 148. SCIIKMU OK THE ]''/< pulmonary vein Descending aorta LEFT PLEURA Oblique vein Left coronary artery Coronary sinus Ijfft marginal branch of left coronary artery Ventricular branches of coronary artery Left ventricle RIGHT BRONCHUS Intercostal artery Bronchial artery POSTERIOR MONARY /'/,/;. \TX Hiijht jmliiiunnry in ti'ry Right pulmonary vein Vena azygos major 'RIGHT PLEURA Lfft auricle Posterior cardiac vein Posterior intrrn nt i iftihir branch of right coronary artery Fic;. 151. THK HKART AND GKKAT YKSSKI.S, \VITII TIIK ROOT 01- TIIK I.UNC.S, SKEN KK<>M 1:1 IIIND (St. Bartholomew's Hospital Museum.) mogastric nerves ; (7) the pulmonary sympathetic plexus; (8) some bronchial lymphatic glands. The Cardiac and Pulmonary Plexuses. ( )n the posterior part of the. bronchi you will find some nerves ; these form the posterior pulmonary plexus. On the front of the bronchi you will also find some nerves ; these form the anterior pulmonary plexus. Now cut through the trachea two inches above its bifurcation, and you will sec, immediately in front of the bifurcation, the deep eardiac plexus. Look under the arch of the aorta and see the superficial eardiae plexus. The above plexuses furnish nerves that supply the heart and lungs. The pulmonary plexus is a subdivision of the cardiac plexus. The terms anterior and posterior pulmonary are used for convenience in describing the particular regions THE THORAX. 215 occupied by the plexuses. The terms superficial and deep cardiac are used for the same reason. The cardiac plexus is formed as follows : 1. By cervical and thoracic branches of the pneumogastric nerve. 2. By branches from the recurrent laryngeal nerve. 3. By branches from the cervical sympathetic nerve. to G.ofRoot ofPneunwy. tofetrosal ff.o Glosso-ph, G.*GANGLION. Cardiac br.fkPneumogastnc p.= PLEXUS. andRtc.Larynyeal Kcrvts A.> ARTERY. 1.2.3.4. BRAN CHES. FROM PNEUMOGASTHIC \ f f-nr i NERVE TOTHECAROIAC \G-ofWrisberg VuhantoS-PGanglicri + r so *_ LaraeS.Petrosal iff u. offnc turwyajtric ' toffypoyloaaal Jf. tributary to the left brachio-cephalic ; the right to the vertebral vein. 'The thoracic duct lies in a bed of fatty connective tissue, between the aorta and the vena a/ygos major, on the vertebral column. It is confluent to the left brachio-cephalic vein. It originates in the receptaculum chyli, on the second lumbar vertebra. It passes through the aortic opening in the diaphragm. This is easily inflated, in the recently-dead, before the material lias been embalmed. To do this inflation, cut into the brachio-cephalic and find the orifice of the duct. The oesophagus extends from the pharynx to the stomach. It leaves the thorax |>y the o-sophagcal opening in the diaphragm. Find it passing behind (i) the arch of tin- aorta, (2) the trachea, (3) the left bronchus. (4) the left com : THE THORAX. 217 mon carotid and left subclavian veins, and (5) pericardium. Find (6) the vena azygos major to the right, and (7) the aorta to the left. On each side find (8) the pneumogastric nerves. Near the diaphragm find (9) the left pneumogastric in front, (10) the right behind the oesophagus a result of rotation of the stomach. The pneumogastric nerves (Fig. 153) have been thoroughly considered in the dissection of the neck. Still, there are some practical relations of this nerve RIGHT RECUR- RENT LARYN- GEAL NERVE Transverse cervical artery Right common carotid artery Suprascapular artery Internal jugular vein PNEUMO GA STRIC NERVE Subclavian vein Inferior thyroid vein PHRENIC NER VE Left innominate vein Ascending aorta -J-^ |r Superior vena cava RIGHT BRONCHUS Branch to superior lube of lung Upper branch of right pulmonary urti'ri/ Branch to middle lobe of lung Right pulmonary vein RIGHT AURICLE Right coronary artery Lower branch, of right pulmonary atii'ri/ THORACIC VERTEBRA Intercostal vein Intercostal artery Vena azygos major Intercostal vein Intercostal artery __ Intercostal vein Intercostal artery THYROID BODY LEFT RECURRENT LARYNGEAL NER VE PNE UMO GA S TRIC NERVE Left internal jugular vein Left common carotid artery Left subclarian artery Left subclavian vein TRACHEA Inferior thyroid vein PHRENIC NER VE (hooked aside) RECURRENT LARYNGEAL NERVE PNEUMOGASTRIC NER VE DUCTUS ARTERIOSUS Left pulmonary artery Pulmonary artery Right pulmonary artery LEFT BRONCHUS Left coronary artery Upper left pulmonary . vein RIGHT VENTRICLE (Conus arteriosiis) Lower left pulmonary artery Lvuier left pulmonary vein CESOPHAGUS (hooked aside) THORACIC DUCT Thoracic aorta, FIG. 153. THE ARCH OF THE AORTA, WITH THE PULMONARY ARTERY AND CHIEF BRANCHES OF THE AORTA. (From a dissection in St. Bartholomew's Hospital Museum.) in the thorax I wish the student to understand. The pneumogastric nerve leaves the cranium by the jugular foramen. You found it in the carotid sheath, between the internal jugular vein and common carotid artery in the neck. The two pneumogastric nerves differ in their relations somewhat, hence dissect them separately. The right nerve (Fig. 15 3) crosses the right subclavian artery, and at once gives off its recurrent or inferior laryngeal nerve, which passes upward and inward, behind the subclavian and common carotid arteries, to the larynx, 15 2i8 PRACTICAL ANATOMY. lying, in its course, between the oesophagus and trachea, in a bed of fatty connec- tive tissue. In the lower part of the neck, cervical and thoracic cardiac branches are given off to the cardiac plexus. A little lower are given off pulmonary branches, called, from their distribution, anterior and posterior ; these supply the lungs through the pulmonary gangliated plexus. CEsophageal branches from the pneumogastric form the plexus gulae. The pneumogastric nerve leaves the thorax by the oesophageal opening in the diaphragm, and sends branches to the solar plexus, from which, possibly, all the abdominal organs receive pneumogas- tric influence. This, however, is purely physiological speculation. On the left side, the pneumogastric nerve passes behind the left brachio- cephalic vein and in front of the arch of the aorta. As it is crossing the arch it gives off its recurrent laryngeal branch. This nerve passes to the outer side of the ductus arteriosus and gains the side of the left bronchus and trachea. The inferior or recurrent laryngeal nerves supply branches to the trachea, oesophagus, and to all the intrinsic muscles of the larynx except the crico-thyroid muscle. The coronary arteries supply the heart. They are given off from the ascend- ing aorta. They embrace at their origin the common pulmonary artery by their divergence. (Fig. 153.) Blood is returned from the heart by two sources : (i) By minute veins which end in the foramina of Thebesius in the right auricle of the heart. (2) Numerous veins come together to form the great coronary sinus. This sinus opens into the right auricle of the heart, between the auriculo- ventricular opening and the ascending vena cava. You will demonstrate this opening, and also the valve, called the coronary, on your dissection. The Right Auricle of the Heart. Cut through the wall of the auricle from the ascending to the descending vena cava in a direction from above downward. Now, having thoroughly washed the parts, you will see : (i) The appendix auri- cula, and (2) the atrium, sinus, or principal cavity of the auricle. In the atrium see and locate: (i) The fossa waits, surrounded by a rim called the annnlns ovalis; (3) the caval and auriculo-ventricular openings (Fig. 154); (4) the coro- nary valve or valve of Thebesius and the RustacJiian valves, -at the respective openings for the coronary sinus and ascending vena cava ; (5) the musculi pec- tinati, which you will see on cutting through the appendix auriculae. These latter are mechanical devices for giving strength to the walls of the auricle, analogous to the chordae tendineae in the ventricles. The Semilunar Valves (Fig. 154). Cut into the aorta and pulmonary artery an inch above where they leave the heart, and demonstrate these valves. Fill the vessels with water and show the action of these valves in preventing regurgitation. In the central point of each free margin of the valve find the corpus Arantius. This is a mechanical device, whereby the valves occlude more perfectly. Also find in the aorta the sinuses of Valsalva, or aortic sinuses, oppo- site to which are found the attached margins of the valves. Above the fret margin of the valves find the coronary arteries, left and right, given off from tin aorta. The auriculo-ventricular valves, right and left, guard the respective open- ings between the auricles and ventricles. Cut into the right ventricle (Fig. i 54) and study the mechanical devices known as columnar carneae and chorda ten- dineae ; also the left ventricle study in the same manner. The septa are : (i) The interauricular. In this you see the fossa ovalis. In the foetus this was a communication between the auricles, called the forumei ovale. It is in the posterior wall of the right auricle. (2) The interventricular, separating the ventricles. Steps in Adult Circulation. ( i ) Blood is taken from below the diaphragm by the inferior vena cava, and from above the diaphragm by the descending \vna cava, to the right auricle of the heart. (2) Blood flows from the right s THE THORAX. 219 auricle* through the auriculo-ventricular opening, to the right ventricle. This opening is guarded by the right auriculo-ventricular valves. (3) Blood flows from the right ventricle, by the pulmonary artery, to the lungs. This artery is guarded by the pulmonary semilunar valves. (4) Blood flows from the lungs to the left auricle of the heart by the pulmonary veins. These veins have no valves. (5) Blood passes from the left auricle, by the left auriculo-ventricular opening, Left carotid Innominate Left subclavian Right pulmonary artery Duclus arteriosus Left pulmonary artery Pulmonary artery Pulmonary semilunar valves LEFT AURICULAR APPENDIX Small papillary muscle connected with septum (1) Columna caruea CHORD/E TENDINE* Anterior papillary muscle Left coronary artery Vena cava inferior ANTERIOR SEGMENT OF TRICUSPID VALVE RIGHT SEGMENT OF TRICUSPID VALVE SECTION OF VENTRICULAR WALL Vena cava inferior . lary muscle FIG. 154. ANTERIOR VIEW OF THE RIGHT CHAMBERS OF THE HEART, WITH THE GREAT VESSELS. (3) Posterior papil- (2) Columna oarnea ile to the left ventricle. This opening is guarded by the left auriculo-ventricular valves. (6) Blood passes from the left ventricle through the aorta to all vascu- lar parts of the body. The aorta is guarded by the aortic semilunar valves. Systole is a term by which contraction of the auricles and ventricles is desig- nated ; diastole is its opposite. The one extrudes, the other draws in, blood. The Foetal Circulation. The lungs are essentially organs whose use in distributing the blood for purification begins after birth. Before the product of 220 PRACTICAL ANATOMY. conception reaches the ninth month of utero-gestation, its blood is distributed for purification in an organ called the placenta. This placenta, while structur- ally very different from the lungs, accomplishes for the blood of the foetus just Right innominate vein Vena cava superior Right pulmonary artei~y Vena cava inferior Left branch of portal vein DUCTUS VENOSUS Umbilical vein Portal vein Right bnnifh <>f portal vein Umbilical vein Umbilical arteries _ 1 Hypogaitric artery Left innominti/p vein Arch of aorta DUCTUS ARTERIOSUS Left pulmonary artery Descending aorta Superior mesenteric artery Inferior mesenteric artery Left common iliac artery I nt f rnnl i/iui- uri, Kill-null /linear/ fry ;. 155. THK HKART, WITH TIIK ARCH <>i THK AORTA, TIIK I'ILMONAKY AKTK.KY, 1111 I- Al; I I KloSUS, AND THE VESSELS CONCERNED IN TIIK Fd'.TAI. CIRCULATION. (From a preparation of a foetus in the Museum of St. Bartholomew's Hospital.) the same results as are accomplished by the lungs /vW part cm. The purification of the blood in cither case is in accordance with the law of physics regulating the diffusion of gases. Blood, on entering lung or placenta, is laden with O )._, ; THE THORAX. 221 on leaving the same it is laden with O. The difference, then, between the ante partem and post partem purification of blood is not a physiological one ; but a difference is to be found in certain anatomical routes taken by this blood, in the one case to and from the placenta, in the other case to and from the lungs. A study of the metamorphosis of parts after functional activity ceases is replete with interest, since it shows the converse of the law of physiology that growth is the correlation of function. Study the following steps in the foetal circulation, in order that in your dissection you may be able to appreciate the several fcetal vestiges you shall find there. 1. In the foetus the blood is purified in the placenta of the mother. (Fig. 155.) It is taken to that organ by the hypogastric arteries, from the internal iliac arteries. 2. It is returned from the placenta by the umbilical vein, as follows : (i) To the ascending vena cava by the ductus venosus ; (2) to the portal vein to traverse the liver, and finally reach the ascending vena cava by the hepatic veins. 3. The blood from above the diaphragm reaches the heart by the descending vena cava, as in the adult. 4. The blood from the descending vena cava passes through the auricle to the ventricle, and thence out through the pulmonary artery ; the lungs not being yet fitted for purifying, the blood is taken by the ductus arteriosus to the aorta. 5. The blood from the ascending vena cava passes through the foramen ovale (Fig. 154) to the left auricle, thence to the left ventricle, and out by the aorta. The circulatory apparatus of the fcetus possesses : 1. The umbilical vein brings blood from the placenta. 2. The hypogastric arteries conveys blood to the placenta. 3. The ductus venosus takes blood to the vena cava. 4. The ductus arteriosus connects the pulmonary artery and aorta. 5. The foramen ovale is an opening between the auricles. All of these structures forming the circulatory apparatus of the fcetus are set aside at birth, when the lungs become the aerating organ for the blood. By non-use these structures lose their specific characters they become obsolete. They obtain in the adult as : 1. Remains of the umbilical vein, the round ligament of the liver. 2. Remans of the hypogastric arteries near the urachus. 3. Remains of the ductus venosus on under surface of liver. 4. Remains of the ductus arteriosus between aorta and pulmonary artery. 5. Remains of the foramen ovale in posterior wall of auricle. What is a fcetal vestige? The fibrous remains in the adult of an organ that under the conditions of the fcetus in utero was a necessary organ or part. The umbilicus and urachus are foetal vestiges. What are the grand divisions of the thorax / The thorax may be subdivided into a pulmonary part, occupied by the lungs, and a mediastinal part, not occupied by the lungs. Is the word thorax synonymous with trunk / No ; thorax is the cavity above the diaphragm ; trunk means the whole body except the head, neck, and extremities. Explain the superior mediastinal space. This is a space bounded above by the superior aperture of the thorax ; below by a plane limited in front by the manubrio-gladiolar articulation and behind by the body of the fourth thoracic vertebra ; in front by the manubrium ; behind by the four upper thoracic vertebme ; laterally by the pleural sacs. This space 222 PRACTICAL ANATOMY. contains the following structures, which you may find on your work : (i) The thoracic portion of the trachea ; (2) the thoracic portion of the oesophagus ; (3) the thoracic portion of the thoracic duct ; (4) the transverse part of the aortic arch ; (5) the imal and innominate arteries ; (6) the thoracic portion of the left subclavian artery ; (7) the innominate veins, and the superior vena cava ; (8) the terminations of the internal mammary veins ; (9) the terminations of the inferior thyroid veins ; (10) the superior intercostal vein of the left side ; (i i) the two pneumogastric or vagi nerves; (12) the two phrenic and cardiac nerves; (13) the left recurrent or inferior laryngeal nerve; (14) thymus gland in the foetus and remains of the thymus in the adult. Describe tJie pericardium. It is a fibro-serous sac surrounding the heart. The pericardium is cone- Innominate Right pulmonary vein RIGHT AURICLE RIGHT AURICLE APPENDIX Right coronary Branch to anterior wall of right ventricle ( pre- ventricular) Right marginal artery and vein (vein of Galen) Lfft carotid Left subclavian Left pulmonary vein LEFT AURICULAR APPENDIX Left marginal artery Anterior intervenlriciilar branch of the great car- diac vein Left coronary (interven- tricular) Commencing ra/' /) t >ttg/ds. Turn the divided ends of the rectus aside and trace out the branches of the deep epigastric artery. ABDOMEN. 233 Hesselbach's triangle is of surgical importance because direct inguinal hernia passes through it. (Fig. 165.) It is bounded internally by the rectus, externally by the deep epigastric artery, below by Poupart's ligament. See, now, that the con- joined tendon of the internal oblique and transversalis stretches across the inner two-thirds of this triangle. Hence this tendon may become one of the coverings of a direct inguinal hernia. 1 . Points of surgical interest. The inguinal canal, since, physiologically, it transmits the male spermatic cord and its homologue, the round ligament of the uterus ; since, pathologically, in- guinal hernia and diseases of the cord are interrogated here. 2. Importance of tlie umbilictts. This is a physiological cicatrix or scar, marking the aperture through which passed the vessels that made up the umbilical cord, or funis, in the child before birth. These vessels were the right and left hypogastric arteries (branches of the internal iliacs) and the umbilical vein. The arteries took blood to the placenta for aeration ; the vein returned this blood aerated. You will find internally in adult dissections remains of these three vessels centering at the umbilicus. 3 . Further importance of umbilicus. In both adult and child it may be the location of umbilical hernia. 4. Give nerve-supply of the abdominal muscles. The six lower thoracic nerves, through their anterior primary divisions, assisted by the ilio-hypogastric and ilio-inguinal nerves from the lumbar plexus. They also supply the skin covering these muscles. 5 . Give the blood-supply of the abdominal ivalls. This is both abundant and important, (i) The deep epigastric ; (2) the internal mammary ; (3) the lumbar arteries ; (4) the intercostals ; (5) the deep circum- flex iliac ; (6) the superficial circumflex iliac ; (7) the superficial epigastric. The deep epigastric, a branch of the external iliac, anastomoses in the substance of the rectus muscle with the superior epigastric branchof the internal mammary artery, a branch of the subclavian artery. 6. Function of abdominal muscles. (i) They protect from violence and temperature changes the organs in the abdominal cavity ; (2) they assist internal organs to discharge their contents, in that they excite peristalsis a physiological Crede ; (3) they, by their various contractions, alter the relations between the thorax and abdomen ; (4) they are strongly analogous to structures above the diaphragm. The external oblique is analogous to the external intercostals ; the internal oblique to the internal inter- costals ; the transversalis to the triangularis sterni ; the rectus to the sternum ; the linese semilunares to the chondra, vertically ; the lineae transversae to the cos- tal cartilages ; their nerve- and blood-supply are strongly analogous, while func- tions conform to local demands and structure is modified accordingly. Important Attachments and Relations. Notice carefully the following, and demonstrate on your dissection the following points : 1. Each of the three broad muscles has (i) an outer muscular part, and (2) an inner aponeurotic part ; the latter are inseparably united, the former may be separated from each other. 2. The conjoined aponeuroses of all three planiform muscles form the verti- cal mid-line of the abdominal walls, known as linea alba abdominis. 3. The two inner muscles are attached to the upper surface of Poupart's ligament for about one-half the length of this (the outer one-half), and then leaving the same arch over the spermatic cord, forming the roof of the inguinal canal, and are inserted into the pubic crest and inner part of the ilio-pectineal line. 4. Between the muscular parts of the internal oblique and transversalis muscles is located a meagre plexus of nerves, from which the abdominal muscles 16 234 PRACTICAL ANATOMY. are supplied. The deep internal circumflex artery and its veins are also found here. 5 . Give the origin and insertion of the external oblique. Origin. The outer surface of the eight lower ribs about their middle by a series of nearly horizontal lines which, after crossing each rib obliquely down- ward and backward, extend for a short distance along its lower border. Insertion. (i) By a strong aponeurosis along the whole of the linea alba; (2) the front of the os pubis close to the symphysis ; (3) the spine of the pubes and the adjacent part of the ilio-pectineal line ; (4) the deep fascia of the thigh in a thickened band which stretches from the spine of the pubes to the anterior superior spine of the ilium ; (5) the anterior half of the outer lip of the crest of the ilium ; (6) at the lower part of the linea alba some of the fibres (the trian- gular fascia] stretch across the middle line, and are inserted into the front of the crest of the pubes and the inner part of the ilio-pectineal line of the other side. 6. Give origin and insertion of internal oblique. Origin. (i) The outer half of Poupart's ligament ; (2) the anterior two-thirds of the space intervening between the inner and outer lips of the crest of the ilium ; (3) the outer and posterior aspect of the aponeurosis of the transversalis abdom- inis (which aponeurosis is also called the lumbar fascia). Insertion. (i) For about one inch into the inner extremity of the ilio-pecti- neal line ; (2) the anterior border of the crest of the pubes ; (3) the whole length of the linea alba ; (4) the lower borders of the cartilages of the last three ribs. 7. Give origin and insertion of transversalis. Origin. (i) The inner surface of the cartilages of the last six ribs, close to their junction with the ribs, by processes which interdigitate with the attachments of the diaphragm ; (2) the strong aponeurosis called the lumbar fascia, which arises (a) by its anterior layer from the front of the transverse processes of the five lumbar vertebrae, (^) by its middle layer from the tips of the transverse processes of the five lumbar vertebrae, (c] by its posterior layer from the general vertebral aponeurosis which is attached to the spines of the thoracic, lumbar, and sacral vertebrae ; (3) the anterior two-thirds of the inner lip of the crest of the ilium ; (4) the outer third of Poupart's ligament. Insertion. (i) The whole length of the linea alba ; (2) the anterior border of the crest of the pubes ; (3) the inner end of the ilio-pectineal line for about one inch and a half. 8. Give origin and insertion of the rectus. Origin. By two tendons: (i) The larger or outer head arises from the whole of the crest of the pubes ; (2) the inner head crosses the middle line of the body, and arises from the fibrous structures lying in front of the symphysi> pubis. Insertion. (i) The anterior surface of the tip of the fifth rib ; (2) the front ot the costal cartilages of the fifth, sixth, and seventh ribs ; sometimes also (3) th< deep posterior surface of the ensiform cartilage near its outer border. Anatomy of Inguinal Hernia. There are two varieties of inguinal hernia, founded on the idea of internal to or external to the deep epigastric artery, a structure already seen in your dissection. The name direct inguinal is given when a hernia comes through Hesselbach's triangle. In this case the coverings are: (i) Peritoneum ; (2) transversalis fascia ; (3) conjoined tendon; (4) inter- columnar fascia ; (5) superficial fascia ; (6) skin. The name oblique is given when the hernia enters the canal by the internal abdominal ring, in the transver- salis fascia, external to the deep epigastric artery. It has these coats : (i) Peri- toneum ; (2) subserous fatty connective tissue ; (3) infundibulum ; (4) cremasteric muscle; (5) intercolumnar fascia ; (6) superficial fascia ; (7) skin. This variety of hernia follows the course taken by the testicle in its descent, and receives the ABDOMEN. 235 same kind of investments. As before stated, these coats are simply certain parts of the walls which have receded before the hernia in its descent. Describe tJic ilio-liypogastric nerve. It is a branch of the lumbar plexus. It is known also as the superior mus- culo-cutaneous nerve. It crosses the quadratus lumborum muscle, gains the space between the transversalis and internal oblique muscles, and divides into (i) an iliac branch, which supplies the skin over the gluteal region ; (2) a terminal hypogastric branch, that passes between these two muscles i. c\, the internal oblique and transversalis to near the mid-line, where it comes through the abdominal walls an inch above the external abdominal ring. Describe the ilio-inguinal nerve. You find this nerve anterior to the spermatic cord. It is distributed to the Epigastric artery Internal abdom- inal ring Border of the posterior part of the sheath of the reetus (fold of Doug- las) Posterior surface of reetus 'Jjitf Conjoined tendon in the triangle of Hesselbach Obliterated hypo- gastric artery Lymphatics in crural rings External iliac artery FIG. 164. DISSECTION OF THE LOWER PART OF THE ABDOMINAL WALL FROM WITHIN, THE PERI- TONEUM HAVING BEEN REMOVED. (Wood.) scrotum and labia majora, and to the inner and upper part of the thigh. It is a branch of the lumbar plexus. It runs near to and plexifies with the preceding nerve, between the internal oblique and transversalis. Describe t/te genilo-crural nerve. This is seen behind the spermatic cord, in the canal ; after the cord emerges from the external abdominal ring, the genital branch of the genito-crural nerve is seen behind the cord. This supplies the cremaster muscle with motion. The crural branch of the genito-crural nerve goes to the skin over the mid-front of the thigh half way to the knee. INTERIOR VIEW OF ABDOMINAL WALLS. Make an incision on each side, from the lower part of the umbilicus to the anterior superior spine of the ilium, through the entire remaining abdominal wall. Turn the V-shaped flap thus formed forward, and at the same time lift it upward 236 PRACTICAL AX A TO MY. and put it on the stretch as much as possible. You are to see and study the following structures through the peritoneum (do not remove this yet) : 1. The plica urachi a peritoneal fold covering the remains of the urachus. This is in the mid-line from the summit of the bladder to the umbilicus. 2. The plica hypogastrica, covering the remains of the hypogastric arteries. 3. The deep epigastric arteries and veins, passing upward and inward to enter the sheath of the rectus muscle by passing under the fold of Douglas. 4. Poupart's ligament and the external iliac vessels leaving the pelvis, to be called femoral in the thigh. Here, too, see the external iliac artery giving oft" its two branches, the deep epigastric and the internal circumflex iliac branch. 5. The internal abdominal ring, to which you may see plainly the con- stituents of the spermatic cord coming viz., the vas deferens, the spermatic vessels. Locate this ring just to the outer side of the deep epigastric artery. 6. The femoral canal, called also crural canal. Find this to the inner side of the femoral vein, between Poupart's ligament above and the bone below. To its inner side you will feel the sharp falciform margin of Gimbernat's ligament. This canal is in the femoral sheath, and occupied by fat and connective tissue called the septum crurale or septum femorale. 7. Inguinal and Femoral Fossae. There are three of these. The internal is between the remains of the urachus and hypogastric artery ; the middle inguinal fossa is between the remains of the hypogastric artery and the deep epigastric artery. The importance of these two fossae is they permit direct inguinal hernia to form. The external inguinal fossa is external to the deep epigastric artery and corresponds to the situation of the internal abdominal ring, and is the location of oblique inguinal hernia. In this connection notice the femoral fossa. This corresponds to the femoral ring, and marks the location of femoral hernia. DISSECTION OF FEMORAL HERNIA. Find the femoral fossa, covered by peritoneum, just below Poupart's liga- ment, and internal to the femoral vein. Now remove the peritoneum, by pulling the same gently backward and downward. Take the forceps and break up the connective tissue in the femoral canal, the depression corresponding to the femoral fossa just mentioned and internal to the femoral vein. We will consider femoral hernia with reference to (i) the femoral sheath ; (2) the femoral canal ; (3) the coverings of femoral hernia ; (4) contents of the canal ; (5) the relations to other structures ; (6) anatomical factors concerned in reduction ; (7) the deep crural arch. The femoral sheath is formed under Poupart's ligament by the meeting and union of the fascia transversalis in front of the femoral vessels and of the iliac fascia behind the femoral vessels. As you will demonstrate on your cadaver, these fasciae unite on the outer side of the femoral artery very close to the vessel ; on the inner side of the vein, however, they leave an interval, one-half of an inch in width, between the femoral vein and Gimbernat's ligament. (Fig. 165.) This interval is the femoral canal. The deep crural arch extends in an archiform manner across the femoral sheath, strengthening thereby the transversalis fascia. It is inserted into the spine of the pubes, and may be looked upon as a slip of contribution from the transversalis fascia. The femoral sheath contains the following structures : ( i) The femoral arte on the outer side; (2) the femoral vein in the middle: (3) the femoral can internal to the vein. The beginning of the femoral canal not the beginning o the sheath is the femoral ring. The femoral canal contains some connective tissue that you just broke up with your forceps. The special name for this is the septum femorale or septum crurale. Make note of this, for it forms one of the coverings of femoral hernia. I wish to make emphatic the difference nou between the contents of the femoral sheath and the contents of the femoral canal. The canal itself is in the sheath. The femoral ring and its relations are the beginning of the femoral canal, just as the brim is the beginning of a cup. The ring has certain definite bounda- ries and relations, which you must both demonstrate on your work and commit thoroughly to memory. In figure 165 you can study these. Internal to the ring is the sharp falciform edge of Gimbernat's ligament. This, as you can easily demonstrate on your work, is a reflection of Poupart's ligament on to the ilio- pectineal line. To the outer side of the ring is the femoral vein. Above the Deep circumflex iliac artery External iliac artery External iliac vein Obturator foramen B Internal ring, with spermatic vessels cut short in it Deep epigastric artery Lymphatic gland in femoral ring The obturator artery, given off" from the external iliac with the deep epigastric, descends to gain the obturator foramen, but at a safe distance from the femoral ring The obturator artery, coming off" from the deep epigastric, HUM a course so near to the femoral ring that it would very likely be divided by the bistoury intro- duced front without to diritlr-. the base of Gimbernaf's liga- ment, the cause of the constric- tion FIG. 165. IRREGULARITIES OF THE OBTURATOR ARTERY. (After Gray.) ring is Poupart's ligament. Below the ring is the horizontal part of the os pubis, covered by the pectineus muscle and its aponeurosis. You will also see the deep epigastric artery arising from the femoral artery and passing upward and inward across the upper part of the femoral ring. In a certain number of cases the deep epigastric artery gives off the obturator artery, which passes either to the outer side of the ring, as in A, figure 165, or to the inner side, as in B. In either case it would complicate an operation for reduction of femoral hernia. You will note on the cadaver that the obturator artery and nerve lie on the 2 3 8 PRACTICAL ANATOMY. outer wall of the pelvis. The artery is, as a rule, a branch of the internal iliac. It forms an exception to the rule in the figures given here. The coverings of femoral hernia from within outward are: (i) The perito- neum ; (2) the subperitoneal connective tissue ; (3) the septum femorale ; (4) the femoral sheath ; (5) the cribriform fascia the deep layer of superficial fascia that covers the saphenous opening in the fascia lata ; (6) the superficial fascia ; (7) the skin. Factors concerned in reduction of hernia are those that tend to tighten the canal. These are : (i) The saphenous opening ; (2) the iliac and pubic portions of the fascia lata ; (3) the external oblique muscle and its lower portion Pou- part's ligament. These structures that tend to strengthen a succession of ana- tomical weak points, determining the course of a femoral hernia, may all be dis- empowered by flexion of the thigh on abdomen ; flexion of leg on thigh ; adduc- tion of thigh. Demonstrate this on your work by placing your finger in the femoral canal, and let an assistant produce first abduction and extension, and adduction and flexion, when the scissor-like action of Poupart's and Gimbernat's will be appreciated. THE PERITONEUM. The inquisitive student instinctively asks himself the following simple ques- tions, which I will here answer fully enough for dissecting-room purposes : i . What kind of a structure is peritoneum and ivhere is it fou)id / Peritoneum is a serous membrane found in the abdominal cavity only. LACTEALS Veins FIG. 166. VESSELS OK THE SMALL INTESTINE. 2. What is the appearance of peritoneum ami Jiow may I recogitize /// Peritoneum is smooth, moist, glistening. You can recognize it by its loca- tion and its appearance. Its most distinctive feature is its location in the abdom- inal cavity ; removed from this cavity you could not distinguish it from other erous membranes pleura and pericardium. 3. \Vliere will f sec peritoneum on opening the abdominal cavity / You will see it forming the innermost layer of the wall you cut and turned ABDOMEN. 2 39 back smooth, moist, glistening, and attached ; you will see it covering every organ in the abdominal cavity partially or completely. If by force of circum- stance organs lose all or some of their peritoneal covering, this is no fault of the peritoneum. Remember, the primitive relation of every organ to peritoneum is behind partially or completely covered thereby. (Figs. 167 and 168.) Figure 167 shows aorta giving three branches to three organs. The organ in the centre is for practical purposes completely invested by peritoneum. Between the two parts of the peritoneal fold is (i) The organ ; (2) the vessels that take blood to and from the organ ; (3) the nerves that innervate the organ ; (4) the VISCERAL LAYER OF PERITONEUM PERITONEAL CAVITY PARIETAL LAYER OF PERITONEUM KIDNEY AND ITS RENAL VESSELS The aorta FIG. 167. SHOWING PARTIAL AND COMPLETE INVESTMENT OF ORGANS BY PERITONEUM. lymphatics that scavenger the organ. The organ has only one place where it is accessible only one communication with the wall. Examine the cadaver, take up a portion of the small intestine, find the superior mesenteric artery, and trace it down between its two parts of the peritoneal folds. Now, with your forceps, make a rent in one side of the mesentery, examine, and find an artery, a vein, nerves, glands, and fat, as represented in figure 166. 4. Explain implantation of meso-structures. That part of the alimentary canal which remained in its original mid-line of the body as the greater part of the small intestine and rectum may be said to be an example of primitive implantation ; those parts which contracted adhesions PARIETAL LAYER OF PERITONEUM PERITONEAL CAVITY The. aorta FIG. 168. SHOWING RETRO-PERITONEAL LOCALITY. to localities other than the mid-line, may be said to be examples of acquired implantation. The colon and duodenum are examples of this latter variety. 5. From ivliat source does the peritoneum derive its blood-supply f It will be presently seen that the abdominal aorta has parietal branches and vis- ceral branches. The parietal branches, as the lumbar and phrenics, supply the peri- toneum covering these walls ; the visceral branches supply the peritoneum cover- ing the organs. Peritoneal arteries are, then, of two classes visceral and parietal. 6. Explain peritonea! investment of organs. 240 PRACTICAL ANATOMY. This is as follows : (i) Organs may simply be behind the peritoneum, as arte- ries and veins, in which case we say they are covered by this membrane. (Fig. 1 68.) They have not grown sufficiently in thickness to produce any appreciable displacement of the peritoneum. Figure 168 shows the aorta behind the peri- toneum, but producing no bulging forward of the peritoneum. (2) Organs may produce appreciable bulging forward, as in figure 167, when we say they a im- partially invested. Now examine the kidney and you will find its relation to the peritoneum represented in figure 167 in the two organs on the two sides. 7. What determines the degree of peritoneal investment f The height to which any organ grows determines this. The peritoneum pushed ahead of the organ is called the mesentery of the organ and the peritoneal investment. Mesenteries may be long or short. The height to which an organ PARIETAL LAYER OF PERITONEUM The aorta FIG. 169. In this figure an organ has grown to a considerable height and a long mesentery is the result. PARIETAL PERITONEUM VISCERAL PERITONEUM The aorta FIG. 170. In this figure, a is an organ completely invested by peritoneum. Its mesentery grows high and falls on />, an organ partially invested by peritoneum. At the contact point of a and b loss of epithelium occurs. Parts of organs, or entire organs, which once possessed peritoneal investment, but subsequently lost the same in this manner, are said to be retro-peritoneal, or to have no peritoneal investment. An example is to be seen in the case of the right kidney, where the duodenum and colon bear the above relation (Fig. 170) to the anterior surface of this organ. grows determines, then, both the degree of investment and the length of the mesentery. 8. H&W arc the abdominal muscles classified? As vertical and horizontal. The pyramidalis and rectus abdominis are ver- tical ; the external and internal oblique and the transversalis are horizontal. 9. Xamc the abdominal -iccak points in tlic trails of tlic abdominal cavity and give their practical importance in surgery. (i) The inguinal canal, limited internally by the internal abdominal ring, and externally by the external abdominal ring. This canal lodges the spermatic cord of the male and the round uterine ligament of the female. It is the succession of weak points that formed the line of least resistance to the descending testicle. ABDOMEN. 241 This canal acquires surgical importance in inguinal hernia, of which there are two arbitrary divisions direct and oblique : the former being internal to, the latter being external to, the deep epigastric artery. (2) The femoral canal, being that part of the initial three-quarters of an inch of the femoral sheath unoccupied by the femoral vessels. (Fig. 165.) Normally, the canal is occupied by a fatty connective tissue, with or without a lymphatic gland. The entire amount of this connective tissue called technically the septum crurale, or septum femorale weighs three grains. The surgical importance of this septum is due to the fact that it is inferred to form one of the coverings of a femoral hernia. Just why rational medical literature should continue to dignify this frail structure, and place it in the same category with such structures as Gimbernat's and Pou- part's ligaments, the femoral sheath, and the skin itself, is difficult to determine. (3) The umbilicus is the point where the two hypogastric branches of the inter- nal iliac arteries and the umbilical vein came together to form the umbilical cord, a foetal arrangement that took impure blood to the placenta and returned in its stead the same blood plus O and minus CO 2 . 10. Where is the spermatic cord made up and of what structures does it consist ? It is made up at the internal abdominal ring, to the outer side of the deep epigastric artery, by the coming together of the spermatic artery, the spermatic veins, the deferential artery, and the excretory duct of the testicle the vas PARIETAL PERITONEUM VISCERAL PERITONEUM MESENTERIC MARGIN CAVITY OF PERITONEUM MESENTERIC STALK MESENTERIC ROOT The aorta FIG. 171. SHOWING SIMPLE VISCERAL AND PARIETAL LAYERS OF PERITONEUM WITH CAVITY BETWEEN THEM. deferens. These structures are loosely bound together by connective tissue. In practical dissection the cord is found below and external to the pubic spine, not as a cord, but as a flattened band. The cord lies on the shelved inner and upper part of Poupart's ligament, in the inguinal canal. The function of the spermatic artery is to supply the testicle with blood, from which the testicle secretes semen. The spermatic veins return the blood to the general circulation, the right being tributary to the ascending vena cava, the left to the left renal vein. The vas is the conduit that leads the semen to the vesiculae seminales at the base of the bladder. The artery of the vas nourishes this conduit and inosculates with the spermatic artery. 1 1 . Tell all you can about tJie femoral sheath. It is composed of two fasciae that come down out of the abdominal cavity, one in front of and the other behind the femoral vessels. These fasciae surround the vessels and take the name "femoral sheath." 1 2. What are the fascia t/iat form the femoral sheath and why are they so called? The one in front of the femoral vessels is the transversalis ; the one behind the vessels, the iliac fascia. They are named in accordance with the rule governing the naming of deep fasciae i. c., according, in this case, to the name of the muscles. 2 4 2 PRACTICAL ANATOMY. 13. Do the lumbar arteries assist in furnishing the peritoneum with blood / Yes ; the same arteries that supply the walls, supply the peritoneum cover- ing the walls. 14. What can you say of the lumbar arteries f They are four in number on each side. They are analogous to the intercos- tal arteries. They arise from the abdominal aorta. The right are longer than the left lumbar arteries. These arteries are small when compared to their homo- logues, the intercostals. The lumbar arteries lie behind the abdominal sympa- thetic chain. According to their distribution, the lumbar arteries are classified as dorsal branches and abdominal branches. Each has specific relations and course. The dorsal branches pass out between the transverse processes of the lumbar vertebrae, with the posterior primary divisions of the lumbar nerves, and attended by their corresponding lumbar veins, to be distributed to the spinal cord, passing through the intervertebral foramina; to the muscles and skin of the back ; and to the lumbar vertebrae in this region. The abdominal branches of the lumbar arteries pass behind the sympathetic chain and behind the quadratus lum- borum muscle. They are distributed to the quadratus lumborum and psoas magnus muscles and to the abdominal walls. I 5 . What can you say of the anastomosis of the lumbar arteries / The dorsal branches anastomose with each other and with the intercostals. The abdominal branches of the lumbar arteries anastomose : (i) Above with the lower intercostal arteries ; (2) below with the ilio-lumbar and circumflex iliac ; (3) in front with the epigastric and internal mammary. 1 6. If the abdominal aorta were ligated just above the bifurcation, how could the blood reach the loiuer extremities ? Through two channels: (i) The epigastro-mammary arch ; (2) the lumbo- circumflex anastomotic arch. 17. Describe the epigastro-mammary anastomotic arch. An arch formed by anastomosis between the deep epigastric artery, a branch of the external iliac, and the internal mammary artery a branch of the subclavian. This union occurs in the rectus abdominis muscle. 1 8. Describe the lumbo-circumflcx anastomotic arch. It is an arch formed by anastomosis between the lumbar arteries, branches the abdominal aorta, and the deep internal circumflex iliac artery a branch of th< external iliac. The arteria sacra media is the sacral representative of the lumbar arteries. It is to the aorta what the coccyx is to the vertebral column, what the ensiform car- tilage is to the sternum the exhaustion. It is the representative of the caudal artery of some animals. Its small branches are distributed in the same manner as those of the lumbar region. 19. What can you say of the lumbar veins f They accompany the lumbar arteries arid are tributary to the ascending \vn; cava. 20. How would you explain the nerve-supply of the peritoneum / The same nerves that supply muscles that enclose a serous cavity supplj the serous membrane enclosed. This principle was pointed out by Hilton am Van der Kolk. The full law, as given previously, applies not only to serous but to mucous membranes as well. 21. What are the functions of peritoneum f It secretes serum for lubrication of opposed surfaces. It is a highly absorp- tive structure. It forms ligaments for holding organs in place. It protect organs against violence. It gives strength to organs which it invests. It con serves heat and piwrnts sudden changes of temperature. 22. Is serum ever secreted in abnormally large quantities f ABDOMEN. 243 Yes, and the terms by which such conditions are designated are hydro-pericar- dium, hydro-thorax, hydro-cephalus, and hydro-peritoneum. 23. What is a peritoneal cavity f The space between the visceral and parietal layers ot the peritoneum. The same is true of any serous cavity viz., it is the space between a visceral and a parietal layer of serous membrane. 24. What do we understand by mesenteric contents ? All the structures between the two surfaces or folds of the mesentery /. e. , in the mesenteric space. The intestine is, of course, the largest structure. (Fig. 1 66.) The vessels, nerves, and glands to and from the intestine are all called mesenteric. They are all embedded in a variable amount of mesenteric fat. Sometimes this fat is so abundant as to completely hide the vessels from view ; at other times the vessels may be seen. 2 5 . Explain tlic primitive alimentary canal. In figure 172 you have a view of the primitive canal and its mesentery in longitudinal section. Will you remember that the mesentery has two layers fade. U< gast.Jiefiat: omcnt I/MES. FIG. 172. DIAGRAM OF THE PRIMITIVE ALIMENTARY CANAL. with the arteries, that make the canal grow, between them ? You see in the figure only one surface of the mesentery. At an early period there is only one gut and one mesentery. This gut is straight, and located in the mid-line and on the pos- terior abdominal wall. The gut grows in proportion to the blood-supply it receives. In figure 172 this primitive mesentery had three important organs between its two layers: (i) The stomach, in the middle; (2) the liver, between the two layers, in front of the stomach ; (3) the spleen, between the two layers, behind the stomach. We see parts of this primitive partition unoccupied (i) in front of the liver; (2) between the liver and stomach ; (3) between the stomach and spleen ; (4) between the spleen and posterior wall. 26. Can ive find evidence in our dissection of the unoccupied parts just referred to ? Yes ; the one in front of the liver is the broad or falciform ligament of the liver. The one between the liver and stomach is the gastro- hepatic or lesser omentum. The one between the stomach and spleen is the gastro-splcnic omentum. 27. Give the difference between omentum and mesentery. 244 PR A CT1CAL A XA TO. MY. In reality there is no difference except an arbitrary one. Each is of peri- toneal origin ; each has two layers ; each escorts vessels and nerves to organs. Omenta connect organ to organ ; mesenteries connect organ to wall. 28. Usage arbitrary. The broad ligament holds the liver to the diaphragm ; the broad ligament ot the uterus holds the uterus to the lateral pelvic walls and floor. They are the mesenteries of these viscera. Usage, however, restricts the use of the word mesen- tery exclusively to the intestines. As you will see, the ascending colon lost its mesentery. The descending colon lost its mesentery, except the rectum, in part, and the sigmoid. The transverse colon retained its mesentery. 29. Define mesentcric attachment primitive and acquired. By primitive attachment of the mesentery we mean attachment in the mid- line, or nearly in the original line of the straight gut. The mesentery of the small intestine is, for practical purposes, art example of primitive attachment ; the rectum is primitive in attachment. The duodenum, stomach, and colon have acquired attachments. aastro-liejiat. oment. FIG. 173. DIAGRAMS SHOWING (A) THE FORMATION OF THE GREAT OMENTUM, AND () THE TION OF THE INTESTINAL CANAL. - 30. cance ? What is differentiation of the alimentary canal and its physiological signifi- In the evolution of the alimentary canal, differentiation is the process whereby the primitive straight gut undergoes a change which determines large and small intestines. The ileo-caecal junction is the place where this change took place. (Fig. 172.) The physiological significance seems to be simply a physiological division of labor, whereby the small intestine is specialized for digestive purpose -s, the large intestine for disinfecting, deodorizing, storage, and extrusive purposes. 3 1 . Wliat is rotation .' It is the process by which the upper border of the small intestine (Fig. 173) is turned from you, from left to right, and brought out toward you under the arch of the transverse colon (Fig. 173), so as to be, when completely turned, as tr.Mire 173. In figure 172 both large and small intestines have a common con- tinuous mesentery, as you see. In figure 173 they still have the same mesen- tery, with this difference : that for the small intestine is twisted on itself one-half around. The pivot about which this rotation took place is seen in figure 172 the superior mesenteric artery. Kxaminc figure 172 and sec the jejunum. Trace this down to the caecum. ABDOMEN. 245 This is an explanation of the fact you can demonstrate on the cadaver : that the small intestine is almost completely surrounded by the ascending transverse and descending parts of the colon. Show this on your work. 32. Formation of greater and lesser peritoneal cavities. In figure 172 you have the primitive peritoneal partition dividing the abdom- inal cavity into a right and a left half. In front of the stomach you see the gastro- hepatic omentum ; behind the stomach the mesentery, which now takes the specific name meso-gaster. You see the initial end of the small intestine (duo- denum), and below this the remainder of the small intestine and all the large intes- tine, attached by a common mesentery ; that peritonium, however, which corres- ponds to the colon is called meso-colon, and that which corresponds to the small intestine is called mesentery. Can you now distinguish the three meso-structures ? Can you remember that each has two layers, between which are located the mesen- teric arteries and other contents ? Can you remember that the attached margin of this meso-gut now extends from the floor of the pelvis to the diaphragm, in the mid-line ? Can you remember that the intestinal margin of the meso-gut must become longer, in proportion to the growth of the intestine, large and small ? Now you are on the left of this partition. Thus far the space on the right is as great as that on the left. The arrow in figure 173 is represented as simply coming through an artificial opening, to aid you in remembering the space on the other side of the partition. Now imagine you took hold of the partition, the meso-gaster, and pulled toward you in the direction of the dotted line. Would you not, by continued pulling, produce a bagging-out on your side of the parti- tion, and a consequent depression or bagging-in on the other side ? Can you imagine, now, if you pulled long enough, the beginning of the depression or sac on the other side must become smaller and smaller? The hole on the other side would admit you to this little sac thus formed by your pulling. In anatomy the name of this hole is the foramen of Winslow. It 'leads to the sac you have just formed. This sac is the lesser cavity of the peritoneum ; all the space outside of this is the greater cavity of the peritoneum. 33. What parts of the abdominal viscera, in the adult, have lost their peritoneal covering by pressure atrophy, as referred to in a preceding paragrapJi / No two cases are exactly alike in this regard. Still, the following represents a general average, as you will meet these cases in the dissecting-room : (i) The posterior part of the descending colon rests on the posterior wall of the abdomen, consequently there is adhesion, with loss of the specific epithelial element. (2) The ascending colon, the second and third parts of the duodenum, the colic and duodenal elbows to be presently explained, rest on the peritoneum, partially in- vesting the right kidney, and here is peritoneal loss. The second part of the rectum is adherent to the anterior surface of the sacrum, and here is peritoneal loss. Each case is a law unto itself, in a measure ; but the student with an ink- ling of the developmental principles, as given in the foregoing, and as elaborated in Morris, can soon acquire a facility in locating on his dissections, those peri- toneal ruins, whose presence forms one of the mainstays for the receptacular part of the alimentary canal, whose absence belongs to the rarest of rare developmental freaks. 34. Does rotation occur in every case ? Faulty rotation, and even failure to rotate, may occur. One interesting case, found recently by the author, showed the caecum and the entire colon on the left side, the small intestine in or near the right iliac fossa. 35. Are any special organs developed from the alimentary canal .' The liver and pancreas are developed from the duodenum ; the former grows into the mesentery in front of the stomach, the latter into the posterior meso-gaster. You will see their ducts open in common into the second part of the duodenum. 246 PRACTICAL ANATOMY. SHORT SUMMARY OF PERITONEAL CONSIDERATIONS. 1. The complex adult alimentary canal and its complex peritoneal invest- ing membrane are evolved from a simple straight gut and a simple straight mes- entery. 2. The abdominal part of this canal in the foetus extends from the diaphragm to the anus on the posterior wall of the abdominal cavity in front of the vertebral column. It is attached to the anterior wall, as far downward as the umbilicus, under the name of ventral mesentery. 3. The stomach appears as an enlargement in the canal, and its dorsal mesen- tery is called meso-gaster. 4. The upper part grows much more rapidly than the lower, receiving a more liberal blood-supply. In round numbers, the small intestine is the product of the superior mesenteric artery ; the large intestine is the product of the inferior. 5. At an early period the liver is in front of the stomach and the pancreas behind. The liver grows into the ventral mesentery, the pancreas into the pos- terior meso-gastrium. The primary mesentery of the pancreas fuses with the posterior body wall. 6. As the liver and spleen become larger, and as the bowel begins to rotate about the superior mesenteric artery, the stomach assumes a transverse position, the anterior border becomes the lesser curve, posterior border becomes the greater curve, the left surface becomes the anterior, and the right surface becomes the posterior. 7. The small intestine rotates from left to right in such a way that the large intestine extends from right to left and crosses the small intestine near the stomach. 8. Rotation accounts for the duodenum passing under the second or trans- verse stage of the colon and apparently through its transverse meso-colon. 9. The meso-gaster becomes the greater omentum, consists of four layers, grows out from the greater curvature of the stomach. 10. The duodenum and ascending and descending colon lose their mesen- teries. ABDOMINAL CONTENTS. Cut slightly to the left of the umbilicus, then through the linea alba to the ensiform cartilage. It may be necessary to divide the cartilages of the two or three lower true ribs to make ample room. Make the following observations before any further dissecting is done : 1. Find the broad ligament of the liver in the longitudinal fissure of this organ. See the round ligament of the liver in the free margin of the broad. This is the remains of the umbilical vein that brought aerated blood from the placenta during intrauterine life. 2. Locate the stomach, I her, spleen, and transverse colon. Lift the lower margin of the liver upward, and at the same time pull the stomach downward ; now see the peritoneal connection between the liver and stomach the gastro- hcpatic omentum or lesser amentum. Notice the peritoneal connection between the stomach and the colon. This is the Castro-colic omentum or great omentum. See the peritoneal connection between the left end of the stomach and the spleen. This is the Castro-splenic omentum. Folds of peritoneum that connect organ to are called omenta, and the three above given are the omcnta. Abdominal aorta LEFT CRUS OF DIAPHRAGM ISOPHAGEAL BRANCH RIGHT CRUS Of DIAPHRAGM Cystic artery Sight phrenic artery HEPATIC DUCT CYSTIC DUCT Splenic artery COMMON BILE DUCT Pyloric artery Gastro-duodenal artery Superior pancreatico- duodenal artery HEAD OF PANCREAS Inferior pancreatico- duodenal artery Right gastro-epiploic artery Left gastro-epiploic artery FIG. 174. THE CCELIAC ARTERY AND ITS BRANCHES. BLADDER GREAT OMENTUM SMALL INTESTINE FIG. 175. THE VISCERA AS SEEN ON FULLY OPENING THE AIJDOMEN WITHOUT DISARRANGEMENT OF THE INTERNAL PARTS. (After Sarazin.) 247 248 PRACTICAL ANATOMY. 3. Three Divisions of tlie Colon. The divisions of the colon are ascending, transverse, descending, sigmoid, and rectum. The ascending colon extends from the right iliac fossa to the hepatic flexure. The transverse colon extends from the hepatic flexure to the lower margin of the spleen the splenic flexure. The descending colon extends from the splenic flexure to the brim of the pelvis. Notice the manner in which the three parts of the colon are held in place. The meso-colon of the transverse is quite long ; that of the ascending and descending is very short; in fact, the nature of the union is one of adhesion rather than mesenteric, in the two latter. Folds of peritoneum that bind organs to walls are called mesenteries. The continuation of the descending colon below the pelvic brim, to a point opposite the second piece of the sacrum, is called the sigmoid. Lift it up and see the great length of its mesentery called meso- sigmoid. 4. Differential Diagnosis Between Large ami Small Intestine. Inflate the large intestine (Fig. 175) and see the following differential points possessed by large intestine but not possessed by small intestine : (i) Fatty masses. (2) Longi- tudinal muscular bands, three in number, and at equal distances from each other. Each will lead to the appendix. (3) Sacculations, produced by contraction exerted by the longitudinal bands. 5- Jejunum, Ileum, and their Mesentery. Compare your dissection with fig- ure 175 and you will observe that the three parts of the colon almost surround the large central mass of small intestine. Collect this mass in your hands and find the upper end of the jejunum going through the transverse meso-colon oppo- site the third and fourth lumbar vertebra to become duodenum ; the lower end you will find near the right iliac fossa, ending in the caecum, forming therewith a junction called the ileo-caecal junction. Lift the whole mass of small intestine upward, to estimate the length of the mesentery. 6. The Duodenum. Turn the transverse colon and great omentum upward. Find the beginning of the jejunum and shut the same off the intestine below this point by a ligature. Now inflate the alimentary canal above this point /. i\, duodenum and stomach. You will now see the transverse part of the duodenum passing behind the superior mesenteric artery and vein. 7. Ciecum and Appendix. You will find the caecum, as a rule, in the righ iliac fossa. Its meso-caecum may be long in one case and short in another. The longitudinal bands traced downward will lead to the appendix. This organ has a peritoneal ligament the meso-appendix. It may occupy a variety of locations. It may hang down in the pelvis across the brim. Its usual posi tion is in an angle between the ileum and the pelvic side of the caecum. A general review will now be made of what you have examined /// situ an studied in the normal position without cutting. 1. You saw, on opening the abdomen, the walls and also the viscera (organs), covered by a very thin, smooth, and glistening membrane peritoneum. The layer covering the walls above, below, in front, behind, and on the sides is called parietal peritoneum ; that covering the organs themselves is called visceral peritoneum. The space between these t\\<> layers is the peritoneal cavity, which contains only a small amount of serum f<>r lubrication. Henceforth you will define a peritoneal cavity as a space between a visivr.il and a parietal laye of peritoneum. (Fig. 171.) 2. On the interior of the abdominal walls you saw, through the thin parirta ; ABDOMEN. 249 peritoneum, the urachus in the mid-line extending from the summit of bladder to the umbilicus. This is the foetal remains of the stalk of theallantois ; it is covered by peritoneum, and the particular name given the ridge or fold in this peritoneum is plica urachi. This opening sometimes fails to close. 3. You saw on each side of the plica urachi the foetal remains of the hypo- gastric arteries ; these are covered by peritoneum, called plica hypogastrica. The triangular depression between these two plicae just noticed is the internal inguinal fossa, and is associated with direct inguinal hernia. 4. You located the deep epigastric artery and veins. To the inner side of this THYROID LUNG LIVER Suspensory ligament SMALL INTESTINE BLADDER LUNG RIGHT AURICLE RIGHT VENTRICLE STOMACH PART OF TRANSVERSE COLON Hypogastric artery FIG. 176. THE VISCERA OF THE FCETUS. (Rudinger.) artery you saw the middle inguinal fossa, associated with direct inguinal hernia ; to the outer side the external inguinal fossa, associated (i) with the beginning of the spermatic cord ; (2) with indirect or oblique inguinal hernia. You saw also that this deep, epigastric artery forms the outer boundary of Hesselbach's tri- angle. 5. You saw the femoral sheath, containing the femoral artery, vein, and femoral canal. These structures you saw leaving the pelvis below Poupart's ligament. The peritoneal depression corresponding to the beginning of the femoral canal the femoral ring is the femoral fossa, and is associated with femoral hernia. 17 250 PRACTICAL ANATOMY. 6. Tlie round ligament of t/ie liver, you will remember, extends from the umbilicus to the liver. It is in the free border of the broad ligament of the liver. It is the foetal remains of the umbilical vein. (Fig. 176.) You will remember that in the child before birth, the placenta purifies the blood, as do the lungs, after birth. The blood is* taken in an impure state to the placenta by the hypogas- tric arteries, and returned pure by the umbilical vein. (Fig. 155.) 7. Three onienta are the gastro-hepatic, or small ; the gastro-colic, or great ; the gastro-splenic. You learned to define omentum as peritoneal folds connect- ing organ to organ. In your dissection you saw the great omentum as a heavy, fatty veil, covering in all the small intestine, and hanging down even into the true pelvis. This may even become a hernia, an omentoccle, and appear at any one of the four fossae described in the foregoing review. 8. The Colon and Its Subdivisions (Fig. 175). The point where differentiation takes place is usually in the right iliac fossa ; still, it may occur above this point. You will see on your work two flexures in the colon the hepatic, at the lower margin of the right lobe of the liver ; the splenic, at the lower margin of the spleen. The transverse colon lies between these two flexures. The descending colon is below the splenic ; the ascending, below the hepatic flexure. 9. You will examine and recall the nature of the colic attachments. That of the ascending, and also of the descending, is in the nature of one structure adherent to another ; their meso-colons, in other words, are short ; hence you are not able to move them freely from place to place, as you can move the transverse colon. On the other hand, the meso-colon of the transverse colon is very long, due to which fact the transverse is the most movable part of the colon. Also recall the definition for mesentery : peritoneal folds binding organ to wall. The meso-sigmoid is also long. 10. Diagnostic of large intestine, you will remember, are the three longitudinal muscular bands of fibres ; the consequent sacculations produced by these ; the fatty masses called appendices epiploicce. The latter are variable in size ; in one case they may be very large, in another quite small ; they are always present on large intestine. Any one of the three bands will lead to the appendix. 1 1. As you will remember, you inflated the duodenum and studied the third part of this organ as it passed behind the superior mesenteric vessels. The remaining part of the small intestine is arbitrarily divided into an upper two-fifths, called jejunum, and a lower three-fifths, called ileum. Jejunum means empty or hungry, and ileum means coiled. There is no practical histological difference between the two. They are held by their mesentery to a line extending from the left side of the body of the second lumbar vertebra, to the right sacro-iliac synchondrosis. In its course it lies upon, as you will presently see, the aorta, vena cava inferior, transverse part of the duodenum, and vertebral column. Yoi will see, then, that the mesentery of the small intestine forms a partition betuvrn the right iliac fossa and the true pelvis; that fluid to the left of this partitioi would be directed into the pelvis, to the right of the same, into the right iliac fossa. Make this experiment. You will now, by dissection, analyze the following localities and structim s 1. The foramen of Winslow. 2. The root-structures of the livrr. 3. The K-ssiT cavity of the peritoneum. 4. The inv.ikT cavity of tin- pi-ntoiu-um. 5. The ascriiding, descending, and transverse duodenum. ABDOMEN. 251 6. The pancreas and splenic artery. 7. The stomach and gastric artery. 8. The liver, hepatic artery, and portal vein. 9. The superior and inferior mesenteric arteries and veins. 10. The anterior relations of the right kidney. 1 1. The anterior relations of the left kidney. 1 2. The root structures of the kidney. 13. Descriptive renal terms. The foramen of Winslow is the communicating passage between the greater and lesser peritoneal cavities. The foramen has definite boundaries, which must be located by each student, and then learned. Surgical operations on the gall ducts of late years have made it imperative for the student of anatomy to have such a thorough knowledge of structures in this locality, that by the sense of touch alone, he may know perfectly both his longitude and latitude. The foramen is variable in shape ; it may be round, semilunar, or triangular. As a rule, it will admit two fingers. Introduce your left index finger and find, in front of your finger, the front boundary the free border of the lesser omentum containing the hepatic root -structures ; behind, the posterior boundary the ascending vena cava and a ligamentous band of peritoneum extending from the BALL BLADDER Hepatic artery Portal vein FIG. 177. RELATION OF STRUCTURKS AT AND BELOW THE TRANSVERSE FISSURE. (Thane.) liver to the right kidney ; above your finger, the caudate lobe of the liver; and below, you will recognize the hepatic artery and the duodenum. The Root-structures of the Liver (Fig. 174). Insert your finger into the foramen of Winslow, and with your forceps plow through the anterior layer of the gastro-hepatic omentum. You will now find three large structures, which a few moves of the forceps will liberate from their bed of connective tissue : (i) To the right side and below, and corresponding to the gall-bladder, the common bile duct ; (2) to the left side and above, the hepatic artery ; (3) between these two, but on a deeper plane, the portal vein. (Fig. 177.) Carefully examine the artery and you will find numerous nerves surrounding the same. They come from the pneumogastric and sympathetic. The connective tissue embedding these struc- tures and escorting them to the interior of the liver is the capsule of Glisson. The Bile Ducts (Fig. 174). These are three in number. The hepatic brings bile from the liver ; the cystic is the duct between the gall-bladder and the point where the hepatic meets it. The common duct begins at this point, passes behind the first part of the duodenum, and under the head of- the pancreas, to reach the retiring duodenal elbow, where, with the pancreatic duct, you will find it opening into the duodenum. This duct is about four inches long. The Hepatic Artery (Fig. 174). Trace this vessel to the cceliac axis. It lies, as you will see, between the two layers of the lesser omentum. Follow its 252 PRACTICAL ANATOMY. cystic artery to the gall-bladder ; its pyloric branch to meet the gastric ; its superior pancreatico-duodenal branch downward behind the duodenum ; here one branch follows the second part of the duodenum and anastomoses with the inferior pancreatico-duodenal branch of the superior mesenteric artery ; the other follows the greater curvature of the stomach and, under the name of right gastro- epiploica, anastomoses with the left gastro-epiploica, a branch of the splenic artery. Finally, trace the main branch of the hepatic artery to the transverse fissure of the liver. The portal vein lies between the common duct and the hepatic artery. (Fig. 177.) It is formed by veins from the abdominal organs of digestion. Its blood is laden with bile, glycogen, and urea. The bile is stored up in the gall-bladder ; the glycogen is stored up in the liver; the urea is thrown off. Find the hepatic veins discharging into the ascending vena cava, as this vessel passes through the diaphragm. The hepatic veins take all blood from the liver brought to that organ by the hepatic artery and portal vein. The vein discharges into the ascending vena cava, just as that vessel is passing through the diaphragm. The Greater and Lesser Peritoneal Cavities. A knowledge of these cavi- ties must be gained by study of the evolution of the peritoneum and alimentary canal, from a straight gut and single simple mesentery. (See Morris.) The foramen of Winslow connects all the cavity you can see thus far, with the lesser cavity, behind the stomach. By mechanical devices your teacher will demon- strate the modus operandi of rotation, and this demonstration will interpret the description given in the larger text. Permit me to add in this place that every organ, with all its adnexa, grows up behind peritoneum, pushes this ahead of itself, and thereby becomes invested by the same, partially or completely.' To Dissect the Duodenum. Thoroughly inflate the stomach and duodenum, as previously directed. Then divide the gastro-colic omentum and turn the transverse colon down toward the pelvis. Lift the stomach up, and observe the lesser cavity of the peritoneum behind the same. In cutting the great omentum, care must be taken not to injure the arteries along the greater curve of the stomach. (Fig. 174.) Now remove the colon from the second stage of the duo- denum. The stages of the duodenum are : (i) From the pylorus of the stomach to the gall-bladder, two inches ; (2) from the gall-bladder to the hilum of the kidney, three inches; (3) from the hilum of the kidney to the duodeno-jejunal angle, five inches. These stages are called ascending, descending, and tram verse, respectively. Relations of Transverse Duodenum. You will find, above, the superk mesenteric vessels and*the head of the pancreas; in front, the superior mesei teric vessels, the mesentery, and small intestine. Behind you will now dissec down with the forceps, and find the aorta, vena cava inferior, the crura of the diaphragm, and the fourth lumbar vertebra. On the left, the transverse duode- num terminates in the jejunum ; on the right, in the descending duodenum, the middle one-third of the kidney. The Pancreas and Splenic Artery. A very careful dissection of the pan- creas must be made. The organ is delicate. It lies behind the stomach (Fig. 180) hence turn the stomach up to expose the same. Steps : (i) Locate the splenic artery by gently lifting the upper border of the pancreas. Follow the artery to the spleen. You will now find it necessary to divide the Castro-splenic omentum, but in cloin;4 this do not injure the arteries ! Notice and save the pancreatic arteries, large and small, given to this organ the pancreas by the splenic artery. Trace out the branches given to the stomach. Find the gastro-epiploica sinistra artery. (2) Now dissect out the head of the pancreas. Trace the superior pan- creatico-duodenal artery between the pancreas and the duodenum, taking notk ABDOMEN. 253 of branches to each. Find the excretory duct of this organ the pancreatic duct opening into the duodenum with the common bile duct. The Stomach (Fig. 174). This organ has an cesophagcal opening ; a pyloric opening ; an anterior surface, on which you will find anastomosing the transverse arteries from the gastric artery and the right and left gastro-epiploic arteries ; a posterior surface, likewise occupied by arteries ; a greater curvature, occupied by the greater omentum ; a lesser curvature, occupied by the lesser omentum ; &fundus, in relation with the spleen by the gastro-splenic omentum. Now trace the gastric artery from the coeliac axis to the gastro-oesophageal junc- tion ; here you will see the artery divide into two branches one to the walls of the oesophagus, the other to the cardiac end of the stomach. The main artery follows the lesser curve of the stomach and anastomoses with the pyloric branch of the hepatic artery. The liver must be studied and dissected with reference to : 1. Lobes and their visceral impressions. 2. Fissures and their occupants. 3. Ligaments and their derivation. 4. Capsule of Glisson and its function. 5. Blood- and nerve-supply. 6. Fcetal remnants and their location. 7. The portal vein and its formation. 8. The hepatic veins and their escape. 9. The gall-bladder and bile ducts. 10. The descriptive terms used. 1 1. The relations to other structures. Lobes. (i) Right lateral; (2) left lateral; (3) quadrate; (4) caudate; (5) Spigelian. Impressions are produced by continuous contact with certain adjacent organs. On the under or visceral surface find: (i) the renal impression ; (2) the colic impression ; (3) the duodenal impression ; (4) the gastric impression. Fissures. (i) The transverse fissure is the most important. It transmits the hepatic artery, the portal vein, the hepatic ducts, and the hepatic branches of the vagus and sympathetic nerves. In front of it is the quadrate lobe ; behind it the caudate and Spigelian lobes. (2) The left longitudinal. This separates the left from the right lobes, and has an anterior and a posterior part. The anterior part contains the round ligament ; the posterior part contains the remains of the ductus venosus. (3) The fissure for the gall-bladder and (4) the fissure for the ascending vena cava. Note, too, and show on your dissection, that on the posterior sur- face of the liver are found two fissures already mentioned (a) fissure for the ductus venosus, (b} fissure for the vena cava ; while on the inferior or visceral surface are found three fissures (a) transverse, (b} umbilical for round liga- ment, (c) vesicle for the gall-bladder. (5) The right longitudinal. This also consists of an anterior branch that contains the gall-bladder and a posterior branch that contains the vena cava. The two are interrupted by the caudate lobe. Compare your dissection with figure 178. The letter H includes the five fissures of the liver in this manner : the trans- verse fissure forms the cross-bar ; the fissure for gall-bladder and fissure for vena cava form one vertical bar ; the fissure for the ductus venosus and the fissure for the round ligament form the other vertical bar. The hepatic ligaments are five in number. One of these is a. false liga- ment, a foetal remnant called the round ligament, the ligamentum teres hepatis. It occupies the anterior part of the left longitudinal fissure. The other four liga- ments are of peritoneal origin, and are called : (i) The suspensory, broad, or falci- form ; (2) the right lateral ; (3) the left lateral ; (4) the coronary. The latter 254 PRACTICAL ANATOMY. binds, as you will see, the posterior surface of the liver to the diaphragm. The lateral ligaments, which you will see on lifting the extremities of the liver, are simply outward prolongations of the coronary ligament. The liver is firmly fused with the diaphragm, a perfect appreciation of which you can only gain from study of the embryology of the alimentary canal. Vena cava BILE DUCT Portal ve; ffe.patic artery SPIGELIAN LOBE UMBILICAL FISSURE FIG. 178. THE INFERIOR SURFACE OF THE LIVKR. LEFT LOBE Vena cava SPIGELIAN LOBE FIG. 179. POSTERIOR SURFACE OF Tin I.ivi u. Glisson's Capsule. You will recall your dissection of the root-structui of the liver. Yon fouml the hepatic artery dividing into two branches, the portal vein the same, and two hepatic ilncts coming down to join the cystic; you saw nerves which are called hepatic branches from tin- vagus and sympathetic, sur rounding the hepatic artery. Now recall this: the very intimate manner r al - ABDOMEN. 255 which these structures were bound together by connective tissue. This connec- tive tissue is the capsule of Glisson the framework for the hepatic root-struc- tures. Hepatic Nerves and Arteries. The nerves reach the liver through the transverse fissure, are protected in transit by the capsule of Glisson, are dis- tributed to the substance of the liver on the branches of the portal vein and hepatic artery. These nerves come from the hepatic plexus, one of the divi- sions of the coeliac plexus. This plexus is made up of branches from the sympathetic, the right phrenic, and the left pneumogastric or vagus nerve. The nutrient artery to the liver is the hepatic. The liver receives blood for purifica- tion from all the other abdominal organs of digestion, through the portal vein ; all the blood in the liver escapes by the hepatic veins into the vena cava. To find these veins, turn the liver clown into its normal position, locate the emergence of the vena cava from the abdominal cavity through the diaphragm, and into the pericardium. Now cut through the diaphragm at this point and plow through liver substance, and you will find the hepatic veins. Another method is this : having located the vena cava above the diaphragm, cut a hole in its walls and follow the vessel downward until you see its hepatic tributaries. Foetal Remains. These are the round ligament and the ductus venosus. The former is the connective-tissue remnant of the umbilical vein, that in the foetus brought pure blood from the placenta. (Fig. 155.) This vein, on reaching the liver, broke up into three channels : (i) The greater part of the blood joined the portal vein and traversed the liver ; (2) a small amount entered the left lobe ; (3) a small quantity passed through a vessel the ductus venosus to meet the left hepatic vein, as that vessel was entering the vena cava. After the lungs became the organ of respiration, the placental circulation lost its specific character as a conduit, t The main vessel, the umbilical vein, dwindled to a mere cord the round ligament. The three termini of the vein did the same, and are known as remnants. The ductus venosus dwindled, and is consequently in the adult a fcetal remnant. The portal vein in its relation to the root-structures of the liver will be seen in figure 177. In your dissection you have found it embedded in Glisson's cap- sule, and occupying a place between the hepatic artery and common bile duct, and posterior to both. Its tributaries come from all the organs in the abdominal cavity associated, with the digestion of food, except the liver. The veins which you must demonstrate on your dissection as forming the portal vein are : (i) The superior mesenteric ; (2) the inferior mesenteric ; (3) the splenic ; (4) the gastric. Notice particularly on your dissection that three veins the gastric, splenic, and superior mesenteric come together to form the portal vein directly ; the inferior mesenteric is tributary to the splenic, hence it is not a primary, but a secondary tributary to the portal vein. The hepatic veins must be located according to the two methods given under caption of Hepatic Nerves and Arteries. (Page 253.) Having found the hepatic vein, look on its under surface for "the remains of the ductus venosus, for, you will remember, one branch of the umbilical vein in the foetus terminated here. (Fig. I55-) The gall-bladder and its system of ducts must now be carefully dissected. Any degree of rough manipulation will defeat a perfect dissection. Follow these steps : (i) Take the organ in the left hand, and with your forceps in your right carefully dissect the connective tissue, holding the gall-bladder in the cystic fissure. (2) Having now liberated the organ from its bed, and having exercised every care not to injure the vessels and ducts attached thereto, you may (3) cut a slit in the fundus of the organ, introduce a blowpipe, and inflate. (4) Have an assistant ligate as you inflate. (5) Now follow downward, and liberate from the 256 PRACTICAL ANATOMY. capsule of Glisson the ducts : hepatic (two), cystic, and common. Follow this latter, the common bile duct, three and one-half inches to its confluence with the pancreatic duct, in the receding angle of the duodenum. The descriptive terms used in speaking of the liver are : 1. The root, transverse fissure, or porta hepatis. This is where the vessels, nerves, and ducts enter, surrounded by the capsule of Glisson. 2. T/ie superior or phrenic surface is in relation to the inferior surface of the diaphragm. It is covered by peritoneum, except a small space between the two layers of the suspensory ligament. 3. The inferior or visceral surface rests on the stomach, duodenum, colic elbow, right kidney. Two places are not covered by peritoneum : the fissure in which the gall-bladder rests and the transverse fissure. Surgically, this is the most important part of the liver, and should be most faithfully studied by the student. 4. The posterior surface is a territory you can see only when you remove the liver. It is mostly uncovered by peritoneum, and is limited by the anterior and posterior layers of the coronary ligament. 5. Tlie anterior border is the one interrogated in physical examinations of the liver. It is quite thin and is marked by two notches, one for the suspensory liga- ment and one for the fundus of the gall-bladder. This latter is, in health, oppo- site the ninth costal cartilage. This border is about in line with the ribs. 6. The extremities, right and left, are associated with the lateral ligaments, but have no special importance in physical diagnosis. The hepatic elbow a coinage* will be explained when the anterior relations of the right kidney are considered. 7. Peritoneal investment of the liver is for practical purposes complete ; never- theless, on each surface we have found areas not completely covered. This has been explained under the head of peritoneum on page 238. The relation of the liver to other organs is one of the most fascinating and instructive parts of the work thus far encountered, (i) Now show on your dissection that the superior surface of the liver is related to the under surface of the diaphragm, and separated by the diaphragm from the bases of the lungs, base of the pericardium, anterior abdominal wall, and six or seven lower ribs on the right side. (2) Show that the inferior surface of the liver lies on the right kidney and its adrenal ; on the hepatic flexure of the colon ; on the descending duode- num ; on the gall-bladder and its duct ; on the root-structures of the liver; or the right end of the stomach ; on the upper curve of the duodenum ; on th< anterior surface and lesser curve of the stomach ; on the lesser omentum. Show that posteriorly the liver is in relation with the diaphragm and its crui the tenth and eleventh thoracic vertebrae and their ribs, the oesophagus, aorta, vena cava, and thoracic duct. To show these posterior relations separate the liver from the diaphragm and pull it far forward, but do not injure the vena cava you may ligate and then cut the hepatic veins. This will give you an opportu- nity to study the coronary ligament also. All the above relations are to be studied without cutting anything except possibly the hepatic vein, as above indicated. The Superior Mesenteric Artery. To make a good dissection of this artery and its branches, turn the transverse colon up and pull the mass of small intestine forming the jejunum and ileum far down over the left iliac region, as shown in figure 180. Now, remember the mesentery contains, between its two layers, all the vessels, glands, nerves, and lymphatics that go to or come from the small intestine. Remember all those struetmvs arc embedded in connective tissue, just as are the root-structures of the liver enclosed by Glisson's capsule that the function of this mesenteric connective tissue is, like Glisson's capsult protective and supportive-, and contains, in some persons, large quantities ot I. it technically designated mesenteric fat. ABDOMEN. 257 Dissection. Locate the main stems of the artery and vein as they emerge from the under border of the pancreas, gently thrust your forceps never the scalpel through the upper layer of. the mesentery, then use your fingers instead of the forceps and you can easily strip off the remainder of the peritoneum out to the intestinal margin of the mesentery. Trace out with your forceps, by removing the mesenteric connective tissue, always in the direction of the vessel, the following branches: (i) The ileocolic branch to the appendix, caecum, ascending colon, and ileum ; (2) the right colic artery to the ascending colon ; (3) the middle colic artery to the transverse colon ; (4) the main bulk of the artery to the jejunum and ileum under the name of intestinal branches or vasa Left colic artery Superior mesen- teric artery and vein Ileo-colic artery VERMIFORM APPENDiX Vasa intestini tennis SMALL INTESTINES FIG. 180. THE SUPERIOR MKSENTERIC ARTERY AND VEIN. (The colon is turned up, and the small intestines are drawn over to the left side.) intestini tenuis ; (5) a small branch already found the inferior pancreatico- duodenalis. The veins must be dissected at the same time. If now you will thoroughly wash the mesenteric fat away with ether, and permit the specimen to dry, the sympathetic nerves accompanying the arteries may be seen. The Inferior Mesenteric Artery. To dissect this artery and its accompany- ing vein, take the mass of jejunum and ileum far over to the right side. (Fig. 181.) Locate the main stem of the artery at its origin from the abdominal aorta, make a hole through the peritoneum, and, as in the dissection above described, strip off the peritoneum. Now trace out the following branches : (i) The sig- moid artery to the sigmoid flexure of the descending colon ; (2) the superior 258 PRACTICAL ANATOMY. haemorrhoidal artery to the rectum ; (3) the left colic artery to the descending colon. Summary. (i) The descending colon and rectum are supplied with blood by the inferior mesenteric artery. The blood from this area is returned by the inferior mesenteric vein, which passes behind the pancreas and is tributary to the splenic vein. (2) The remaining part of the intestinal canal, below the stomach, including the small intestine and the ascending and transverse colons, is supplied by the superior mesenteric artery. The blood from this area is collected by veins which come together to form, with the gastric and splenic veins, the portal vein. The name portal circulation is given to the veins coming from all the abdominal Middle colic artery Inferior pancreattco- duodenal artery Superior mesenteric artery Riyht colic artery A bdominal aorta - Vena cava inferior . Right common iliac _ artery Middle, sacral artery and vein I.fft colic artery JuJ'erior inrsenleric 1 1 in Inferior mrsni/i rir artery Left co/ic ttrlerii !iij< rior in i. ie liter ic artery Left common iliac i-i in Sigmoid artery Superior tiii'tiiur r/tuiilal tirlt-ry FIG. 181. THE INKKKIOK MISKN 1 1 UK- AKTKKY AND VKIN. (The colon is turned up, and the small intestines are drawn to the right side.) organs of digestion, except the liver. This blood is laden with urea, glycogen, and bile, all of which are removed from the blood in the li\vr. Anastomosis of Arteries to the Abdominal Organs of Digestion. (i) Tin- gastric artery from the cceliac axis supplies the abdominal part of the (esoph- agus, the side of the stomach represented by the lesser curve, and anastomoses with the hepatic, at the pyloric end. (2) The hepatic artery supplies the liver and communicates, through the Castro-duodenal artery, with both the splenic and superior mesenteric arteries. (3) The several branches of the mesenteries successively anastomose, so you can trace- from (esophagus to rectum the con- tinuous blood-supply to all the viscera of this system. Anterior Relations of the Right Kidney. The anterior surface of the right kidney is occupied, from the kidney forward, (i) by the anterior part of the fatty capsule ; (2) by the following organs : liver, duodenum, colon. For the ABDOMEN. 259 purpose of aiding the memory, call the visceral relation that of the three elbows : the hepatic elbow, the duodenal elbow, the colic elbow. Now demon- strate as follows : Carefully pull the hepatic flexure of the colon downward, and notice that this is made up of the upper end of the ascending and the proximal end of the transverse colon, and rests approximately on the lower third of the kidney. (Fig. 182.) Next trace down the second part of the duodenum (inflated), and see that it forms a flexure where it joins the transverse duodenum. Turn this off and call it the duodenal elbow, observing that it occupies the middle third of the kidney. Lastly, observe the anterior border of the liver come down and suddenly recede backward and upward. It covers the upper third of the anterior surface of the kidney, and forms the hepatic elbow. Notice, too, that the areas occupied by the duodenal and colic elbows have lost their peritoneum, in accordance with a law explained under the head of peri- toneum. The left kidney has two non-peritoneal areas. Anterior Relations of the Left Kidney. The first relation is the fatty cap- sule. Then the following viscera you will remove in this order : (i) The fundus DUODENAL AREA HEPATIC AREA GASTRIC AREA (NON-PERITONEAL) (NON-PERITONEAL) CAVAL AREA (PERITONEAL) DUODENAL AREA (NON-PERITONEAL) A\ PANCREATIC AREA (NON-PERITONEAL) COLIC AREA (NON-PERITONEAL) COLIC AREA OF SPLEEN COLIC AREA (NON-PERITONEAL) PERITONEAL AREA WITH RIGHT COLIC VESSELS PERITONEAL AREA WITH LEFT COLIC VESSELS FIG. 182. DIAGRAM SHOWING ANTERIOR RELATIONS OF KIDNEYS AND SUPRARENAL BODIES. of the stomach ; (2) the tail of the pancreas ; (3) the descending colon ; (4) the last part of the duodenum. Posterior Relations of Each Kidney. Carefully remove the kidney from its bed of fat and connective tissue, and turn the same to the mid-line with all its root-structures attached. Great care must be taken in handling the left one not to injure the left spermatic vein (ovarian, if a female), which discharges into the left renal vein. Then, having removed the posterior part of the fatty capsule, you will find three nerves: (i) The last thoracic; (2) the ilio-hypogastric ; (3) the ilio-lumbar. Then you will be able to make out the (i) quadratus lumborum muscle, covered by the anterior lamella of the lumbar fascia; (2) the diaphragm ; (3) the psoas magnus muscle ; and (4) the lowest intercostal artery. The Root-structures of the Kidney (Fig. 183). These are, from before back- ward, as met in your dissection : (i) The vein ; (2) the renal artery and its sym- pathetic nerves ; (3) the expansion of the ureter, known as the pelvis of the kid- ney. You will find these structures loosely bound together by connective tissue, like the capsule of Glisson or the mesenteric connective tissue. This you must divide in the direction of the structures. You will now puncture the ureter in 260 PRACTICAL ANATOMY. the region of the brim of the pelvis and inflate the same to see the beauty of the pelvis of the kidney. Descriptive Terms. The kidney has a superior and an inferior extremity ; an anterior and a posterior surface ; a strong fibrous capsule, which may be easily peeled off. The place where the nerves, vessels, and duct pass into the kidney is called the hilum. (Fig. 183.) Cut through the kidney longitudinally, from the outer to the inner border, and see the cortical and pyramidal structure of the Cystic artwy HEPATIC DUCT CYSTIC DUCT COMMON DUCT Putin/ a i ,. Gastro-duodenal br. Superior pylnrii- In Hepatic arlrri Right suprarenal mY Inferior tvpi-inrim' artery Renal artery Renal vein Inferior vena cava KIDNEY Right spermatic vei Right spermatic artery Quadratus lumborum muscle Right lumbar artery and left lumbar vein Ureteric branch of spermatic artery Middle sacral vessels LEFT LOBE OF LIVER (ESOPHAGUS Left phrenic artery Right phrenic artery Superior suprarenal Gastric artery Inferior suprarenal Splenic artery Left phrenic rein Left tuprarena: Superior meseiiteric artery KIDNEY Ureteric branch of renal Left spermatic rein URETER Left spermatic artery Inferior mesenteric artery Ureteric branch of spermatic Ureteric branch of common iliac Common iliac artery External iliac arle Internal iliac artery FIG. 183. THE ABDOMINAL AORTA AND ITS BRANCHKS, WITH TIIK INFERIOR VENA CAVA AND ITS TRIBUTARIES. kidney. Figure 613 (Morris) shows the interior of the sinus and the formation of the pelvic portion of the ureter. The ureter having been inflated, examine for one or more small urcteric arteries, branches of tin spennatic, superior vesical, and common iliac arteries on the ureter. Connected with the upper extremity of the kidney by connective tissue, find the adrenals or suprarenal capsules. These arc ductless glands. Trace out their arteries to the renal and phrenic arteries and to the aorta. ABDOMEN. 261 THE SYMPATHETIC NERVE. In the cranium, neck, thorax, abdomen, and pelvis you will have to do with arteries, nerves, viscera, and localities where the sympathetic nerve, while perhaps anatomically the smallest structure, in these localities is nevertheless the most important structure. It would be just as wanton to ignore and destroy, or, what is worse, fail to see, the hairspring of a watch, if you were taking a watch to pieces, as it would be to dissect a human body and not have a clear under- standing of the sympathetic nerve. The necessity of at least familiarity with the rudiments of this system of nerves will be apparent, when I remind you that you will hear more or less about the sympathetic nerve from every chair in your medical course. The physiological action of drugs depends on vaso-contraction and dilatation to a great extent. The rationale of the obstetrician's Crede manipulation, is stimula- tion of sympathetic uterine contraction. The physiologist invokes the sympa- thetic system when he would explain the function of viscera. The pallors and hyperaemias, the exanthemata, and the thousand and one strange phenomena in skin diseases are, to a greater or less degree, temporarily or permanently amen- able to remedies that act in some way through the sympathetic. In general and special medicine, in surgery and all its special departments, you will hear of parts played by the sympathetic nerve. Are you, then, to remain in ignorance, or are you to gain a comprehensive knowledge of this subject by intelligent dissection ? An erroneous opinion prevails among students that the sympathetic cannot be seen, on account of its smallness. No ; this is not the reason students often fail to find and become familiar with these nerves. You can see at a distance of six feet the cervical, thoracic, and abdominal ganglia, of the gangliated cord. You can see at a distance of ten feet the solar and cardiac plexuses. You can see at a distance of four feet the hypogastric plexus. You can see at a distance of two feet the communicating branches extending from one ganglion to another of the gangliated cord. You can see the greater and lesser splanchnics five feet away. At a distance of fourteen inches you can see the rami communicantes the little nerves connecting the sympathetic cord and the anterior primary divisions of the spinal nerves. At a distance of twelve inches you can see the gastric, hepatic, splenic, and mesenteric sympathetic nerves. At a distance of ten inches you can see the sympathetic nerves on the internal carotid artery in its cavernous, petrosal, or cerebral stages. You can see the Vidian nerve, the petrosal nerves, the ophthal- mic ganglion. At the closest normal visual range you can even see the sympa- thetic nerves that accompany the ovarian and uterine arteries. You can even see the long and short ciliary nerves to the eyeball. I saw a man last summer who could not see the moon through a Yerkes telescope. In this case the moon was on exhibition, and the powerful lens was in working order, but the man in question did not know where to look. So, in anatomy, the sympathetic nerve is everywhere on exhibition. Its dimensions are not great, it is true ; still, if you know where to look, you will have no diffi- culty in finding this nerve. The peculiar sympathetic lustre makes its identity certain, after you have dissected and studied this nerve a short time. The object of this chapter is to teach you where to look, to find the sympathetic nerve in all regions of the body ; to teach you how to let the nerve alone, having once found the same and this is its dissection ; to furnish you with an outline, embracing the rudiments of what is known of the sympathetic to-day and this by the following questions and their answers : I . What is a sympatJietic nerve ? Cranial and spinal nerves are collectively designated somatic nerves. These 262 PRACTICAL ANATOMY. preside over the special senses and supply muscles with motion and skin and membranes with sensation. These muscles and parts, constituting so much of the bulk of the body, depend on certain organs for air, blood, for the products of digestion ; in other words, there are certain organs in the body concerned in the preparation of nutriment for the tissues. This nutriment must be distributed n of Sites to G.ofRoot ofPneumog, taPe-trosal G. Glosso-ph. Vidian to$-P Ganglion to U.ofPne utnoycutrtc tofffpoyloaaal Jff. to br. of Ext. Carotid. A. to Pharyngeal P to Inf. Thyroid A . Cardiac br.fkPneumogast. andfiec.Laryrufeal Kcrvr CarcLiac Plexus .Coronary Plexus G.= GANGLION. P.= PLEXUS. A.-ARTERY. 1. 2.3.*. BRAN CHES. FROM PNEUMOGASTSiC NERVE TO THE CARDIAC PLEXUS. kpaticP. , ,^-f^f Cystic Gaslrvjtuadenal 4th from Couyyoal Ganglion Impar. FIG. 184. Tin SY> 5 Sup.ffemorrnoidaL 6 Spermatic Plexus. Pelvic P. orlnfHypogastric. SUPPLIES ALL THE PELVIC VISCERA AND THE PENIS. Frvm fbttsrS Compend of Anatomy. SYSTEM OF NERVES. to the tissues, at tinu-s in maximal cuiantities, at other tinu-s in minimal cjuantitics. Tin- action of the s\-mpathetic is, among other things, to dilate or contract the vessels bearing this blood, for thr nutrition of the tissues. In this sense then a feeder of organs, the sympathetic looks after the lixes of organs hence its synonym, tlu- mrve of organic life. ABDOMEN. 263 2. From where to where docs the gangliated cord extend ? From the ganglion of Ribes above, on the anterior communicating artery, to the ganglion impar below, on the coccyx. 3. Hou> many ganglia are in each region of the spine / Three in the cervical ; twelve in the dorsal ; four in the lumbar ; four in the sacral region. 4. Where will we find these ganglia in the cervical region in dissection f In the neck, behind the carotid sheath, the superior cervical ganglion ; on the inferior thyroid artery, the middle cervical ganglion ; on the inner side of the superior intercostal artery, the inferior cervical ganglion. This one is somewhat difficult to find, as it lies in fatty connective tissue. Look between the trans- verse process of the seventh cervical vertebra and the neck of the first rib, and you will find it. Dissolve the fat in ether and pack the region with a two per cent, solution of formaline, to develop well the branches of this ganglion, which branches are somewhat numerous. 5 . Where are the ganglia located in the thorax ? You will find them in fatty connective tissue, behind the pleura costalis, on the heads of the rib. These are smaller than the cervical, but easily found. 6. Where will we find the ganglia in the lumbar portion of the gangliated cord ? Along the inner margin of the psoas magnus muscle, behind the peritoneum, in fatty connective tissue. 7. Where vvill we find the ganglia in the sacral region of t/te gangliated cord? Along the inner side of the anterior sacral foramina, behind the peritoneum, in fatty connective tissue. 8 . Hcr L v are these ganglia, in the regions above mentioned, connected ? By interganglionic cords or nerves. These can all be seen, and must be demonstrated on the cadaver by the student. 9. What are the rami commnnicantes ? They are two little nerves that extend from the spinal nerve, shortly after its emergence, to the ganglia of the gangliated cord. These are the somatic com- munications referred to above. i o. How do sympathetic nerves reach the organs or parts they are destined to supply ? In two general ways : (i) The majority of sympathetic nerves travel with the artery to the organ, and take the same name as the artery. (2) Some few accompany somatic nerves to a part ; the sympathetic nerves to the pharynx accompany the vagus and glosso-pharyngeal nerves, and then take the name of the part supplied. 1 1 . Are there any important nerves given off from the superior cervical gan- glion ? If so, zv/iat arc they, and where are they distributed ? Yes ; from the ganglion are given off branches that accompany the branches of the internal carotid artery to the brain ; the ophthalmic artery to the orbit ; communicating branches to the third, fourth, fifth, and sixth cranial nerves. 1 2. What branches are given off from the middle cervical ganglion ? Nerves to all the branches of the external carotid artery ; nerves to the pharyngeal plexus ; a nerve the superior cardiac nerve. 13. What nerves are given off from the inferior cervical ganglion f From this are given off the principal nerves to the cardiac plexus. 14. Explain the sympathetic distribution from the twelve thoracic ganglia. In round numbers, the six upper are given to the cardiac plexus ; the six lower to the solar and renal plexuses, by the splanchnics. i 5. How is the hypogastric plexus formed f By branches from the lumbar and sacral parts of the gangliated cord. 1 6. What is the function of the cardiac prevertebral plexus ? 264 PRACTICAL ANATOMY. It supplies lungs and heart. It is formed by sympathetic nerves, supple- mented by filaments of the phrenic and vagus nerves. 17. How is the solar plexus formed, and to what organs arc its brandies dis- tributed.'' 1 5** Cranial tferve 2. The Orbit 3 3 rd 4^6^ Cranial tfe 4 To the Arteries of the ffraiti to (LofRoot ofPneumog. toPttrosal ff.of^ Glos.so-ph. 7o muscles concerned in respiration Cervical Plexus Somatic Pain To upper extremity Brachial Plexus Somatic Pain To Thoracic Walls 6 upper intercostals Somatic Pain To Abdominal Walls 6 lower intercostals < ; Somatic Pain Lumhar Plexus To front ofThioh anJ/fnet \ Somfi/ic Pain Sacral Plexus To posterior part ofThiah To Lea To external Genitals Somatic Pain G.'GANOLION. Cardiac br. fhPn eu-mogastric p. = p L E x u s . andRec.Larynytal Rcrves A.. ARTERY. G.ofWrisberg 'Cardiac Plexus . n ^ ffgarf ana < Lun j S 1.2.3.4. BRAN CHES. FROM PNEUMOOASTRIC NERVE TO THE CARDIAC PLEXUS. r epaticR . ; u^rf Cystic Gastrculuadenal the Abdominal Oryam S Sup.Hemorrfioidal. 6 Spermatic Plexus. > To the Pelvic 0/yans Pelvicp.orlnfflypogaslnc. SUPPLIES ALL THE PELVIC VISCERA AND THE PENIS. from Couyyoal Ganglion Impar. Fivrn'tbtterS Compend ofJlnatomu. FIG. 185. THE SYMPATHETIC SYSTEM OF NERVES. By the sympathetic, as above indicated, in union with filaments from the vagus nerves. It is distributed to the abdominal organs, exclusive of the organs in the pelvis. 1 8. To what is tlie liypogastric /Vr.ivc.v distributed / To the organs in the pelvis. It will be remembered the nerves reach organs ABDOMEN. 265 by accompanying the artery to the part. Hence it occurs that the ovary and testicle receive their nerve-supply from the renal plexus. In the subjoined figure the tendency of plexuses to supply areas below their own level will be seen. 19. Wliat is meant by automatic action in sympathetic ganglia ? The ganglia of the heart and intestine have the power of independent action ; still, the sympathetic is no longer considered a separate system. 20. Is there any definite means of judging of the location of disease founded on the nature or location of pain ? Or, conversely, may pain incident to disease of the various organs in the three great cavities thorax, abdomen, and pelvis be ration- ally accounted for in the distribution of cerebro-spinal or somatic nerves ? Yes ; for, as the following pages will show, somatic nerves often report pain that has its origin in an organ far away from the origin. These somatic nerves also transmit both pain and motion more rapidly. For an example, in valvular lesion the pain in the chest behind the sternum, so long as reported by the sympathetic nerve to the patient as a subjective symptom of disease, is constant and aching. When, however, the case assumes a grave aspect, and the pain is reported to the patient's sensibility by the somatic nerves, then an aching pain is replaced by one described as darting and stabbing. Then, too, the location of the pain will have changed. The aching sympathetic pain behind the sternum is now felt in the little and ring fingers. Consult the characters of sympathetic and somatic pain in the following paragraphs. Con- sult figure 185 and see : (i) The heart is supplied by sympathetic nerves by the cardiac plexus ; (2) the sympathetic nerves forming the cardiac plexus com- municate with the somatic nerves in the area where are given off the nerves forming the brachial plexus ; (3) as sensory nerves report pain peripherally, we may logically account for the digital pain in valvular lesions in the distri- bution of the brachial plexus in general, or in the specific distribution of the ulnar nerve in particular. The same is true of all diseases of viscera in which pain figures conspicuously as a subjective symptom. To find the possible somatic area where pain may occur, use figure 185 according to the following steps : (a) Where is the diseased organ located ? (V) Are the organs in this area supplied by the cardiac, solar, or hypogastric plexus ? (. Cardiac Plexus X -X Heart -X Arm, Finyers, Shoulder and Abdominal Wall* Cardiac Plexus L n y -X- Pneumonia 1 Pain in Lumbar ret/ton 2 Pain in the Kpigasfrum .? Pain on the sound side Pelvic Plexus ^^- Ovaritis x x Patella I Motor of Anterior Crural > ^^^^ Motor t/ie 7?A ,. X face FIG. 187. SHOWING SCHEMATICALLY A MOTOR REFLEX CIRCUIT. 2. This plexus, which always takes the name of the artery it accompanies, has its origin in a ganglion near the beginning of the artery on the aorta ; the plexus also takes the name of the artery which its branches accompany. 3. The ganglion /. e., all the ganglia situated at the beginning of all the branches of the abdominal aorta is fed by nerves from the solar plexus. 4. The solar plexus is situated in front of the beginning of the abdominal aorta. It consists of two large semilunar ganglia, which embrace the co-liac axis. The two ganglia are connected both above and below the artery which they embrace. The plexus is formed by branches from the vagus, uniting here with the sympathetic. In this way, then, may be explained the manner in which the vagus reaches all the abdominal organs with motor fibres. 5. The solar plexus, then, is that part of the sympathetic nerve from which all the abdominal viscera derive their nerve-supply. It is situated high, but is prolonged downward under the name of the aortic plexus. From this the gan- glia situated at the beginning of the branches of the aorta take their origin ; these ganglia throw off plexuses which accompany the artery. The solar plexus is a sort of clearing-house for the abdominal sympathetic nerves. 6. From above down, then, the succession of names is as follows : (i) '1 he solar plexus, formed of two semilunar ganglia; (2) the dowmvard prolong- ABDOMEN. 271 tion of the solar plexus, called aortic plexus ; (3) ganglia situated at the origin of every artery from the aorta, which take the name of the aorta ; (4) branches or plexuses from the ganglia, which take also the name of the artery and accom- pany the same to its distribution. In view of the foregoing, you are prepared now to find, locate, explain, and understand : 1. Diaphragmatic artery, nerves, plexus, ganglion, and vein. 2. Splenic artery, nerves, plexus, ganglion, and vein. 3. Hepatic artery, nerves, plexus, ganglion, and vein. 4. Gastric artery, nerves, plexus, ganglion, and vein. 5. Suprarenal artery, nerves, plexus, ganglion, and vein. 6. Renal artery, nerves, plexus, ganglion, and vein. 7. Spermatic artery, nerves, plexus, ganglion, and vein. 8. Ovarian artery, nerves, plexus, ganglion, and vein. 9. Superior mesenteric artery, nerves, plexus, ganglion, and vein. 10. Inferior mesenteric artery, nerves, plexus, ganglion, and vein. Dissection of the above nerves requires care. Work in the direction of the Aorta SOLAR PLEXUS, THE ABDOMINAL CLEARING-HOUSE FOR THE SYMPATHETIC NERVE c artery, large SYMPATHETIC NERVE, CALLED MESENTERIC A MESENTERIC GANGLION ON THE AORTA FIG. 1 88. To SHOW RELATION OF ABDOMINAL SYMPATHETIC NERVES TO (i) SOLAR PLEXUS AND (2\ TO THE GANGLION AT THE R()OT OF THE ARTERY. vessel, with forceps. Consult the figures heretofore given to find name and location of vessels. For solar and aortic plexuses see figure 186. Make special note : (i) The renal veins lie in front of their arteries, thereby forming an exception to the rule governing the relation of arteries to veins. (2) The left spermatic vein opens into the left renal vein, and this latter passes in front of the aorta. (3) The right spermatic vein opens into the ascending vena cava just below the renal. (4) The ovarian veins follow the course of their homologues. (5) The spermatic arteries arise from the aorta below the renals, pass in front of the ureter about opposite the bifurcation of the aorta. The ovarian take the same course. (6) The four lumbar arteries are analogous to the intercostals. (7) The ureteric arteries accompany the ureters ; they are branches of the common iliac and superior vesicle. (8) The arteries to the vas deferens, to the urachus, and to the ureter are branches of the superior vesicle. (9) The sacra media, the smallest. Essential Points on the Sympathetic. You have traced out the branches of the abdominal aorta, and I trust you now understand the principle under- lying the distribution of visceral nerve-branches, from one abdominal prevertebral plexus the solar plexus. We shall find in the pelvis, likewise, organs receiving arteries ; these arteries will be accompanied by sympathetic nerves ; these nerves 272 PRACTICAL ANATOMY. GANGLION DIAPHRA GM. I IK 7 M/ SUPRARENAL CAPSULE ORE A T 8 PL A NCH- NIC NER VE RIGHT SEMI LU- NAR GANGLION RENAL GANGLION SMALL SPLANCHNIC NERVE Renal artery GANGLIA TED CORD RAMUS COMMUNICANT Hepatic artery BRANCH TO AORTIC PLEXUS LEFT SEMI LU- NAR GANGLION (iHF.AT -V/r NJ- SMA LL SI'LA S< 'II- Superior mesenteric artei-y RENAL GANGLION Renal artery SUPERIOR MESENTERIC GANGLION BRANCH TO AORTIC PLEXUS GANGLIA TED CORD OF SYMPA THETIC Inferior mesenteric artery INFERIOR .V/'N/'.v- TERIC GANGLION Disc between last lumbar and first sacral vertebra ('mil until ilinc rt in Common iliac artei-y IMC. I.S CORD, WITH Till. Soi.AK AM' I I V l'( )CAS IK U I'l.KXCSKS. (I It-Ill.', i ABDOMEN. 273 will come from plexuses on the artery ; these plexuses will originate in ganglia near the origin of the artery ; they will take the name of the artery and trace their own origin to the hypogastric plexus. We shall find, in the thorax, the heart and lung concerned in the circulation of the blood and its purification respectively. These organs receive their nourishment through arteries, and their arteries are attended by nerves, which nerves have their origin in plexuses ; these plexuses spring from ganglia near the origin of the artery, and these ganglia trace their own origin to the cardiac plexus. There is, then, one great sympathetic depot for the organs in the thorax, called cardiac pie. rus ; one in the abdomen, called solar plexus ; one in the pelvis, called hypogastric plexus. This arrangement is simply to make possible a physiological division of labor. Remember, then : the manner of distribution of sympathetic nerves is always the same in every region of the body ; branches, plexuses, and ganglia take the name of the artery ; there are three large plexuses (i) cardiac, (2) solar, (3) hypogastric ; there are as many small plexuses as there are arteries to supply viscera and these small plexuses all draw their influence from the three large plexuses. In view of what we have found, and what we shall find, let us gain a general idea of the sympathetic system in the following questions and answers : 1. Is the sympathetic a system, separate and entire, and independent of the ccrebro-spinal ? No ; sympathetic nerves are only nerves, branches of the spinals, set aside to supply organs. 2. Of ivhat docs ttic sympathetic system consist f (i) Of gangliated cord, in the form of a horse-collar, communicating on the anterior communicating artery above and on the coccyx below ; (2) of spinal branches, called rami communicantes two from each spinal nerve ; (3) of three prevertebral plexuses cardiac, solar, and hypogastric ; (4) of branches of distri- bution ; (5) of plexuses and ganglia that take the name of the arteries on which found. 3 . Can iv e see the nerves and ganglia / Yes ; in the thorax behind the pleura, and located opposite the heads of the ribs, you can seethe ganglia ; you can also find the two communicating branches from the spinal nerves ; also the cord extending from one nerve to another. The Hypogastric Plexus. In the lumbar region you will find the gangli- ated cord on the front of the bodies of the vertebrae, along the inner margin of the psoas magnus. You can trace branches to the lumbar nerves behind the psoas magnus. You will see numerous branches from the lumbar cords, uniting with branches coming down from above to form the hypogastric plexus. This is between the common iliac arteries and passes down to form the pelvic plexus. THE PELVIS. DISSECTION OF THE PELVIS. Inspect and become familiar with the following : 1. The pelvic contents are covered by peritoneum. 2. The rectum is on the posterior wall of the pelvis. 3. The bladder is on the anterior wall of the pelvis. 4. The obturator nerve and vessels are on the outer wall. 5 . The ureter crosses into the pelvis and can be seen. 6. The uterus and adnexa are between bladder and rectum. 7. The broad ligament contains the uterine adnexa. 8. The recto-vesical poucli is between the rectum and bladder. 9. The peritoneum does not cover the anterior surface of bladder. 10. Retzius' space is between bladder and pubes. 1 1. The recto-vaginal, recto-uterine, and cul-de-sac of Douglas. 12. Douglas' cid-de-sac is between the rectum and vagina and uterus. 13. Ilciun and great ojnentum gravitate into the pelvis. Follow this order in your dissection : 1 . The peritoneal ligaments of the bladder, rectum, and uterus, and the sympathetic nerves from the pelvic part of the hypogastric plexus to the same viscera, noticing they invariably follow the arteries to the organ, and take the name of the artery. 2. The pelvic fascia and its subdivisions and modifications incident to use, remembering, as you must, that growth is the correlative of function. Notice, too, that pelvic fascia is condensed subperitoneal connective tissue. The upper or uncondensed portions of the pelvic fascia contain fat. 3. Study the relations of the psoas carefully ; as nearly as may be, follow the steps just as given in the sequel, for this is the order in which you will meet all these various structures in your dissection. 4. The lumbar plexus ; its location in the substance of the psoas muscle ; its formation by the four upper lumbar nerves and a communicating branch from the twelfth thoracic ; and its immense distribution. .5. The internal iliac artery and all its branches, where the same escape froi the pelvis, the spinal nerves they accompany, and the source of the sympathetic nerves that encircle them to supply the viscera. 6. A view of the ischio-rectal fossa from above, by cutting the origin of the levator ani muscle at the white line and looking in on the obturator interims muscle that forms its outer wall. 7. The sacral plexus, its location, relations, communications, and branches distribution, and where these large branches escape from the pelvis. 8. In addition to the above, make dissection and study of the iliacus (origin of), the pyriformis, the levator ani, the obturator interims, the white line of the pelvis, and the delamination in the obturator fascia, called Alcock's canal. In order to estimate the peritoneal ligaments in any peritoneal region, asl yourself how many viscera of considerable size grew up behind this membram 274 THE PELVIS. 275 and pushed the same before themselves. In the pelvis, the bladder, rectum, and uterus grew up and developed behind the peritoneum ; hence, not only are these three structures behind the peritoneum, but all their adnexal parts as well ; they are held in position more or less by the peritoneum, and those processes having one end on the organ and the other fixed to a wall are called the peritoneal ligaments of these organs. Inflate the bladder, and see, posteriorly, two folds extending from the rectum to the bladder ; also a fold on each side from the iliac fossa to the side of the bladder. The plica urachi is the superior ligament of the bladder. The peritoneal ligaments of the bladder are tivo posterior, two lateral^ and one superior. The Rectum. -The rectum begins at the pelvic brim, opposite the left sacro- iliac synchondrosis. You will ligate and cut the same at this point, leaving the sigmoid in situ. Notice that the upper part of the rectum has a fold of peri- toneum the meso-rectum. The next stage of the rectum is partially covered by peritoneum, like the descending colon. The lower part of the rectum, one and one-half inches in length, and extending from the tip of the coccyx to the anus, has no peritoneum, as you will see on the cadaver. Now search beside the rectum and bladder and you will find the pelvic plexus of sympathetic nerves, which supplies all the viscera in the pelvis. Here, as elsewhere, the nerves accompany the arteries to the parts and take the same name. The pelvic fascia is the lower condensed layer of the subperitoneal connec- tive tissue. It takes the following different names : iliac, obturator, recto-vesical,. pubo-prostatic, anal, white line, Alcock's canal according to its location. The white line you will see extending from the ischial spine to the pubic bone, one inch below the subpubic arch. It is a split in the obturator fascia, from which split arises the levator ani muscle. (Fig. 192.) The anal fascia covers the under surface of the levator ani muscle. The recto-vesical fascia extends across the upper surface of the levator ani muscle, investing the rectum and bladder. It also extends from the pubes to the neck of the bladder and prostate, under the name of pubo-prostatic. Demonstrate all these on the cadaver. The iliac fascia covers the iliacus muscle, passes out of the pelvis behind the femoral vessels, and unites with the transversalis fascia by the side of the femoral vessels to form the femoral sheath, as described on page 235. The obturator fascia covers the obturator internus muscle and delaminates to form the wJiite line. (Fig. 192.) Relations of the Psoas Magnus Muscle. (i) Lying on the muscle you see the psoas parvus ; (2) to the outer side, see the iliacus muscle and the anterior crural nerve ; (3) to the inner side, skirting the pelvic brim, the common and exter- nal iliac arteries are seen ; (4) to the inner side, and one-half of an inch below the pelvic brim, see the obturator nerve and vessels ; (5) emerging from the front sur- face of the middle third of the muscle, see the external cutaneous nerve ; (6) to the inner side, between the muscle and the common iliac artery, see the genito- crural nerve ; (7) to the outer side of the muscle, above, see the last thoracic, the ilio-kv pogastric , and the ilio-fnguinal nerves ; (8) in the substance of the muscle, this having been detached and removed piecemeal with the forceps from within outward, see the lumbar plexus, giving off the following branches. Branches of the Lumbar Plexus (Fig. 190). Dissection : 1. I lio-Jiy pogastric, to the skin over the gluteus maximus and over the hypo- gastrium ; lies between the internal oblique and transversalis ; communicates with the last dorsal. The hypogastric branch pierces the aponeurosis of the external oblique muscle one inch above the external abdominal ring, and is dis- tributed to the skin over the region of the bladder. 2. Ilio-inguinal, crosses the quadratus and iliac muscles, pierces the trans- versalis, lies between the internal oblique and transversalis, supplies the internal 276 PRACTICAL ANATOMY. oblique, lies in front ot the spermatic cord in the inguinal canal, escapes by the external abdominal ring, and supplies the scrotum and inner side of the thigh. 3. Gcnito-erural, descends on the front surface of the psoas magnus, divides into a genital and a crural branch ; the genital branch enters the internal abdom- inal ring, lies behind the spermatic cord, and is distributed to the cremaster mus- cle. In the female it goes with the round ligament, supplies the same with motion, and is lost in the labia majora. 4. The crural branch of this nerve descends on the external iliac artery, lies in the femoral sheath, and is distributed to the skin covering the insertion of the psoas according to Hilton's law. GANGLIATED CORD OF SYMPATHETIC LAST THORACIC NERVE FIRST LUMBAR ILIO- HYPOGASTRIC ILIO-INGUINAL SECOND LUMBAR FOURTH LUMBAR ILIO-INGUINAL EXTERNAL CUTANEOUS GENITO-CRURAL LUMBO-SACRAL CORD ANTERIOR CRURAL OBTURATOR OBNTTAl. BRANCH OF OEXITO-CRURAL CRURAL BRANCH OP GEXITO-CRURAL ILIO-INGUINAL DISTRIBU- TION OF EXTERNAL CUTANEOUS CRURAL BRANCH OF GENITO- CRURAL AORTIC PLEAT* LAST THORA CIC NER VE ILIO-HYPO- QA8ZRIC INGUINAL THIRD LUMBAR GENITO- CRURAL EXTERN A L CUTANEOUS GENITAL BRANCH OF GENITO- CRURAL CRURAL HKA.\CH OF (i KM Til CRUMAL ourr- RATOl FIG. 190. BRANCHES OK TIIK I,t MI.AR AND SACRAL PLEXUS, VIIAVKK i ROM BEFORE, (After Hirschfeld and Leveilte.J 5. External cutaneous, emerges from the outer side ot psoas, crosses iliacus under the iliac fascia, leaves pelvis under crural arch, below anterior superior spine of ilium, pierces deep fascia of thigh, and supplies skin over outer side of thigh, being a dismembered branch of the anterior crural nerve, in reality. 6. Obturator, emerges from psoas on inner side, lies on outer wall of pelvi leaves pelvis by obturator foramen, divides into .anterior and posterior divisions, separated by the adductor brevis muscle ; the anterior division communicates with the internal cutaneous and long saphcnous nerves, forming the subsartori plexus for the supply of the skin over the insertion of the adductors llilto 01 ,. THE PELVIS. 277 laic. It then supplies the gracilis, adductor longus, adductor brevis, and sar- torius. The posterior division supplies the hip, knee, obturator externus, and ad- ductor magnus. 7. Accessory obturator often absent ; when present it lies to the inner side of the psoas, passes under outer border of pectineus, supplying this muscle and the hip-joint. Common iliac artery SYMPA THE TIC NER YE Middle sacral artery \ Common iliac vein URETER Internal iliac artery External iliac vein External iliac artery Posterior branch of internal iliac dividing into gluteal lc.\ v/.v is formed by the union of the lumbo-sacral cord and the anterior primary divisions of the first, second, third, and a part of the fourth sacral nerves. THE PELVIS. 281 9. This union is called s"acral plexus to the lower margin of the greater sacro- sciatic foramen, where it continues its course under the name of great sciatic nerve.. 10. The sacral nerves all send rami communicantes to the pelvic sympathetic plexus, which you have already found, located to the inner side of the anterior sacral foramina, by the side of the rectum and bladder. Dissection : (i) Trace the first, second, and third sacral nerves as far into the sacral foramina as possible. Notice ! This must be done with a blunt forceps, Hit" Dura mater of . LAST TIIORA CIC NER VE ILIO- HYPOGASTRIC 77,70- INGU1NAL ILIAC BRANCH OF 1LIO- HYl'OGASTRIC Gluteus medius Gluteal artery SUPERIOR GLUTEAL NERVE ORE A T SCIA TIC NER VE INFERIOR GLUTEAL NER VE SMALL SCIA TIC NER VE POSTERIOR PHI1UAHF DIVISION GENITO-CRURAL GAUD A EQUINA Pilum terminate EXTERNAL \\ CUTANEOUS OBTURATOR Lr.MIto- SACRAL CORD -, FIRST 8 A CRA L NER VE FIFTH SACRAL NER VE VISCERAL BRANCHES Si'inlii- itrlery Small sacro-sciatic ligament PUDIC NER VE NERVE TO OBTURA TOR INTERNUS PER FORA TING CUTANEOUS OF SECOND A ND THIRD SACRAL NERVES FIG. 194. A DISSECTION OF THE LUMBAR AND SACRAL PLEXUSES, FROM BEHIND. (The anterior crural nerve is placed between the external cutaneous and obturator nerves.) and with a very delicate touch, to avoid injuring the small branches given off to the sympathetic pelvic part of the gangliated cord. After this is done, all the fat must be dissolved by ether, benzene, or gasoline. (2) Now dissect in the direction of the branches given off, and find the following : BRANCHES OF THE SACRAL PLEXUS. i. Tlic lumbo-sacral cord is the communication between the sacral and lum- bar plexuses. 19 It is formed by the fifth lumbar and part of the fourth lumbar 282 PRACTICAL ANATOMY. anterior primary divisions. This must now be located on the ala of the sacrum as it passes down into the pelvis, and its union with the first, second, and third sacral nerves carefully shown. 2. Muscular brandies to the pyriformis, the quadratus femoris, the gemellus superior, the gemellus inferior, and the obturator interims muscles. Notice ! You will find the branch to the obturator internus, leaving the pelvis by the greater and reentering by the lesser sacro-sciatic foramen. When you dissect the structures in the lesser sacro-sciatic foramen, you will find this nerve with the internal pudic structures. The nerve to the quadratus femoris and gemellus inferior leaves the pelvis by the greater sacro-sciatic foramen, and supplies a branch to the hip-joint as well. . You will trace the superior gluteai nerve through the greater sacro-sciatic foramen, above the pyriformis muscle, to the gluteus medius, gluteus minimus, and tensor vaginae femoris. The skin covering these muscles is not sup- plied by this nerve -trunk apparently, but by the ilio-hypogastric and lumbar cutaneous branches from posterior primary divisions. Now, let me impress on the student this fact : A nerve-trunk supplying a muscle must supply the skin covering the muscle, or the serous membrane under the muscle, it any serous membrane be present, and the joint moved by the muscle. The skin branches, in the majority of cases, are given off directly from the nerve- trunk, and are easily found. In a minority of cases, however, the skin branch is not given off directly, but comes from apparently another source ; to such cases as these I see no impropriety in applying the terms divorced, dismembered, or erratic. Confirmatory instances of divorced skin branches are to be found in the small sciatic, the dismembered cutaneous branch of the great sciatic, supplying the skin covering the muscles supplied with motion by the great sciatic nerve ; in the external cutaneous nerve, on the outer part of the thigh, this nerve being divorced from its parent stem, the anterior crural ; in the long pudendal nerve, or nerve of Soemmering, the dismembered branch of the internal pudic nerve, following, in- deed, a most erratic course, ensconced in the sheath of the small sciatic nerve ; in the descendens hypoglossi, a divorced branch of the cervical plexus. In view of the occurrence of anomalies, then, you are to ask yourselves, when dissecting mixed nerves : Have I found (i) muscular branches, (2) cutaneous branches, (3) articular branches ? and (4) are the cutaneous branches direct descendants of tin nerve -trunk, or are they divorced therefrom ? 3. The inferior gluten! nerve leaves the pelvis by the greater sacro-sciati( foramen below the pyriformis muscle and supplies the gluteus maximus. 4. The perforating cutaneous nerve will be found when you dissect the region, coming through the greater sacro-sciatic ligament to supply the skin ii this region. 5. The internal pudic nerve is remarkable for the great number of important areas in which it and its branches are found. It leaves the pelvis by the greater sacro-sciatic foramen below the pyriformis muscle, crosses the ischial spine, reen- ters the pelvis by the lesser sacro-sciatic foramen, here enters Alcock's canal, in the outer \vall of the ischio-rectal fossa, then pierces the triangular ligament, passes through the deep perineal space, again pierces the triangular ligament, passes through the suspensory ligament of the penis to gain the dorsum of this organ. In its course 'it throws off the following branches : As the nerve is entering the canal Alcock's it gives off the inferior lieinorrlioulal and tin prrincal branches. These pass through the fat-bearing ischio-rectal fossa. Th< inferior hemorrhoidal nerve is distributed to the external sphincter ani mnsclt and the skin covering the same. The perineal branch is distributed to the accele- rator tirin;e, transvcrsus perin.ei. erector penis, levator ani, compressor urethra, and to the skin covering the scrotum and petineum. The internal pudic nerve THE PELVIS. 283 now continues its course in Alcock's canal, and through the deep triangular peri- neal space, under the name of dorsal nerve of the penis, to which, with the sym- pathetic from the pelvic plexus, it is distributed. 6. The small sciatic leaves the pelvis by the greater sacro-sciatic foramen below the pyriformis, and breaks up into four principal cutaneous branches ascending, descending, external, and internal. The largest of the internal branches crosses the tuberosity of the ischium, and is distributed to the labia majora under the name of inferior pudendal, or nerve of Soemmering. 7. The great sciatic nerve takes its name at the lower border of the greater sacro-sciatic foramen, through which you see it leaving the pelvis below the pyri- formis muscle. Examine closely and you can see some very small branches. These are articular to the hip-joint. Lower down are given off muscular branches to the biceps semitendinosus, semimembranosus, and adductor magnus muscles. As a rule, the nerve divides six inches above the knee into the internal and external popliteal nerves. Branches of the Internal Popliteal Nerve of Great Sciatic : 1. The communicans tibialis to the communicans fibularis, a branch of the external popliteal to form by this union the short saphenous nerve. This nerve supplies the skin over the superficial group of muscles of the leg. 2. Articular- branches to the knee, with the articular arteries, superior and inferior internal, and the azygos. 3. Muscular branches to the gastrocnemius, soleus, plantaris, and popliteus. 4. Posterior tibial, which gives off an articular branch to the ankle ; a plantar cutaneous branch to the heel and sole of foot on the inner side ; muscular branches to the flexor longus digitorum, tibialis posticus, flexor longus hallucis ; a communicating branch to the soleus muscle. 5. The internal plantar, which gives off articular branches to the tarsus and metatarsus, digital cutaneous branches to the four lesser toes, muscular branches to the abductor hallucis, flexor brevis digitorum, flexor brevis hallucis, and the two tibial lumbricales. 6. Extei'nal plantar, that supplies one and one-half toes cutaneously ; mus- cular branches to flexor accessorius, abductor minimi digiti, the two outer lumbri- cales, the adductor hallucis obliquus, the adductor hallucis transversus, the flexor brevis minimi digiti, and all the interossei muscles. Branches of the External Popliteal of Great Sciatic : 1. The communicans fibularis to the communicans tibialis to form the short saphenous nerve. 2. Three articular branches to the knee, proceeding with the superior and inferior external articular arteries and the azygos. 3. Cutaneous brandies to the skin covering the peronei muscles, being given off with the communicans fibularis. 4. The anterior tibial nerve, which gives off an articular branch to the ankle, to the metatarso-phalangeal joints of all the toes. Muscular brandies to the tibialis anticus, extensor proprius hallucis, extensor longus digitorum, extensor brevis digitorum, and a muscular branch to the first interosseous muscle. 5. The musculo-cutancoiis, which gives off its muscular branches to the peroneus longus and peroneus brevis muscles. Cutaneous branches, internal and external, to the dorsum of the foot, communicating with the internal and external saphenous nerves. 1 . Where is the lumbar plexus located f It is behind the peritoneum in the deep substance of the psoas magnus muscle. 2. How is tlie lumbar plexus formed / By the union of the anterior primary divisions of the first, second, third, and a part of the fourth lumbar nerves, and the dorsi-lumbar cord. 284 PRACTICAL ANATOMY. 3. \Vitli what docs tlic lumbar plexus communicate .' (l) With the twelftli thoracic nerve, by a branch named the dor.si lumbar ; (2) with the sacral plexus, by a branch called the lumbo-sacral cord ; (3) with the lumbar part of the gangliated cord, by branches called rami communicantes. 4. Describe the sympathetic connection, and tell Juw to conduct a dissection of the same in tins region. The lumbar part of the gangliated cord is quite easily found ; the communi- cations with the anterior primary divisions of the lumbar nerves are not difficult to trace out. The double chain of the sympathetic cord consists of four ganglia on each side ; these ganglia are : (l) Right, which lie behind the ascending vena cava ; (2) left, which lie behind and slightly external to the aorta. Find the cord communicating above with the thoracic, and below with the pelvic portion, by continuity. The rami communicantes are quite long in this region ; as a rule, they are two in number, and they accompany the lumbar arteries. The lumbar arteries, then, are your guide in tracing the relation between the lumbar plexus of somatic nerves, and the lumbar part of the sympathetic gangliated cord. 5. Name the branches of the lumbar plexus. The ilio-hypogastric, ilio-inguinal, genito-crural, external cutaneous, anterior crural, obturator, accessory obturator, muscular branches to the psoas magnus and quadratus lumborum, and the lumbar element of the lumbo-sacral cord. 6. Give formation and location of the lumbo-sacral cord. It is formed by the union of the fifth lumbar nerve and a part of the fourth. In practical anatomy you find it buried, in a considerable quantity of fatty con- nective tissue behind the peritoneum, on the ala of the sacrum. This cord gives origin to the superior gluteal nerve, described previously. 7. Describe the genito-cniral nerve, and give its practical importance in diagnosis. The nerve arises from the first and second lumbar nerves. It lies on the psoas magnus muscle in the lower part of its course. It divides into: (i) A genital branch, which follows the spermatic vessels and supplies the cremaster muscle with motion. In practical anatomy you find this branch behind the spermatic cord. (2) A cutaneous branch, the crural, which is distributed to the skin of the upper inner part of the thigh. The cremasteric reflex depends on this nerve. Irritate the skin of the thigh corresponding to the sensory distribution of this, the genito- crural nerve, and the testicle of the corresponding side will be elevated by the contraction of the cremaster muscle. In diagnosis, the movement of the testicle thus produced argues in favor of the integrity of the spinal cord between the first and second lumbar nerves. In the female this nerve is rudimentary, and, there being no cremaster in this sex, the genital branch of the nerve is distributed tc the round ligament of the uterus ; the crural branch is distributed as in the male. The reflex phenomena in the female are recorded as a twitching of the external oblique ; still, I think careful observation would prove such record erroneous. Th< twitching must be in the round ligament of the uterus, since this is the homo- logue of the spermatic cord. 8. Describe a patellar reflex circuit and give its importance in diagnosis. The anterior crural nerve is concerned in this reflex. Sensory branches from this nerve, distributed over the insertion of the quadriceps, forming the plexus patella-, convey sensation to a transfer centre ; and motor branches from the anterior crural induce contraction of the extensor group of muscles on the fronl of the thigh. flu's reflex movement is normal in health. It is absent in loco- motor ataxia and in the case of lesions and diseases affecting the anterior gray cornua of the spinal cord. It is increased after epileptic sei/ures, in spinal irrit- ability, tumors of the brain and disease-^ <>f the lateral tracts of the cord, and in lateral and c vivbro-spinal sclerosis. THJ'. PELVIS. 285 9. Explain tJic tecJinicjue of obtaining knee-jerk, or patcllar reflex movement. (i) Place the patient in the sitting posture on the table, with his legs hanging at right angles to the thighs ; (2) blindfold the patient, and do not acquaint him with the procedure ; otherwise, through nerve-influence from the obturator to the sartorious muscle, phenomena of a voluntary nature on the part of the patient might be observed which would cloud your diagnosis ; (3) tap the ligamentum patellae with a ferrule, or, better still, gently prick the skin over the same with a sharp instrument. Students should be encouraged to practice obtaining these reflexes on one another. DIAPHRAGM. (Fie. 195.) Function. Partition between thorax and abdomen. Superior Serous Relations. Pericardium and pleurae. Inferior Serous Relations. The diaphragmatic peritoneum. Structure. A musculo-membranous sheet. Apertures. CEsophageal, aortic, and caval. Ligamentum arcuatum inter tiiun, part of iliac fascia. Ligamentum arcuatum cxternum, part of lumbar fascia. Central tendon forms the summit of the dome. CEsophageal opening transmits oesophagus and vagus nerves. Aortic opening transmits aorta and thoracic duct. Caval opening transmits the ascending vena cava. Physiological Action. Deepens the chest. Nerve-supply. The two phrenics and the sympathetic. Source of Sympathetic Nerve-supply. Solar plexus. Blood-supply. The phrenic arteries. Source of Plirenic Arteries. Aorta, renals, and intercostals. Hoiv many origins lias the diaphragm ? 1. Anterior or Sternal Portion. The lower border and back of the ensiform cartilage and the adjacent part of the back of the anterior aponeurosis of the transversalis abdominis. 2. Lateral or Costal Portion. The lower border and inner surface of the cartilages of the six lower ribs, and sometimes also from the adjacent part ot the ribs. 3. Posterior or Vertebral Portion. (i) The ligamentum arcuatum externum, a fibrous thickening of the anterior layer of the lumbar fascia, which stretches from the tip of the transverse process of the second lumbar vertebra to the tip of the last rib ; (2) the ligamentum arcuatum internum a fibrous thickening of the iliac fascia, which arches over the upper part of the psoas from the sick- of the body of the second lumbar vertebra to the tip of its transverse process ; (3) the cms of the diaphragm a strong vertical band, fleshy externally, tendinous internally, arising on the right side from the front of the bodies of the first to the third or fourth lumbar vertebra;:, from the intervening vertebral discs, and the anterior common ligament ; on the left side, from the bodies of the first to the second or third vertebrae only, as well as the discs and anterior common ligament. Insertion. The front, sides, and back of the central tendon. The crura are perforated, and transmit structures as follows : The right, the sympathetic and the splanchnics of the right side; the left, the splanchnics of the left side and the vena azygos minor. 286 PRACTICAL ANATOMY. Visceral Relations. On careful dissection you will see the diaphragm bears very important relations to the following structures : (i) As previously indicated, the superior surface of the diaphragm is occupied by the three serous membranes. The pulmonary surface of the diaphragm corresponds to the base of the lung. The cardiac surface corresponds to the base of the pericardium. (2) The liver, stomach, spleen, kidneys, and suprarenal capsules are in relation with its under surface. (3) The aorta, oesophagus, ascending vena cava, the vena azvgos minor, the pucumogastric nerves, the splancJmics, the sympathetic all pass through the diaphragm. (4) Posteriorly, the diaphragm arches over the psoas magnus and the quadratus lumborum. A fibrous arch, formed by the iliac fascia, arches over the psoas ; one formed by the anterior layer of the lumbar fascia arches over the quadratus lumborum muscle. Consult carefully figure 195. Lastly, remove the peritoneal covering of the diaphragm, and see the beautiful manner in which the fibers from the three different sources of origin approach for insertion the Sternal origin Opening for vena cava inferior Right division of tendon Aorta - -i Bight crus Psoas parvus Psoas Transversalis abdominia Middle division of tendon (Esophagus Left division of tendon '.- Costal origin Ligamentum arouatum internum Left crus Ligamentum arcuatum externum Transverse process of second lumbar vertebra Fourth lumbar vertebra FIG. 195. DIAPHRAGM. central tendon. The central tendon corresponds to the base of the pericardium ; the fibrous part of the pericardium is the downward prolongation and expansioi of the third layer of the deep cervical fascia, having firm bony attachments to the base of the skull ; hence, in deep inspiration it is not the central tendon that becomes depressed, but the muscular part of tlie diapliragm. I Dissection of Av/> Muscles and otlicr Structures of tlic Pelvis. (i) The quad- ratus lumborum ; (2) psoas parvus ; (3) psoas magnus ; (4) iliacus ; (5) crura o diaphragm ; (6) anterior common ligament of vertebral column ; (7) obturator interims ; (8) obturator extern us ; (9) obturator membrane; (10) pyriformis (i i) coccygeus ; (12) levator ani ; (13) white line of the obturator fascia. THE PELVIS. 287 Locate on your cadaver: (i) The iliac fossa; (2) the auricular surface of the ilium ; (3) the tuberosity of the ilium ; (4) the tuberosity of the ischium ; (5) the spine of the ischium ; (6) the spine of the pubes ; (7) the ilio-pubal ridge ; (8) the ilio-pectineal line ; (9) the anterior and posterior surfaces of the pubes ; (10) the ischio-pubic ramus ; (11) the thyroid or obturator foramen; (12) the symphysis pubis ; (13) the anterior superior and anterior inferior iliac spines; Quadratus lumborum I Erector spinse TUBEROSITY AURICULAR SURFACE POST. INF. SPINE OF ILIUM Transversalis and the iliac fascia GROOVE FOR PUDIC VESSELS AND NERVE Qt. sacro-sciatic ligament x^ JUNCTION OF PUBES Crus penis and Compressor Subpubie AND ISCHIUM Erector penis urethras ligament FIG. 196. THE LEFT HIP-BONE. (Internal surface.) ANT. SUP. SPINE OF ILIUM ANT. INF. SPINE OF ILIUM Fsoas minor ILIO-PUBAL RIDGE GROOVE FOR OBTURATOR NERVE AND VESSELS .SYMPHYSIAL SURFACE Levator ani (14) the posterior superior and posterior inferior iliac spines ; (15) the greater and lesser sacro-sciatic foramina; (16) the greater and lesser sacro-sciatic liga- ments ; (17) the obturator groove. Locate the above points on the cadaver, and in the progress of your dissection find and dissect the soft structures attached to them or in any way bearing important relations thereto. Study thoroughly the os innominatum. Dissection. Quadratus Lumborum. Find the origin on the ilio-lumbar 288 PRACTICAL ANATOMY. ligament and the iliac crest for two inches. Trace the muscle to its insertion into the lower border of the twelfth rib and into the transverse processes of the four upper lumbar vertebrae. Now place the kidney in its original position on this muscle. This muscle lies in front of the erector spinse muscle. In fact, these two muscles form a guide to operations on the kidney. See whether you can demonstrate on your work these structures, in the following relation from behind forward : (i) The quadratns linnbontin ; (2) the lumbar fascia; (3) the last thoracic nerve, the ilio-liypogastric and ilio-ingnhial nerves ; (4) the fatty capsule of the kidney ; (5) the kidney. In operations on the kidney from behind, Quadratus lumborum Faoaa parvus Fsoaa magnus Iliac us Intertransversalis anterior Quadratus lumborum IK;. 197. PSOAS, II.IACUS, AND QUADRATUS LI;.MI;<>KI M. you would find the above relations. Study the above relations until you ha> perfect picture of all these Structures ill your mind. The lower end of the kidney is about one and one-half inches above the iliac crest. The psoas magnus muscle in its relation to vessels and nerves has been previously described. The muse -le has a strong synergist in the iliacus. The-e two are sometimes spoken of as one muscle, with two heads or parts the i/io- />so< c Y\. (Anterior view. \ SACi;rs: Pyriformis COCCYX Levator ani (divided below the ' white line ') Space for obturator internus RECTUM PROSTATE 8YMPHYSIS agt, for gh vessels and mrrc Pyriformis 1'iixfiti/i' fur xcitilic mil! /mdif vessel* nni! nerve ISCHIAL SPINE Coecygeus Cellular interval Levator ani Capsule of prostate, and pubo-prostatio ligaments 1 ic. zoo. MUSCLES OF THE FLOOR OK TIIK PELVIS. the upper border of the greater trocliantcr. It is an external rotator of th< thigh. Its iicn-c-sitfiply is from the sacral plexus. The COCCygeus extends from the spine of the ischium to the anterior snrfaa THE PELVIS. 291 and side of the coccyx. It separates two intermuscular cellular spaces (i) one between itself and the pyriformis, and (2) one between itself and the levator ani. (Figs. 199 and 200.) Its nerve- supply comes from the coccygeal plexus. The levator ani (Fig. 200) arises from the back of the pubic bone and from the inner surface of the ischial spine. Between these two points it arises from the white line. The muscle has a triple insertion : (i) Into the tip of the coccyx ; (2) into the central point of the perineum ; (3) into the rectum. In the female the anterior fibres are inserted into the side of the vagina. Function : It draws the coccyx forward, elevates the floor of the pelvis, and aids in compressing the pelvic viscera. The pelvic white line is formed by a delamination of the obturator fascia. It extends from the spine of the ischium to the pubic bone. (Fig. 200.) It gives partial origin to the levator ani muscle. FEMALE GENERATIVE ORGANS. Now thoroughly cleanse the pelvis and study the internal organs of genera- tion of the female as follows : 1 . Observe in front of the uterus, the bladder, partially covered by perito- neum. In front of the bladder you will see a cellular space called Retzius' space. 2. Pull the uterus to one side and study the relation of the following struc- AMPUUA OF FALLOPIAN TUBE FALLOPIAN TUBE EXTERNAL ANGLE OF UTERUS FIMBRIATED EXTREMITY OF TUBE Hound ligament FIMBRIA OVARIOA Ligament of ovary Anterior peritoneal lamina FIG. 201. THE BROAD LIGAMENT AND ITS CONTENTS, SEKN KROM THE FRONT. (After Sappey). tures : (i) The round ligament of the uterus; (2) the ligament of tJic ovary; (3) the Fallopian tube, or oviduct. As you pull the uterus to the opposite side, you will notice these three structures dispersing to different parts from the angle of the uterus. Trace them out, remembering they are all between the two layers of the broad liga- ment (Fig. 201), as follows : (i) The round ligament to the internal abdominal ring, on the outer side of the deep epigastric artery, down through the inguinal 292 PR A CTICAL ANA TOM ) . canal, out through the external abdominal ring, to the labia majora ; (2) the ovarian ligament terminates in the capsule of the inner end of the ovary ; (3) trace the oviduct /'. e., the Fallopian tube to the outer end of the capsule of the ovary, to which it is attached by one of the fimbriae, called the ovarian fimbria. 3. Locate tJie ureter as it passes down over the brim of the pelvis ; trace it FIG. 202. REPRESENTING SCHEMATICALLY THE RELATION OF THE URETER TO THK BROAD LIGAMENT OF THE UTERUS. A. Peritoneum. B. Peritoneum in relation to bladder. C. Peritoneum pushed ahead of the uterus called broad ligament. D. Space between the two layers of broad ligament containing uterus and adnexa. E. The ureter. F. Uterine and ovarian vessels. carefully as it approaches the posterior surface of the broad ligament. (Fig. 202.) Now, as it passes under, cut a hole in the posterior surface of the broad ligament and follow it across the base and to the bladder. Notice, too, that as you take hold of the broad ligament and lift it up, the ureter remains in place. There would, seem to be little danger of including this structure in the ligature in opera- UTERINE WALL CAVITY OF BODY CAVITY OF CERVIX WITH ARBOR VITA - IMC. 203. FKONTU, SKCTION <>i riu YIUCIN UTKRUS. (After Sappey.) tions on the ovary and tube. As the ureter lies on the levntor ani, there would be more danger of wounding it in operations on the ischio-rectal fossa than in the operation before mentioned. The ureter remains firmly embedded in the deep layer of subperitoncal connective tissue, anil can not be raised by any ordinary amount of traction exerted on the ovary, tube, and broad ligament. THE PELVIS. 2 93 Cervical branch Coronal artery Branch. Brandies Branch I'terine toroti/nl to to EXTREMITY OF branch ligament isthmus ampulla FALLOPIAN TUBE \ Ovarian branches Uterine artery Internal iliac artery Vaginal arteries Azygos artery of vagina FIG. 204. SCHEME OF THE OVARIAN AND UTERINE AND VAGINAL ARTERIES. POSTERIOR SURFACE OF BODY OF UTERUS IT tero -ovarian ligament OVARY FALLOPIAN TUBE Broad ligament FIMBRIATEO EXTREMITY OF TUBE FIMBRIA OVARICA Lower part of broad ligament OS UTERI OS EXTERNUM VAGINAL WALL, DIVIDED AND REFLECTED VAGINA, ANTERIOR WALL FIG. 205. THE FEMALE ORGANS OF GENERATION. (Modified froru Sappey. (Vagina divided and laid open behind.) 294 PRACTICAL ANATOMY. The Ovarian Artery and the Sympathetic Nerve. This artery you will see shining through the peritoneum, passing behind the ureter, opposite the bifurcation of the aorta. You will remember its origin from the aorta, below the renal, and its homologue, the spermatic. Trace it down in this manner : Lift the peritoneum up, over the artery, and cut the same with the scissors. Make every effort not to disturb the artery in its bed. Trace the artery now to the lateral space, between the two folds of broad ligament (Fig. 202), to its distribu- tion and anastomosis, as shown in figure 204. You will find the uterine artery embedded in the side of the uterus, between the two folds of the broad ligament. Find the artery, and trace it out to its origin from the internal iliac artery. (Fig. 204.) You will find an abundant supply of sympathetic nerves forming the uterine plexus. Figure 203 gives a frontal section of the uterus, which you may now imitate. In the angle of the uterus find the opening for the Fallopian tube. Locate the os internum and externum. Figure 206 is a sagittal section. Cut through the vagina and study the utero-vaginal junction. Remember the analysis of the pelvic plexus. Formed : (i) by prolongation of the hypogastric plexus ; (2) by branches from the second, third, and fourth FUNDUS 08 INTERNUM -V- CAVITY OF CERVIX POSTERIOR FORNIX POSTERIOR LIP CAVITY OF BODY REFLEXION OF PERITONEUM ANTERIOR LIP ANTERIOR FORNIX OS EXTERNUM FIG. 206. SAGITTAL SECTION OF THE VIRGIN Unau's. (After Sappey.) sacral nerves ; (3) by branches from the two upper sacral ganglia. Located : By the side of the rectum, vagina, and uterus in the female. Distribution : To all the viscera in the pelvis. The nerves accompany the branches of the internal iliac artery. The nerves proceed from a plexus on the artery ; the plexus proceeds from a ganglion ; the ganglion is supported by the pelvic plexus ; the pelvic plexus is in communication with the hypogastric plexus through a prolongation of this latter. I . \aine (lie ligaments of tlie uterus you hare tints far found, ami explain tlteir derivation. (i) The round ligament; (2) one in front, called the anterior or vesico- uterine; (3) one posterior, the recto-uterine; (4) two sacro-uterine ; (5) two broad ligaments. The round ligament that in your dissection you tr.uvd through the inguinal canal, is lost in tin- lahia majora ; it is homologous to tlu- spermatic cord. It is composed of fibrous and muscular tissue from the uterus. Thecord N attended 1>\ a hood of peritoneum called the canal of Nuck. To SC THE PELVIS. 295 this canal before it becomes obliterated, you must examine female foetuses. The other uterine ligaments are of peritoneal origin, and can and must be demon- strated on your work. 2. From u>/iat source does the n terns receive its blood / Through the uterine branch of the internal iliac artery. It anastomoses above with the ovarian and below with the vaginal arteries. It is surrounded by the uterine plexus of nerves, from the pelvic plexus. (Fig. 204.) 3. Explai)i the rationale of contraction of adhesions in retroflcxions. In the dissection of the peritoneum it was shown that an organ previously invested by peritoneum, may lose its peritoneum, in parte or in toto, by loss of the blood-supply at a given point, by pressure. .(Fig. 170.) The uterus bears the same relation to its investing peritoneum that the colon does to its own. Things equal to the same thing are equal to each other ; the two results are identically the same. The colon, by loss of its specific epithelial element, becomes physio- logically adherent to the parietes, because this adhesion will cause no ulterior hindrance to the function of the colon. The uterus, however, contracts patho- logical adhesions, because the uterus can not, in the position these adhesions entail, discharge its function physiologically. 4. Does the uterus undergo important structural changes / Anatomical structure is always the correlative of function. Not only the uterus, but all its appendages, obey this law of philosophy correlation ot structure and function. In the pre-puberty state, the female genitalia are pro- ducts of growth, not of development ; in the post-puberty state they are the pro- ducts of both growth and development. During menstruation and pregnancy, the uterus and its appendages become relatively changed in size according to function. At the menopause, with cessation of functional activity, these parts become metamorphosed, in a retrograde manner. 5. Explain the anatomical factors in the production of ovarian, uterine, rectal, and uretliro-vcsical reflexes in short, of pelvic reflexes in general and particular. This belongs to physiology, to which chair I refer a detailed answer ; but in order to make you familiar with the anatomical elements involved in reflex phenomena, I know you will pardon just enough physiological digression to keep up an interest in the anatomical regions involved. Reflexes are of two general kinds : (i) simple ; (2) complex. The simplicity of the one depends on the positive conductivity of somatic nerves and the sim- plicity of the factors involved. The complexity "of the other depends on the negative conductivity of sympa- thetic nerves and the complexity of the factors involved. The factors involved are: (i) A nerve-center capable of receiving sensory impressions from sentient areas, and capable of originating motor impulses ; (2) connecting media between the center and the sentient area capable of trans- mitting impressions of both sensation and motion. Somatic nerves are those that supply the body-wall ; they are usually called spinal and cranial. Those nerves are called sympathetic that are set aside principally for the regulation and movement of the viscera. They are the visceral branches of the spinal nerves. The former transmit pain and motion violently, rapidly, positively ; the latter slowly, slight in degree, negatively, compared to the same in somatic areas. (See page 264, et scq.} Law of Projectiles. In addition to the central and peripheral factors, and their motor and sensory communicating media, we must be mindful of the law of 296 PRACTICAL A A' ATOMY. projectiles. The nerves to and from the brain are media by which the impres- sions travel. These impressions, then, and the nerves by which they travel, are projectiles, and are amenable to the law of philosophy governing all projectiles : (i) A projectile follows the line of least resistance ; (2) a projectile follows the point of greatest traction ; (3) a projectile may follow the resultant of these two /. e., the line of greatest traction and the point of least resistance. Anatomical factors determining the above are simply the amount and kind of nerve distribution at the locality whence the reflex proceeds. On this hypo- thesis alone do we account for the reference of both pain and motion, in their logical places, in simplex reflexes. In figure 1 87, a simple reflex, the logical place for the pain is the conjunctiva; the logical place for the motion is in the orbicularis palpebrarum. Here the influences, sensory and motor, follow the greatest direct nerve distribution over cranial nerves having maximal ability to transmit both sensation and motion. On this hypothesis do we account for pain, the result of an irritant, for example, in the ovary, rectum, or uterus, not in its logical place in the organ itself, but in its illogical place, far away in some other part of the body, where both reflex pain and reflex motion may be the symptoms. These are complex reflexes ; still, just as logical in every way and just as amenable to the law of projectiles as simple reflexes. (Fig. 185.) Pain is diagnostically one of the most important subjective symptoms. It is reported peripherally. You must, then, have a thorough knowledge of the cutaneous and membranous distribution of somatic nerves, since it is through these nerves that pain from every organ in the body may make its demurrer. The steps, then, anatomically, in tracing pain for diagnostic purposes are : 1 . What cutaneous or sensory nerves supply the part ? 2. Of what mixed nerve or plexus are they a part ? 3. Where do these mixed nerves leave the spinal canal ? 4. Do they correspond to the six upper intercostals ? 5. Do they correspond to the six lower intercostals ? 6. Do they correspond to the cervical plexus ? 7. Do they correspond to the brachial plexus ? 8. Do they correspond to the lumbar plexus? 9. Do they correspond to the sacral plexus ? 10. What territory of organs does the hypogastric plexus supply? 1 1. What territory does the solar plexus supply? 12. What territory does the cardiac plexus supply? Any considerable pain, then, as previously stated, is reported by a somatic nerve. If this somatic nerve is the innervation pure and simple of the painlul part under consideration, then the pain is a simple direct pain. If, however, as frequently happens, the somatic nerve is the medium through which vast territories are made to suffer, while the exciting cause is in, some remote organ, then this pain is a reflex pain. The somatic nerves may also produce reflex muscular movements in the muscles corresponding to the region of the pain. (See page 264.) The student can not become too well grounded in the philosophical distribu- tion of a mixed nerve : The nerve-trunk that supplies a group of muscles sup- plies also the skin covering those muscles ; the articulation that these muscles move ; the serous or synovial membrane in contact with which these muscles may lie. The six upper intercostal nerves supply, then, not only intercostal muscles, but the pleura as well ; the six lower supply not only the muscles of the abdominal walls, but the peritoneum also. An organ, then, having a syi pathetic nerve-supply, may manifest its pain either in skin, membranes, or artia lations, and still not transcend the logic of the law of reflex phi-nomc-mi. >matic THIGH AND LEG. DISSECTION OF THE ANTERIOR REGIONS OF THE THIGH AND LEG AND OF THE ADDUCTOR REGION OF THE THIGH. The following review of the practical osteological points on the bones of the lower extremity must be thoroughly mastered before the student can do intelligent work on the cadaver. These points the student must study with the bones in hand. Simply committing to memory a few pages of technical names, with no knowledge of a practical application of the subject, would be as useless here as in other departments of science. The Tibia : Name the bony points on tlie tibia of practical importance in dissection. The internal tuberosity has one articular surface. The external tuberosity has two articular surfaces. The tubercle, into which the ligamentum patellae is inserted. The crest, or anterior border, is subcutaneous. The internal surface is three-fourths subcutaneous. The upper two-thirds of the external surface is occupied by tibialis anticus. The popliteal notch transmits the popliteal artery and vein. The oblique line is on the posterior surface. The femoral articular surfaces of the head. The internal malleolus of the tibia. The astragaloid articular surfaces of the tibia. The posterior surface and its subdivisions. The nutrient canal, directed from the knee. How many articular surfaces has the tibia ? It has six articular surfaces two femoral, two fibular, and two astragaloid. The student must find these surfaces and name technically the articulations they assist in forming. (See rule for forming compound words in introductory chapter.) What can yon say of the internal surface of the tibia / It is subcutaneous in its lower three-fourths. (Fig. 207.) Its upper one-fourth is occupied by the insertions of the semitendinosus and gracilis muscles, which are inserted by tendons, and the sartorius, inserted by aponeurosis. What important flexor muscle is inserted into the posterior part of tJic internal tnherosity ? The tendon of the semimembranosus muscle. It will be seen presently that this muscle has also three aponeurotic insertions that have very important relations and functions in the vicinity of the knee-joint. Describe the posterior surface of the tibia. It is divided by two lines an oblique and a vertical one into three sub- divisions. (Fig. 208.) One of the three surfaces is occupied by the popliteus muscle ; a second by the flexor longus digitorum ; a third by the tibialis posticus. 20 297 298 PRACTICAL ANATOMY. Describe fully the oblique line of the tibia. (Fig. 208.) It extends from the fibular articular surface to the middle one-third of the bone, on the inner border. It may be considered as possessing three lips an upper, a middle, and a lower. Into the upper is inserted the popliteal fascia ; from the middle arises the tibial head of the soleus ; from the lower, the flexor longus digitorum and tibialis posticus. Describe the vertical line. It extends in a curved line downward and outward to the middle one-third of the outer or interosseous border of the tibia. It separates the surfaces occupied by the tibialis posticus and flexor longus digitorum muscles. It also marks the location of the nutrient foramen of the tibia, proceeding, according to rule, from the knee. Name the important parts of the internal mall coins of the tibia. Posteriorly are two grooves for the tibialis posticus and flexor longus digi- torum ; one surface articulates with the astragalus ; to the apex is attached the internal lateral ligament of the ankle-joint. The Fibula: Name the points on the fibula of importance in practical anatomy. The head, for insertion of the biceps tendon. The styloid process of the head, for external lateral ligament. The tibial articular surface. The external malleolus of the fibula. The anterior surface of the fibula. The outer surface of the fibula. The internal surface of the fibula. The posterior surface of the fibula. What is the importance of the anterior surface of the fibula / (Fig. 207.) Its width is one-fourth of an inch. It gives origin to the extensor proprius or extensor longus hallucis, the extensor longus digitorum, the peroneus tertius i. e., all the muscles on the front of the leg, except the tibialis anticus. What can you say about the external surface of the fibula f (Fig. 207.) It gives origin to and is occupied by the peroneus longus and peroneus brevis the former occupies the upper two-thirds ; the latter, the lower two-thirds. What is the importance of the posterior surface of 'the fibula / It gives origin in its upper one-third to the fibular head of the soleus ; in its lower two-thirds to the flexor longus hallucis. (Fig. 208.) Give the importance of the internal surface of tJic fibula. It gives attachment to the tibialis posticus i. t\, to the fibular head of this muscle. / / 'hat can you say of the patella ? It is the largest sesamoid bone in the body. It is developed in the common tendon of insertion for the group of muscles that extend the leg on the thigh the quadriceps extensor fcinoris. It has two articular surfaces, corresponding to tin- trochlear articular surface of the femur. The ligamentum patellae is inserted into the tubercle of the tibia. A pad of fat and a hursa intervene between the patella and tibia, except at the insertion. The Foot and Ankle : \aine the osteological points of the foot and ankle of importance in dissection. The posterior surface of the calcaneum. The sustentaculum tali of the calcaneum. The peroneal grooves of the calcaneum. The inner and outer tuberositics of the calcaneum. The cuboid surface of the calcaneum. The astragaloid surface of the calcaneum. THIGH AND LEG. 299 The tuberosity of the scaphoid bone. The cuneiform articular surfaces of the scaphoid. The medio-tarsal articulation. The base of the first metatarsal bone. The base of the fifth metatarsal bone. Wliat two tendons do yon expect to find on the outer surface of the calcanemn / The tendons of the peroneus longus and brevis. They are separated by a little spine of bone the peroneal intertendinous spine. Each tendon is in a separate canal here, but higher up, behind the outer malleolus, they are in the same canal. How woidd you describe the peronens innscle so as to give the bony parts of t/ie limb due prominence ? The peroneus longus arises from the outer surface of the fibula in its upper two-thirds ; its tendon passes behind the external malleolus of the fibula, with the tendon of the peroneus brevis ; it passes on the outer surface of the calcaneum, in the inferior peroneal groove ; it passes through a groove on the under surface of the cuboid bone ; it is tendinously inserted into the base of the first meta- tarsal bone, having traversed an osseo-aponeurotic canal, from the cuboid bone to its insertion. Describe the peroneus brevis. It arises from the outer surface of the fibula, middle one-third ; passes behind the external malleolus of the fibula ; passes through the superior peroneal groove, on the outer surface of the calcaneum ; and is inserted into the base of the fifth metatarsal bone. Name the grooves through which the tendon of the flexor longus Jiallucis passes. This muscle arises from the posterior surface of the fibula, in its middle two- thirds. It passes through a groove in the posterior part of the tibia (Fig. 208) ; through a second groove, in the posterior surface of the astragalus, one inch below the first groove ; through a third groove, on the under surface of the sus- tent'aculum tali of the os calcis or calcaneum ; through a fourth groove, between the two sesamoid bones, in the tendons of the flexor brevis hallucis, at the meta- tarso-phalangeal articulation of the great toe. Name the muscles attached to t/ie inferior surface of the os calcis. The abductor hallucis, abductor minimi digiti, flexor brevis digitorum, and musculus accessorius. Describe tlie insertion of the antagonistic muscles tibia Us anticus and tibialis posticus. The tibialis anticus is inserted into the inner surface of the internal cuneiform bone and adjacent part of the base of the first metatarsal bone. (Figs. 2 1 3-2 15.) The tibialis posticus is inserted into the tuberosity of the scaphoid bone, into the sustentaculum tali, into the bases of the second, third, and fourth metatarsal bones, and into all the tarsal bones except the astragalus. How shall 'we recognize and knoiv these numerous small insertions of the tibialis posticus muscle ? You can easily trace them as small, tendinous bands from the tuberosity of the scaphoid bone to all other insertional points. (Fig. 215.) Describe the importance of the sustentaculum tali. A superior surface articulates with the inner articular facet of the astragalus ; its inferior surface is grooved and lined by synovial membrane, for the transmis- sion of the tendon of the flexor longus hallucis. Give tlie importance of the superior surface of the calcaneum. (i) It gives origin to the extensor brevis digitorum ; (2) it articulates with the astragalus by two surfaces. What is the importance of the posterior surface of the os calcis ? Into this surface is inserted the tendo Achillis. 300 PRACTICAL ANATOMY. SPINE.OF TIBIA Internal flbro-cartilage Coronary ligament Anterior crucial ligament INNER TUBEROSITY Internal lateral ligament Ligamentum patellae (Quadriceps extensor) Oracilis Sartorius Semitendinosua EXTERNAL SURFACE OF TIBIA Tibialis anticus ANTERIOR BORDER OR CREST OF THE TIBIA INTERNAL SURFACE OF TIBIA Interosneous membrane Anterior ligament of ankle-joint. Internal lateral ligament INTERNAL MALLEOLUS External flbro-oartilage Capsule OUTER TUBEROSITY Biceps and the Anterior tibio-flbular ligament External lateral ligament Extensor longus digitorum Peroneus longus Peroueus brevli Extensor longus digitorum PERONEAL SURFACE OF FIBULA EXTENSOR SURFACE OF FIBULA Extensor proprius hallucis Anterior tibio-flbular ligament EXTERNAL MALLEOLUS External lateral ligament (Anterior fasciculus) FIG. 207. Tin 1 iii TII;IA AM> FiiiUi.A. (Anterior view.) THIGH AND LEG. POPLITEAL NOTCH External flbro-cartilage Capsule Posterior crucial ligament STYLOID PROCESS Posterior tibio-flbular ligament Tibialis posticus Flexor lougus hallucii FLEXOR SURFACE OF FIBULA NUTRIENT FORAMEN FIBULA Feroneus brevis Posterior tibio-flbular ligament GROOVE FOR FLEXOR LONGUS HALLUCIS External lateral ligament (posterior fasciculus) External lateral ligament (middle 1'asciculusj Internal flbro-cartilage Capsule Semimembranosus Popliteus OBLIQUE LINE Soleua POSTERIOR SURFACE OF TIBIA Flexor longuu digitorum TIBIA GROOVE FOR T1B1ALIS POSTICUS AND FLEXOR LONGUS DIGITORUM Internal lateral ligament Posterior ligament of ankle-joint FIG. 208. THE LEFT TIBIA AND FIBULA. (Posterior view.) 302 PRACTICAL ANATOMY. Locate by limitation tlie medio-tarsal joint, and give the surgical importance thereof. Posteriorly, it is limited by the calcaneum and astragalus ; anteriorly, by the cuboid and scaphoid. It is through this articulation the knife passes in Chopart's amputation at the medio-tarsal articulation. Locate by limitation the tarso-metatarsal articulation, and give its surgical importance. It is limited posteriorly by the cuboid and cuneiform bones ; anteriorly, by the bases of the metatarsal bones. It is through this articulation Lisfranc's amputation is made. Locate on the cadaver : (i) The crest of the ilium ; (2) the anterior iliac spine ; (3) the spine of the pubes ; (4) the symphysis pubis ; (5) the pubic crest; (6) the femoral condyles, internal and external ; (7) the tuberosities of the tibia, internal and external ; (8) the head, neck, and styloids of the fibula ; (9) the crest of the tibia ; (10) the subcutaneous inner surface of the tibia ; (i i) the inner and outer malleoli ; (12) the os calcis ; (13) the cuboid bone ; (14) the tuberosity of the scaphoid; (15) the patella and ligamentum patellae; (16) the tubercle of the tibia ; (17) Poupart's ligament or crural arch. How to Make Skin Incisions. First cut through the skin from the centre of Poupart's ligament to the centre of the second toe, the incision pass- ing through the mid-line of the patella. The second cut extends along Poupart's ligament, from the anterior superior spine of the ilium to the symphysis pubis. The third cut extends from one femoral condyle to the other. The fourth cut extends from the inner to the outer malleolus. Now remove the skin. Always follow this rule in removing the skin : Cut closely enough to the skin to permit light to shine through. THE SUPERFICIAL FASCIA. The superficial fascia is the second covering of the body. It contains a vari- able amount of fat. When, as a result of starvation or malnutrition, this fat disappears, the skin lies closely upon the deep fascia, and bony eminences are numerous in other words, the individual is emaciated. This fascia always consists of two layers an upper layer, containing the fat ; a deep layer, in which are found the cutaneous vessels and nerves. The immense fatty mass in the superficial fascia is recorded in the surgical description of operations as the panniculus adiposus. Remember that there are numerous arteries in the super- ficial fascia for the nutrition of the skin, but few of them have special names. Collectively they are known as superficial, dermal, or cutaneous arteries. There are also numerous veins in this fascia. On account of their large size ami surgical importance, quite a number have received special names as long and short saphenous ; still here, too, the rank and file of veins are collectively desig- nated, as are the arteries viz. : superficial, dermal, or cutaneous. By common consent, the word superficial is used by anatomists to designate anything in tlu superficial fascia ; hence all arteries, veins, nerves, muscles, and lymphatics, ii this fascia may properly be collectively designated superficial. I laving removed the skin, according to directions previously given, consult figures 209, 210, and 21 1, and find in the deep layer of the superficial fascia the following cutaneous or superficial structures : 1. The dorsal venous arch of the foot arcus dorsalis peclis. 2. The long saphenous vein and its tributaries, 3. The short saphenous vein and its tributaries. 4. The internal and external femoral cutaneous veins. 5. The superficial epigastric vein and its tributaries. >n E THIGH AND LEG. 33 6. The superficial circumflex iliac vein and tributaries. 7. The superficial external pudic vein. 8. The spermatic cord, just below the pubic spine. (Fig. 211.) 9. Superficial inguinal and femoral lymphatic glands. (Fig. 210.) 10. The long saphenous nerve, with a vein of like name. (Figs. 209 and 210.) 1 1. The short saphenous nerve and vein (posteriorly). 12. The cutaneous branch of the musculo-cutaneous nerve. (Fig. 209.) 13. The internal, middle, and external cutaneous nerves. (Fig. 209.) 14. The ilio-hypogastric and genito-crural nerves. (Fig. 209.) 15. The patellar plexus, formed by the union of cutaneous branches, from EXTERNAL CUTA- NEOUS ILIO- INGUINAL TWIG FROM IN- TERNAL CUTA- NEOUS INTERNAL CUTA- NEOUS PATELLAR BRANCH OF LONG SAPHE- NOUS LONG SAPHE- NOUS ANTERIOR TIBIAL GENITO- CRURAL MIDDLE CUTA- NEOUS CUTA- NEOUS BRANCH OF EXTERNAL POPLITEAL MUSCULO- CUTA- NEOUS SHORT SAPHE- NOUS FIG. 209. DISTRIBUTION OF CUTANEOUS NERVES ON THE ANTERIOR ASPECT OF THE INFERIOR EXTREMITY. the internal, middle, external cutaneous nerves, and a branch from the long saphenous and obturator to supply the skin over the insertion of the extensor muscles of the leg, according to Hilton's /aw. (Fig. 211.) 1 6. The subsartorial plexus, formed by branches from the obturator, long saphenous, and internal cutaneous nerves, to supply the skin over the insertion of the adductors, according to Hilton's lazv. 17. The prepatellar bursa, found in the superficial fascia in front of the patella. Dorsal Arch (Fig. 210.) How Formed. This arch is seen on the dorsum of the foot about one inch behind the clefts of the toes. It is formed by the conflu- ence of the veins from the skin of the toes. It lies upon the cutaneous nerves PRACTICAL ANATOMY. Superficial lymphatics from lateral VOU vf I'\rscin. Deep fascia is continuous with periosteum at subcut.HH-oiis areas. These are called the attachments. Tin- deep fascial attach- ments of the lower limb are as follows. In the region of the hip : (i) To crest ot ilium ; (2) to pubic spine and body ; (3) to ischii. -pubic ramus ; (4) to the tubcr- usity of ischium ; (5) to sacrum and coccyx. In the knee region, demonstrate THIGH AND LEG. 39 its attachment to : (i) The patella ; (2) the tuberosities ; (3) the condyles ; (4) the crest and inner surface of the tibia. In the ankle region, see its attachment : (i) To the os calcis ; (2) to the malleoli ; (3) to the tuberosity of the scaphoid bone and numerous other places. Saphenous Opening. This is the largest opening in the deep fascia. It is situated between the iliac and pubic portions of the fascia lata. Behind it, or on its floor, is the femoral sheath, containing the femoral artery, vein, and canal. In front of the opening, forming its roof or covering, is the superficial fascia, called in this locality, the cribriform fascia. The structures passing through the saphenous opening are numerous : the long saphenous vein and the small vessels given off from the common femoral artery and vein, and some lymphatic vessels. Cribriform Fascia. Just that part of the deep layer of the superficial fascia, that covers the saphenous opening, is called by this name. It was so called on account of the numerous perforations, transmitting the structures referred to in the previous paragraph. The word " cribriform " means sieve-like. Importance. Since fascia often determines the direction taken by burrowing pus, or the course of a bullet, its various superficial attachments should be care- FIG. 212. THE FEMORAL RING AND SAPHENOUS OPKNING. (After Holden.) (The arrow is introduced into the femoral ring.) i. Crural arch. 2. Saphenous opening of the fascia lata. 3. Saphena vein. 4. Femoral vein. 5. Gimbernat's ligament. 6. External abdominal ring. 7. Position of internal ring. fully examined, and its deep ones found by dissection. The guide to finding these is to remember that muscles are arranged in antagonistic groups, and that these groups are called musculatures, and that these musculatures are separated by septa, and these septa are attached to bone i. e., continuous with its periosteum. The Application. Now apply the principle of musculatures to the lower ex- tremity. On the thigh you will presently find: (i) An extensor group of mus- cles in front ; (2) a flexor group behind ; (3) an adductor group internally. You will also find: (i) A septum between the extensor group and flexor group ; (2) between the flexor group and the adductor group ; (3) between the adductor group and the extensor group. Again, below the knee you will find : (i) A group of muscles on the anterior tibio-fibular region ; (2) a group on the outer surface of the fibula ; (3) two groups on the posterior tibio-fibular region. Here, also, you may demonstrate the rule that adjacent musculatures are separated from one another by fascial septa, since here are strong bands of fascia separating the peronei muscles on the outer sur- face of the fibula, from different musculatures both in front and behind. Like- wise, on the back of the leg, the superficial group is separated from the deep by the transverse fascia, and both these groups from lateral musculatures. 310 PRACTICAL ANATOMY. ANTERIOR REGION OF LEG. Remove carefully the deep fascia. (Fig. 210.) You have now, by the re- moval of the skin and superficial fascia, exposed the deep fascia covering all the muscles on the anterior and outer regions of the leg (Fig. 213): 1. The cutaneous branch of the musculo-cutaneous nerve. 2. The tibialis anticus and the tuberosity of scaphoid bone. 3. The extensor proprius hallucis muscle. 4. The extensor longus digitorum muscle. 5. The peroneus tertius muscle. 6. The extensor brevis digitorum muscle. Now dissect down between the tibialis anticus and the extensor proprius hallucis by cutting through the deep fascia with scissors and find the anterior tibial nerve and vessels. (Fig. 214.) Anterior Tibial Artery. It is one of the two terminal branches of the pop- liteal artery. It gains the front of the leg by passing between the two heads of the tibialis posticus and interosseous membrane. It lies in a deep groove, bounded internally by the tibialis anticus ; externally, by the extensor longus digitorum and extensor proprius hallucis. It terminates on the dorsum of the foot, continu- ing its course under the name of dorsalis pedis. Its branches are : (i) The ante- rior tibial recurrent, which anastomoses with the articular branches of the popliteal and anastomotica magna ; (2) posterior tibial recurrent, when present, is given off before the anterior tibial passes through the interosseous membrane ; (3) mus- cular branches, which supply the muscles on the anterior region of the leg (Fig. 214) ; (4) malleolar branches, which supply the ankle-joint. On the back of the foot you cut through the deep fascia between the extensor proprius hallucis and extensor, longus digitorum muscles, to find the dorsalis pedis artery. Dorsalis Pedis Artery. This is a continuation of the anterior tibial. It lies between the extensor proprius hallucis and extensor longus digitorum, on the dorsum of the foot. (Fig. 214.) It gives off: (i) A communicating branch to the external plantar, by which the plantar arch is completed ; (2) a tarsal artery to the extensor brevis digitorum and the tarsus ; (3) the dorsalis hallucis to the great toe ; (4) interosseous arteries to the interosseous spaces and their contents. Trace the arteries out carefully with the forceps. Remember they are beneath the dorsal fascia. Anterior Tibial Nerve. It is a branch of the external popliteal nerve, being given off with the musculo-cutaneous nerve. It gives off articular branches, ac- cording to Hilton's law, to the (i) ankle-joint, (2) the tarsal, and (3) the metatarsi phalangeal joints. It gives muscular branches to the extensor brevis digitorui and to all the muscles on the anterior regions of the tibia and fibula. Muscles on Anterior Surface of Fibula. These are : (i) Extensor proprius hallucis ; (2) extensor Jongus digitorum ; (3) peroneous tertius, the fifth tender of the extensor longus digitorum. Insertion of Extensor Brevis Digitorum. This muscle has four tendon- The first is inserted independently into the base of the first phalanx of the great toe ; the remaining three are inserted, conjointly with the tendons of the extensor longus digitorum, into the bases of the second and third phalanges. Give nen>e-supply of the Jive tmtsc/cs nw exposed on the anterior tibio-filntlar region. The anterior tibial, a branch of the external popliteal Intermuscular Septum. Examine the septum that separates the muscles the anterior surface of the fibula from the peronei on the external surface. How to Dissect these Muscles. Tibialis Anticus. Cut through tl I us ;: THIGH AND LEG. 311 anterior annular ligament on the tendon of the muscle. Now follow the tendon to its insertion into the internal cuneiform bone and base of the Ligamentum patellae CiastrocnemiuB Extensor propriua halluei Dorsal interoasei Peroueus longus Tibiaha anticus Peroneus tertius Extensor loagua digitorum Peroneus tertius Extensor brevis digitorum FIG. 213. THE MUSCLES OF THE FRONT OF THE LEG. first metatarsal. Then trace the muscle to its origin : (i) the outer surface of the tibia, upper two-thirds ; (2) outer tuberosity. Notice the nerve-supply and blood- sijpply. 312 PRACTICAL ANATOMY. Extensor Proprins Hallucis. Begin at the end of the great toe and cut down on the tendon. Follow it up through a separate compartment under the Superior internal articular artery Inferior internal articular artery Anterior tibial recurrent artery Anterior tibial artery Tibialis anticus muscle ANTERIOR TIBIAL NERVE Extensor longuB halluois Internal malleolar artery Anterior annular ligament Dnrsalis pedis artery Innermost tendon of extensor brevis digitorum Comitiuiiicntinij branch Dorsalis hallucis artery Superior external articular artery Inferior external articular artery Extensor longus digitorum Extensor longus digitorum. turned back Peroneus tertiua Anterior peroneal artery External malleolar artery Peroneus brevis muscle 1\ ift Extensor brevis digitorui External tarsal branch Metatanal branch Dorsal inlerosseous artery FIG. 214. THK ANTKRIOK TlBIAl ARTERY, DORSAL ARTKRY OF THK FOOT, AM> AMKKH I'KROM-.AI. ARTKRY, AND TIIKIR BRANCH M. annular ligament to its origin on the middle half of the anterior surface of the fibula and interossrous membrane. The licensor Longus nigitornw. To dissect this muscle successfully, c nl THIGH AND LEG. 313 down on the same through the anterior annular ligament. Then use your forceps as a director, and carefully cut the dorsal fascia over each of the four Teudo Achillis Extensor brevis digitorum Extensor longue halluois Extensor brevis digitorum Peroneus brevis Peroneus tertius METATARSUS FIRST PHALANX SECOND PHALANX THIRD PHALANX cteusor longus digitorum FIG. 215. THE LEFT FOOT. (Dorsal surface.) (Study origin and insertion of muscles on this figure and compare with your dissection.) 'tendons. In like manner trace each tendon to the end of the toe. Notice that each tendon divides in three slips, on the dorsal surface of the first phalanx ; that the middle slip is inserted into the base of the second phalanx ; that the 21 3*4 PRACTICAL ANATOMY. SPINE, OF TIBIA Internal nbro-cartilage Coronary ligament Anterior crucial ligament INNER TUBEROSITY Internal lateral ligament Ligamentum patellae (Quadriceps extensor) Gracilis Sartorius SemitendinoauB EXTERNAL SURFACE OF TIBIA Tibialis anticus ANTtRIOR BORDER OR CREST OF THE TIBIA INTERNAL SURFACE OF TIBIA InteroBBeous membrane Interior ligament of ankle-joint Internal lateral ligament INTERNAL MALLEOLUS External nbro-cartilage Capsule OUTER TUBEROSITY Biceps and the Anterior tibio-flbular ligament External lateral ligament Extensor longus digitorum Peroneus lougus Peroneus brevls PERONEAL SURFACE OF FIBULA EXTENSOR SURFACE OF FIBULA Extensor propriua haliucis FIBULA Peroneus tertius SUBCUTANEOUS PORTION Anterior tibio-flbular ligament EXTERNAL MALLEOLUS External lateral ligament (Anterior fasciculus) FIG. 216. THE LEFT THIIA AND FIHUI.A. (Anterior view.) (Study origin of muscles on this figure and compare with your dissection.) THIGH AND LEG. 315 two lateral slips are inserted into the base of the third phalanx. Also notice the relation of the tendons of this muscle to those of the extensor brevis digi- torum. Origin, outer tuberosity of the tibia and anterior surface of fibula. The Peroneus Tertius. Find the insertion of this muscle in the base of the fifth metatarsal. (Fig. 215.) Trace it to the anterior surface of the fibula, and notice that it blends with the preceding muscle, a part of which it really is. (Fig. 207.) THIGH, ANTERIOR AND INTERNAL REGIONS. Remove the deep fascia and expose the vessels, nerves, and muscles. (Figs. 218, 219, and 220.) First locate the sartorius. (Fig. 218.) Begin at the anterior superior iliac spine (Fig. 226) and expose the muscle to its insertion (Fig. 207) into the tibia, by gently removing all deep fascia. Now lift up the muscle from its bed, taking care not to damage the vessels and nerves that enter it. Notice that this muscle is crossed by one and pierced by another branch of the middle cutaneous nerve. (Fig. 211.) Locate the gracilis next, on the inner surface of the thigh. (Figs. 218 and 219.) Trace it from the descending ramus of the pubes (Fig. 226) to its inser- tion into the inner surface of the tibia (Fig. 207), taking care not to damage the nerve branches of the obturator that enter it. This dissecting, by which this muscle is separated from its fellow-muscles, must be done with the forceps. Locate the adductor longus. (Fig. 218.) Trace it from the anterior surface of the pubes to its insertion into the middle of the middle lip of the linea aspera. (Fig. 227.) Divide the connective tissue between this muscle and the pectineus. (Fig. 218.) Now cut the adductor longus, at its origin, and turn the same aside. (Fig. 219.) Also cut the pectineus and turn it aside. (Fig. 218.) Obturator Nerve, Anterior Division (Fig. 219). This you will see lying on the adductor brevis. (Fig. 219.) Take this nerve up gently, and follow out its branches to : (i) The gracilis ; (2) the adductor longus ; (3) the adductor brevis ; (4) the sartorius ; (5) a branch to the hip-joint ; (6) a branch to the femoral artery ; (7) an occasional branch to the pectineus muscle ; (8) a cutaneous branch to assist the long saphenous and internal cutaneous in forming the subsartorial plexus. Obturator Nerve, Posterior Division. This lies on the adductor magnus. The adductor brevis muscle then separates the anterior from the posterior divi- sion of the nerve. This division supplies : (i) The obturator externus ; (2) the adductor magnus; (3) an articular branch to the hip-joint; (4) an articular branch to the knee. Why does the obturator nerve send a branch to the knee ? Because this nerve supplies the sartorius muscle, a muscle that moves the knee-joint. (Fig. 219.) Hoiv does the articular branch from the obturator nerve enter the hip-joint / It passes through the cotyloid notch. When the accessory obturator nerve is present, wliere may it be found / To the inner side of the psoas magnus muscle. What is the function of the subsartorial plexus? To supply the skin over the adductor muscles, and to exercise a sensory balance of power between the obturator and anterior crural nerves. The Anterior Crural Nerve (Fig. 219). You will find the main trunk of this nerve deeply buried in a space between the iliacus and psoas magnus. (Fig. 197.) Take this nerve up on your finger and gently follow out its muscular branches to all the muscles on the front of the thigh : (i) Sartorius ; (2) rectus femoris ; (3) PRACTICAL ANATOMY. vastus internus ; (4) vastus externus ; (5) crureus ; (6) subcrureus ; (7) pectineus. In tracing these nerves, divide the connective tissue in the direction of the long axis EXTERNAL POPLITEAL NER VE RECURRENT ARTICULAR MUSCULO-CUTANEO US BRANCH TO PERONEUS LONG US BRANCH TO EXTENSOR LONG US DIG I TO RUM BRANCH TO PERONEUS B RE VIS MUSCULO-CUTANEO US MUSCUL O-CUTA NEO US (OI'TKIt S1IOR T SA PHENO US COLLA TERA I, BRAN<'lli-:x OF EX- //;/.' .V.I/, XAP/fENOUS .I.Y/J .vr.sYV/.o- CUTAM:nrs TO TOES ANTERIOR TIBIAL SKI: vi-: Anterior tibial artery Tibialia anticua ANTERIOR TIBIAL NERVE M U8CULO-CUTA Si-:< > ' w (INNER DIVISION) ANTERIOR TIBIAL (<>r n-:i: />/V/ //> ItlsTIUHCTION TO DIGITORUM ANTEIUOi: TIlilAL d.\.\i:i; i>i VISION) COLLATERAL .v< ///> or rxrr /.<>-(//. i. \/-:o i .s ) co/,/,.1 TV?/? BRANCHl MU8CULC TO TOES l-'lC. 217. BkAN'CHES OF THE E.Vl'KKN.U. 1'ol'l.lTKAI. NhK\l. of the ncrrc nc-rcr crossivise. And trace it to the skin covering the same by (i) The internal cutaneous ; (2) the middle cutaneous ; (3) the long saphenou.< The Femoral Artery (Fig. 223). Get your finger under this vessel and trac THIGH AND LEG. 317 out its branches. Great care must be taken to divide the connective tissue binding the artery and vein together. To learn the branches of this artery, see page 320. Dissection of the Rectus (Fig. 2 1 8). You can easily lift this muscle from its b^d. It lies on the vastus interims. (Fig. 220.) Joining the rectus on its outer Adductor brevis Adductor longua Adductor magnus Vastus InternuB Tendon of sartorius Gluteus medius Glutens minimus Tensor vaginae femoria Sartorius - Rectus femoris o-tibial band of fascia lata astua ezternus Ligamentum patellae Fir,. 2l8. MUSCLES OF THE FRONT OF THE THIGH. border is the vastus cxternus. (Fig. 2 1 8.) Trace the rectus upward and develop its two heads (Fig. 226) : (i) The straight, from the anterior inferior iliac spine ; (2) the reflected, from the depression above the brim of the acetabulum. Notice the nerves and arteries enter the under surface, and trace them to their sources. (Fig. 223.) 3i8 PRACTICAL ANATOMY. The Vasti Internus and Externus (Fig. 220). Cut the rectus four inches above the patella and turn it aside, guarding well the vessels and nerves. You will take particular notice of the form of the groove or bed in which the rectus lay. This bed is on the front surface of the vastus internus, and is called the crureus^ muscle. (Fig. 220.) It is not a separate muscle, but only that part of the vastus internus on which the rectus lay. Along the outer margin of the rectus-bed you will see the descending branch of the external circumflex artery (Fig. 223), Femoral vein Femoral artery I Pectineus OBTURATOR (ANTERIOR DIV.) OBTURATOR (POSTERIOR DIVISION) Adductor longus Adductor brevis OBTURATOR (ANTERIOR DIVISION) Oracilis Adductor magnus GENICULA TE BRANCH OF OBTURATOR Seml-membranoBUB Anoitomotica artery PA TELLAR BRANCH OF LONG SAPHENOUS Sartorlua Iliacus ANTERIOR CRURAL Psoas Tensor vaginae femoris Prqfunda artery Fectineus Hectus femoris LONG SAPHENOUS NERVE TO VASTUS IN TERN US Adductor lonftus Femoral artery FIG. 219. ANTERIOR CRIKAI AND < IUTURATOR NERVES. (Ellis.) attended by the nerve to the vastus externus. This artery lies in a groove which separates the vastus internus from the vastus externus. Develop this groove, and you will be able to turn the vastus externus aside. This latter muscle, the vastus externus, overlaps the outer part of the vastus interims as far as the margin of the rectus. (Fig. 218.) Now trace the rectus and the two vasti downward to their conjoined insertion into the tubercle of the tibia, by the ligamentum patelhe. (Fig. 216.) Also note that the vastus internus receives its nerve-supply on ib anterior surface. (Fig. 219.) Obturator Nerve (Fig. 219). This is a branch of the lumbar plexus. It passe.- THIGH AND LEG. below the brim of the pelvis, with the obturator artery and vein. (Fig. 223.) It escapes from the pelvis by the obturator canal, on the under surface of the hori- zontal ramus of the pubes. It divides into anterior and posterior branches. These are separated by the adductor brevis muscle. (Fig. 219.) The anterior branch Obturator externus Adductor longus Adductor magnus Adductor longus Vastus internus Reotua femoris Xiigamentum patellae Reotua tendon GHuteus medius Gluteus minimus Adductor brevis Vastus ezternus Biceps Ilio-tibial band FIG. 220. THE DEEP MUSCLES OF THE^ FRONT OF THE THIGH. supplies the graciiis, adductor longus, adductor brevis, and sartorius. (Fig. 221.) The posterior branch supplies the adductor magnus, the knee, and the hip. Branches of the Anterior Crural Nerve. This nerve is from the lumbar plexus. (Fig. 193.) It is in a groove under the crural arch between the iliacus and psoas magnus. It gives off the following branches : 320 PRACTICAL ANATOMY. 1. A branch to the iliacns muscle. This is given off within the pelvis, but is easily found distributed to the under surface of the muscle. 2. Cutaneous brandies the long saphenous, the internal and middle cutaneous. 3. A small branch to the femoral artery. This is given off within the pelvis. 4. Muscular branches to all the muscles on the front of the thigh. Note that the sartorius muscle is supplied either by the middle or internal cutaneous nerve. 5. An articular brancJi to the hip, given off from the branch to the rectus ; also articular branches to the knee, from the nerves to the two vasti. FIG. 221. PECTIN EUS AND ADDUCTOR LONGUS. I. Femur. 2. Ilium. 3. Pubis. 4. Pectineus. 5. Adductor longus. 6. Lower portion of adductor magnus. 7. Tendon of rectus femoris. 8, 8. Orifices for vessels. 9. Orifices for femoral vessels. FIG. 222. ADDUCTOR BRKVIS AND AI>DU MAGNUS. . Femur. 2. Ilium. 3. Pubis. 4. Obturator externus. 5- Upper portion of adductor magnus. 6. Upper portion of adductor brevis. 7. Inferior portion of adductor brevis. 8. Middle portion of adductor magnu. 9. Inferior portion. lo. Tendon of insertion into internal condyle o femur. n. Orifice for femoral vessels. 12. Orifice for internal circumflex artery and veins. Branches of the Femoral Artery. The common femoral is a continuation of the external iliac. (Fig. 223.) Usually, it is about one and one-half inches in length. It then divides into the superficial and deep femoral. F.ach has branches. Branches of the Common Femoral Artery. (i) Superficial circumflex iliac ; (2) superficial epigastric ; (3) superficial external pudic ; (4) deep external pudic. These are all small and surgically insignificant branches. (Fig. 223.) Branches of the Profunda. (i) The internal circumflex ; (2) the external circumflex ; (3) the three perforating arteries. arc perforating arteries so called .' 1 1 THIGH AND LEG. 321 Because they perforate the adductor group, to reach the hamstring muscles on the back of the thigh, which they supply. (Fig. 222.) The external circumflex supplies the muscles on the anterior part of the thigh. (Fig. 223.) Its ascending branch anastomoses with the gluteal and circumflex iliac; its descending branch with the superior external articular branch of the popliteal artery. The Use of the Internal Circumflex (Fig. 223). To assist the obturator artery in supplying the hip-joint and the adductor muscles, and to anastomose with the sciatic and external circumflex to complete the crucial anastomosis. \\ r kcre, on the posterior part of tlic thigh, will you find the terminal branch of the internal circumflex arterv f Between the quadratus femoris and the adductor magnus. Branches of the Superficial Femoral Artery. The superficial femoral artery lies in both Scarpa's triangle and Hunter's canal surgical areas to be pres- ently described. The branches given off by this artery are : muscular, to the sar- torius and vastus interims ; the anastomotica magna, given off just before the artery leaves Hunter's canal. The anastomotica niagna divides into two branches: (i) A superficial one, that accompanies the long saphenous nerve, and (2) a deep one, that anastomoses with the internal articular and the anterior recurrent tibial. This artery supplies branches to the knee-joint. It will be found on the bone, above the condyle, forming an arch with the external articular. Review of tlic Work on the Thigh. Thus far in the deep dissection of the an- terior and lateral regions of the thigh, you have : 1. Traced the origin, insertion, and nerve-supply of the sartorius, and lifted this muscle from its bed. 2. You have found the exact origin and insertion of the gracilis, and liberated the same without doing violence to its nerves and blood-vessels. 3. You have traced the adductor longus from origin to insertion, preserved its nerves, cut the origin of the muscle, and seen the anterior division of the obturator nerve lying below, on the adductor brevis muscle ; and the branches of this nerve you have followed to four muscles. 4. You have located the anterior crural nerve in a space between the psoas magnus and iliacus, taken this nerve up, and traced out its branches to the muscles on the front part of the thigh and to the skin covering these muscles and to the joints these muscles move. 5. You have removed the rectus from its bed, traced the same to its origins, and preserved the nerve- and blood-supply ; finally, you have cut the rectus four inches above the patella. 6. You have seen that the crureus is not a separate muscle, but a part of the vastus intern us. 7. You have traced the femoral artery well down and studied its profunda division. 8. You have traced the vasti and rectus to their common insertion into the tubercle of the tibia by the ligamentum patella:,. What to Dissect Next. (i) Cut the origin of the adductor brevis (Fig. 220), gently lift the same, and see the posterior division of the obturator nerve. Trace this nerve to the adductor magnus and obturator externns muscles. (2) Cut the pectineus (Fig. 219) and turn it down. Now, on the outer surface of the obturator externns muscle you will find the o bturator artery, anastomosing with the internal circumflex, a branch of the profunda. (Fig. 223.) (3) Now you may replace in this order the muscles you have cut and turned aside : (a) Pectineus, (^) adductor brevis, (r) adductor longus, (d) rectus. Place the sartorius in its original oblique position. 3 22 PRACTICAL ANATOMY. Two Important Surgical Areas. Scarpas triangle and Hunter s canal. Scarpa's triangle is located on the upper anterior one-third of the thigh. It is divided into an inner and an outer part by the femoral vessels, which bisect the space vertically. It is of surgical importance for the following reasons : 1. Inguinal and femoral herniae are seen here. 2. Varicocele, dilatation of scrotal or spermatic veins. 3. Removal of inguinal lymphatic glands may become necessary. 4. Fracture of the femur and dislocations of its head. Common iliac artery SYMPA THETIC NER VE Middle sacral artery Common iliac vein URETER Internal iliac artery External iliac vein External iliac artery Potterior branch of internal iliac dividing into gluteal and ilio-lumbar arteries Lateral sacral artery SACRAL PLEXUS OBTURATOR NERVE Obturator artery Obliterated hypngastric Superior vetical artery Edge of levator ani Pudic artery BLADDER Middle vesical artery Deep epigastric artery Pubic branch of epi- gastric artery Common femoral artery Long saphenons vein Pectineus muscle Obturator artery Adductor magnus Internal circumflex artery Adductor brevis OBTURATOR NERVE (ant. branch) Profunda artery Adductor longus, hooked aside Superficial femoral artery and vein . Oracilis muscle Lower part of sartorius Psoas muscle Ilio-lumbar artery EXTERNAL CUTA- NEOUS NERVE Iliacus muscle GE. \ITO-CRURAL NER VE ANTERIOR CRU- RAL NERVE Deep circumflex iliac artery Superficial circumflex iliac artery A.VTERIOR CRfRAL AT. Gluteal artery and Tensor fasciae femoris (hooked aside) Glutens mediuB and minimus Sartorius muscle MIDDLE CUTA- NEOUS NERVE NER VE TO RECTUS A'ERVE TO VASTl-S BXTKRXl'S External circumflex ar. XERVB TO CRl'REUS Rectus, hooked aside /. o.\("; SAPBBNO I 'S NERVE A\I) NERVE TO IMN- TUS INTERNUS Vastus internus muscle FIG. 223. TUP, FKMORAI. ARTKRY IN SCAKTA'S TKIANCI.I. (From a dissection by W. J. Wai sham in St. Bartholomew's Hospital Museum.) 5. Burrowing of pus from regions above may point here. 6. Bloodless amputation at the hip involves this region. 7. Injuries to the vessels and nerves in the space may occur. The triangle- should be studied as having tin- following geometrical parts : (I Roof: skin, superficial and deep fascia.-. (2) Floor: iliacus, psoas, pectineus, and adductor longus. (3) Superior boundary : Poupart's ligament. (4) Internal boundary : adductor longus muscle. (5) Fxternal boundary : the sartorius muscle. (6) The base: the superior boundary. (7) The apex : conjunction of adductor THIGH AND LEG. 3 Z 3 longus and sartorius. Contents : (a) The femoral sheath, formed of the iliac fascia behind the vessels, and the transversalis fascia in front of the same. This sheath contains the femoral artery, vein, and femoral canal. (Fig. 212.) (b) The termina- tion of the longsapJienous vein, (c} The external cutaneous nerve of the thigh, which you will find under the anterior superior iliac spine. (//) The spermatic cord in the male, and its homologue, the round ligament, in the female, both of which you will find under the spine of the pubes. (Fig. 224.) (e) The obturator nerve and vessels. (/) The lesser trocJianter of the femur, giving insertion to the iliacus and psoas magnus muscles ; (^) the anterior crural or femoral nerve and its branches ; (/^) the common femoral artery and vein, bifurcating into the profunda and superficial femoral arteries. In this, as in other regions, the student should become so familiar with structures that he can, by the sense of feel alone, say positively what he touches. I remember well a freshman examined the deep Obliquus interims Aponeurosis of obliquuB externus Spermatic cord Origin of cremaster Triangular fascia Insertion of cremaster Loops of cremaster Intercolumnar fibres FIG. 224. OULIQUUS EXTERNUS AND FASCIA LATA. part of Scarpa's triangle, and feeling the lesser trocJianter of the femur, made a diagnosis of osteo-sarcoma ! Poupart 's ligament, or crural arch, is the lower part of the aponeurosis of the ex- ternal oblique muscle of the abdominal wall. (Fig. 224.) It extends from the anterior superior iliac spine to the pubic spine. It is continuous below with the fascia lata. (Fig. 212.) It forms the floor of the inguinal canal, upon which floor rest the spermatic cord and round ligament of the uterus, just before they emerge through the external abdominal ring into Scarpa's triangle. Hunter s canal (Fig. 219) (i) extends from the apex of Scarpa's triangle to the aperture in the adductor magnus muscle. (Fig. 222.) In other words, it is a groove linking together the popliteal space and Scarpa's triangle. (2) It is bounded externally by the inner part of the vastus internus muscle ; internally by the front surfaces of the adductor longus and adductor magnus muscles. (3) Its roof is the deep fascia passing across from the adductors to the vastus internus. It contains : (i) The superficial femoral artery and vein. The vein lies behind 324 PRACTICAL ANATOMY. the artery, according to the rule governing the relations of veins and arteries below the diaphragm. (2) The long saphenous nerve. Note that this nerve is on the outer side of the artery. (3) The communicating branch to the obturator nerve via the subsartorial plexus. Explain the quadriceps femoris. This is a collective noun indicating a four-headed muscle, on which depends LEVEILLE 0i f.'t* FIG. 225. MU.-.CLE; OF THE ANTERIOR ASTECT <>K TIIK I'.ODY. \. Pectoralis major. 2. Its clavicular fasciculus. 3. Fasciculus attached to abdominal aponeurosi 4,4. External oblique. 5,5. Serratus magnus. 6,6. Anterior border of latissimus dorsi. 7. De cassation of tendinous fibers of pectorales majores. 8. Ensiform cartilage. 9, 9. Abdominal aponeurosis. IO, IO. Linea alba. II. Umbilicus. 12, 12, 12. Tendinous intersections of rectus abdominis. 13,13. External abdominal ring. 14. Pyramidalis. 15,15. External border of rect abdominis. 16. Sterno-hyoid. 17. Omo-hyoid. 18. Sterno-mastoid. 19. Cervical portion trapezius. 20. Deltoid. 21. Biceps brachialis. 22. Pectineus. 23. Sartorius. 24. Kectus femoris. 25. Tensor vaginre femoris. extension of the leg. The individual muscles forming the extensor quadriceps femoris all converge to form one tendon, the ligamentum patellae, which is inserted into the tubercle of the tibia. (Fig. 220.) These muscles, from their diverse origin and extensive attachments t< the- femur and ilium, represent both strength and celerity of motion not an easy combination. The rectus, vastus THIGH AND LEG. 325 externus, vastus interims, and crureus make up the extensor musculature. Trace these muscles to the following origins (from Morris) : The Rectus. Origin. Anterior head, from the front of the anterior inferior spine of the ilium ; posterior head, from the upper surface of the rim of the acetabulum just external to the attachment of the capsular ligament. Vastus Externus. Origin. (i) The upper half of the anterior intertro- Posterior limit of external oblique Insertion of external oblique Internal oblique Tensor vaginas t'emoris Rectus femoris ARTICULAR PORTION OF COTYLOID CAVITY PECTINEAL RIDGE Fectineus Rectus abdominis Pyramidalis Adductor longus Adductor brevis DESCENDING RAMUS OF PUBES Graoilis Latissirnus dorsi CREST OF ILIUM SUPERIOR GLUTEAL RIDGE OBTURATOR NOTCH Semimembranosus Quadratus femoris Semitendinosus and bicepa _ Adductor magnus RAMUS OF ISCHIUM Obturator externus FIG. 226. THE LEFT HIP-BONE. (Posterior view.) (Trace out the origin and insertion of muscles and consult this figure.) chanteric line and the front of the upper part of the femur along the anterior border of the great trochanter ; (2) a horizontal line, which forms the lower border of the great trochanter ; (3) the outer lip of the gluteal ridge ; (4) the upper half of the outer lip of the linea aspera and the adjacent portion of the shaft of the femur for about one-sixth of an inch ; (5) the external intermuscular septum in the neighbourhood of its attachment to the linea aspera. Vastus Interims. Origin. (i) The outer lip of the lower half of the linea Obturator extcrnus Gluteus rnediue TUBERCLE OF THE quadratus femoris Ligamentum teres Capsule POSTERIOR INTERTROCHANTERIC LINE Faoas LESSER TROCHANTER Iliacus Peotineus Adductor brevis INTERVENING SPACE OF THE LINEA ASPERA. Adductor longus Vastus internuB INNER LIP OF THE LINEA ASPERA NUTRIENT FORAMINA FOR FEMORAL ARTERY INTERNAL CONDYLAR LINE Adductor magnus Flantaria Oaatrocnemius Anterior crucial ligament INTERCONDYLOID NOTCH ADDUCTOR TUBERCLE Gaatrocnemius lateral ligament EXTERNAL CONOYLE INTERNAL CONDYLE Posterior crucial ligament FIG. 227. Tin I ill IIMIK. (Posterior view.) (Study the insertion of the adductor on this figure.) 326 GREATER TROCHANTER SUPERIOR CERVICAL TUBERCLE Capsule OF THE HIP-JOINT ATTACHED TO THE ANTERIOR INTERTROCHANTERIC LINE LESSER TROCHANTER Fsoas Pyriformis Obturator internua ADDUCTOR TUBERCLE Adductor magnus External lateral ligament Fopliteua INTERNAL CONDYLE EXTERNAL CONDYLE FIG. 228. THE LEFT FMUR. (Anterior view. (Study the origin of the vasti on this figure.) 328 PRACTICAL ANATOMY. aspera and its external bifurcation, together with the adjacent external inter- muscular septum ; (2) the lower part of the anterior intertrochanteric line and the spiral line of the femur; (3) the inner lip of the whole length of the linea aspera and its internal bifurcation, together with the adjacent part of the internal inter- muscular septum, and the front of the tendon of the adductor magnus ; (4) the greater part of the front and sides of the femur within the limits formed by the three preceding attachments and the origin of the vastus externus. The Physiological Adductors of the Thigh. In figure 222 this group of muscles may be seen. They are four in number. They are supplied by the obturator nerve. They are all ligamentous in action to the hip-joint ; hence the obturator nerve will send a nerve to this joint. They all figure conspicuously in the architecture of Scarpa's triangle and Hunter's canal. Study the origin ot these muscles very carefully on figure 226, and then on the cadaver, as follows : The adductor longus arises from the anterior surface of the body of the pubis immediately below the crest and angle. The adductor brevis arises from the bo'dy and ramus of the pubis, below and external to the origin of the adductor longus. If the student will study the divergence of the ischio-pubic rami, he will then understand why the origin of the adductor brevis is described as external to that of the adductor longus. The adductor magnus arises from the tuber of the ischium, and from the ischio-pubic ramus. (Fig. 226.) Examine the perforations in this muscle for the superficial femoral artery to pass into the popliteal space. Name the adductor muscles and give their insertions. (Fig. 227.) Adductor longus, inserted into middle lip of linea aspera, middle one-third. Adductor brevis, inserted into middle lip of linea aspera, upper one-third. Adductor gracilis, inserted into inner surface of tibia, upper one-third. (Fig. 216.) Adductor magnus, inserted : (i) Into the back of the femur, in a line beginning at the lower extremity of the linea quadrati, and extending along the inner border of the gluteal ridge and the middle of the linea aspera down to its bifurcation ; f t (2) into the adductor tubercle on the upper and posterior part of the internal condyle ; (3) into the lower part of the internal intermuscular septum. Fascial Septa. Having thoroughly dissected all the muscles on the inner part of the thigh and front part of both leg and thigh, I now desire you to answci these questions : 1. How many musculatures have you found that is, lioiv many groups muscles acting in unison f You say : (i) An extensor group, innervated by an extensor nerve, called an- terior crural or femoral ; (2) a flexor group, on the posterior part of the thigh, innervated by a flexor nerve, called the great sciatic ; (3) an adductor group, on the' inner part of the thigh, innervated by an adductor nerve, called the obturator ; (4) an abductor group, on the outer side of the pelvis, innervated by the superior gluteal, an abductor nerve ; (5) * group OH t lie front of the leg flexors of the tarsus and extensors of the toes supplied by the anterior tibial nerve ; (6) a group on the outer surface of the fibula, supplied by the muscular branches of the musculo-cuta- neous nerve ; (7) two groups of muscles on the posterior part of the /eg, innervated by the internal popliteal nerve, extensors of the tarsus and flexors of the toes. 2. Are the groups individually separated from eaeli other by septa f You answer yes, for you have found a fascial septum between the adductors and extensors ; between the flexors and adductors ; between the anterior and lateral groups below the knee ; between the lateral and posterior groups ; be- tween the superficial and deep groups on the back of the leg. 3. Arc these intermuscular septa attached to bone f Do they in any manner origin to muscle .' Are they derived from deep fascia f You answer the above in the affirmative, , THIGH AND LEG. 329 Anatomical transition is never abrupt, but gradual. Compact bone-tissue gradually merges into cancellous ; muscle gradually becomes tendinous ; at muco-cutaneous areas skin and mucous membrane gradually partake of the nature of each other. The transition from extension of the leg to adduction of the thigh would be abrupt. This is moderated by the sartorius muscle, which, in consequence of its dual function, has a double nerve-supply and an indepen- dent fascial sheath. The adductor magnus moderates between flexion and adduction ; hence its dual nerve-supply. The Femur (Figs. 227 and 228). Name the points of the femur of impor- tance in practical anatomy. The head articulates with the acetabulum. The neck joins the head of the bone to the shaft. The greater trochanter facilitates axial rotation. The lesser trochanter facilitates axial rotation. The tereal depression is for the ligamentum teres. The digital or trochanteric fossa is for the obturator externus. The intertrochanteric lines are anterior and posterior. The oblique line of the greater trochanter is for the gluteus medius. The anterior intertrochanteric line is for the capsule. The tip of the greater trochanter is for the gemelli, pyriformis, obturator ex- ternus. The condyles articulate with the tibia and patella. The condylar ridges limit laterally the popliteal surface. The intercondylar notch lodges the crucial ligaments. The patellar facet articulates with the patella. The adductor tubercle is for the adductor magnus tendon. How and ivJicrc are (lie glntcal muscles inserted / They are inserted principally by tendon as follows : The gluteus maximus into the gluteal ridge ; the gluteus medius into the oblique line of the greater trochanter ; the gluteus minimus in the anterior border of the greater tro- chanter. What is the third trochanter / A name given to the gluteal ridge when this is unusually prominent. Growth is the correlative of function ; where extraordinary function is imposed on any group of muscles, or on any single muscle of a group, the bony insertion point of the muscle will be correspondingly increased in size. Trochanter means a bony eminence for muscular attachment, situated favorably for axial rotation of the limb ; hence the name, third trochanter. Describe the line a asp era. This may be compared to a tree with (i) a trunk, (2) definite roots, (3) definite branches above. Now, when we speak in general terms of a tree, we have in mind the trunk ; when we speak specifically of this object as a shade-tree, we have in mind the branches ; when we speak specifically of its attachments to the earth, we have in mind the roots of the tree. The linea aspera has a trunk which is in the middle one-third of the femur ; branches which ramify definitely in the upper one-third of the femur; roots which are definitely disposed in the lower one- third of the femur. Describe the trunk of the linea aspera. It is composed of three lips or ridges, produced by muscular traction ; these lips are called outer, middle, inner. This part of the linea aspera occupies the middle one-third of the shaft of the femur, and forms the posterior border of the same. How is the root of the linea aspera disposed f The outer lip is continued downward and outward to the condyle of the 330 PRACTICAL ANATOMY. , femur as the external condylar ridge. The inner lip is continued downward to the adductor tubercle as the internal condylar ridge. The middle lip is continued downward, and expands to form the popliteal surface of the femur. Hou arc the branches of the linen aspera disposed / The inner lip continues upward, around and below the lesser trochanter, as the spiral line ; to the lower half of this spiral line is attached the vastus externus ; to the upper, the capsule of the hip-joint. The outer lip of the linea aspera continues upward and outward, and ends at the base of the great trochanter in the gluteal ridge for the gluteus maximus. The middle lip divides into an inner and an outer division. The inner breaks up into two branches, one for the iliacus, the other for the pectineus muscle, both of which continge the lesser trochanter. The outer division of the middle lip of the linea aspera terminates above as a vertical ridge, midway between the trochanters, as the linea quadrati, for the insertion of the quadratus femoris. Describe the attachment of muscles to the three lips of the trunk of the linea aspera. To the outer, the short head of the biceps femoris and the vastus externus ; to the inner lip, the vastus internus ; to the middle lip, the adductor brevis, adduc- tor longus, and adductor magnus. THE PELVIC OUTLET. Locate : (i) The subpubic arch ; (2) the tuberosities of the ischium ; (3) the tip of the coccyx ; (4) the ischio-pubic ramus on each side, and give its com- position ; (5) the spine of the pubes ; (6) the symphysis pubis. ' Place the subject in the position shown in figure 229 /. e. } flex the leg on the thigh, the thigh on the abdomen, and abduct the thighs. Now fill the rectum with cotton and sew the margins of the anus together. Do not take your stitches too deeply one-fourth of an inch external to the junction of the skin and mucous membrane is enough. Incisions. (i) Cut from the subpubic arch through the skin to the front margin of the anus ; then from the posterior margin of the anus to the tip of the coccyx ; (2) cut from one tuberosity of the ischium to the other ; (3) make a circular incision around the anus just a little outside of the stitches employed in sewing together the margins of the anus ; (4) now begin, and dissect back the four flaps. The greatest care must be taken to keep the skin very thin thin enough to see through. You have now removed the skin from the outlet of the pelvis. This space is diamond in shape, and has the following boundaries : Two lines above and two below will outline the space called the pelvic outlet (i) a line from the tuberos- ity of the ischium to the subpubic arch on each side above ; (2) a line from the tip of the coccyx to the tuberosity on each side below. This outlines two triangles with their bases together on an imaginary line from one tuberosity to the other. The anterior triangle is called the permeal ; the posterior, the ischio- rectal. Continue removing skin until yon have exposed a space as lar^e as that represented in figure 229. The next step is to introduce a sound into the bladder, and retain it there by means of string tied tightly around the penis near the end. A dissection of this region really consists of only two stages: (i) Of the THIGH AND LEG. 33 1 structures seen in figures 229 and 230; (2) of structures seen in figure 233. After having removed the skin, only a little developing is necessary to expose all the structures seen in figures 229 and 230. To give an adequate idea of the subject, study the following to learn what you are expected to find in the first stage of the dissection : 1. The deep layer of the superficial fascia that you see in figure 230 turned outward and marked Colics' fascia. Notice this is attached to the ischio-pubic ram us and to the triangular ligament, whose cut edge shows in figure 230. This is called the fascia of Colles. 2. Around the anus you will see a very delicate layer of muscular fibres that BUL80-CAVERNOSUS Superficial triangular ligament ISCHIO-CAVERN03U8 INFERIOR PUDENDAL NERVE .-ri'j-i:i-ir/AL I'KI;I.\\EAL NERVE INFERIOR llJEMOHIilfOIUAL NERVE CUTANEOUS BRANCH OF FOURTH SACRAL Gluteus maximus TUBEROSiTY OF ISCHIUM Great sacro-sciatic ligament Levator ani Superficial transveraua perinaei Sphincter aui FIG. 229. THE MALE PERINEUM. (Modified from Hirschfeld and LeveillS.) throws the margin of the anus into folds the corrugator cntis ani, a dermal muscle. 3. In the anterior triangle you see the three large pyramids originating, \\hich come together to form the penis: (i) The bulb in the centre, being the lower part of the corpus spongiosum ; (2) the crura, parts of the corpora cavernosa on each side, in firm connection with the ischio-pnbic rand. 4. The bulb, covered by a muscle called the accelerator nriwc in the male. Depress the sound and you can make this bulb stand out very prominently. (Fig. 230.) 5. Tlie cms penis, covered by a muscle called the erector penis ischio-cavern- 33 2 PRACTICAL ANATOMY. osus in the male. Pull the penis upward and from side to side gently, and this will bring the crura and their investing muscles into view. (Fig. 239.) 6. The external spliineter aid you will see reaching from the tip and sides of the coccyx, surrounding the anus, to the central perineal point. The outer margins of this muscle seem to become lost in a quantity of fatty and connective tissue. 7. Another muscle, the superficial transversns perilled, lies between the sphincter ani and the erector penis, extending in an oblique direction from the tuberosity of the ischium to the central perineal point. 8. Tlie central perineal point, or tendinous centre of the perineum, is in the mid-line from side to side and about one inch in front of the anus. As you will Superficial perinceal vessels Accelerator urinae Colles'B fascia, turned back Erector penis Transverse perinceal vessels Cut edge of triangular ligament SUPERFICIAL PERIXJEAL NERVE GIVING OFF TRA NS VERSE BRA NCH Pudic vessels Inferior hamarrhoidal vessels and nerves Glutens maximus hooked back Dorsal artery of penis Artery of crus Great sciatic ligament Levator ani External sphincter FIG. 230. THE ARTERIES OF THE PERINEUM. On the right side Colics' fascia has been turned back to show the superficial vessels. On the left side the superficial vessels have been cut away with the anterior layer of the triangular ligament to show tin- deep vessels. demonstrate in your dissection, and as you may see in figure 229, this point is where the following muscles meet: (i) The sphincter ani ; (2) the superficial transversus perinaei ; (3) the accelerator urinae or bulbo-cavernosus. 9. The levator ani shows well in both figures, but at this stage of the dissec- tion is obscured by (i) the sphincter ani and (2) the large mass of fat in the ischio-rectal fossa. The muscle is seen in figure 230 on each side of the anus. 10. The space on each side of the anus is the ischio-rectal fossa. It is now full of fat. Figure 230 shows this fat removed and the levator ani muscle divested of the anal fascia. 1 1. The greater saero-seiatie ligament must now be located. In the figures it is shown cut on one side to expose the internal pudic structures. 12. Notice the luzmorrhoidal branches t ami the perineal branches of the internal THIGH AND LEG. 333 pudic vessels and nerves ; also the inferior pudendal nerve, a branch of the small sciatic, distributed to the scrotum and side of the thigh. Dissection. Locate the greater sacro- sciatic ligament. Cut this ligament and find under the same, in the lesser sacro-sciatic foramen, the main branches of the internal pudic nerve and vessels. You will find two fair-sized branches given off. Tuey will both be found to break up into numerous branches. Now carefully trace these branches through the fat of the iscldo-rectal fossa the one to the anus, the other forward to the perineum. The branch to the anus is the inferior li&morrhoidal ; the other is the superficial perineal. Notice: (i) These branches are both from the internal pudic ; (2) each divides into cutaneous and muscular branches, for the supply of the muscles and the skin in these regions. The arteries follow the nerves and take the same name. The internal pudic nerve now continues in a canal called Alcock's. This nerve pierces the posterior layer of the triangular ligament (Fig. 233), and gives off the following branches : (i) The dorsal nerve of tlie penis ; (2) nerve to the bulb ; (3) nerve to the corpus cavernosum ; (4) superficial perineal. This, the dorsal nerve of the penis, is the largest division of the internal pudic nerve. You will find it on the inner sur- face of the ramus of the ischium. It passes behind the superficial transversus Superficial dorsal vein of penis /Deep dorsal vein Dorsal artery TUNICA ALBUGINEA Vessels TUNICA ALBUGINEA Artery Artery URETHRA CORPUS SPONGIOSUM FIG. 231. TRANSVERSE SECTION THROUGH THE BODY OK THE PENIS. perinaii muscle, gains the deep perineal space, pierces the anterior layer of the deep perineal fascia, and is distributed to the dorsum of the penis. Crus Penis (Dissection of] and Its Muscle the Erector Penis, or IscJiio-cavern- OS j {Sf The muscle covers the crus. Cut through the centre of the muscle in the long diameter and turn the two halves aside. Notice its extensive origin : (i) Tuberosity of ischium, (2) ramus of ischium, (3) surface of the crus. Trace the muscle up to its insertion into the sides and under surface of the crus ; also notice its nerves and vessels. Now cut through the thick, strong capsule of the crus in its long diameter, and examine the erectile tissue of its interior. This tissue is the specific element of the crus, and is called, in common with the remainder of the lateral pyramid of the penis, the corpus cavernosum. Observe the strong origin of the crus from the ischio-pubic ramus. Dissection of Accelerator Urimc and the Bulb. Depress the sound and make the bulb, covered by the accelerator, stand out full. This muscle, as you see, is in the mid-line, in front of the anus. The muscle being on the stretch, you will now see in the middle a raphe separating the two halves. Now cut, with a very sharp knife, through the center of this raphe and turn the muscle outward, and thus expose the bulb. (Fig. 230.) Trace the muscle and note its insertions : (i) 334 PRACTICAL ANATOMY. Tlie lowest fibres into the triangular ligament; (2) the middle, surround the bulb ; (3) tlie upper ones pass out across the corpus spongiosum and are inserted into the dorsum of the penis and pubic bone. Notice, also, the nerve-supply to this muscle from the internal pudic. Now cut through the bulb down to the sound and see (l) the bulbous part of the urethra and (2) the erectile tissue ; the latter is the specific element of the bulb, and, taken with the remaining part of the middle cylinder of the penis, is called the corpus spongiosum. Notice the dense fibrous capsule of the bulb, derived from the outer layer of the triangular liga- ment, upon which the bulb rests. See the nerves and vessels from the internal pudics. Dissection of Superficial Transversus Penned. Trace this little muscle from the tuberosity of the ischium to the central point of the perineum, it being inserted between the sphincter ani and the accelerator. Notice the nerve-supply. Dissection of the Penis. With the scissors cut through the mid-line of the skin of the scrotum and under part of the penis. Now.carefully remove the integu- ment from the entire organ. As stated above, the penis is composed of three- cylinders, which converge from three different sources. These three cylinders are (i) the two corpora cavernosa and (2) the urethal cylinder or corpus spongiosum, which unite to form a triangular body with three compartments. In transverse section. (Fig. 231.) See, now, that each cylinder has special char- acteristics, (i) The central cylinder, resting on the outer layer of the triangular ligament, begins in the bulb and terminates in an expansion, the glans penis, which receives the conical extremities of the lateral cylinders. (Fig. 232.) (2) The lateral cylinders, the corpora cavernosa, begin in blunt crura from the ischio- pubic ramus, are covered by compressor muscles, erectores penis, and terminate in pointed extremities in the distal expansion of the corpus spongiosum the head of the penis. Observe, also, that each cylinder has common characteristics : (i) a fibrous elastic envelope ; (2) erectile tissue. Lastly, see the middle cylinder traversed from end to end by the urethra. Now cut down on the sound and expose the urethra. (Fig. 232.) The urethra is the mucous canal extending from the bladder to the extremity of the glans penis. In its course it pierces the prostate from base to apex, the deep and superficial triangular ligaments with the intervening compressor urethrae muscle, and the whole length of the corpus spongiosum. It may hence be divided into three segments : (i) Prostatic ; (2) membranous (the portion lying in the space between the two transverse triangular ligaments) ; and (3) spongy. (Fig. 232.) Having completed the first stage of the dissection of the pelvic outlet, review your work carefully, and see if you have found the following structures : 1. You removed the skin, learned the boundaries of the pelvic outlet, and classified the same into an anterior or perinea/ portion, and a posterior or isc/iio- rectal portion. 2. You saw the deep layer of the superficial fascia, Colics' fascia, having two attachments : (i) To the ischio-pubie ramns ; (2) to the triangular ligament. 3. You located the greater sacro-sciatic ligament, cut the same, and found the main trunk of the internal pudic nerve with its accompanying vessels. In tliis locality you found two nerves given off. One of these you traced through the fat in the ischio-rectal fossa, in many branches, to the corrugator cutis ani and external sphincter ani muscles, and also to the skin covering these muscles ; this was the inferior hicinorrlmida/ nerve. The other you traced, under tin.- name of superficial peri/teal nen>e, to (i) the accelerator, (2) tin- erector penis, (3) the superficial transversus penn;ei, and to the skin covering these muscles. 4. Then you located the central point of tlie perineum, and learned the muscles meeting there and their nerve-supply as follows: (i) Accelerator urin;e ; (2) THIGH AND LEG. 335 erector penis ; (3) superficial transversus perinaii ; (4) levator ani. Nerve-supply, the internal pudic. 5. You then located the origin of the three cylinders of which the penis is composed, the central one on the triangular ligament as the bulb, the lateral ones on the ischo-pubic rami as the crura, and you studied the muscles associ- ated with these three cylinders : accelerator urinse and erector penis. URETER -4 Plica uretica SECTION OF BLADDER INTERNAL URINARY MEATUS PROSTATIC SINUS WITH OPENING OF PROSTATIC GLANDS SINUS POCULARIS FOLLICULAR GLANDS OF DORSAL WALL SEPTUM PECTINIFORME THIN LAYER OF CORPUS SPONGIOSUM ORIFICE OF COWPER'S GLAND Albuginea of corpora cavernoaa FOSSA NAVICULARIS EXTERNAL URINARY MEATUS SECTION OF PROSTATE VERUMONTANUM EJACLTLATORY DUCT PROSTATIC GLANDS MEMBRANOUS URETHRA SECTION OF CORPUS CAVERNOSUM BULBOUS PORTION OF URETHRA Mucous membrane j/ I(; . 232. THE MALE URETHRA, CLEFT DORSALI.V TO SHOW VENTRAL Mucors WALL. 6. You examined the three component cylinders of the penis ; saw the general and special characters of each. You saw each cylinder surrounded by a dense tunica albuginea and composed internally of erectile tissue. You saw the central cylinder traversed by a conduit the urethra ; you opened this urethra and studied its interior. In the cuts and in your dissections you studied both the transverse and longitudinal sections of the penis. 336 PRACTICAL ANATOMY. SECOND STAGE IN DISSECTING THE PELVIC OUTLET. Dissect the crura from the rami and turn them upward over the pubic bone and fasten them out of your way. Cut the central cylinder the corpus spongi- osum off even with the outer layer of the triangular ligament. Detach the external sphincter ani and the two superficial transverse perineal muscles at the central perineal point. Then your field will look like the leftside of figure 233. The triangular ligament (Fig. 233) occupies the space under the pubes. It consists of two layers, superior and inferior, also called superficial and deep tri- angular ligaments, between which are found : (i) The membranous urethra (Fig. 232) ; (2) the duct of Cowper's gland perforating the superficial triangular ligament (Fig. 233) and opening into the bulbous urethra (Fig. 232); (3) the dorsal nerves and vessels of the penis perforating the suspensory ligament of the penis and supplying the back of the penis (Fig. 233); (4) the deep transversus perinaei or compressor urethrae, the muscle of Guthrie. (Fig. 234.) The above structures are seen on removing the inferior layer of the triangular Subpubic ligament with aperture for dorsal vein of the penis Apertures for dorsal artery and ( nerve of the penis \ Crus penis Aperture for artery of corpus cavernosum Superficial triangular ligament Ischio-caveruosus, or erector penis Aperture for artery to bulb TJrethral aperture Aperture for Cow- per's duet Position of bulb Apertures for super- ficial perinceal vessels and nerve Fascia of Colles, turned backwards DORSAL NERVE Anterior layer of triangular ligament Dorsal artery of penis Deep triangu- lar ligament Artery of carpus cavernosum Artery to bulb J'n formed by the obturator interims muscle and the innominate bone. This muscle is covered by a dense fascia of the same name. This fascia splits to form a canal (Alcock's) in which are the internal pudic vessels and nerve. TIic inner wall of the ischio-rectal fossa is formed by the levator ani and coccygeus muscles. These, as you will see, embrace the rectum and give it sup- port. The levator ani muscle arises from the white line. This line extends from the spine of the ischium to the pubic bone. The obturator fascia delaminutcs at the white line, and gives origin to the levator ani muscle in the split between the upper and lowrr branches into which it divides. The apex, then, of the fossa is at the white line. The boundaries, as you will now see them on your work, of tin- inlet of the fossa are: (i) The external sphincter ani; (2) the superficial transversus perinaei ; (3) the greater sacro-sciatic ligament ; (4) the glutens maxi- inus muscle; (5) the tubers of the ischium. The base of the fossa is the skin THIGH AND LEG. 337 and fasciae covering the inlet. The fossa extends in an upward direction to the pubic bone ; in a backward direction to the sacrum, forming the anterior and posterior recesses of Morris. In liberating pus in this fossa, cut through the base ; then lay your knife aside and continue the operation with a blunt instrument. 1. Give tlie shape of, and tell ivJiat yon mean by, the pelvic outlet. It is lozenge-shaped, and is the space bounded by the pubic arch above, the coccyx below, and the greater sacro-sciatic ligament, tuberosity of the ischium, and ischio-pubic ramus laterally. 2. Give the subdivisions of this space, and tell zvhere the boundary -line between the two is located. A line from tuberosity to tuberosity of the ischium divides the space into an anterior triangle, the perineum, and a posterior triangle, the ischio-rectal fossa. P'IG. 234. MUSCLE OF GUTHRIE. I. Bulbo-cavernosus (accelerator urinre) muscle. 2. Muscle of Guthrie (transversus perinaei profun- dus). 3. Superficial transverse muscle. 4. Ex- ternal sphincter ani. 5. Levator ani. FIG. 235. MUSCLE OF GUTHRIE AND WILSON. i. Bulb of urethra. 2, 2. Muscle of Guthrie (transversus perinsei profundus). 3. Muscle of Wilson. 4. Transversus perin) by the veins that 340 PRACTICAL ANATOMY. accompany the arteries to the corpora cavernosa and corpus spongiosum. The dorsal vein passes under the pubic arch and is tributary to the vesico-prostatic plexus, at the base and sides of the bladder. The other veins accompany their arteries and become tributary to the internal iliac vein. 10. Describe the nerve-supply of the penis. The erectile bodies receive nerves from the dorsal nerve of the penis ; the superficial perineal and sympathetic filaments from the hypogastric plexus. The skin receives sensory branches from the genito-crural and superficial perineal. THE FEMALE PELVIC OUTLET. The surgical importance of the female perineum will warrant a thorough consideration of its dissection in this book. The homologies are so striking that some of our best text-books on anatomy seem content to refer the student to the male perineum to gain his conception of the structure of the female peri- neum. To my mind this is a most neglectful practice, since the desideratum is a practical one, involving acquisition of knowledge pending operative procedure, instead of a knowledge in the direct line of morphological research. Would the student be competent to treat the male urethra, who had studied only the clitoris from an anatomical standpoint ? Still, the penis is homologous to the clitoris, and in the male the urethra occupies the entire length of the central cylinder of the penis. Would the student be competent to remove a diseased testicle, whose anatomical knowledge was all in homologies? Again, my experience teaches me that medical students look upon the outlet of the female pelvis not from the standpoint of the morphologist. It requires study and practice to see in the fore- skin, the labia minora ; in the scrotum, the labia majora ; in the accelerator urinae, the sphincter vaginae ; in the bulb of the urethra, the bulb of the vagina ; in the spermatic cord, the round ligament of the uterus ; in the uterus mascu- linus of the prostatic urethra, the uterus of the female ; in the testicle of the male, the ovary of the female. The repair of the female perineum is seconded in point of frequency only by extirpation of diseased ovaries and tubes ; in comparison to these operations on the female, seen thousands of times by our students, I would ask our seniors. How many operations on the male perineum have you witnessed ? How many castrations have you been party to ? A student may be expert in introducing* the catheter into the male urethra, but without special knowledge he will be ai ignominious failure when he attempts to perform this operation on the female. A knowledge of the specific anatomy of the female generative organs must In- acquired by dissection ; homological studies are most useful and most necessary adjuncts. Examine before making any incisions : 1. The mons veneris, or mons pubis, the fatty elevation covered with crisp hair, surmounting the pubes. 2. The vulva is a collective noun by which all the external genitals of the female, except the mons pubis, are designated. 3. The clitoris is an erectile structure analogous to the penis. Its free extremity is the glans. It has ;i suspensory ligament and erector muscles. On each side it has a cms originating from the ischio-pubic ramus. 4. The major labia are homologous to the scrotum. They are cleft alon;^ the mid !in-(rima pudendi). They extend from the mons to the tendinous centre THIGH AND LEG. 341 of the perineum. They flatten out posteriorly into the smooth covering of the perineum. Their junction here is called posterior commissure. 5. The minor labia are homologous to the prepuce. They are cutaneous folds. They have neither hair nor fat. In the adult they are concealed by the major labia ; not so in the foetus. They are connected posteriorly by the four- chette. 6. Examine carefully the vestibule. This is a guide to the meatus urin- arius in using the catheter. It- opens into the meatus and extends from this opening to the clitoris. 7. The meatus urinarius externus is the distal end of the urethra. It is nearly an inch from the clitoris. Introduce a catheter into the bladder and feel the urethra on the anterior vaginal wall, in the mid-line and 1.5 inch in lerfgth. 8. The vaginal orifice lies in the mid-line. It is narrowed by the hymen in the virgin, and surrounded by the remains of the hymen in females who have borne children. Its homologue would be artificially produced by a vertical slit ISCHIO-HUBIC ARCH CRUS CLITORIDIS WITH ISCHIO-CAVERNOSUS BULBO-CAVERNOSUS COVERING BULBU3 YESTIBULI Superficial trian- gular ligament GLANS CLITORIDIS WITH PREPUCE PARS INTERMEDIALIS Mucous membrane *% of vestibule MEATUS URINARIUS BULBUS VESTIBULI GLAND OF BARTHOLIN Sphincter ani FIG. 237. DIAGRAMMATIC REPRESENTATION OF THE PERINEAL STRUCTURES IN THE FEMALE. through the bulb of the male urethra ; the two parts of the accelerator urinae would then be homologous to the sphincter vaginae, and the erectile tissue of the bulb to the bulbi vestibuli. 9. "The Hymen " (Fig. 238), says Morris, " has been a subject of much speculation among the learned and unlearned of all ages. Its very existence was at one time denied by many great authorities." Failure to find this in careful examination of several hundred female foetuses and young babes has caused me to ask if it be possible that the hymen is absent in females until the age when other pubal changes occur. The remains of the hymen are called car- uncnlie myrtifonnes. They surround the entrance to the vagina. Having located the foregoing nine structures, and thoroughly learned both their function and homologies, where the latter exist, you are now ready to begin a careful dissection of t\\e female pelvic outlet. Remember, there is no difference in the posterior triangular region the ischio-rectal fossa in the sexes. The differ- ences will all be found in the anterior, or perineal region. 342 PRACTICAL ANATOMY. Dissection. Place the subject in the proper lithotomy position, as described previously for dissecting the male perineum. Thoroughly remove all pubic hair. Find the following structures and dissect them in this order : 1. Tlie clitoris, homologous to the penis. 2. The labia uiajora, homologous to the scrotum. 3. The bulbo-cavernosus, homologous to the accelerator. 4. The bnlbi vcstibuli, homologous to the bulb of the urethra. 5. The gland of Bartholin, homologous to Cowper's gland. 6. The sphincter ani, the superficial transversus perincei, and superficial part of the triangular ligament. The Clitoris. The clitoris is homologous to the penis. Its size is often underestimated, because the foreskin the labia minora binds it clown so you are MONS VENERIS GUNS CLITORIDIS MEATUS URINARIUS IN VESTI8ULAR SPACE CORPUS CLITORIDIS LABIUM MAJUS LABIUM MINUS HTM EM ANUS FIG. 238. EXTERNAL GENITALS OF THE VIRGIN, \VITH DIAPIIRACM \ 1 1< HY.MIV (Sappey.) able to see only the distal end, called the glans. In the pom's the prq> covers the glans and terminates below in a frenum ; in the clitoris the prepuce terminates in the two elongated labia minora, owing to the vertical cleft of the vaginal orifice. To dissect properly this organ, grasp the glans in the forceps of your left hand, and, with the scissors in your right hand, cut the skin along the dorsum of the clitoris for an inch upward. Then you can see the corona glandi.-' and the glans clitoridis in full view. Next remove carefully the skin from tin- two crura along.the ischio-pubic ramus. You will find these crura covered by a nuiM-lc, the erector clitoridis, homologous to the erector penis. Kemove the skin from the labia majora and trace the crescentic muscular fibres of the bulbo-cavernosus muscle around the orifice of the vagina. This is tin- sphincter muscle of the vagina. The transversus perina-i and sphincter ani an THIGH AND LEG. 343 the same as in the male. The nerve- and blood-supply are precisely the same. The deep perineal fascia transmits the urethra. It is smaller than in the male, on account of the vagina. (See blood-supply on page 339.) The perineal body (Fig. 239) occupies the space between the lower part of the vagina and the rectum. It has a base, covered by skin, and an apex between the termini of its anterior and posterior surfaces. From side to side it extends from tuber to tuber of the ischium. Its posterior surface lies in front of the anterior wall of the rectum ; its anterior surface lies behind the posterior vaginal wall. Into it are attached all the muscles of the central perineal point or tendon : (i) The external sphincter ani ; (2) the superficial transversus perinaei ; (3) the VESICAL WALL CAVITY OF BLADDER Prevesical fat Deep transver- BUB perinaei LABIUM MAJUS TTnstriped muscular fibre URETHRA LABIUM MINUS Unstriped muscular flbre ANUS Internal sphincter ani Part of external sphincter ani Vessels RECTUM COCCYX Eecto-cocey- geal muscle POSTERIOR LIP OF OS UTERI ANTERIOR LIP VAGINA External sphincter ani Internal sphincter ani VAGINAL ORIFICE FIG. 239. SECTION OF THE FEMALE PELVIS. (After Henle.) This perineal body is strong; it owes its strength to elastic The perineal body is about an inch and a half in length from sphincter vaginae, connective tissue, before backward. The glands of Bartholin probably represent Cowper's glands in the male, but are more superficially placed. They are two little racemose glands, about a third of an inch long, situated one on each side beneath the lateral wall of the vestibule and behind the bulbi vestibuli. The duct, about three-quarters of an inch in length, opens immediately in front of the vaginal orifice opposite its meridian. Locate the vagina by superior and inferior limitations. 344 PRACTICAL ANATOMY. It is limited inferiorly by the introitus vaginae at the vestibule, and superiorly by its junction with the cervix uteri. Define and locate tlie utcro-vaginal forni.v. It is the highest part of the vagina ; a space surrounding that part of the cervix uteri within the vagina, and formed by the reflexion of the vaginal mucous membrane on to the cervix. The vaginal passage extends upward and backward. Its long axis extended would pass through the upper segment of the sacrum. What arc tJic anterior relations of the vagina / It is in close relation with the urethra and bladder. The ureters open into the posterior wall of the bladder, anterior to the vagina, and about an inch below the lowest part of the cervix uteri. There is a large amount of connective tissue between the anterior wall of the vagina and the bladder and urethra. Describe the posterior relations of the vagina. The vagina is in relation posteriorly with the rectum. Intervening between the rectum and posterior wall of the vagina from above downward are (i) the peritoneal cul-de-sac of Douglas ; (2) subperitoneal connective tissue ; (3) the perineal body. Describe the lateral relations of t/ie vagina. (i) The vaginal branch of the uterine artery the uterine being a branch of the internal iliac ; (2) a plexus of veins, lying at the base of the broad ligament of the uterus, communicating with the haemorrhoidal, and tributary to the internal iliac vein. Hoiv is the vaginal inlet narrowed ? By the action of the sphincter vaginae, the levator ani, and engorgement of the erectile tissue of the inlet, called the bulbi vestibuli. Describe the structure of the vaginal wall. It is composed of three coats : (i) An outer fibrous coat, a derivative of the recto-vesical fascia. In this coat you will find in some cases a beautiful plexus of veins. (2) A muscular coat, consisting of outer longitudinal fibres and an inner layer of circular fibres. The muscular coat consists of unstriped fibres. (3) A mucous coat, highly elastic, and continuous above with the mucous mem- brane of the uterus, and below with that of the vulva. Describe tlie blood-supply of the vagina. The arteries, derived from the internal iliac, from the inferior branch of the uterine, and from the external pudic branch of the common femoral artery, lie along the lateral part of the vagina and divide into anterior and posterior branches for the supply of the anterior and posterior surfaces respectively. The veins follow the course of the arteries, form a rich plexus between the inner and middle coats, and finally become tributary to the internal iliac vein. The nerve-supply of the vagina is from the hypogastric plexus, internal pudic nerve, and the fourth sacral. POSTERIOR PART OF SHOULDER, ARM, FOREARM, AND HAND. Dissection. Locate (i) the acromion process dx\& spine of the scapula ; (2) the inner and outer Jin in cral condyles ; (3) the olecranon process of the ulna; (4) the head of the radius ; (5) the inferior outer border of the clavicle ; (6) the a.vil- Coraco-acromial Pectoralis ligament minor Omo-hyoid and the transverse ligament AXILLARY BORDER Teres major SUPERIOR ANGLE Rhomboideus minor Rhomboideus major VERTEBRAL BORDER INFERIOR ANGLE Latissimus dorsi IMC. 240. THE LKI r SCAPULA. (Dorsal surface.) lary border of the scapula ; (7) the superior border of the scapula ; (8) the greater and lesser titbcrosities of the hit merits ; (9) the olecranon fossa ; (10) i the Jilnar and radial styloid processes ; (ii) the radio-carpal articulation ; (i 2) the metaearpo- 23 345 346 PRACTICAL ANATOMY. plialangeal articulation ; (13) the phalangcal articulations; (14) the clefts of tlic fingers ; (15) the thcnar and JiypotJicnar eminences. Incisions. (i) From the acromion process to the end of the middle finger ; (2) from the outer one-third of the clavicle to the acromion process, thence along the scapular spine ; (3) from one condyle to the other. Dissection (Figs. 241 and 242). Carefully remove the skin and find the : 1 . Radial nerve distributed to three and one-half fingers dorsally. 2. Ulnar dorsal branch to one and one-half fingers dorsally. 3. External cutaneous, a branch of the musculo-spiral nerve. 4. Internal cutaneous nerve from the inner cord of the brachial plexus. INTERNAL CUTANEOUS OF MUSCULO- SPIRAL INTERS A L CUTANEOUS PALMAR CUTANEOUS OF MEDIAN PALMAR CUTANEOUS OF ULNAR SUPRA- ACROMfAL CIRCUMFLEX TWIG OF INTERNAL CUTANEOUS EXTERNAL CUTANEOUS OF MUSCULO- SPIRAL SUPRA- ACROMIAL FLEX MUSCULO- CUTANEOUS EXTERNAL CUTANEOUS OF MUSCULO- SPIRAL MUSCULO- CUTANEOCii RADIAL PALMAR CI'TANEOUS OF RADIAL FIG. 241. DISTRIBUTION OK CUTANEOUS NK.KVKS ON TIIK ANTKRIOR AND POSTERIOR ASPECTS OF THE SUPERIOR EXTRKMITV. 5. Lesser internal cutaneous or the nerve of Wrisberg. 6. Internal cutaneous nerve, a branch of musculo-spiral. 7. Cutaneous branches of the circumflex nerve to skin of deltoid. 8. Supraacromial, a descending branch of the cervical plexus. 9. Intercosto-humeral nerve the lateral cutaneous branch of the second intercostal nerve. General directions only can be give (i) Keep close to the skin when you Mar- in ally, you will see the name of the nerve, which, having found, take your forceps and search in the superficial fasdu of the region until you find the nerve. for doing this cutaneous dissection : remove it. (2) Consult the figures. SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 347 (3) Then lift the nerve on your finger and follow the same by dividing the'con- nective tissue in the direction of the branches given off. Remember that the circumflex nerve sends its cutaneous branches to the skin over the insertion of the deltoid, according to Hilton's law. (Fig. 241.) The musculo-cutaneous nerve sends a cutaneous branch to supply the skin over the insertion of the supinator longus, according to the same law, since this muscle is one of the forearm flexors and is supplied by the musculo-cutaneous. The DORSAL BRANCH OF ULNAR BRANCH OF MEDIAN NERVE BRANCH OF MUSCULO-SPIRAL RADIAL NERYE FIG. 242. A DISSECTION OF THE CUTANEOUS NERVES ON THE DORSAL ASPECT OF THE HAND AND FINGKRS. (H. St. J. B.) The branches of the median nerve are shown in black. distribution of the radial nerve is explained in the same way. You will note that the cutaneous nerves divide into numerous small branches. (Fig. 242.) The deep fascia is quite heavy below the elbow, but thin above the elbow. Opposite the wrist it takes the name posterior annular ligament. Notice in figure 243 that the muscles all become tendinous before they reach this ligament. Remove the deep fascia as in the figure. "Dorsal fascia" is the name for the deep fascia on the back of the hand. 348 PRACTICAL ANATOMY. CLASSIFICATION OF MUSCLES ACCORDING TO FUNCTION. ( i. Extensor longus pollicis ; insertion, base of second phalanx. Extensors of the pollux \ 2. Extensor brevis pollicis; insertion, base of first phalanx. I 3. Extensor ossis metacarpi pollicis; insertion, base of metacarpal. I i. Extensor carpi radialis longior ; insertion, base of second meta- Ex tensors of the carfius -: ,- ' j i u L r i. j ) 2. Extensor carpi radialis brevior; insertion, baseof third metacarpal. v 3. Extensor carpi ulnaris; insertion, base of fifth metacarpal. / i. Extensor communis digitorum ; insertion, base of second and extensors of t e tgt s -< 2 j xtensor m innni digiti ; insertion, with extensor communis. l. 3. Extensor indicis digiti ; insertion, with extensor communis. Extensors of the forear,,. \ [' The triceps ; insertion, into the olecranon process of the ulna. ( 2. The anconeus ; insertion into the oblique line of ulna. f i. Brachio-radialis ; insertion, base of styloid of radius. Supinator of the radius -, 2. Supinator radii brevis ; insertion, posterior and external surfaces (. of radius. Dissection. Trace out the tendons of the three extensors of the thumb by cutting through the deep digital fascia. Take each to its insertion according to insertions given in the classification above. Do not cut the annular ligament. See if two compartments in the annular ligament transmit the three thumb extensors. Extensor Carpi Radialis Longior and Brevior. Locate the insertions of these tendons, in the bases of the second and third metacarpal bones respectively on the radial side. Trace the same upward, under the annular ligament, and behind the three extensors of the thumb. (Fig. 243.) The extensor communis digitorum sends a tendon to each finger. The tendon of the extensor communis digitorum to the index finger is joined by the tendon of the extensor indicis; the tendon to the little finger, by the tendon of the extensor minimi digiti. Demonstrate this on your dissection. The insertion of the extensor tendons is as follows (Fig. 243) : The extensor tendon of each finger divides into three parts, opposite the first phalangeal articu- lation (Fig. 244) ; the middle portion is inserted, just across the joint, into the base of the second phalanx ; the two lateral portions pass the joint, unite on the dorsum of the second phalanx, and pass to the base of the third phalanx, where they are inserted. See whether this muscle and the extensor indicis occupy the same compartment under the annular ligament. Now trace the extensor minimi digiti through a separate compartment in the annular ligament. (Fig. 244.) Insertion of the extensor carpi ulnaris : Cut down on its tendon near the base of the fifth metacarpal ; follow the tendon through a groove behind the styloid process of the ulna, and trace it through a separate compartment in the posterior annular ligament. Compartments of the Posterior Annular Ligament (Fig. 244). Cut through the annular ligament and find the following compartments and then- contents, and see whether the same are lined by synovial membrane. 1. For extensor ossis metacarpi pollicis and extensor brevis pollicis. 2. For extensor carpi radialis longior and brevior. 3. For extensor longus pollicis. 4. For extensor communis digitorum and extensor indicis. 5. For the extensor minimi digiti. 6. For the extensor carpi ulnaris. The Brachio-radialis, or Supinator Radii Longus. Supinate the radius and you will find this muscle, on the radial side, inserted into the- base of the styloid process of the radius. (Fig. 246.) SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 349 Trace to their origins the radial group of muscles : i . Supinator longus, to upper two-thirds of external condylar ridge of the humerus. (Fig. 246.) Biceps Brachialis anticus Brachio-radialis .Extensor carpi radialis lougior Extensor communis digitorum Extensor carpi radialis brevior Extensor ossis metaearpi pollicis Extensor brevis polhcid Extensor longus pollicis Triceps Flexor carpi ulnaris Extensor carpi ulnaria Extensor minimi digiti ULNA FIG. 243. MUSCLES OF THE RADIAL SIDE AND THE BACK OF THE FOREARM. 2. Extensor carpi radialis longior, trace to the lower one-third of external condylar ridge of the humerus. 3. Extensor carpi radialis brevior, to the outer condyle of the humerus. To do this properly, begin with the tendon and follow it upward, dividing the PRACTICAL ANATOMY. connective tissue between the muscle and the ones on each side of it. Be careful, in doing this, not to destroy the vessels and nerves ; these structures will become numerous in the region of the elbow. Trace these adjacent muscles also up to their origin. Extensor oasis metacarpi pollicis Extensor carpi ulnaris Extensor communis digitorum Extensor minimi digit! Extensor indicia Attachment of extensor oommunis digitorum to second phalanx Attachment of extensor communis digitorum to third phalanx FIG. 244. TENDONS UPON THE DOKSIM 01 THE HAND. Trace the superficial group to origin as follows (Fig. 243) : 1. Extensor communis digitorum to the outer condyle of the humerus. 2. Kxtensor minimi digiti to the outer condyle of the humerus. 3. Kxtensor carpi ulnaris to the outer condyle of the humerus. Notice the triple origin of the- extensor carpi ulnaris: (i) The outer con- SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 351 dyle ; (2) the posterior surface of the ulna ; (3) posterior border of the ulna, in common with the flexor carpi ulnaris. Dissection of this latter muscle requires care. The deep group of muscles and their origin (Figs. 245 and 246) : i. The extensor longus pollicis ulna and interosseous membrane. Supinator brevis Extensor oasis metacarpi pollicis Extensor brevis pollicis Extensor longus pollicis Radial extensors Flexor carpi uliiaris Flexor profundus digitoru Extensor indicia Extensor oarpi ulnaria FIG. 245. THE DEEP LAYER OF THE BACK OF THE FOREARM. 2. The extensor brevis pollicis radius and interosseous membrane. 3. The extensor ossis metacarpi pollicis radius interosseous membrane and ulna. 4. The extensor indicis from the ulna. In view of the special importance of the three extensors of the thumb and the 35 2 PRACTICAL ANATOMY. index finger, it is necessary for the student to trace each muscle to its specific origin and insertion according to the following scheme for aiding the memory : The extensor indicis (Fig. 245') arises practically from the posterior surface of the lower one-third of the ulna and interosseous membrane. Demonstrate on the cadaver the amount of ulnar surface in the lower third of the bone which Triceps Lower limit of orbicular ligament Grooves for extensor ossis, and extensor primi internodii pollicis For extensor carpi radialis longior and brevior Extensor secundi interuodii pollicis Extensor primi interuodii pollicis SUBCUTANEOUS SURFACE Extensor ossis metacarpi pollicis AN APONEUROSIS IS ATTACHED TO THIS BORDER FROM WHICH THE flexor AND extensor carpi vliaris, AND flexor profundus digitorum ARISE Extensor sccundi internodii pollicis ULNA Extensor indicis Extensor minimi Extensor carpi ulnaris Internal lateral ligament Extensor communis digitorum Posterior Posterior radio-ulnar ligament and extensor indicis radio-carpal ligament FIG. 246. THE LEFT ULNA AND RADIUS. (Postero-external view.) does not give origin to this muscle. Observe, too, the septal origin of the muscle, between this and the extensor longus pollicis. Now consider the origins of the three' extensors of the thumb in reference to : (i) The posterior surface of the radius ; (2) the posterior surface of the ulna ; (3) the posterior surface of the interosseous membrane. Notice, too, you have to deal with a long hone, the ulna ; a short bone, the radius ; and an interosseous SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 353 membrane associated with both bones. For purposes of convenience call the extensor ossis metacarpi pollicis the strong muscle. Then say : 1. The long muscle (the extensor longus pollicis) arises from the posterior surface of the long bone (the ulna) and the interosseous membrane. 2. The short muscle (the extensor brevis pollicis) arises from the posterior Articular branch of superior projundu Braehialis anticus Supinator longus, cut Common extensor tendon Extensor carpi radialis longior and brevior Supinator brevis Posterior inlerosseous artery Extensor osais metacarpi pollicis Supiuator longus, cut Extensor primi iuternodii polUcis Posterior annular ligament Extensor carpi radialis longior Radial artery Dorsal is pollicis artery Extensor secundi internodii pollicis First dorsal interosseous muscle Dorsalis indicis artery Pnnceps pollicis artery Dorsal digital artery Triceps Rete over olecranon Inlerosseous recurrent artery Ancoueus, cut Extensor carpi ulnaris Flexor carpi ulnaris Origin of extensor secundi and indicator Posterior branch of anterior inlerosseous artery Interosseous membrane Posterior ulnar carpal artery Extensor carpi radialis brevior Posterior radial carpal artery Third dorsal interosseous artery Second dorsal inlerosseous artery Melacarpal or first dorsal interosseous artery \J Vt_>' FIG. 247. THE BACK OF THE FOREARM, WITH THE POSTERIOR INTEROSSEOUS ARTERY AND BRANCHES OF THE RADIAL AT THE BACK OF THE WRIST. (From a dissection in the Hunterian Museum.) surface of the short bone (the radius) and the interosseous membrane. Insertion into the base of the first phalanx. 3. The strong muscle (the extensor ossis metacarpi pollicis) arises from the posterior surfaces of both the long and short bones (ulna and radius) and the interosseous membrane. Insertion into base of metacarpal bone. 354 PRACTICAL ANATOMY. Observe that the collective origin of the three thumb extensors practically occupies the middle posterior third of ulna, radius, and interosseous membrane. Compare the origins of these muscles as you find them on the cadaver, with the origins as indicated in figure 246. Now locate ( i) the posterior interosseous artery. (Fig. 247.) It lies between the superficial and deep groups of muscles. It is a branch of the common inter- osseous branch of the ulnar. Find the space between the oblique ligament and the interosseous membrane, where this vessel appears. Also find where it anasto- moses with the anterior interosseous artery below. Notice that in its course this artery crosses the deep group of muscles, and is attended in a part of its course only by the posterior interosseous nerve. Trace branches from this artery to all the muscles in this locality. This artery is attended by the posterior interosseous nerve in the upper part of its course. Show the exact relation of artery and nerve- on your work. (2) Locate the radial artery in the pulse region of the wrist. You FIG. 248. THE DORSAL INTEROSSEI. will find it passing under the three extensor muscles of the thumb, where it pierces the first interosseous muscle and disappears into the deep palm. The Dorsal Interosseous Muscles (Figs. 247 and 248). Study the muscles and their blood-supply. Find four of these muscles. Notice that they arise by two Heads from the contiguous surfaces of the metacarpal bones. Trace their tendons of insertion to the tendon of the extensor communis digitorum. These muscles (Fig. 248), as you might infer from their insertion, acting alone, are abductors of the fingers. Acting with the palmar interossei and lumbricales, they produce flexion at the metacarpo-phalangeal and extension at the phalan- geal articulations. Acting in this way, they place the fingers in position for hold- ing the pen. These muscles arc all supplied by the ulnar nerve. The Supinator Radii Brevis. Detach all the muscles that arise from the outer comlylc : The extensor carpi radialis brevior, the extensor communis digitorum, the extensor minimi digiti. and the extensor carpi ulnaris. Do this SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 355 in such a way as not to injure the nerve-supply from the musculo-spiral. Now pull these muscles slightly aside and see the supinator brevis. (Fig. 247.) Trace it to the following origins and insertions : Origins. (i) Lower and back part of external condyle ; (2) the external lateral ligament of the elbow-joint; (3) the orbicular ligament; (4) the triangular depression below the lesser sigmoid cavity of the ulna, especially along its pos- terior margin, which forms the upper part of the external border of the ulna. Insertion. (i) The back of the neck of the radius; (2) the anterior and outer surfaces of the radius above and at the upper border of the oblique line. You will now find the posterior interosseous nerve issuing from the lower border of the muscle. This nerve supplies all the muscles in this region except the radial group, which were supplied by the musculo-spiral, before this nerve divided into the radial and posterior interosseous. The radial nerve is a branch of the musculo-spiral. The radial nerve perforates the deep fascia, between the extensor carpi radialis and supinator longus about three inches above the carpus. Find where the nerve comes through the deep fascia and trace the same to the dorsum of the hand, and to three and one-half fingers. The anconeus (Fig. 245) arises from the back part of the outer condyle. It is inserted into the olecranon and posterior surface of the ulna. Remove this muscle from its attachment, turn the same aside, and see the orbicular ligament of the radius and the elbow-joint. Cut through the orbicular ligament and dislocate the head of the radius. The region of the shoulder (Fig. 249) shows : 1. The deltoid muscle and its nerve-supply, the circumflex. 2. The supraspinatus muscle (Fig. 251) under the trapezius. (Fig. 250.) 3. The infraspinatus muscle under the deltoid aponeurosis. 4. The teres minor muscle, from the axillary border of scapula. 5. The triceps muscle and its three heads. 6. The teres major muscle, with the latissimus dorsi. 7. The triangular space and the dorsalis scapulae artery. 8. The quadrangular space and its circumflex structures. 9. The circumflex nerve and vessels in the quadrangular space. O. The anterior and posterior circumflex arteries and veins. 1 1. The musculo-spiral nerve and the superior profunda artery. 12. The scapular head of tJie triceps muscle between the tereals. The circumflex quadrangular space (Fig. 249) is bounded : (i) Externally by the surgical neck of the humerus ; (2) internally by the long or scapular head of the triceps ; (3) superiorly by the teres minor ; (4) inferiorly by the latissimus dorsi and teres major muscles ; (5) contents : posterior circumflex artery, a branch of the axillary, and the circumflex nerve, from the posterior cord of the brachial plexus. The triangular space (Fig. 249) is bounded : (i) Externally by the scapular head of the triceps ; (2) superiorly by the teres minor ; (3) inferiorly by the teres major and latissimus dorsi ; (4) contents (Fig. 249) : arteria dorsalis scapulae, a branch of the subscapular artery. A second triangular space is bounded (Fig. 249): (i) Externally by the humerus and outer humeral head of triceps ; (2) internally by the scapular head of the triceps ; (3) superiorly by the teres major and latissimus dorsi ; (4) it contains the musculo-spiral nerve, from the posterior cord of the brachial plexus, and the superior profunda artery, a branch of the brachial ; (5) it transmits the external cutaneous branch of musculo-spiral nerve. Dissection. The Deltoid Muscle (Fig. 250). Develop the posterior border of this muscle by cutting freely with the scissors the deltoid aponeurosis between 356 PR A CTJCA L AN A TOM \ '. this muscle and the triceps, teres minor, infraspinatus, and trapezius below. Now, with a sharp scalpel cut the scapular origin of the deltoid, along the whole length of the inferior border of the spine and acromion process of the scapula. (Fig. 249.) Turn the muscle forward and see, in a mass of connective tissue and fat, the posterior circumflex artery and circumflex nerve emerging from the quadrangular space. (Fig. 249.) Trace the circumflex nerve to the deltoid and teres minor muscles. Trace the deltoid to its insertion into the deltoid depres- sion on the outer surface of the humerus, middle one-third. Take note of the triangular shape of a number of muscles about the shoulder. The Teres Major and Latissimus Dorsi (Figs. 250-253). Divide the connective tissue between these two muscles. Trace them under the scapular Infra-spinatus, cut ACROMIAL PROCESS Suprascapular artery SPINE OF SCAPULA Teres minor Superior profunda artery Posterior circumflex artery I Deltoid, reflected Infra-spinatus, cut Teres major Dorsal scapular artery Branch of dorsal scapular arferi/ '\l-:it\'E TO TERES MINOR 'SCI Y, O-SPIRA L NER VE Outer head of triceps EXTERN. \ I. (TT.i NEO US BKAM'II <,! MUSCULO- xriU.il. NERVE Lone head of triceps CUTANEOUS BRANCH OF CIRCUMFLEX NERVE, ( IT FIG. 249. THE POSTERIOR CIRCUMFLEX ARTERY. (From a dissection by Mr. Horner in the Museum of St. Bartholomew's Hospital.) head of the triceps to the humerus. These muscles form the lower bourn of both the quadrangular and triangular spaces. They are inserted as follous : The latissimus dorsi into the bottom of the bicipital groove as high as the lesser tuberosity of the humerus ; the teres major into the inner lip of the bicipital groove for two inches in length. Note that both these tendons are inclosed in a rather tough sheath of connective tissue. The teres minor (Figs. 251 and 253) is separated near the humerus from the teivs major by the scapular head of the triceps. Divide the connective tissue between the teres minor and the infraspinatus above and the teres major below. (Fig. 250.) The teres minor arises from the axillary border of the scapula. It is synergistic in its action to the deltoid and derives its nerve-supply from the same circumflex nerve. It is inserted into the lowest facet of the SHOULDER, ARM, FOREARM, II AA r D. POSTERIOR PART. 357 Triceps Teres minor Infraspinatus Teres major Rhomboideus major Peotoralis major Oluteus medius Gluteus maximus V\<;. 250. FIRST LAYER OF THE MUSCLES OF THE BACK. 358 PRACTICAL ANATOMY. greater tuberosity of the humerus. (Fig. 253.) Demonstrate the quadrangular and triangular spaces according to the outline given in the preceding pages. (Fig. 251.) The Infraspinatus (Fig. 251). Now cut this muscle at its insertion into the middle facet of the greater tuberosity ; turn the same backward, taking care not to injure the capsule of the shoulder-joint and the vessels and nerves that enter under the surface of the muscle. This muscle arises from the outer two- thirds of the infraspinous fossa. (Fig. 252.) It is covered by a dense layer of Supra-spinatua Infra-spinatua Teres minor Teres major Long head of triceps Outer bead of triceps Inner bead of triceps FIG. 251. BACK VIEW OK THE SCAPULAR MUSCLES AND IK deep fascia. The muscle is triangular in shape, and derives its nerve-supply from the infraspinous branch of the suprascapular nerve. The supraspinatus muscle (I ig. 251) arises from the outer two-thirds of the fossa of the >ame name and also from the dense aponcurosis covering the muscle. It is inserted into the upper facet 'f the greater tuberosity of the humerus. It is covered (i) by a dense fascia of the same name ; (2) by the trape/.ius muscle, which is inserted into the upper lip of the scapular spine. (Fig. 250.) Kxpose this supraspinatus muscle by cutting the insertion of the trape/ius. Then you may trace the supraspinatus under the acromion process to its inser- SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 359 tion. Cut this muscle at its insertion, turn it back (Fig. 254), and find the vessels and nerves the suprascapular that supply this region. The suprascapular artery and nerve will come into view as you turn aside the supraspinatus muscle. (Figs. 249254.) The nerve you will trace through the suprascapular foramen under the transverse ligament. (Fig. 252.) The artery crosses the transverse ligament. (Fig. 252.) Each structure divides into supra- spinous and infraspinous branches. Trace these vessels and nerves out to their respective localities of distribution. (Fig. 254.) The anastomosis between the suprascapular artery and the dorsal branch of the subscapular takes place in the infraspinous fossa, on the bone. Find this. (Fig. 249.) Anastomosis about the shoulder includes the following arteries, which you may now demonstrate. (Fig. 254) : Circumflex, subscapular, dorsalis Transverse ligament Conoid ligament Acromio-clavicular ligament Tendon of infra- spinatus and tares minor Inferior transverse or spino-glenoid ligament Capsule of shoulder FIG. 252. POSTERIOR VIEW OF THE SHOULDER-JOINT, SHOWING ALSO THE ACROMIO- CLAVICULAR JOINT AND THE PROPER LIGAMENTS OK THE SCAPULA. scapulae, suprascapular, posterior scapular artery, a continuation of the trans- versalis colli, a branch of the thyroid axis of the subclavian. The triceps muscle (Fig. 253) has three heads. The longer scapular head you will now very carefully trace to the axillary border of the scapula, immediately below the glenoid fossa. As you have already observed, this head assists in forming boundaries for the quadrangular space and also for the two triangular spaces. The whole posterior surface of the humerus is occupied by the inner and outer heads of the triceps muscle, and the musculo-spiral groove. Dissection. Locate the musculo-spiral nerve and the superior profuncla artery in the second triangle. (Fig. 249.) Now the nerve will pass between the bone and muscle. Cut the muscle in a line corresponding to the course of the nerve, until you come to a point two inches above the outer condyle. The mus- cular mass attached to the posterior surface of the humerus above the groove, in 3 6 PR A CTICAL ANA TOM 3 . which you now see the musculo-spiral nerve, is called the external, or long humeral head of the triceps ; the mass below the musculo-spiral groove is called the internal or short humeral head. Trace the triceps muscle to its insertion, into the olecranon process of the ulna. Cut the insertion of the triceps and study the capsule of the elbow-joint and the olecranon fossa. FIG. 253. TRICEPS BRACHIALIS, POSTERIOR A.SI>KCT. I. Long, middle, or scapular head. 2. Its tendon of origin from scapula. 3. External, or long humeral head. 4. Internal, or short humeral head. 5. Common tendon. 6. Attachment to olecranon. 7. Anconeus. 8, 8. Upper portion of deltoid, posterior half removed. 9. Lower portion. 10. Supraspinatus. II. Infraspinatus. 12. Teres minor, middle portion removed. 13. Insertion of teres minor into humerus. 14. Teres major. 15. Upper extremity of latissimus dorsi. 16. Supi- nator longus. 17. Extensor carpi radialis longior. 18. Extensor carpi ulnaris. 19. Flexor ca: ulnaris. * Nei~i>e-supply to the Triceps. As you dissect between the two humeral heads of the triceps, notice the large number of branches given off to the muscle from the musculo-spiral nerve, a branch of the posterior cord of the brachial plexus. 1. J /<>:,' many origins /ins tin deltoid muscle / Two ; one from the lower lip of the scapular spine and acromion, another from the outer one-third of the clavicle. (Fig. 252.) 2. Tlie origin of (lie deltoid, tlicn, may be said to correspond to tlie insertion oj muscle f To the insertion of the trape/itis, since this muscle is inserted into the uppei SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 361 lip of the scapular spine and acromion, and into the posterior outer one-third of the clavicle. (Fig. 252.) 3. Describe the circumflex nerrc. It is a branch of the posterior cord of the brachial plexus. (Fig. 42.) It passes through the circumflex quadrangular space, to the back of the shoulder. It gives muscular branches to the deltoid and teres minor muscles, and cutaneous branches to the skin covering the insertion of these muscles and articular branches to the shoulder-joint. (Hilton's la\v.) Supra-spinatua Suprasca/mlar artery Posterior scapular artery | | Infra-spinatus Hhomboideus minor / Levator anguli scapulae Triceps, cut Deltoid, insertion Deltoid Trapezius Rhomboideus major Terea major muscles Deltoid muscle / Triceps Teres major, insertion Dorsalis scapulae artery Posterior circumflex artery FIG. 254. THE DORSAL SCAPULAR ARTERY. (From a dissection in the Museum of the Royal College of Surgeons.) 4. Describe the suprascapular nerve. A branch of the upper trunk of the brachial plexus. (Fig. 42.) It passes through the constant suprascapular foramen. It gives muscular branches to (i) the supraspinatus, (2) the infraspinatus, and articular branches from each muscular branch, to the shoulder-joint. (Hilton's law.) 5. Describe the muscnlo-spiral nerve. It is a branch of the posterior cord of the brachial plexus. (Fig. 42.) It may be found on the floor of the second triangular space. (Fig. 249.) It passes between the two humeral heads of the triceps in the musculo-spiral groove of the humerus. It lies between the brachialis anticus and brachio-radialis muscles in the lower third of the arm. It gives muscular branches to the triceps and anconeus 24 362 PRACTICAL ANATOMY. and to all the muscles in the radial region, and also to all the muscles on the pos- terior part of the foramen. Its cutaneous branches are as follows : (i) Radial, to the integument of the ball of the thumb and to three and one-half ringers dorsally, as far as the base of the distal phalanx (Fig. 242) ; (2) internal cutaneous branches to the skin on the inner and posterior part of the arm ; (3) external cutaneous branches to the skin on the outer and front part of the arm. (Fig. 241.) The articular branch to the shoulder is sometimes taken with the circumflex. The posterior nerve-cord is composed of both the circumflex and musculo-spiral and other branches. 6. Name tJic muscles arising from the external condylar ridge. The brachio-radialis and extensor carpi radialis longior. 7. Give the origin, course, and distribution of the posterior interosseons nerve. A branch of the musculo-spiral ; it passes between the upper and deep layers of the supinator brevis muscle. It lies between the deep and superficial groups of posterior forearm muscles, which it supplies. Note that the musculo-spiral nerve gives off branches to the radial group of muscles prior to its division into the radial and posterior interosseous. Demonstrate this on your dissection. If you have not already done so, review you dissection of the musculo- spiral nerve and show that the branches that supply the humeral heads of the triceps muscle are given off at the back of the humerus ; that branches are given off in the axilla to the scapular head. This nerve sometimes accompanies the ulnar nerve as a long slim branch, known as the ulnar collateral. 8. Describe tlie dorsal inter ossei muscles. They are four in number. They are supplied by the ulnar nerve. They have origin from the contiguous sides of the metacarpal bones. (Fig. 248.) Their single independent action is abduction of the fingers, which is always associated physiologically with supination of the radius. Their synergistic action is with the palmar interossei and lumbricales to produce metacarpo-phalangeal flexion, and extension of the second and third phalanges. They are inserted into the bases of three fingers, as shown in figure 248. 1. Describe tJie median nerve. It arises by two heads an outer and an inner from the outer and inner cords of the brachial plexus respectively. (Fig. 42.) It accompanies the axillary artery and its prolongation, the brachial, to the elbow. It gets into the forearm by passing between the condylar and coronoid heads of the pronator radii tores muscle. It gives off no branches to the flexor muscles of the forearm. It is, in rare cases, fused with the musculo-cutaneous nerve. It is said to give off two articular branches to the elbow-joint. It supplies all the muscles on the anterior surface of the forearm, except the flexor carpi ulnaris, and one-half of the flexor profundus digitorum. It supplies three and one-half fingers with sensation. In the hand it supplies the two radial lumbricales and all the muscles of the thenar eminence, except the adductor pollicis and one head of the flexor brevis pollicis. It is accompanied by an artery below the elbow. Sometimes this artery is as large as the radial. It passes under the anterior annular ligament. In the forearm the median nerve lies in the sheath of the flexor sublimis digitorum, on the posterior surface of this muscle. The digital branches of this nerve supply the finger-joints. 2. Describe tlic itlnar nerrc. It is a branch of the inner cord of the brachial plexus. It is attended by the inferior profunda artery above the elbow, and by the ulnar below. It gains the forearm by passing between the two heads olecranon and condylar of the flexor carpi ulnaris. It supplies the flexor carpi ulnaris, and the ulnar half of the flexor profundus digitorum. It supplies one and one-half fingers dorsally and paltnarly. It supplies in the hand all the muscles not innervated by the SHOULDER, ARM, FOREARM, HAND. POSTERIOR PART. 363 median nerve. It gives articular branches to the elbow and wrist, and all subse- quent joints moved by the muscles which it supplies. Demonstrate the dorsal ulnar cutaneous nerve. (Fig. 242.) 3 . Describe the musculo-spiral nerve. It is a branch of the posterior cord of the brachial plexus. (Fig. 42.) It is found between the two humeral heads of the triceps muscle in the musculo-spiral groove with the superior profunda artery. In the lower one-third of the arm it lies between the brachialis anticus and supinator longus. In this place it gives off branches to the radial group of muscles the supinator radii longus, the exten- sor carpi radialis longior and brevior. It divides then into the radial and poste- rior interosseous. The posterior interosseous passes through the supinator b re vis and then supplies the muscles on the posterior part of the forearm. The radial branch becomes cutaneous by piercing the deep fascia in the lower one- third of the forearm, between the supinator longus and the extensor carpi radialis. In the hand the nerve supplies the ball of the thumb and adjacent three and one-half fingers dorsally. (Fig. 242.) The musculo-spiral nerve gives off two cutaneous branches to the skin over the insertion of the triceps and anconeus. 4. Describe the musculo-cutaneous nerve. This is a branch of the outer cord of the brachial plexus. (Fig. 42.) It per- forates, as a rule, the coraco-brachial muscle, and gains the intermuscular space between the biceps and brachialis anticus. It supplies the coraco-brachial and the flexor muscles of the forearm, the biceps, brachialis anticus, and supinator longus ; the cutaneous part is distributed to the skin over the insertion of these muscles. 5. Describe the circumflex nerve. It is a branch of the posterior cord of the brachial plexus. (Fig. 42.) It passes through the quadrangular space to the back of the shoulder with the posterior circumflex artery. (Fig. 249.) It supplies the deltoid and teres minor muscles. It gives two articular branches to the shoulder-joint and cutaneous branches to the skin over the insertion of the deltoid and teres minor muscles. 6. Name the important regions of geometrical parts in the upper extremity. (i) The radial groove ; (2) the ulnar groove ; (3) the cubital fossa; (4) the brachial groove ; (5) the axilla ; (6) the quadrangular space (7) the first tri- angular space ; (8) the second triangular space. 7. Give t/ic special names for deep fascia in the tipper extremity. (i) Anterior annular ligament; (2) posterior annular ligament ; (3) dorsal fascia ; (4) palmar fascia ; (5) ligamenta vaginales ; (6) bicipital fascia ; (7) axillary fascia; (8) clavi-pectoral fascia; (9) costo-coracoid ligament; (10) pectoral apo- neurosis ; (11) deltoid aponeurosis ; (12) supraspinous fascia ; (13) infraspinous fascia ; (14) superior transverse scapular ligament ; (i 5) inferior transverse scapu- lar ligament. (Fig. 252.) 8. What structures did you find under the anterior annular ligament at the carpus ? (i) The flexor sublimis digitorum ; (2) the flexor profundus digitorum ; (3) the flexor longus pollicis ; (4) the median nerve and its artery. 9. Give boundaries of the radial groove, and its contents. On the radial side is the supinator longus muscle ; on the ulnar side, in the upper third, the pronator radii teres ; in the remainder of its course, the flexor carpi radialis. In front of the artery the skin and fasciae form the roof of the radial groove. Behind the artery, from above, are : (i) The biceps ; (2) supinator brevis ; (3) pronator radii teres ; (4) flexor sublimis digitorum ; (5) flexor longus pollicis ; (6) pronator quadratus ; (7) a small part of the lower end of the radius. The radial groove contains the radial artery and its vena; comites. 10. Give boundaries and contents of the ulnar groove. The ulnar groove contains the ulnar artery and its venae comites. The artery 3 6 4 PRACTICAL ANATOMY. is a branch of the brachial artery, being given off from this vessel in the cubital fossa. The groove is limited on the ulnar side by the flexor carpi ulnaris, this muscle being the guide to the artery in the lower two-thirds of its forearm course ; on the radial side by the flexor sublimis digitorum ; behind by the brachiali.s anticus, the flexor profundus digitorum, and the pronator quadratus. The ulnar artery is covered in the lower two-thirds by the skin and fasciae. In its course from the cubital fossa to the ulnar groove proper, the artery passes behind all the muscles that originate from the inner condyle of the hurherus, except the flexor carpi ulnaris. On entering the groove proper the artery is joined by the ulnar nerve. 1 1. Give boundaries of the cubital fossa, and tell what you found in this fossa. Externally, is the supinator longus muscle ; internally, the pronator radii teres ; above, an imaginary line passing through the humeral condyles. The roof is formed by the skin and fasciae. The floor is formed by the brachialis anticus and supinator brevis, containing between its superficial layers the posterior inter- osseous nerve. The fossa contains the tendon of the biceps and bicipital tuber - osity ; the median nerve ; the brachial artery, dividing into the radial and ulnar arteries ; the musculo-spiral nerve, dividing into the radial and posterior inter- osseous nerves ; the cutaneous branch of the musculo-cutaneous nerve ; the median cephalic and median basilic veins. The student should now review the scheme of the brachial plexus on page 77, et seq. POSTERIOR PART OF LOWER EXTREMITY. Dissection. Locate greater trochanter, sacrum, coccyx, tuber of ischium, crest of. ilium, inner and' outer hamstrings, head of fibula, neck of fibula, os calcis, inner and outer malleoli. Incisions. (i) From centre of crest of ilium to centre of the os calcis ; (2) from greater trochanter to coccyx ; (3) from internal to external condyle ; (4) from inner malleolus to outer malleolus. Cut deeply enough to permit the edges of the skin to separate one-half of an inch with ease. In removing the skin from any area, cut closely enough that light may shine through the skin. The thing you see now having removed the skin is the superficial fascia. It contains the following structures in a variable amount of fat (Fig. 255) : Cutaneous or sensory nerves in figure 255. 1 . TIic twelfth or last thoracic nerve below the twelfth rib. 2 . The iliac brancJi of the ilio-liypogastric nerve. 3 . Posterior branches of the lumbar and sacral nerves. 4. The external cutaneous nerve of the lumbar plexus. 5. Tlie small sciatic of the sacral plexus. 6. The cutaneous branch of the obturator nerve. 7. Twigs from the long or internal saphenous. 8. The short saphenous, formed, as you see in figure 255, by the communicans tibialis and communicans fibularis, branches of internal and external popliteal respectively. 9. The short saphenous vein, with the nerve described in the preceding para- graph. This vein comes from the outer end of the dorsal arch of the foot, runs behind the outer malleolus of the fibula, passes up the mid-line of the leg, between the two heads of the gastrocnemius muscle, pierces the deep popliteal fascia, and opens into the popliteal vein. Describe the twelfth thoracic nerve. It is seen giving (i) a cutaneous branch to the anterior part of the gluteal region ; (2) a cutaneous branch to the anterior part of the abdominal walls as low as the hypogastric region. The nerve lies below the last rib, with the first lumbar artery. It crosses the quadratus lumborum muscle, and its muscular branches are distributed like the other abdominal intercostals. Describe the ilio- hypogastric nerve. This is a branch of the lumbar plexus, being given off from the first lumbar with the ilio-inguinal nerve. The iliac branch supplies the integument of the front part of the gluteal region. The hypogastric branch pierces the aponeurosis of the external oblique muscle one inch above the external abdominal ring, and supplies the skin in this region. Observe that the posterior branches of the lumbar and sacral nerves supply the skin over the glutens maximus muscle. Remember, the external cutaneous branch of the lumbar plexus supplies the skin covering the vastus externus, and may be considered a dismembered branch of the anterior crural nerve, according to Hilton's law. 365 366 PRACTICAL ANATOMY. The small sciatic nerve supplies the skin covering the flexor muscles of the leg. It may be regarded as the dismembered branch of the great sciatic nerve. The long pudendal branch of this nerve crosses the tuber ischii and is distributed to the scrotum of the male and its homologue, the labia majora of the female. The long saphenons nerve is a branch of the anterior crural, but to carry out the law governing cutaneous distribution, it extends to the inner side of the ankle, to supply the skin over the fullest insertion (periosteal) of the sartorius. If you will now clean off all the fat, you will see a rather dense fascia cover- ing the muscles. This is the deep fascia. That part of this fascia that covers the popliteal space is called the popliteal fascia. Now remove the deep fascia and make your muscles look like figure 256, taking pains not to destroy vessels and nerves. You have now exposed to view the gluteus mediu's and maximus, biceps, semitendinosus, semi-membranosus, gracilis, sartorius, plantaris, gastrocnemius, and tendo Achillis. THE POPLITEAL SPACE is a surgical area occupying the lower posterior one-third of the thigh and the upper posterior one-sixth of the tibia. It is diamond in shape. Its floor is formed by the femur, ligament of Winslow, and popliteus muscle. Its roof is formed by the skin, superficial fascia, and deep popliteal fascia. (See above.) The space is bounded (Fig. 256), above the joint, externally by the biceps muscle, internally by the semitendinosus, semi-membranosus, gracilis, and sartorius ; below the joint, externally by the outer head of the gastrocnemius and plantaris muscle, internally by the inner head of the gastrocnemius. The space contains, in a variable amount of fat and connective tissue : 1. The terminus of the short saphenous vein in the popliteal. 2. The descending branch of the small sciatic nerve. (Fig. 260.) 3. The communicating branches to the short saphenous nerve. 4. The internal popliteal nerve in the centre of the popliteal space. (Fig. 266.) 5. The external popliteal nerve with the biceps tendon. 6. The articular branch of the obturator nerve to the knee. 7. The popliteal artery and vein and their branches. In figure 255 note in particular the formation of the short or external saphenous nerve, by the union of two communicating branches, from the inter- nal and external popliteal nerves. There is no constant level at which this union takes place between the communicans tibialis and the communicans fibularis. Locate tlie popliteal space. It occupies the lower posterior one-third of the thigh and the upper poste- rior one-sixth of the leg ; it extends from the aperture in the adductor magnuj muscle to the lower border of the popliteus muscle. dire tlic relation, in tlic centre' of tlie space, of the internal popliteal ncri-c, and tlie popliteal vein an is as follows : having cut through the skin, super- ficial fascia, and deep fascia, called in this region popliteal fascia, the most super- ficial structure seen in the space under the deep fascia is the internal popliteal nerve; the next deep structure immediately under the nerve is the popliteal vein ; the third deep structure is the popliteal artery. This relation of the vein to its artery is in harmony with the rule governing the relation of arteries their veins, above and below the diaphragm. POSTERIOR PART OF LOWER EXTREMITY. 3 6 7 Why this relation of artery and vein ? The rule is : Veins are behind their arteries below the diaphragm, and in front of them above the diaphragm where they are not on the same plane. Exception to rule : the renal vessels. What can yon say about the internal popliteal nerve ? (Fig. 266.) It begins at the bifurcation of the great sciatic, and ends at the lower border of the popliteal space, where its continuation through the leg is called posterior tibial. In its course it throws off these branches : i. The communicans tibialis or communicans poplitei. LAST THORACIC ILIO-HYPO- GASTRIC EXTERNAL CUTANEOUS EXTERNAL CUTANEOUS COMMUNI- CANS FIBULARIS SHORT SA PHENOL'S POSTERIOR BRANCHES OF LUMBAR NERVES POSTERIOR BRANCHES OF SACRAL NER VES PERFORATING CUTANSOU8OF SECOND AND THIRD SACRAL LONS PUDENDAL BRANCHES OF SMALL SCIATIC OBTURATOR POSTERIOR BRANCH OF INTERNAL CUTANEOUS CO.VMUNI- CANS TIBIALIS TWIGS FROM LONG S A PHENOL'S INTERNAL CALCANEAN FIG. 255. DISTRIBUTION OF CUTANEOUS NERVES ON THE POSTERIOR ASPECT OF THE INFERIOR EXTREMITY. 2. Three articular branches to the knee-joint. 3. Muscular branches to the gastrocnemius, soleus, plantaris, popliteus. The articular branches reach the knee-joint how ? One goes with the azygos artery, and two accompany the internal articular arteries, superior and inferior. Describe the external popliteal nerve. It begins at the bifurcation of the great sciatic, is found in the outer side of the popliteal space in the sheath of the biceps muscle. It leaves the space between the biceps and the outer head of the gastrocnemius muscle. It crosses the neck of the fibula, having passed behind the head of this bone, and terminates in the anterior tibial and musculo-cutaneous nerves. In its course it gives off these 3 68 PR A CTJCAL ANA TOMY. Oluteus medius Aponeuroeis of eluteus maxjmus Vaatua externus Gluteua maximus Peroneua longui Semi-membranoaus Semi-tendinosus Gracilis Tendon of semi-membranosas Sartoiiua Flexor longus difcitorum Tendo Achillii KM:. 256. Sri'KKi i. IAI MK.M i K> 01 mi. i:.\< K (i nn '1'iiu.ii AND LEG. POSTERIOR PART OF LOWER EXTREMITY. 369 \ branches : (i) The communicans fibularis or communicans peronei ; (2) three articular branches to the knee. (Fig. 264.) 77*6' articular branches reach the joint how ? One goes with the anterior tibial recurrent artery. Two accompany the external articular arteries, superior and inferior. Remember, nerve trunks that supply muscles, supply the skin covering the muscles, and the joints the muscles move. Describe the popliteal artery. It extends from the aperture in the adductor magnus muscle, to the lower border of the popliteus muscle. It is a continuation of the superficial femoral artery. In its course it gives off these branches : (i) Muscular to the borders of the popliteal space ; (2) articular branches, five in number, called superior two (internal and external), inferior two (internal and external), and one called the azygos. These arteries, as above indicated, are all accompanied by articular nerves from the popliteal branches of the great sciatic nerve. Short saphenons nerve is iiow formed, and where distributed / It is formed by the union of the communicans tibialis and communicans fibularis branches of the internal and external popliteal nerves respectively, and distributed to the posterior part of the leg and to the outer border of the foot. /// how many zvays is the scmimcmbranosns muscle inserted? In two ways : (i) Tendinously, into the inner tuberosity of the tibia ; (2) apo- neurotically, in (a) ligament of Winslow, (<$) into internal lateral ligament of the knee, (r) into the oblique line of the tibia, as the popliteal aponeurosis. Notice, aponeuroses are named according to the name of the muscle they cover or the surgical area they invest e. g., axillary, masseter, parotid, etc. Explain tlie insertion of the gracilis, semitendinosus, and sartorius. They are inserted into the upper one-third of the inner surface of the tibia, below the tuberosity ; the gracilis and semitendinosus by tendon, the former one- half inch the higher. The sartorius is inserted by a broad aponeurosis, which completely covers in the insertions of the other two muscles. The ] icads of the gastrocnemius differ in origin how / The inner head arises above the condyle ; the outer, from the side of the condyle. The latter seems to have been crowded out of place by the plantaris muscle at least let this suggestion aid the memory. Geometrical Inventory of the Popliteal Space : Roof skin, superficial and deep fasciae. Floor femur, ligament of Winslow, popliteus muscle. Superior end aperture in the adductor magnus muscle. Inferior end oblique line of the posterior surface of the tibia. Superior border externally, the biceps muscle. Superior border internally, semitendinosus, semimembranosus, gracilis, and sartorius muscles. Inferior border internally, inner head of the gastrocnemius. Inferior border externally, outer head of the gastrocnemius and plantaris. Shape diamond ; resembling two triangles with bases together. In the center are seen the internal popliteal nerve and popliteal vessels. Outer border the external popliteal nerve is in the sheath of biceps. 370 PRACTICAL ANATOMY. THE GLUTEAL REGION. The gluteus maximus muscle (Eig. 256) must now be put on the stretch by rotating the entire limb inward, and at the same time drawing the subject to the edge of the table and slightly lowering the leg. Now, with a sharp scalpel remove the deep fascia from the muscle itself (Fig. 257), and locate the line of differentiation between the gluteus maximus and medius. Theoretically, this is easily done, but practically some experience is necessary to obtain perfect results, since the gluteal aponeurosis continues forward and completely covers the gluteus medius muscle. The gluteus maximus originates : (i) From the aponeurosis of the gluteus medius ; (2) from the lumbar aponeurosis and the greater sacro-sciatic ligament ; (3) from the side of the coccyx ; (4) from the back of the lateral part FIG. 257. GLUTEUS MAXIMUS MUSCI.K. I. Gluteus maximus. 2. Its inferior portion. 3. Fibres of attachment to linea aspera. 4. Superior portion. 5, 5. Tendinous fibres of insertion into linea aspera. 6. Upper portion of femoral apo- neurosis. 7. Duplicature of this aponeurosis at superior level of gluteus maximus. 8. Portion of its superficial layer attached to tendinous bands. 9. Lower extremity of tensor vaginae femoris. 10, IO. Portion of femoral aponeurosis continuous with tendinous fibres of gluteus maximus. 11. Upper portion of biceps femoris. 12. Upper portion of semitendinosus. 13. Upper portion of seminiembranosus. 14. Gracilis. of the lower two segments of the sacrum ; (5) from the posterior one-fifth of the outer lip of the iliac crest ; (6) from the surface of the bone between the crest of the ilium and the superior gluteal ridge. ( l ; ig. 226.) The muscle is inserted into: (i) The ilio-tibial band; (2) into the gluteal ridge of the femur. (Fig. 227.) The inferior gluteal nerve, a branch of the sacral plexus, supplies this muscle. Cut at its insertion into the deep fascia of the thigh, and into the gluteal ridge of the femur, the gluteus maximus ; turn tin- same back, as seen in figure 258. Also cut the insertion of the gluteus medius at the oblique line of the greater trorhanter (Fig. 227), turn same up. and develop your work like figures 258 and 259. Caution! Take the greatest care, in turning the POSTERIOR PART OF LOWER EXTREMITY. 371 above muscles back, not to injure the vessels and nerves, upon which both the beauty and benefit of your dissection depend. You have exposed to view now these structures : 1. The greater sacro-sciatic foramen. (Fig. 226.) 2. The lesser sacro-sciatic foramen. (Fig. 226.) 3. Sacro-sciatic ligaments greater and lesser. (Fig. 258.) 4. The three gluteal muscles. 5. The pyriformis muscle. 6. The obturator externus muscle. 7. The obturator intern us muscle. 8. The gemelli superior and inferior. 9. The quadratus femoris muscle. 10. The superior gluteal nerve and artery. 1 1. The small sciatic nerve and its branches. Sciatic artery INFERIOR GLUTEAL NERVE Gluteal artery Gluteus medius Gluteus maximus BRANCH TO GLl'- TEUS MAXIMUS Tendon of obturator externu3 Vastus externus Gluteus maximus FIG. 258. A DISSECTION OF THE NERVES IN THE GLUTEAL REGION. (The gluteus maximus and glutens medius have been divided near their insertions, and thrown upward.) 12. The sciatic artery and its branches. 13. The great sciatic nerve and its relations. 14. The internal pudic nerve and artery. 15. The origin of the biceps, semitendinosus, and semimembranosus. 1 6. The gluteus medius muscle. 17. The gluteus minimus muscle. 1 8. The subgluteal bursa over the greater trochanter. The gluteus medius arises from the outer lip of the iliac crest for the anterior four-fifths ; from the outer surface of the ilium, between the superior and middle gluteal curved lines (Fig. 226) ; from the dense aponeurosis covering the muscle and separating the same from the gluteus maximus. The muscle is inserted into the oblique line of the greater trochanter of the femur. (Fig. 227.) Nerve-supply is the superior gluteal from the lumbo-sacral cord of the sacral plexus. (Fig. 193.) The gluteus minimus arises from the outer surface of the ilium, between the 372 PRACTICAL ANATOMY. middle and the inferior curved gluteal lines (Fig. 226), from the capsule of the hip, and is inserted into the anterior border of the greater trochanter. (Fig. 228.) The nerve-supply is from the superior gluteal. (See page 28 1 , Superior Gluteal Nerve.) Notice the common origin of the long head of the biceps and semitendin- osus from the tuber of the ischium. (Fig. 226.) See where the semimem- branosus, in its origin from the tuber, crosses the two preceding muscles since it arises from the upper and outer part of the tuberosity. Greater Sacro-sciatic Foramen. The notch of the same name (Fig. 226) is converted into this foramen by the lesser sacro-sciatic ligament. It transmits the pyriformis muscle, which divides the foramen into an upper and a lower com- partment. (Fig. 258.) Above the muscle emerge the superior gluteal artery and nerve ; below the muscle, the greater sciatic nerve, the lesser sciatic nerve, the sciatic artery, the internal pudie ncn'c and artery, and the inferior gluteal nerve. The pyriformis muscle arises from the anterior surface of the sacrum, be- tween the four upper anterior sacral foramina. The muscle leaves the pelvis by the greater sacro-sciatic foramen, and is inserted into the upper border of the greater trochanter. The Gluteal Artery (Fig. 258). The largest branch of the internal iliac; leaves the pelvis by the greater sacro-sciatic foramen, above the pyriformis, divides into a superficial and a deep branch. The former lies between the glutens maximus and medius, and anastomoses with the circumflex iliac branch of the external iliac artery ; the latter the deep branch lies between the gluteus medius and minimus, and anastomoses with the external circumflex artery, a branch of the prof un da. The superior gluteal nerve a branch of the lumbo-sacral cord of the sacral plexus accompanies the artery of like name (Fig. 258) and supplies the gluteus medius and minimus and the tensor vaginae femoris. The Sciatic Artery (Fig. 258). A branch of the internal iliac. It leaves the pelvis below the pyriformis muscle. It gives branches to the rectum, base of bladder, seminal vesicles, prostate, and all the muscles of the pelvic floor. It sends branches to the muscles on the back of the hip ; one branch, the comes neri'i iscJdadici, to the great sciatic nerve. (Fig. 258.) It anastomoses with the gluteal, the obturator, both circumflex arteries, internal and external, and with the superior perforating artery, a branch of the profunda femoris. The Great Sciatic Nerve (Fig. 193). The largest branch of the sacral plexus. Leaves the pelvis below the pyriformis. Lies upon successively the superior gemellus, the internal obturator, the inferior gemellus, the external obturator, the quadratus femoris, and the adductor magnus. (Fig. 258.) It ends in the popliteal space, in the internal and external popliteal nerves. It gives motor branches to the biceps, semitendinosus, semimembranosus, and adductor magnus muscles. It gives to the hip-joint articular branches, which perforate the posterior part of the capsule. The Small Sciatic Nerve (Fig. 260). A branch of the sacral plexus. ( Fig. 193.) It leaves the pelvis below the pyriformis muscle, lying behind the greater sciatic nerve. Its branches are cutaneous : ascending, internal, external and descending. The latter passes through the popliteal space to supply the skin over the insertion of the flexors of the leg. (Fig. 255.) The small sciatic is then the great divoircd sensory branch of the great sciatic, carrying out Hilton's law. The internal branches of this nerve are numerous. (Fig. 260.) The short ones supply the skin on the inner side of the thigh ; the longest one of the internal branches is called the inferior pudenda!, or nerve of Sdemmering, and supplies tin- scrotum and labia majora. How to find the long pudendal in practical anatomy : It crosses the tendons of the biceps and semitendinosus, on the tuber of the ischium. (Fig. 260.) POSTERIOR PART OF LOWER EXTREMITY. 373 The Inferior Gluteal Nerve. A branch of the sacral plexus. Leaves the pelvis by the greater sacro-sciatic foramen, below the pyriformis, and supplies the gluteus maximus. (Fig. 258.) The Lesser Sacro-sciatic Foramen. The notch of the same name is con- Gluteus medius Pyriformis Gemellus superior Gemellus inferior Quadratus femoris Gluteua maximus Vastus externus Biceps Crureus Short head of biceps Plantaris Oastroonemiue Obturator interims Adductor magnuS FIG. 259. THE EXTERNAL ROTATORS AND THE HAMSTRING MUSCLES. verted into this foramen by the greater sacro-sciatic ligament. (Fig. 259.) It trans- mits the internal obturator tendon and its nerve, the internal pudic nerve, artery, and vein. (Fig. 258.) The vessels and nerve lie above the tendon. To trace these structures properly, it will be necessary to remove the gluteus maximus from the 374 PRACTICAL ANATOMY. greater sacro-sciatic ligament, and then cut the latter. You \vill then see the internal pudics all entering Alcock's canal. (Fig. 258.) Branches and Course of Internal Pudic Nerve. A branch of the sacral plexus. (Fig. 194.) The nerve escapes from the pelvis by the greater sacro- sciatic foramen, crosses the spine of the ischium, enters the pelvis by the lesser sacro-sciatic foramen (Fig. 226), above the tendon of the obturator internus muscle, traverses a delamination of the obturator fascia, called Alcock's canal, in Gluteus uiedius Gluteus minimus Pyriformis, divided into two by the great sciatic nerve GREAT TROCHANTER Obturator ezternus Quadratus femoris Faacial insertion of gluteus mazimus Horizontal fibres of adductor inagnus Fleshy insertion of gluteus mazimus GREAT SACRO-SCIATIC FORAMEN GLUTEAL NERVE SUPPLYING POR- TIONS OF GLU- TEUS MEIHUS GHuteus mazimus Obturator interims. Below is the infe- rior gemellus. The superior gemellus is absent BRANCHES Of-' J\- FER10I! DAL NERVE GKEAT SCIATIC NEKVE. Under it, oblique fibres of adductor magnus are seeu SMA LL SCI A TIC NER VB FIG. 260. DEEP DISSECTION OK THI <;i.> n \\ Kuans. (From a preparation in the Hunterian Museum.) the outer wall of the ischio-rectal fossa. It gives off the following branches : (l) The inferior liu'inorrlioidal, which crosses the ischio-rectal fossa and supplies the skin around the anus ; (2) the perinea!, which supplies tin- integument of tlu- scrotum and tin- labia majora, the transversus perin;ei, the accelerator urina/, the erector penis, and the compressor urethne, or deep internal transversus perinaei muscle; (3) the dorsal nerre of the penis, which gives off branches to the skin of the penis, and to the corpus cavernosum. POSTERIOR PART OF LOWER EXTREMITY. 375 Greater Trochanter (Figs. 227 and 228). Muscles inserted into: (i) The glutens inedins into the oblique line. (2) The glutens minimus into the anterior surface. (3) The obturator externus into the digital fossa. (4) Into the superior border, in the following order, from before backward : the pyrifonnis, the gcuuihis superior, the obturator interims, and the gcmellus inferior. This is the logical order of insertion, since they leave the pelvis in this order. (5) Into the base you will see the vastus externus. (Fig. 228.) Now turn to figures 227 and 228 and study these insertions on the bone. In your dissection trace each tendon to its complete insertion. Gluteus Maximus Insertion. This muscle is inserted into the gluteal ridge of the femur. This is called the third trochanter when it is very large. It is one of the constituent parts of the linea aspera. Turn to figure 227, and study the linca aspera. (Read page 329 on linea aspera.) External Rotators of the Thigh. From the nature of the origin and in- sertion of the pyriformis, gemelli, obturators, and quadratus femoris, they will produce external rotation of the limb, when this is straight that is, when its long axis parallels the long axis of the trunk, as in* the standing or recumbent posture. In the sitting posture, however, when the limb is at right angles to the trunk, they make 'traction parallel to the long axis of the femur, and thereby PATELLA Synovial membrane Capsule - FEMUR Crucial ligaments ! Vt^iHBfitoffiiS! SSMP.W Inner head of gastroccemius Biceps ^liisSFQm^SF^r"' Sartorius Outer head of gastroonemius - :S ^ ; C!>^ 5&ffiP^!" quadratus fenu>ri>. 17. Tendon of obturator externus. 18. Attach- ment of glutens medius. 19. Obturator internus. 20. Tendon of pyramidalis. 21. (Unions mini- mus. 22. Divided inner ln-ad of gastrocnrmiiis. 23. Outer head. 24. Plantaris. 25. Popliteus. 26. Soleus. 27. Fibrous ring for artery, vein, and nerve. FIG. 263. LONG HEAD OF BICEPS AND SEMI- TENDINOSUS. I. Long head of biceps. 2. Common tendon of head of biceps and semitendinosus. 3. Inferior tendon of biceps. 4. Semitendinosus. 5. Its tendon. 6, 6. Its tendinous expansions, con- tinuous with aponeurosis of leg. 7. Semimem- branosus. 8. Its inferior tendon. 9. Gracilis. 10. Its tendon. II. Sartorius. 12. Vastus ex- ternus. 13. Femoral attachment of gluteus maxi- nuis. 14. Insertion of gluteus medius. 15. (ilnteus minimus. 16. Tendon of pyriformis. 17. Obturator internus. 18. Quadratus femori.-. 19. Inner head of gastrocnemius. 20. Outer Ix-ud of gastrornrmius. 21. Plantaris. 22. Popliteal apqneurosis. POSTERIOR PART OF LOWER EXTREMITY. 377 muscle above and below from the gemelli. (Fig. 259.) Cut the muscle near its insertion into the greater trochanter, and then trace it back into the pelvis through the lesser sacro-sciatic foramen. Notice the strong converging tendin- ous bands on the under surface of the muscle. Also see the origins of the gemelli from the ischial tuber and spine. (Fig. 226.) Reduced to its simplest terms, wliat is a rational pliysiological grouping of tlie muscles primarily concerned in the movements of t lie 1 tip-joint? (i) Flexors of the thigh on the abdomen ; (2) extensors of the thigh on the abdomen ; (3) adductors of the thigh on the pelvis ; (4) abductors of the thigh on the pelvis ; (5) internal rotators of the thigh ; (6) external rotators of the thigh. Xamc the flexor muscles of tlic tJiigh. The iliacus and psoas magnus, inserted into the lesser trochanter of the femur, are, as Morris points out, almost pure flexor muscles. When, however, they deviate from flexion, they are to some extent internal rotators, and not, as is sometimes suggested, external rotators. Nerve-supply, second and third lumbar nerves. Hoiv is tlie t/iig/i extended on the pelvis / By the action of the gluteus maximus, which is the direct antagonist of the psoas and iliacus. Nerve-supply, the inferior gluteal nerve. Name the abductors of tJie hip-joint. The tensor vaginae femoris, the gluteus medius, the gluteus minimus. Nerve-supply, superior gluteal. Name t/ie adductors of the t/iigh or hip-joint / The obturator externus, the adductor longus, the adductor brevis, the adduc- tor magnus, and the adductor gracilis. Nerve-supply, the obturator. How is tJie t/iig/t or /tip-joint rotated inward ? By the anterior segments of the members of the abductor group of muscles viz., the glutei minimus and medius and the tensor vaginae femoris ; and, in addition, according to Morris, by the ilio-psoas muscle. Nerve-supply, superior gluteal. Name the muscles that rotate the thigh outward. The pyriformis, the obturator internus, the two gemelli muscles, and the quadratus femoris. These muscles all derive their nerve-supply from the sacral plexus. The obturator externus, although strictly speaking an adductor muscle, becomes an external rotator when the patient is in the sitting posture. Now, on figure 263 study the relation of the quadratus femoris, obturator internus, and the gemelli to each other. On figure 262, on which the quadratus and gemelli are removed, study the relation of the obturators to each other. BACK PART OF THE LEG. Locate the fibrous arch connecting the heads of the gastrocnemius muscle. (Fig. 259.) Notice passing downward into the deep intermuscular space the popliteal artery and vein, in their proper relation to each other, and the internal popliteal nerve. (Fig. 264.) Carefully isolate these structures from each other and from the arch. Then lift the arch upward and cut down between the two heads of the gastrocnemius to the point where this muscle joins the soleus. Also notice between these two muscles the plantaris, with its very long tendon. (Fig. 264.) Now cut the gastrocnemius (Fig. 264), and trace each head across the joint to its exact origin on the femur. (Fig. 227.) Notice the difference in origin 25 378 PRACTICAL ANATOMY. on the two sides. Also trace the plantaris up to its origin and be sure you find its nerve, a branch of the internal popliteal. (Fig. 264.) Locate the fibrous arch of the soleus. (Fig. 264.) See passing under the same the popliteal artery, nerve, and vein, now called posterior tibial, as far clown as the ankle, having passed under the arch of the soleus. Pull the arch up and cut down between the two heads of the soleus. By cutting in the mid-line of these two muscles you preserve the nerve-supply intact, which nerves it is desired you trace out carefully. You will remember the gastrocnemius, plantaris, soleus, and popliteus are supplied by the internal popliteal nerve. (Fig. 264.) Now let your dissection verify the complete distribution of the internal popliteal nerve. Preserve every branch of this nerve. On each side of the fibrous arch of the soleus, on the tibia and fibula, you Adductor magnua Popliteal vein Popliteal artery INTERNAL POPLITEAL NERVE Vastus interims Superior internal articular artery Tendon of semi-membranosus Inner head of gastrocnemius Inferior internal articular arler. Popliteal vein Popliteui Tendon of plantaris Vastuu eiternus GRKA T SCTA TIC SERVE Short head of biceps EXTERNAL POPLITEAL SERVE Long head of biceps, out Outer head of gastrocnemius COMMVNICAN8 PEROXEI XI-:J:VE - Soleus Qastrocnemius External saphenous vein and nerve FIG. 264. DEEP VIEW OF THE POPLITEAL SPACE. (Hirschfeld and Leveille.) will see the inner and outer heads of this muscle. (Fig. 208.) Divide them carefully one-half of an inch from their origin, and turn the three muscles of the superficial group aside, and figure 266 will represent what you should have. You now have in view these structures : 1. The posterior tibial nerve and its branches. (Fig. 266.) 2. The posterior tibial vessels and their branches. (Fig. 266.) 3. The remaining origins of the plantaris, soleus, and gastrocnemius, and the popliteus muscle, as seen in figure 265. 4. The tibialis posticus, an extensor muscle of the tarsus. 5. The flexor longus digitorum muscle a flexor of the four outer toes. 6. Tin- flexor longus hallucis muscle a flexor of the great toe. ~. The thin, dee]) transverse fascia, or deep intei muscular fascia of the leg, which you will now see covering in all the structures below the popliteus muscle. POSTERIOR PART OF LOWER EXTREMITY. 379 If you examine this fascia, you will find it attached internally to the tibia, ex- ternally to the fibula, and above to the oblique line of the tibia. (Fig. 208.) Outer head of gastrocnemiue Inner head of gastrocuemius Biceps ' Tendon of semi-metnbrauosus PeroneuB longus 1 Flexor longus hallucis PopliteuB Tibialia postieus Plexor longus digitorum Peroneus brevis . Tibialis postieus . Tendo Aehillis FIG. 265. THE DEEP MUSCLES OF THE BACK OF THE LEG. It is quite thin, yet strong, and permits the posterior tibial vessels and nerves to be seen through it. The Posterior Tibial Nerve (Fig. 266). It begins at the lower border of 3 8o PRACTICAL ANATOMY. the popliteal muscle ; it is a continuation of the internal popliteal nerve down- ward. It ends under the internal annular ligament (Fig. 266) of the ankle, Superior external articular artery POPLITEAL NERVE- External lateral ligament Inferior external articular artery Popliteus Muscular branch to soleus Soleus Anterior tibial artery Peroneus longus . Peroneal artery . BRANCH OF POSTERIOR TIBIAL . NERVE TO FLEXOR LONGUS HALLUCIS Flexor lougus hallucis Superior internal articular Popliteal artery Posterior ligament of knee Azygos articular artery SEMI-MEMBRANOSUS Inferior internal articular artery Muscitlar branch Tibialis posticus POSTERIOR TIBIAL NERVE MUSCULAR BRANCH OF POS- TERIOR TIBIAL NERVE TO FLEXOR LONGUS D1GITORUM Flexor longus digitorum Posterior tibial artery Cutaneous branch of peroneal artery Peroneus breviu Continuation of peroneal artery OS CALCIS Tibialis posticus ( 'iiinmi/n imthifj branch Internal annular ligament Internal calcaneal artery FIG. 266. RELATIONS OK THE I'ori.n KAI. AKTIKY ro BONES AND Mi * US. (The Mriu-tiiiv.- M-I-II in tliis li^un- :uv loveu-.l liy ilu- n aii>\ i-rse fascia. Sec P.IL;C ,i7>-.) between the internal inallrohis and <>< calcis, h\- di\iding into the internal and external plantar nerves. (Fig. 272.) It accompanies the posterior tibia! v first to tin- inner and latrr to tlu- outer side of these vessels. POSTERIOR PART OF LOWER EXTREMITY. POPLITEAL NOTCH External fibre-cartilage Capsule Posterior crucial ligament STYLOID PROCESS Posterior tibio-ftbular ligament Tibialis posticus Flexor longus hallucis FLEXOR SURFACE OF FIBULA NUTRIENT FORAMEN FIBULA Peroneus brevis Posterior tibio-flbular ligament GROOVE FOR FLEXOR LONGUS HALLUCIS External lateral ligament (posterior fasciculus) External lateral ligament (middle fasciculus) Internal flbro-cartilage Capsule Semimembranosus Popliteus OBLIQUE LINE Soleus POSTERIOR SURFACE OF TIBIA Flexor lonsus digitorum GROOVE FOR TIBIALIS POSTICUS AND FLEXOR LONGUS DIGITORUM Internal lateral ligament Posterior ligament of ankle-joint FIG. 267. THE LEFT TIBIA AND FIISULA. (Posterior view.) 3 82 PRACTICAL ANATOMY. Branches of Posterior Tibial Nerve. (i) An articular branch to the ankle, given off just above the bifurcation of the nerve into the internal and external POSTERO-INFERIOR SURFACE OF THE CALCANEUM Abductor minimi digit! Abductor oasis metatarsi quiuti Accessorius (outer head) Plexor brevis hallucis Abductor oasis metatarsi quinti Flexor brevis minimi digit! Adductor hallucis Third plantar interosseous Second plantar interosseous First plantar interosseous Flexor brevis minimi digit! Abductor brevis minimi digiti Third plantar interosseous Second plantar luterosseoua First plantar interosseous Flexor brevis digitorum Flexor lougus digitorum Abductor hallucis Flexor brevis digitorum Accessorius < inner headi Tibialis posticus Tibialls anticus Peroneus loneus .ri^ii-i: Abductor hallueia J ~K Flexor brevis halluoi* (inner portion) Flexor brevis hallucis (outer portion) Adductor hallucis Transversus pedis Flexor longus hallucia FIG. 268. Tin. I.I.KT FOOT. (Plantar surface. ) (Study the insertion and location of tendons on this and compare your dissection therewith.) plantar nerves. (2) A plantar cutaneous nerve, to the heel and inner side of the sole of the foot. (Fig. 272.) (3) Muscular branches to the tibialis posticus, flexor longus hallucis, and flexor longus digitorum musoK-s. ( Fig. 266.) POSTERIOR PART OF LOWER EXTREMITY. 383 (Fig. Two terminal branches the internal and external plantar nerves. 272.) Branches of the Posterior Tibial Artery. (i) The peroneal artery to the outer side of the leg. (Fig. 266.) (2) A nutrient artery to the tibia, which you will find entering the foramen as far down as the lower end of the oblique line of the tibia, on the ridge separating the origin of the tibialis posticus from the flexor longus digitorum. ( Fig. 208.) Find this artery and recall the rule for the direc- tion of these foramina in the long bones of the extremities : from the knee and FIG. 269. MUSCLES OF THE LEG, EXTERNAL ASPECT. Tibialis anticus. 2, 2. Tendon of extensor proprius pollicis. 3, 3. Extensor longus digitorum. 4. Its tendons for four last toes. 5. Peroneus tertius. 6. Its attachment to last two metacarpal bones. 7. Peroneus longus. 8. Its tendon. 9. Peroneus brevis. 10. Its tendon. II. Outer head of gas- trocnemius. 12, 12. Solens. 13. Tendo Achillis. 14. Extensor brevis digitorum. 15, 15. Ab- ductor minimi digiti. 16. Rectus femoris. 17. Vastus externus. 18. Its inferior fibres. 19. Tendon of biceps femoris. 20. External lateral ligament of knee. 21. Tendon of popliteus. toward the elbow. (3) A communicating branch to the peroneal, on the back of the tibia, under the flexor longus hallucis, two inches above the joint. (4) In- ternal calcanean, which communicates with the external calcanean branch of the peroneal artery behind the tendo Achillis. (Fig. 266.) (5) Muscular branches, small and numerous, to the soleus and deep muscles on the back of the leg. (Fig. 266.) The Posterior Tibial Canal. For practical purposes we may locate the posterior tibial nerve and its accompanying vessels in a canal, bounded as follows : 384 PRACTICAL ANATOMY. Externally, by the flexor longns hallucis ; internally, by the flexor longus digi- torum ; its floor is the tibialis posticus, flexor longus digitorum, tibia, and internal lateral ligament ; its roof, the deep transverse fascia, described in a previous paragraph. Deep Muscles of the Leg. (i) Popliteus ; (2) flexor longus hallucis ; (3) flexor longus digitorum ; (4) tibialis posticus. It is necessary now to study the posterior surfaces of the tibia. (Fig. 208.) Notice that the oblique line of the tibia has three lips : (i) An upper one, occupied by the insertion of the pop- liteus muscle ; (2) a middle one, by the soleus ; (3) a lower one, by two muscles the flexor longus digitorum on the outer side of the vertical line, and the tibialis posticus on the inner side. Notice, too, that the posterior surface of the fibula (Fig. 208) is occupied by the origin of two muscles : the outer head of the soleus, the upper one-third, and the flexor longus hallucis, the middle one-third, of this posterior surface. What can be said regarding t/ic rather peculiar origin and insertion of the flexor longus digitorum and flexor longus Jiallucis f They arise from surfaces of bone above, opposite their insertions, into the phalanges below : The great toe is on the side opposite the fibula ; the four lesser toes are on the side opposite the tibia. Now, the muscle that bends the great toe flexor longus hallucis arises from the posterior surface of the fibula, middle one-third ; likewise, the muscle that bends the four lesser toes the flexor longus digitorum arises from the posterior surface of the tibia, middle one-third. To gain their insertions they cross in the sole of the foot in the second layer ot muscles of this region. (Fig. 270.) The flexor longus hallucis traverses four grooves. (Fig. 268.) The flexor longus hallucis needs special mention. It passes through (i) a little groove on the posterior part of the tibia (Fig. 208) ; (2) through a pronounced one on the narrow posterior surface of the astragalus ; (3) through a well-marked groove on the under part of the sustentaculum tali of the os calcis (Fig. 268) ; (4) through a groove between the two sesamoid bones,, in the tendon of the flexor brevis hallucis at the metatarso-phalangeal articulation. This muscle is inserted into the base of the distal phalanx of the great toe. (Fig. 268.) Trace the popliteus muscle to its origin. (Fig. 266.) Detach it at the ob- lique line of the tibia, its insertion, and trace it between the outer tuberosity and head of fibula, under the external lateral ligament of the knee and the biceps, to the outer side of the external condyle of the femur. Structures under Internal Annular Ligament. From the internal malleo- lus to the os calcis : (i) Tendon of tibialis posticus, next the malleolus ; (2) ten- don of flexor longus digitorum ; (3) a sheath of connective tissue containing the posterior tibial nerve and artery, with a vein on each side of the artery ; (4) behind this sheath, and deeply buried in its three upper grooves, above referred t<>, is the tendon of the flexor longus pollicis. In the dissection of the sole of the foot these several structures will be traced to their various destinations. The Peronei Longus and Brevis ( Figs. 266 and 269). These two muscles occupy almost the entire outer surface of the fibula. Commonly, the origin is as follows : the longus from the upper one-third and the brevis from the middle one-third. (Fig. 207.) The muscles are separated in front and behind from adjacent musculatures by intermuscular septa. They pass under the external annular ligament, immediately behind the malleolus, and are inserted : ( f) the brevis into the base of the fifth metatarsal ( Fig. 269) ; (2) the longus pa>ses through a groove on the under surface of the cuboid bone, then through an osseo-aponeurotic canal, to the base of the first metatarsal bone. (Fig. 275.) These muscles are supplied by muscular branches of the nnusculo-cutaneous IH.TVC, a branch of the external popliteal. (Fig. 264.) These muscles, when POSTERIOR PART OF LOWER EXTREMITY. 385 acting together, assist the tibialis posticus in extending the ankle. They are antagonized by the tibialis anticus and peroneus tertius. THE SOLE OF THE FOOT. (Fig. 272.) The importance of a knowledge of this region can not be overestimated. The large number of important structures in a comparatively small area, com- bined with thick skin, dense plantar fascia, and delicate lumbrical muscles, all taken Origin of abductor minimi digiti Part of abductor minimi digiti Plexor brevis minimi digiti Abductor minimi digiti Lumbricales Tendon of flexor brevis digitorum Flexor brevis digitorum Abductor hallucis Accessorius Flexor longus digitorum Flexor lougus hallucis Flexor brevia hallucis Adductor hallucis Abductor hallucis Tendon of flexor brevif- digitorum FIG. 270. SECOND LAYER OF THE MUSCLES OF THE SOLE. tog-ether make dissection of this area somewhat difficult. A dissection of the o four layers of muscles alone would be an easy task, but here, as in larger areas of the body, nerves and vessels must be saved. The only general rule I can give you is this : Follow painstakingly as a guide the dissections given in the text, and learn from the figures what you expect to find. Having done this, follow each nerve and vessel out carefully to its distribution. No number of written pages will make an awkward man improve his touch ; hence it is impossible to 3 86 PRA CT1CAL ANA TOM\ '. do more than suggest to the student that he should early learn to cultivate a delicate touch. It requires but little effort with the forceps to divide the delicate connective tissue that surrounds all vessels and nerves, and intervenes between muscles. In the sole of the foot you will find, in this order, from without in- ward, the following structures : 1. The thickest skin of the body on the sole of the foot. 2. Superficial fascia, very thick, containing granular fat. 3. The deep or plantar fascia, with its three divisions. Abductor minimi digit! Flexor brevis minimi digiti Tendon of flexor longus digitorum Plexor brevis digitorum Abductor liallucis Flexor longus hallucie Flexor brevis hallucis First lumbricalis Tendon of adductor hallucis FIG. 271. FIRST LAYER or mi: MTSCLES OF THE SOLS, 4. The first layer of muscles: The abductor hallucis, the flexor brevis digi- torum, and the abductor minimi digiti. 5. 'I'lic internal and external plantar nerves and vessels. (Fig- 272.) 6. The second layer of muscles : The tendon of flexor longus hallucis and a slip of contribution to the flexor longus digitorum ; tendons of the flexor longus digitorum ; the musculus accessorius and lumbricales ; the nerve- and blood- supply to these muscles. 7. Hie third layer of muscles : Flexor brevis hallucis and its sesamoid bones ; abductor hallucis muscle ; flexor brevis minimi digiti muscle; transversus pedis muscle ; nerve- and blood-sup] >!y to these muscles. POSTERIOR PART OF LOWER EXTREMITY. 387 8. The fourth layer of muscles: Dorsal interossei, four in number; plantar interossei, three in number ; the nerve- and blood-supply to these. (Fig. 275.) 9. The tendon of tJic pcroncus longus and its sesamoid bone. (Fig. 275.) Incisions. Start at the middle of the os calcis and make one cut through the skin to the middle of the great toe ; the other to the middle of the little toe. This V-incision will permit you to find : i. The plantar cutaneous nerve, a branch of the posterior tibial nerve. Abductor hallueis Flexor brevis digitorum INTERNAL PLANTAR NER YE Internal plantar artery BRANCH OF INTER- NAL PLANTAR NERVE TO INNER SIDE OF HALL UX Abductor minimi digit! External plantar artery EXTERNAL PLANTAR NER VE Ligameuta vaginales DIGITAL COLLATERAL BRANCHES OF EX- TERNAL PLANTAR DIGITAL COLLATERAL BRANCHES OF INTER. NAL PLANTAR FIG. 272. SUPERFICIAL XKKVES IN THE SOLE OF THE FOOT. (Ellis.) (In this dissection the greater part of the plantar fascia has been removed.) (Fig. 272.) This is a sensory nerve to the heel, and you will find it in the thick pad of fat in the superficial fascia. Sometimes the granular fat here is three- fourths of an inch thick. 2. The cutaneous branches of the internal and external plantar vessels and nerves. Exercise now your common sense in removing the skin. The superficial fascia contains much fat. The fat found in the palms of the hands, in the soles of the feet of the adult, and all over the body of the child at 88 PRACTICAL ANATOMY. term, is called granular. Remove all this fatty tissue, and notice it becomes less abundant in the hollow of the foot and toward the toes. The deep fascia occurs in the sole of the foot, under two names : (i) From the heel to the clefts of the toes it is called plantar fascia ; (2) from the clefts of the toes onward it forms very dense sheaths for the flexor tendons of the toes. These sheaths are called the ligamenta vaginales (ligamentum vaginalis, in the singular). Dissection of Plantar Fascia and Ligamenta Vaginales. Having now cut through the dense, deep fascia of the toes, the ligamenta vaginales, you External calcanean artery Cutaneous branch of external plantar * Abductor minimi digit! Anastomolic branch External plantar artery Pint digital to outer side of lillle, lot Lumbrieal muscle Second digital Third digital Fourth digital Anastomosis about inter- phalangeal joint Dorsal branch of collateral digital Anastomosis of collateral arteries around matrix of nail and pulp of toe Internal calcanean artery Cutaneous branch of internal plantar Plantar fascia, cut Abductor ballucia Internal plantar artery Flexor brevis digitorum Branch of internal plantar to iliiiilnl tirfcries (superficial digital] Flexor brevis hallucis Princeps hallucis, or fifth plantar digital artery Collateral digital branch of princeps hallucis to second toe Collateral diiiiinl branch // AofitCdfefO iinn-r si. (From a dissection in the Museum of St. Bartholomew's Hospital.) must find : (i) The theca ajid the thecal culs-de-sac, the synovial sheath of the tendons ; (2) the vincula, delicate thread-like bands of deep fascia ; (3) the ten- dons of the flexor longns digitorum ; (4) the tendons of the flexor brevis digi- torum ; (5) the slits, in tendons of the flexor brevis digitorum ; (6) the grooves on the plantar surfaces of the pedal phalanges ; (7) the outer division of tin- plantar fascia, quite thin, covering the abductor minimi digiti muscle ; (8) the inner division of the plantar fascia, quite thin, covering the abductor hallucis ; (9) the middle division of the plantar fascia, very thick, strong, and glistening, covering the flexor brevis digitorum ; (10) two intermuscular grooves almost under tin- POSTERIOR PART OF LOU'ER EXTREMITY. ?8g \J s diverging; branches of the V-incision you made in the skin. You will notice that the three divisions of the plantar fascia correspond to the three muscles in the first layer, cover them, and in great part are almost inseparably connected there- with. (Fig. 273.) The plantar fascia is part of the origin of these muscles. Remove this fascia (Figs. 281 and 273) and trace out with the forceps the branches of the internal and external plantar nerves and vessels. (Fig. 272.) The plantar fascia has a central part that covers the flexor brevis digitorum ;. an outer portion that covers the abductor minimi cligiti, and is continuous with the dorsal fascia of the foot externally ; an inner portion that covers the abductor Part of abductor minimi cligiti Flexor brevis minimi digit! Trans versus pedis Divided tendons of flexor brevis digitorum Long plantar (long inferior calcaneo-cuboid) ligament Flexor longus hallucis Flexor longus digitorum Tibialis posticus Flexor brevis hallucis Adductor hallucis Tendon of the flexor longus hallucis Tendon of flexor longus digitorum FIG. 274. THIRD LAYER OF THE MUSCLES OF THE hallucis, and is continuous internally with the dorsal fascia of the foot. Poste- riorly, the plantar fascia is attached to the os calcts ; anteriorly, it is continuous with the ligamenta vaginales. Muscles of the First Layer (Fig. 273). Dissect carefully in the grooves between the middle muscle and the muscles on each side of it. Trace all three muscles back to their origins on the os calcis. (Fig. 268.) Likewise trace each forward to its insertion : the abductor liallucis to the base of the first phalanx of the great toe (Fig. 268) ; the abductor minimi digiti to the base of the first phalanx of the little toe ; the flexor brci'is digitorum to the second phalanges of the four lesser toes, by cutting through the ligamenta vaginales the long 390 PRACTICAL ANATOMY. way of the tendon. (Fig. 268.) Now cut all three of these muscles and turn them forward, and expose the second layer of muscles. (Fig. 270.) Having cut through the ligamenta vaginales of the toes (Fig. 272), observe that the four tendons of the flexor longus digitorum pass through slits in the four corresponding tendons of the flexor brevis digitorum, in the same manner the deep flexors of the fingers pass through the superficial ones. Second Layer (Fig. 270). In the figure of the flexor longus digitorum notice three accessories: (i) The muscular acccssorius (Fig. 268) ; (2) the four limibricales (Fig. 273); (3) a slip of contribution from the tendon of tlie flexor longus Iiallueis. (Fig. 270.) Having studied the origin and insertion of these muscles, divide the flexor longus hallucis and flexor longus digitorum near the os calcis and turn them all forward, as you did the previous layer. Third Layer (Fig. 274). Trace out to its origin each one of the three mus- cles inserted into the base of the great toe. Cut down between the two sesamoid bones in the tendon of the flexor brevis hallucis. Trace the tendon of the peroneus longus across the sole of the foot to its insertion into the internal cunei- form and base of great toe metatarsal. (Fig. 275.) In the fourth layer we have the dorsal interossei and the plantar interossei. In number they are seven, four being dorsal and three plantar. In action they are analogous to the interossei of the hand. In the foot they are all supplied by the external plantar nerve ; in the hand by the ulnar nerve. Function of the Interossei and Lumbricales. It is comprehensive to consider the action of these muscles in this manner in the hand : 1. All the interossei and lumbricales acting together, flex at the metacarpo- phalangeal articulation and extend at the first and second phalangeal articula- tions. This gives about the position for'holding the pen. 2. The four dorsal interossei acting alone, abduct the digits. Notice that supination of the forearm is involuntarily associated with abduction of the digits. 3. The palmar interossei acting alone, adduct the digits. Notice that prona- tion of the forearm is associated involuntarily with adduction of the fingers. In the above I have described the action of these muscles in the hand ; the action in the foot is the same, only less under control of the will, since the foot of man is not a prehensile member. 4. The adductor line of fingers and toes. The adductor finger is the middle ; the adductor toe is the second. In adduction and abduction the other digits approach and recede from this adductor digit. The Adductor Digit. (i) The adductor digit of the hand has no palmar interossei inserted into it ; (2) the adductor digit of hand has two dorsal inter- ossei inserted into it ; the same is true of the foot. Difference in Origin. Notice that the dorsal interossei are very large, and arise from the contiguous sides of the metatarsals or metacarpals ; that the palmar are small, and arise from one side only of the metatarsal or metacarpal corresponding to the phalanx into which they are inserted. Practise the movements of the lumbricales and interossei on your own fingers until you master this subject thoroughly. Granular Fat. Found in the superficial fascia of the hand and foot palmar and plantar surfaces and in the general supi-rficial fascia of the f(utus and infant. Tin- toughness of this kind of fatty tissue depends on a largi r amount of con- nective tissue. Divisions of Plantar Fascia. (i) An outer thin one that covers the ab- ductor minimi digiti. (2) An inner one that covers the abductor Jiallneis. (3) A middle one that covers the flexor bre:_ o G W Sixth layer, . . Seventh laver, Trapezius. Nerve-supply, spinal accessory, cervical plexus. Levator anguli scapulae. Nerve-supply, cervical plexus. Rhomboideus minor. Nerve-supply, brachial plexus. Rhomboideus major. Nerve-supply, brachial plexus. Latissimus dorsi. Nerve-supply, the long subscapular. Serratus posticus superior. 1 Nerve-supply, posterior divisions of spinals, Serratus posticus inferior, j external branches. Splenius capitis. ) Nerve-supply, posterior divisions of spinals, external Splenius colli. } branches. Outer division (nerve-supply, all by posterior divisions, spinal nerves) : 1. Ileo-costalis. 2. Musculus accessorius ad ileo-costalem. 3. Musculus cervicalis ascendens. Middle division (nerve-supply, posterior divisions of spinals) : 1. Musculus longissimus dorsi. 2. Musculus transversalis colli. 3. Musculus trachelo-mastoideus. Inner division (nerve-supply, posterior divisions of spinals) : Musculus spinalis dorsi. Musculus complexus. Nerve-supply, suboccipital, great occipital, posterior division. Semispinalis colli. Nerve-supply, posterior divisions of spinal. Semispinalis dorsi. Nerve-supply, posterior divisions of spinal. Rotatores spinae. Nerve-supply, posterior divisions of spinal. Multifidus spinae. Nerve-supply, posterior divisions of spinal. Interspinales. Nerve-supply, posterior divisions of spinal. Intertransversales. Nerve-supply, posterior divisions of spinal. Occipital Group (nerve-supply, suboccipital nerve). Rectus capitis posticus minor, rectus capitis posticus major, rectus capitis lateralis, obliquus superior, obliquus inferior. Nerve-supply, great occipital and suboccipital nerves. ANALYSIS OF THE SIMPLE MOVEMENTS OE THE SPINAL COLUMN AND THE MUSCLES WHICH PRODUCE THEM. View the skeleton from behind, and note the juxtaposition of spines, laminae, transverse processes, articular processes, and bodies or centra of vertebrae. Note the head of the rib articulating with the body, and the tubercle of the rib articulat- ing with the transverse process of a vertebra. (Fig. 276.) Each is a movable articulation, because it has a synovial sac. Note the central pulpy nature of the intervertebral disc. Note the manner in which the head of the rib articulates with two bodies and the cartilaginous disc, and recall the exceptions to this rule in the first, ninth, tenth, eleventh, and twelfth thoracic vertebrae. (Fig. 277.) SIMPLE MOVEMENTS OF THE SPINE. 1. Lateral flexion of the column by the intertransversales. 2. Extension of the column by the interspinalcs and spinalis dorsi. 3. Lateral rotation by the rotatores spinae, extending from the transverse pro- cess of the vertebra below to the lamina of the bone above. 4. Extension and lateral rotation of the column by the multifidus spinae, in a typical region extending from the transverse processes of the vertebrae below, to the lower border of the spines above, from the last lumbar to the second cervical vertebrae. Note that extension and lateral rotation are the two most common move- 39 6 PRACTICAL ANA TOM}. merits of the human vertebral column ; that there are three regions where this movement is specially pronounced: (i) the tlioracic region; (2) the ccrrical region ; (3) the region between the head and neck. Anterior costo-central or stellate ligament Costo-central synovial sac Laminar portion of inter- vertebral disc Central pulpy portion of inter- vertebral disc Middle costo-trana- verse ligament Costo-transverse synovial sac Posterior costo-transverse ligament FIG. 276. HORIZONTAL SECTION THROUGH THE INTERVKRTEURAL Disc AND RIBS. The interartioular ligament The superior or anterior costo-transverse ligament! The stellate ligament FIG. 277. SIIOWIM; THE ANTERIOR COMMON LICAMI.M <>i mi MMNE, AND mi ( > >.\ SECTION OF THE RlBS WITH 1111 \KRTEBR>E. The semispinalis dorsi, semispinalis colli, and complexus are accessory to the multifulus spin;r. Note the means to an end, then, in (i) the semispinalis dorsi (Fig. 285) ex- tending from transverse processes to the spines in such a manner as to strengthen the dorso-rervical junction. The scinispinalis colli is likewise disposed to THE BACK. 397 strengthen the same region. So we will see that from the transverse processes of all the dorsal vertebrae to the spines of all the dorsals and cervicals there is a continuous, uninterrupted plane of oblique muscular fibres. (Fig. 285.) They are called semispinales dorsi and colli. They are synergistic physiologi- cally to the multifidus spinae only a larger edition of the same. Their function is extension and lateral rotation. Note, again, there is an upward continuation of this same muscular arrange- ment to the head the complexus, a semispinalis capitis. (Fig. 283.) It arises from the transverse processes of the upper six thoracic and last cervical, and is Trapezius INION OR EXTERNAL-OCCIPITAL PROTUBERANCE SUPERIOR NUCHAL LINE Occipito-frovitalia MIDDLE NUCHAL LINE Sterno-mastoid SpleniuB capitis Eectus cap. post. min. Rectus cap. post. maj. Superior oblique INFERIOR NUCHAL LINE Eectus capitis lateralis POSTERIOR CONDYLOID FORAMEN JUGULAR PROCESS BASI-OCCIPITAL FIG. 278. THE OCCIPITAL. (External view.) inserted into the occipital bone. Its action is extension and lateral rotation of the head. The above are the simple movements of the vertebral column. Complex movements may be had by combination of different simple movements. I have spoken of the mechanism in advance of the dissection, to inspire the student to greater care in his work. NERVES THAT SUPPLY THE BACK. 1. Tlie long subscapnlar nerve to the latissimus dorsi (brachial plexus). 2. The spinal accessory nerve to the trapezius (twelfth cranial nerve). 3. T/ie snboccipital nerve to the complexus, recti, and oblique muscles. 4. Muscular branches from the cervical plexus to the rhomboids and levator anguli scapulae. 5. Posterior divisions of the spinal nerves, thirty-one pairs to other muscles. 6. The great occipital nerve, to the complexus muscle and to the scalp. Scheme for the Posterior Divisions of the Spinals. All except the first cervical divide into internal and external branches ; the internal branches sup- ply the sixth and seventh layers, the external branches the remainder ; they 39 8 PRACTICAL ANATOMY. all supply the skin of the back ; there are twelve dorsal cutaneous nerves ; the suboccipital is the first cervical posterior division ; the great occipital is the posterior division of the second cervical ; the third occipital is a branch of the third cervical, posterior division. You will find the (i) suboccipital nerve in the suboccipital triangle ; (2) the great occipital under the complexus muscle crossing the suboccipital triangle ; (3) the spinal accessory nerve between the trapezius and sterno-mastoid muscles ; (4) the third occipital internal to the great occipital ; (5) the suboccipital emerges between the occipital bone and atlas behind the vertebral artery ; (6) the great occipital nerve emerges between the atlas and axis and passes under cover of the complexus muscle through the lower and inner part of the suboccipital triangle ; (7) the great occipital nerve joins the occipital artery under the trapezius and lies on the complexus muscle ; (8) other posterior divisions emerge between the transverse processes. Arteries of the back are: (i) the dorsal branches of all the intercostals ; (2) the deep cervical, a branch of the superior intercostal ; (3) the arteria prin- ceps cervicis, a branch of the occipital ; (4) these arteries, represented by num- bers 2 and 3, anastomose under the complexus. The student who studies in advance of his dissection the foregoing pages will have no difficulty in making a thorough dissection of the back. Dissection. Locate : (i) The spinous processes of the vertebra in the dorsal and lumbar regions ; (2) the iliac crest ; (3) the crest of the scapular spine ; (4) the three lips of the crest of the scapular spine ; (5) the acromion process of the scapula ; (6) the external occipital protuberance ; (7) the vertebra proinincns ; (8) the angles of the ribs, and note the distance they are from the spinous processes; (9) the iliac junction with the sacrum ; (10) the rudimentary sacral spines ; (i i) the ma stoid processes ; (12) the clavicle ; (13) the twelfth rib. Incisions. (i) From external occipital protuberance to the rudimentary sacral spines ; (2) from one acromion process of the scapula to the other. Begin to remove the skin at the intersectional point of the vertical and horizontal inci- sions just made. Observe the cutaneous nerves piercing the trapezius and latissimus dorsi, on removing the skin. These are the cutaneous branches of the posterior divisions of the spinal nerves. (Fig. 279.) Note the very heavy variety of the superficial fascia. This, you will observe, is tightly bound to the deep fascia by fibrous trabeculaj that make removal of the skin difficult. This fascia, especially in the region of the neck, is a common place for boils and carbuncles. Observe the great depth you will have to cut to get through this fascia. Clean all the superficial fascia off and make your work look like figure 22~ . Here you have exposed two muscles : (i) The trapo/ius ; (2) the latissimus dorsi. The Trapezius. Trace its origin to the external occipital protuberance, the inner third of the superior nuchal line, the ligamentum nuclijc, the seventh cer- vical spine, and all the dorsal spines. Now pull the arm outward (Fig. 280), and put the muscle on the stretch. Study its descending fibres to the outer third of the clavicle and acromion ; its ascending and horizontal ones to the upper lip of tin- spine of the scapula. Develop the lower margin of the trape/.ius muscle, and observe that it overlaps the latissimus dorsi. Find the space between the trapezius and sterno-cleido-mas- toid muscle. Locate in this space the spinal accessory nerve, and trace the THE BACK. 399 same to the trapezius. Also trace the nerve upward to where it comes through the sterno-cleido-mastoid muscle. Latissimus Dorsi. Trace the origin to the six lower thoracic spines, lum- Semi-apinalis Multifldus spinae LongissimuB dorai Ilio-oostalia Rhomboideua major Latiaaimua dorsi Gluteus maximus FIG. 279. DISTRIBUTION OF THE POSTERIOR PRIMARY DIVISIONS OK THE SHXAI. NERVES. (Henle.) bar aponeurosis, and iliac crest, posterior one-third ot outer lip. Develop the upper border and expose the infraspinatus and teres major in the triangle formed by this muscle, the deltoid, and the trapezius. (Fig. 280.) Develop with the scissors the lower border of the muscle. The latissimus dorsi will be inserted into the poste- 400 PRACTICAL ANATOMY. nor lip ofthe bicipital groove of the humerus with the major tereal muscle. These two muscles, the trapezius and the latissimus dorsi, may now be removed by cut- ting through their origins, tracing the same carefully to their respective inser- tions, where they may be detached, when you will have exposed (Fig. 281) : 1. The musculus levator anguli scapulae. 2. The musculus rhomboideus minor. 3. The musculus rhomboideus major. 4. The musculus splenius capitis. 5. The musculus complexus. 6. The musculus serratus posticus inferior and superior. 7. Vertebral aponeurosis. 8. The occipital artery on the complexus muscle. 9. The great occipital nerve. Now develop with scissors the four serrations of insertion into the lower four ribs of the serratus posticus inferior. This muscle arises from the spines of the eleventh and twelfth thoracic, and the first and second dorsal vertebrae. Pull the arm outward, and put the rhomboids on the stretch. Study their insertion into the middle lip of the vertebral border of the scapula. Develop their spinous origin. (Fig. -281.) Cut the rhomboids near their origins and turn them outward. (Fig. 281.) See the nerve-supply on the under surface near the centre. See also the pos- terior scapular artery, a continuation of the transversalis colli artery. The rhomboideus minor (Fig. 281) arises from the spine of the seventh cervical and first thoracic vertebrae, and from the ligamentum nuchae. It is inserted into the vertebral border of the scapula opposite the spine. Its nerve- supply is from the brachial plexus. The rhomboideus major (Fig. 281) arises from the five upper thoracic ver- tebrae and their supraspinous ligament, and is inserted into the middle lip of the vertebral border of the scapula from a point opposite the spine above to the in- ferior angle below. The nerve-supply is from the brachial plexus. The action of the rhomboids is to lift the scapula upward, backward, and inward. Levator Anguli Scapulae (Fig. 281). Pull the arm outward and find the in- sertion of this muscle into the middle lip of the vertebral border of the scapula above the spine. Trace its three or four tendons of origin to the anterior tubercles of the transverse processes of the four upper cervical vertebrae. This muscle deri\ is its nerve-supply from the cervical plexus. Its action is to elevate the scapula and. by producing rotation of the same, it depresses the point of the scapula. Serratus Posticus Superior (descending fibres) (Fig. 282). This muscle lies under the levator anguli scapulae and rhomboids. It arises by aponeurosis from the seventh cervical spine and the upper three dorsal spines. It is inserted into the second, third, fourth, and fifth ribs, a little beyond the angle. The nerve-supply is from the posterior primary divisions of the second and third intercostals. The serratus posticus inferior (ascending fibres) (Fig. 282) arises, by aponeurosis, from the two lower dorsal and three upper lumbar spines; it is inserted into the four lower ribs a little beyond the angle. Notice the difference between the two serrati museles. The upper is inserted into the upper border, the lower into the lower border of ribs. The Vertebral Aponeurosis (Fig. 2X2). Internally you see this aponeurosis alt. idled to the spines ; externally it is attached to the angles of the ribs ; below it blends with the serratus postieus inferior and latissimus dorsi ; above it passes behind the superior serratus. It separate's the proper muscles of the back from those that act on the shoulder girdle. The Splenius Capitis and Colli. Develop the long, pointed origin of this THE BACK. 401 Triceps Teres minor Ini'raspinatus Teres major Bhotnboideus major Pectoralis major Obliquus externus Gluteus mediu Gluteus maximus FIG. 280. FIRST LAYER OF MUSCLES OF THE HACK. 402 PRACTICAL ANATOMY. muscle from the sides of the spines of the seventh cervical and six upper dorsal vertebne. (Fig. 281.) The muscle has two insertions: (i) into the mastoid Supraapinatus Obliquua interims Complexua Splenius oapitii Levator anguli scapulae Serratua posticus superior Rhomboideus minor Spleniua colli Rhomboideua major 281. 'I'm l.i \ \iou AM. ri. i SCAPULA AM> RHOMBOIDEI. process of the temporal bone ; (2) into the posterior tubercles of the transverse- processes of the three upper cervical vertebrae. The nerve-supply is from the posterior primary divisions of the cervical nerves. THE BACK. 43 Erector Spinae and Branches. Remove the vertebral aponeurosis (Fig. 282) and expose the fifth layer of muscles and its subdivisions. (Fig. 283.) Complexus Splenius capitia Splenius colli Serratus postieus superior Vertebral aponeurosis Serratus postieus inferior Obliquus interims Origin of latissimus dorsi SEVENTH CERVICAL VERTEBRA TWELFTH THORACIC VERTEBRA FIFTH LUMBAR VERTEBRA FIG. 282. THE THIRD AND FOURTH LAYERS OF THE MUSCLES OF THE HACK. Origin. (i) The spines of the two last thoracic, all the lumbar, and the four upper sacral vertebrae ; (2) the back of the side portion of the fourth sacral 404 PR A CTICAL ANA TOMY. vertebra; (3) the posterior sacro-iliac ligament, a few of these fibres being continuous with the origin of the gluteus maximus ; (4) the upper part of the ComplexuB Trachelo-mastoid Traneversalis colli Longissimuo dorsi Accessor-jus ad ilio- ooatalein Spinalis dorsi Ilio-costalis Obliquus internus Erector epinae SEVENTH CERVICAL VERTEBRA TWELFTH THORACIO VERTEBRA FIFTH LUMBAR VERTEBRA IMC;. 283. Tin. KII-TII I.AYKK OF TDK Mfsci.Es UK run HACK. posterior superior spine of the ilium, and the posterior fifth of the iliac ere. 1 (Morris). THE BACK. 405 Insertion. It is continuous abov r e with the spinalis dorsi, longissimus dorsi, and ilio-costalis. Locate the spinalis dorsi first, the inner insertion of the erector spinae muscle. Remember it takes its origin from the inner part of the erector spinae. Trace its tendons of insertion to the spines of the upper thoracic vertebrae. Locate the groove between the outer and middle divisions of the erector spinae. In this groove you will find the external branches of the posterior divisions of the spinal nerves, in company with the dorsal branches of the inter- costal vessels. Turn the muscles apart, as in figure 284. The outer division of the erector spinae is called ilio-COStalis, to its insertion into the angles of the lower ribs, from the sixth to the eleventh rib. It is continued upward through the back and neck as (i) the accessorius, (2) cervicalis ascendens. Accessorius ad ilio-costalem arises from the angles of the ribs, seventh to eleventh, and is inserted into the angles of the ribs from the second to the fifth, and into the transverse process of the seventh cervical vertebra. Cervicalis ascendens arises from the ribs fourth to fifth upper internal to the costal insertion of the accessorius, and is inserted into the posterior tubercles of the fourth, fifth, and sixth cervical transverse processes. The middle division of the erector spinae continues through the thorax under the name of longissimus dorsi ; through the neck, to the head, as the trans- versalis colli and trachelo-mastoid. (Fig. 284.) The longissimus dorsi arises: (i) From the middle part of the erector spinae ; (2) from the transverse processes of some of the lower thoracic vertebras. It is inserted into : (i) The ribs external to their tubercles ; (2) the transverse processes of the thoracic vertebras ; (3) into the accessory tubercles of the upper lumbar and lower thoracic vertebrae ; (4) into the transverse processes of the upper lumbar vertebrae. Transversalis colli arises from the transverse processes of the upper six thoracic vertebrae, internal to the insertion of the longissimus dorsi. It is in- serted into the posterior tubercles of the transverse processes of the vertebrae from the second to the sixth cervical vertebrae inclusive. The trachelo-mastoid (Fig. 284) is the inner part of the transversalis colli continued in the mastoid process. In some cases this muscle is unusually well developed. The sixth layer of muscles comprises the following : 1. The complexus, or semispinalis capitis. 2. The semispinalis dorsi in the dorsal region. 3. The semispinalis colli in the cervical region. 4. The multifidus spinae, found in all regions of the spine. 5. The rotatores spinae, found in the thoracic region. Describe the complexus muscle. This muscle (Figs. 283 and 284) is covered by the splenius, with its two divisions, and the trapezius. In turn, this complexus covers the muscles that make the boundaries of the suboccipital triangle, thereby forming the roof of this important surgical area the suboccipital triangle. The occipital artery lies on the muscle ; the suboccipital and great occipital nerves are under the muscle, being parts of the contents of the suboccipital triangle. The origin of the muscle is from : (i) The articular processes of the cervical vertebra? from the third to the sixth ; the transverse processes of the seventh cervical and the six upper thoracic vertebras. The insertion is into the occipital bone, between the middle and inferior curved or nuchal lines. (Fig. 278.) Nerve-supply: (i) The suboccipital or posterior primary division of the first cervical ; (2) the great occipital or posterior primary division of the second cervical ; (3) the posterior primary divisions of the third, fourth, and fifth cervical nerves. 406 PRACTICAL ANATOMY. Obliquua superior Rectus capitis posticus major - Obliquus inferior Trachelo-mastoid Transversalis oolli Cervicalis ascendena Accessorius ad ilio- costalem Ilio-costalis Insertion of ilio-costalia upon lumbar transverse processes Rectus capitis posticus minor SEVENTH CERVICAL VERTEBRA LongisBirnus dorai TWELFTH THORACIC VERTEBRA FIFTH LUMBAR VERTEBRA Erector spinae IMG. 284. TIIK FII-TII LAYKK OF IMF MUSCLKS Of mi- BACK, AI-TER SITAKATINC; HIK i H I I l: AM) MlMUI.K DlV|sM>NS. THE BACK. 407 Describe tlic semispinalis dorsi. The idea in the name is founded on the facts : (i) That one of the muscle is inserted into the spines, and (2) that the muscle is situated in the thoracic or dorsal region of the spine. (Fig. 285.) The muscles composing the series are small and tendinous. They extend obliquely inward and upward, from their origin, on the back of the transverse processes of the thoracic vertebrae, from the sixth to the tenth, to their insertion into the spines of the last two cervical and the first, second, third, and fourth thoracic. The nerve-supply is from the posterior primary divisions of the thoracic nerves. Remove this muscle and you expose the multifidus spinae below. The muscle is covered by the spinalis dorsi and latissimus dorsi the inner and middle parts of the erector spins, you will remember. Describe tJie semispinalis colli. The verbal idea is the same in this as in the preceding muscle. The muscle is located in the cervical region ; it is inserted into the spines of the cervical vertebrae, from the second to the fifth inclusive. (Fig. 285.) The muscle originates from the transverse processes of the five or six upper thoracic vertebrae. The muscle is covered by the complexus ; under it is the multifidus spinae. Between the complexus and semispinalis colli you will find : (i) Branches of the posterior cervical nerves ; (2) an anastomosis between the arteria princeps cervicis, a branch of the occipital, and the arteria profunda cervicis, a branch of the superior inter- costal. In ligatfon of the common carotid and subclavian arteries blood may reach both the hand and brain by this channel. Describe the nmltifidus spines. The multifidus spinae is found in every region of the spine. In the sacral and lumbar regions it is thick and fleshy ; in the thoracic and cervical regions it is thin and aponeurotic. This muscle has the following origins, which must be carefully learned before this muscle can be dissected understandingly : (i) From the deep surface of the erector spinae. This fact of origin makes the dissection of the muscle a difficult task, except in cases of zinc or formaline pre- pared bodies where the cadavers have had a year to become very hard ; (2) from the groove between the sacral spines and rudimentary articular processes of the sacrum ; (3) from the mammillary processes of the lumbar vertebrae ; (4) the transverse processes of all the thoracic vertebrae ; (5) the articular processes of the cervical vertebrae from the fourth to the sixth, and from the transverse process of the seventh cervical. The segments making up the collective multi- fidus spinae from these diverse regions are inserted as follows : into the lower borders of the vertebral spines, from the fifth lumbar to the second cervical. The nerve-supply of the multifidus spinae is from the posterior primary divisions of the spinal nerves, from the second cervical to the third sacral nerve. This muscle covers the rotatores spinae. Describe the rotatores spiiue. These are in the region of the thorax. They derive their name from the rotatory action they exert. Of these muscles there are eleven pairs. They originate from the back and upper part of the transverse processes, and are inserted into the lower border of the lamina of the next vertebra above. They are in relation above with the multifidus spinae. Nerve-supply, the posterior primary divisions of the spinals. Name and describe the seventh layer of muscles of the back. (i) The interspinales arise from the upper surface of the spine of a lower, and are inserted into the lower surface of the spine of the vertebra immediately above. These muscles are very small. Nerve-supply, the posterior primary divisions of the spinals. (2) The intertransversales arise from the transverse process below and are inserted into the one above. They are small muscles. 408 PRACTICAL ANATOMY. They are principally in the cervical and lumbar regions. Nerve-supply, from the spinals as they emerge from the intervertebral foramina. Compleius Obliquua superior Reotua capitia poaticua major Obliquua inferior Multifldua spinae Semispinalia oolli Cervioalia aacendens LonKiaaimus dorsi Levator eoatse Longiesimus dorai Ilio-ooataliB Obliquus internua Lumbar fascia Ilio-coatalia Kectua capitis poaticub minor SEVENTH CERVICAL VERTEBRA Semispmalis dorai Multifldua apinae TWELFTH THORACIC VERTEBRA Multifldua apinae FIFTH LUMBAR VERTEBRA Itifldus spiuce l-ii.. 285. TIIK SIMM I.AM'.K en- TIII-: Mi M i.i-s 01 im-. I;\CK. I. The Complcxns. Remove the longissimus dorsi and its continuation through the neck and to the head the transvcrsalis colli and the trachdo- THE BACK. 409 mastoid. The complexus will be seen arising from : (i) The back of the artic- ular processes of the cervical vertebrae from the third to the sixth ; (2) the back of the transverse processes of the seventh cervical and the six upper thoracic vertebrae ; (3) generally also by an inner head from the spine of the seventh cer- vical vertebra. It is inserted into the occipital bone, between the superior and inferior nuchal lines. (Fig. 283.) Carefully detach the insertion of this muscle and you will expose : (i) The suboccipital triangle, containing the vertebral artery and the suboccipital nerve ; (2) on the under part of the muscle you will find the suboccipital nerve and the great occipital nerve ; (3) the recti and oblique muscles ; (4) the semispinalis colli, coming to a large abrupt insertion into the spine of the axis. The suboccipital triangle has (Fig. 285) : A roof formed by the complexus muscle. A floor formed by the arch of the atlas and atlo-occipital ligament. An inner border formed by rectus capitis posticus major. A lower border formed by inferior oblique muscle. An upper border formed by superior oblique muscle. The contents are the vertebral artery and suboccipital nerve. It is traversed by the great occipital nerve. The suboccipital muscles (Fig. 285) : 1. The obliquns capitis inferior, which extends from the spine of the axis to the transverse process of the atlas. 2. The obliquns capitis superior, which extends from the transverse process of the atlas to the inferior nuchal line of the occipital bone. 3. The rectus capitis posticus major, which extends from the spine of the axis to inferior nuchal line, middle one-third. 4. The rectus capitis posticus minor extends from the tubercle of the atlas to the inner one-third of the inferior nuchal line. 5. The rectus capitis later alls extends from the lateral mass of the atlas to the jugular process of the occipital bone. Now remove from its origin (i) the complexus, and as you turn the body of the muscle from the semispinalis colli, you will see between these two muscles some vessels the anastomosis between the arteria profunda cervicalis, a branch of the first or superior intercostal, and the arteria princeps cervicis, a branch of the occipital. (Fig. 40.) You will find a large mass of veins here, too. In cases of ligation of the subclavian or common carotid artery, this is the principal channel by which the blood passes to form a collateral circulation. (2) Remove any remaining part of the spinalis dorsi or longissimus dorsi and make your work look like figure 285. You have remaining the other members of the sixth and seventh groups : (i) The semispinalis dorsi ; (2) the semispinalis colli; (3) the multifidus spinae. These were explained under the head of " Analysis of the Simple Movements of the Spinal Column," to which you are referred on page 395. Remove the three muscles just given, and dissect (4) the rotatores, (5) the intertransversales, (6) the interspinales, according to their previous description, just referred to. i . Give the cutaneous nerve-supply of the back. The scalp is supplied by (i) the great occipital ; (2) the suboccipital ; (3) the third occipital. These are all spinal nerves. The remainder is supplied by the posterior divisions of the spinal nerves. Next the spine you will see some small nerves coming through to the skin. (Fig. 279.) These are cutaneous twigs from the internal branches of the posterior divisions of the spinal nerves. A little distance from the spine you will see nerves coming through the trapezius and latissimus dorsi. These are the external cutaneous branches of the posterior divisions of the spinal nerves. 27 410 PRACTICAL ANATOMY. 2. Explain internal and external brandies of t/ie posterior divisions of tJie spinal nerves. The internal branches are small, and supply the sixth and seventh groups of muscles and the skin on each side of the spine for an inch or two inches. The external branches supply all the other proper muscles of the back and the remainder of the skin. All the thirty-one pairs of posterior divisions of spinal nerves divide as previously indicated, except the first. This is called the suboccipital nerve. 3. Define ivhat is meant by proper muscles of the back. All those muscles not acting on the shoulder girdle ; those under the verte- bral aponeurosis. 4. Give a description of the superficial fascia of the back. It is very thick and dense, and contains granular fat. Abscesses often form here. A favorite place for carbuncles is in the superficial fascia of the neck. 5. Name the muscles of the back not supplied principally by the posterior divi- sions of the spinal nerves. The trapezius, the latissimus dorsi, the levator anguli scapulae, and the rhom- boids, major and minor. SHORT SUMMARY OF THE CRANIAL NERVES. Hoiv arc the cranial nerves classified ? According to the new classification of cranial nerves there are twelve pairs, enumerated serially from before backward, from the olfactory, or first, to the hypoglossal, or twelfth, inclusive. This classification was proposed by Soemmer- ing in 1778. Prior to this time the classification of Willis had been in use for more than a century, by which classification only ten pairs were recognized. Make a further distinction between the classifications of the cranial nerves by Socmmcring and Willis. In the seventh pair Willis included both the/ada/, a nerve of motion, and the auditory, a nerve of the special sense of hearing. The eighth pair of Willis included the ninth, tenth, and eleventh nerves of our classification. The ninth pair of Willis included the hypoglossal, and the tenth pair of Willis included the first cervical, called the suboccipital nerve. What is understood by superficial and deep origins of cranial nerves f By the former is meant the place where the nerve is seen attached to the surface of the brain (Fig. 92) ; by the latter is- meant the place deeply located, called a nucleus of gray matter, to which the motor part of nerves can be traced. Docs not tlie sensorv part of nerves also have a deep origin f Properly speaking, the sensory parts of nerves have their origin in the cells of the posterior root ganglia of the nerve-trunks, to which ganglia special atten- tion must be given in the dissection of both cranial and spinal nerves. The sensory fibres originating in the ganglia grow inward to this nuclei, and, as far as is known, form there no direct connection with the nerve-cells. Is there any correspondence between the origins of the cranial nerves and the origins of the spinal nerves f Yes ; each has a superficial and a deep origin. The superficial origin of the spinal nerves is readily seen on removing the spinal cord from its neural canal. The deep origin of the spinal nerves is from tin- anterior and posterior horns of the gray crescents of the interior horns of the spinal cord. \VItat further resemblance between crania/ and spinal nerves may be mentioned / (l) Fibres from the deep origin of eaeh pass upward and are connected with the cortex of the cerebrum ; (2) the pneumo^astric nerve arises by motor and sensory roots from nuclei which are derivatives of the anterior and posterior THE BACK. 411 horns respectively of the spinal cord ; (3) the ganglion on the sensory root of the fifth cranial nerve and the ganglion on the root of the vagus are homologous to the ganglia on the posterior roots of the spinal nerves ; (4) cases are recorded of absence of the ganglion on the posterior root of the first spinal or suboccipital nerve ; (5) cases are recorded of the hypoglossal the twelfth cranial nerve having a posterior root with a ganglion. Possibly anomalous cases like those cited in 4 and 5 may account for and even justify the tenth cranial nerve the hypoglossal in the classification by Willis. In iv hat respects do spinal nerves differ from cranial nerves / In the following respects : (i) Spinals arise from the spinal cord ; (2) spinals have an anterior motor and a posterior sensory root ; (3) spinals have a ganglion on each posterior root ; (4) spinals have no special sense nerves. State where the ganglia of the posterior or sensory roots of the spinal nerves may be found in dissecting. The rule is that these ganglia occupy the posterior root of the spinal nerve, just behind the union of the anterior and posterior roots, in the intervertebral foramen. Are there any exceptions to the rule governing the location of the spinal ganglion / Yes ; the ganglia of the first and second cervical nerves lie on the neural arches of the atlas and axis. The ganglia of the sacral and coccygeal nerves are in the spinal canal. Describe the vagus or pneumogastric nerve. This nerve is the tenth cranial, according to the classification of Soemmering ; it is also called the nervus vagus and the nervus par vagam. The nerve leaves the base of the cranium by the central part of the jugular foramen with the spinal accessory and glosso-pharyngeal nerves. Where is the ganglion of the root of the vagus located, and to what does it corre- spond morphologically ? It is located in the jugular foramen, and corresponds to the spinal ganglion on the posterior roots of the spinal nerves. What is the importance of the ganglion of the root of the vagus nerve ? It has connections with the sympathetic, spinal accessory, glosso-pharyngeal, and facial nerves. (Fig. 293.) Where is the ganglion of the trunk of the vagus nerve and ivliat its impor- tance ? It is a little below the ganglion of the root and below the base of the skull. Its importance is due to the fact that branches are given off from it to the sympa- thetic, to the cervical nerves, and to the hypoglossal nerve ; also the accessory part of the spinal accessory nerve joins the vagus at this point. (Fig. 293.) Describe the olfactory nerve. The olfactory nerve, as generally understood, is in reality a dismembered part of the fore-brain of the foetus. It consists of four parts, as may be appreciated by consulting figure 286. 1. The olfactory roots, three in number. 2. The olfactory tract, a slender bundle. 3. The olfactory bulb, resting on the cribrosa. 4. The olfactory filaments, about twenty in number. Name and give the source of the olfactory roots. The middle root is attached to the under surface of the frontal lobe ; the internal root to the gyrus fornicatus ; the external root to the temporo-sphenoidal lobe. The roots meet to form the olfactory tract. The tract becomes bulbous and occupies a fissure on the under surface of the frontal lobe of the cerebrum, called the olfactory sulcus. The olfactory nerves are given off from the under 412 PRACTICAL ANATOMY. part of the bulb. The nerves are about twenty in number on each side. They pass through the olfactory foramina in the cribriform plate of the ethmoid bone. In their course through the foramina, the nerves are invested by a sheath of dura mater. (Fig. 87.) The olfactory nerve filaments are distributed to the mucous membrane of the upper and middle turbinated bones, and to a corre- sponding part of the septum nasi. (Fig. 75.) Describe tJie optic nerve. This nerve is the special nerve of sight, being distributed solely to the eye- ball. The commissure is the place on the sphenoid bone where the two sides ffulA Ot feretory filaments FIG. 286. FIRST CRANIAL NERVE, OLFACTORY. are connected. The optic nerve proper is between the commissure and the eye- ball ; the optic tract is between the commissure and the brain. Describe the optic tract. It arises (Fig. 92) : (i) From the pulvinar of the optic thalamus ; (2) from the geniculate body ; (3) from the upper quadrigeminal body. The tract crosses the crus cerebri (Fig. 92), being closely attached thereto, and terminates in the optic chiasma or commissure. The student will recall the fact that the optic chiasma and the optic tracts assist the crura cerebri and pons Varolii in forming the boundaries of the interpeduncular space. (Fig. 92.) Longitudinal Fibers- Decussating Fibers Intcrcerehral Fibers Inter-retinal Fibers FIG. 287. SECOND CRANIAL NIRVK, Orru. Describe the optic ncri'c proper. This nerve extends from the chiasma to the eyeball. It leaves the cranium by the optic foramen, in the sphenoid bone, in company with the ophthalmic artery. The nerve has a cranial part and an orbital part ; the latter is flexuous, to accommodate the movements of the eyeball, and is surrounded by ciliary vessels and nerves. /// practical anatomy i^Iicrc do you find tJic artcria ccntralis retuuc / This must In- seen in a dissection of the contents of the orbit. (Fig. 103.) You will find this artery piercing the under part ojf the nerve, and about midway between the optic forair.en and the globe. THE BACK. 413 The she at J i of the optic nerve is derived from what source / It is derived from the dura mater coming through the optic foramen and de- laminating ; one layer ensheathes the optic nerve, the other forms the orbital periosteum. (Fig. 95.) The third cranial nerve the motor oculi supplies : (i) The ciliary muscle of the eyeball ; (2) the sphincter muscle of the iris ; (3) all the muscles of the eye- ball except the superior oblique and the external rectus. This nerve arises beneath the floor of the aqueduct of Sylvius. On removing the brain from the cranium, you see the nerve between the crura cerebri. (Fig. 92.) The nerve pierces the dura midway between the anterior and posterior FIG. 288. THIRD CRANIAL NERVE, MOTOR OCULI. clinoid processes, and enters the cavernous sinus ; in the sinus it lies above and internal to the fourth nerve. (Figs. 8688.) The nerve divides behind the sphenoidal fissure into a superior and an inferior division. (Fig. 86.) These two divisions enter the orbit by the sphenoidal fissure, passing between the two heads of the external rectus muscle. (Fig. 101.) The superior division supplies the superior rectus muscle and the levator palpebrae ; the inferior division has the remaining part of the distribution of the third nerve. \VJiat can yon say of the fourth cranial, or patJieticns? It is also called the trochlear nerve, from the fact that it supplies the superior oblique muscle of the eyeball only. This nerve has a long course in the cranial cavity. In dissection you see the nerve just under the margin of the anterior FIG. 289. FOURTH CRANIAL NERVE, TROCHLEAR. free border of the tentorium cerebelli, and soon piercing the dura to the outer side of the posterior clinoid process, to gain the cavernous sinus. (Fig. 98.) This nerve is the smallest of the cranial nerves ; it enters the orbit by the sphe- noidal fissure. The nerve has its 'deep origin in the floor of the aqueduct of Sylvius. Describe briefly the fifth cranial or trifacial nerve. This nerve is specialized almost exclusively for the prehension and mastication of food directly or indirectly. It will be noted that the relation between this and other nerves depends upon the near or remote association these latter bear to the functions of the fifth nerve. Take notice, then, of the function of the trigeminus, 414 PRACTICAL ANATOMY. as follows : (i) The fifth nerve supplies with sensation all the teeth. (2) The fifth nerve supplies with sensation the gums, by little nerves called the nervi gingivales. (3) The fifth nerve supplies the sides of the tongue, and the anterior one-half of the same through its lingual or gustatory branch. (4) The fifth nerve supplies the muscles of mastication with motion muscles whose function is to move the mandible. (5) The fifth nerve supplies the temporo-mandibular articulation, be- cause the muscles it supplies move this articulation. The same branch that sup- plies the articulation, the auriculo-temporal, also supplies the drum of the ear and the auditory canal, because these parts are secondary in the acquisition of food. (6) The fifth nerve supplies the skin covering the fullest region of the FIG. 290. FIFTH CRANIAL NI.KVK. muscles of mastication ; in round numbers, the cutaneous region in front of a line passing from side to side through the auditory meatuses is supplied by the auri- culo-temporal, supraorbital, infraorbital, and mental branches of this nerve. (7) The fifth nerve supplies the anterior belly of the digastric muscle and the mylo- hyoid muscle, but these muscles are depressors of the mandible. (8) The fifth nerve has numerous connections with the facial nerve. Study the facial anil temporal relations between these- two nerves ; tin- chorda tympani ; the otic, sub- maxillary, and Meckel's ganglia. The trifacial nerve supplies the muscles of mastication with motion, and the skin covering these muscles. ll'/itif can you .sv/r of tlic si.vtli cranial )icrvc / This nerve is distributed solely to the external rectus muscle. It arises from THE BACK. 415 the floor of the fourth ventricle. It may be seen in dissection piercing the dura below and internal to the fifth nerve. (Fig. 88.) In the cavernous sinus the nerve lies on the outer side of and is attached to the internal carotid artery. (Fig. 88.) In the sinus the sixth nerve is joined by sympathetic filaments from the cavernous plexus, and receives a twig from the ophthalmic branch of the fifth nerve. (Fig. 98.) The Seventh or Facial Nerve. (i) Leaves the cranium by the internal audi- tory meatus in company with the auditory or eighth cranial nerve and the audi- tory artery, a branch of the basilar artery. (2) In the internal auditory canal it is connected to the auditory nerve by the pars intermedia, and enters a separate bony canal, called the aqueductus Fallopii, one-quarter of an inch from the in- ternal auditory meatus. (3) On nearing the tympanum the nerve turns sharply backward and presents an enlargement, called the intumescentia gangliformis (gen- Supnavrbifal 3?! 1 FIG. 291. SEVENTH CRANIAL NERVE, FACIAL, OR PORTIA DURA. Great petrosal, to form Vidian with No. 5. 2. Small petrosal, to otic ganglion. 3. External petrosal, to plexus on mid-meningeal artery. 4. Tympanic branch to stapedius, etc. 5. Branch from carotid plexus making Vidian, with No. I. 6, 7. Branches to auriculo-temporal of fifth. 8. Branch to auricular of vagus. M. The ganglion of Meckel. O. A. F. Orifice of aqueductus fallopii. iculate ganglion). (4) From the geniculate ganglion are the following branches : (a] The large superficial petrosal to Meckel's ganglion. This branch leaves the cranium by the foramen lacerum medium, and joins a branch from the carotid sympathetic plexus, called the large deep petrosal, to form the Vidian nerve. (/?) The small superficial petrosal to the otic ganglion. This nerve leaves the cranium by the canalis innominatus, a small opening between the foramen ovale and the foramen spinosum, in the greater wing of the sphenoid bone. This branch receives a communicating twig from the tympanic branch of the glosso-pharyn- geal nerve, (r) The external superficial petrosal nerve, to join the sympathetic on the middle meningeal artery. (5) The facial nerve traverses the middle ear in its bony canal, traversing between the roof and inner wall, and between the inner wall and the posterior, successively, emerging at the stylo-mastoid foramen. (6) In the middle ear the nerve gives off (a] a small branch to the stapedius muscle ; (b] the chorda tympani, which supplies the submaxillary and sublingual 416 PRACTICAL ANATOMY. glands with secretory and vaso-dilator fibres, and the anterior part of the tongue with taste fibres. The facial supplies the stylo-hyoid, the posterior bell}- of the digastric, all the dermal muscles about the ear, the posterior belly of the occipito- frontalis, and all the muscles of facial expression. (7) The facial nerve commu- nicates with the three divisions of the fifth on the face ; with the spheno-palatine. otic, and submaxillary ganglia ; with the auditor}', vagus, sympathetic, and glosso- pharyngeal nerves. Dcsoibc briefly the auditory nerve. This is the eighth cranial nerve. It leaves the cranium by the internal auditory meatus with the auditory artery a branch of the basilar and the seventh or facial OPHTHALMIC SUPERIOR MA.\I I.L.I I! Y 1. \7-7-.7.' ini; MAXILLA I! Y \ GASSEJ;I.\\ x.i/.iA.A. FICIAL I'ETHOSAI. //r 7.1 A, r. i. v.i A /.s . TUBARIVS FENESTRA OVA US AM> ROTUNDA I\ Till': /.V.V /;/.' MM I.L FACIAL NERVE EXTERNAL SUPERFICIAL PETROSAL ANTERIOR WALL POSTERIOR WALL FIG. 292. Box ILLUSTRATION OF SEVENTH CRANIAL NERVK IN RELATION TO THE MIDDLE EAR OR TYMPANUM. For puqx>ses of aiding ihe memory, the tympanum is compared to a box. The reader is referred to page 135 for a full description of the figure. nerve. In the auditory canal it communicates with the seventh nerve by the pars intermedia. The eighth is the nerve of the special sense of hearing. (For the distribution of this nerve see Morris.) Describe the glosso-pliaryngeal nerre. This is the ninth cranial nerve. It escapes from the cranium by the jugular foranu-n with the tenth and eleventh nerves and the jugular vein. The nerve has two ganglia: (i) The jugular and (2) the petrosal ganglion. The ninth nerve distributes branches to the mucous membrane of the tongue, pharynx, tympanum, and also to the stylo-phary ngeus muscle. It supplies the otic gano- lion ria its communications with the small superficial petrosal branch of the THE BACK. 417 seventh nerve. This nerve communicates with the third division of the fifth nerve ; with the facial, sympathetic, and vagus. What can you say of the function of the vagus ? In animals less highly specialized than man the term pneumogastric expresses practically all that can be said of this nerve, since in its wandering distribution it supplies the organs of voice and respiration with motion and sensa- tion ; the organs of circulation and digestion with motion only. The vagus, then, has to do with the two greatest sources of metabolism : the ingestion of food and air. Man is not all stomach and lung. By synecdoche, however, stomach may represent a complicated digestive apparatus, and lung an equally differ- entiated apparatus, in which the blood throws off CO 2 and loads up with O, according to the law of the diffusion of gases. Now, the student must remember this : The names of the branches of the vagus nerve will be governed and deter- mined by the following conditions : 1. The arbitrary subdivision of the alimentary canal, to which the vagus is distributed. 2. The arbitrary subdivisions of the respiratory system, to which the vagus is distributed. 3. The sympathetic nerve-branches to both the respiratory and digestive systems, since the sympathetic is the nerve of organic life. 4. The organs, or systems of organs, associated secondarily with the respira- tory and digestive processes. The tongue, for example, is associated with both respiratory and digestive processes, and while this organ has its own specific nerve- supply, upon which its sensation and motion depend, still, the orderly adjustment of internal to external relations could not occur, were there no communication between the nerve-supply of the tongue, which forces food into the pharynx, and the organs that deliver this food to the stomach. In like manner there must be unanimity of action between the lungs, vocal cords, and tongue, for vocalizing and linguistic purposes ; this unanimity must depend on an uninterrupted communi- cation between the nerve-supply of the tongue and the vagus nerve. Observe the difference in facial expression of the two men, the one of whom is in the nausea period of a malarial attack, the other of whom is enjoying an after-dinner cigar. The facial nerve supplies the muscles of expression, and by its communi- cation with the vagus both comfort and distress in the stomach are facially expressed. PHYSIOLOGICAL REASONS FOR THE NUMEROUS COMMUNICATIONS OF THE VAGUS NERVE. 1 . With the spinal accessory nerve. The spinal part of the spinal accessory nerve is distributed to the sterno-cleido-mastoid andtrapezius muscles, and assists in forming the cervical plexus. It will be remembered that the mission of the cervical plexus is to supply the diaphragm and certain muscles of forced respira- tion, as well as the depressor muscles of the hyoid bone. (Page 73.) 'Now, the accessory part of the spinal accessory nerve supplies the muscles of the soft palate. Thus, by the communication between the vagus and the spinal acces- sory, harmony is established between the muscles that rhythmically enlarge and reduce the size of the thorax, and the lungs that occupy this thorax, and by their rhythmic movements carry on vocal and respiratory processes. 2. I Vith the petrous ganglion of the glosso-pharyngcal or ninth cranial nerve. This nerve has a distribution as follows : (i) To the tongue ; (2) to the pharynx via the pharyngeal plexus ; (3) to the middle ear, Eustachian tube, and mastoid cells via the tympanic plexus ; (4) to the parotid gland via its small superficial petrosal branch and the otic ganglion ; (5) to the facial nerve ; (6) to the sympa- 418 PRACTICAL ANATOMY. thetic nerve. In the communications, then, between the pneumogastric and the glosso-pharyngeal nerve, we see the connecting link between a mechanism pumping air, under the direction of the vagus, and a territory to be constantly he B 1 ^ Pair of Nerves comprising the 9*. h or G I os so- pharyngeal 10V or Pneumogastnc, . 1 1 l . h or Spinal Accessory. Terminal Brs , fivm Tetteri Com/undofAnntomij. IK;. 293. EIGHTH J'AIR UK CRANIAL NERVES. i. Jugular ganglion of ninth nerve. 2. Petrous ganglion of ninth nerVe. 3. Ganglion of the vagus root. 4. Ganglion of the vagus trunk. 5. Medullary part of eleventh nerve. 6. Spinal part of eleventh nerve. 7. Superior cardiac branch joining cardiac of sympathetic. 8. Subclavian artery, mi right tide, arch of the aorta, on lefi side <>f the l><>dy. <>. Koramen magnum, receiving spinal par) of the spinal arct^-ory. IO. Jugular l.-iainrn , transmitting all tlircc nerves; also (ailed the foramen laeeium pdsterius. ii. Branches to hypoglossal, sympathetic, cervical nerves. 12. Olivary body (in broken line). ventilated the middle ear and Kustachian tube, a territory whose delicate structures might be invparably (lania-cd, \vrre not the sensor)' sentinel, the tympanic plexus, thnv i<> ri'L'.ul.itf the ingress and egress of air. And note, too, THE BACK. 419 the expression of anguish on the patient's face when the middle ear is the seat of pain ; an expression determined by the auricular communicating branch of the ninth nerve with the seventh or facial nerve, and also with the pneumogastric nerve, as represented in figure 293. 3. Wit I i the Jiypoglossal nerve, by which the movements of the tongue are harmonized with both deglutition and vocal action. 4. WitJi the sympathetic nerve, by which the action of the heart and lungs may be brought into harmony with their environment. The physiological communications of the vagus nerve are : 1. With the spinal accessory nerve. 2. With the glosso-pharyngeal nerve. 3. With the hypoglossal nerve. 4. With the sympathetic nerve. 5. With the first and second cervicals. 6. With the facial or seventh cranial nerve. This communication is for the purpose of harmonizing respiration and the ingestion of food, in their broadest terms, in consonance with a conservative and aesthetic adjustment of inner to outer relations. Name the brancJics of the vagus nerve. 1. A recurrent branch to the dura mater. 2. The auricular branch, given off from the ganglion of the root, is joined by a branch of the petrous ganglion of the glosso-pharyngeal. (Fig. 293.) This branch divides into two : one communicates with the posterior auricular branch of the facial, the other joins the facial nerve in its canal. The auricular branch of the tenth cranial nerve is called Arnold's nerve. 3. The pharyngeal is the prime motor nerve of the pharynx. It unites with the glosso-pharyngeal, superior laryngeal, and sympathetic branches to form the pharyngeal plexus. The principal fibres of the pharyngeal branch of the pneumo- gastric are derived from the accessory part of the spinal accessory nerve. 4. The superior laryngeal nerve is the nerve of sensation to the mucous mem- brane of the larynx, and of motion to the crico-thyroid muscle. 5. The inferior laryngeal nerve is the motor nerve to all the intrinsic muscles of the larynx except the crico-thyroid. This is also called the recurrent laryn- geal. 6. The cervical cardiac branches communicate with the sympathetic, and pass to the superficial and deep cardiac plexuses. 7. The thoracic cardiac branch has a double origin : (i) From the trunk of the vagus ; (2) from the recurrent laryngeal nerve. They are distributed to the cardiac plexus. 8. The anterior pulmonary branches unite with the sympathetic to form the anterior pulmonary plexus, which is found on the front of the root of the lung. 9. The posterior pulmonary branches unite with sympathetic nerves to form the posterior pulmonary plexus. This is larger than the preceding, and found on the posterior part of the root of the lung. (Fig. 151.) 10. The cesophageal plexus supplies the oesophagus and pericardium. It is formed by the union of branches from both the right and left pneumogastric nerves. The plexus is also called the plexus guise, because gula means gullet. 1 1. The terminal branches are the gastric. The branches from the left vagus supply the anterior, those from the right the posterior, surface of the stomach. They unite with the sympathetics and assist also in forming the splenic and hepatic plexuses. Describe tJie spinal accessory nerve. This is the eleventh cranial nerve. It leaves the cranium by the jugular foramen with the ninth and tenth nerves and the internal jugular vein. It has : 420 PR A CTICAL ANA TO MY. (i) A spinal part and (2) an accessory or internal part. The spinal part you will trace to the trapezius and sterno-mastoid muscles. The accessor}' part passes forward to the superior laryngeal nerve and pharyngeal plexus. Describe tlic hypoglossal or twelfth nerve. This is the motor nerve of the tongue. It leaves the cranium by the anterior condyloid foramen. It supplies the depressor muscles of the hyoid bone in association with the first three cervical nerves. It communicates with the vagus, lingual, sympathetic, and upper three cervical nerves. ARTICULATIONS. LIGAMENTS. 1 . WJiat is an articulation ? Union of bone to bone, bone to cartilage, or cartilage to cartilage, by means of modified periosteum called ligaments. 2. What are some of the ends subserved by articulations / Stability, as in the joints of the cranium ; motility, as in the extremities ; semistability, as in the pelvis and vertebral column. 3 . Name and indicate the function of the structures found in a typical articula- tion for motility. (i) There is bone for strength and solidity ; (2) a shell or covering of bone, free from vessels and nerves, adapted to bear pressure ; (3) a highly polished articular cartilage to confer elasticity and reduce friction ; (4) a capsular ligament, of periosteal derivation, attached above and below the joint to the bones party to the articulation ; (5) a synovial membrane, with its articular vessels and nerves, closely investing the interior of the capsule, for the secretion of synovia. 4. Name the structures found in an articulation intended for stability. Bones with variously shaped edges, whose union in the very young is legal- ized by periosteum called sutural ligament. 5. Name structures found in an articulation wlicrc semistability is to be attained. Bony surfaces firmly united by discs of cartilage, which admit of slight motion, and under certain physiological conditions as pregnancy develop par- tial synovial membrane. 6. Are there any technical terms by zvhich tlie artiadations, as above classed, are designated / SVNARTHROSIS includes all immovable articulations where bone is joined to bone by variously shaped borders, as toothed, grooved, scaled, sawlike, and seam- like. AMPHIARTHROSIS includes all articulations in which bone is firmly united to bone by cartilage, with slight movement, as in the pelvis and vertebral column, and a spasmodic production of synovia, as the case may require ; as in pregnancy, this may be the case. DIARTHROSIS includes all articulations with perfect capsules, free movement, and constant production of synovia. 7. Does the degree of motion vary in articulations ? Yes ; and the following subdivisions of the class diarthrosis express the variety or kind of movement, in accordance principally with the degree of motion, as determine'd by the shape of the articular surfaces : (i) Enarthrosis, or ball- and-socket variety, in which there is movement in four modified angular direc- tions. Examples of this are seen in the hip, shoulder, and carpo-metacarpal articulation of the thumb. (2) Condylarthrosis, in which free movement, as in the ball-and-socket articulation, is inhibited. Instance, the temporo-maxillary, occi- pito-atlantal, radio-carpal, metacarpo-phalangeal, and metatarso-phalangeal joints. In each, as you may demonstrate on yourselves, there is free movement as flexion and extension in two directions, but very limited movement from side 421 422 PRACTICAL ANATOMY. to side. Observe the free movement of the fingers on the metacarpals forward and backward, and the limited movement from side to side. The movement of lower jaw is the same. We can see plainly that this variety of joint is a com- promise between ball-and-socket and the hinge -joint. (3) Ginglymus, or hinge- joint t in which there is free movement in two directions, as in the elbow, knee, ankle, and interphalangeals of all the digits of both feet and hands. In these articulations note the impossibility of lateral movement without violence ; note the intermediate position between this variety and the ball-and-socket variety, occupied by the preceding condylarthrosis subdivision. (4) Lateral ginglymns is a term used to express a subdivision of movable joint which differs from the hinge movement in no essential, except in the direction of motion. The supe- rior and inferior radio-ulnar articulations and the atlanto-oclontoid belong to this subdivision. (5) Arthrodia includes the simplest subdivisions of all the movable articulations. In this kind the surfaces are plane, or nearly so. The movements are limited, by virtue of the strong and unyielding nature of the liga- ments, which represent the lowest organized variety of capsular ligament. Kx- amples of this subdivision are in the carpal and tarsal articulations ; between the metacarpals and metatarsals ; in the articular processes of the vertebrae ; in the costo-transverse and interchondral articulations. I desire you to dissect and study the movable articulations the diarthroses according to the following outline : 1 . Give the name of the class diarthrosis, for example. 2. Give the name of the subdivisions of the class. 3. Give the technical name of the locality. 4. Give the osteological units in the joint. 5. Give subdivisional parts of osteological units. 6. Name the articular surfaces according to the rule. 7. Give the basis of a movable joint a capsule. 8. Give the local subdivisions of the capsule. 9. Name the strengthening bands of the capsule, if any. 10. Name the incorporated tendons of obsolete muscles, if any. 1 1. Name the bony limitations of movements of the joint. 12. Name the nerve-supply and blood-supply of the joint. 13. Name the ligamentous muscles of the joint. Let us review now the above outline, and understand its specific scope. 1. There are five subdivisions of the class diarthrosis. (Page 424.) Ky examining the articulation, you find movement in two directions. Your entry should read : Class, diarthrosis ; Subdivision, ginglymus. 2. Let us assume the particular joint is the elbow : then the technical name- is humero-radio-ulnar articulation ; the common name, elbow-joint. 3. The osteological units in this joint are the humerus, radius, and ulna. 4. The subdivisional parts of the osteological units are the outer and inner humeral condyles, radial head of humerus, head of radius, olecranon process of ulna, coronoid process of ulna, greater sigmoid cavity of ulna. 5. Articular surfaces should take the name of the occupant. Then in this joint we find the radial and ulnar surfaces of the humerus ; the humeral surfaces of the ratlins and ulna. The ulnar surface of the humerus is called technical!}' the trochlear or pulley surface ; the radial surface of the humerus is called the capitcllum, or link- head. 6. The basic principle in every movable joint is a capsule derived from peri- osteum, linrd by a more or less extrusive synovial membrane. 7. The subdivisions of the capsule are anterior, posterior, internal lateral, ami external ligaments. A complete capsule is equal to the sum of its subdivisional parts. The usage by which capsules are thus subdivided is a useless (except ARTICULA TIONS. LIGAMENTS. 4 2 3 for locating lacerations in rare instances) as well as an arbitrary practice. There is no well-defined line of demarcation between a lateral and an anterior part of a capsule, as the student may expect to find, since transitions in anatomy are easy and gradual. 8. Strengthening or accessory bands are derived either from the deep fascia or from the aponeurosis of a muscle crossing a joint. 9. By incorporation of tendons in a capsule, the capsule becomes stronger where the incorporation occurs. Growth is the correlative of function, you will remember ; now, if from change in environment an animal acquire altered body movements, a muscle may migrate from its primitive insertion below a joint to an acquired insertion above a joint. Loss of function entails loss of specific char- acter ; in this case loss of specific character that is, loss of muscular element leaves only the connective-tissue framework crossing the joint. The muscle migrated, the tendon became divorced, and by vigorous retrogression of muscle, a band of connective tissue remains which strengthens the capsule ; the original tendon became incorporated with the capsule. The divorced tendon of the adductor magnus obtains as the internal lateral ligament of the knee-joint ; that of the peroneus longus as the external lateral ligament. The coraco-humeral ligament is the divorced tendon of the minor pectoral muscle. The greater sacro-sciatic ligament is the divorced tendon of the biceps femoris. The liga- mentum teres in the hip-joint is said by Morris to be in all probability the divorced tendon of the pectineus muscle. 10. The movements of joints are often limited by bone. Note should be taken of these physiological limitations on the cadaver when you dissect liga- ments. 1 1. Ligamentous muscles to a joint are such muscles as cross a joint. The biceps, brachialis anticus, triceps, and all the muscles getting origin from the 'humeral condyles are ligamentous in their action to the elbow-joint. Muscles as the rectus femoris and the sartorius may be ligamentous to more than one joint. Ligamentous muscles are also called the elastic ligaments of a joint. 12. Note the entrance of nerves and vessels that supply the synovial mem- brane. Such structures are designated articular. In this connection refer to Hilton's law governing articular nerves. This law is given in the introductory chapter of this book on page 19. 13. Finally, having found in the make-up of movable joints bone, articular lamella, cartilage, ligament, tendon, muscle, synovial membrane, nerve, and blood-vessels, be able to classify these structures histologically, according to the outline given in the beginning of this work under caption of anatomical tissues. The plan just outlined for your guidance will not only give you a thorough un- derstanding of the ligaments, but will refresh your memory on those very prac- tical points you will so much need in your subsequent medical studies, both as students and as practitioners of medicine. Whenever you are in doubt as to the name of a particular subdivision of a class, consult the following table, taken from Morris : TABLE OF THE VARIOUS CLASSES OF JOINTS. Class. Examples. I. Synarthrosis (a) True sutures Lambdoid, sagittal, coronal. (^) False sutures Internasal. Intermaxillary. Costo-chondral. (c) Grooved sutures Vomer and rostrum of sphenoid. II. Amphiarthrosis Bodies of vertebras. Symphysis pubis, sacro- iliac, sacro-coccygeal. 424 PRACTICAL ANATOMY. TABLE OF THE VARIOUS CLASSES OF JOINTS. (Continued.') Class. III. Diarthrosis (a) Enarthrosis . . . (b} Condylarthrosis . (c) Ginglymus or Trochlearthrosis . (d) Trochoides or Lateral Ginglymus (tJr t 'isioii(i/ /W/'/.v. Head of ulna, sigmoid of radius. (Fig. 246.) ARTICULA TIONS. LIGAMENTS. 435 6. Articular Surfaces. Ulnar of radius, radial surface of ulna. 7. Basis. A modified capsule, lined by synovial membrane. 8. Local Parts of Capsule. An anterior radio-ulnar, posterior radio-ulnar, triangular fibro-cartilage. 9. Strengthening Bands. None ; periosteal purely. 10. Incorporated Tendons of Obsolete Muscles. None. 1 1. Blood-supply. Anterior interosseous and anterior carpal. (Fig. 247.) 1 2. Nerve-supply. Anterior and posterior interosseous. 13. Ligamentous Muscles. Pronator quadratus and supinator longus. Locate and give the attachments of the anterior radio-ulnar ligament. It is attached to the radio-ulnar triangular fibro-cartilage and styloid process. It is located on the anterior part of the bones. Locate and give the attachments of the posterior radio-ulnar ligament. It is attached to the radius, ulna, and triangular fibro-cartilage anteriorly and posteriorly. Posterior radio-carpal ligament Capsule of carpo-meta- carpal joint of thumb Posterior radio- ulnar ligament Internal lateral ligament of wrist FIG. 305. POSTERIOR VIEW OF WRIST. THE RADIO-CARPAL ARTICULATION. 1. Class. Diarthrosis, because of free motion and a capsule. 2. Subdivision. Condylarthrosis, because rotation on a vertical axis is wanting ; /. t\, there is no axial rotation. 3. Teclinical Name. Radio-carpal articulation. 4. Osteological Units. Radius, scaphoid, semilunar, cuneiform, cartilage. 5. Subdivisional Parts of Units. None. 6. Articular Surfaces. According to the general rule. 7. Basis. A modified and highly specialized capsule. 8. Local Parts of Capsule. Anterior, posterior, internal, external. 9. Strengthening Bands. None ; purely periosteal. 10. Incorporated Tendons of Obsolete Muscles. None. 11. Bony Limitations. Radial and ulnar styloids. 1 2. Blood-supply. Anterior and posterior carpal arterial arches. 13. Ligamentous Muscles. (i)The flexors of the carpus, on radius and ulna ; (2) the extensors of the carpus, on radius and ulna ; (3) the sublime and pro- 43 6 PRACTICAL ANATOMY. found digital flexors ; (4) the flexor longus pollicis ; (5) the extensor communis digitorum ; (6) the special extensor of the little finger ; (7) the special extensor of the index finger; (8) the three extensors of the thumb. Total, 14. Explain fully tJie most important ligament in the radio-carpal articulation. The most important is the triangular fibro-cartilage. It may be described as having : (i) A base, attached to the margin of the radius ; (2) an apex, attached to the fossa at base of ulnar styloid ; (3) an anterior border, attached to radio- Synovial sac of the inferior radio- uluar joint Synovial sac of the carpus Synovial sac, occasionally separate, for the fourth and fifth metacar- pal bones Synovial sac of the wrist-joint Synovial sac of the carpo- metacarpal joint of the thumb Lateral ligaments of the metacarpo- phalangeal. and inter-phalangeal joints !'!(;. 306. SYNOYIAI. MKMBRANKS OK \\KIM, HAM>. \M> I-INC.KKS. carpal and radio-ulnar ligaments ; (4) a posterior border, attached to the radio- carpal and radio-ulnar ligaments; (5) an upper or ulnar articular surface (con- cave) ; (6) a lower or cuneiform surface (concave). 1 !<>:,< does tltis cartilage differ from all otlier Jihro-eartiln^es. It niters into the formation of two distinct articulations, the inferior radio- ulnar and radio -Carpal, separating them completely. /I'//// lioio ninny hones does the end of tlie radius articulate f With the scaphoid and scmilunar. ARTICULA TIONS. LIGAMENTS. 43 7 Give tlic attachments of the internal lateral ligament of the radio-carpal articu- lation. Its apex is attached to the styloid process of the ulna ; its base to the pisi- form and cuneiform bones, and to the anterior annular ligament. Give attachments of the external lateral ligament of the radio-carpal articulation. Its apex is attached to the apex of the radial styloid process ; its base to the scaphoid and trapezium. Give the attachments of the anterior radio-carpal ligament. It is attached above to the radius and anterior radio-ulnar ligament ; below, to the two rows of carpal bones. Give the attachments of the posterior radio-carpal ligament. It is attached above to radius, styloid, and fibre-cartilage ; below, to the first row of carpal bones. Does the synovial cavity of the radio-carpal articulation communicate with the in- ferior radio-ulnar or carpal articulations ? No. CARPAL ARTICULATIONS. How may we consider the carpal articulations ? (i) The joints of the first row consisting of four short bones ; (2) the joints of the second row consisting of four short bones; (3) the junction of the two rows called the medio-carpal joint. Name the short bones in the first and second rows. The scaphoid, semilunar, cuneiform, and pisiform ; trapezium, trapezoid, os magnum, and unciform. Name the ligaments of the first row. They are all connected by two dorsal and two palmar and two interosseous ligaments to each other, except the pisiform. How may the pisiform bone be regarded ? It may be regarded as a sesamoid bone developed in the tendon of the flexor carpi ulnaris, and connected by a capsule to the cuneiform bone. How are the bones of the second row united ? By three dorsal, three palmar, and two interosseous ligaments. The articu- lations of the first and second rows belong to the diarthrodial class and arthrodial subdivision of joints. Name the ligaments of the medio-carpal articulation. These are the anterior, posterior, medio-carpal, and transverse dorsal ligaments. To dissect this region cut through dorsal ligaments. Give the attachments of the anterior annular ligament. Internally it is attached to the unciform process of the unciform bone, and the pisiform bone ; externally, to the scaphoid and trapezium. How many insertions has the flexor carpi ulnaris ? Three : (i) Into the pisiform bone ; (2) into the unciform process of the unci- form bone ; (3) into the base of the fifth metacarpal. Trace the tendon of the flexor carpi radialis to its insertion. It passes through a groove in the os trapezium, and is inserted into the base of the second metacarpal, sometimes also into the third as well. How are the carpo-metacarpal articulations classified ? (i) Into an outer, corresponding to the thumb ; (2) four inner, corresponding to the remaining four digits. Wliv are they so classified .' Because they belong to different subdivisions of the class diarthrosis. The carpo-metacarpal of the thumb is a saddle-shaped arthrodia ; the others are simply arthrodia. 438 PRACTICAL ANATOMY. Name tJic ligaments of the carpo-metacarpal articulation of tlie tJiumb. This is a capsular ligament. In this joint are found all the movements except axial rotation. Name the ligaments of the four inner carpo-metacarpal articulations. They are dorsal, palmar, and interosseous. How are these joints supplied witJi nerves / By the ulnar median and posterior interosseous. How many intcrmetacarpal articulations are t lie re f Four ; bound together by dorsal, palmar, and interosseous ligaments. How are the heads of the metacarpal bones held together ? By transverse ligaments. In front of these ligaments pass the lumbrical muscles, with the digital vessels and nerves ; behind, pass the interossei muscles. Here are seen the reflected tendon of the rectus and the triangular ' ilio-tro- ohanterio' band Ischio-femoral band This is placed ou the weak portion of the capsule FIG. 307. POSTERIOR VIEW OK THE CAPSULE OK THE HII--JOINT. The metacarpo-pJialangeal articulations are jive in number. Class, diarthrosis ; subdivision, condylarthrosis. The ligaments are lateral and glenoid. The nerves and arteries come from the digital branches. Classify the intcrplialangcal articulations. They belong to the class diarthrosis ; subdivision, ginglymus. The proper ligaments are lateral and glenoid. Dorsally, the tendon of the extensor com- munis digitorum acts ligamentously ; on the palmar surface, the tendons of the flexors. The articular arteries and nerves come, according to the rule, from the vessels and nerves that supply the muscles that move these joints. THE HIP-JOINT. 1. Class. Diarthrosis ; axial rotation and four angular movements. 2. Subdivision. Knarthrosis or ball-and-socket. ARTICULA TIONS. LIGAMENTS. 439 3. Technical Name. Femoro-acetabular. 4. Osteological Units. Femur and os innominatum. 5. Subdivisional Parts. Ilium, ischium, pubes, and femoral head. 6. Articular Surfaces. Named according to the rule. 7. Basis. A capsule lined by synovial membrane. 8. Local Subdivisions. Ilio-femoral, ischio-femoral, pectineo-femoral. 9. Strengthening' Bands. Tendino-trochanteric band. 10. Incorporated Tendon of the Pectineus Muscle (ligamentum teres). 1 1. Bony Limitations. The brim and circumference of acetabulum. 12. Nerve-supply. Anterior crural, obturator, great sciatic, sacral plexus. 13. Blood-supply. Obturator, circumflex, gluteal and sciatic arteries. 14. Ligamentous Muscles. (i) Sartorius ; (2) rectus femoris ; (3) ilio-psoas ; Tendon of rectus pulled up Tendino-trochanteric band passing between rectus and vastus externus Placed on the weak spot of capsule, which is sometimes perforated to allow the bursa under psoas to com- municate with joint Ilio-femoral band Pectineo-femoral band FIG. 308. ANTERIOR VIEW OK THE CAPSULE OK THE HIP-JOINT. (4) pectineus ; (5) gracilis ; (6) adductors longus, brevis, and magnus ; (7) the glutei maximus, medius, and minimus ; (8) the obturators internus and ex- ternus ; (9) the gemelli, superior and inferior; (10) the tensor vaginae femoris ; (i i)'the semitendinosus, biceps, and semimembranosus. Name the ligaments of the hip. (i) The capsular ligament, the basis of the joint ; (2) the transverse ligament ; (3) the ligamentum teres, an interarticular structure ; (4) the cotyloid, a circum- ferential cartilage. What can you say of the capsular ligament / It is one of the strongest ligaments in the body. It is attached to the an- terior intertrochanteric line in front ; posteriorly, it is attached to the back of the neck, one-half of an inch above the posterior intertrochanteric line. 440 PRACTICAL ANATOMY. What can yon say of the ilio-femoml band / This is the strongest band. Its apex is attached below the anterior inferior iliac spine ; its base is attached to the anterior intertrochanteric line. Describe t/ic ligamentum teres. Externally, it is attached to the lips of the cotyloid notch ; between these extremes, fibres spring from the transverse ligament. Internally, the ligament is attached to the depression in the head of the femur called the tereal. Name all the bony parts about the hip-joint. (Fig. 226.) The greater and lesser trochanters, the neck of the femur, the anterior and posterior intertrochanteric lines, the anterior inferior spinous process of the ilium, the ilio-pubal eminence and line, the tuber of the ischium, the ischio-pubic ramus. THE KNEE-JOINT. 1. Class. Diarthrosis, because of free movement and constant synovia. 2. Subdivision. Ginglyinus, because of motion in two directions. 3. Technical Name. Tibio-femoral articulation. 4. Osteological Units. Femur, tibia, and patella. 5. Subdivisional Parts. Femoral condyles, tibial tuberosities. 6. Articular Surfaces. Named according to general rule. 7. Basis. A capsule lined by synovial membrane. 8. Local Subdivisions. Internal, external, anterior, posterior. 9. Strengthening Bands. Biceps, sartorius, semimembranosus. 10. Incorporated Tendons. Peroneus longus, adductor magnus. 1 1. Bony Limitations. Patella, tibia, and femur. 12. Nerve-supply. Great sciatic, anterior crural, obturator. 13. Blood-supply. Articular arteries from the internal and external articular branches of the popliteal artery, both above and below the joint ; from the azygos ; from the recurrent branches of both the anterior and posterior tibial arteries ; from the anastomotica femoris. 14. Ligamentous Muscles. (i) Extensor quadriceps femoris ; (2) gracilis and sartorius ; (3) semitendinosus and semimembranosus and biceps ; (4) gastroc- nemius and plantaris. Name all tJic ligaments of the knee-joint. (i) The fibrous expansion of the extensors (strengthening bands) ; (2) cap- sular or anterior ligament ; (3) posterior ligament or ligament of Wins- low ; (4) external lateral ligament ; (5) internal lateral ligament ; (6) ligamentum patellae ; (7) anterior crucial ligament ; (8) posterior crucial ligament ; (9) internal semilunar fibro-cartilages ; (10) external semilunar fibro-cartila^es ; (i i) the coronaiy ligament ; (12) the transverse ligament. / 1 'liat is the ligamcntnni patella' / It is a strong tendon by which the extensors of the leg are inserted into the tubercle of the tibia. Its borders form a guide to the surgeon in injecting and aspirating the cavity of the synovial membrane at the knee. Behind the ten- don, between this and the true capsule, is a mass of fat and a small bursa, re st- ing on the bursal segment of the tubercle of the tibia. In front of the liga- mentum patella- is a large prepatellar bursa, whose enlargement is known as "housemaid's knee." Laterally, the ligamentum patella- is continuous with the fibrous expansion of the extensor muscles of the leg. Describe and locate tJic ligament of Winslo-^<. It bridges the space between the internal and external lateral ligaments. It has perforations for vessels and nerves. It is strengthened by an aponeurosis of the semimembranosus muscle. It forms part of tin- floor of the popliteal space. On it rest the popliteal vessels. lagamentum teres Capsular ligament Capaular ligament, cut tyloid ligament Capsular ligament FIG. 309. HIP-JOINT AFTER DIVIDING THE CAPSULAR LIGAMENT AND DISARTICULATING THE FEMUR. Aperture leading into the bursa beneath the quadri- ceps extensor Attachment of capsular, or anterior ligament to femur Fatty tissue within cut edge of ligamentum mucosum Anterior crucial ligament External semilunar nbro-cartilage Coronary ligament Posterior crucial ligament Internal semilunar nbro-cartilage Transverse ligament Coronary ligament FIG. 310. ANTERIOR VIEW OF THE INTERNAL LIGAMENTS OF THE KNEE-JOINT. 2 9 441 442 PRACTICAL ANATOMY. Describe tlic location, length, and relations of tlic infernal la feral ligament. It extends from the inner condyle to the tibia, being about three inches in length. Its outer surface is related to the gracilis, the semimembranosus, and the sartorius muscles ; its deep surface is in relation with the coronary ligament and Flantaris Outer head of gastrocnemius External lateral ligament: anterior portion Posterior part of external lateral ligament Tendon of popliteus Tendon of biceps Posterior superior tibio- nbular ligament Tendon of adductor magnus Inner head of gastrociiemius Tendon of semi-membra- noauB with its slip to thicken the posterior liga- ment Internal lateral ligament Kit;. 311. POSTERIOR VIEW OK THE KNEE-JOINT. Ligamentum patellae Transverse ligament Anterior crucial Internal semilunar flbro- cartilage Posterior crucial ligament Expansion from quadriceps extensor tendon t~ External semilunar flbro- \ \ cartilage Tendon of biceps External lateral ligament In.. 312. STRUCTURES I.YIM; ON mi Hi \i> <>! IHI TMIIA. (Right knee.) semilunar cartilage. This ligament is the divorced Undon of the adductor magnus muscle. /'lie external lateral ligament Consists of hoi,' many parts / Of two an anterior and a posterior. (I'"ig. 31 I.) The anterior, the longer. A R TICULA TIONS. LIGAMENTS. 443 extends from the tubercle on the outer femoral condyle to the head of the fibula. Beneath this ligament is the popliteus tendon in its synovial sheath. The posterior portion is inserted into the styloid. It binds the popliteus to the outer tuberosity. Describe tlie anterior or capsular ligament proper. It is thin, and attached to the synovial membrane. It is attached to the femur, patella, popliteus muscle, and internal lateral ligament. Locate and give function of the semilunar fibro-cartilages, and mention other members of the same physiological class of ligaments. They are two circumferential cartilages resting on the articular facets of the tibia. In mechanics they correspond to a ball-bearing. They deepen the cavity which they surround. The cotyloid of the hip, the glenoids of the shoulder Posterior crucial lagamentum mucosuin Alar ligament Alar ligament Synovial pouch under tendon of quadriceps extensor FIG. 313. ANTERIOR VIEW OF THE KNEE-JOINT, SHOWING THE SYNOVIAL LIGAMENTS. (Anterior portion of capsule with the extensor tendon thrown downward.) and of the interphalangeal and metacarpo-phalangeal articulations belong to the same class. Name the attachments of the semilunars. (Fig. 312.) They are attached loosely to the borders of the tuberosities by the coronary ligament ; to each other, in front, by the transverse ligament ; their extremities are attached to the depressions in front and behind the spine of the tibia. (Fig. 312.) What can yon say of the synovia! membrane of the knee-joint f It is the largest in the body. One part forms a sac beneath the patella ; another extends some distance above the attachment of the capsule above the joint ; it covers all the surface of the crucial ligaments except at two parts. Give the origin and insertion of the crucial ligaments. (Fig. 312.) The anterior crucial is attached to the tibia in front of the spine, and to the 444 PRACTICAL ANATOMY. border of the inner facet, and to the inner and back part of the outer condyle. The posterior is attached to the popliteal notch and adjacent structures, and to the outer part of the inner condyle. (Fig. 227.) Give synonyms for the crucial ligaments. The anterior is called also external ; the posterior is called also internal. Define ligaincnta a/aria and ligamentuui inucosum. The terms are misnomers. These structures are parts only of the synovial membrane. (See Fig. 313.) NOTE. The student should endeavor to make his dissection resemble the cuts, and then exercise his knowledge of osteology by minutely describing all the attachments and relations. Drill of this kind will make him familiar with the text, as well as with the cadaver, and be splendid discipline in cultivating descriptive powers a faculty each one possesses to greater or lesser degree. Name, locate, and define the varieties of synovial membrane. 1. The articular, which is found in all freely movable joints, as the knee and hip. In the foetus it is said this membrane covers the articular surfaces of the cartilage, as well as the interior of the capsule. 2. The bursal varieties are of two kinds. Mucous bursae are found between the skin and bone, as the prepatellar. Synovial bursae are found between tendons and bone, as about the knee between the ligamentum patellae. 3. The vaginal kind. This variety will be found surrounding the flexor tendons of the digits, in the hand and foot ; surrounding the long tendon of the biceps in the bicipital canal of the humerus under the transverse ligament of this bone. THE TIBIO-FIBULAR UNION. 1. The superior tibio-fibular articulation has a capsule, an anterior and a posterior tibio-fibular ligament. It belongs to the class diarthrosis, because of its constant capsule and syno- via, and to the subdivision arthrodia, because of its gliding movement. The synovial cavity of this joint may communicate with the knee. The blood-supply comes from the external articular and recurrent tibial. The nerve-supply is from the recurrent branch of the external popliteal and the inferior external articular. 2. The tibio-fibular interosseous membrane is incomplete above for about an inch. The anterior tibial artery passes through here, between the two heads of the tibialis posticus muscle, to the anterior part of the leg. The function of membrane is principally for muscular origin. It has two borders the tibial and the fibular ; two surfaces the anterior and the posterior. The anterior is in relation with the anterior tibial nerve and vessels and with the muscles of the anterior region of the leg. The posterior surface is in relation with the tibialis posticus and the flexor longus hallucis. 3. The inferior tibio-fibular articulation. (Fig. 317.) Class. Diarthrosis, because of free movement and synovia. Subdivision. Arthrodia, because of a gliding movement. The ligtiincnts arc anterior, posterior, transverse, and inferior interosseous, all of which are easily found. The synovial membrane is continuous with that of the ankle-joint. The nerve-supply is from the internal or long saphenous, ante- rior and posterior tibial. The blood-supply is from the peroneal and its ante- rior branch. THE ANKLE-JOINT. 1. (.'/(iss. Diarthrosis, because of a capsule and free movement. 2. Subdivision. (linglymus, because of movement in two directions. . / A' T1CULA TIONS. LIGAMENTS. 445 3. Technical Name. Tibio-fibulo-astragaloid articulation. 4. Osteological Units. Tibia, fibula, and astragalus. 5. Snbdivisional Parts. Inner and outer malleoli, astragalus. 6. Articular Surfaces. Named according to the general rule. 7. Basis. A capsule lined by a secreting synovial membrane. 8. Local Subdivisions. Anterior, posterior, internal, external. 9. Strengthening Bands. None. 10. Incorporated Tendons of Obsolete Muscles. None. 1 1. Bony Limitations. Malleoli of tibia and fibula, and the os calcis. 1 2. Nerve-supply. Anterior and posterior tibial, and internal saphenous. 13. Blood-supply. Anterior and posterior tibial and peroneal arteries. 14. Ligamentous Muscles. Tibialis anticus, extensor proprius hallucis, ex- tensor communis digitorum, peroneus tertius, peroneus longus, peroneus brevis, tibialis posticus, flexor longus digitorum, flexor longus hallucis, and the three muscles inserted by the tendo Achillis. Give the attachments of the anterior ligament of the ankle-joint. (Fig. 317.) It is attached above to the malleoli of the tibia and fibula, to the tibia, and to the anterior inferior tibio-fibular ligament ; below, it is attached to the neck of the astragalus. Give the relations of the anterior ligament of the ankle-joint. Anteriorly, it is in relation with the anterior tibial nerve and vessels, and all the muscles of the front of the leg ; posteriorly, with the synovial membrane and a fatty mass of connective tissue. Give the attachments of the posterior ligament of the ankle-joint. (Fig. 317.) It is attached above to the external malleolus, the tibia, and the posterior in- ferior tibio-fibular ligament ; below, to the posterior surface of the astragalus. Describe the internal lateral ligament. (Fig. 318.) It is called the deltoid ligament. It is attached above to the lower border of the internal malleolus ; below, to the astragalus, the sustentaculum tali, and the calcaneo-astragaloid ligament. Externally, this ligament is in relation with the tibialis posticus and flexor longus digitorum muscles ; internally, with the synovial membrane. Describe the external ligament of the ankle-joint. (Fig. 317.) It has three fasciculi, or bundles, two of which are horizontal and one ver- tical. The anterior bundle extends from the fibular malleolus to the astragalus in front ; the posterior bundle from the malleolus to the posterior surface of the astragalus ; the middle bundle from the malleolus to the outer surface of the os calcis. Give the relations of the external ligament of the ankle-joint. Externally, with the tendons of the peroneus longus and peroneus brevis muscles ; internally, with the synovial membrane. Describe the movements in tJic ankle-joint. This joint is a hinge ; hence it has movement in two directions, as in ordinary walking. If, however, you extend the foot fully, you will find considerable lateral motion. Flex the foot to the fullest extent, and no lateral motion is pos- sible. Study the diameters of the articular part of the astragalus, and also the diameters of the intermalleolar slot, in which the astragalus works, and you will see reason for free lateral mobility of the foot in extreme extension, in the differ- ence in these diameters. What can you say of the synovial membrane of the ankle-joint .' It lines the ligaments, and is said by Morris to secrete more synovia than any other synovial membrane. 446 PRACTICAL ANATOMY. THE TARSUS TARSAL ARTICULATIONS. Define tlic i^ord tarsus, and name its Jwnwlogue in the upper extremity. The word means instep ; its homologue is the carpus, which means wrist. POSTERO-INFERIOR SURFACE OF THE CALCANEUM Abductor minimi digit! Abductor oasis metatarsi quinti Accesaoriua (outer head) Flexor brevis halluci Abductor ossis metatarsi quinti Flexor brevis minimi digit! Adductor hallucis Third plantar iuterosseous Second plantar interosseous First plantar interosseous Flexor brevis minimi digit! Abductor brevis minimi digiti Third plantar interosseous Second plantar interosseous First plantar interosseous Flexor brevis digitorum Flexor loiiguu digitorum Abductor halluois Flexor brevis digitorum Accessorius i inner head) Tibialis posticus Tibialis anticua Peroneus lonRU Abductor hallucis Flexor brevia halluoit (inner portion) Flexor brevis hallucis (outer portion) Adductor hnllnois Trausversus pedis Flexor longus hallucii l-ii.. 314. Till, I.ii i FOOT. (I'lantar surface. ) (Study tlic insertion and location of tendons on tliis and compare your dissection therewith.) To ?c /tut class do tlic tar sal hones belong .' To icliat is their shape adapted / They are classified as short bones ; tlu-ir function is to combine gre strength with slight motion. ARTICULA TIONS. LIGAMENTS. 447 Xante the bones of the tarsus and indieate tltcir fanciful derivation. (i) Astragalus, the dice bone; (2) calcaneum, the heel bone; (3) scaphoid, Tendo Acliillis Extensor brevis digitorum Extensor longus halluoia Extensor brevis digitorum Peroneus brevis Peroneus tertius METATARSUS FIRST PHALANX SECOND PHALANX THIRD PHALANX Extensor longus digitorum Fu;. 315. THE LEFT FOOT. (Dorsal surface.) (Study origin and insertion of muscles on this figure and compare with your dissection.") resembling a boat; (4) cuboid, like a cube; (5) cuneiform, like a wedge. The ancient shepherds threw dice. The bones they used were from the sheep, hence our name, astragalus, or dice bone. 448 PRACTICAL ANATOMY. Describe tJie astragalus. (Fig. 315.) This bone has (i) a head, which articulates with the scaphoid bone ; (2) a neck, by which the head is joined to the body of the bone ; (3) a body, which has superior, inferior, internal, external, and posterior surfaces. Give the importance of each surface of the astragalus. (i) The superior surface articulates with the tibia ; (2) the external surface articulates with the fibular malleolus ; (3) the internal surface articulates with the tibial malleolus; (4) the inferior surface articulates with the calcaneum ; (5) the posterior surface has a groove for the flexor longus hallucis. Describe the calcaneum or Jic el-bone. (Fig. 315.) This bone has six surfaces anterior, posterior, superior, inferior, internal, and external. Give the importance of each surface. (i) The anterior surface articulates with the cuboid bone ; (2) the posterior surface has the tendo Achillis attached to it ; (3) the external surface has two peroneal grooves and a tubercle between them ; (4) the internal surface has the FIG. 316. SECTION TO SHOW TMK SYNOVIAI. CAVITIES OK THK FOOT. i. Posterior calcaneo-astragaloid. 4. Tarsal. 2. Calcaneo-cuboid. 5. Cubo-metatarsal. 3. Anterior calcaneo-astragalo-scaplioid. 6. First inetatarso-cuneiform. sustentaculum tali and a groove ; (5) the inferior surface has the three important tubercles ; (6) the superior surface has an astragaloid articular surface. Name and give importance of the tubercles of tlie calcaneum. (Fig. 314.) (i) The inner tubercle gives origin to the abductor hallucis, the flexor brevis digitorum, and the abductor minimi digiti ; (2) the outer tubercle gives origin to the abductor minimi digiti, and to the inconstant abductor ossis metatarsi quinti ; (3) the anterior tubercle gives attachment to the short plantar or cal- caneo-cuboid ligament. Describe the scaphoid bone. (Fig. 316.) This bone articulates posteriorly with the head of the astragalus ; anteriorly with the three cuneiform bones. The superior, inferior, and external surfaces art- rough, for the attachment of ligaments. The internal surface has the tuberosity, into which is inserted the tibialis posticus muscle. Describe the cuboid bone. (Fig. 316.) It has six surfaces : (i) The anterior articulates with the bases of the fourth and fifth tnrtatarsals ; (j)the posterior articulates with the calcaneum; (3) tin- internal articulates with the scaphoid (sometimes) and external cuneiform ; (4) the superior is rough, for attachment of ligaments ; (5) the inferior has a groove ARTICULA TIONS. LIGAMENTS. 449 for the peroneus longus ; (6) the outer is almost negative, and is continuous with the inferior surface. Can you say anything more about the inferior surface of tJic cuboid bone f Yes ; it has a ridge behind the peroneal groove, for the attachment of the long calcaneo-cuboid ligament ; this ridge terminates externally in the sesamoid articular surface, which articulates with the peroneal sesamoid bone, in the tendon of the peroneus longus. The flexor brevis hallucis also derives its origin on this surface of the bone. (Fig. 314.) Describe t/ie surfaces of the internal cuneiform. (i) The internal surface has the insertion of the tibialis anticus ; (2) the exter- nal articulates with the second metatarsal and middle cuneiform ; (3) the anterior Antero-inferior tibio-flbular ligament Anterior ligament of ankle-joint Outer extremity of the mterosseous ligament External calcaneo- scaphoid ligament Postero-inferior tibio- flbular ligament Fasciculus of posterior ligament of ankle Posterior fasciculus of external lateral ligament ligament Internal calcaneo-cuboid Dorsal External Middle fasciculus of external lateral alcaneo- calcaneo- ligament of the ankle cuboid astragaloid ligament FIG. 317. EXTERNAL VIEW OF THE LIGAMENTS OF THE FOOT AND ANKLE. articulates with the first metatarsal bone ; (4) the posterior articulates with the scaphoid bone ; (5) the inferior has the insertion of the tibialis posticus. Describe the surfaces of the middle cuneiform. (i) The anterior articulates with the second metatarsal bone ; (2) the posterior articulates with the scaphoid bone ; (3) the internal articulates with the internal cuneiform bone ; (4) the external articulates with the external cuneiform bone ; (5) the superior surface is rough, for ligamentous attachment; (6) into the in- ferior surface is inserted the tibialis posticus muscle and ligaments. Describe the surfaces of the external cuneiform. (i) The anterior articulates with the third metatarsal ; (2) the posterior with the scaphoid bone ; (3) the internal with the middle cuneiform bone ; (4) the external with the fourth metatarsal and cuboid bone ; (5) the inferior is for tibialis posticus and ligaments ; (6) the superior is for ligamentous attachment. Internal lateral ligament Inferior cal- ooneo-scaphoid ligament Short plantar ligament Long plantar ligament FIG. 318. INNER VIEW OK THE ANKLK AND THE TARSUS, SHOWING THE GROOVE FOR THE TENDON OF THE TIBIAI.IS POSTICUS. Long plantar or long Inferior calcaneo-cuboid ligament Tendon of peroneus longus GROOVE FOR FLEXOR LONGUS HALLUCIS Inferior caloaneo-acaphoid ligament Short plantar or short interior calcaneo-cuboid ligament TUBERCLE OF SCAPHOID INTERNAL CUNEIFORM Insertion of peroueus longus 1'IC. 319. Lll.AMIM^ 01 IHI Soil (,| Tin.; I.KI I 450 AR T1CULA TWNS. L IGAMENTS. 45 1 Give comparative size of the cuneiform bones. The internal cuneiform is the largest bone ; the middle cuneiform is the smallest bone ; the external cuneiform is intermediate in size. Name the principal muscular-traction points in and about the tarsus, and indi- cate the muscle attached thereto. (i) Calcaneum for the tendo Achillis ; (2) calcaneum for the abductor hallucis and flexor brevis digitorum ; (3) calcaneum for the abductor minimi digiti and accessorius ; (4) calcaneum for the extensor brevis digitorum ; (5) sustentaculum tali groove for the tendon of flexor longus hallucis ; (6) the tuberosity of the scaphoid bone for the tibialis posticus ; (7) the internal cuneiform for the tibialis anticus ; (8) the first metacarpal for the peroneus tertius and tibialis anticus ; (9) the fifth metatarsal for the peroneus brevis ; (10) cuboidal groove for the ten- don of peroneus longus. Locate the medio-tarsal articulation by limitation, and name its ligaments. This joint is limited posteriorly by the calcaneum and astragalus ; anteriorly, by the scaphoid and cuboid. (Fig. 316.) The ligaments are : (i) The external calcaneo-scaphoid ; (2) the inferior calcaneo-scaphoid ; (3) the astragalo-scaphoid ligament ; (4) the internal or interosseous calcaneo-cuboid ligament ; (5) the long inferior calcaneo-cuboid ligament; (6) the short inferior calcaneo-cuboid liga- ment ; (7) the dorsal calcaneo-cuboid ligament. Give the attachments of the long inferior calcaneo-cuboid ligament and the common name for the same. (Fig. 319.) It is also called the long plantar ligament. It is attached to the whole infe- rior surface of the calcaneum behind ; to the cuboid and bases of the meta- tarsals in front. Can yon mention any other important fact in regard to the long plantar ligament / Yes ; it completes the canal for the peroneus longus muscle, and also gives origin to the adductor hallucis and the flexor brevis minimi digiti. (Fig. 319.) Give the attachments of the short inferior calcaneo-cuboid ligament and its common name. It is called the short plantar ligament. It is attached to the under surfaces of the calcaneum and cuboid. (Fig. 319.) From what source does the medio-tarsal joint receive its nerve-supply ? From the outer division of the anterior tibial, the musculo-cutaneous, and the external plantar nerves. From ivhat source does the medio-tarsal joint receive its blood-supply ? From the anterior tibial, the dorsalis pedis, and the internal and external plantar arteries. What class and subdivision does the medio-tarsal articidation belong in ? (i) The astragalo-scaphoid joint is diarthrosis by class, and enarthrodia by subdivision ; (2) the calcaneo-cuboid is diarthrosis by class, and saddle arthrodia by subdivision. Name the ligaments of the calcanco-astragaloid articulation. (i) The external calcaneo-astragaloid ligament; (2) the internal calcaneo- astragaloid ligament ; (3) the posterior calcaneo-astragaloid ligament ; (4) the interosseous calcaneo-astragaloid ligament. Locate the interosseous ligament. It extends from the calcaneum to the astragalus, connecting the parallel oblique grooves of these two bones. Describe the scapho-cuneiform articulation. Class. Diarthrosis, because of free movement and a capsule. Subdivision. Arthrodia, because of a gliding movement. Ligaments. Dorsal, plantar, and internal. 452 PRACTICAL ANATOMY. Describe the intercuneiform articulations. Class. Diarthrosis, because of free movement and a capsule. Subdivision. Arthrodia, because of a gliding movement. Ligaments. Dorsal, plantar, and interosseous. Blood-supply. Metatarsal and plantar arteries. Nerve-supply. Anterior tibial and plantar nerves. Describe the tarsometatarsal articulations. Class. Diarthrosis, because of free movement and a capsule. Subdivision. Arthrodia, because of a gliding movement. Ligaments. Dorsal, palmar, and interosseous. Nerve-supply. Anterior tibial and plantar nerves. Posterior ligament of ankle- joint Posterior part of the internal lateral ligament The lower part of the inter- oaseous membrane Transverse ligament of inferior tibio-nbular joint Posterior fasciculus of external lateral ligament Middle fasciculus of external lateral ligament FlG. 320. LUIAMENTS SEEN FROM THE BACK OF THE ANKLE-JOINT. Describe the intermetatarsal articulations. Class. Diarthrosis, because of free movement and a capsule. Subdivision. Arthrodia, because of a gliding movement. Ligaments, Dorsal, plantar, and interosseous. //ow arc the heads of the nictatarsal bones connected / By rather strong, short, transverse ligaments. Describe the metatarso-phalangeal articulations. ( '/tiss. Diarthrosis, because of free movement and a capsule. Subdivision. Condylarthrosis, because of no axial rotation. Ligaments. Lateral, dorsal, plantar, sesamoul. Liganicntons Muscles. Flexors and extensors of the digits. Describe the interphalangeal articulations. Class. Diarthrosis. because of free movrnu-nt. Subdivision. (iinglymus, because of motion in two directions. ARTICULA TIONS. LIGAMENTS. Ligaments. Laterals, dorsals, and glenoids. Ligamentous Muscles. Flexors and extensors of the digits. Nerve-supply. Internal and external plantar nerves. 453 FIG. 321. RIGHT INNOMINATE BONE, EXTERNAL ASPECT. Superior border, or crest. 2. Anterior superior iliac spine. 3. Posterior superior iliac spine. 4,4,4. Superior curved line. 5,5- Inferior curved line. 6. Surface between inferior curved line and acetabulum. 7. Anterior inferior iliac spine. 8. Anterior interspinous notch. 9. Posterior inferior iliac spine. 10. Posterior interspinous notch. II. Spine of ischium. 12. Great sacro-sciatic notch. 13. Acetabulum. 14. Fundus of acetabulum. 15,15. Circumference of acetabulum. 16. Cotyloid notch. 17. Spine of pubes. 18. Horizontal branch of pubes. 19. Descending branch of pubes. 20,20. Ischium. 21. Groove for tendon of obturator externus muscle. 22. Obturator foramen. P. LAC. it E.SAL. FIG. 322. PELVIS, ANTEKO SUPKKIOR VIEW, SUPERIOR STRAIT. 1,1. Internal iliac fossae. 2,2. Iliac crests. 3,3- Anterior superior iliac spines. 4,4. Anterior inferior iliac spines. 5,5. Ilio-pectineal eminences. 6,6. Horizontal branches of pubes. 7.7. Bodies and symphysis of pubes. 8, 8. Acetabula. 9, 9. Tuberosities of iscbia. 10, 10. Ascending rami of ischium. II, II. Descending rami of pubes. 12, 12. Spines of ischia. 13, 13 Posterior wall of pelvic cavity. 14, 14. Sacro-iliac symphyses. 15. Sacro-vertebral angle. 16, 16. Superior strait. THE PELVIS ITS ARTICULATIONS AND LIGAMENTS. The bones of the pelvis are the sacrum, coccyx, and ossa innominata. The pelvis articulates with the lumbar part of the vertebral column, and with the head of the femur. We m;iy then classify the articulations, for purposes of con- venience, as (i) intrinsic, where the articulation is between pelvic bones ; (2) ex- trinsic, where the articulation is between pelvic bones and bones not pelvic. PRACTICAL ANATOMY. The intrinsic pelvic articulations arc : (i) The sacro-iliac, between the sacrum and ilium ; (2) the sacro-sciatic, between the sacrum and ischium ; (3) the interpubic, between the pubic bones ; (4) the sacro-coccygeal, between the sacrum and coccyx. The extrinsic ligaments are : (i) The sacro-lumbar, between the sacrum and the last vertebra of the lum- bar region ; (2) the femoro-innominate group of ligaments. Name tlie ostcological points of interest in and about the pelvis. (i) Symphysis pubis, between the pubic bones; (2) pubic crest, limited by the angle and spine of pubis ; (3) ilio-pubic line, limited by the spine and ilio- pubic eminence ; (4) the ilio-pubic eminence, at the junction of pubis and ilium ; FIG. 323. FEMUR, POSTERIOR ASPECT. 1,1. Linea aspera. 2,2. External division. 3. Internal division. 4,4. Inferior divisions. 5. Iliad. 6. Depression for attachment of round ligament. 7. Neck. 8. Great trochanter. 9. liigital or trochameric fossa. IO. Lesser trochanter. II. Outer coiulyle. 12. Inner condyle. 13. Inter condyloid notch. 14. Outer tuberosity. 15. Inner tuberosity. (5) the iliac crest, limited by the superior iliac spines, anterior and posterior; (6) the acetabulum, at the junction of the ilium, ischium, and pubes ; (7) the fossa acetabuli, the non-articular part of the acetabulum ; (8) the cotyloid notch, an interruption in the acetabular brim; (9) the lesser sacro-sciatic notch, between the ischial tuber and spine ; (10) the ischial spine, between the greater and les.ser sciatic notches ; (i i) the tub'er of the ischium, one of the grand divisions of the ischium ; (12) the ischio-pubic ramus, between the pubes and ischium ; (13) the obturator foramen, bounded by the pubes and ischium; (14) the pelvic inlet, between the true and false pelvis ; (15) the subpubic arcade, between tin- ischio- pubic rami ; (16) the anterior superior iliac spine, for the insertion of Poupart's ligament ; (17) the anterior inferior iliac spine, lor the oiigin of the straight head of the reetus; (18) the anterior interspinous notch, between the anterior iliac ARTICULA TIONS. LIGAMENTS. 455 spines ; (19) the posterior iliac spines, superior and inferior ; (20) the promontory of the sacrum ; (21) the alas of the sacrum, consisting of transverse and costal elemental parts ; (22) the anterior sacral foramina, for the anterior sacral nerves ; (23) the sacro-iliac synchondrosis, right and left; (24) the greater and lesser Superior pubio ligament Inferior pubic ligament FIG. 324. ANTERIOR VIEW OF THE SYMPHYSIS Puuis (FEMALE, SHOWING GREATER WIDTH BETWEEN THE BONES). Inferior pubio ligament FIG. 325. POSTERIOR VIEW OF THE SYMPHYSIS PUBIS, SHOWING THE BACKWARD PROJECTION OK THE SYMPHYSIAI. SUBSTANCE AND THE DECUSSATION OF THE FIBRES FROM THE INFERIOR PUBIC LIGAMENT. Superior pubic ligament Inferior pubic ligament FIG. 326. ANTERIOR VIEW OF THE SYMPHYSIS Pi ms (MALE) SHOWING DECUSSATION OF THK FIBRES OF THE ANTERIOR LIGAMENT. trochanters of the femur ; (25) the anterior and posterior intertrochanteric lines ; (26) the digital or trochanteric fossa ; (27) the superior and inferior cervical tubercles of the femur. 45 6 PRACTICAL ANATOMY. Symphysis Pubis : Class. Amphiarthrosis, because of union by cartilage and slight motion. Ostcological lUements. The bodies of the two pubic bones. Ligaments. Anterior, posterior, superior, inferior, and interosseous cartilage. Is there any difference bcticeen this joint in tlic tico sexes? The joint is shorter and broader in the female than in the male. (Fig. 324.) Is the nerve-supply of the sympliy sis pubis ice// understood / No ; but it probably is derived from the ilio-inguinal, ilio-hypogastric, and internal pudic nerves. From ivhat source does this articulation derive its blood-supply / From the internal pudic, the obturator, deep epigastric, internal circumflex, iliac, and external pudic arteries. Foramen for last lumbar nerve Intervertebral body between last lum- bar and first sacral vertebrae Foramen for anterior primary branch of fourth lumbar nerve The ilio-lumbar ligament The sacro-lumbar ligament Superior sacro-iliac ligament Anterior sacro-iliac ligament Great aacro- sciatic ligament Lesser sacro-sciatic ligament Fiu. 327. ANTERIOR VIEW OK 1111. Wlial influence has pregnancy on t/ic interosseous cartilage beticeen the pubic bones ? The cartilage becomes softer and the blood-supply more abundant. Is there any special difference in tlic hiterosseons cartilage in /lie male and female f It is thicker in the female than in the male. \Vliat is sympliysotomy or sympliysiotomy .' Cutting through the pubic symphysis to increase tin- conjugate diameters of the pelvic canal. In this obstetric operation all the ligaments of the symphysis pubis are cut. Sacro-iliac Articulation and Its Ligaments : Class. AmphiarthroMs, bones united by cartilage and slight motion. ARTICULATIONS. LIGAMENTS. 457 Osteological Units. The sacrum and ilium. Snbdii'isional Parts. Auricular surfaces of the sacrum and ilium. Nerve-supply. Superior gluteal, sacral plexus, first and second sacral nerves. Blood-supply. Gluteal, ilio-lumbar, and lateral sacral arteries. Morphologically, what is that fart of the sacrum that articulates with the auricular part of the ilium / It is the result of a peculiar modification of the costal elements of the first three sacral vertebrae. Name and locate the ligaments of this articulation. (i) Anterior sacro-iliac, from pelvic brim to greater sacro-sciatic foramen ; (2) posterior sacro-iliac, from back of sacrum to iliac crest ; (3) superior sacro- iliac, from sacral base to iliac fossa ; (4) inferior sacro-iliac, from sacrum to pos- terior iliac spine ; (5) interosseous ligament is between the two spines. The function of the sacro-iliac ligaments is to bind the sacrum to the ilium. Falciform process of the great ligament . Tendon of biceps muscle, continuous with the great sacro-sciatic ligament FIG. 328. SACRO-SCIATIC LIGAMENTS. (Posterior view. ) They are purely of periosteal derivation. The plate of cartilage between the bones may become ossified, just as the ligaments of the vertebral column some- times do. Occasionally, a distinct synovial cavity is found in the center of this cartilage. Sacro-ischiatic Ligaments : Hozv many ligaments unite the sacrum and ischium ? (Fig. 328.) Two ; the common name for these is sacro-sciatic, which is a contraction of the true word for purposes of euphony. The common names are : (i) Greater or posterior sacro-sciatic ligament; (2) lesser or anterior sacro-sciatic ligament. Locate the greater ligament. The greater or posterior sacro-sciatic ligament is attached above to the mar- gin of the sacrum and coccyx and to the posterior inferior iliac spine ; below to the inner margin of the tuber of the ischium and ascending ramus of the ischium for about two inches. 3 PRACTICAL ANATOMY. \\liat is the special name for the tu'o inches of t lie greater sacro-sciatic ligament that is prolonged on to the inner margin of the ascending rannts of the iscluum f It is called the falciform ligament. (Fig. 328.) This ligament unites with the obturator fascia to strengthen Alcock's canal, in which canal are located the internal pudic nerve and vessels. What are the functions of the greater sacro-sciatic ligament, exclusive of its special part the falciform ligament / It gives partial origin to the gluteus maximus muscle, and converts the lesser sacro-sciatic notch into a foramen. Name the structures that pass through the lesser sacro-sciatic foramen. (i) The tendon of the obturator muscle and its nerve; (2) the internal pudic nerve and vessels. Locate the lesser sacro-sciatic ligament. The lesser or anterior sacro-sciatic ligament is attached above to the margin Superior saero-iliac ligament Anterior eacro-iliac ligament Inferior saoro-iliac ligament Small sacro-sciatic ligament Great sacro-sciatic ligament Fi<;. 329. VERTICAL ANTKRO-POSTKRIOK SECTION OK Tin: I'KI.VIS. of the sacrum and coccyx ; below, to the spine of the ischium. This ligament converts the greater sacro-sciatic notch into a foramen. Name structures transmitted hy the greater sacro-sciatic foramen. (l) The pyriformis muscle, above which pass out the glutcal nerve ami vessels, and below which muscle pass out the sciatic vessels and nerves, the internal pudic nerve and vessels, and the branch of the sacral plexus that sup- plies the obturator muscle. \arne all (he structures that /cave tlie pelvis through the greater sacro-sciatic foramen, cross (he iscl/ial spine, and reenter the pelvis through the lesser sacro- sciatic foramen. (l) The branch of the sacral plexus to the obturator interims; (2} the internal pudic nerve ; (3) the internal pudic vessels. \\7iat becomes of these structures on reentering the pelvis / A R T1CULA TIONS. LIGAMENTS. 459 They enter Alcock's canal, which is a delamination of the obturator fascia strengthened by the falciform ligament, a special part of the greater sacro-sciatic ligament. 2 2 1 FIG. 330. COCCYX, ANTERIOR ASPECT. I. Base. 2, 2. Cornua. 3. Second coccygeal vertebra. 4. Third coccygeal vertebra. 5. Fourth coc- cygeal vertebra. 6. Fifth coccygeal vertebra. Fie';. 331. VERTEBRAL COLUMN, LATERAL ASPHT. 1-7. Cervical vertebrae. 8-19. Dorsal vertel>ne. 20-24. Lumbar vertebra'. A, A. Spinous processes. B, B. Articular facets of transverse processes of first ten dorsal vertebras. C. Auricular surface of sacrum. I). Foramina in transverse processes of cervical vertebrae. The Sacro-coccygeal Articulation and Ligaments : 1 . Class. Amphiarthrosis, bones united by cartilage. 2. Osteological Units. The sacrum and coccyx. 3. Subdivisio nal Parts. Sacral and coccygeal cornua. 4. Nerve-supply. The fourth, fifth sacral, and coccygeal nerves. 460 PRACTICAL ANATOMY. 5. Blood-supply. Middle sacral and lateral sacral artery. 6. Ligaments. Anterior sacro-coccygeal ligament, on the front of bodies ; posterior sacro-coccygeal ligament, on posterior part of bodies ; supracornual ligament, a prolongation of the supraspinous ligament ; intertransverse ligament, analogous to the intertransverse ligaments of the true vertebrae ; intervertebral substance of jelly-like cartilage. The Sacro- vertebral Articulation and its Ligaments : 1. Class. Amphiarthrosis between the bodies of the vertebrae. 2. Class. Diarthrosis between the articular processes. 3. Subdivision. Arthrodia, because of a gliding movement. 4. Osteological Units. Same as between two vertebrae. 5. Subdivisional Parts. Same as in juxtaposition of vertebras. Lateral expanded portion Median longitudinal band Fic.. 332. POSTERIOR COMMON LIGAMENT OK THE SPINE. (Thoracic region.) (Pedicles cut through, and posterior arches of vertebra removed.) 6. Nerve-supply. Fourth and fifth lumbar and sympathetic. 7. Blood-supply. Lateral sacral, last lumbar, ilio-lumbar. 8. Special Name. Sacro-vertebral angle. 9. Ligaments of Sacro-vertebral Articulation. (i) Prolongation down wan of the ligaments of the vertebral column under the same name. They may be modified to some extent to meet the particular demands of a special region ; for this modification you can account philosophically : growth is the correlative of function. (2) Sacro-lumbar ligament, triangular in shape. (3) Ilio-lumbar liga- ment, triangular in shape. THE VERTEBRAL COLUMN AND ITS Lu; AMEN r>. Of what is the vertebral column composed .' Of thirty-three irregular bones, called vertebra.-. They arc classified as true AR TICULA TIONS. LIGAMENTS. 46 1 and false vertebrae. The false vertebrae, nine in number, five sacral and four coccygeal, make by their fusion the sacrum and coccyx. Name tlie regions of tlie vertebral column and give sonic reasons for a regional subdivision of tJic column. The vertebral regions and the number of bones in each are : (i) Cervical reg'on, containing seven bones ; (2) dorsal or thoracic region, containing twelve boius ; (3) lumbar region, containing five bones ; (4) sacro-coccygeal region, con- taining nine bones. Subdivision of the vertebral column into regions depends on a difference in form of the bones, while this difference in the form depends on the function of the region in which the bones are located ; growth predetermines form, and is the correlative of function. What is tlie natural arrangement of adjacent vertebne to cadi other / They are in juxtaposition that is, one next to another, with parallelism of Portion of ligamen- tum subflavum re- moved to show the articular cavity Iiigamentum subflavum 1/11 ; - 333- LlGAMENTA SUBFLAVA IN THE LUMBAR REGION. homologous parts. Thus, this arrangement among the bones of the vertebral column gives a logical basis for studying the ligaments of the column, since we find : Juxtaposition of bodies ; juxtaposition of pedicles ; juxtaposition of lam- inae ; juxtaposition of articular processes ; juxtaposition of spinous processes ; juxtaposition of transverse processes. Wliat is t/ie function of the bodies or centra, and by u'hat ligaments are they held together .' They give solidity and strength to the column. The ligaments of the bodies or centra are the anterior common, posterior common, and intercentral discs of fibro-cartilage. Their union forms an amphiarthrodial articulation, since bone is united to bone by cartilage with limited motion. Give the function and relations of tlie pedicles. The pedicles support the neural arch. Above and below them are found the intervertebral notches, which are converted into intervertebral foramina when 462 PRACTICAL ANATOMY. the vertebrae are in juxtaposition. (Fig. 335.) These intervertebral foramina transmit the spinal nerves and blood-vessels. Give the function of the lainiiue, name tJieir proper ligaments, and tell wherein these ligaments differ liistologically from all otliers of the vertebral column. CERVICAL VERTEBRA COSTAL PROCESS TRANSVERSE PROCESS COSTO-TRANSVERSE FORAMEN NEURO-CENTRAL SUTURE CERVICAL RIB THORACIC VERTEBRA TRANSVERSE PROCESS COSTO-TRANSVERSE FORAMEN NEURO-CENTRAL SUTURE RIB TRANSVERSE PROCESS LUMBAR RIB NEURO-CENTRAL SUTURE COSTAL PROCESS I'K;. 334. MoKI'IlOLOCY I'l Till'. TKANSVKKSK AND A KTH T I.A K l'R X 'l-l- >. The laminae unite posteriorly to enclose the neural canal. They are bound together by the interlaminar ligaments. These are composed of yellow elastic connective tissue, hence they are called the ligament. i subllava. The term sub- flava means yellowish. AR TICULA 776LV.V. LIGAMEXTS. 463 Give the function of the articular processes and tell illicit kind of joints tlicv form when in juxtaposition. The articular processes, by their union, make the vertebral column a concrete whole, the separate parts of which column move or turn on each other. They form diarthrodial articulations of the arthrodial subdivision. The basis of the joint is a capsule lined by synovial membrane. Give the function of the transverse processes and explain their serial morphology in the four regions of the column. The transverse processes are for the attachment of ligaments, muscles, and either fully developed ribs, or rudimentary ones, called costal elements. The simplest series is in the thoracic region. Here we find a transverse process articu- lating with a rib in such a manner as to leave a space bounded by a rib, transverse process, and pedicle. This space is a vascular opening, and is called a costo- The interspinoua ligament The supraspinoua ligament FIG. 335. THE INTERSPINOUS AND SUPRASPINOUS LIGAMENTS IN THE LUMBAR REGION. transverse space. The extremes of the column show this costo-transverse space : a well-formed vertebral canal in the cervical region ; a mere collection of small foramina in the lumbar region ; a depression transmitting a few small vessels in the sacrum, between the costal and the transverse element of the ala of this bone. (Fig. 334.) In the cervical region the rudimentary rib obtains as the anterior tubercle ; in the thoracic region the costal portion is maximal a rib ; in the lumbar region, the transverse process is suppressed and the costal element is very large ; in the sacral region the costal elements of the first three sacral vertebrae are modified to form the auricular part of the sacrum, for articulation with the ilium. In view of the great importance of the subject of the serial morphology ot the vertebrae in your dissections, I here introduce figure 334, which will illustrate the foregoing, leaving the subject of morphology for the student to read up in Morris. Give the function of the spinons processes and name their ligaments. 4 6 4 PRACTICAL ANATOMY. They are for the attachment of muscles and ligaments. Their ligaments are periosteal, and are named interspinous and supraspinous. (Fig. 335.) What is the ligaincntmn nucluz ? Literally, the ligament of the nape of the neck. This is a septum of con- nective tissue between the muscles of the back of the neck. Its attachments are the external occipital protuberance (Fig. 338) and the spines of the cervical ver- tebrae. It is rudimentary in man impossible of demonstration in practical anatomy, except as a very feeble intermuscular connective tissue ; not being demonstrable even, in my experience, as an intermuscular septum, such as we find between the peronei muscles and those on the front part of the leg. Describe the atlas. This is the first of the cervical series of vertebrae. It consists of an anterior Vertical portion of crucial ligament Central odontoid ligament Lateral odontoid ligaments Transverse portion of crucial ligament Accessory band of atlanto- azoidean capsules Atlanto-azoidean joint Oocipito-cervioal or cervico-basilar ligament Posterior common ligament FIG. 336. VERTICAL TRANSVERSE SECTION OF THE SPINAL COLUMN AND THE OCCIPITAL I>m tin- portal blood by the liver. The bile is stored up in the gall-bladder ; the sugar is stored up as potential energy in the hepatic cells. The portal vein enters the root of tin- liver, between the hepatic artery and the common bile-duct. INDEX. A. Abdominal walls, 225 blood-supply, 233 contents, 246 review, 248 function of, 233 interior view, 235 nerve-supply, 233 Abscess, alveolar, 151 Accelerator of penis, 333 Adjectives, substantive, 21 Alcock's canal, 337 Anatomical root of the lung, 207 Anconeus, 355 Annular ligament, posterior, 348 Ansa hypoglossal nerve-loop, 155 Antagonism, anatomical, 18 law of, 308 Anterior thoracic nerves, 195 Antrum of Highmore, 116 analysis, 116 blood-supply, 117 Fillebrown on, 119 nerve-supply, 117 opening for, 118 Aponeurosis defined, 25 Apoplexy, nose-bleeding in, 114 Apposition, anatomical, 19 Arachnoid membrane, 123 appearance of, 126 Arch, fibrous, of gastrocnemius, 377 of soleus, 378 zygomatic, 28 Arches, fibrous, defined, 25 Arteries, gluteal, 372 laryngeal, superior and inferior, IIO popliteal, 369 posterior tibial, 383 sciatic, 372 Artery, anterior tibial, 310 ascending pharyngeal, 63 brachial, and relations, 196 circumflex, internal, use of, 321 common carotid, 58 dorsalis pedis, 310 external carotid, 59 circumflex, 321 facial, 6 1 branches of, in neck, 6 1 femoral, 316 branches of, 320 inferior thyroid, 66 internal carotid, 59 mammary, 66 maxillary, 88 lingual, 60 occipital, 6l posterior auricular, 63 princeps cervicis, 67 Artery, profunda femoris, 520 subclavian, 64 branches of, 65 superficial femoral, branches of, 321 temporal, 63 superior intercostal, 66 thyroid, 60 suprascapular, 66, 359 vertebral, and branches, 68 Articulations, 421 acromio-clavicular, 429 ankle, 445 atlanto-occipital, 467 carpal, 437 chondro-sternal, 473 coraco-clavicular, 430 costo-central, 471 costo-trans verse, 471 elbow, 432 femoro-acetabular, 439 knee, 440 medio-tarsal, 302 occipito-axoid, 468 pelvis, 453 radio-carpal, 435 *radio-ulnar, inferior, 434 radio-ulnar, superior, 432 sacro-coccygeal, 459 sacro-ischiatic, 457 sacro-vertebral, 460 shoulder, 426 sterno-clavicular, 431 table of, 422 tarsal, 446 temporo-mandibular, 425 tibio-fibular, 444 Arytenoid muscle, 109 Ascending vena cava, 212 Auriculo-temporal nerve, 37 ventricular valves, 218 Axilla, or axillary space, 188, 192 angles and contents of, 193 anterior boundary of, 192 thoracic nerves in, 195 apex of, bony boundaries of, 192 axillary artery and branches in, 196 base of, formation of, 192 circumflex nerve in, 195 contents of, 193 internal boundary of, 193 musculo-cutaneous nerve in, 195 musculo-spiral nerve in, 195 posterior boundary of, 192 subscapular nerves in, 195 systematic dissection of, 193 ulnar nerve in, 195 Axillary artery and vein, 196 space, 188, 192 Azygos uvulae, 98 477 478 INDEX. B. Back, 374 accessorius, 405 arteries of, 398 cervicalis ascendens, 405 complexus muscle of, 394, 405 erector spinaa of, 394, 403 ilio-costalis, 405 latissimus clorsi, 399 levator anguli scapulae, 400 longissimus dorsi, 405 multifidus spinae, 407 nerves of, 397, 409 rhomboid muscles of, 400 rotatores spinae, 407 semispinales dorsi and colli, 396, 407 serratus posticus inferior, 400 superior, 400 seventh layer of muscles of, 407 simple movements of, 395 sixth layer of muscles of, 405 spinalis dorsi, 405 splenius capitis et colli, 400 suboccipital muscles, 409 triangle, 409 superficial fascia of, 394 table of muscles of, 395 trachelo-mastoid, 405 transversalis colli, 405 trapezius, 398 twelfth rib of, 394 vertebral aponeurosis of, 394, 400 Biceps, 185 Bile-duct, 251 Bladder, base of, 338 Blood-supply of the dura mater, 131 Bone : clavicle, inferior surface, 191 superior surface, 188 eminences and depressions of, 17 femur, anterior view, 327 posterior view, 326 . hip-bone, internal surface, 287 posterior view, 325 humerus, anterior view, 184 mandible, inner view, 28 outer view, 28 maxilla, antrum, 118 inner view, 116 outer view, 1 17 metacarpal, fifth, base of, 152 pisiform, importance of, 152 ribs, first and second, 198 sacrum, anterior view, 290 scapula, dorsal surface, 345 skull, norma basilaris, 30 farialis, 29 lateralis, 27 sagittal section, 121 sternum, 199 styloid process of temporal, 87 tibia and fibula, anterior view, 300 posterior view, 301 lurbinated, 113 tympanum, 133 ulna and radius, anterior view, 179 posterior view, 353 unciform, importance of, 152 Brachial artery, 196 and branches, 196 pli'\us, 77 l!ra> lii.. i rph.ilir, 212 Jitat hi<> i.i'lialU, 185, 348 I'.iain, Mood supply of", 135 circle of Willis of, 135 Brain, coverings of, 120 ganglionic arteries of, 136 quiz on blood-supply of, 137 removal of, 125 structures seen on base of, 127 two systems of blood circulation of, 137 Branches of abdominal aorta, 258 Buccinator muscle, 93 C. Calcaneum, posterior surface of, 299 superior surface of, 299 Calvarium, 121 removal of, 125 Capsules, 16 Cardiac plexus, 214 root, 2ii Carotid artery, common, 58 external, 59 internal, 59 cavernous stage of, 131 petrosal stage of, 131 seen on removing the brain, 128 sheath, 58 Carpus and hand, exterior muscles of, 152 osteological points of, 152 Cavernous sinus, 129 Central perineal point, 338 Cephalic vein, 189 Cerebro-spinal fluid, 124 Cervical fascia, deep, 47 scheme of, 48 third layer, 57 plexus, 73 Chondro-sternal articulation, 473 Cinder in eye and pain, 150 Circulation, adult, 218 foetal, 219 Circumflex nerve, 195 quadrangular space, 355 Circumflexus palati, 98 Clavicle, 187 Clavi -pectoral fascia, 191 space, 191 Coccygeus muscle, 290 Compound words, 10 rule for, 10 Compressor narium, 34 Constrictor muscles of pharynx, 99 Cord, spermatic, 307 Coronary artery, 218 Corrugator cutis ani, 331 supercilii, 34 Crico-arytenoideus lateralis muscle, no posticus muscle, no Crico-thyroid muscle, no Crura penis, 331 Crus penis, dissection of, 331 D. Deep cervical fascia, second layer, 53 upper attachments and special names for, 51 crural arch, 236 epigastric vessels, 236 Deltoid aponcurosi-. i muscle, 189 Depressor agents of the lower jaw, 93 anguli oris, 32 laliii inferiori-i, 32 INDEX. 479 Depressor muscles of hyoid bone, 55 Dermal muscles, aural, 41 grouped, 41 Descending vena cava, 212 Diaphragm, 285 Diaphragms sellse, 121 Digastric muscle, 63 Dilator naris, anterior, 34 posterior, 35 Dissecting defined, 19 Dr. Loring's case reported, 161 Duct, nasal, 140 Stenson's, 31 Ductus arteriosus, 211 Duodenum, dissection, 252 Dura mater, 121 arteries of, 123 nerves of, 123 sinuses of, 122 E. Emissary structures, tabulated list of, 151 Eustachian tube, 102 muscles attached to, 103 External oblique muscle, 230 F. Face, osteological points of, 29 Facial anastomotic blood areas, 42 artery, 38 nerve, 30 communication of, on the face, 37 dissection of, 36 divisions and branches, 37 escape of, 43 not the cause of toothache, 43 Falx cerebelli, 122 cerebri, 122 dissection of, 126 Fascia, 22 cribriform, 309 cubital, 24 deep, 23 associated with muscles, 24 attachments of, 308 forming intermuscular septa, 24 gives origin and insertion to muscles, 308 in surgical areas, 24 minor details of, 308 of thigh, 307 on back of carpus, 348 dorsal, 23 in foot, 24 iliac and pubic, 308 in the upper extremity, 23 lata, 23 subdivisions of, 308 of Colles, 338 of lower extremity, 23 palmar, 23 pelvic, special names for, 24 plantar, 24 popliteal, 24 special names for, 23 superficial, 23 characters of, 25 of lower extremity, 302 Female generative organs, 291 Femoral canal, 236 fossa, 236 Femoral hernia, 238 ring, 237 sheath, 236 Fibula, anterior surface of, 298 bony parts of, of interest, 298 external surface of, 298 internal surface of, 298 posterior surface of, 298 Fillebrown on opening for antrum, 119 Fissures of brain and their, contents, 139 Flexor longus pollicis, 184 profundus digitorum, 182 Foot and ankle, 298 bony parts of, of interest, 298 and leg, 297 dorsal arch of, 303 long saphenous vein of, 305 nerve of, external cutaneous, 307 long saphenous, 305 middle cutaneous, 306 musculo-cutaneous. 306 short saphenous, 306 short saphenous vein of, 305 Foramen, infra-orbital, 41 mentale, 41 of Winslow, 251 Foramina at base of skull, 128 nutrient, of bone, rule for, 171 of Key, Retzius, Magendie, 124 Forearm, arteries and veins of, 171 biceps of, 185 bones of, 1 68 brachialis anticus of, 185 cubital fossa of, 172 flexor longus pollicis of, 184 profundus digitorum of, 182 sublimis digitorum of, 179 flexors of, 185 median nerve of, 181 muscles of, physiologically grouped, 171 nerves of, grouped, 171 pronator quadratus of, 184 radial artery of, 179 groove of, 172 supinator longus, 185 surgical areas of, 171 ulnar artery of, 177 groove of, 173 nerve of, 182 Frown, complete, 42 G. Ganglion, otic, 91 subtnaxillary, 90 Gasserian ganglion, 129 description of, 131 Genio-hyo-glossus muscle, 8l Geometrical terms and figures, 2O Gland, lachrymal, 139 location of, 147 thyroid, 57 Glands, Pacchionian, 125 Grooves for flexor longus hallucis, 299 H. Hallucis, extensor proprius, 312 Hand, anterior annular ligament, 162 attachment of, 167 perforating arteries in, 166 articular nerves of, and rule, 167 blood-supply of, 1 68 bones of, 152 480 INDEX. Hand, carpal arteries in, 166 cutaneous nerves of, 155 deep fascia of, 157 palmar arch of, 1 68 branch of ulnar nerves in, 165 dissection of, 158 flexor tendons of, 159 hypothenar group of muscles of, 164 infection of fingers of, 167 median nerve in, and dissection of, 162 palmar fascia of, 159 interossei muscles of, 165 radial artery in, 166 sensory nerves of, 167 superficial arch of, 168 surgical areas in fingers of, 167 thecne of, 160 thecal culs-de-sac of, 160 tlienar group of muscles of, 162 ulnar artery in, 166 nerve in, and dissection of, 162 Hepatic artery, 251 Hesselbach's triangle, 233 Highmore, antrum of, 116 analysis of, 116 blood-supply, 117 drainage of, 117 nerve-supply, 117 opening for, 118 Hilton's law, 19 Humerus, bicipital groove and lip of, 171 external condylar ridge of, 171 fracture in middle third of, 171 muscles and ligaments attached to, 171 nutrient foramen of, 171 osteology of, 170 outer and inner surfaces of, 171 posterior surface of, 171 relation of, to musculo-spiral nerve, 171 Hunter's canal, 323 Hyo-glossus muscle, 64 Hyoid bone, movements of, 80 Hypogastric plexus, 273 Hypoglossal nerve, 63 I. Iliac artery, internal, 278 fascia, 275 Iliacus muscle, 279, 289 Ilio-hypogastric nerve, 235 Ilio-inguinal nerve, 235 Inferior mesenteric artery, 257 Inguinal canal, analysis, 230 fossa, 236 hernia, 234 Innominate veins, 475 Intercostal fascia, 201 muscles, 201 nerves, 201 Interior of thorax, 204 Int. TIKI] abdominal ring, 236 cutaneous nerve, 195 mammary artery, 204 ol'!i(|ue muscle, 231 Intestin.-, | : ,rg.- and small, 248 Ischio-rectal fossa, 279 J- Jugular vein, internal, vS superficial, 46 Ju\t;i. 1 ; K. Kidney, descriptive terms of, 260 left, relations of, 259 right, relations of, 258 root-structures of, 259 ureter of, 292 Knee-joint, 440 ligaments of, 442 L. Larynx, 106 arytenoid cartilage of, 108 muscle of, 109 blood-supply of, 1 10 crico-arytenoideus lateralis muscle of, no posticus muscle of, no cricoid cartilage of, 108 crico-thyroid muscle of, 1 10 false vocal cords of, 109 inferior laryngeal nerve of, 109 retiring angle of, 108 superior laryngeal nerve of, 109 thyro-arytenoid muscle of, 109 thyroid cartilage of, 107 true vocal cords of, 109 Latissimus dorsi, 196 Law of projectiles, 21 Levator anguli oris, 32 scapulae, 69 ani, 291 labii superioris, 32 akeque nasi, 33 menti, 34 palati muscle, 98 Ligament, anterior annular, at the wrist and struc- tures under, 162 (foot), 23 relations, 162 external annular, 24 interior annular (hand), 23 internal annular, 24 posterior annular, 23 Ligamenta vaginales of foot, 24 of hand, 159 Ligamentum vaginale, 23 Liver, 253 arteries and nerves of, 255 foetal remains of, 255 how described, 256 ligaments of, 253 root-structures of, 251 Longus colli muscle, 104 Lumbar plexus, 275 Lymphatics of neck, superficial, 46 M. Mandible, 29 Irv.ilors ;m 93 ridge, complete, 27 Temporo-mandibular articulation, 97 Tendo oculi, 140 Tentorium cerebelli, 122 Teres major, 196 and latissimus dorsi, 356 minor, 356 Thigh, fascial septa of, 328 Thoracic aorta, 213 duct, 213, 216 gangliated cord, 216 viscera, posterior view, 214 Thorax, 198 anatomical root of lung, 207 ascending vena cava, 212 brachio-cephalic veins, 212 cardiac and pulmonary plexuses, 214 root-structures, 211 clavi-pectoral fascia of, 200 contents of anterior mediastinum, 208 of middle mediastinum, 209 of posterior mediastinum, 209 descending vena cava, 212 ductus arteriosus, 211 geometry of, 204 hydro-thorax, pneumo-thorax, pyo-thqrax, pyo-pneumo-thorax, 206 inner surface of sternum and ribs, 202 intercostal muscles and fasciae of, 200 nerve, typical, 2OI internal mammary artery, 204 mediastinal spaces of, 208 posterior view of viscera, 214 pulmonary artery, 211 scaleni muscles, 200 subclavius muscle, 200 subdivisions of, 205 Thrombi, septic, 151 Thymus gland, 211 Thyro-arytenoid muscle, 109 Thyroid gland, 157 Tibia and semi-membranosus, 297 articular surfaces of, 297 bony parts of interest of, 297 internal malleolus of, 298 surface of, 297 oblique line of, 298 posterior surface of, 297 vertical line of, 298 Tibialis anticus, insertions of, 299 posticus, insertions of, 299 small insertion of, 299 Tissues, anatomical, 13 connective, 14 forms of, 14 constituents of, 15 muscular, 13 Tissues, nerve, 14 resume of, 16 Tongue, dissection of, 79 movements of, 8 1 Tonsil, 87 Toothache in the ear, 92 Trachea, no blood -supply, ill nerve-supply, in relations of, III structure of, I IO Transversalis muscle, 232 Triangular space, 355 Trituration, muscles of, 93 Tubercles, supra- and infra -glenoid, 186 Tympanum, or middle ear, 131 dissection of, 135 facial nerve in relation to, 133 geometric analysis of, 132 importance of, 132 Typical rib, osteology of, 201 U. Ulna, anterior surface of, 169 internal surface of, 169 osteology of, 169 posterior surface of, 169 vertical line of, 170 Ulnar nerve, 182, 195 paralysis of, 167 Urethra, 334 V. Veins, angular and ophthalmic, 39 axillary, 475 brachial, 475 cephalic, at the shoulder, 166 in venesection, 166 cerebral, 126 classification of, 138 common temporal, 474 communication between the superficial veins and the deep veins, 166 external jugular, 474 facial, 6l, 474 innominate, 475 internal maxillary, 474 jugular, internal, 58, 474 long saphenous, 476 median, 156 occipital, 474 of the face, 39 of the lower extremity, 476 deep, 476 of the upper extremity, 475 portal, 476 radial, 155 some interesting facts about, 473 subclavian, 64, 475 superficial, of forearm, 155 termination of ulnar, median, radial, 166 ulnar, 156 Vena azygos major, 216 cava, ascending, 212, 476 descending, 212 superior, 475 Venae comites, 166 Venesection, criminal liability in, 167 Vesiculse seminales, 339 Vestibule of oral cavity, 85 Vincula, 161 Viscera, posterior view of, 214 Vocal cords, true and false, 109 W. Winslow, foramen of, 251 DATE DUE SLIP UNIVERSITY OF CALIFORNIA MEDICAL SCHOOL LIBRARY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW I 4- 12 000 P OCT 2 6 - 1941 Uv a 1941 KB 1 4 1943 JUN 2 y 1943 JUL J943 SEP * - 1943 AUG ^ i 1344 MAR 1 3 1948 V A U949 2m-5,'31