The Surgery of the Skull and Brain

CHAPTER XI

TUMOURS OF THE SKULL-BONES 325

INDEX 335

LIST OF ILLUSTRATIONS

FIGS. PAGES 1 and 2. Cranio-cerebral topography 2, 3 3. The cortical motor and sensory areas 8 4 and 5. The scalp-tourniquet 14, 15 6. Cushing’s ‘clips’ 18 7. Hudson’s trephine 20 8. The hand-trephine 21 9 and 10. The technique of trephining 22 11-16. Instruments used in trephining 23, 24 17-19. The formation of an osteoplastic flap 26, 27 20. An occipital cephalocele 33 21. A cephalocele over the anterior fontanelle 35 22. An occipital cephalocele 37 23. A depressed birth-fracture 45 24 A and B. A case of depressed birth-fracture, before and after operation 47 25. To illustrate the effects and position of a birth-hæmorrhage 53 26. The author’s operation for Hydrocephalus internus 64 27. The conversion of Hydrocephalus internus into cephalocele 65 28. Illustrating the lines along which forces received on the vault are transmitted to the base 69 29 A and B. The base of the skull and the base as seen on transillumination 70, 71 30. Plan of the base of the skull 77 31. To illustrate the relation of basic fractures to cranial nerves 81 32-37. The lines pursued by basic fractures 83-8 38 A and B. To illustrate the probable source of profuse hæmorrhage from the ear 97 39. To show the relation of a typical basic fracture to the middle ear and its adjuncts 103 40 and 41. To show the relation of basic fractures to the petrous bone 104, 105 42. A comminuted fracture of the skull 112 43 A and B. An explosive fracture of the vault of the skull 113 44. A temperature chart illustrating the changes in temperature observed in head-injuries 117 45-48. Intermusculo-temporal cerebral decompression 122, 123 49 A and B. The elevation of a depressed fracture of the vault 131 50 A and B. The inner aspect of the skull and the same seen on transillumination 137 51. To illustrate compression of the brain as produced by an extra-dural hæmorrhage from the middle meningeal artery 141 52 A and B. The operative treatment of middle meningeal hæmorrhage 144, 145 53. A basic fracture with laceration of both carotid arteries 148 54. A basic fracture with laceration of the cavernous sinus 149 55. A basic fracture with laceration of both lateral sinuses 151 56 A and B. The operative treatment of subdural hæmorrhage 156, 157 57. The areas concerned in speech expression 163 58. The cortical motor and sensory areas 165 59. The König-Müller osteoplastic flap 197 60. The author’s method of covering in a gap in the skull 199 61. A case of traumatic orbital aneurysm 207 62. A glioma of the brain 211 63. A sarcoma of the brain 211 64. An endothelioma of the dura mater 212 65. A fibroma of the dura mater 212 66. An acoustic tumour 213 67. Symmetrical tuberculomata 214 68. The cortical motor and sensory areas 220 69. The visual paths 223 70. A pituitary tumour 226 71 A, B and C. The exposure of a tumour by osteoplastic flap 230, 231 72. Combined flap formation and decompression 235 73 A, B, C and D. The exposure of a cerebellar tumour by craniectomy 239-41 74 A and B. To illustrate the extension of disease from the tympanic cavity and the surgical anatomy of that region (after Hunter Tod) 251 75. A large right-sided temporo-sphenoidal abscess 256 76. To illustrate the pressure effects of a temporo-sphenoidal abscess 257 77. A cerebellar abscess 259 78. To illustrate diagrammatically the symptoms observed in cerebellar abscess formation (after Luciani) 261 79. The exposure of a temporo-sphenoidal abscess 265 80. The ‘radical’ mastoid operation (after Hunter Tod) 269 81. Exploration for a temporo-sphenoidal abscess (after Hunter Tod) 270 82. Exploration for a cerebellar abscess (after Hunter Tod) 271 83. A fracture of the anterior fossa which was followed by the development of meningitis 275 84. Basal meningitis secondary to temporo-sphenoidal abscess 277 85 A and B. To illustrate the exposure of the lateral sinus (after Hunter Tod) 285 86. A case of Hernia cerebri and the abscess after removal 292 87. Diagrammatic illustration of the three forms of ‘gutter’ fracture 297 88. Diagrammatic representation of the effects produced on bone and brain by a perforating bullet-wound 299 89 A and B. Sheen’s bullet probe, forceps, and telephone bullet-detector 302, 303 90. To illustrate the operations on the Gasserian ganglion 317 91. To illustrate the operations for exposure of the Gasserian ganglion 321 92. Ivory exostoses of the skull 326 93. The development of the frontal bone 327 94. An exostosis of the orbit 330 95. An extrinsic sarcoma of the skull 331 96. An intrinsic sarcoma of the skull 333

THE SURGERY OF THE SKULL AND BRAIN

CHAPTER I. Cranio-Cerebral Topography

CRANIO-CEREBRAL TOPOGRAPHY

The surgeon who is called upon to carry out operations on the skull and brain must possess an accurate knowledge of the anatomy of the parts involved. Added to this, he must have at his command some simple method of depicting on the surface of the skull the more important structures.

The more complicated systems of cranio-cerebral topography are of little practical value to the surgeon. Simplicity is essential, and the following outline will be found to furnish an adequate practical guide.

Firstly, the skull can be divided into two lateral halves by the surface-marking of the superior longitudinal venous sinus.

=The superior longitudinal sinus.= This sinus originates at the crista galli and, passing backwards along the attached margin of the falx cerebri, terminates at the internal occipital protuberance. It may be represented by a line drawn from the base of the nose (the nasion), over the vertex of the skull, to the external occipital protuberance (the inion)--this line corresponding in its course to the occasionally persistent metopic suture between the two halves of the frontal bone, to the sagittal suture between the parietal bones, and to the middle line of the upper or tabular portion of the occipital bone.

Secondly, each lateral half of the skull can be subdivided into supra- and infratentorial regions by a line which marks the external attachment of the tentorium cerebelli; in other words, by the line of the lateral sinus.

=The lateral sinus.= This sinus is represented by a line presenting a slight upward convexity, which is drawn from the external occipital protuberance to the upper and posterior part of the mastoid process of the temporal bone.

=The infratentorial region.= The cerebellum lies wholly beneath the tentorium cerebelli, and it is obvious that, in operations carried out over this portion of the brain, the surgeon is limited in his field of exposure, above by the line of the lateral sinus, and on either side by the posterior border of the mastoid process. The division between the halves of the cerebellum may be represented by a line drawn vertically downwards from the external occipital protuberance to the nuchal region. This line also represents the surface-marking of the occipital sinus and falx cerebelli.

=The supratentorial region.= Brief allusion must be made to certain landmarks that aid in the representation of structures situated in this region:--

(a) The external angular frontal process. The suture between the external angular frontal process and the corresponding process of the malar bone lies immediately above the central point of the outer border of the orbital cavity.

(b) The malar tubercle. A slight prominence on the posterior border of the frontal process of the malar bone, about ¹⁄₄ inch below the external angular frontal process.

(c) The temporal crest. A prominent ridge that is directed upwards and backwards from the external angular frontal process. The crest cuts across the lower portion of the parietal bone, passing below the parietal prominence, and curves downwards towards the upper and posterior portion of the mastoid process. It terminates by becoming continuous with the upper root of the zygomatic process. The crest consists of two parts, the upper and lower temporal crests. To the upper is attached the temporal fascia, to the lower the temporal muscle. The lower crest is almost invariably the more prominent.

(d) The parietal prominence. The central and most prominent part of the parietal bone. It indicates the point at which ossification commenced, and lies about ³⁄₄ inch above the termination of the posterior horizontal limb of the fissure of Sylvius.

(e) The zygoma. When traced in the backward direction, the zygoma is found to divide immediately in front of the ear into three roots, of which the anterior, merging into the eminentia articularis, and the middle, aiding in the formation of the post-glenoid process, are of no practical utility in surface-marking. The upper or posterior root sweeps backwards above the external auditory meatus to become continuous with the suprameatal and supramastoid crests, the former of which forms the upper boundary of Macewen’s suprameatal triangle, a triangular depression at the upper and posterior border of the external auditory meatus. This triangle may be taken as representing the opening of the mastoid antrum into the middle ear.

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