./^, KD5"^5 U^45 tntI)e€ttpotlmgork CoUege of ^tjpgictans; anti ^urgeonsf Hiiirarp ^ V Digitized by tine Internet Archive in 2010 with funding from Open Knowledge Commons http://www.archive.org/details/warsurgeryofnervOOunit WAR SURGERY OF THE NERVOUS SYSTEM A DIGEST OF THE IMPORTANT MEDICAL JOURNALS AND BOOKS PUBLISHED DURING THE EUROPEAN WAR COMPILED BY THE DIVISION OF BRAIN SURGERY SECTION OF SURGERY OF THE HEAD OFFICE OF THE SURGEON GENERAL War Department : Washington, D. C, 1917 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 L', , f Vt«4?( TABLE OF CONTENTS. Page. Preface 5 Chapter I.— HEAD. Part 1 . Fractures of the skull 7 2. Meninges, ependyma, and brain 27 3. The vestibular apparatus in the diagnosis of intracranial disease 85 4. Abstracts from foreign war literature Ill Chapter II.— SPINE. Part 1. Sui'gical anatomy of vertebral column and spinal cord 205 2. Normal and pathological physiology of the spinal cord 213 3. Localization of motor, sensory, and reflex functions in the different segments of the spinal cord 218 4. The symptomatology of spinal disease 222 5. The symptoms of spinal disease at different levels and in different regions of the cord : 229 6. The operation of laminectomy 234 7. Abstracts from foreign war literatiu'e 247 Chapter III.— PERIPHERAL NERVES. Part 1. Diseases of the peripheral nerves 301 2. Abstracts from foreign war literature 336 3 PREFACE. This manual represents an atte)ni)t to collect, digest, and arrange in orderly form, the literature of war surgery of the skull, brain, spine, spinal cord, meninges, and peripheral nerves, from August, 1914, to August, 1017. The sources of supply were the English, (mer- man, and French Aveekly, monthly, and quarterly medical journals, and those foreign treatises dealing with war surgery as practiced and observed during the present conflict. The scheme adopted has been based largely on the plan of the collective abstract. It was thought wise to furnish fairly full ab- stracts, in order both to avoid unw'arrantable dogmatism, and also in order to allow the reader free scope of personal interpretation. For this latter reason also, the editor has refrained both from extended critique and from attempting generalized conclusions, by way of summary. Xo abstracts on the subject of Roentgenology have been furnished for the reason that special schools are equipping men for this work. The following are satisfactory references: A. G. Straw, Arch, of Radiol, and Electrother, May, 19|T, p. 393 ; W. Oram, At^oh. of Radiol, and Electrother. February, 1917, p. 277; H. E. Gamlem, Arfih. of Raddol. and Electrother^ November. 1916, p. 175; Gage, Arch, of Radiol, and Electrother., June, 1917, p. 1 ; E. Skinner, Amer. Jour. Roent.., June, 1917, p. 350; George H. Makins, Brit. Jour, of Surg., June 16, 1917, p. 803. Since the war hospitals may not be Avell supplied with books, we have introduced the abstracts w'ith selections from standard text- books, so that the reader of the manual might be always in close touch with fundamentals. For the brain, we have used the chapters from Keen's Surgery w^ritten by Dr. Harvey Cushing, and chapters from; Dr. Isaac H. Jones's forthcoming book on Equilibrium and Vertigo. For the spine w^e have used selected chapters from Dr. C. A. Elsberg's book on Diseases of the Spinal Cord and its Mem- branes, and Dr. Charles H. Frazier's volume (in press) on Surgery of the Spine, and for peripheral nerves we have selected the chapter on peripheral nerves, wn-itten by Dr. Gordon M. Holmes for Osier's Modern Medicine. The use of the phrase *' war surgery " must be taken with a good deal of qualification, lest one fall into the error of thinking of this type of work as separate and distinct from the surgery of civil life. 5 6 WAR SUEGEEY OF THE NEEVOUS SYSTEM. As a matter of fact the surgical principles governing both are in large part exactly the same. The laws of ballistics, trench life, the terrain of the battle field, the problems of transport, and numerous other incidentals serve to modif}' established principles of surgery, but not. more than that. Indeed nothing demonstrates more clearly the truth of this statement than the fact that war surgery makes such free use of those aids Avhich, in civil surgery, are indispensable for both the laying down and following out of principles— bacteriolog}% serology, roentgenology, and the general routine of clinical mi- croscopy. Thanks are extended to the editor of Surgery Gynecology and Obstetrics for the permission to use abstracts from this journal. As a result of this much-appreciated courtesy Ave Avere able to complete an emergency task within a necessarily verj^ short time limit. Thanks are also extended to J. B. Lippincott Co. for the privilege of quoting from Dr. Isaac H. Jones's forthcoming book, Equilibrium and Ver- tigo: to W. B. Saunders Co. for the privilege to use Dr. Harvey Cushing's contribution to Surgery, Its Principles and Practice, edited by William Williams Keen^ M. D., and Diseases of the Spinal Cord and Its Membranes by Charles A. Elsberg, M, D. ; to Lea & Febigei- for the privilege to use Dr. Gordon Holmes's contribution to Modern Medicine, edited by Sir William Osier, M. D., and Thomas McCrae. M. D. : and finally, to D. Appleton & Co., for the privilege to use the chapter from Dr. Charles H. Frazier's forthcoming volume on Dis- eases of the Spinal Cord. We feel a deep sense of obligation to all these authors, from whom we have draAvn so freely. It was unfortu- natel}^ impossible to communicate directly with Dr. Cushing or with Dr. Holmes, in order to secure from them an expressed willingness, which Ave Avere sure they Avould accord us if time permitted. Chapter I. SURGERY OF THE HEAD. (Parts 1-2 from Dr. Hakvey Cushing's contribution to Surgery, Its Principles and Practice. Edited by W. W. Keen, M. D. ; published by W. B. Saunders Company. I Part 1. FRACTURES OF THE SKULL. Terminology. — The skull may be said to be fractured in distinction to its being- wounded when, as the result of a blow, it becomes cracked or broken into more or less separate pieces. These injuries are classi- fied in a variety of ways: (a) According to the mechanism of their production. (h) According to the presence or absence of a communicating wound. (c) According to the form assumed bj^ the fragments. (d) According to their situation. (a) Depending on the mechanical factors at work in their pro- duction, they are distinguished as (1) bursting fractures and (2) fractures due to local depression or indentation — so-called bending fractures. In the case of fractures the result of penetration by mod- ern high- velocity projectiles a further mechanical element comes into play, producing expansion fractures through the explosive force of hydrodynamic action. (b) Fractures are ojjen or compound when they are exposed by a wound of the overlying soft parts; they are simple or closed when the soft tissues covering them remain intact. (c) According to their form they are distinguished: As linear or fissured fractures when the bone is merely cracked without displace- ment ; as a fracture by diastasis when there is a simple separation of the sutures; as cormninuted or fragmented, fractures when the lines of fracture intersect, so as to isolate separate particles of bone; as depressed fractures when fragments of bone, whether of the entire cranial thickness or of the inner table alone, are driven below their spherical level; as perforating fractures or fractures loith loss of sub- 7 8 WAR SURGERY OF THE NERVOUS SYSTEM. stance when they are the result of punctured wounds or when the fragments at the seat of the penetration have been carried away, leaving a defect, as is the case in most penetrating bullet wounds. And of these chief varieties many subdivisions may be made. {d) Lastly, depending roughly on their anatomical situation, they are distinguished as fractures of the lyase and fractures of the vault, and although the two are often combined they may exist separately and have different characters. Thus, fractures of the base are usually linear and their fragments, if comminuted, are rarely displaced, for the base is much less accessible to direct injury; hence, fractures there are usually the indistinct result of violence applied elsewhere. On the other hand, the vault is directly exposed to injury and local comminu- tion with dislocation of fragments is common, and as the bone is thick and has two determinable layers there are special influences which modify the character of the fragmentation. {a) The mechanism of fractures — Bending, bursting, and expansile fractures. — Regarded as a hollow shell of bone which possesses elas- ticity sufficient to rebound when dropped, the cranium must needs differ from all other bones of the skeleton in the mechanism of its injuries. Certain of the physical laws which explain the peculiar form assumed by these injuries are known to us; others are still in dispute, and though, from a strictly clinical point of view, of chief importance is the knowledge that under certain conditions breaks occur in a certain manner and lead to certain complications, we nat- urally search for an explanation of the reason why they so occur, even though this information may in no Avise affect our diagnosis, prognosis, or treatment. Teevan, Wahl, Rauber, Felizet, Aran, Bohl, Bruns, Bergmann. Kocher, and a host of others have undertaken clinical and experi- mental investigations directed toward the elucidation of the under- lying principles governing cranial fractures. We must take into consideration the double effect of an impact, for the blow may produce (1) disturbances which are direct and chiefly of local consequence, and (2) those which are indirect and lead to solutions of continuitj'^ at a distance. Setting aside for the moment its irregularities and considering the skull to be an elastic globe, an impact will momentarily lessen its diameter in line of the blow, and force nearer together the point or pole of impact and the point on the sphere diametrically^ opposite. As the impact forces the poles together it will at the same time bulge out the sides of the sphere and thus increase the equatorial circumference and, in a lesser degree, the circumference of all the other circular planes which lie perpendicular to the polar diameter. If the distortion following the impact is in- considerable the skull, owing to the elastic rebound, will resume its former shape unimpaired. If the distortion, on the other hand, is FRACTURES OF THE SKULL, 9 SO great as to overcome the molecular cohesion of the bony particles, they will be disrupted. This may take place (1) as a rupture or bursting of the bone in parts remote from the poles of impact where cranial dimensions have been increased to the point of overcoming tensile strength of the particles, and (2) as a local indentation at the pole of impact where cranial dimensions ha\e been diminished to the point of overcoming the local resistance of the particles to pressure. These two qualities of elasticity' — tensile strength and resistance to pressure — have been the objects of special study hy Eauber, who has shown that resistance to pressure is a third greater than tensile strength. This, however, does not mean that fractures are less likely to occur at the pole of impact than at a distance, for other factors come into play. Local character of injuries through bending. — These fractures usually result from the sharp impact of a body with a comparatively small surface. Such a blow expends its force quickly and a rebound occurs before the form of the skull, as a whole, has been sufficiently altered to produce lesions at a distance. At the pole of impact the bone is broken and the displaced fragments do not resmne their former position. In spite of its greater thickness and vaulted construction fractures of this sort are more common on the exposed calvarium than at the inaccessible base. The character of the lesion, furthermore, is in- fluenced by the structural peculiarity of the bone; namely, its two dense tables separated by a spongy diploe. Owing to this, an in- dentation which leads to a bending fracture will cause the inner table to splinter and give way before the outer. In consequence we not infrequently find fractures limited to the inner table — a circum- stance known even to the earliest writers in medicine, who explained the phenomeon on the supposition that the inner table was more fragile or brittle than the outer one, hence the " vitreous " surface. Xot until Tee van's studies was the process satisfactorily explained on the ground of tensile strength or cohesion of particles on the one hand and of resistance to pressure on the other. There is no simpler illustration than the oft-used one of a green stick broken across the knee. The cranial impact leads to a local indentation, which tends to pull apart the particles comprising the inner table and to drive together those of the outer. In certain rare cases the process may be reversed and the outer table alone sutler ; this implies a blow from within. Both Teevan and Bergmann have given in- stances of such lesions; thus, after traversing the cranial cavity, a spent bullet may strike the inner surface of the skull and fracture the overlying outer table alone. If the force of the blow has been expended by the time the inner tJible gives way, it alone suffers fracture: if it continues, the outer I'O WAR SUKGEEY OF THE NERVOUS SYSTEM. gives way as Avell, but in the latter case it is always to be borne in mind that the inner table splinters over a wider area than the outer. A lesion Avhich is limited to the inner table alone can only occur in a skull well provided with diploe, and consequently in infancy and old age the bone will usually give way throughout its entire thickness at the same moment. These bending fractures may be associated Avith little or no dis- placement of fragments; they may, on the other hand, lead to a marked depression whose floor is made up of firmly wedged frag- ments from the two tables. They, furthermore, are usually bounded by an irregular circular fissure, into which lines of fracture radiate from the central point of impact. An excellent example of such a circular fracture from bending occurs among the comparatively rare instances of this form of fracture at the base, when, as the result of a fall upon the buttock the impact is transmitted to the occipital bone through the spinal column, and the circular fracture more or less clearly surrounds the foramen magnum. Distant effects of injuries through bursting. — A diffuse blow from a fiat surface is prone to cause effects at a distance, just as a concen- trated one from a small body is apt to produce local effects. A burst- ing fracture of typical form, comparable to the lesions, which Von Bruns has produced experimentally by compressing skulls in a vise tc the point of fracture, was cited in the clinical note given above, but it is unusual for the head to be caught and squeezed in this way. An analogous injury may occur when, lying on a hard surface, it is struck by a falling body, though a violent blow against one side of the cranium alone — the head itself usually being the moving force — is the more common method. Though the striking surface, favorable for a bursting effect, should be a fiat one, it is common enough for some forms of impact, which produce primarih^ an indentation, to cause a bursting of the skull as well, in case there is no immediate rebound and if the force exerted be sufficient. Thus, we often find meridional fissures which radiate from a local bending fracture situ- ated at the pole of impact or, indeed, even in the absence of a polar fracture. Thus, most fissured fractures are an expression of the indirect or bursting effect of a blow, and inasmuch as the base of the skull is more fragile than the vault these fissures occur most readily in this region. Having oftentimes no apparent connection with any lesion at the point of impact they naturall}^ are spoken of as the indirect result of violence. The view that these injuries at a distance are due to the effects of a counterinjury or contrecoup — a term introduced by French sur- geons in the latter half of the eighteenth century — is one which re- mains popular, though it has been shown to be mechanically wrong. FRACTURES OF THE SKULL, 11 We leai'ii from thei^e obser\ iilidns that bursting fractures need not be associated with any disphicement of l^one. but that linear cracks occur wliich haAe a tendency to lain into the nearest weak portion of the cranial base. These cracks oi- fissures enter the middle cranial fossa- more often than the anterior or posterior, and it is Walton's view that they often seek out the sella turcica, which pre- sumably is the weakest point of all. There are factors other than those already mentioned which are thought to modify the direction of these cracks from bursting. Among them are the foramina and the sutures. Whether the frac- tures tend to seek or to avoid the l)asal foramina is a matter of dispute. It seems to depend upon the relative strength of the rim of the foramen and the neighboiing bone. When the rim is thick- ened and strong, even so large a defect as the foramen magnum need not be an evidence of local weakness: no more need a trephine opening in the vault in any wa}^ weaken the elastic strength of the cranial sphere. Nevertheless, there are certain foramina which are apt to be involved, as the posterior lacerated space, the foramen ovale, and the facial and acoustic foramina. The sutures, on the other hand, often serve to deflect fissures from the direction which they should have taken by mechanical laws. This is especially true for the skulls of young individuals. (See Fractures by Diastasis.) The explosive effect of hydrodynamic force. — The introduction of the modern firearm, with its peculiar nondeforming, hard-mantled projectile, has brought an entirely new element into the mechanism of penetrating gunshot wounds, particularly^ those involving the cranium. It has been made the subject of special study by Kocher, von Bruns, Coler. and Schjerning. When such a projectile, with its extreme initial velocity and great penetrating power, traverses the incompressible semifluid brain, inclosed as it is within a solid covering, it exerts an enormous explosive (hydrodynamic) force against the inner cranial surface. W^ere the cranial chamber empty a simple penetrating wound of entrance and exit would result, but, being full, the tremendous force is transmitted against all points of its inner surface, and consequently'' its walls become shattered into fragments. (h) Clinical varieties of fracture. — By the qualification simple or compound or, possibly better, open or closed^ we indicate, as in skeletal lesions elsewhere, that the fracture is covered by intact soft parts or commvmicates Avith the air through an external wound. The distinction is po&sibly of less vital significance than formerly and, indeed, here more often than in any other part of the body we deliberately, by operati^■e explorations, turn simple fractures into 12 WAR SUEGERY OP THE NERVOUS SYSTEM. open ones for the replacement of dislocated fragments or to avoid other complications. In compound fractures of the base, however, Ave are almost as helpless in the prevention of infection as were our predecessors; for when these injuries communicate with the ear. the pharynx or the sinuses accessory to the nasal cavity, Avhere patho- genic organisms lurk, a doorway which we can not reach is opened to infection. A compound fracture of the base from other cause than bursting is unusual, though it may occur when a weapon, a bullet, or other missile has entered the skull from below. In such a case careful surgical cleansing and drainage is demanded. Fractures according to their form. — Fissured or linear fractures, as we have seen, are the usual result of bursting; they tend to take a meridional course, radiating from the pole of impact, and. further, owing to its structural weakness, they more commonly occur at the base. When the skull resumes its former shape, after the moment of deformation which causes the bones to spring apart, the fissure will close tightlj^, provided there has been no associated fragmenta- tion. At the moment of separation of a fissure, substances like hair, portions of headgear, or pieces of the missile which inflicted the bloAv may either be introduced wholly into the cranial chamber or be caught in a vicelike grip when the edges again snap together. It acts like the " meridional " crack in a child's hollow rubber ball, which gapes when its poles are compressed. A fissured fracture may occur as a single linear crack, it may fork or branch, or there may be multiple fissures radiating from the point of impact. A simple linear fissure may close so snugly as to be diffi- cult of detection even on direct exposure. Attention may be called to it, hoAvever, by the extrusion, along the closely approximated edges, of fine drops of blood. After death this does not help and at autopsy fissures may escape other than the closest scrutiny. In other instances, whether from interposition of tissue or from some dis- location of fragments, an extensive meridional crack may continue to gape. Such a condition, especially when the fissure has included the vault, may be detected by percussion, or Avhen the head has been shaved, by auscultation combined with percussion, the blow eliciting a " hollow-cask " sound. Furthermore, there will be tenderness along the line of fracture, though this is of little aid in unconscious pa- tients. It is to be remembered that sutures are often mistaken for fissures. Linear fractures, though simple in themselves, are especially prone to be accompanied by intracranial complications, for their very presence indicates a diffuse bloAV the effect of Avhich is usually Avide- spread. Hence cerebral contusions are common. The fissures often run across the meninseal grooves and lead to extradural extravasa- FRACTURES OP THE SKULL. 13 tions and more or less subdural hemorrhage is the rule in the linear fractures of the base. The treatment, therefore, resolves itself into the treatment of the complications rather than of the fracture, viz, the evacuation of the clot in an extradural hemorrhage; the drainage of the cerebrospinal space if subdural hemorrhage or edema has been sufficient to cause bulbar symptoms. Fractures by diastasis. — Linear fractures may be deflected into one of the sutures, due to the fact that, before the complete obliteration which they may undergo late in life, they offer less resistance to the cranial deformation than does the bone elsewhere. In the young the lesion may occur as a true separation of the bones. I have seen at operation upon a child of 12. whose head some days before had been caught and laterally squeezed, a simple diastasis of the coronal suture, which had torn the dura, leading to the escape of cerebro- spinal fluid under the scalp (spurious meningocele) ; at no time had there been any cerebral symptoms. In the adult, on the other hand, the process is necessarily more than a simple diastasis, for union is so firm, owing to the close dovetailing of the irregular bony margins, that separation of the sutures can not occur otherwise than by a break. Comminuted fractures are those characterized by more or less frag- mentation or splintering. The comminution may be confined to the area of impact or the entire cranium may be broken into pieces. Being a common result of local deformation or inbending at the point of injury, they are usually situated on the vault and depend for their production on the character not only of the blow (a sharp one with quick rebound) but also of the striking body. From the standpoint of the bony lesion itself they are more serious than linear fractures, owing to the usual displacement of fragments — ■ fractures with depression. Extensive comminution, however, may occur with little, if any, dislocation of the broken pieces. We may, ' furthermore, in the elastic skulls of infants have depression with no comminution or, indeed, with a total absence of fracture. Finally, in certain rare cases, fracture may occur with actual elevation of a fragment. These effects, however, are unusual; comminution and depression commonly go hand in hand. Hence they will be con- sidered together. The comminution and depression may affect the inner table alone or both tables, in which case the fragments may consist of the entire thickness of the skull or, in diploetic skulls, of the separated tables. When thus separated the fragmentation of the inner is always more widespi-ead than that of the outer. The fragments may form a cup- .shaped depression, often termed by English writers " pond fracture," 14 WAR SURGERY OF THE NERVOUS SYSTEM. or the}' may become tilted at the periphery and slip imder the intact cranial edge.' We thus have perrpherul or central depressions. From the pole of impact in comminuted fractures there are often numerous radiating or meridional fissures; these in turn are often connected by zonal lines of fracture, like the connecting strands of a spider's web ; and in these cases the farther from the point of impact, the farther apart are the zonal lines, and consequently the larger the fragments. When comminution is the result of diffuse blows, as in the skull of the " butting " negro in the Surgeon General's Museum, or when it follows falls from a great height, irregular fragmentation, like a broken eggshell, may occur, with fissures having no definite configuration. Almost all punctured or penetrating wounds are accompanied by more or less local fragmentation, with depressions, which particu- larly affects the inner table. Depressed fragments may heal in place and their irregularities become, in the course of time, largely smoothed off. Perforating fractures are due to cuts, to stab wounds, to the ]Dene- tration of sharp tools which have fallen from a height, to the blow of a pick, the thrust of a bayonet, and what not. They are associated with more or less fissuring, with fragmentation, and Avith depression of fragments, especially of those broken from the inner table about the margin of the wound. Their course, diagnosis, complications, and treatment do not differ materially from that of wounds of the skull (p. 63), unassociated with fracturing, though produced by simi- lar agencies. When a portion of bone has been carried away, leav- ing a defect, they are called fractures with loss of substance. One particular group of perforating fractures deserves special con- sideration; namely, those which are the result of wounds from fire- arms. Grunshot fractures.— In their simplest form these are perforating fractures \A'hich pi'ocluce a circular loss of substance. When the re- sult of a Avound at short range from the modern small arm, we have seen that the skull may be burst outward by the explosive action of hydrodynamic pressure. We have learned, too. that these are com- pound or open fractures; that they are aluiost always comminuted ones with some depression of fragments: and, finally, that they often lead to sepsis, hemorrhage, or other intracranial lesions, which make of them a particularly dangerous and crippling form of injury. There are, however, other types of gunshot fracture less serious, since they are nonperf orating. Thus, the direct impact of a heavy spent ball may fissure or indent the skull without producing more than a bruise of the scalp. Again, a bullet may pass through the scalp and graze the A'ault in a tangential direction without penetra- tion, or it may furroAv the bone, scooping out a gutter in the outer FRACTURES OF THE SKULL, 15 table alone or Ivaviiig- a defect of the entire cranial thickness. The lateral force exerted, during its rapid flight, by the modern liigh- velocity projectile is sufficient to comminute the skidl, even if it be merely grazed, so that only in those localities where the bone is thick and porous or contain air cells Avould it be likely to escape consider- able local fragmentation from such a tangential wound. For the same reason fractures of the base may occur when a bullet traverses the shell-like bones comprising the under surface of the skull without actually penetrating the cranial chamber; and. further, bullets may become lodged in the thicker parts of the cranial wall and produce more or less local comminution Avithout actually entering the cavity. The wound of the bone, as we have seen, may show nothing more than a clean-cut circular or oval loss of substance, but it is the rule for the wounds both of entrance and exit, in case they occur in bones containing diploe, to show the particular cliaracteristics of punctured fractures; that is, to have a more or less splintered margin, particu- larly of the table which has been last penetrated — the inner table for the wound of entrance, the outer table for that of exit. Hence, when there is a loss of substance due to the actual carrying away of frag- ments, the circumference of the defect will be greater on the side from which the missile has emerged, whether it be wound of entrance or exit — a matter often of medicolegal importance. Furthermore, meridional fissures are apt to radiate from the wounds of impact, and these meridians in turn are often joined by circular fissures on zonal planes. The damage from perforating bullets depends partly upon the physical properties of the missile and partly upon the speed with which it is traveling. There is great difference, therefore, between the effects of the soft, leaden bullet discharged from a revolver and that of the modern conical projectile with its hard mantle and tre- mendous initial velocity. The latter missiles, except near the end of their flight, rarely lodge; the former almost invariably do. Ill liis Handhuch der Praktischen Chirurgic, Bergmann gave in full the results of experlmeuts conducted by himself and others upon wounds of the head made by the modern rifle. Briefly, it may be said that at close range the skull and scalp are literally torn to pieces and the brain disorganized ; that on penetra- tion at 50 yards the scalp remains intact, though the skull is greatly com- minuted and brain tissue oozes both from the wound of entrance and exit; at 100 yards there occur zonal fractures wliich tend to be limited to the area about the wounds of entrance and exit, while meridional fissures radiate from these points, showing that explosive action is still effective; at 1.000 yards the zonal cracks encircling the bullet holes disappear, and only the radial fissures remain; at tlie distance of 1 mile the fissures largely disappear, leaving the two clean-cut bullet holes; and not until over li miles does the projectile fail to emerge after entering the skull on one side. All this, of course, is merely relative, for there would be great difference, not only in individual skulls but 16 WAB SURGERY OF THE NERVOUS SYSTEM. in the position in whicli they were struck ; and it is, after all, a matter chiefly of interest to the military surgeon. On the wliole, these wounds in warfai-e liave a grave prognosis. According: to Fischer's statistics from tlie German Army during the Franco-Prussian War, 45 per cent of 8,132 gunshot injuries resulted in immediate death, and nearly one-half of those found dead ou the held of battle had wounds of the skull. The gunshot fractures which are seen in civil life are more apt to result from revolver shots and in orderly communities to be self- infiicted wounds, whether by accident or intent. Here again the char- acter of the injury depends upon the nature of the weapon and the initial velocity of the projectile. Most of the wounds which one sees to-day are produced by soft bullets fired from the ordinary revolver with no great initial momentum; the heavier army pistols, on the other hand, fire a projectile which at near range has the explosive effect of a rifie. The soft, deforming revolver bullets are apt to lodge either in the bone at the site of entrance or somewhere within the cranial cavity, either at some point in the direct line of their flight or, in case the missile has rebounded, at some point in a line deter- mined by the angle of deflection from the opposite inner surface. At times the course of such a deflected bullet may be mathematical!}^ calculated, but to-day the ,r-rays give us a more accurate means for determining its position. It may be said, however, that, as a rule, there is no particular reason for its extraction, for in the absence of immediate complications it becomes encapsulated and, unless the mis- sile chance to lie near the surface, the damage already done will only be increased by meddlesome attempts to locate and extract it. The complications which result from penetrating bullet wounds ma}^ be classified as imm-ecUate^ or those clue to hemorrhage, com- pression, and destruction of tracts ; intermediate^ or those due to sep- sis; and late symptoms (irritative and paralytic), giving evidence of the permanent damage done to the cerebral tissues. Hemorrhage, of all the immediate symptoms, is especially to be dreaded, as it may lead to rapid death from compression. In all cases in which there is an increase in intracranial tension from efi^used blood, the pressure forces the disorganized nervous tissue through the wounds of entrance and exit, and the extruded particles of white tissue are found mingled with the blood which oozes from the opening. It is not uncom- mon for cranial nerves to be injured, either by direct section or by implication in a basal fracture. It is notorious that suicides often fail to accomplish their purpose. Brun has recorded 32 cases, of which number 16 recovered. Of these cases the wound of entrance was in the right temporal region sixteen times, in the left twice, in the forehead nine times, and in the mouth twice. The " temple " is regarded by the laity as a partic- ularly'- vulnerable spot, which accounts for the preponderance of the attempts in this situation. In them oftentimes the bullet merely FRACTURp]S OF THE SKULT.. 17 passes extra-cranially from temporal fossa to temporal fossa, through the back of both orbits, cutting the optic nerves and leading to blind- ness — a sad penalty for a criminal act. Though unrecorded in Brun's series, suicidal wounds inflicted in the right mastoid region are not uncommon. The later complications, in case of " recovery," are paralyses, men- tal changes, epilepsy, etc. Thus, a patient was accidentally shot in the mid -line of the forehead at the hair margin. A surgeon re- moved two pieces of the bullet (supposedly all of it), together with some fragments of bone at the wound of entrance, which finally healed. The patient for a time was aphasic, had a left-sided hemi- plegia, and he subsequently developed epilepsy with a peculiar speech aura. An x-nxy plate then showed a foreign body lodged in the left side of the brain near the skull, and just below the middle of the Sylvian fissure. An operation was performed, adhesions due to an absorbed subdural clot were separated, and a small, dense scar, inclosing the main fragment of the bullet, was removed. This had traversed the left frontal lobe, had struck the side of the skull, and ricocheted into its position. The extraction of the bullet benefited him in no respect, and he is progressing to mental degeneracy. Treatment. — The fracture itself is the least of the ills following cranial gunshot wounds and can not be considered apart from the other complications. If there is a clean-cut perforation and no serious immediate symptoms the wound may be left with a simple drain and healing may take place without incident; for luiless septic foreign particles have been carried in with the missile, its track quickly cica- trizes and the bullet itself becomes encapsulated. If there is a lacerated scalp and considerable local comminution of the skull it is advisable, after paring the edges of the scalp wound, to enlarge it by incision and to trephine the skull in order to readjust any de- pressed fragments, to evacuate clots, to relieve tension, and to aiforcl better drainage. A large defect almost always leads to a hernia and perhaps to a fungus cerebri, owing to the swelling of the lacerated brain. Largely owing to this, drainage of the track of the bullet is a most unsatisfactory procedure, and one must usually be satisfied with a superficial drain down to the dura and brain, but not far into the latter. The temptation to probe for, to locate, and to extract deep-lying fragments of the bullet should be resisted by the surgeon ; for even if successful in their object these procedures usually serve merely to increase the damage already done by the missile without conferring any benefit whatever from its removal. The late complications must be met as are those due to cranial injuries from other causes, and here again it must be borne in mind that the paralyses and mental disturbances are not due to the presence 13764—17 2 18 WAR SURGERY OF THE NERVOUS SYSTEM. of the foreign body, but to the cicatricial changes in the nervous tissue due to its passage through them, and that they consequently are the same whether the bullet has lodged, emerged, or been removed. Fractures according to their situation — Fractures of the vault and fractures of the base. — There is a certain justification in this common anatomical division, for in the two situations not only do fractures differ in the mechanism of their production but also in the form which they assume and in the complications to which they are liable. The bones of the exposed vault are more liable to direct, indenting injuries, and hence, despite their greater strength, comminution with dislocation of fragments is frequent; those of the well-protected, though more fragile base, are more subject to Assuring, the result of general deformation of the skull. These, of course, are not invariable rules, for we may have simple fissures of the vault from bursting or a local comminution with depression at the base from bending — an example of which is the not uncommon fracture which occurs about the foramen magnum as the result of falls on the buttock when a direct blow is transmitted to the base through the spinal column. Again, a simple bending fracture of the base may follow a sharp blow on the chin, when the ramus and condyle of the jaw transmit the force to the base — the prize-fighter's fracture. Finally, it is always to be kept in mind that fractures of vault and of base are apt to be associated. Many statistical studies in regard to cranial fractures have been made from time to time ; notable among them is the recent elaborate monograph of Hans Brun, based on 470 cases which in 20 years had been carefully observed in the Cantonal Hospital in Zurich. Occurrence. — In general it may be said that they are injuries oi young adult life ; that they are many times more frequent in men than in women; that in the majority of cases (60 per cent) they are the result of falls from a height. About one-half of these fractures in- volve the base, often alone, sometimes with associated fracturing of the vault. On the other hand, it is estimated that TO to 75 per cent of all fractures of the vault are accompanied by basal injuries. Frac- tures of the vault are more often compound than simple, and they occur with about equal frequency in frontal, parietal, and temporal bones, being rare in the occipital region. Basal fractures are more common in the midcranial fossae. Mortality. — Disregarding the etiological factor, the patient's age. and also the character of the injury, about one-third of all cases in the past have proved fatal, and as the fatalities are largely due to the immediate cerebral complications, modern methods of treatment have not served to greatly alter these figures. The percentage of fatalities increases with age — the younger the individual the more favorable FKACTUEES OF THE SKULL. 19 the outcome. Fractures of the base are coimiionl}' thought to he attended Avith a higher mortality than those of the vault, though with our improved diagnostic measures (lumbar puncture, for ex- ample) we may find that many cases of simple basal fracture have heretofore been overlooked and regarded merely as concussion — a fact which may make one's percentage of recoveries at least appear larger to-da3^ Excluding those cases which have died as an iuunediate result of the injury and those which have later succumbed to infec- tion, the average duration of life in the fatal cases is said to l)e 44 hours; so that there is some basis for the old rule, adhered to by Bergmann and Wagner, that survival over two days gives a favor- able prognosis. Of- the cases which survive the first 48 hours, a considerable num- ber (S per cent of all fatalities) die from the intermediate complica- tions of meningitis or abscess. Fractures of the base are more liable to this complication than those of the vault; for the latter are ac- cessible and easily drained, so that, unless there be a defect leading to a fungus cerebri, dangerous from a persisting leak of cerebrospinal fluid, infection rarely occurs. Basal fractures, on the other hand, especially those which open up the sphenoidal or ethmoidal sinuses where pathogenic organisms lurk, are often followed by a meningeal infection. In this case the pneumococcus is the more common agent, whereas in fractures of the vault a streptococcal or staphylococcal infection is the usual one. I have twice seen a rapidly fatal pneumo- coccal meningitis start up on the third day after what appeared to be a simple, uncomplicated basal fracture with a little bleeding from the nose and so few subjective symptoms that the patients remonstrated at their enforced recumbenc3^ The prognosis is in no way proportionate to the extent of the cranial injury, but depends entirely on the character of the intra- cranial lesions which will be fully considered anon. An insignifi- cant crack of the base, associated" with a focal hemorrhage in pons or medulla, may put a sudden end to life; whereas an extensive fragmentation of the vault, which allows for considerable cerebral expansion, may actually save life through " decompression.-"' An insignificant punctured fracture which does not even produce con- cussion may prove fatal from meningitis or abscess later ^ on ; a conuninuted and depressed compound fracture may, on the one hand, cause death quickly from hemorrhage and compression, or may heal practically untreated and give few symptoms. On the whole the immediate prognosis is more favorable in bending fractures than in bursting fractures; in other words, more favorable in those which are accessible than in those which are not, for it depends largely on the possibility of early treatment not only of the frac- ture, but of its underlying complications. 20 WAR SUKGEBY OF THE NEEVOUS SYSTEM. The diagnosis of fractures of the vault may offer clifHculties, par- ticularly in the case of linear fissures and of those involving the inner table alone. One, however, is much more apt to be misled by the jjeculiar feel of the infiltrated edge of a subaponeurotic extra- vasation into making a faulty diagnosis than to overlook a cranial fracture when it is actually present. When the scalp is intact, linear fractures may at times be recognized through lines of ten- derness on pressure, particularly over the temporal fossa, and by a changed percussion note if there is any gaping of the fissure. In open wounds there should be no difficulty in recognizing even a closel}^ approximated fissure, owing to the blood which oozes from between its edges; sutures, however, may be mistaken for fissures. Localizing cerebral symptoms, to be discussed later, are often help- ful in determining the situation of a depression if it is not actually palpable, and involvement of cerebral nerves may indicate the direc- tion taken by a meridional fissure. Old deformities dating from birth, patches of senile atrophy, defects from former diseases, like syphilitic osteomyelitis, and the irregularities present in all skulls, though more marked in some, may at times be mistaken for depression. In fractures involving the base alone we must, in the long run. depend entirely upon the symptoms which we have learned to recog- nize as common accompaniments of these injuries, rather than upon any direct evidence of the bony lesion. Evidence from intracranial or extracranial bleeding, either free or into the tissues, is of partic- ular value. The intracranial extravasations usually take place into the sub- dural space, for, owing to its close attachment, the dura is usually torn when the bones are fissured. The amount may be small or so extensive as to cause rapidly fatal compression. It ma^^ be recog- nized by finding evenly distributed red blood corpuscles in the cere- brospinal fluid withdrawn from the lumbar meninges. The extracranial extravasations may also be free and bleeding may occur from the nose, mouth, or ears, in case the ethmoid, the accessory sinuses, the Eustachian tube, or the tympanic cavity have been impli- cated. It is necessary to exclude a simple " bloody nose," rupture of the tympanum, or entry of blood from Avithout into the auditory canal. Extravasations into the tissues (ecchymoses) appear more tardily. They are common in the orbit, under the eyelids or con- junctiva when the frontal plate is injured, and in fractures of the middle or posterior fossae they find their way to the surface over the mastoid process or down the neck after some days. The escape of cerebrospinal fluid often occurs with fractures enter- ing the middle fossa, particularly when they involve the petrous bone and when both dura and tympanum have been torn. The escape FKACTUKES OF THE SKULL. ^ 21 of bloody fluid may continue for days and the symptom need not always be entirely undesii-able. as pressure may be relieved thereby. Open fractures which conmiunicate with the nasal or pharyngeal cavities may likewise be followed by a leakage of cerebrospinal fluid, though it is less common from these situations. In rare cases, after a lesion of the petrous bone unaccompanied by rupture of the tym- panic membrane, fluid may escape into the pharynx by way of the Eustachian tube and either be swallowed or flow from one nostril when the head is tilted down. The complications of cranial fractures often ser\'e as an aid in diagnosis. They are estimated to occur in 46 per cent of fractures of the vault and in 64 per cent of those of the base. Varying grades of concussion, contusion, or compression are almost inevitable: only exceptional forms of fracture occur without one or another of these classical symptoms, though any one of them may result from an injury in the absence of fracture. They are apt to be more outspoken in basal lesions, owing to the diffuse character of the blow necessary to produce a bursting fracture. As will be described in its proper section, compression may be general or local, and when local it may give cerebral symptoms of irritation or of paralysis, which serve to point out the situation and character of the cranial lesion. This is often the case with indented fractures of the vault which lead to cortical laceration of the brain, or with meridional fissures which cross the meningeal groove and lead to extradural hemorrhages with their characteristic " interval " between symptoms. These extradural hemorrhages can only occur under the vault where the dura is more easily separable from the bone than at the base; and it is to be re- membered that they are not necessarily an indication of fracture, but may be the result of simple deformation not sufficient to break an elastic skull. Involvement of the cerebral nerves may prove a valuable diagnostic aid. The facial is by far the most commonly injured, owing to its devious course through the petrous process, so frequently implicated in fissures entering the middle fossa. The mere presence of hemi- tacial palsy, however, after an injury to the head need not indicate with certainty the peripheral involvement of the nerve, for it may be due to a contralateral central lesion. In order of frequenc}'' the ab- ducens comes after the facial, and diplopia from an involvement of any or all of the oculomotor nerves may be the result of breaks in the neighborhood of the sphenoidal fissure. In fissures crossing the frontal fossa? the olfactory often suffers. The optic may be affected i)y direct injury, and lesions of the trigeminus, glossojDharvngeal. v'agus, spinal accessory, and h^'jDOglossal have been recorded. The nerves are apt to be affected in gi'oups, the se\'enth, eighth, and sixtii together; the fifth and third; or the ninth, tenth, and eleventh. The 22 WAR SURGERY OF THE KERVOUS SYSTEM. le.-ions usuall}- occur at or near their foramina of exit, cine cither to actual laceration or to local compression from effused blood; and hence a stud}' of the paralyses may indicate the fossa which the f rac- tnre has entered, Avhether anterior, middle, or posterior. iSerious complications from hemorrhage maj^ follow injuries to Mood vessels, particularly Avhen the sinuses or meningeal artery are lacerated, and occasionally linear fractures crossing the middle fossa toAvard the pituitary fossa may so traumatize the cavernous sinus and carotid as to produce an arteriovenous aneurysm with pulsating exophthalmos. The sequels heretofore considered are common to all lesions of the skull; those due to an infection are almost without exception limited to open fractures, whether of base or vault. In them purulent cellu- litis, osteomyelitis, septic sinus thrombosis, meningitis, or cerebral abscess were formerh' almost to be expected. Modern methods have largely Jessened these evils in the case of the vault, even if not in basal lesions. An insignificant fissure which passes across the ethmoid plate may open a pathwav of infection from the nasal cavity and lead to a rapidly fatal meningitis. Cerebral abscess is especially common after ]5unctured or gunshot wounds from the deep inoculation of in- fective agents, though it occurs often enough in compound commi- nuted fractures which have led merely to a superficial laceration of rhe cortex. Barer complications, like spurious meningocele, pneumatocele, and others too numerous to mention, may llkevN'ise occur. Cysts occasion- ally form after fractures either from a torn dura, from the parti;il absorption of a clot in the subdural space, or from a subcortical extravasation. vSugar may appear in the urine (traumatic glycosu- ria), usually about 8 to 12 hours after the injury and in about f) per cent of all cases, according to Higgins and Ogden. All of these, as well as the so-called post-traumatic neuroses, result from the cerebral, not from the cranial injury. The ■process of healing does not take place as in the long bones, where there is an abundant callus formation. Dura and periosteum, however, are both capable of forming neAv bone, as we have seen in ex'^stoses, osteophytes, etc., and complete repair, even when there has been a loss of substance, may occur. It may, however, l^e long de- layed or completely fail, due, according to Bergmann, to the de- struction or less of the osteoplastic layer of both inner and outer periosteum as well as to the absence of movement which ordinarily stimulates callus formation. Union often occurs by fibrous membrane alone; even narrow fis- sures may fail to become reunited b}- bone. As a rule, however, a slow process of bone production and bone absorption goes on, hand in FEAOTURES OF THE SKITLI,. 23 hand, and irregular edges or depressed fragments are rounded off as the gaps are more or less filled in. Occasionally there is an over- production of new bone, leading to focal or to widespread hyperos- toses from either the outer or inner table. Even defects of some size may at times become entirely ossified, and even when closed by mem- brane alone they may become so firm and inelastic as to show no pul- sation. According to Bergmann, defects can not be expected to close if the}^ exceed a diameter of (5 to 8 centimeters, and it would indeed seems that it is rare even for much smaller openings to fill in. There is a great difference of opinion as to the injnrious effect of these bone defects, some holding the view that when extensive they lead, in the course of time, to serious mental symptoms. Personally 1 do not believe that they are injurious unless accompanied by an underlying lesion of the dura. When the dura is wounded and the scar formation leads to adhesions between overlying scalp and brain, the chronic fibrous changes which result may lead in time to ex- tensive cortical alterations and mental deterioration. With an in- tact dura, however, such symptoms are less likely to occur. Treatmient. — We are confronted again by the necessity of distin- guishing between the management of the fracture itself and the man- agement of its complications. Relatively, simple rules can be laid down for the former ; for the latter our conduct is largely controlled b_y physiological laws relating to the circulation of the blood and cere- brospinal fluid under abnormal conditions. In fractures of the vault the indication for surgical intervention is usually deformation of fragments, rather than critical cerebral complications; in fractures of the base it is the reverse, for there intracranial complications are especially serious and deformation is rare. In compound injuries of the vault we may easily determine the form and estimate the consequences of the injurj^, and our endeavor should be to thoroughly cleanse the wound, to elevate depressed fragments, to restore a wound in the dura if one exists, and to leave the parts as nearly in their natural position as possible. If the fragments are depressed and wedged it may be necessary to trephine at the edge of the depression before they can be pried into place. Even in the ab- sence of visible depression an opening may be required when cerebral symptoms are present, due to depression from the inner table alone or to intracranial hemorrhage. It is another matter when injuries of the vault are covered by intact scalp, for there maj^ often be great difficulty in determining whether there is sufficient justification to transform a simple into a compound fracture, even for the sake of determining the lesion. It is largely a personal matter and rests with the judgment of the oper- ator; and this in turn depends entirely upon his familiarity with intracranial disturbances which are amenable to operative treatment 24 WAR SURGERY OP THE NERVOUS SYSTEM. and his ability to safely cope with them when found. A simple fissure, which crosses the temporal region, of itself needs no surgical interA^ention, but this is urgently called for when pressure symptoms indicate either a lesion of the meningeal or free extravasation at the base. When simple fractures are accompanied by evident depression surgical measures are indicated, even in the absence of immediate cerebral symptoms, for unelevated fragments are almost certain to be the source of future trouble, especially if the dura has been in- jured. The opening must be carefully examined on all sides, for de- pressed fragments are readily overlooked. In Fig. 50 is shown a pa- tient with a depressed fracture which had solidly healed, in so far as the union of the displaced fragments was concerned, and the rounding' off of their sharp edges, and yet serious mental (left frontal lobe) symptoms resulted. In an old healed depression of this sort it is necessary to remove the entire area by a circular incision and either to leave a defect, to replace it by some foreign material, or to cover it by an osteoplastic flap. Occasionally the cup-shaped area may be replaced inverted without subsequent necrosis. When there is extensive comminution with many lose fragments it may be difficult to determine whether any of them should be re- moved, owing to possible loss of viability. The dread of necrosis and of infection, though a natural one, is largely an inheritance from our surgical forefathers, and it is a matter of present-day experience to find that fragments of surprising size, even when completely sep- arated, will survive if left in a clean wound. It formerly was the custom to remove all completely detached pieces. It has been learned, however, that even boiled fragments may heal after reinsertion. I have quite frequently rejjlaced a 3-cm. trephine button after boiling it (owing to some suspicion of its perfect cleanliness), and have never seen it fail to heal in place ; it is well known, of course, that an unboiled fragment of this size can always be safely replaced. In the latter case it is probable that bone-forming cells of either surface or of the diploe may remain viable, but in the former instance they have been destroyed and it is to be presumed that the fragment acts only as a temporary stimulus for new^ tissue, becoming itself ulti- mately absorbed. The queston of closure of defects will be consid- ered later. The treatment of basal fractures resolves itself largely into the treatment of contusion or compression of varying degrees, for which our therapy is largely restricted to rest, absolute quiet, an ice cap,, sedatives when headache is severe or when there is great restlessn^'ss, and to free evacuation of the bowels, preferably with a saline — measures to be observed in practically all cases of cranial injury. The greatest care should always be exercised in handling and in trans- FRACTURES OF THE SKULL. 25 porting any case of fractiu-e witli intrat^ranial syniptoiiis. for the symptoms are much aggravated by any form of jolting. With the view of preventing infection in case there is bleeding or loss of cerebro.^pinal fluid from the nose or ears, it is customary to irrigate and tamponade the auditory meatus or the nasal chamber. This procedure, however, can be overdone, and only in case the hem- orrhage is profuse is it justifiable to actually pack these orifices, for nothing is more certain to set up a suppurative infection of the mucous membrane. Irrigation of the nose or of the ear to remove clotted blood and to cleanse the cavities has an element of danger, and it is preferable to accomplish this by merely wiping out the passages with a sterile cotton swab moistened in a mild antiseptic solution. It is important not to irrigate the kSchneiderian mem- brane in such a way as to produce a sneeze, for on more than one occasion this has been disastrous and the explosive effect has driven septic material into the middle ear or ethmoidal cells and appar- ently has been the active agent in inaugurating a septic meningitis, After cleansing, the cavities should be loosely closed by a wisp of absorbent cotton, or of iodoform gauze if desired, which will serve to take up the secretions and which should be frequently changed if there is abundant discharge. Although by energetic measures we rasLj overcome a local meningeal infection which has started over the hemisphere, we stand practically helpless before one originating at the base, although suboccipital drainage in a few cases has apparently resulted in cure. One can speak somewhat more encouragingly in regard to active interference in case of diffuse hemorrhage. The fatalities from this cause, as will be detailed in the section dealing with compression, are due to a final implication of the vital centers in the medulla when the amount of effused blood is sufficient to so increase intracranial tension that they are thrown out of function from anemia. Though this has been Avell recognized, operative methods of meeting the situation have been inefficient or untried, owing to the feeling of hopelessness in the presence of continual oozing from an inaccessible and often uncertain lesion. Exploratorj^ openings have usually been made over the vault, but, owing to the increased cerebral tension, such openings become filled with a bulging brain, drainage can not be effective, and a fungus cerebri is often produced. It is self-evident that an opening as near the lesion as possible is desirable, and, inasmuch as most of these fractures enter the middle fossa, an opening low down in the temporal region is most likely to be efficacious. The author's procedure, which has been designated as an intermusculotemporal operation, often meets the needs of the condition. In this o]Deration, by splitting the temporal 26 WAR SURGERY OF THE NERVOUS SYSTEM. muscle in line of its fibers and by rongeuring away the thin squamous wing of temporal and adjoining sphenoid, not only is the region over- lying the meningeal vessels exposed, so that a chance extradural hem- orrhage can be brought to light, but also the dura over the temporal lobes is exposed and the presence or absence of subdural effusion can be determined. The dura should be opened and there will usually be an abundant escape of bloody cerebrospinal fluid, Avhose evacuation will be aided by passing a curved, blunt dissector down under the temporal lobe. Oftentimes edema, as we have seen, has played the chief role in the compression, and we may find that merelj^ a so-called " serous meningitis " is present, and that evacuation of a large amount of fluid will diminish the tension. In such case the muscle and scalp may be closed, but if there is continuous bleeding it is well to close the muscle only in part and to leave, at its lower angle, a strip of rubber protective, leading under the temporal lobe as a drain. In case the craniectomy on one side alone seems insufficient a bilateral operation may be performed at the same or at a subsequent sitting, for the procedure is simple and not attended by shock. Its advan- tages are due to (1) the frequency of the bony lesion in the middle fossa; (2) the fact that cerebral contusions are especially liable to involve the tip of the temporal lobe; (3) the exposure of the menin- geal territory and ease of determining the presence of an extradural hemorrhage; (4) the possibility of draining through a split muscle rather than directly through the scalp; and (5) the subsequent pro- tective action of the muscle in case a hernia tends to form in conse- quence of traumatic edema. The unilateral or bilateral defect in this situation leads to no complications and no subsequent deformity. Part 2. MENINGES, EPENDYMA, AND BRAIN. MENINGES AND EPENDYMA. Anatomic and physiologic considerations — The pachymeninx and its vessels. — A thorough knowledge of these membranes and the part played in intracranial disease by the fluids which they hold is of pi-ime importance. It is permissible to call attention liere to some ot the more essential points only. The dura carries on its outer surface certain arteries of surgical interest and it incloses the great venous sinuses. The intracranial dura differs from the intraspinal dura in its relation to the inclosing bone; for the latter has a double, the former only a single inner layer of endothelial cells, its outer surface adhering more or less firmly to the skull and having, especially in the young, an active share in the process of bone formation. This attachment is an intimate one, par- ticularly at the base, from portions of which the dura can be separated only with great difficulty. Hence in linear fractures of the base the membrane is almost always torn: in similar fractures of the vault it may often escape injury. One source of its firm adherence is to be found in the sheath-like prolongation of the membrane along the course of the cerebral nerves. Such a sheath is especially marked in the case of the optic nerve — a fact of importance in the etiology of choked disk. OAving to this firm basal attachment extradural hem- orrhages are less likely to occur there than under the vault; this is not an invariable rule, for in certain parts of the middle and posterior fossfe it is readily separable from the bone — a fact which is made use of in exposing the trigeminal nerve and in suboccipital operations. Tlie strength of the clural attachment at the vault is variable ; it in- creases with age, so that the membrane tears in removal; in the young- it clings much more firmly to the growing bone at the sutures than elsewhere. In the newborn, for this reason, an extradural hem- orrhage {^''internal cephalhematoma") may be limited to the inner surface of one bone. As a protection for the brain, the clura, owing to its smooth endo- thelial surface, is of much more importance than the overlying bone. A dural defect is replaced by scar tissue, which of necessity leads to adhesions between the cortical leptomeninges and overlying cranium 27 28 WAR SURGEEY OF THE 1\"ER.V0US SYSTEM. or scalp, as the case luaj'^ be ; a clural wound, the edges of which have been accuratel}^ approximated, shoukl leave no such adhesions, as the edge is quickly united by proliferation of the endothelial cells. The dura is, in a measure, separable by dissection into two layers — an outer and inner — between which structures like the Gasserian gang- lion are inclosed; it furthermore opens to inclose the large sinuses, from the inner edge of which falx and tentorium pass off to parti- tion the cranial space into its three main chambers. These strong membranous partitions play an important part in supporting the hemispheres, and, inasmuch as they can be dislocated but slightly out of their normal position, they have a tendency to limit the pres- sure effects of a local process to the one compartment in which it has originated. This is especially so with the subtentorial compart- ment, for the tent like membrane hung from the posterior edge of the falx is particularly well adapted to support pressure from above and thus protect the important centers of pons and medulla. The dura deserves chief consideration as a carrier of blood vessels. The superior longitudinal s^inus lies slightly to the right of the me- dian line. It increases in its blood-holding capacity as it runs from the ethmoid to the torcular. In its course it changes greatly in form. On cross-section, except during its middle course, it is of a narrow, Avedge shape, the apex of the wedge running down for a considerable distance between the two layers of the falx. During its middle sourse broad expansions {lacuna} laterales or parasinoidal sinuses) pass out between the two clural layers for a distance of from 1.5 to 2.5 cm. over the hemisphere. Into these lateral expansions enter many of the more important of the superior cerebral veins, particu- larly those which ascend in the sulci bounding the paracentral convo- lutions, and from them emissary vessels pass through the inner table to communicate with the diploetic vessels. Into the lacuna, laterales project the majority of those bodies known as Pacchionian granulations. They seem to be an acquire- ment of adult life and their function, if they possess any, is uncer- tain. They consist of tuftlike processes from the arachnoid con- taining cerebrospinal fluid; and, covered merely by a thinned-out layer of clural endothelium, the}^ project into and are bathed in the blood of the sinus. As they enlarge they may even project through the lateral expansion of the sinus and cause, through pressure, atrophic depressions of varying size in the under surface of the skull. It is for these reasons that injuries to the skull in this situa- tion or efforts to operate there are especially likely to be attended by hemorrhage; for the calvarium cannot be separated from the dura without tearing the emissary veins or injuring the thinned-out layers of the dura covering the granulations. Furthermore, the dura itself can not be elevated from the brain without injury to the cerebral MENINfiKS, KPEISIDYMA, AND I3HAIN. 29 veins, whicli, as well as the Piicchioniaii gTaniilatioiis, serve to bind it, to the c;ortex. Since the lacunie laterales are sufficiently broad to cover the motor centers for the lower extremities, it is evident that these centers are difficult of access. Owing to the lacunie also, liga- tion of this sinus in its middle course is almost impossible. The longi- tudinal sinus and its expansions, furthermore, are honeycombed by fibrous bands {chor