No. 3362.

FEBRUARY 4, 1888.

Lectures ON

CRANIAL SURGERY.Delivered to the Class of Operative Surgery in the University

of Edinburgh,

BY ARTHUR W. HARE, M.B., F.R.C.S.E., &c.,SENIOR DEMONSTRATOR OF SURGERY, EDINBURGH UNIVERSITY.

LECTURE I.

GENTLEMEN,—In treating of so large a subject in a seriesof four lectures, it is necessary that there should be a con-siderable concentration of each of the topics that presentsitself for consideration, and such an arrangement of each inits appropriate order as may give due sequence of thoughtin traversing the whole field of our inquiry. I shall there-fore adopt the following method of dealing with the subject.First, a short résumé must be given of the architecturalanatomy and the physiology of the skull, coupled with areference to the physics of the skull and its contents;following closely on this comes the consideration of thebehaviour of the skull and its contents under the action ofexternal violence, and of the light thus thrown on thecausation and delimitation of fractures; the corticalgeography of the brain in relation to localised functions,and the relation of certain districts of the cortex to thesurface of the head, must then be considered ; and, lastly,from the data supplied by the preceding inquiries we shallbe in a position to formulate the laws which must governsurgical treatment in the various circumstances that maybring this region under the special charge of the practicalsurgeon.

1. THE ANATOMY AND PHYSIOLOGY OF THE SKULL.For the practical aims here firmly held in view, a re-

capitulation of anatomical details is beside the mark; itremains, rather, to inquire what are the architectural pecu-liarities of the skull which alike indicate and carry out itsessential functions, and in what manner these functions areperformed. In general terms, it may be stated that thefunctions of the cranium are to contain, support, andprotect the tissues of the brain and its immediate appendages.Specially does it interest us to inquire how the last of thesethree is performed, and the answer to this will be found ina careful study of the features of the protective structureitself. Hilton looks upon it as an

11 indisputable fact thatnothing in the cranium exists unless designed to carry outsome definite intention, or unless formed in reference tosome distinct and special object."Before describing these special features of the cranium, it

is well to analyse somewhat more closely in what its pro-tective function mainly consists, so that an interpretationof individual structural peculiarities may be at once at-

tempted in terms of the general function attributed to thewhole. The chief intention, realised in the skull, is to pro-

tect the brain from the direct action of physical vibrations,those vibrations travelling almost exclusively in two direc-tions-viz., from above downwards and from below upwards;the former due to blows on the head, the latter derived fromthe oscillations incidant to bodily movements. Both seriesof forces are directly referable to the erect posture of manand the ordinary conditions of his life; they are thereforenormal elements in the balance of the human economy, and forthem a normal accommodation of structure may be antict-pated. Keeping this in mind, I must now draw attention tothe structure ot the skull. (Fig. 1.) It is an ovoid bony casketof varying thickness and strength in its several parts, but, inthe adult at least, of uniform continuity of structure through-out, for it is only in the child that the sutures have any func-tional significance. It is an irregular spheroid consisting of anupper dome-like portion or vault, and a lower plate-like partof irregular contour, forming the base. Nbt only do thesecomponent parts differ in shape, but also in inherent strengthand in elasticity; for, while considerable alterations in formare possible in the resilient vault under the action of com-

pressing agencies, such forces cause great commotion in theregion of the base, which is relatively brittle and inelastic.It is specially as regards its conduct in relation to vibra-tions that this difference is of importance, for while theupper portion is able to vibrate as a whole, and to dis-tribute vibrations equally in all directions throughout itsstructure, the same does not hold true of the lower portion,whose irregular form will give rise to discontinuity in thelines of transmission of force at many points, and notablyat the circumferential borders of the base, where theascending walls of the vault are united with it. In a word,the vault is constructed to distribute vibrations in everydirection, and thus to avoid the effects of concentratedoscillations at any part; the base is not prepared for sogeneralised a function, nor is it requisite in ordinary eon-ditions that it should be. It has, however, ample provisionfor transmitting vibrations in the normal directions alreadydefined-viz., from below upwards, and from above down-wards, by the following mechanism. The skull is provided

Fin. 1.

The arrow shows the direction of the force applied;a indicates the isolated fracture of the base. There wasno fissure of the vault in this case.

internally with a series of thickened buttresses or costse,evident in the vault, but most clearly to be traced as theycross the region of the base. The ridges may be dividedinto three main systems, which pass downwards from thevault and converge to a point in the base, which has beentermed by Felizet the " centre of resistance." The anteriorseries is gathered into the lesser wing of the sphenoid, andterminates on either side in the anterior clinoid process.The middle group, collected into the petrous portion of thetemporal bone, passes to the centre of the base of the skull,and terminates at the foramen lacerum medium. The

ridges of the posterior group, meeting at the torcularHerophili, pass forwards to the foramen magnum, at theposterior limit of which they divide and pass forward tomeet again in the basilar process, and they ultimatelyend in the posterior clinoid procssses of the sphenoid.The point that has been termed the "centre of resist-ance" is situated in the region of the sella turcica;it is provided with quite an unusual combination ofphysical conditions, which I must more closely describe.

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In so doing I cannot do better than quote the wordsof John Hilton, from whose Lectures on the CraniumI have chiefly summarised the preceding anatomicaldescription. He says: "The anterior clinoid processes liesurrounded by cerebro-spinal fluid, without having, as Ihave already said, the slightest degree of connexion withthe superimposed brain. And the vibrations conducted tothese points become here broken or lost in this fluid, whichthereby intercepts their transmission to the tissue of thecerebral organ. The petrous portions of the temporalbones, being separated from the basilar process by an inter-vening layer of soft or membranous structure, the vibrationsconducted in this direction become here also completelyobstructed without transmission to the base....... Some,passing by the dense ridge of bone that extends fromthe occipital condyle to the jugular process, reach thepetrous portion of the temporal bone, whence they areconducted to its extremity, where they terminate in thestructure already referred to; others, travelling along thebasilar process of the occipital and sphenoid, arrive at theposterior clinoid processes, where they are intercepted orlost in the cerebro-spinal fluid, which surrounds these aswell as the anterior processes." In this way the vibrations,travelling from above downwards, are annulled by transfer-ence to fluid or soft solid, through which they pass in everydirection, losing any dangerous degree of concentration andfailing to affect the cerebral structures. In regard to thevibrations, travelling in an opposite direction, they are com-municated to the base of the skull through the spinal column.At the region of the foramen magnum they divide into twoseries, some, passing forwards through the basi-sphenoid,traverse the middle set of ridges from below upwards andlose themselves in the resilient vault; others follow theposterior ridges back to the torcular, where they are furtherdivided and in their turn reach the vault, where they arefinally disseminated. It is in virtue of this special arrange-ment that we are normally unconscious of the constantjarring that must be present in the ordinary course ofphysical exercises, and to how large a degree we are

indebted to them may be judged of by a comparison ofthe results of force applied in normal and in unusualdirections to the skull, the former producing no evidentresults, the latter giving rise not unfrequently to very graveconsequences. The absolute importance of this mechanismdepends upon the physical arrangements of the skull andits contents. Here we find a closed rigid system, in whicha rapid increase of tension is fraught with great danger,and in which the only natural safety-valve, that suppliedby the continuity of the spinal canal, is inadequate tomeet the requirements of a sudden emergency. Anydriving in of a portion of the brain-case is therefore themost untoward event that can happen in such a system,and in the series of buttresses already described we mustrecognise a great safeguard against such occurrences.

These ridges, although they take in many cases an

irregular course, still may be distinctly traced intheir convergence towards the base; and, in virtue of theirgreater thickness and solidity, they tend specially to collectthe cranial vibrations, and to transfer them to the centre ofresistance on the one hand, or to the vault on the other,where they are annulled, as has been already mentioned.From this it follows that these are really the strongest partsof the cranium, for they can most easily get rid of excessivevibrations communicated to them without suffering solutionof their continuity; on the other hand, the parts betweenthese buttresses. which have not the same facility, are muchmore liable to the unmodified results of forces applied tothem, and practically they are found to be the more frequentseat of cranial fractures.Having thus defined the architectural arrangements of the

skull and the functions they are suited to perform, let usinquire into the behaviour of the skull under the influenceof external forces applied to its various regions. ,

2. THE ETIOLOGY OF FRACTURES OF THE SKULL.

In the first place, we must discuss the varieties of forcethat may be brought to bear upon the skull, since they areimportant factors in the production of one or other of avariety of results. It is not as regards the amount of forceapplied that I would claim any essential difference to holdtrue; for the same laws govern larger and smaller forcesalike, and thus a proposed division of fractures by Félizetinto those due to great and those due to slight violence mustbe at once dismissed as purely artificial; but it is rather

as concerns the way in which these forces are applied thatthese differences hold true; and I think we shall observethat an essentially different practical result occurs on theapplication of a diffuse blow from that produced by onethat is concentrated in its area of application. The con-centrated blow produces local effects only on the skull inthe great majority of cases, as seen in bullet wounds orsword cuts. This applies to all parts of the skull alike,without reference to regional differences of form, and isexemplified in the region of the base by those fractures wherethe condyle of the lower jaw is driven through it, or woereviolent shocks are transmitted toit through the spinal column,resulting in a circular fracture around the foramen magnum-i.e., one localised to the point of application of the taree.On the other hand, in a diffuse blow there is less tendencyto fracture at the immediate seat of its application than atsome distant point, and practically we find that lesions dueto this form of violence are more often characterised byremote than by local effects. It is, therefore, to the actionof diffuse blows upon the skull that we must turn forevidence as to the influence of its special structure upon theform and direction of the resulting fracture. Enough hasalready been said upon the structural difference betweenthe vault and the base to make the earliest of themodern theories of fracture unlikely, and a very slightacquaintance with the facts renders it quite untenable.That theory depended on the law of "contre-coup," whichobtains in the case of apheres of uniform strength and ofregular structure, but could scarcely apply to such astructure as the kull. It was promulgated by Saucerotte,who maintained that the vibrations set up by a blow travelin all directions through the walls of the cranium, and areconcentrated to a focus at the opposite pole of the skullfrom that struck, at which point a stellate fractureis produced. This theory seemed to accord with thesignificance of some points in the anatomy of thecranium, but it is with some surprise that I find that Hiltonbelieved in it, in view of the innumerable cases inwhich there is no polar relation between the point ofincidence of a blow and the point of fracture. It hasnow been largely abandoned, chiefly owing to theresearches of Aran, who, as the result of experiment, cameto the conclusion that fractures of the base occur by theradiation of fissures from the point of application of theforce. The fissures pass by the nearest route to the base,and involve it in the fracture. Félizet also agrees generallyin these views, but finds in the majority of cases that thefissures, instead of taking the nearest route to the base,pass downwards in the intervals between the bonybuttresses described by Hilton, where there is a greatertendency to fracture than in the costse themselves. Thesetwo theories-the vibratory, or theory of " contre-eoup,"and the radiation theory of Aran, struggled long for preeminence ; and this contest was the occasion of much experi-mentation intended to throw light on the question. It hadbeen observed by Aran that in numerous cases the position ofthe chief fracture of the base was far removed from theantipodes of the point where the force was applied. He

accordingly investigated the matter, and the followingsummary of his experiments by Sir Prescott Hewett inHolmes’s " System" so well describes them and their resultsthat I quote it without apology: " In precipitating a largenumber of bodies from various heights on to the head,Dr. Aran found that the part of the vault which first struckthe ground gave, as it were, the key to the fracture whichwould take place at the base. Similar results were also ob-tained when diffused blows were dealt upon different parts ofthe skull by means of a large and heavy hammer. In the frontpart of the vault injuries thus produced led to a fracture ofthe anterior fossa, in the middle part of the vault they led to afracture of the middle fossa, and at the back of the head toa fracture of the posterior fossa. In no single instance wasa fracture of the base detected without a line of fracture inthe corresponding part of the vault." Sir Prescott Hewettgives his entire allegiance to Aran’s views, and confirms themby a summary of the cases at St. George’s Hospital whichhave come under his notice.

It is true that this theory, based as it is upon both ex-periment and practical experience, seems at first sight topreclude any further discussion of the matter; but thereare certain series of more recent experiments whose resultsseem to throw some doubt on Aran’s theory, and upon themhas been based another theory which appears at least equallywell to explain the actual appearances in such cases. In

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í872 SJhwarz published the results of a series of experimentson the heads of cadavera, in which he found that on theapplication of force to the side of the skull fracture of thebase constantly occurred in the middle fossa, and in a direc-tion parallel to the petrous portion of the temporal bone, andthus parallel to the line of the force producing it. Similarly,if the force be applied to the frontal or occipital region,the resulting fracture occurs in the longitudinal axisof the base; and if in the mastoid region, the fracturetraverses the base diagonally. In other words, in eachcase the line of fracture is parallel to the line of force. Theseresults, after remaining comparatively unnoticed for severalyears, were put to the test in 1880 by Meserer, and in 1881by Hermann, and in both cases substantially the same resultshave been arrived at. The former expresses his opinion asfollows : "That fractures of the base always occur in thedirection of the force applied, or at any rate parallel to it,and thus are not looked upon as the result of radiation,but of compression or bursting." " In illustration ofthis view, he makes use of the following example:" If a hollow sphere be subjected to pressure, the breakageeither occurs immediately at the point of pressure, or I

by bursting at the most distended part." Thus infracture of the skull due to diffuse blows one or other ofthese forms of fracture will occur-the former illustrated,he thinks, by circular fractures around the foramen magnumfrom the spinal column being impelled upwards, and thelatter in any fracture of the base from indirect violence.Von Wahl, adopting Meserer’s views, makes use of the

accompanying diagram to explain this point. (See Fig. 2.)

Fit. 2.

Let A BCD be a hollow elastic sphere, and let it be com-pressed at the poles A and c until it takes the form ef g h.If its elasticity be equal in all parts, the first breach of con-tinuity may occur at any point on the equator aroundwhich the tension is greatest; and when it does happen, itwill have the direction of one of the meridians of the sphere,stretching towards both poles, as represented by the broadblack line in the diagram. Supposing one segment of thesphere, however, to be less elastic than the others, itwill be at once singled out on that account as the seat ofthe first breakage which occurs, and the line of breakage willpass in the same direction as before-namely, parallel to theline of the force producing it. The application of theseremarks to the case of the human skull is obvious, and weare the more prepared to acknowledge their force, as wehave already noticed how much the inferior segment of theskull is lacking in elasticity as compared with the superiorsegment. We should thus be led to expect that if like con-ditions be applied to the skull a like result will follow-viz ,a fracture parallel to the line of force, commencing at theequatorial part of the base and spreading towards eitherpole. If we now turn to Hermann’s experiments we findthis actually carried into effect. He found that by applyinggradual increments of force one could watch the fracturedevelop itself, commencing, as it always did, in whatrepresented the equatorial zone of the base-i.e., midwaybetween the points of pressure-and extending as more

force was applied in both directions parallel to the line offorce towards the poles, at which it was applied, untilhe had obtained exactly the same appearances as thoseupon which Aran based his radiation theory-viz., thatfrom one of the points of application of the force a fissureran towards the base and involved it. In this way Hermannattempts to prove that the appearances produced in Aran’sexperiments were due to the excessive amount of force used,

which first shattered the base, and then led to the formationof the radiating fissure leading to the point of the applicationof violence. Von Wahl, in his pamphlet, accepts this view,and figures sixteen cases of fractured base from the SurgicalMuseum of the University of Dorpat, each accompanied byshort notes of the case, which in the main bear out hisviews. He specially draws attention to one, which canhardly be explained on the radiation theory, as there arefissured fractures of the base quite isolated, having noradiating fissure in connexion with them, passing towardsthe point of application of the force ; although in this casethe history points to conditions exactly similar to thoseused by Aran in producing his experimental results-viz., afall from a height upon the left frontal region.

I have within the last twelve months had a similar casein my own practice, in which a blow on the lateral frontalregion was followed by symptoms suggesting fracture ofthe base. In this case I ventured to diagnose a fissuredfracture, and defined its direction in terms of the law justmentioned. A month after the accident the diagnosis wasconfirmed by a post-mortem inspection, and an isolated basalfissure was discovered, involving the anterior and middlefossae, but with no prolongation to the part of the vaultstruck. This is illustrated by the accompanying drawing(Fig. 2), taken at the time by Mr. W. A. Scott, M.A. I con-sider, therefore, that we must adopt the views of von Wahl,that the fracture occurs in the line in which the force isapplied or parallel to it. This, however, with certainreservations; for the experiments of Meserer and Hermanndid not extend to an investigation of the remote effects onthe base from injury to the vault; and it is only inthe case of forces applied to the lowest segment of thevault, or more properly to the edges of the base, thatthe theory of parallel cleavage is found to hold true.The holding of this theory in no way detracts from thevalue of Aran’s experiments; it accepts and appropriateshis results, but slightly modifies his interpretation ofcertain of them. This modification would be a trivialitywere it not for the important clinical issues involved, for ifwe can by applying the law of parallel cleavage define thecourse of cranial lesions, much has been done towards re-moving that uncertainty which is the great bar to logicaland successful treatment. To sum up, then, my views ofthe results of diffuse blows on the skull in a few words:Diffuse blows produce their chief effect at a distance fromthe point of their application; those struck on the vaultproduce fissured fractures in the corresponding segment ofthe base; those struck on the periphery of the base pro-duce fissured fractures on the base of the skull parallelto the direction of the force applied.

ABSTRACT OF

The Lettsomian Lectures ON

SOME POINTS IN THE SURGERY OF THEURINARY ORGANS.

Delivered before the Medical Society of London,BY REGINALD HARRISON, F.R.C.S.,

SURGEON TO THE LIVERPOOL ROYAL INFIRMARY, AND LECTURER ONCLINICAL SURGERY IN THE VICTORIA UNIVERSITY.

LECTURE III.

The operative treatment of stone and tumours of the bladderin relation to some recent views and practices.

MR. PRESIDENT AND FELLOws,-The surgery of thebladder during the last ten years will under all circum-stances occupy a conspicuous position in the history of ourart by the introduction of litholapaxy, the revival of thesupra-pubic or high operation under somewhat alteredconditions, and by an approach to a somewhat more

systematic method of treating tumours connected with theinterior of the viscus. A vast amount of experience hasalready been obtained bearing upon these various measures,and I think the time this evening cannot be better occupiedthan in drawing some conclusions in regard to them, which,