On the veins of the diploë

70 THE BRITISH JOURNAL O F SURGERY

ON THE VEINS OF THE DIPLOE. BY GEOE’FRET JEFl4’ERSON,

HONORARY NEUROLOGICAL SURGEON T O T H E MANCHESTER ROYAL INFIR3IARY ; HONOR.4RY SURGEON TO T H E SALFORD ROYAL l i O S P I T A L ;

AND D. STEWART, L I X T U R E R IN AXATOXY I N T H E UNIVEItSITY O F MANCKESTER.

THE existcnce of venous channels in the interior of the various bones of the human skeleton is to-day so widely, so universally recognized, t h a t i t scenis strange that any era of anatomical knowledge can have existed when men went in ignorance of tlicni. That the bones were well supidied with blood was certainly known, as the opcration of amputation must have early taught the surgeon-anatomist. But that there wcre definite venous channels, that ordered systems existed in the interior of the bone, and particularly that these were present in tlic diplot; and vcrtebrz, were certainly unknown until the earliest years of the nineteenth century.

I n the year 1803 Dupuytren published in Paris a small monograph the first chapter of which is entitled “ Canaus Veineux dcs 0s.” In this scctioii he speaks of the little-known veins of the cliplot; as difficult or impossible to inject, but possible of display by section of the bone (as in the rertebrz) or by chiselling away the compact outer layer (as in the skull). Dupuytren gave a brief summary of the diploic vcins. stating that there are three or four channels in thc bone on each side draining from the summit downwards, and emptying into three sets of veins, nainely, the external vcins, the veins accompanying the meningeal arteries, and the nieiiiiigeal sinuses of the cranial base. There is very little detail, and it is evident that Dupuytren is satisfied to be placing on record the bare outline of a ncwly discovercd fact.

Here the matter rested until four years later, when Chaussier took up the anatomy of the diploic veins anew in his book (E’trposition sommaiie de la Structur.e et des d i f 6 r m t s Pnrties de I’EwLphnle 011. Cerzmm). This author gives an adiiiirable description of the vesscls, and accompanies i t with a single clear explanatory plate. But lie makes no mention of Dupuytren, and, indeed, so far is he from crediting Dupuytren with their discovery that he states on p. 18 of his prcfact that the diploic 1-eins “ hare been discovered by M. Fleurp, prosector of the Ecole dc MCdecine, and now doctor and surgeon-in-chief of the Hospital of Clermon-Ferrant.” These bibliographical points are interest- ing and rather confusing, and our confusion is increased when we find that anatomical test-books to-day almost all attribut,e the veins to yet another person, the distinguished French anatomist Gilbert Bresehet. It was not until 1819 that anything on these veins came from Breschet’s pen, the first of a series of three papers, each of increasing importance, and culniinating

THE VEINS OF THE DIPLOE 71

in the magnificent volume of studies which bcgan to appear in 1830 and was never completed. The solution of the problem as to priority is to be found in a paper by Raciborski, “ Histoire des Dkcouvertes relatives au SystCme Veineux,” 1536, from which we gather that Cliaussier was indeed correct when he attributed the discovery of the veins to Fleury. Raciborski refers the reader to a letter written by Fleury to the Gazette JILddicaZe in 1836 in which Fleury statcs that he found the diploic wins by chance whilst preparing skulls for the museum. He removed the outer table to exhibit the diploe, but going a little deeper than usual came across the venous channels. He told this fact t o his intimate frienfi Dupuytren, who made i t the subject of a memoir read to the Socikti: de 1’Ecole de Mkdecine, and later included i t in the thesis of 1803 to which reference has already been made. Raciborski remarks, ’‘ If we regard Dupuytrcn as the first of thc authors who have spoken of these venous channels in the bone, we ought always to render justice to If. Fleury and regard him as the author of this discovery.” He refers also to the enmity

FIG. 47.--Thc frontal diploic veina. Noto t.hcir emergence at the well-known cmissary foramen in the supra-orbital rnargin (Breschet).


THE VEINS OF THE DIPLOG 73

3 c:


FIG. 50. -To show the dispositions of the occipital diploic veins, coinmnnicating Xvith the posterior temporals or parietal veins (Breschet) .

between Chaussier and Dupuytren, whenre the omission of any reference by the former to the early paper on the ‘‘ canaux veineux des os,” and his particularizing Fleury, in his preface, as the real discoverer.

I n 1819 lie gave to the world his masterly exposition of the veins of the vertebral column, and made a passing reference to the veins of the diplog in speaking of intra- osseous venous channels in general. He returned to the diploic veins again in 1826, when he described them in some detail in a paper in German (“ Nova Acta Physico-Medica, Naturae Curiosorium,” Bonn). He describes their development from half-canals at the centres of ossification of the principal bones (this, in passing, the present writers have confirmed). He also describes the minute pitting of the walls of these canals, proving that they are fed by innumerabIe venules from the meshes of the diploe.

Mention has already been made of Breschet’s papers.

THE VEINS OF THE DIPLOE

Brcschet’s real claim, in popular estimation. to association with the diploic vessels, rests without question on the publication in 1530 of a superb volume, Recherches Anatomiques, Physiologiques, et Pathologiques sur les Canaux Veineux des 0s . This beautifully illustrated work was an ambitious undertaking, and Breschet did not live to see i t completed. It is an ironical fact that although there are twelve chromolithographic studies of the veins (four of which we are able to reproduce, by courtesy of the Librarian of the Royal College of Surgeons), there is no description of them in the text, no doubt owing to the unfinished state of the monograph. But judging from the plates it is evident that Breschet’s studies were le ry complete, and had been carried further since his German publication. His account of the spinal veins has never been surpassed, and remains the standard description to this day. KO doubt the diploic veins would in time have been equally described ; in any case the beauty of the plates and tlicir sclf-explanatory clearncss has com- pensated for lack of text, and causcd his name to be associatcd by a later agc with this system of calvarial veins. In this posterity has unwittingly given him greater credit for originality than i w 5 his due, but knowledge advances step by step, and the final embellishment may be worth more than tlie bare outline of a first observation.

Forty years later Trollard, in a ThBse dr Palis (“ Recherches sur 1’Anatomie du SystGmc Veineux du Crane et de 1’Enckphale ”), enters into a new description of tlie veins. He dissociates himself from the classical descriptions of Chaussier and Breschet, bclieving that the diploe is a spongy tissue with areolz full of blood. The walls, according to him, are absorbed as age advanccs, and thus irregular channels are formed, but no definite or constant venous trunks. The earlier writers had believed that the vessels which they could easily trace with thc naked eye arose from small radicles. This belief Trollard also combats, setting up in its place the idea that tlie veins start in blunt lacunz, acquiring at once their full width. This point is worth mentioning, because on rough dissection thc veiris do indeed often appcar to conimencc in this wise. All veins save the largest trunks do notoriously vary greatly, and, so far as conccrns this point alone, Trollard may have had some justification for his %iiews. But modern injections and X rays prove that he was funda- mentally wrong.

Anothcr French monograph, one by E. Boismorrcau, deserves some- thing more, perhaps, than passing ,refcrencc. In 1904 he published his inaugural thesis, “ Contribution B 1’Etude de la Vascularisation du Diplo&,” and gives a very sober and well-documented description of the diploe and its vcsscls, confirming the views of the earlier writers as against those of Trollard.

Elsberg and Scliwartz have dcscribcd the radiographical appearances of thesc veins with special reference to meningeal endotheliomas, and ha) e given them a certain significance. Our own observations show that the veins may be well seen in perfectly healthy persons, whilst in a large series of tumour cases only occasionally was i t possible to establish any notable increase in the size or field of distribution of the veins.

We shall sce, however, that this conception is incorrect.

One last paper calls €or comment.

76 THE BRITISH JOURNAL OF SURGERY

THE NORMAL VASCULARIZATION OF THE BONES OF THE CRANIAL VAULT.

The worker eager for information on tlie normal means of vascularimtion of the cranial vault will find very little to help him in readily accessihlc literature. It is evident that the flat bones of tlie skull, having no epiph?scs, and a natural history of growth arid function whieh differs widcly from the long bones of the limbs, will ha, e a. blood-supply dilfering quite distinctly. In the long bones there is a system of nutrient arteries, one (or more) of which enters the shaft and divides to run to the opposite ends of the ~nctiiillary cavity, where i t anastomoses with the mctapliysial sets. These nutrient arteries, clcspitc the somewhat large openings in the cortex of tlie bone. are iisiinlly surprisingly small when studied by opaque injection and X rays. The calr-arium, on the other hand. prewnts a different picture. In the place o f the single nutrient foramen there arc a number of small openings, limited to \reIl-ctefiiieti areas. the sites of which differ materially on the inner arid outer surfaces. The outer table is generally smooth slid T ery faintly pitted. but no openings Iargc enough to adini t ix ricctllc point will be found except in the areas of niuscular attachnicnt, as in the anterior part or tlic teniporal f0v.a. and particwlarly iii the occipit:tl region below the superior c*urvcd liric, where a variably large riurnher will he found. These give entr:mce to branches of the rnuscwlar arteries which pierce tfie boric for its supply, finr 1 csscls with a short course, making up in riuinhcr Mliat they lack in siz-. The foramina equally gi\ e exit to diploic \ cins. It is a cwnimonplace cxpcrieiicac of cerebellar surgicd approach to rncet with free venous oozing below the frinqe of muscular attachment as the muscles arc swept off the occipital hone. The divided vessels a le apt to he loosely referred to by tlie operator as effcr- cnts of the lateral sinuses and torcula. More often they ale riot true emissaries. that is, freely perforating 1 esscls, but arc diploic eflcrents. This is clearly demonstrated by the beliaviour of the troublesome bleeding points often cncoiintered about the external occipital crest. for bleeding from them is easily stopped with wax. arid when the bone is rongeurcd away tlic dural surfacc bene:ttli is smooth and dry.

Apart from tliploic connectors of this kind there are no noteworthy openings on the cranial vault save those of tlic well-known symmetrical eniirsuries, the niastoid, parietal, and so forth. Careful study of these latter foramina will frequently show that as they pierce the bone they arc joined by chploics reins, a small perforation or two being disco\ erable in their smooth w,1'~1ls.

The arrangement of nutrient T cssels is quite different on the inner suriace of the qkull, which, apart froni tlic irregularities due to corivolutional marking. presents the charactcristic meningeal vessel grooi es. On this surface again u'c find the multiple foramina which we saw a t cwtain points on the external table, and once more they are strictly limited in their distribution ; but now they oec'ur only in thc meningeal grooves and in and about tlie grooves of the great dural venous sinuses, a fact which gnes us a clear lead as to the function of the meningeal vessels.

THE VEINS O F THE DIPLOE 77

The Meningeal Arteries.-The meningeal arteries, and particularly thc middle, are so hallowed by association with a clinical syndrome, that, the reason for their presence may often escape observation. We may well nsli ourselves why a fibrous nienihranc whirli should require no more vascularization for its own nceds than the fascia lata of the thigh should be so richly supplied with vessels. For the dura is indeed very freely supplied with vessels-vessels so small and so easily controllcd a t operation that one is apt to be misled as to their number. We must confess that, with preconceived view formed :it operation, injected specimens of dura came as a surprise ;

FIG. 5l.--Kadiograrns of calvariwn of dry skiill. Diploic vessels in blue, meningeals in red.

niaiiy fine brariches will be scen ramifying up to arid beyond the sagittal k u s . The injections confirm the ahscnce of any special meningeal arterial supply to tlic Pacchionian bodies. But from our point of view- at the rrioriient, the srn:tll puffs of lipiodol seen along the vessel arid a t the cnd4 of the twigs of tlic arterial tree are of more importance. These represcitt the points a t which the5e fine vessels were entering the bone as nutrients. \I'hrn the artery, on surh a specimen, is washed out with water, smdl pools collect at many points for the same reason. Conversely, when nater


i \ forced into any channel i n tlic sawn cdgc of a removed calxarium a t post-mortcni the inner table is seen to ‘weep ’ in like manner. It is quite evidcnt, then, that tlie nicniugcal vessels are not destined for the supply of that ineinbranc alone. but rather for the overlying bone, of wliicli tlie outer laycr of the dura has long heen known as the inner periosteuni. At the point whcrc tlic middle nieiiingcal vessels tunnel the greater wing of the splienoitl, opportunity is taken for tlic iiitcrcliarigc of vessels with the interior of tlic hone, T ciioiis conncctioiis bcing made here in pttrticular.

FIG. 52.-Lipiodol injection of the iiiciiingcnl wsscls in tho hone.

though aiirZ\toniosc$ ocwir besidcs at all points along the course of the \ essel5.

Meningeal Grooves.-It will be admitted bl- most who liavc worked a t tlie subject that Wood Jones was correct when he re-established thc old teaching and assigncd to the veins the chief part in thc formation of the meningeal grooves. So often a t post-mortem one finds a deeply-cut groove running up to tlie parasagittal sinus and Paccliionian markings, whilst tlic artery supposcd to have caused the bony track is seen tapcriiig away until it is so thin above as to liavc been quite inadequate to occupy the wide furrow. It is a fact that the middle meningeal vcssels, and their grooves, make their way up to the Pacchivnian bodies, essentially veiioiis structures. There is a capillary system a t the origin of these veins. for on section in tlie living there

THE VEINS OF THE DIP LO^ 79

is not that scvcre reflux bleeding that would occur if they connected directly with the sinus.

The Vaseularization of the Calvarium.-h summary i t may be said that the bones of the vault are supplied with blood by branches of the meningeal vessels, and particularly the middle meningeal ; that these branches penetrate the inner table and are generally of small size. Reinforcement is effected by arteries which enter the outer table, particularly in the areas of muscular attachment. But thc larger channels in tlic bone are, as we shall see, essentially venous, an anatomical corroboration of another operative observation-that bleeding from the cut or nibbled calvarium is predominatingly vciious in type. The vascularization ol the cranial bones may be rcgarded as a seepage from very numerous vcssels. It seems probable that this is not it unique method of circulation in bone, for the supply of tlie ends of the long bones and the compact tissue is of a rather similar typc. In the cranium it would appear that the meningeal arteries replace the long nutrient artcrics of tlie limbs, the extra- os,eous course of the former being an exigencc of diffcrerit bony function and structure. Now it is a wcll-accepted fact that an osteoplastic flap may bc lifted witliout fear of necrosis of the bone, so long as i t remains attached to the temporal niiis- clcs : adhesion to the overlying skin is riot essential. Thcrc is no

FIG. 63.-The occipital veins of the diploe. !From (lucStioK' that at times rcplaced a specimen in the Rfuaeum of the lioyal Collcgc of Sur-

bOKie-fhps must approach the geons, Edinburgh. Note the dept.h from thc surface.)

category of free grafts ; and it is equally a fact that porosis of flaps does at timcs occur, though rarely. These honc segments are free of the dura when the bone is reflected and tlie fine vessels entering from this side are torn off. This deprivation is, as has been said, not a serious matter, so that whilst one may truly lay i t down that the meningcal vessels are largely for the usc of bone rather than of the fibrous matrix in which they lie, they are not in themselves essential for the continucd life of that bone. Not only will the bone survive, but i t is a t times re-united by bridges of new bonc. Union may be expected more often in the young, though we have seen i t in older people; therc seems to be no rule on this point. A flap a year old in a man of 30 was recently re-turned and fibrous union only was found; in another, reopened after nine months (male, age 42), there was firm bony union along one border but not elsewhcre; in yet A third (male, age 30) the flap six years later was found to have re-united in almost all of its circumference, though a groove marked the position of the original section.


THE ARRANGEMENT OF THE DIPLOIC VEINS.

FIG. 54.--Diploic veins from a normal inan of 55.

Hresvhct's own figurcs can scarc*cly be bettered, 50 i t c haxc c+liosci~ to illustrate this note with four of them (Pigs. 47-50). They arc so clear that little explanation is needed. As with \ enous channcls elsewhere, considerable variation in size and position is to he cspccted. They he ricarer thc inncr than thc outer table, and whilst each of the bones of the bault seem5 to ha re a set particnlarly of its own, connecting branches cross the sutures to unite the rarious groups. Thc veins, as seen in skiagrams of the living, group themselves into threc main sets, frontal. parietal, arid occipital. A V-shaped arrangement with the apcx downwards is very characteristic (see Figs. -17, 4X, 50). cspecially in the frontal region. The exit of these frontal veins by a small foramen in or about the supra-orbital notch is clearly seen in most dried skulls. Thc occipital set drain into largr channcls, one on either side of the mid-line, converging toward5 tlic base. The much larger parietal set includes the anterior arid posterior temporals described by Brcschet arid others. Of the two, the posterior group are those most commoiilp seen in X-ray photographs of the living, and connections with the occipital diploic vcssels arc common, whilst the :rritcriov temporal diploic, arc hard to see, for confusion arises between tliem and the grooves of the meningeal .r-e\sels,

THE VEINS OF THE DIP LO^^ 81

with which they are closely comiectccl. Fig. 50, the skull of an old man, shows actual clefccts along thc course of this vein. Examination of tlic meningcal grooves in the iritier table of the aged reveals, not the fine pitting of younger skulls, hut many places where the floor of the groove is missing to a greater or lesser extent.

It is important to rccognizc that this ariastornosis takes place between the diploic channels and both the anterior and posterior divisions of the micldlc meuingeal, for on the skiagranis of living sltulls i t is not uncommon to see tlie nieriingcal grooves run back and up, t o be lost towards their termination in a typically diploic constellation.

We have confirmed the course and distribution of the diploic veins by thc st,udy of X-ray photographs both of the living and of dry skulls. Three attempts at injection on tlic cadaver with Fcrguson's mass did not give the results expectcd. In the dry skulls the specimens used were either calvaria which Iiacl becii separated from the remainder of the skull by a horizontal cut, or lateral halves of skulls which had been divided in the sagittal plane. I3y using these i t was possible to avoid the images of tlie veins of tlie two sides being superimposeci on the film. It Iiad, liowevcr, t ~ i e disadvantage, in the specimens o f tlie calvaria, that only the superior portions of the veins could he seen.

IVhen the X-ray films of thc dry skulls (Fig. 51) were examined and compared with tlie dural aspects of the skulls themselves, i t was found that not only were tlie grooves for the meningeal 1-esscls shown on the film, but also other impressions obviously made by other blood-vessels. These were the diploic veins. It is not a difficult mattcr to distinguish the diploic from the meningcal channels without cxaniiiiing tlie inner aspect of the skull, as the former have certain cl1aracteristic.s : (1) While the general course of thc nrcningcal vessels is upwards and backwards from tlie region of the small wing of the sphenoid, the diploic veins often run at right angles to this direction (especially in the posterior parietal region). (2) The origin of tlic larger diploic veins tends to be bluut. (3) There is a curious star-like branching and ariastomosing of veins, which we term the ' spider ' (Figs. 56-59). This is usually best seen in the parietal region, but may occur clsewlicrc. (4) The Y-likc hraricliing of the wins, commonly with short thick limbs, may be clearly mrtde out.

\Then skiagranis are taken of the living skull, the results are com- plic~ited by tlie superimposition of tlie groovcs of one sidc upon those of the opposite side, when seen in a film. Tlie diploic markings, however, have the saiiie c:haractcristics as seeti in tlie dry skull, which renders i t comparatively easy with practicbe to clistinguisli tlie tliploicb vcins from tlic meningeal vessels. The edgcs of the diploic grooves arc quite sharply dcfined, but frequently show a rccognizablc crenation.

In the film of tlic dry skiill, altliough it was quite simple to trace out the course of tlie main diploic vessels, it, was tlifGcult to differentiatc tlic finer groovcs by simple comparison of tlic skull arid the film. To overcome this dilliculty the following tec~liniquc was adopted. On a matt print of a film a11 tlie larger nicningcal grooves, as observed on the inner surface of the skull, wcre painted in red, and then by comparing the skull and t,lie film all the larger

VOL. XVI.-NO. 61. G

Here tlie two systems become confluent.

THE BRITISH JOURNAL OF SURGERY

FIG. Rli.-Drawing from X -rag pliotogritplis of variations in the diljloic vein? (continuous In thr: tl i i i . i l tllere is a frtlcturr ; tho horizontal 1inesJ and riionirigeal vessels ( d o t t e d Iirics].

liiiil> \vas reported as ending in a " stellatr crack."

THE VEINS OF THB DIPLOE

DIPLOIC VEIXS SIIOTVIXG THE ' PARIET-iL SPIDER '.

FIG. %;.-Al male, age 24.

83

FIG 57.-A male, ago 28 .


DIPLOIC Vlsrxs SHOWING THE PARIETAL SPIDER ' -co~zti i izied.

FIG. 58.--8 inale, age 48.

FIG. 59.--A fernale, age 60.


diploir grooves were painted in blue. Then by a careful examination of the film, which showed more details than the print, it was possible to differentiate arid paint in many of the smaller vessels. Fig. 51 shows a print dcalt with in this way, and gives a very clear idea of the distribution of the diploir veins. The rcsults obtained by the methods described above generally confirm the findings of the older observers. The frontal, posterior, temporal, and occipital veirir were easily traced, and i t was found that the posterior parietal and thc occipital constantly and freely anastomosed with each other in tlie parietal region, forming the ‘ spider.’ The frontal diploic veins were more isolated, arid connections c.ould only rarely be traced between them and

FIG. 60.-Diploic wins in a case of adult hydrocephalus of long standing showing the lakes of confluence.

the other veins. It will be noticed that no mention has been made of the anterior temporal vein. This is due to the l a d that i t wa5 not seen in the dry skulls and cannot often be unequivocally distinguished in tlie livinc. Its place frcquently appears to be taken by a vessel grooving the inner aspect of the skull in front of thc middle mcnirigeal grooves. which frequently originates in a depression near to tlie great longitudinal sinus ; i t ends in the sphenoparietal sinus. We are of the opinion that this vein may be thc anterior temporal diploic vein placed more deeply in the dura than thc other diploic vessels, which are placed more superficially in the bone.


Its fate sccms thcrcfore to be I)oimd up with that of tlic anterior division of the iniddle meningeal vesscls. Fig. 60 is from an old-standing hydrocephalus (female, age 2-2). The sharp-cut groove for tlie middle meningeal vessels is replaced by a chain of srriall pools of bloocl. This figure may bc most uscfully compared with Breschet’s figure (Pig. 49). (This possible interchange has been noticcd hy Coen, and is referred to in a paper by lhonipson, which we have seen only after the aboic was written). The \cry dcep iriarkings of tlie meningeal p o o l es figured by Elsherg and Schwartz may hare a similar genesis.

CLINICAL APPLICATIONS.

r ,

In surgical pr:wtice the veins of the diploc will niost ofteu cause confusion in X-ray cases of head injury ( F i g . 61). It was, indccd, the report of a radio- grapher that eutensi~~e stellatc fractures wcrc prcsciit in the parietid region of’ two patients who had had no injury a t all, that drew the attciition of oiie of us to tlic problem of the calwrial vcssels. Generally a. fracture line is easy to

FIG. I t 1 --X lax 5hiining tiiploic ~ e i i i 5 on tlic iight, , r i i ( i a fidclure cutting the lcft oibit,tl rirarpn and iiinulatiiig A tliploi(* \?in. ‘Chc line <if fractiiro IS slio\\n hy the :irrn\vi.

distinguisli owing to its straightness, its clear-cut niargins, and its cstent. The great safeguard is an atlequate knowledge of the normal nppc:trances of tlie veins, tlicir position arid dircction. their tendency to enastornose and form ‘ spiders,’ stars, and Y-junctions. We ha\-c foiiiid c*liiiically that the most difficult tracks to assess are ttio5e parallel with the contour of the skull high in the parietal region. It niiist he reinemhered that the veins, like


fr:ict.ures, often run across siitnre lines, biit anyone familiar with thein will liardly fail to distinguish theni from injuries. A mistake in a case involving a ci\-il action a t law, as in the now conimon motor accident, may be costly. Further, i t is possible that, deep venous crosioiis may assist in dcteriiiining tlic line of fracture, as Elliot Smith showed years ago and as Tlionipson aga,in suggests.

A dilatation of the vcins in the diplot: might be thought to be a likely concomitant of intracranid tumour, with its 11rcssure on the venous sidc. IVc have refcrred to tlie serious venous oozing met with at ccrtain times and in certain places. and emphasized that tlie bleeding is commonly from diploic efferciits as well BS from perforating emissaries. Now it is quite true that tlic eye skilled in the detection of tlic diploic channels in skiagrams of the living may frequently note lierr an unusual clarity in t.lie vessels' lines, tlicre an iinconinion pool of blood. Yet tlie fact reniains that the most beautiful csaniplcs of diploic veins that wc have seen hare liecn discovered by c h i i c e in skiagrains of non-tunioin- cases. The observer would tlicrefore be very wroiig if he concluded that because the veins were very distinct a tuniour was present iri t.hc skull. I n children witli their sparse diploc the wins are small and hard to define ; as age advances they become clearer. When the skull is thinncd by espansion in hydro- cqihallus above infancy the vcins arc again ill-seen? save that, around tlie grcat nieningeal collect,ing t,runks cliploic markings become more evident (Fig. 60) . Ihit i t is impossible t o lay down H rule that shall be true of every case : some will demonstrate one point and not anotlier. There seems to bc some ground for tlie views of older writcrs, tha t the diploic systcni acts as an additional resen-oir for the blood circulating within the craniuni and might act as an escape or ba1anc:ing mechanism when that, current is disturbcd. Operative experiences with turnour cases support tliis belief.

111 nieningionia involving t,lte overlying bone t,liere is no yucstioii as to thc increa.set1 diploic bleeding, clca.rly localized as to its source by tlie uniforiii failure ol' ligature of tlie external carotid artery to abate it. It is evident tliat tlie time factor must he very important, and that if diploic irrigation is to he increased in a tunioiir-bcarer a considerable period must clapse before di1nt:ition recognizahlc on an X-ray film can occur. We can only repeat that iiifcrenccs drawn from the radiological appearances of t.liesc veins without refer- ciicc to otlier more iniportant clinical factors will alniost certainly bc faulty.

Acute pyogenic osteoniyelitis is rarc i n tlie vault owing to the absence of epipliysial lines. On tlie otlier hand, tlic i-eiioiis c*lianncls allow of easy spread from one arca to another, and tliis explains the patchy distribution of calvarial infection when it does oc(wr. d cast reccntly observed will serve as illustration. A young man began with 21 furuncle on the nose which rapidly caused rrdema and ccllulitis in the orbit. After a stormy coiivalesccnce a deep tenipord abscess formed. Later patches of ostcomyelitis developed in tlie frontal and high in tEic parictal region. Infectioii could easily find its way by IiieaIis of i t septic, thoiiiboplilcbitis originating in the deep vcins of the temporal fossa and spreading by way of the vessels, which enter and leave the bone in this region, with septic permeation and osteoniyelitis a t a distance.

The age factor has been reniarked on.

Onc last word, and that on infection.


SUMMARY. The discoveries of our forefathers ha\ e a habit of attaining a new iniport-

ance inany decades later. This is exemplified by the veins of the cranial diploc, which rcfiiieiiients of X-ray tecliiiique now render clearly visible in most radiograms of the living sk~dl . These veins, which owupy very definite cliaiiiiels in the substaiicc of the bone, may be easily mistaken by tlie unwary for fractures. Generalized eiilargemcnt, detectable by radiography, is not the rule in cerebral tumour, and beautiful examples may be met with in normal persons, especially in the later decades of life. Unusual clarity and breadth of the middle meningeal grooves is more often met with in cases of intra- cranial tuniour. In these cases tlic anterior temporal diploic veins add their quota to the inipress of the nieningcal vessels. The meningeal vessels, both arteries and veins, are destined to a considerable extent to supply the bone.

Figs. 47 to 50 are photogmphs froin Brcschet’s book made by kind per- mission of Mr. V. G. Plarr, Librarian to the Royal College of Surgeons. Figs. 51. 55 , and 60 are by Miss Davisoii. We are indebted to Mr. Greig for Pig. 53. We have to acknowledge also tlie interest which Mr. Higgiiis, Radiologist to thc Salford Hoyul Hospital, has taken in the work, arid are indebted to Dr. Morris, of tlie same department, for the prints of Figs. 56-59. Profe5sor Stopford has been most kind (as ever) in allowing the free use of material in the Department of Anatomy.

BIBLIOGRAPHY. DUPCYTREN, G., Propositiorrs s w guelques Poiills d’.,l riatoit&, de Physiologic, et d’Airalornie

CIIAUYSIER, Rxpositio)i Som?ririire tle l a StTucture el tics U<ffPrer~ts Parties dc 1’EncPphale

BRESCHET, G., Rssni sur lcs 1.ciitt-s du Rnchis, Paris, 1819. BRESCIIW, G., .‘ Anatomisch-Physiologische Untersuchungen ubcr einige neuendeckte

Theile des Veiien-systems ”, Xora Acta Pliysico-Metlicu, Acad-Cacs. Leopold-Carol, Naturae Curiosorum, Bonn. Tom. dec.. 1826.

BRESCHET, G., Kecherches Anatoitiiques. Physiologicities. et Pathologiqucs sur le S y s t h e aeiitetcx, rt spx%~le~r~eni swr lcs C a m m Veiirrzta ries Os, Paris, 1830.

RACIBORSKI, A., IIisfoiTe des Dicoirvertes relcitilres nu SyslPwre Veirteux, Paris, 1841. TROLLARD, P., ’‘ Recherche sur l’Anatomie du Systhiie veineux dc l’Enc6phale et du

Crane”, ThPse dr Paris, 1868, No. 250. BOISMORREAU, E., “ Contribution li l’$tude cle la Vascularisation du Diplog ”, These

de Borrlrtiua. 1903.. SXI~’H, G. ELLIOT, ‘* A not.e on Nervous Lesions Produced blechanically by At.hcro-

iuatous Arteries ”, Iterr. Scurol . nrctl Psychicit., 1905, iii, 182. JONES, Woou I?., ‘‘ On the Grooves upon the Ossa l’arietalia conimonly said to 11c

caused by the Arterin Bleniugea Media. ”, Joicr. Atcut. mid Physiol., 1912, xlvi, 228. ELSBERG, C., and SCIIWARTZ, C . W., ‘- Increased Cranial Vascularity in its Relation to

Iiitracranial Disease, with special reference to Enlargement of the Veins of the l)iplG and its Relation to the Endotheliomns ”, Arch. of Scuro l . riird Psychicit., 1921, xi, 292.

COEN, B., ‘. A Communication as to thc Causation of Large Vascular Grooves found on the Inner Aspect of the 0 s l’arietalc ”, JOUT. Ll?inf. coid Physiol., 1914, slviii, 293.

On Certain Grooves upon the Deep Aspect of the Cranial Vault ”, Cariud. M e / / . A.s.soc. Jour., 1920. Ort., 1194 : ‘‘ A Note concerning the Radiographic 1)ifferent.iation betwecn Diphie and ,&Ieriingeal Vascular Char~nels, Ibid. , 1927, Jan., GI.

palhologique, Paris, 1803.

O I L Cerueau, Paris, 1807.

TiioMPsox. I. MAC‘LAREK.

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On the veins of the diploë