Countercoup Skull Fractures

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Contrecoup skull fractures

CHARLES So H1RSCH, M.D., AND BENJAMIN KAUFMAN, M.D.

Departments o f Pathology and Radiology, Ca se Western Reserve University, and theCuyahoga County Coroner's Office, Cleveland, Ohio

o,' The au thors describe the frequ ency, patholog ical features, and significance of con-trecoup fractures o f the anterior cranial fos sae, which occur comm only wh en fallswith occipital or temporal impacts cause fatal head injuries.

K E y W O R DS 9 h e a d i n j u r ie s 9 c e r e b r o s p i n a l f lu i d r h i n o r r h e a 9

s k u l l f r a c t u r e s 9 c o n t r e c o u p f r a c t u r e s

C ONTRECOUP bra in co ntu sio ns oc cu roppos i t e a po in t o f c ran ia l impac t ,i ndependent ly o f sku ll f rac tu res , and

a re sus t a ined when the mov ing or fa ll ing heads t r ikes a so l id ob jec t . Rout ine exper i ence inthe medico lega l au topsy room rea f f i rms thev a l i d i t y o f th i s w e l l - k n o w n p r i n c i p l e ;however , occur rence o f con t recou p sku l l f rac -tu res , a phenomenon a l l eged ly known to H ip-pocra tes , 1 has received scant c l inica l reco gni-t ion . In th i s pape r we draw a t t en t ion to thef requency and pa tho log ica l f ea tu res o f suchfractures, and discuss their significance.

G e n e r a l F e a t u r e s

Cont recoup sku l l f rac tu res a re loca ted a t ad i s t ance f rom a po in t o f c ran ia l impac t an da r e n o t d i r e c t e x t e n s i o n s o f f r a c t u r e sor ig ina t ing a t t he po in t o f impac t . Th ey occurwhen the v i c t im ' s head s t r ikes a t t he occ ipu t

or t emple , and a re loca ted most f requen t ly inthe o rb i t a l roofs and e thmoid p la t e s . F rac -t u r e s m a y o r m a y n o t b e p r e se n t a t th e p o i n to f impac t .

The orb i t a l roofs , e thmoid a reas , andan te romedia l r ecesses o f the midd le c ran ia lfossae commonly show foc i i n which bone i sso thin tha t i t i s t ranslucent (F ig. 1) . Frac-

tu res in such "egg she l l " a reas a re p roducedby t r iv i a l fo rce compared to tha t r equ i red tof rac tu re th i cke r pa r t s o f t he sku ll . A t au top sy ,w e h a v e d e m o n s t r a t e d t h e d e l i ca c y o f th e seregions in some individuals by intent ional lyc rack ing th in po r t ions o f the o rb i t a l roofsw i t h s i m p l e f i n g e r t i p p r e s su r e f o l l o w i n gr e m o v a l o f th e d u r a m a t e r .

Th i s d i scuss ion i s no t conce rned pr imar i lywi th penet ra t ing injur ies of the skul l, butgunshot wounds i l l us t ra t e some of the sa l i en tfea tures tha t we wish to e lucidate . Fur ther-more , f rac tu res in the an te r io r fossae inducedb y t h e t r a n sm i t t ed f o rc e s o f g u n sh o t w o u n d sproduce pa lpebra l ecchymoses iden t i ca l w i ththose in the con t reco up f rac tu res o f b lun tt r a u m a . C o n t a c t - r a n g e g u n s h o t w o u n d s(muzz le o f the gun pressed aga ins t t he sca lp ) ,rega rd less o f t he pa th o f the bu l le t , com m onlycause f rac tu res in the an te r io r c ran ia l fossae

tha t a re no t ex tens ions o f f rac tu res rad ia t ingf rom the m arg ins o f bu l le t pe r fora t ions in theskul l . In this s i tua t ion, orbi ta l and e thmoidf rac tu res a re no t t rue con t recoup in ju r i e s .T h e y a r e p r o d u c e d b y t h e p r e s su r e o f e x -panding gas b lown in to the sku l l beh ind thebul l e t, t r ansmiss ion of fo rce th rough thesku ll , and s l amm ing of the b ra in aga ins t t he

530 J. Neurosurg. / Volume 42 / M ay, 1975



Contrecoup skull fractures

f loor o f the sku l l in r e sponse to the shockw a v e imp a r t e d t o t h e c e r e b r a l p a r e n c h y m a b yt h e b u l l e t ' s k i n e t i c e n e r g y . T h e l a t t e rme c h a n i sm a l so e x p l a in s t h e c o mmo n o c -c u r r e n c e o f b ra in c o n tu s io n s d i s t a n t f r o m th e

bulle t t rack.F igure 2 shows the v ic t im of a sma l lc a li b er , c o n t a c t - r a n g e g u n sh o t w o u n d in t h er igh t f ron ta l a rea . The bu l le t pe r fora ted thef ron ta l lobes o f the b ra in and d id no t s t r ikethe orb i ta l roof s . Consp icuous pa lpebra le c c h y mo se s w e r e c a u se d b y c o m m in u te d f r a c-tu res o f the an te r io r fossae wi th r e su l t inghemor rhage in to the o rb i ta l so f t t i s sues . Theecchym oses a re r e s t r ic ted by fa sc ia l p lanes o fthe eye l ids ( so-ca l led " spec tac le" hemor -

rhages) , and th e re is no s ign of b lun t t r au m ato the f ron t o f the f ace . N ote the s imi la r d is -t r ibu t ion of pa lpebra l ecch ym oses in F ig . 3upper le f t . Co mp a r a b l e f r a c tu r e s a l so a r ep r o d u c e d b y d i s t a n t w o u n d s f r o m p o w e r f u lh a n d g u n a mmu n i t i o n a n d f r o m h ig h v e lo c i t yr i f le bu l le t s ; con tac t wounding by e i the r o fthese f r equent ly causes exp los ive hemide -cap i ta t ion .

Mater ia l s an d Meth odT o d e t e r min e t h e a p p r o x ima te f r e q u e n c y o f

cont recoup sku l l f r ac tures , we rev iewed aconsecu t ive au topsy se r ie s o f adu l t f a ta l i t i e sf rom head in jur ie s sus ta ined in acc iden ta lf al ls in 1972 and 1973 in Cu yah og a Co unty ,O h io ( me t r o p o l i t a n C le ve l an d ) . E a c h o f t h esu b je c ts h a d a c o m p le t e a u to p sy p e r f o r m e d a tthe C oron er ' s Of f ice. We e lec ted to s tudy v ic -t ims of acc iden ta l f a l l s because these in -d iv idua ls commonly sus ta in a s ing le c ran ia limpac t ; in th i s c i r cumstance , cor re la t ion oft r au m at ic le sions in the sca lp , sku ll , and b ra inlends i t se l f to r e l iab le r econs t ruc t ion of thel e t h a l m i s h a p . I n c o n t r a s t , v i c t i m s o fhomic ida l a ssau l t s and veh icu la r c ra shesof ten have ex tens ive and mu l t i foca l sca lp andfacia l in jur ies , m or e dif f icut~ to interp re t inthe con tex t o f the p resen t d i scuss ion .

Dur ing th e 2 -yea r s tudy pe r iod , 119 adul t sd ied f rom head in jur ie s sus ta ined in acc iden-

ta l fa l ls , with autopsies performed a t theCu yah oga C oun ty C oron er ' s Of f ice; 38 (32%)of these ind iv idua ls had no sku l l f r ac ture o fany type . Of the 81 pe r sons wi th sku l l f r ac -tu res , s ix were exc luded f rom the s tudybecause they e i the r had mul t ip le c ran ia l im-pac ts, a s f rom tum bl ing down s ta i rs , o r the i rskul ls were vir tua l ly shat tered, as in a fa l l

FIG. 1. Ph otograph of d ry sku ll w ith calvariaremoved, viewed upward into the orbits and nasalcavity, illustrates translucen ce of orbital roofs andethmoids. B on e defects in t hi s specimen are ar-

tifacts.

FIG. 2. Pho tograph of victim of contact-range,small caliber gunshot w oun d of the r ight frontalarea. Palpebral ecchym oses, cau sed by shatteringof the o rbital roofs, a re restricted by fascial planesof the eyelids. Photograph by cou rtesy of the O fficeof the Chief Medical Examiner, Baltimore,Maryland.

f rom a grea t he igh t . In those s i tua t ions themul t ip l ic i ty and seve r i ty o f c ran ia l in ju r ie sprec luded assignment of f rac tures to specif ic

po in ts o f impac t .O f the r em a in ing 75 ind iv idua ls wi th f r ac -

tu res , n ine (12%) had con t reco up f rac tures inthe an te r io r o r m iddle fossae , two of wh omdid no t hav e a f r ac ture a t the po in t o f impac t .Direc t ex tens ions o f f r ac tures o r ig ina t ing a tt h e p o in t o f imp a c t i n to t h e a n t e r io r o r mid -d le fossae was no ted f r equent ly , bu t these

J. Neurosurg. / Volum e 42 / M ay, 1975 531







C. S. Hirsch and B. Kaufman

t y p e s i n t h e s a m e a n a t o m i c l o c a t i o n s .Bacter ia l m eningi t is i s the cardinal la te seq uelof e thm oid f rac tu res o r o f o rb i t a l f rac tu restha t communica te w i th l a t e ra l ex tens ions o fpara nasa l a i r ce ll s. Prog ressive thinning o f

the un torn dura ma te r ove r an unhea led sku l lf rac tu re m ay l ead to fenes t ra t ion and pe r fora -t ion many months o r yea rs fo l lowing theor iginal in jury, resul t ing in la te onset ofcerebrospinal f luid f i s tulas .

The most l i ke ly mechani sms caus ing con-t recoup f rac tu res in c losed head in ju r i e s a ret ransmiss ion of fo rces v i a the sku ll and d i rec t

t ransmiss ion of fo rce f rom the po in t o f im-pac t t h rough the b ra in to the f loor o f t heskull . 2

References

1. Co urville CB: Forens ic Neu ropatholog y.Mundelein, Ill, Callaghan, 19642. Gurdjian ES, W ebster JE: H ead injuries.

Mechanisms, Diagnosis, and Management.Boston, Little, Brown, 1958

Address reprint requests to: Charles S. Hirsch,M.D., Cuyahog a C ounty Coroner's Office, 2121Adelbert Road, Cleveland, Ohio 44106.

534 J. Neurosurg. / Volum e 42 / M ay, 1975

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Countercoup Skull Fractures