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Am J Roen tge no / 128:235 -238 , Februa ry 19 77 23 5

Anatom ic , C lin ica l, S u rg ica l, and R ad iog raph ic Co rre la tion o f th eZygom a tic C om p lex F rac tu re

AM IL JAM ES GER LOCK AND DOUG LA S P . S IN N2

Unde rs tand ing th e m echan ism s by w h ich c lin ica l s ignsand sym p tom s a re p roduced is a pre requ is ite to th e co r-re c t ap pre c ia tio n o f ra d iog rap h ic fe a tu re s . R ad io g raph s o ffac ia l tra um a a re no d if fe ren t in th is re spect. Th is pape rdescr ibes th e spec ific c lin ica l fin d ings assoc ia ted w itheach d isp la ced bony fragm en t o f th e zygom at ic com p le xfra c tu re . L im ita t ion o f jaw m ovem en t and fla t ten in g o f th echeek a re p roduced by depressed fra c tu res o f th e tern -po ra l p ro cess o r zygom atic arch ; un ila te ra l ep is ta x is is are su lt o f fra c tu re s o f th e zygom atic p ro cess o f th e m ax illao r th e flo or o f th e o rb it; p a re s th es ia o r anesth es ia o f th echeek re su lts from frac tu res o f th e in frao rb ita l p ro cess o ro rb ita l flo o r; unequa l pup il h e igh ts is assoc ia ted w ith fra c -tu re o f th e fron ta l p ro cess; and decre ased ex traocu la rm usc le func tion w ith d ip lop ia is c aused by fra c tu res o f th eo rb ita l p ro cess , fron ta l p ro cess . o r o rb ita l flo or . Thec lin ica l and rad iograph ic fin d ings a re co rre la ted w ithsu rg ica l m an ag em en t.

Introduct ionTraum a to th e zygom atic o r m a la r bo ne o f the fa ce canp roduce m u ltip le fra c tu res and c lin ic a l find ings . C har-ac te ris tica lly , the body o f the zygom a tic bone itse lf isra re ly fra c tu re d ; in s tea d , its w ea ke r p ro ce sse s and th e irsu rrou nd in g a ttac hm en ts a re frac tu re d and d isp la ce d [1 1 .K n ig h t a n d N o rth [2 ] re cogn ized th is in ju ry a s a c lin ica le n tity a nd re fe rre d to it a s th e m a la r fra c tu re . O th e r n am esa re z ygom a ticom ax illa ry fra c tu re , zyg om atic com p lexfra c tu re , an d trip o d fra c tu re .

T he m os t fre quen t c lin ica l f in d ing s inc lu de (1 ) lim ita tiono fjaw m ovem en t a nd fla tte n ing o f th e chee k , (2 ) u n ila te ra le p is ta x is , (3 ) pa re s the s ia o r ane s the s ia in th e d is tr ibu tio no f the in frao rb ita l ne rve , (4 ) unequa l pup il he igh ts , and(5 ) a decrease in ex traocu la r m usc le func tion w ith d ip lop ia .B y unders tand ing the m echan ism s o f the fra c tu res o f thep rocesses o f the zygom atic b one wh ic h cau se the se c lin ic a lf in d ing s and b y co rre la ting the se c lin ica l find in g s w ith thefac ia l rad io g raphs , a m o re a ccu ra te d ia g no s is andtrea tm en t p la n can be fo rm u la ted .

Ana t omyC omm on ly the zygom a is re fe rred to as hav ing a cen tra l

bony m ass o r body from w h ich th ree bony p rocesses p ro -jec t (f ig . 1 ). These p rocesses a re a tta ched by su tu ra l junc -tions to the fron ta l, m ax illa ry , and tem po ra l bones andco rres pond in g ly nam ed [3 ]. T he ir ro le s in fo rm in g thebony fac ia l ske le ta l fram ew o rk and the tem po ra l fo ssa ,orb it, m ax illa ry s in us and con tou r o f th e chee k w ill b edescr ibed and re la ted to spec ific c lin ic a l find ings .

C lin ica l and Rad iog raph ic F ind ingsL im ita t ion o fJaw M ovem en t a nd F la tten ing o f C h ee k

The tem po ra l p ro ce ss o f th e zygom a (fig . 1 ), a fla t w ing -like b lad e o f bon e e xte nd ing po ste rio rly from th e b od y o fthe zy gom a , fo rm s the an te rio r p a rt o f the a rch w h ichco ve rs th e low er po rtio n o f th e tem pora l foss a . T hepo s te rio r p a r t o f th is a rch is fo rm ed from th e zygom aticp ro ce ss , a lo n g th in p ro je c tio n o f b one p ro je c tin g an te rio rlyf rom the tem po ra l b o ne . T he se tw o pro ce sse s fuse to ge the ra t the zygom a tico tem po ra l su tu re . T he co rono id p roce sso f th e m and ib le w ith its a ttac hed tem po ra lis m usc le te ndonlies w ith in th e tem po ra l fo ssa and m us t p as s fre e ly b a ckand fo rth under the zygom atic a rch w hen the m ou th iso pened and c lo se d .

W hen th e bod y o f th e zygom a is dep re ssed inw a rd . th etem po ra l p ro ce ss can im p in ge on th e co ro no id p ro ces s o rtem po ra lis m usc le te ndon , an d th e pa tie n t w ill ha ve d if-f ic u lty o p en in g and c lo s ing h is m ou th (fig s . 2A and 3). T h iso ccu rs in abou t o ne -th ird o f p a tie n ts w ith a zygom aticcom p le x frac tu re [4 ]. F la tten in g o f th e la te ra l c on tou r o fthe cheek m ay a lso be pre sen t. s ince it is in pa rt fo rm edfrom th e unde rly in g bony suppo rt o f th e tem po ra l p ro ces s .A cu te ly th is m ay be obs cu red b y th e edem a and e cch ym os isw h ich ac com pan ie s th is in ju ry , an d it is no t un til th issw e lling sub s id e s tha t th e fla tten ed chee k o r s k in d im p lebe com es recogn ize d . W hen th e se fe a tu re s a re p res en t,the subm en ta l ve r tica l ra d iog ra ph ic p ro jec tion o f the zygo -m a tic a rche s shou ld be e xam in ed fo r de p re ssed fra c tu reso f th e tem po ra l p roc es s (fig . 3 ).

Iso la ted depre ssed zygom a tic a rch fra c tu res and fra c -tu res o f th e m and ibu la r co nd y le , co ro no id p roc ess , an dram us o f th e m and ib le w ill a lso lim it jaw m ovem en t.

Un ila te ra l E p is tax isThe m ax illa ry p roc ess is th e m ed ia l tr ia ng u la r su rfa ce

o f th e body o f the zygom a. It is a ttach ed to th e zygom aticp ro ce ss o f th e m ax illa a t the zygom a ticom ax illa ry s u tu reand lie s to th e s id e o f th e m ax illa ry s in us be low th e o rb ita lsu rface o f th e m ax illa . T h e m ax illa ry p roce ss is ra re ly fra c -tu re d ; in s te ad , the fo rc e from a b low to th e chee k is tran s -m itte d th ro ugh th is s o lid p ie ce o f bo ne to the w ea ke rad jo in in g zygom atic p ro ce ss o f th e m ax illa . T h is re su lts ina frac tu re o f th e z ygom a tic p ro ce ss o f the m ax illa a n dla te ra l w a ll o f th e m ax illa ry s inu s , tea rin g the m ucousm em b rane lin ing o f th e m ax illa ry s inu s (fig s . 2B , 2D , and4). S in ce th e nasa l ca v ity is d iv id ed in to tw o separa techam be rs b y the nasa l s ep tum , the re su lting b le ed in g fromth e no se is lim ite d to th e s id e o f in ju ry .

D epartm en t o f R ad io log y. Un ive rs ity o f Texas H ea lth S cience C en te r. D a llas , Te xas 75235 .2 D iv is ion o f O ra l Su rge ry . D epartm en t o f S u rge ry . Un ive rs ity o f Texas Hea lth S cience Cen te r, D a llas , Texas 75 235 . A ddress rep rin t requests to D .

P . S in n.

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23 6 GER LOCK AND S INN

F ig . 1 .-A na tom y o f the zygom a.1-5 , Tem pora l, fro n ta l, m axil la ry ,o rb ita l, and in frao rb ita l p rocesses o fz yg om a; 6 . f ron ta l b on e ; 7 , maxi l la rybone ; 8, tem pora l bone ; 9 , g rea te rw ing o f spheno id bone ; 10 , z ygo -ma tic p rocess o f tem pora l bon e ; 11 ,zygom at ic tem pora l su tu re ; 12 , z ygo -ma tic p rocess o f m axilla ; 13 , z ygo -ma tic m axil la ry su tu re ; 14 , orbitalsu rface o f m axilla ; 15 , infraorbitalfo ramen .

F ig . 2 .-A . Im p ingem en t o f tem -po ra l p rocess o f zygom a on corono idp ro cess o f m an d ib le as resu lt o f de -p re ssed zygom atic com p lex fractu reB and C . D ownw ard d is p lacem en t o ffro n ta l p rocess o f z ygom a and itsa ttache d la te ra l pa lpeb ra l ligam en tw ith separa tion o f zygom atic o fron ta lsu tu re . La te ra l c an thus o f eye lid an deyeba ll a re de pressed . O n upwardgaze . invo lved eyeba ll rem a in s fixeddue to in ca rce ra tion o f in fe rio r rectu sand in fe rio r ob liq ue m usc les be tweenbon y fractu re fra gm en ts o f o rb ita lfloo r. 0 , F ractu res o f in frao rb ita l p ro -cess, floo r o f o rb it, and la te ra l m axil-la ry s inus invo lv ing in frao rb ita l cana l,in frao rb ita l fo ram en , and nerve

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F ig 5 -D ownw ard and m ed ia l d is p lacem en t o f fron ta l p ro cess w ithsep ara tion o f zygom at ico fron ta l su tu re (open a rrow ) B lack a rrow p o in tsto frac tu re o f o rb ita l floo r

F ig . 3 .-Su bm en tove rtica l x-ray p ro jec tion o f zygom atic a rches show ing depressed fractu re o f tem pora l p ro cess o f zygom a tic b one (a r row)C lin ic a lly , pa tien t had lim ited m and ibu la r m o tion

ZYGOMATIC COMP LEX FR AC TURE 23 7

F ig 4 -Frac tu re o f in frao rb ita l p rocess resu lting in d isrup tion o fin frao rb ita l fo ram en and ste p de fo rm ity o f in frao rb ita t r im ( la rge opena r row) . Maxilla ry p rocess is no t f rac tu red . bu t its d isp la cem en t hasresu lted in frac tu re o f la te ra l m axilla ry s inus w a ll (sm a ll ope n a rrow ( an do pacific a tion o f s inus from hem orrh age C losed arrow po in ts to fractu reo f zygom atic a rch . C lin ica lly , pa tien t had pares thes ia o f in frao rb ita l ne rved is tr ibu tion and un ila te ra l ep is tax is

T he W ate rs p ro je c tio n typ ica lly d is p la ys a n opaquem ax illa ry s in us , w ith an as so c ia ted fra c tu re o f the la te ra lwa ll o f the in vo lve d m ax illa ry s in us (fig . 4 ). A n a ir-f lu idlev e l m ay be seen . Iso la te d o rb ita l f lo o r fra c tu res o r iso -la te d frac tu re s o f th e wa lls o f th e m ax illa ry s inu s , w ith o u tin vo lvem en t o f the p ro ces ses o f th e zygom a tic bone , ca n

a lso cau se un ila te ra l e p is tax is . F rac tu re s o f the m ax illao ccu rrin g be low th e le ve l o f the m ax illa ry p ro ce ss u sua llyin vo lve th e wa lls o f bo th m ax illa ry s inu se s , a s in th e LeFor ttype I frac tu re . B ila te ra l e p is tax is ra the r tha n un s la te ra lep is ta x is the n oc cu rs .

P are s th es ia o r A ne sth es ia in D is tr ibu tio n o fln fra o rb ita l N e rv e

T he in fra o rb ita l p rocess is a sh a rp ly p o in te d sp ike likep iec e o f bo ne pro jec ting m ed ia lly from th e bod y o f thezygom a and e x te nd in g unde r the o rb ita l ca v ity tow ard theno se . It is a ttach ed to the bod y o f th e m ax illa la te ra l to theo rb ita l floo r a t th e zygom a ticom ax illa ry s u tu re . It fo rm sth e la te ra l h a lf o f the in fra o rb ita l r im and a sm a ll pa rt o fth e an te rio r o rb ita l floo r ly in g an te ro la te ra l to th a t p a r t o fth e floo r o f th e o rb it fo rm ed from th e m ax illa . T h e tip o fth is p ro ce ss is in c lose con ta c t w ith th e in fra o rb ita l fo ra -men , wh ile its b a se is in con tac t w ith th e flo o r o f th e o rb itfo rm ed from the m ax illa .

F rac tu re s o f th is p ro ces s m ay in vo lve th e in frao rb ita lfo ram en , c ana l, a n d flo o r o f th e o rb it, d am ag in g the in fra -orb ita l ne rve ; th is re su lts in p a re s th es ia o r a ne sth es ia o fthe c heek , u ppe r lip , low e r eye lid . an d la te ra l n a sa l a re a onth e s id e o f th e in ju ry (fig s . 2 8 , 2D , a nd 4 ). W hen th isc lin ica l find ing is p resen t. th e W a te r s v iew o f th e fa c ia lbone s shou ld b e e va lu a te d fo r frac tu re s o f th e in fra o rb ita lr im e x ten d in g in to th e in fra o rb ita l fo ram en (fig s . 2D and4) a nd fo r fra c tu re inv o lvem en t o f th e o rb ita l f lo o r (fig . 5 ).

Iso la ted fra c tu res o f th e o rb ita l f lo o r, in frao rb ita l r im ,and an te rio r w a ll o f th e m ax illa ry s inu s m ay a lso p ro duceth is c lin ica l find in g .

Unequa l P up il H e ig h tsThe fro n ta l p ro ce ss p ro je c ts su pe rio rly from th e body

o f th e zygom a to fo rm th e la te ra l o rb ita l r im and a tta ch e sto th e fro n ta l bo ne a t the zygom a tico fron ta l su tu re . T hela te ra l p a lp eb ra l ligam en t (fig . 28) in se r ts o n the o rb ita l

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r im su rfa ce o f th is p roc ess abou t 1 3 mm be low th e lev e lo f th e zygom a tico fron ta l su tu re . D isp la cem en t o f th efron ta l p ro ce ss w ith sepa ra tion o f th e zygom atic o fro n ta lsu tu re (fig . 5 ) causes a dow nwa rd d isp la cem en t o r sagg ingo f th e la te ra l c an thu s o f th e eye lids a nd g lo be o f th e e ye .D epend ing upon m a la lignm en t o f v isua l a xes , d ip lop ia m ayor m ay no t occ u r [5 ] (f ig . 2B ). U nequa l p u p il he ig h ts w ith -ou t a lte ra tio n o f the v is ua l ax es is a d is tinc t c lin ica l f ind in gno t to be con fu sed w ith d ip lop ia . W hen th ese fin d in gs a rep re sen t, d isp la cem en t o f the fro n ta l p roce ss w ith w id en in go f the zygom a tic o fron ta l su tu re shou ld be looked fo r onth e W a te rs v iew (fig . 5 ) .

Decre ased E x tra ocu la r M usc le F unc tion w ith D ip lop iaThe orb ita l p ro ces s is a w id e fla t p os te rio r m ed ia l ex -

te n s io n o f th e fro n ta l p roce ss w h ich b le n ds in fe rio rly w iththe bod y o f the zygom a and in frao rb ita l p roc es s , fo rm ingthe la te ra l o rb ita l f loo r a nd la te ra l e dge o f th e in fra o rb ita lf iss u re . T he pa rt o f th is p ro ce ss lo ca ted above the in fra -o rb ita l f issu re a tta ch es to the g re a te r w in g o f th e spheno idbone a t th e zygom a tico spheno id su tu re . T h is fus ion o f theo rb ita l p roc ess w ith the g rea te r w in g o f the spheno id bonea t the zygom a ticospheno id su tu re resu lts in the fo rm ationo f a fla t p la te o f bone w h ich has an te r io r and pos te r io rsurface. The pos te rio r s u rfa ce fo rm s th e an te rio r w a ll o fthe tem po ra l fo ssa . T raum a to the chee k w h ich dep res se sthe zygom a tic bone inwa rd w ill d is p la ce the o rb ita l p rocessand in fra o rb ita l p ro ce ss m ed ia lly , ca us in g th em to fra c tu rethe la te ra l o rb ita l w a ll and floo r o f the o rb it. Th is fra c tu red is rup tio n o f th e bon y o rb it ca n p ro du ce d ip lo p ia e ith e r byp roduc ing edem a and hem o rrhage in the reg ion o f thee x trao cu la r m usc le s and nerv es [6 ] o r b y trap p ing th ee x trao cu la r m us c le s and ne rve s be tw een th e fra c tu redbon y fra gm en ts o f th e o rb ita l f loo r [7 ] ( figs . 2B -2D ) .

O rb ita l f lo o r fra c tu re s o ccu rre d in 35 o f 6 3 pa tie n ts w ithzygom atic com p lex fra c tu re s s tud ied by W isenbaugh [4 ].These w e re su rg ica lly p rov en b y exp lo ra tio n o f the o rb ita lflo o r, and a ll 35 pa tien ts requ ired su rg ica l co rre c tion .W hen d ip lo p ia is p re sen t, o rb ita l an d W ate rs v iew s shou ldbe e xam in ed fo r fra c tu res invo lv in g th e o rb ita l p ro ce ss ,g rea te r w in g o f the spheno id , in fra o rb ita l p ro ce ss , a ndo rb ita l flo o r. If fin d ings a re equ ivoca l, lam inog raphy o fthe o rb ita l flo o r shou ld be pe rfo rm ed .

S urg ic a l C on sid era tio nsThe su rg ica l p r in c ip le s in vo lved in the m anagem en t o f

zygom atic com p lex frac tu re s a re p rim arily re la te d to re -du c tio n o f th e fra c tu res . T he typ e o f s u rg ic a l ap p roa ch isb a sed on th e am oun t o f d isp lac em en t. T h e need fo r g oodra d io g ra ph ic e xam in a tion and in te rp re ta tio n is o b v io u s .It then becom es essen tia l fo r the su rgeon to de te rm ine

w he th e r trea tm en t ca n cons is t o f s im p le rep os itio n ing o fth e zygom atic com p le x o r if in te ross eou s fixa tion w illb e r eq uir ed .

In c lin ica l p rac tice , w e fin d th a t if th e segm en ts o f bo neinvo lv ed in the frac tu re a re la rg e and th e re is litt le com -m inu tio n o f the la te ra l w a ll o f th e m ax illa , s im p le rep o s i-t ion in g o fthe z ygom a tic com p le x in to its an a tom ica l p o s itio nby u tiliz ing an ex te rna l o r in te rna l app roach w ill frequentlya llow a s tab le re su lt. H ow ever, m ore fre q uen tly , o p en re -d uc tion w ith in te rn a l fixa tio n is re q u ired . T h is is a ccom -p lish e d by firs t s ta b liz ing th e fra c tu red z ygom a tico fro n ta ls u tu re so th a t on ce th e zygom a ha s been po s ition ed super-io rly , th e d is sec tio n to th e in fra o rb ita l r im a s we ll as thein te ro sseous w irin g a t the in fra o rb ita l r im frac tu re line a rele ss d if fic ul t.

B y e lev a ting the zygom a tic com p le x , the im p in g em en to n th e m asse te r a n d tem po ra lis m usc le and co ro no id p ro -cess o f the m and ib le w ill be reduced and the lim ita tion o fjaw m ovem en t e lim in a te d . U n ila te ra l ep is ta x is w ill p e rs is tu n til the m ax illa ry s in u s has had a sa tis fa c to ry le ng th o ftim e to c le a r. T h e u se o f de conge s tan ts is h e lp fu l. P a re s -th es ia and ane s th es ia o ve r th e d is tr ib u tio n o f th e in fra -o rb ita l n e rve freq uen tly rem a in po s to pe ra tive ly fo r som etim e . H ow eve r, rep o s itio n in g o f the bone so th a t the re isn o im p ing em en t o f th e in frao rb ita l n e rve w ill en h an ce itsre co ve ry . R educ tion o f th e z ygom a tic com p le x w ill e leva tethe la te ra l c an tha l lig am en t, re po s ition th e o rb ita l con ten ts ,and res to re the pup il to its no rm a l he igh t in the o rb ita lca v ity , th us e lim in a ting s ig n ifica n t s eque la . D ip lop ia fromsw e llin g o f th e m usc le w ill re so lve s low ly in 5 -1 4 da ys .D ip lop ia caused by en trapm en t o f the ex traocu la r m usc le sw ill u sua lly be e lim in a te d w ith re du c tio n o f the z ygom a ticcom plex fra c tu re .

ACKNOW L EDGMEN TW e th an k M s. B ill ie D uVa ll fo r a ss is tan ce in p repa rin g th is paper.

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