Journal Gunshot forensik

8/10/2019 Journal Gunshot forensik

1/6

68 5

R e v ie w A rtic le

G u n s h o t W o u n d s : 1 . B u lle ts , B a llis tic s , a n d M e c h a n is m s o f

In jury

J e rem y

J . H o ll er m an ,1 Mart in L . F a ck le r,2 D o u g la s M . C o Id w elI,3 a n d Y o ra m B e n -M e n a ch e m 4

T h e n a tu re a n d s e ve rity o f a b u lle t w o u n d d e p e n d o n th e

ch a ra c te ris tic s o f th e b u lle t a n d of th e tissu e s thro u g h w h ich it

tra v e ls . In a d d itio n to th e m a s s a n d v e lo c ity o f th e b u lle t, its

o rie n ta tio n an d w h e th e r it frag m e n ts o r d e fo rm s affe c t th e n a tu re

o f th e w ou n d . T w o m a jo r m e c h a n ism s o f w o u n d in g a re d e s cr ib e d :

c ru sh in g a n d s tre tch in g o f tis su e . U n d e rs ta n d in g th e m ec h a n ism s

b y w h ich b u lle ts d is rup t tissu e ca n h e lp p h ys ic ia n s to e va lu a te

a n d tre a t w ou n d s.

T h e ch a ra c te ris tics a n d se v e rity o f a g u n sh o t w o u n d a re

d e te rm in e d by th e d e s ig n o f th e w e a p o n a n d p ro je c tile , th e

in te rm e d ia te ta rg e ts th e p ro je c tile e n co u n te rs b e tw e e n th e

g u n m u zz le a n d th e b o d y , a n d th e se q u e n ce o f tiss ue s

e n co u n te re d a lo n g th e p ro je c tile p a th . A lth o u g h th e sk ill o f

th e p e rso n firin g th e w e ap o n a ffe c ts th e tra je c to ry , c h a n ce

a lso p la ys a ro le . If th e m iss ile p a th in c lu d e s a la rg e b o n e , o r

if th e p ro je c tile s tr ike s a b u tto n , be lt b u ck le , o r o th e r h a rd

o b je c t, th e s e ve n ty o f th e w o u n d o fte n in cre a se s [1 , 2 ]. T o

so m e e x ten t, w h e th e r th e b u lle t h its a p a rtic u la r w o u n d -

m o dify in g s tru c ture (su rfa c e o r a n a to m ic ) is a c h a n ce e v e nt.

F o r a n y p ro je c tile , if th e p a th in c lu d e s a cr itic a l a n a to m ic

s tru c tu re , th e re s u lt m a y b e fa ta l, ju s t a s if th e s tru c tu re h a d

b e e n s ta bb e d by a k n ife . In g e n e ra l, p ro je c tile w o u n d s a re

m o st se ve re w h e n th e m iss ile ya w s e a rly in its p a th th ro u g h

tiss u e , fra g m e n ts , is la rg e , a n d is tra ve lin g a t h ig h sp e e d .

C iv ilia n b u lle ts a re o ften m o re d am a g in g to tissu e th a n a re

m ilita ry b u lle ts fire d fro m ro u n d s oth e rw ise co n fig u re d id e n ti-

ca lly [1

,

3 ]. (A ro u n d is o n e c o m p le te u n it o f a m m u nitio n . T h is

in c lu d e s th e b u lle t, th e c artridge cas e, th e p o w d e r, an d th e

p rim er.) U n like m ilita ry b u lle ts , c iv il ia n b u lle ts a re n o t re q u ired

to h a v e a fu ll m e ta l ja c ke t (a m e ta l ja cke t co m p le te ly co ve r in g

th e b u lle t tip [3 ]) , a n d a re th e re fo re m u ch m o re like ly to d e fo rm

o r fra g m e n t in tissu e . B e ca u s e o f th is , w o u n d s p ro d u ce d b y

c iv ilia n h u n tin g r ifle s , s h o tg un s , a n d la rg e -ca lib e r ha n d g u n s

a re o fte n m o re se v e re th a n m ilita ry c o m b a t w o u n d s [3 ]. A n

e n e m y s o ld ie r w o u n d e d in w a r, w ho is s u ffic ie n tly d is a b le d to

n o lo n g e r fig h t b ut is n o t k ille d , u se s m o re e n e m y re s o u rce s

th a n o n e w h o is k ille d . In a d d itio n to th e lo ss o f th e so ld ie r o n

th e ba ttle fie ld , p e rs o n n e l a n d m a te ria l a re re q u ire d to c a re fo r

a n d fe e d th e w o u n d e d so ld ie r.

M e ch a n is m s o f W o u n d in g

B o th m iss ile a n d tis su e ch a ra c te ris tic s d e te rm in e th e n a tu re

o f th e w o u n d . M iss ile ch a rac te ris tic s a re p a rtly in h e re n t (m a ss ,

sh a p e , c o ns tru c tio n ) a n d a re p a rtly co n fe rre d b y th e w e a p o n

(lo n g itu d ina l a n d ro ta tion a l v e lo c ity ). T is su e ch a ra c te ris tic s

(e la s tic ity , d e n s ity , a n a to m ic re la tio n sh ip s) a ls o s tro n g ly a ffe c t

th e n a tu re o f th e w o u n d . T h e s e ve rity o f a b u lle t w o u nd is

in flu e n ce d b y th e bu lle ts o rien ta tio n d u rin g its flig h t th ro u gh

tis su e a n d b y w h e th er th e b u lle t fra g m e n ts [1 ] o r de fo rm s

(in to , fo r e x a m p le , th e ty p ica l m u sh ro o m sh a p e o f th e e x -

p a n d in g h o llo w -p o in t o r so ft-p o in t b u lle t).

R e ce ive d M a rc h 2 0 , 1 99 0 ; ac ce p te d a fte r re v is ion M ay 7 , 19 90 .

1 D e pa rtm en t o f R ad io lo gy an d M ed ica l Im ag ing , H en nep in C o un ty M e d ic a l C en te r and U n ive rs ity o f M inne so ta , 7 01 P ark A ve . S ., M inn eap o lis , M N 5 541 5 .

A d dre ss re p r in t re qu es ts to J . J . H olle rm an .

2 B a llis tics La bo ra to ry , M ilita ry T rau m a R e se arc h , Le tte rm a n A rm y In s titu te o f R es ea rch , S a n F ra nc isc o , C A 9 41 29 .

3 D e pa rtm en t o f R ad io logy , U n iv e rs ity o f W a sh ing to n S c hoo l o f M ed ic ine , S ea ttle , W A 98 10 5 .

D e pa rtm en t o f R ad io logy , U n iv e rs ity o f W a sh ing to n , H arbo rv ie w M e d ic a l C en te r, 32 5 N in th A ve . (Z A -65 ) , S ea ttle , W A 98 104 .

AJ R 1 5 5 : 6 8 5 - 6 9 0 , O ct o b er 19 90 03 61 -803 X /90 /1 5 54 -0 685 0 A m e rica n R oe n tg en R ay S o c ie ty


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N ote th a t b o th p erm an e n t cav ity a nd t em p or ar y c av ity a re m u ch la rg e r. A s is u su a l, t empor a r y a nd p erm an en t

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T w o m a jo r m e c h a n ism s o f w o u n d in g o cc ur: th e cru s h in g

o f th e tissu e s tru ck b y th e p ro je c tile ( fo rm in g th e p e rm a n e n t

c a v ity ), a n d th e ra d ia l s tre tch in g o f th e p ro je c tile p a th w a lls

( fo rm in g a te m p o ra ry ca v ity ) (F ig . 1).

In a d d itio n , a s o n ic p re ss u re w a ve p re ce d e s th e p ro je c tile

th ro u gh tiss u e . T he so n ic p re ssu re w a v e p la ys n o p a rt in

w o u n d in g . In a ir, th e speed o f so u n d is a p p ro x im a te ly 3 0 0 m /

se c ; in so ft tis su e , it is a p p ro x im a te ly 1 50 0 rn /se c . W h e n a

b u lle t e n te rs s o ft tis su e , th e s o n ic pre ss u re w a v e fo rm s a

h e m is p h e ric a l a rc a h e a d o f th e a d va n c in g b u lle t. T h e sh o rt-

live d so n ic p re s su re pu lse c re a te d m a y re a ch p res su re s o f u p

to 1 0 0 a tm (1 .0 1 x 1 O P a ). T h e du ra tio n o f th is p u lse is

a p p ro x im a te ly 2 se c [4 ]. R e s e a rch re p o rte d in 1 9 4 7 [5 ]

d e te rm in e d th a t th is s o n ic s h o ck w a ve h a s n o d a m a gin g

e ffe c t o n tissu e , a fin d in g s inc e co n firm e d b y c lin ica l ex p e ri-

e n c e w ith so n ic p re ssu re w a ve lith o tr ip s y , in w h ic h tissu e

re ce iv e s so n ic p res su re w a ve s tw o to th re e tim e s g re a te r

th a n th a t p ro d u c ed b y a su p e rso n ic r ifle b u lle t [6 ]. T h e s o n ic

p re ssu re w a ve m u s t n o t b e co n fu s e d w ith th e te m p o ra ry

c a v ity , w h ich is d isc u sse d la te r.

C rush ing o f T issue

A m iss ile c ru sh e s th e tiss ue it s trike s , th e reb y cre a tin g a

p e rm a n e n t w ou n d ch a n n e l (p e rm a ne n t ca v ity ) . Y a w is th e

ang le

b e t we e n

th e lo n g a x is o f th e b u lle t a n d its p a th o f flig h t.

If th e bu lle t is tra ve lin g w ith its p o in te d e n d fo rw a rd a n d its

lo n g a x is p a ra lle l to th e lo n g itu d in a l a x is o f fl ig h t (0 {17 6 }f ya w ),

it c ru sh e s a tu b e o f tiss u e n o g re a te r th a n its a p p ro x im a te

d ia m e te r. W h en th e b u lle t ya w s to 9 0 {1 7 6 },h e e n tire lon g a x is

o f th e b u lle t s trike s tiss u e , a n d th e a m o u n t c ru sh e d m a y b e

three tim e s g re a te r th a n a t 0 {1 7 6 }f ya w .

W he n str ik in g so ft tis su e w ith su ffic ie n t ve lo c ity , s o ft-p o in t

a n d h o llo w -p o in t b u lle ts d e fo rm in to a m u sh ro o m s h a p e . T h is

in c re a s es s u rfa c e a re a a n d w o u n d se ve rity . F o r m o st b ig -

g a m e h u n tin g , s u ch b u lle ts a re m a n d a te d b y la w . T h is is to

in c re a s e th e p ro b ab ility o f k il lin g q u ick ly , ra th e r th a n c re a tin g

a d isa b lin g b u t n o n le th a l w o u nd , a llow in g e s ca p e a n d p ro -

lo n g e d su ffe r in g . If th e m u sh ro o m e d d ia m ete r is 2 .5 tim e s

g re a te r th a n th e in itia l d ia m e te r o f th e b u lle t, th e a re a o f tis su e

c ru s h ed b y th e b u lle t is 6 .2 5 tim e s g re a te r th a n th e a m o u n t

th a t w o u ld h a v e been cru sh e d b y th e u n d e fo rm e d b u lle t.

B u lle t fra g m e n ta tio n a ls o in cre a se s th e vo lu m e o f tis su e

c rushed [1 , 7 ].

A fte r b u lle t fra g m e n ta tio n , s u rfa c e a re a is

in c re a s ed , a n d m u ch m o re tiss u e is c ru s h e d. F o r la rg e h a n d -

g u n (e .g ., .4 4 m a g n u m ) a n d rifle b u lle ts , the s trik in g o f bo n e

is o ne o f th e ca u se s o f e a r ly b u lle t fra g m e n ta tio n .

C o m m in u te d fra c tu re m a y b e c re a te d b y r ifle a n d la rg e

h a n d g u n b u lle ts s trik in g b o n e (F ig . 2 ). B o n e fra g m e n ts ca n

b ec om e s ec on da ry

m is s ile s , c ru sh in g tiss u e . M a n y h a n d g u n


3/6

F ig . 2 .-R ad io g ra p h s h o w s a s eve re ly d isru p tive b u lle t w o u n d o f le g .

G r o s s co m rn in u tio n o f frac tu res , m iss ile frag m en ta tio n , a n d se ve re so ft-

t iss u e d isru p t io n su g g es t e Ith er a la rg e-ca lib er h an d g u n , a rifle , o r a

s h o tg u n w ith la rg e-d ia m e ter s h o t s u ch as .0 0 b uck sh ot. T his w o u n d w as

d u e to a larg e h an d g u n (p ro b a b ly a .44 m ag n u m ). A c en ter -fire rifle o r

la rg e h an d g u n is m u c h m o re lik e ly to pr oduc e

severe ly

c omminu ted f rac -

tu re th a n is a sm alle r h an d g u n . S o ft -tis su e an d va sc u la r d a m a g e as so c i-

a te d w ith th ese fra c tu re s d e lay s h ea lin g an d in c re ase s co m plic a tio n s .

A J R :1 55 , O c tob e r 1 99 0

B U L L E T S , B A L L IS T IC S , A N D IN J U R Y

68 7

b u lle ts a re u n a b le to frag m e n t b o n e s ig n ific a n tly . W h e n a

la rg e b o n e is s tru ck , it is like ly th a t a b u lle t w ill e xp e n d its

w o u n d in g po te n tia l in th e p a tie n t a n d w ill n o t e x it.

B u lle t fra g m e n ts a n d s ec o n d a ry m iss ile s (b o n e fra g m e n ts ,

te e th , d e n ta l fil lin g s , co in s , e tc .) a re like ly to in crea s e th e

s e ve rity o f th e w ou n d . M u ltip le p e rfo ra tio n s w e a ke n tis su e

a n d c re a te fo c a l p o in ts fo r s tre s s (s tre ss ris e rs ), w h ic h a re

p a rticu la rly vu lne ra b le to th e e ffe c t o f tem p o ra ry ca v ita tio n

s tre tch [1 , 4] .

U n ja c ke te d le a d b u lle ts ca n n o t b e d riv e n fa s te r th a n a b o u t

2 0 0 0 ft/s e c (6 1 0 m /se c ) w ith o u t s o m e o f th e le a d s tr ip p in g

o ff in th e b a rre l o f th e g u n . T h is is a v o id e d if a ja c ke t m a d e

o f a h a rd e r m e ta l (su ch a s c o p p e r o r a co p p e r a llo y ), is u se d

to s u rro u n d th e le a d . T h e ja cke t o f a m ilita ry b u lle t c o m p le te ly

c o ve rs th e b u lle t tip (a fu ll m e ta l ja ck e t). C iv ilia n h o llo w -p o in t

a n d s oft-p o in t b u lle ts u su a lly h a v e a ja ck e t th a t su rro u n d s

p a rt o f th e b u lle t (a se m i- ja c ke te d b u lle t), lea v in g th e fron t

p o rtio n e xp o s e d so th a t it ca n e xp a n d .

T h e so ft-p o in t a n d h o llo w -p o in t b u lle ts o f c e n ter- fire rifle

ro u n d s u s u a lly d e fo rm in to a m us h ro o m s h a p e in tissu e ,

in c re a s in g th e v o lu m e o f tissu e cru sh e d . In co n tra s t, e ve n the

m a g n u m ve rs io n s o f so m e h a n d g un bu lle ts d e s ig n e d fo r

e x p a n s io n fa il to m u sh ro o m [8]. T h is is m o st lik e ly w ith sh o rt-

b a rre l h a n d g u ns . T h e s h o rte r th e b a rre l le n g th , th e s h o rte r

th e tim e a va ila b le fo r b u lle t a cc e le ra tio n b y th e e xp a n d in g

g a s e s cre a te d b y b u rn in g g u n p o w d e r. T h e re fo re , w h e n id e n -

tica l rou n d s a re fire d , th e g un w ith th e sh o rte r ba rre l p ro d u c e s

a lo w e r-ve lo c ity b u lle t. Its ve lo c ity m a y b e to o lo w to ind u c e

m us h ro o m in g a fte r im p a c t.

M us h ro o m -typ e e xp a n s io n is in te nd e d w ith c iv ilia n h o llo w -

p o in t a nd s o ft-p o in t b u lle ts . T h e y a ls o ca n fra g m en t. M ilita ry

fu ll-m e ta l- ja c ke t b u lle ts e ith e r s ta y in ta c t o r fra g m e n t; th e y d o

n o t m u sh ro o m . A lth o u gh th e M -1 9 3 m ilita ry b u lle t o f th e M 1 6

rifle fra g m e n ts in s o ft-tissu e w ith a c h a ra c ter is tic p a tte rn

d e p e n d in g o n ra n g e [9 , 1 0 ], o th e r fu ll-m e ta l- ja ck e t m ilita ry

b u lle ts , su c h a s th o se fire d fro m th e A K -4 7 , th e A K -7 4, a n d

th e N A T O 7 .6 2 -m m rifle (A m e rica n ve rs io n ), typ ica lly d o n o t

fra g m e n t u n le ss th e y s trike b o n e .

T em po ra ry C av ita tion T issue S tre tch

D u rin g flig h t, a b u lle t is s tab ilize d a g a in s t ya w b y th e s p in

im p a rte d to it b y th e sp in a l gro o ve s (r ifl in g ) in th e g u n b a rre l

[1 1 ]. T h e lo n g e r (a n d h e a v ie r) th e b u lle t in re la tio n to its

d ia m e te r, th e m o re ra p id ly it m u st b e ro ta te d to av o id s ig n ifi-

ca n t y a w in flig h t. T h e re fo re , a g u n b a rre l in te n d e d to fire a

h e a v ie r b u lle t h a s r iflin g th a t m a ke s a fu ll tu rn in fe w e r in c h e s

o f b a rre l le n g th th a n th e riflin g in a b a rre l in te n d e d fo r a

sh o rter, ligh te r b u lle t o f th e s a m e ca lib e r.

F ire d from a n a p p ro p ria te a n d w e ll-d e s ig n e d w e a p o n , a

b u lle t flie s in a ir w ith its n o se p o in te d fo rw a rd ; it ya w s o n ly 1

to 3 {1 76 }6 ]. Y a w o cc u rs a ro u n d the b u lle ts ce n te r o f m a ss [6 ].

In p o in te d r ifle b u lle ts , th e ce n te r o f m a ss is b e h in d th e

m id p o in t o f th e b u lle ts lo n g a x is . A lth o u g h th e b u lle ts m os t

n a tu ra lly s ta b le in -flig h t o r ie n ta tio n w o u ld b e w ith its h e a v ie s t

p a rt fo rw a rd , fo r a e ro d yn a m ica lly e ffic ie n t flig h t, it m u st fly

p oin t fo rw ard .

A lth o u g h th e b u lle ts sp in is a d e q u a te to s ta b ilize it a g a in s t

ya w in its flig h t th ro u g h a ir, it is n o t a d e q u a te to s ta b iliz e it in

its p a th th ro u g h tis su e , b e ca u se o f th e h ig he r d e n s ity o f th e

m e d iu m [1 2 ]. If it d o e s n o t d e fo rm , a p o in te d b u lle t e v e n tu a lly

ya w s to a b as e -fo rw ard p o s itio n (1 8 0 {1 7 6 }f ya w ). E x p a n d in g

b u lle ts lo s e th e p h ys ica l s tim u lu s to y aw , b e ca u se a fte r

m u sh ro o m in g th e ir h e a v ie s t p a rt is fo rw a rd .

A s a b u lle t p a ss e s th ro u g h 9 0 {1 7 6 }f ya w , it is c ru sh in g its

m a x im a l a m o u n t o f tis su e (u n le ss it fra g m e nts , w h ich w ill

c ru sh m o re ). It is s low e d d o w n ra p id ly , a s its w o u n d in g

p o te n tia l is u se d u p m o v in g tissu e ra d ia lly a w a y fro m its p a th .

T h is fo rce cre a tes th e te m p o ra ry ca v ity . T h is a sp e c t o f th e

w o u n d in g p ro c e ss is a n a lo g o u s to th e sp la sh o f a d ive r

e n te rin g th e w a te r.

If a d iv e r e n te rs th e w a te r ve ry s tra ig h t a n d p o in t fo rw a rd

(s im ila r to th e p o in t- fo rw a rd co n figu ra tio n o f a b u lle t a t ze ro

degrees

o f y a w ), th e sp la sh m a y b e m in im a l. If th e d ive r d o es

a b e lly - flo p (s im ila r to a b u lle t a t 9 0 {1 7 6 }f ya w ), a la rg e s p la sh

is in d u ce d . In tis su e , th is sp la s h , th e te m p o ra ry c a v ity , p ro -

d u ce s lo ca lize d b lu n t tra u m a (F ig . 3 ) [1 , 4] .

T h e m a x im a l s ize o f th e te m p o ra ry c a v ity o ccu rs se v e ra l

m ill ise c o n d s a fte r th e b u lle t ha s p a s se d th ro u g h th e tissu e

[1 1

].

B e ca u se

fo rce s fo llo w p a th s o f le as t re s is ta n ce , te rn -

porary

ca v ita tio n is like ly to be a sym m e tr ic a n d sp re a d o u t

th ro u g h tis su e p la n e s [4 ].

T h e te m p o ra ry c a v ity c a u se d by co m m o n h a n d g u n b u lle ts

is to o s m a ll to b e a s ig n ifica n t w o u n d in g fa c to r in a ll b u t th e

m o st se n s itive tiss u e s (b ra in a n d live r) [4 ]. C e n te r-fire rifle

b u lle ts a n d la rg e h a n d g u n b u lle ts (e .g ., .4 4 m a g n u m ) o fte n

in d u ce a la rg e te m p ora ry ca v ity (1 0 -2 5 c m [4-1 0 in .] d ia m e -

te r) in tis su e . T h is c a n b e a s ig n ifica n t w o u n d in g fa c to r,

d e p e n d in g o n th e c h ara c te r is tics o f th e tis su e in w h ich it

fo rm s [4 , 1 3].


4/6

B

F ig . 3.-A an d B , H igh -s pee d ra d io g ra ph s o f th ig h o f a c a t d u ring A )

a n d a fte r

B )

p as sa g e o f a 4 /3 2 -in . (3 .2 m m ) stee l sp h ere w ith im p a ct

v e lo c ity o f 3 20 0 ft/sec (975 rn /s ee ). S c ia tic n e rve o f ca ts th ig h m a d e

ra d io p a q u e w ith io d o b e n z en e . Im a g e s o b ta in ed w ith b e am p ara lle l to p a th

o f m i ss il e.

M ic ro s ec o n d ra d io g ra p h d u r in g p as sa g e

A )

s h o w s a nt er io r d is pl ac e-

m en t o f s c ia tic n erve b y tem p o ra ry ca vity . T is su es s u rro u n d in g p ath o f

p ro je c t ile a re un dergo ing b lu n t tra um a an d

t is su e s tr et ch

bec aus e of

te mp ora ry c av ity fo rm atio n.

R ad iog ra ph m a de Im m e d ia te ly a fte r s ho t B ) s ho ws p er ma ne nt cav ity

(w o u n d ch an n e l) is c o n s id erab ly s m a lle r th an tem p o ra ry c av ity .

Sciat ic

n e rv e is in its

u s u a l an a to m ic p o s itio n . N erv e a n d ve ss e l in ju ry fro m stre tc h

m ay h ave o cc u rred . (C o u rte sy o f L eo n ard D . H ea to n , Ja m e s B . C o a tes , Jr .,

a n d J am es C .

B ey er; re p rin te d w ith

p erm is s io n fro m W ou n d B a llis tic s ,

O ffic e o f the S urge on G en era l, D e p a rtm en t o f th e A rm y , 1 96 2 , p . 20 9 .)

68 8

H O L L E R M A N E T A L . A J R :1 55 , O cto be r 19 90

1

:.

.

,i

-

ii

. 4

.;

N e a r-w ate r-de n s ity , le ss e la s tic tiss u e (e .g ., b ra in , live r, o r

sp le en ), flu id -fi lle d o rg a n s ( in c lu d in g th e h e a rt, b la d d e r, o r

g a s tro in te s tin a l tra c t) , a n d d e n se tis su e (e .g ., b o n e ) m a y b e

d a m a g e d se ve re ly w h en a la rg e te m p o ra ry c a v ity co n ta c ts

th e m [1 1

].

M o re e la s tic tissu e (e .g ., sk e le ta l m u sc le ) a n d

lo w e r-d e n s ity e la s tic tis su e (e .g ., lu n g ) a re le ss affe c te d b y

th e fo rm a tio n of a te m p o ra ry c av ity [1 4 , 1 5 ]. B e ca u se o f th e se

tis su e d iffe re n c es , th e tra n sm itte d fo rce s o f te m p o ra ry ca v i-

ta tio n c a u se d b y a b u lle t tra v e lin g 8 00 -9 5 0 m /se c ca n ca u se

a m o re se ve re p u lm o na ry co n tu s io n w h e n th e b u lle t tra ve rse s

th e ch e s t w a ll m u sc u la tu re th a n th e p u lm o n a ry co n tu s io n th a t

w o u ld h a ve o c cu rre d h a d th e sa m e b u lle t p a sse d d ire c tly

th ro u g h th e lu n g [3 , 1 5 , 1 6 ].

A lth o u g h fo rm a tio n o f a la rg e te m p o ra ry ca v ity o fte n h a s

d e va s ta tin g e ffe c ts in th e b ra in o r liv e r, its e ffe c t in w o u n d s

o f th e e x tre m itie s h a s fre q u e n tly b e e n ex a g g e ra te d in a rtic le s

a b o u t w o u n d b a llis tics [4 , 6 , 1 7 ]. F ra c tu re o f la rg e b o n e s n o t

h it b y th e b u lle t a n d te a rin g o f m a jo r ve ss e ls o r n e rve s b y th e

te m p o ra ry ca v ity a re o fte n m e n tio n e d in th e lite ra tu re (e .g .,

D e M uth [3 ]), b u t a re ra re in c lin ic a l e x p e rie n c e . T h is in c lu d e s

a sys te m a tic re v ie w o f 1 4 0 0 rifle w o u n ds su s ta in e d in th e

V ie tn a m e se W a r a n d an a lyze d in th e W o u n d D a ta a n d M u n i-

tio n s E ffe c tive n e ss T e a m (W D M E T ) s tu d y (B e lla m y R F , p e r-

so n a l co m m u n ic a tio n ). M o st o f th e p e rm a n e n t d a m a g e in

w o u n d s o f th e e x tre m itie s is th e re s u lt o f s tru c tu re s b e in g h it

b y th e in ta c t b u lle t, bu lle t fra g m e n ts , o r se c o n d a ry m iss ile s .

A s in a ll b lu n t tra u m a , sh e a r fo rc e s d e ve lop a n d te ar s tru c-

tu re s a t p o in ts w h e re o n e s id e is fixe d a n d th e o th e r s id e is

fre e to m o ve . T h e te m p ora ry c a v ity is n o e xce p tio n . In th e

u n lik e ly e v e n t th a t the b lu n t tra u m a o f th e te m p o ra ry ca v ity

te a rs a v e sse l w a ll, th is is p a rticu la r ly like ly to o cc u r a t th e

ve ss el or ig in .

B a llis tic P ro p erties a n d th e W o u n d P ro d u c ed

R e c e n t c o n tro lle d a n im a l e xp e rim e n ts w ith m ilita ry rifle

b u lle ts [1 8 ] h a ve c le a r ly d isp ro v e d th e a ss e rtio n th a t a ll tis su e

e xp o se d to te m p o ra ry ca v ita tio n is d e s tro y e d . T h es e s tu d ie s

a lso sh o w th a t n ot o n ly d o e s th e 1 4-c m -d ia m e te r te m p o rary

ca v ity p ro d u ce d b y the A K -7 4 a ss a u lt rifle n o t d e s tro y a g re a t

a m o u n t o f m u sc le , b u t th e s iza b le s te lla te e x it w o u n d it

ca u se s in th e u n co m p lica te d th ig h w o u n d e n su re s e xc e lle n t

w o u n d d ra in a g e , w h ich a ss is ts h e a lin g [1 4 , 1 8, 1 9]. T h is is

co n s is te n t w ith th e p a th o p h ys io lo g y of w o u n d h e a lin g a n d

th e h is to ry o f th e tre a tm e n t o f w o u n d s re ce iv e d in w a r [1 8 ,

1 9]. A h is to ry th a t th e w o u n d w a s ca u se d b y a h ig h -ve lo c ity

b u lle t d o e s no t m a n d a te ra d ica l e xc is io n o f th e w ou n d p a th

[4 , 6 , 1 3 , 1 4 , 1 9 -2 1 ].

T h e c h a ra c te ris tics o f th e w ou n d e d tissu e , th e th ick n e ss of

th e b o d y p a rt, th e p o in t in th e p a th of th e b u lle t a t w h ic h ya w

o r fra g m e n ta tio n o ccu rs , a n d o th e r fa c to rs s tro n g ly in flu e n ce

th e w o u nd p rod u c e d . B u lle ts o f e q u a l w o u n d in g p o te n tia l m a y

p ro d u ce w o u n d s o f q u ite d iffe re n t se ve r ity , d e p e n d in g o n

w h ich tis su e s th e y tra v e rse . T h e h e a v ier, s lo w e r b u lle t

c ru sh e s m o re tiss u e b u t in d u ce s le s s te m p o ra ry c a v ita tion .

M o s t o f th e w o u n d ing p o te n tia l o f th e lig h te r, fa s te r b u lle t is

like ly to b e u s e d u p fo rm in g a la rg e r te m p o ra ry ca v ity , b u t

th is b u lle t le a v e s a sm a lle r p e rm a n e n t c a v ity . T h e h e a v ie r,

s lo w e r b u lle t ca u se s a m o re se v e re w o u n d in e la s tic tis su e

th a n th e lig h te r, fa s te r b u lle t, w h ich u s e s u p m u c h o f its

p ote n tia l p ro d uc in g tiss u e s tre tc h (te m p ora ry ca v ita tio n ). T h is

tiss u e s tre tch m a y b e a b s o rb e d w ith little o r n o ill e ffe c t b y

e la s tic tis su e su ch a s lu n g o r m u sc le . In n o n e la s tic tissu e ,

su ch a s live r o r b ra in , th e te m p o ra ry c a v ity p ro d u ce d b y th e

lig h te r, fa s te r b u lle t ca n pro d u ce a m o re se ve re w ou n d .

E xp e rim e n ts w ith b a llis tic g e la tin (w h ich d u p lic a te s th e p ro -

je c tile d e fo rm a tio n a n d p e n e tra tio n d e p th o fliv in g a n im a l m u s -

c le [1 3 ]) h a ve sh o w n th a t m o st fu ll-m e ta l-ja cke te d rifle b u lle ts

ya w s ig n ifica n tly o n ly a t tiss ue d e p th s g re a te r th a n th e d i-

a m e te r o f h u m a n e xtre m itie s [1 0 ]. In th e firs t 1 2 cm (th e

a ve ra g e th ic kn e ss o f a n a d u lt h u m a n th ig h ) o f a so ft- tis su e

w o u n d p a th , th ere is o fte n little o r n o d iffe re n c e b e tw e e n th e

w o u n d in g e ffe c ts o f lo w - a n d h ig h -v e lo c ity b u lle ts w h e n th e

h ig h -v e lo c ity b u lle t is o f th e m ilita ry fu ll-m e ta l-ja cke t typ e [4 ,

1 0 ]. T h is is p a rticu la r ly tru e o f th e re la tive ly h e a v ie r m ilita ry

rifle b u lle ts , su c h a s th o se fire d b y th e A K -4 7 a n d N A T O 7 .6 2 -

m m (A m e ric a n ve rs ion ) r ifle s [4 ]. A w o u n d o f a n e x tre m ity

ca u se d b y a n A K -4 7 b u lle t th a t d o e s n o t h it b o n e is o fte n


5/6

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.

V e l -Us

lu.s.

w %- s e s , ( L4 e .

H

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\ i /4 j$ p l

. . . C aV Ity

-

.

S. SI Is I I IS II Is Is

0 c m 5 1 0 1 5 $1 $0 $ 4 4 0

4 $ 1$

A

-

B

A JR :1 55 , O ct ob er1 99 0

B U L L E T S , B A L L IS T IC S , A N D IN JU R Y 6 89

1 . F ac k le r M L, S un nc ha k JS , M a lin ow sk i J A , B ow en R E . B u lle t frag m e n ta tio n :

a m ajo r ca us e o f tiss ue d is ru p tion . J T ra um a 1984 ;24 :35 - 39

F ig . 4 .-A a n d B , T h es e w o u n d p ro file s illu s tra te u se o f b a llis t ic p rin c ip les fo r w o u n d d es ig n . W o u n d p ro f ile s o f A K -47 A ) an d

A K - 7 4

B )

bul le ts

in

b a llis tic g e la tin are p re se n te d . A K -4 7 h a s

been

s ta n d a rd m ilita ry rifle o f S o v ie t b lo c b u t is

be ing

rep lac ed w ith

A K-7 4. A K-4 7 f i res

a

7 .89 -g

f u l l - m et a l - j acket

(F M C ) b u lle t 7 .6 2 m m In d iam eter a t a m u zz le ve lo c ity o f 71 3 rn /se c (2 34 0 ft/sec ). A K -7 4 f ire s a 5 .45 -m m , 3 .4 -g F M C b u lle t a t 93 5 rn /se c (3 06 6 ft/e ec ).

AK- 74

bul le t Is

d e s ig n e d to ya w ea rlie r in

its

w o u n d p a th th an A K -4 7 b u lle t d o es (s ee tex t).

Ex t r emi t y

w o u n d s fro m A K -7 4 ca n b e exp ec te d to b e m u c h

m o re sev ere th an th o se fro m A K -47 . T h is is es p e c ia lly t rue fo r w o u n d p a th s i n e x tr em i ti e s th at a re e ntire ly th ro ugh so ft tis su e a n d d o no t In c lu de a la rge

bone .

s im ila r to a h a n d g u n b u lle t w o u n d . A so ft- o r h o llo w -p o in t

b u lle t fire d fro m a c iv ilia n rifle d e fo rm s so o n a fte r en te r in g

tiss u e a n d p ro d u ce s a m u ch m o re se ve re ex tre m ity w o u n d .

C o m p a re th e firs t 1 2 cm o f th e w o u n d p ro file o f th e .2 2 lon g -

r ifle ro u n d in F ig u re 1 w ith th e w o u n d p ro file o f th e A K -47

ro u n d in F ig u re 4 . If a h ig h -v e lo c ity , h e a vy b u lle t d o e s n o t

d efo rm , fra g m e n t, o r h it a b o n e , it m a y e x it a n e x tre m ity w ith

m u ch o f its w o un d in g p o te n tia l u n sp e n t. T h e se sa m e b u lle ts

a re o fte n le th a l in ch e s t o r a b d o m in a l w o u n d s b e ca u s e th e

tru n k is th ic ke r th a n a n e xtre m ity a n d a llo w s th e b u lle t a

s u ffic ie n tly lo n g p a th th ro u g h tissu e to y a w . N o te th a t m a x im a l

tem p o ra ry ca v ita tio n in d u ce d b y th e A K -4 7 b u lle t (F ig . 4 A )

d ur in g th e firs t cyc le o f b u lle t y a w is a t a tis su e d e p th o f 2 8

cm , m u ch g rea te r th a n th e d ia m e te r o f a hu m a n e xtre m ity .

T h e se co n d c yc le o f b u lle t ya w o cc u rs a t a d e p th to o gre a t

to b e o f s ig n ifica n ce in m o st w o u n d p a th s in h u m a n s.

T h e A K -7 4 b u lle t (F ig . 4 B ) is lig h te r th a n th e A K -4 7 b u lle t

a nd is in te rn a lly c o n s tru c te d to ca u se ea rly ya w . It c au s e s its

m a x im a l te m p o rary c av ity a t a tiss u e d e p th o f 1 1 c m . E xtre m -

ity w o u n d s fro m th e A K -7 4 ca n b e e xp e c ted to b e m u ch m o re

se ve re th a n th o s e fro m th e A K -4 7 [9 , 2 2 ]. T h e lig h te r, sm a lle r

ro u n d a llo w s a s o ld ie r to c a rry m a n y m o re ro u n d s o f a m m u -

n itio n . T h is w a s th e p rim a ry m o tiva tio n fo r d e ve lo p m e n t o f

the M l 6 a n d th e A K -7 4 [4 ].

F ig u re 1 sh o w s th a t ca lib e r (b u lle t d ia m e te r in h un d re d th s

o f a n in ch ) is o n ly o n e in d ica to r o f w o u n d in g p o te n tia l, a n d it

is n o t a v e ry g o o d o n e . A lth o u g h th e .2 2 lo n g -rifle b u lle t a n d

the M -1 6 b u lle t a re s im ila r in d ia m e te r (c a lib e r) , th e M l 6 b u lle t

is h e a v ie r (3 .6 vs 2 .7 g fo r th e .2 2 lo n g -rifle b u lle t) , m a in ly

b ec a u se th e M l 6 b u lle t is lo n g e r. E a ch b u lle t is se e n pro trud -

in g fro m th e e n d o f its ca rtrid g e ca se . T h e b u lle t is th e p o rtio n

o f th e ro u n d th a t lea v e s th e e n d o f th e g u n b a rre l a fte r firin g .

B e ca u se o f its m u ch h ig h e r ve lo c ity (3 0 9 4 ft/se c [9 4 3 m /

se c ], a s o p p o se d to 1 1 2 2 ft/se c [3 42 m /se c ] fo r th e .2 2 lon g -

rifle b u lle t) , b e c a us e it fra g m e n ts in tissu e , a n d b e c a u se o f its

g rea te r b u lle t m a ss , th e M l 6 b u lle t ca u se s a m u ch m o re

se ve re w o u n d . N o te th a t b o th th e p e rm a n e n t c a v ity a nd th e

te m p o ra ry c a v ity a re m u c h la rg e r. A s is u su a l, th e te m p o ra ry

a n d p e rm a n e n t c a v itie s o f th e .2 2 lo n g -r ifle b u lle t a re la rg e s t

w h e n th e b u lle t is a t 9 0 {1 7 6 }f y a w . N o te a ls o th a t th e la rg e

te m p o ra ry a n d p e rm a n e n t ca v itie s fo rm e d b y th e M l 6 b u lle t

o c cu r m a in ly fro m 1 1 to 3 0 cm d e e p in tissu e . T h e b u lle t ha s

its h ig he s t ve lo c ity w h e n it e n te rs th e tiss u e , b u t fo rm s a

sm a ll w o u n d ch a n n e l a t tha t p o in t. O n ly w h e n it fra gm e n ts o r

ya w s to 9 0 {1 7 6 }s its se ve re w o un d in g e ffe c t re a lize d . A t th a t

p o in t it is tra ve lin g s lo w e r. B u lle t ve lo c ity , th e n , is o n ly o ne

fa c to r in w o u n d in g [7 , 2 0 , 23 ].

B u lle ts a re n o t s te r il ize d b y th e h e a t o f fir in g . T he y ca n

c a rry b a c te r ia fro m th e b o d y su rfac e o r b o d y o rg a n s , in c lu d in g

a p e n e tra te d co lo n , d e e p in to th e w o u n d [1 2 , 2 4 ].

C onc l us i ons

U n d e rs ta n d in g th e m e c h a n ism s b y w h ich p e n e tra tin g p ro -

je c tile s d is ru p t tis su e ca n a ss is t th e p h ys ic ia n in e v a lu a tin g

a n d trea tin g th e w o u n d in a ra tio n a l m a n n e r. B o th m iss ile a nd

tissu e ch a ra c te ris tic s d e te rm in e th e n a tu re o f th e w o u n d .

T w o m a jo r m e ch a n is m s o f w o u n d in g e x is t: c ru sh in g a nd

s tre tch in g o f tiss u e . T h e e la s tic ity a n d d e n s ity o f a tiss u e a nd

th e th ic kn e ss o f th e b o d y p a rt w o u n d e d s tro n g ly a ffec t th e

w o u n d p ro d uc e d . M iss ile m a ss , co n s tru c tio n , te n d en c y to

fra g m e n t o r ya w , a n d ve lo c ity a re k ey fa c to rs in d e te rm in in g

th e w o u n d in g p o te n tia l o f a m iss ile . V e lo c ity o fte n d o m in a te s

d iscu s s io n s o f w o u n d b a llis tics ; h o w e ve r, a b u lle t c a n in flic t

m o re le th a l d a m a g e to tissu e b y fra g m e n ta tio n a n d y a w th a n

b y h ig h v e lo c ity .

A C K N O W L E D G M E N T S

W e g ra te fu lly a ckn o w le d g e th e a ss is ta n c e o f T o n i W illia m s a n d

L aura W a lsh fo r a id in lite ra tu re re tr ie va l a n d J a m es K a u fm a n n fo r a

c are fu l re ad in g o f th e m an usc rip t.

R E F E R E N C E S


6/6

69 0

H O L L E R M A N E T A L .

A JR :15 5 , O cto be r 1 99 0

2 . D a h I E , B c 0 . C ritica l p o ly trau m atiz a t ion o f a p a tien t by a low -v e lo c ity

gu nsh ot: ca se re po rt. A cta C h ir S can d 1978; 144: 537- 540

3 . D e M u th W E Jr . B u lle t v e lo c ity an d de s ig n as d e te rm ina n ts o f w o un d in g

ca pa bil ity : a n e xp erim en ta l s tu dy . J T ra um a 1966; 6 : 222- 232

4 . B o w e n T E , B e llam y R F . E m e rg en cy w a r su rge ry : se co nd U n ited S ta te s

re v is ion o f the e m e rg en cy w a r su rge ry N A TO han db oo k, 2n d ed . W as h in g-

to n , D C : U n ited S ta tes D ep artm e n t o f D e fen se , U n ite d S ta tes G o ve rnm en t

P r in ting O ff ice , 1 98 8 :1 3 -3 4 , 2 30 -23 8

5 . H arv ey E N , K o rrIM , O s te r G , M c M illen JH . S ec ond ary d am ag e in w oun d ing

du e to p res su re c ha ng es a cc om pa ny ing the p as sag e o f h igh ve loc ity

m is s i les . Surge r y 1 94 7;2 1 :2 18 -2 39

6 . F a ck le r M L. W oun d b a ll is tics : a rev iew o f c om mo n m isc on cep tio ns . J AMA

1988 ;259 :2730- 2736

7 . W ang Z G , F e ng J U u Y Q . P a tho m o rp ho log ica l ob se rva tio ns o f g un sh o t

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