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    Trauma Analysis in PaleopathologyNANCY C . LOVELLDepartm ent of Anth ropology, U ni versity of Alberta,

    Ed m o n t o n , AB T 6 G 2 H 4 , C a n a d a

    K E Y W O R D S fra cture; dislocation; violence; head injury

    A B S T R A C T This paper reviews the mechanisms of injury a nd the types offra ctures tha t most commonly affect th e huma n skeleton, presents descriptiveprot oc ol s for c rani al and post c rani al f rac t ures adapt ed from c l i ni c al andforensic medicine, and summa rizes an a tomica lly the injuries most likely to befound in archaeological skeletons along with their most common causes andcomplicat ions. Mecha nisms of injury are categorized as direct an d indirecttrauma, stress, and fracture that occurs secondary to pathology. These are

    considered to be the proximate, or most direct, causes of injury and they areinfluenced by intrinsic biological factors such as age and sex, a nd extrinsicenvironmenta l factors, both physical a nd sociocultural , th at may be thoughtof as the ultimate, or remote, causes of injury. Interpersonal conflict may beone of those causes but the skeletal evidence itself is rarely conclusive andmust therefore be evalua ted in its individua l, populationa l, sociocultura l, andphysical context . A cautiona ry ta le regarding pa rry fractures is presented asa n illust ra tion. Yrbk P hys Anth ropol 40:139170, 1997. 1997 Wiley-L iss, I nc.

    Tr a u m a m a y b e d efi n e d m a n y w a y s b utconventiona l ly is understood to r efer to a ni njury t o l i v i ng t i ssue t hat i s c aused b y aforce or mechanism extrinsic to the body.The an at omical importance and sociocul-t ural i m pl icat i ons of t raum a i n a nt i quit ylong have been recognized and the descrip-t i on of t ra um a i n hum an skel et a l rem ai nsand t he i dent i fic at i on and com pari son oftra uma pa tterns a mong ancient populat ionst herefore hav e a l engt hy hi st ory. A s t hediscipline of palaeopathology has developed,the objectives of traumatic injury analysishave shifted from a focus on t he identifica-tion a nd description of the ea rl iest a nd t hemost unusual pathological specimens to theinterpreta tion of the social, cultura l, or envi-

    ronmenta l causes of tra umat ic injury; theirrelationship to biological variables, such assex and age, tha t ma y ha ve social or culturalrel ev anc e; and t hei r t em poral and spat i a lvar iat ion. Thus, interpreta tions of the causeof tra uma in ant iquity range from inter-an dintra group conflict (e.g., Angel, 1974; Ha m-perl, 1967; J anssens, 1970; J urmain, 1991;

    Li st on and Ba ker, 1996; Sherm is , 1984;St ewa rt , 1974; Wa lker, 1989; Wood-J ones,1910; Zivanovic, 1982; an d others ) to environ-mental ly or occupational ly faci l i tated mis-adventure and accident (e.g., Angel, 1974;B urrell et a l . , 1986; Cybulski, 1992; Gra ueran d Roberts , 1996; Kelley a nd Angel, 1987;Lovejoy and Heiple, 1981; Wells, 1964; andothers). Although great advances have beenm ade i n pal eopat hological di agnosi s andinterpreta t ion in recent years, inconsisten-cies in descriptions and interpretat ions oft r a u m a i n t h e l it e ra t u r e , p a r t i cu la r l y a sthey a ffect our understa nding of the na turean d extent of interpersonal violence in an tiq-uity, have made i t di ff icult to compare theresul t s of di fferent s t udies and t o ac cept

    with confi dence some conclusions. The pur-pose of this paper, therefore, is to reviewt ypes of f rac t ures and t he m ec hani sm s ofinjury, critiq ue protocols for fra cture descrip-tion, an d consider t he problems of interpret-ing t he cau ses of injury. Although a n impor-t a n t s ou r ce of d a t a f or t h e s t u dy of t h ehistory of medicine, a discussion of skeleta l

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    i ndi cat ors of surgical pract i ce and ot hermedica l intervent ion is beyond th e scope ofthis pa per.

    Scholars have cat egorized t ra umat ic inju-r ie s i n a v a r ie t y of w a y s (Ta b le 1), b utgenerally refer to both accidental and inten-tional tra uma, t he former usua l ly includingmost fra ctures and dislocations a nd the lat -ter usual ly including examples of surgicalintervention and w eapon wounds. I t ma y bemore prudent, however, to fi rst sort injuriesaccording to their predominant characteris-tic, either f r a c t u r e 1 (an y break in the conti-nuity of a bone) or di slocation (the displace-ment of one or more bones at a joint), rat hert han t o c l ass i fy i njuri es i n a m anner t hatimplies ca usa tion or intent .

    DISLOCATIONS

    Tra uma tic injuries to joints m ay result inpartial or complete dislocations. A disloca-tion, or luxat ion, occurs when the ar t icularsurfa ces of a joint a re tota lly displa ced fromone another. Asubluxation results when theart i c ul ar surfac es are part i a l ly di splac edbut do reta in some conta ct. Although disloca-tions and subluxa tions may be congenita l orspontaneous in origin, they are most com-monly ca used by tra uma a nd in such cases it

    is not uncommon for t he joint displacement

    to be associated with a fracture. Since dis-placement cannot occur w ithout dama ge tothe joint capsule a nd l igaments, complica-t ions such a s t he ossifi cation of membrane,l igam ent , a nd t endon at t ac hm ent s t o b onema y ensue. Persistent inst a bility of the jointalso may r esult, part icular ly in the shoulderand ankle, a l though this complicat ion can-not b e easil y i dent i fied i n arc haeol ogi calskeleta l remains. Osteoart hritis is one of themore common, and recognizable, complica-t ions a nd results from da mage to the a rt icu-lar cartilage itself or from prolonged incon-gruence of the joint surfaces.

    For joint displacements to be recognizablein dry bone the injury must have occurredsome time before the death of an individuala nd rem a ined unr educed (i.e., not set) longenough for bone modificat ions t o ta ke pla ce.Som e di s locat i ons, such as of t he di gi t s ,usual ly can be relat ively quickly a nd ea si lyreduced (but see D reier, 1992), wh ile oth ers,such as of the vertebra e, may cause immedi-at e death. In ei ther case no evidence of theinjury will be observable in archaeologicalskeletons.

    Dislocations tend to be more frequent inyoung an d middle-a ged ad ults, since in sub-ad ults a similar force instea d causes epiphy-

    seal separat i on a nd i n older a dult s causesfracture of osteoporotic bones. The glenohu-meral joint is a common site of dislocation,the sha l lowness of the shoulder joint mak-ing i t part icularly susceptible to displace-ment. Tra uma tic dislocation of the femoralhead from the acetabulum, in contrast , re-qui res considerab le force and t hi s s it e i s

    1 Infracture and infraction are alternative terms for frac-ture, particularly undisplaced fra ctures, according t o medicaldictionaries (e.g., Stedman , 1982). Although ra rely used inpaleopathology, these terms ma y be seen in the l i terature w ith adifferent meaning: infra ction, for example, has been defined asan incomplete fracture. In the interests of developing clear andstandard terminology, these al ternative terms are not used inthis review.

    TAB LE 1. Vari ation in the categori zation of traum atic inju ri es by different authors

    Knowles (1983) Merbs (1989a)Ortner and

    Put schar (1981) Steinbock (1976)Roberts an d

    Manchester (1995) This study

    Fr a ct ur es F ra ct ures F ra ct ures Fr a ct ur es F ra ct ures3 Fractures4

    D isloca tion s D isloca tion s D isloca tion s D isloca tion s D isloca tion s D isloca tion sTrephinat ion a nd

    amputat ionS ur ger y Tr eph in at ion S ha rp I nst rumen ts2 Osteochondritis

    dissecansWe a p on w o u n ds We a p on w o u n ds We a p on w o u n ds G r o w t h a r r e s t l in e sE xost oses S ca lpin g S ca lpin g C rush in g injur iesS c h mor l s n od e s D e n t a l t r a u m a 1 Deformation 1

    Osteochondritisdissecans

    Pregnancy-related

    1Includes cranial deformation, filing of teeth, and other modifications performed for aesthetic purposes.2Includes surgery a nd wea pon wounds.3Includes piercing injuries cau sed by knife and sw ord cuts, scalping, an d projectile points (i.e., surgery a nd wea pon wounds).4Includes piercing injuries caused by knife a nd sword cuts, sca lping, and projectile points (i.e., surgery a nd wea pon wounds), and crushfractures caused by foot binding and by cranial binding and fl att ening.

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    more commonly associated with congenitaldislocations.

    FRACTURES

    A fracture consists of an incomplete orcomplete break in the continuity of a bone.The most common types of fract ures, such a stransverse, spiral , obl ique, and crush frac-tures, result from direct or indirect trauma.Two a dditional t ypes of fractur es, those re-sult ing from stress and those secondary to

    pathology, are less common and have dis-t i nct e t iol ogies. Frac t ure t ypes and t heirassoci at ed m echani sm s of i njury are re-viewed below (a nd summa rized in Ta ble 2),followed by discussions of fracture healingan d complicat ions.2

    Mechanisms of injury and typesof fractures

    D i r ec t t r a u m a . When a break occurs att he poi nt o f i m pac t i t i s referred t o as adirect trauma injury (Miller and Miller, 1979)a n d t h e r e s u l t i n g f r a c t u r e m a y b e t r a n s -verse, penetra t ing, comminuted, or crush

    (Fig. 1). A tra nsverse fra cture results fromf or ce a p pl ie d i n, a n d a p pe a r s a s , a l in eperpendicular t o the longitud inal a xis of thebone. Clinical ly, this injury often results

    from a ha rd kick to the shin a nd is often seenam ong soccer pla yers. Typica lly, t ra nsversefrac t ures are c aused b y a rel a t i v el y sm al lforce delivered to a s ma ll area .

    P a rt i a l or com plet e penet rat i on of t hebone cortex by cutting, piercing, drilling, orscraping, such as the excision of pieces ofcrania l vault bones in the practice of trephi-na tion, or the a mputa tion of a limb segmentis classed as a direct tr aum a injury. Penetra t-ing fractur es typica lly are caused by applica -

    t i on of a l a r g e for ce t o a s m a ll a r ea . I narcha eological contexts, penetra t ion couldbe caused by a projectile point, t he blad e ofan axe or sw ord, or a m usket b al l ( Bl ai r ,1983; Butler, 1971). Wounds from arrow orspear poi nt s of t en c an b e i dent i fied w i t hcertainty only i f the point remains embed-ded i n t he b one and heal i ng w oul d not b eevident i f such wounds were l inked to thedeat h of the individua l. The huma n rema insin ma ny historic cemeteries show the t rau-m at i c result s of confl i ct s w i t h b ull et s andother projectiles (e.g., G ill, 1994; L a rsen et

    a l., 1996; Ow sley et a l., 1991). Ea rly ca ses ofpenetrat ing projecti le w ounds can be ex-pected to sh ow subsequent infection a nd/orpronounced deformity in th e absence of sta-bil izat ion or rest of the injured part . Somepenetrat ing fractures may also be commi-nuted, which occurs when the bone is brokenin more than two pieces. In cl inical cases,

    2The information provided here has been compiled from avariety of sources, including Adams (1987), Apley and Solomon(1992), Gust ilo (1991), Har kess a nd R am sey (1991), a nd S chultz(1990).

    TAB LE 2. Summ ary of mechani sms of in jur y and associated types of fractur es

    Mech a n ism of I njury Type of fr a ct ur e C ommen t s

    D ir ect t ra u ma P en et ra t in g P a r tia l or com plet e pen et ra t ion of bon e cor texC o mm i n ut e d B o n e i s b r ok en i n m or e t h a n t w o p ie ce s ; m os t co mm on i n l on g

    bone diaphysesTr a n s v e rs e F or ce a p p li ed i n a l in e p er p en d i cu l a r t o l on g a x i s o f t h e b on eC ru sh Most com mon in ca ncellous bon e

    D e pr es s ion C r u sh in g f or ce on on e s id e of t h e b on eC om pr es s ion C r u sh in g f or ce on b ot h s id esP r es su re F or ce a pplied t o g row in g b on e

    I nd ir ect t ra u ma S pir a l R ot a t ion a l a n d lon git ud in a l s tr es s on lon g a xis ; of ten con fu sedwith oblique fracture

    O bl iq u e R ot a t i on a l a n d a n g u la r s t r es s on l on g a x is ; of t en con f us ed w i t hspiral fracture

    Torus/greenstick Bend ing of the bone due to longitudinal compression; common inchildren

    I m pa ct ed B on e e nd s a r e d ri ve n i nt o e a ch ot h erB u r st F ou n d i n t h e s pin e d ue t o v er t ica l com pr es si onComminuted Force spli ts in several direct ions and forms a Tor Ysha peAv ul si on F r a ct u r e d u e t o t e ns ion a t l ig a m en t or t e nd on a t t a c h me nt

    S t ress D ue t o repet it ive force, usua lly per pen dicula r t o lon g a xisMay be confused wi th direct t ra uma t ransverse fracture

    S econ da r y t o pa t holog y S econ da r y t o loca liz ed or s ys tem ic d is ea s e t ha t h a s w ea ken ed t he

    bone

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    high velocity bullets a nd blunt force tra umato the cranium typically cause comminutedfractures.

    Crush fractures most commonly occur incancellous bone a nd r esult from th e applica-t i on of a di rect force t o t he b one, w hi c hcollapses on i tself . Three types of crushfractures are recognized: depression, com-

    pression, and pressure. The first refers tocrushing on one side of the bone (especia llycommon on t he ectocra nium) while th e sec-ond refers to a crushing force tha t originat eson both sides of the bone. The incompletepenet rat i on of a b one b y a l ow v el oci t yproject i le m ay resul t i n a crush frac t ure,such as depressed fractures caused by theimpact of musket bal ls (Liston and Baker,1996) or shotgun pellets (Swan and Swan,1989). Blunt trauma, such as that producedby a bludgeon, fi st , or ha mmer, or when a nobject is dropped on the hand or foot, resultsin crush fractures. The third type of crush-

    i ng i njury resul t s w hen developing b oneresponds to the application of direct force.Exam ples of t h i s l as t t ype are cult ural l yma nda ted bone altera tions, such as th e sha p-ing of immature cranial and foot bones byvar ious types of binding for bea utifi cation.

    Rarely, direct trauma injury that bruisesa joint may fra cture ar t icular cart i lage, and

    som et i m es t he sub c hondral b one as w el l ,causing separation of a fragment from themargin of the articular surface. This result-ing lesion may be confused with osteochon-dri t is dissecans, which is caused by a septicnecrosis an d is usua lly seen a s th e completeor incomplete sepa ra tion of a portion of jointcart i lage a nd subchondral bone, most com-

    monly on the femoral condyles. Osteochon-dritis dissecans is usually recognized in drybone a s a pit, often 2 to 5 mm in diam eter, inthe subchondral bone, al though new boneformation may part ial ly or completely fil lt he defect or m ay produce a deposi t t hatexc eeds t he l ev el of t he norm al ar t i c ul arsurface. The etiology of osteochondritis disse-ca n s i s u n ce rt a i n b ut i nd ir ect t r a u m a i sthought t o play a t least a contr ibutory role.

    I n d i r ec t t r a u m a . When a fractur e occursin a pla ce other th an the point of impact it issaid to result from indirect trauma (Miller

    and Miller, 1972). Oblique, spira l , green-st i ck, i m pac t ed, b urst , and av ul s ion frac -tures are consequences of indirect trauma(Fig. 2). An oblique fra cture, w here t he linean gles across the longitudinal a xis, is indica -tive of a combined a ngula ted/rota ted force(Ha rkess a nd Ra msey, 1991). If th e fractur eis well healed, this break is easily confused

    Fig. 1. Fractures caused by direct t rauma . From left to r ight : t ran sverse, penetrat ing, comminuted,and crush.

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    w i t h a s pi ra l l in e. A s pi ra l f r a ct u r e l in ewinds down a round a long bone shaft due toa rota t iona l and downwa rd loading stress onthe longitudinal axis. In some cases, such aforce a pplied to the tibia result s in a fra cture-dislocat ion of the ankle rat her tha n a spiralf rac t ure ( Harkess and Ram sey, 1991); a tother t imes, the force results in an associ-

    at ed proximal fi bular fracture.Torus or gr eenstick fractur es result frombending or buckling of bone when stress isappli ed. These of t en are due t o i ndi rectt r a u m a a n d a r e m os t com m on ly s ee n i nchildren, whose bones are st i l l pl iable andhence less likely t o break, inst ead producinga localized bulging on the bone. An exampleis a greenstick fracture of the clavicle thatresults during childbirth when the childsbiacromial breadt h is too lar ge to pass ea silythrough the mothers pelvic outlet . Green-stick fra ctures a re also chara cterized by a nincomplete fracture involving only the con-

    vex side of a bone tha t ha s been subjected t obending stress. In adults the ribs are com-monly a ffected.

    Less common fractures resulting from in-di rect t raum a are i m pac t ed, av ul si on, a ndburst fr a ctures. An impacted fra cture occursw hen t he b one ends a t a f rac t ure s i t e aredriven into ea ch other by the force of injury.

    Clinica lly, this is often seen in th e proximalh um er u s a s t h e r e su lt of a f a ll on t o a nout st ret ched hand, and i n t he m et acarpal sa s a r es ult of t r a um a t o t h e fi s t w h enpunching. An avulsion fracture is causedwhen a joint capsule, ligament, or tendon isstra ined an d pulls awa y from i ts at ta chmentto the bone, tear ing a piece of bone with it . A

    particular type of avulsion fracture leaves atransverse fracture l ine: a transverse frac-ture ma y occur to the ulnar olecra non pro-cess or the patel la i f the extensor musclescontract forcefully while the joint is flexed,and i n ext rem e c ases t he b one fragm ent swil l separ at e and ma y heal without unit ing.

    A burst fracture is located in the spine. Itresul t s f rom a v ert i cal com pression t hatruptures the intervertebral disc through thevertebra l end plate, forcing disc t issue intothe vertebral body (Fig. 3). A mild form ofthis injury is often seen in archaeologicalspecimens as a small , local ized, typical ly

    circular, depression in the end plate that isusua lly called a Schm orls node.Comminuted fra ctures may be due to indi-

    rect tra uma a s well as t o direct tra uma. Theindirect comminuted fracture is patternedlike a T or Y, and is produced by a forcetha t passes through th e bone, spli t t ing i t inseveral directions (P erkins, 1958). Crush

    Fig. 2. Fractures caused by indirect t rauma . From left to r ight : oblique, spiral , greenst ick due toan gular force, greenstick due to compression, impaction, a nd a vulsion.

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    f rac t ures a l so c an b e found as a resul t o fi ndi rec t t raum a, suc h as i n t he c al c aneusaft er a person ha s jumped from a height.

    S tr e ss f r a ct u r es. Repetitive force ca n re-sult in a str ess or fat igue fracture. The usualar eas of occurrence are the meta ta rsa l, calca -neus, a nd t ibia (Wilson and Ka tz , 1969).St ress fra ctures in the meta ta rsa ls ar e some-times referred to as marching fractures,since they are often diagnosed in mil i tarycadets. Those in the tibia have been knownfor some t ime to affect dancers, while thei ncreased i nt erest i n jogging and aerob ic

    d a n c i n g i n r e c e n t d e c a d e s a s w e l l a s t h eadoption of al ternative rel igious practiceshas led to their higher prevalence in othersegments of western society (Burrows, 1956;Cohen et al . , 1974). The fracture l ine isusual ly perpendicular to t he longitudinalaxis, therefore problems may arise in tryingt o di st i ngui sh b et w een s t ress and di rect

    t raum a t ransv erse i njuri es . C omm onl y astress fracture wil l be visible as a nondis-placed l ine or crack in the bone, cal led ahai r l ine f rac t ure, w hi ch i s not det ect ab l era diologically until a bony callus ha s formedover th e break.

    F r a c t u r es sec o n d a r y t o p a t h o l o g y. Frac-tures often occur secondari ly to a diseasealready present in the body. Systemic dis-eases such as m et ab ol ic di s t urb ances a ndnutri t ional deficiencies leave bone vulner-able to spontaneous fracture or to fracturefrom minor tr a uma . For exa mple, postmeno-pausal females ma y suffer fra ctures i f theirbones h a ve been wea kened by osteoporosis.Other skeletal markers of specific disease

    may aid in a t tributing cause to the fra cture:neoplast ic fra ctures are seen when the breakis through or a djacent t o a t umor th at is in,or of , b one, and t he c ol l apse of v ert eb ralbodies is not an uncommon consequence oftuberculosis in the spine (Potts disease).

    Fracture healing

    D u r a t i o n o f h ea l i n g . Fractures begin toheal immediately after the bone is broken,but the process di ffers for cancellous andtubular bone. Most investigators identi fyfi ve overlapping sta ges in tubular bone hea l-

    ing (Adams, 1987; Apley and Solomon, 1992;Paton, 1984). Table 3 summarizes the activi-t i es of t hese s t ages and t he approxi m at et i me a f t er i nju r y t h a t e a ch i s ob se rv ed .Heal ing norm al l y i s not v is ib le on radi o-graphs unt i l approxi m at el y 2 t o 3 w eeksaf t er t he i njury, w hen a cal l us of w ov enbone, the result of cell proliferation from theperiosteum, marrow cavity, and surround-ing connective t issue, appears around thesit e of i njury. The cal l us i nt ernal l y andext ernal l y b ri dges t he gap c aused b y t hefrac t ure and s t ab i li zes t he f rac t ured ends.Consolidation of this woven bone into ma-tur e lamellar bone occurs subsequently, butthe dur a tion of the process depends upon th enature of the fracture and the type of bonei nvol ved. I n a phal anx, a sol idl y uni t edfracture ma y develop in less tha n 1 month,while the same tra nsforma tion may t ake upto 6 month s in a tibia or femur. Bones of the

    Fig. 3. Burst fra ctures of the lumbar vertebrae in ayoung a dult ma le from the historic Fur Tra de period inAlberta.

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    upper limb tend to heal faster than do those

    of the lower l imbs, and spiral and obliquef r a ct u r es h ea l f a s t er t h a n d o t r a n s ve rs efractures.

    In contra st t o compact tubular bone, can-cellous bone ha s a meshlike structure withno medullary canal . This provides a muchlarger area of contact between fracture frag-m ent s , w hi c h fac i l i t a t es heal i ng. I n addi -t i on , t h is m es h ca n b e m o r e e a s il y p en -et rat ed b y b one-form i ng t i ssue t han cancompact bone, so the union occurs directlyb et w een b one fragm ent s i nst ead of i ndi-rectly via the periosteal and endosteal cal-lus. The initial haematoma is penetrated by

    proliferat ing bone cel ls which grow fromopposing fracture surfaces. The developingt i ss u es f us e w h en t h ey m ee t a n d s u bs e-quent ly calcify t o form w oven bone. Healingis thus simpler an d fa ster in can cellous bonetha n in compact bone.

    Because there is a delay before healing isvisible m acroscopica lly or ra diographically,it may be difficult to distinguish some post-mortem breaks from unhealed premortemfractures. Perimortem fra ctures is th e termg iv en t o s u ch i nju r ie s, w h i ch m a y h a v eoccurred in the recent antemortem period( i . e . , up t o 3 w eeks b efore deat h) and are

    t herefore unheal ed, or t hat a l t ernat i v el ymay have occurred in a postmortem periodt hat i s o f i ndet erm i nat e l engt h (perhapsweeks or month s) but dur ing wh ich th e boneis still relatively fresh and its organic compo-nents not yet deteriorat ed. Otherwise, distin-guishing between a ntemortem/perimort emt r a u m a a n d t h a t w h i ch cl ea r l y occu r r ed

    after death is predicated upon the di fferent

    fra cture properties associat ed with bone tha tretains i ts viscoelast ic nat ure and bone tha tdoes not , and upon t he di fferent appear-ances of bone surfaces after various postmor-tem interva ls (B uikstra a nd U bela ker, 1994;Maples, 1986; Mann and Murphy, 1990;Ubelaker and Adams, 1995). Antemortem orperimortem fra ctures can be identified by 1)any evidence of healing or inflammation; 2)the un iform presence of sta ins from w at er,soi l , or vegetat ion on broken and adjacentbone su rfa ces; 3) the presence of gr eenstickfractures, incomplete fractures, spiral frac-tures, a nd depressed or compressed fra c-

    tures; 4) oblique angles on fracture edges;an d/or 5) a pat tern of concentric circula r,radi at i ng, or s t el l a t e f rac t ure l i nes . P ost -m ort em frac t ures , i n c ont rast , t end t o b ec harac t eri z ed b y 1) sm al l er f ragm ent s ; 2)nonuniform colorat ion of the fracture endsand t he adjac ent b one surface, espec ial l yl ight -c ol ored edges ; 3) squa red frac t ureedges; and 4) absence of fracture patterningdue to th e increased tendency of dry, brittle,bone to shat ter on impa ct.

    C o m p l i c a t i o n s o f h e a l i n g . Complica-t ions should be assessed when examining

    fra ctures because they ma y provide informa -tion regarding mobility, morbidity, mortal-it y, a n d m ed ica l t r ea t m e nt or t h e l a ckt hereof . I n addi t i on t o t he f rac t ure t ypesdescribed a bove, the relat ionship of the fra c-ture to surrounding t issue is referred to asclosed or open. When the fractured bonedoes not come into contact with the outer

    T ABL E 3 . T h e p r o ces s a n d d u r a t i o n of f r a c t u r e h ea l i n g i n t u b u l a r b on es

    (Adams, 1987, Apley and Solomon, 1993, and Paton, 1984)

    H ea lin g st a ge H ea lin g processes D ur a t ion

    H a e m a t o m a f or m a t i on B l oo d f r om t o rn v es s el s s e ep s ou t a n d f or m s a h a em a t o m a 2 4 h o ur sFra ctured bone ends die due t o lack of blood supply

    Cel lular prol i ferat ion Osteoid is deposited around each fragment by osteoblasts ofperiosteum a nd endosteum and pushes ha ematoma a side

    3 weeks

    Fra cture is bridged; visible in dry boneCal lus formation Cal lus of woven bone forms from mineral izat ion of osteoid and

    acts as a splint for periosteal and endosteal surfaces3 to 9 weeks

    Visible radiologicallyC o n so li d a t i on M a t u r e l a m e ll a r b on e f or m s f r om ca l l u s p r ecu r s or a n d r e s ul t s

    in a solidly united fracture areaVar ies by skeleta l ele-

    ment from a few weeksto a few months

    R e mo de ll in g G r a d u a l r e m od e ll in g o f b on e t o i t s o ri g in a l f or m , s t r e n gt h -ening along lines of mecha nical stress

    6 to 9 years

    Increased density on radiographs marks the fracture site onadult bones

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    surface of the skin, the fracture is termedclosed. An open fracture, also known as acompound fracture, is when the bone pro-trud es through th e skin or th e skin is broken

    to the level of th e bone, as in a crushing orpenetra ting w ound. Open fractures ar e proneto infection, which hinders the union of thefracture and creates instability. A pathogen,Staphylococcus aureusin a bout 90%of clini-cal cases (Ortner an d P utschar, 1981), ma ybe introduced to t he body thr ough an openfra cture from surface conta mina tion or froma penet rat i ng i nst rum ent or c ont am i nant .Although th ere is a tendency to rega rd local-ized infections as related to observed frac-tures, but to interpret nonlocal ized infec-tions a s unrelated to fracture, posttrauma ticinfection ma y in fa ct be present ei ther a s alocalized condition or, due to h emat ogenousdisseminat ion of the pat hogen, a s a syst emicinfection. Whether localized or systemic, ifthe bodys immune sy stem is u na ble to com-bat the infection successfully bony responseis usua l ly visible in the form of periosti t is(an infla mma tion of the periosteum) or osteo-myelitis (a more severe bone infection thatinvolves the medullar y cavity ). P eriostitis isusua lly cha ra cterized by foca l periosteal boned ep os it i on t h a t m a y e ve nt u a l ly f or m aplaq uelike sheet over th e cortex. Osteomyeli-tis is identifi ed by a t hickened contour in th e

    area of t he f ra ct ure and t he b one m ay feelhea vier. P a th ognomonic evidence of osteomy-elitis results from the development of sub-periostea l abscesses tha t deprive the bone ofi ts blood supply and lead to necrosis (thedead bone forms a sequestr um). The perios-teum continues to produce new, hypervascu-lar bone a round the sequestrum, forming ashell of bone called involucrum . The su bperi-osteal pus must escape t hrough the involu-crum to the skin surface, however, and indoing so forms one or more sinu ses (cloaca e)in the involucrum for pus drainage. In drybone the sequestrum, lying under the involu-

    crum, ma y be visible thr ough a cloacal open-ing. Postt ra uma tic osteomyelitis is most com-m onl y ob served i n t he crani um and l ongbones of archaeological skeletons.

    Fra ctures inevita bly result in the ruptureof minor blood vessels but this is not usuallya serious complica tion. In some ca ses, how-ever, bone displacement can compress or

    t w i st b lood v essel s a nd l ead t o i schem ia.This will delay the healing process and couldlead to bone death if unrelieved. Avascularnecrosis n orma lly occurs near the ar t icular

    ends of b ones w here t he b l ood suppl y t osubchondral bone is l imited. Death of thet i ss u e b eg in s a w e ek a f t er t h e n u t r ie ntsupply is reduced and may continue for up to4 years. D uring this t ime the bone loses i tstrabecular structure, becomes granular, andbegins to disintegra te due to muscle stressor body w eight. The adja cent a rticular ca rti-lage a lso dies as a r esult of deficient nourish-ment, usually resulting in osteoarthritis.

    N erv e i njuri es a l so m ay b e associ at edwith fra ctures. Three ty pes of nerve injuriesare general ly recognized. Damage is sl ighti n neurapraxia and resul t s i n t em poraryimpairment that corrects itself within a fewweeks. In contra st , the interna l nerve archi-t ect ure i s preserv ed b ut axons are b adl ydamaged in axonotmesis, resulting in periph-er a l d eg en er a t ion t h a t m a y t a k e m a n ym ont hs t o heal . Suc h a l es ion m ay resul tfrom pinching, crushing, or prolonged pres-sure. The most serious type of n erve injury,neurotmesis, involves complete division of anerve, e it her t hrough sev eri ng or sev erescarring, and requires surgical repair. Theconseq uences of these ty pes of nerv e injuriesrange from loss of sensation to loss of func-

    t i on. Usual l y t he l oss i s t em porary , b utmuscle atrophy may result a nd i f the nerveloss is prolonged or permanent the boneswill display signs of disuse atrophy as well.This sequel would be most likely in archaeo-logical cases of neurotmesis. In addition, ifthere is loss of innervation to the fracturesi t e , t he i ndi v i dual w i l l not feel pai n andmay therefore continue to use the brokenb one, i m pai r ing heal ing. Frac t ure of t hev ert ebral col um n m ay resul t i n dam a ge t othe spinal cord or spina l nerves, wit h para ly-sis below the level of the injury a possibleoutcome. Depressed skull fractures w ith en-

    docranial displacement are usual ly associ-at ed w i t h s ignifi cant b rai n i njury, w hi chmust also be considered in cases of l inearfractures of the cra nial vault .

    Another complica tion is posttra uma tic os-sifi cat i on of a haem at om a, w hi ch resul t swhen absorption of the haematoma is pre-v ent ed b y excessi ve s t ress plac ed on t he

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    periosteum. Asmooth mass of bone is macro-scopica lly visible aft er 2 months, w ith ca lci-fi cation being visible ra diological ly a feww eeks a f t er t he i njury. Al t hough usual ly

    benign, movement ma y be restricted if thereis joint in volvement.

    If joint function is affected by traumaticinjury, osteoarthritis may develop as a com-plicat ion. S t i ffness caused by fi brous a dhe-sions or joint swelling may lead to prolongeddisuse of the joint or l imb. Shortening orangulat ion may result in some loss of nor-mal function in the affected l imb or in thejoints directly a bove and below the fra cture;this may be di fficult to interpret since un-u s ua l b iom ech a n i ca l s t r es s a t a joi nt i nw hi ch a f rac t ured b one part i ci pat es m aycause osteoarthri t is, but i t is also possiblefor a jo i nt on an uni njured l i m b t o b e a f-fected. The la tt er might occur, for exa mple,i f w ei ght b eari ng w as shi f t ed i n order t ofavor the injured leg. Premat ure deteriora-t i on of ar t i c ul ar c art i l age and sub sequentdeterioration of subchondral bone are com-mon complicat ions of breaks affecting thejoint sur face itself, since cart ilage repair is avery slow process. Such fractures also canresult in a nkylosis of th e joint.

    Three final complications of fractures aredelayed union, nonunion, a nd malunion. Incl inical sett ings the union of a fracture is

    defined as delayed i f i t has not occurred inthe time expected for that skeletal element,age, and sex of t he i ndi v i dual , and i t m ayeventua l ly be classed as a nonunion. In drybone specimens, of cours e, delay ed but even-t ual l y successful union cannot b e di st i n-guished from undelayed union. Several fac-tors may impede the process of healing, butovera ll poor healt h a nd/or nut rition in a n-cient populations may be a largely unrecog-n i ze d con t r i b ut o r (G r a u e r a n d R ob er t s ,1996).

    The dia gnosis of nonun ion is a pplied wh enthe fracture fragments fai l to unite and the

    mar row cavity seals. Ra diological ly, non-union may be identified by sclerosis at thebone ends. After a prolonged period of time,t he f ragm ent s t ake on a rounded appear-ance at their ends, which are connected byfi brous t issue. Nonunion may result frominadequate bone heal ing due to infection,inadequate blood supply, insufficiency of vi-

    tamin D or C or of calcium, excessive move-ment between bone fra gments during hea l-i ng, sof t t i ssue b ei ng c aught b et w een t hefragment ends, ina dequate contact between

    the fragments, presence of foreign material,or from the dest ruction of bone due to pat hol-ogy or the injury itself (Altner et al . , 1975;Ka rlstrom a nd Olerud, 1974; Sevit t , 1981;Stewart, 1974; Urist et al . , 1954; Yamigashian d Yoshimura , 1955). If there is persistentm ov em ent b et w een t he ununit ed ends, apseudart hrosis , or fa l se joi nt , m ay form ,although this complication is relatively rare(Stewa rt , 1974). S tudies of modern huma npopulations indicate a frequency of pseuda r-throsis of less than 5%(Heppenstall , 1980;Urist et al . , 1954), while an examination ofdat a from tempora l ly, geographical ly, an dcultural diverse archaeological populationsreveals an average frequency of 2%(Burrellet al . , 1986; J imenez, 1994; Lovejoy et al . ,1981; Stewart, 1974). Among alloprimates,da ta from B ra mblett (1967), J urm a in (1989),Lovell (1990), a nd Schu ltz (1937, 1939) a lsogive an average pseudarthrosis frequency ofa pproxima tely 2%.

    A m al uni on consis t s of a f rac t ure t hatheals leaving a deformity. This may occurw hen a f rac t ure has not b een reduc ed orwhen reduction was not maintained, leavingthe fragments to heal grossly angulated or

    excessively shortened. S hortening is causedby overlap, substantial angulat ion, crush-ing, or gross bone loss. Injuries to growingb one t ha t a f fect t he epiphyses a nd l ead t oprem at ure fusion of t he grow t h plat e m ayresult in shortening, as may bone infarctionresult ing from sickle cell disease, whichmost often affects the epiphyses of the grow-ing skeleton, especially those of the proxi-ma l femur. The presence of a sh ortened bonei s m ost det r i m ent al t o t he l ow er, w ei ght -bearing limbs, a lthough a difference of up to20 mm is consider ed by clinica l pra ctitionersto be tolerable. A greater loss in length can

    l ead t o b ac kac he from pel vi s t i lt i ng andlateral and rotat ional spinal deviat ion. Re-cent st udies have interpret ed minimal defor-mity in bones tha t ar e l ikely to be severelyaffected when fractured as evidence for im-mobilization of the injured par t a nd possiblem ed ica l t r ea t m e n t (G r a u er a n d R ob er t s ,1996).

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    DESCRIPTIVE PROTOCOLS FORFRACTURES

    Proper description of an injury is the first

    step in tra uma an a lysis (Ortner and Putschar,1981; Steinbock, 1976) and is the basis fordetermining the mechanism, or proximatecause, of the injury. In t urn, a n understa nd-ing of the proximate cause is crucial for thei de nt i fi ca t i on of t h e u lt i ma t e ca u s e oftrauma, usual ly behavior. Proper descrip-tion of observed lesions a lso provides othersc hol ars w i t h an opport uni t y t o agree ordisagree w ith the diagnosis and /or infer-ences tha t a re ma de about the sociocultura lor environmental context of the injury. Al-though severa l models proposed recentlyhav e m ade great s t r i des i n s t andardi z i ng

    descri pt i v e prot ocols (e .g . , Bui kst ra andU belaker, 1994; Da stug ue and G erva is, 1992;Grauer and Roberts, 1996; Roberts, 1991),pal eopat hologi st s hav e not yet reached acon s e n s us o n d e s cr i pt i v e s t a n d a r d s f ort r a u m a a n d m a n y a r e n o t a l w a y s f a m i l i a rwith the underlying mecha nisms of injury.Ideal ly, a ny method of fra cture descriptionwill recognize two main sources of confusionin interpretat ion: the variat ion in appear-ance expressed by fractures caused by thesam e m ec hani sm of i njury , as w el l as t hesimilarities in a ppea ra nce displayed by frac-t ures caused b y di fferent m echani sm s ofinjury. Ultimately, proper fracture descrip-tion should seek to improve the accuracyand reliability of interpretation without ex-ceeding t he l imits of inference tha t ar e setby the descriptive dat a t hemselves.

    Al t hough frac t ure t ypes a re here sub -sumed under their proximate cause, whendescribing a nd interpreting injury th e fra c-ture type is usua lly recognized first . Identifi -cation of the mechanism of injury then fol-lows logical ly, a nd t he third step in tra umaana lysis involves interpreta t ion of the ul t i-mate cause of the injury. For example, an

    impacted fracture of the distal radius withpost erior di splac em ent of t he di st a l f rag-ment ma y be recognized as a Collesfra cturedue to i ts chara cterist ic locat ion an d defor-mity. The proxima te cau se of the injury m a ythen be identified a s indirect tra uma. Int er-preting the ul t ima te cause may be di fficult ,but a fal l onto the outstretched ha nd w ould

    be a logical conclusion. I f the fracture w asobserved in an older female, the possibilityof the fra cture occurring seconda ry t o osteo-porosis could a lso be considered.

    The principal aim of most protocols hasbeen to establish standardized descriptionsfor fractur es observed in dry bone, a lthoughad ditional objectives, such a s the evalua tionof evidence for treatment of traumatic inju-ries are sometimes a lso stated (e.g. , Gra ueran d Roberts , 1996; Roberts, 1991). Threerecently developed protocols are outlinedhere.

    The repatriation of Native American pre-historic and historic skeletal remains drovethe development of sta nda rds for da ta collec-tion tha t includes procedures for document-ing fra ctures (B uikstra a nd U belaker, 1994).These procedures recognize n ine t ypes offra ctures and eight varieties of shape cha ra c-t eris t i cs . A ll t ypes and v ari et i es are notmutually exclusive, but may have restrictedapplicat ion. Sha pe chara cterist ics, for ex-ample, describe lesions caused by blunt orsharp forc e and b y projec t i l es , as w el l asradi at i ng f ra ct ures and am put at i ons . P eri-m ort em frac t ures are i dent i fied a t a t h i rdlevel of description, fol lowed by sequelaesuch as healing sta tus a nd var ious complica -t ions. Dislocations are classed separately.The recommended data collection forms and

    descriptive protocol do not provide for ma l-union as a component of fracture descriptionspecifi cal ly, but ra ther under t he pa thologycategory of a bnormality of shape, in w hichma lunion w ould be identifi ed as either ba relydiscernable or clear ly discerna ble a ngula tion.

    Asecond method wa s designed specifica llyt o desc ri b e f rac t ures i n a w ay t hat w oul dprovide the information necessary to exam-ine the t echnology and knowledge of tr eat-ments in past societies (G ra uer an d Roberts,1996; Robert s, 1991). The meth od d escribesthe location an d type of fractur e and empha -sizes evaluation of the success of long bone

    h e a l in g . M a c r os cop ic a n d r a d i o g r a p h icmean s a re employed to a ssess complica tionsof shortening and deformity, and sequelaesuch as infection and osteoarthri t is. Skullf rac t ures are desc ri b ed as resul t i ng f romb l unt or sharp forc e and are ev al uat ed i nt erm s of heal i ng as w el l as ev i denc e fort r e pa n a t i on . Th e n e ed f or r a d i o gr a p h i c

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    evalua tion of fra ctures in order t o determinethe a mount of heal ing a nd th e part icular s ofdeformity a nd/or displacement is str essed,

    a s i s t h e i mp or t a n ce of r a d i og r a ph y f ordetecting and interpreting well-remodelledfractures (Grauer and Roberts, 1996; Rob-ert s , 1991). Un fort una t el y, ra di ogra phi cequipm ent i s not a l w a ys av ai l ab le , espe-ci al ly i n fi eld set t i ngs , and t he i nt erpret a-tion of ra diographs ma y be mad e difficult bypostmortem a ltera tions common in ar chaeo-logica l contexts, such a s soil inclusions t ha taffect densi ty or the di fferential identifica-tion of osteoporosis versus diagenetic boneloss (Roberts, 1991).

    Final ly, a third system concerns cranialvault injuries, categorizing them as pierc-

    ings, depressions, gashes, cuts, and sl ices(Filer, 1992). The first category is describedas consistent with a penetra t ing injury, thesecond with blunt force trauma, and the lastthr ee a s r esulting from edged/bladed imple-ments, including sha rp projectiles. The ma -jori ty of these lesions were interpreted asresult ing from interpersonal violence, anassessment not inconsistent with the appar-ent culture-historical context of the remains.

    It is l ikely t hat no one system of fracturedescription will suit all investigators, sincesome will be more or less concerned w ith t heaffected body part, specific complications, or

    possible causat ive behaviors. Most proto-cols, however, sha re similar basic cat egoriesof description. The method for fracture de-scription tha t is presented below incorpo-rates these categories in a system adaptedfrom clinical an d forensic medicine. I t ispredicated on identification of the skeletalelement(s)involved and the type of injury, as

    well as detailed descriptions of deformationand of any a ssociat ed nontrauma tic lesionst hat m ay i ndicat e causal i t y or post i njury

    complicat ions. The informa tion thus ob-ta ined t hen serves a s a basis for inferencesabout t he mechanism of injury, which can inturn provide clues as to the social, cultural,or environmental associations of the injury.The method outlines descriptive features forcranial a nd long bone fractures since thesepredomina te in th e paleopat hological litera-ture.

    Description of cranial fractures

    The interpretat ion of the mechanism ofinjury of cra nia l fractures relies on a va rietyof char acterist ics of the fra cture, such as t he

    bones involved, pat terning of fracture lines,a n d p r es en ce of d e for m a t i on (G u r d j ia n ,1975; G ustilo, 1991; H ooper, 1969; for acomprehensive discussion of lesions of thecalvar ium, see Ka ufma n et a l. , 1997). Str essfractures an d fra ctures seconda ry t o pat hol-ogy are uncommon in the cranium. The mostcommon fractures of the cranium affect thev a ult a n d a r e ca u s ed b y d ir ect t r a u ma .These can be described according to theirbasic type, usually linear, crush, or penetra t-ing (Fig. 4), wh ich a re not necessarily mu tu-ally exclusive. Although vault fractures arem ost com m on, t he b ase, m a xil lae , nasa l

    bones, orbits, a nd/or zygoma e ma y be fr ac-tured al ternatively or addit ional ly, and thetemporomandibular joint may be tra umat i-cally disloca ted.

    Low v el oci t y, b l unt t raum a t o t he headm ay resul t i n s im ple l inear f rac t ures ordepressed (crush) fra ctures. The kineticsinvolved ma y rela te to a ccelera tion injuries,

    Fig. 4. Common fractures of the cranial vaul t . From left to r ight : simple linear fracture due to blunttrauma, comminuted depressed fracture due to blunt trauma, and comminuted penetrating fracture froma high velocity projectile.

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    in which the hea d is struck by an object an dset in motion, or decelerat ion injuries, inwh ich th e moving hea d suddenly comes to ahalt. In either case, the curve of the skull at

    the point of impact tends t o fla t ten out , a ndas a result the force of the impact is distrib-uted over a relat ively la rge a rea. The bonesurrounding the area of impact bends out-wa rd, an d, if the deformity of the cran ium isgreat enough, fracture l ines begin, usual lyin the areas subjected to bending outward.The areas of b endi ng a re not uni form l ycircular, since the degree and direction tow hi ch t he f rac t ure l i nes ext end dependsupon both the magnitude of the applied forcean d the local bony a rchitecture.

    P enet rat i ng i njuri es of t he c rani um arecharacterized by a small area of impact witha localized area of distortion and a re usuallycaused by sharp-edged objects or projectiles.With higher velocity impact, the inbendingof the skull remains localized but the depthof penetration increased. As a general rule,w h en t h e a r e a of im pa c t d ecr ea s es t h estresses are more local ized but greater inmagnitude and the stresses in surroundingareas diminish. The severi ty of impact indirect cran ial tra uma is usual ly determinedfrom t he ext ent and separat i on of l i nearfra ctures, by th e extent of comminution of alocalized fractur e, or by the displa cement ofbone fragments in penetra t ing w ounds.

    I ndi rect t raum a i njuri es are rela t i v el yrare, but may result from vertical loadingforces transmitted from the feet or buttockswhen a person falls from a height. A basilarringfr actur e around the fora men magn umis an example of such an injury; i t reflectsi m pac t forc es t ransm i t t ed up t hrough t hecervical spine an d occipita l condyles. B as ilarfrac t ures t hrough t he pet rous b ones a ndfractures of the mandibular condyles havebeen observed to result from impact to t hechin (Ha rvey a nd J ones, 1980).

    Description of long bone fractures

    In contra st to fractures of fla t a nd irregu-l ar b ones, f rac t ures of appendi cul ar l ongbones (and, by extension, short bones) oftenrequi re m ore c om prehensi ve descri pt ionsince t heir posit i ons i n t he skel et on andtheir functions ma ke them more susceptibleto a variety of forces. Long bone fractures

    from arc haeologi cal cont ext s can b e de-scribed in a ma nner ada pted from tha t usedin clinical orthopedics (e.g., Gustilo, 1991;Harkess and Ramsey, 1991; Schultz, 1990)

    and c an b e firs t c l ass i fied as i nt raart i c ul ar(involving a joint, including the metaphys-eal region) or extraart icular. Intraart icularfra ctures a re described as either linea r, com-minuted, or impacted. Extraart icular frac-tures ar e described a s l inear, comminuted,or segmental.

    Linear fractures fal l into thr ee subtypes,tra nsverse, oblique, and spira l , al l of w hichhave been previously described. Commi-nuted fractures are categorized according toth e size of the fr a gment s (multiple or butt er-fly ) and the percentage of th e sha ft (50%or 50%) tha t is involved. A butt erfl y fra c-ture is formed from a combination of com-pression a nd t ension stresses th at result int he separat i on of a t r i angul ar f ragm ent ofbone. Segmental fra ctures a re identified bythe multiple fracture l ines that divide theb on e i nt o a t l ea s t t w o s eg m en t s a l on g alongitudinal axis. The location of the frac-t ure should b e not ed as occurri ng a t t heproximal end, dista l end, or sha ft (either th eproximal, middle, or dista l third of the sha ftor one of the junctions t hereof).

    The final components of long bone frac-tur e description a re length , apposition (shift),

    rota tion, a nd an gulat ion (a lignment), identi-fied b y t he ac ronym , LARA. C onv ent i ondecrees tha t w hen describing the four compo-nent s t he di s t a l f ragm ent i s m easured i nrelat ion to th e proximal fra gment. The prin-cipal a ims here a re to describe fra ctures sot hat t he m ec hani sm of i njury c an b e de-duced, and to dist inguish fractures with noor slight deformity from those with markeddeformity.

    Length o f t he b one i s m easured w i t h anosteometric board and the maximum lengthis recorded (per Bass, 1987). Length is re-corded a s n orma l , distracted, or shortened,

    an d is determined by compar ing the injuredbone to its counterpart, if possible. Distrac-t i on i s a l en g t h en in g of t h e b on e a n d i scaused by the separation of bone fragments,often due to muscular forces. Bones them-sel ves m a y di st rac t a f rac t ure, how ev er,such as when an intact ulna pulls apart thefragment ends of a fra ctured radius or wh en

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    a fra ctured t ibia is associated with a n inta ctfi bula. Distraction a lso may be caused w hentissue is caught betw een fra gment ends. Incontra st , shortening results w hen muscular

    forces pull the fragments over each other.This typical ly occurs when broken bonesha ve not been set, often d ue to severe pain orm uscl e spasm , or i f a f rac t ure reduct i onfailed because of inst ability.

    Apposition is the percentage of bony con-ta ct betw een fragment ends in fresh injuriesan d is mea sured on ra diographs. Appositionfrom an x-ray is measured using a ruler andis expressed as a percentage, the horizontaldisplacement being a function of the sur facea rea of bone. Ther efore, if th ere is no horizon-ta l displacement betw een the fra ctured boneends when hea led, tha t is, the bone ends arein perfect alignment, the bone is 100% ap-posed. In dry bone, however, shifting of thedistal fragment in relat ion to the proximalend can be recorded in the a bsence of radio-graphs. I f t he bone is viewed in a nat omicalposi t i on, a m edi al or l a t eral shi f t m ay b eseen; if viewed in a lat era l position, ant erioror posterior displacement may be observed.The shift in both the an teroposterior (AP)and l a t eral p l anes shoul d b e not ed, as t hebone can be displaced in both directions.

    Rotationoccurs when the dista l fragmenthas t urned rel a t i v e t o t he proxi m al f rag-

    m ent . There i s no m easurement , b ut t hedista l portion is recorded a s being interna llyor externally rotated. This is usually easilyi dent i fia b le i n dry b one, especi al ly i f t heaffected bone can be compar ed to the contr a -latera l element. I f rotat ion is observed, theadjacent joint surfaces should be examinedsince rotat ion may result in osteoarthri t is,or in ankylosis of a joint i f l igaments weretorn in the injury.

    A n g u l a ti o n a t t h e f r a c t u r e s i t e i s m e a -sured in degrees with a goniometer. Thismeasurement is easily obtained from a ra dio-graph b ut a l so m ay b e ob t ai ned from t he

    bone. One end of the goniometer is pla ced onthe midline of the proximal fragments longi-tudina l axis, the other end on the a xis of thedistal fra gment with the center of the goni-ometer directly over the fracture si te. Thenumber of degrees the distal fragment hasdisplaced in relat ion to the midline of theproxim al f ragm ent i s t he angul at i on. The

    direction of movement must also be noted.I n t he AP v iew, t he di s t a l port i on of t hedistal fragment wil l move medial ly (varus)or l a t eral ly (v al gus). I n t he l a t eral v iew,

    ant erior a ngulat ion refers t o the distal por-t i on of t he di st a l f ragm ent m ov ing ant eri -orly so tha t the fra cture site a ppea rs posteri-orly bowed. Posterior angulat ion refers tot h e d is t a l p or t ion of t h e d is t a l f r a g me ntmoving posteriorly; the fra cture site appearsanteriorly bowed. Degree and direction ofangulat ion should be measured in the APa n d l a t er a l p os it i on s a s b ot h p la n e s a r eoften affected.

    Examples of long bone fractures

    The value and a pplica tion of sta nda rdizedfra cture descriptions is illustr a ted here witht he descri pt i on of radi ographs f rom fourcl inical cases at the Universi ty of AlbertaHospital in Edmonton. With known mecha-nisms of injury, treatment, and fol low-up,t hese c ases unam b iguously i ll ust rat e t heskeletal effects of trauma and their variabil-i t y of expression. For each set of radi o-graphs, fra ctures were noted for t heir type,the bone(s) involved, a rea of involvement,degree of heal ing, length, apposit ion, rota-t i on, and angul at i on. A pposit i on dat a arereported t o 5%. The mea sur ement of an gu-lation was found to be the most problematicand consequent ly a l l angulat i on dat a arepresented t o 2 .3 The sex a nd age of eachpatient were recorded al though other per-sonal , identi fying information was not re-vealed. Although the degree of deformity iss om et i m es u s ed t o a s s es s t h e e xi st e n ceand/or qua l i ty of medical treat ment in th epast, these examples reinforce the observa-tion that the association is not always direct(Gr auer an d Roberts, 1996). F ra cture inju-ries often improve with t ime but converselyt h ey m a y d et e r ior a t e a n d i nd iv id u a l r e-sponses to fra cture var y w idely.

    A di rec t t raum a t ransv erse f rac t ure re-sulted when a 20-year-old male was kickedin the shin while playing soccer. Figure 5a isa l a t eral v i ew radi ograph t aken i m m edi -

    3In order to evaluate interobserver error all clinical cases wereindependently scored by N. Lovell and C. Prins. The error inmeasured length as 1 mm; in apposition 5%; and in a ngula -tion 2; al l adequate for dist inguishing between none, s l ight,and marked deformity.

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    at el y post i njury t hat show s a t ransv erse,

    m i dshaf t t i bi a l f rac t ure w i t h no fi b ular i n-volvement. The bone was perfectly alignedon b ot h t he i ni t ia l x-rays and t hose t a kenm ore t han 5 m ont hs l a t er ( Fi g . 5b ) . Thedegree of c al l us form at i on m ay appear t othose who are inexperienced with cl inicalcases to be excessive, given the apparentlack of angular deformity, displacement, orcomminution, but t his example is fairly ty pi-cal of such injury. Not al l transverse frac-tures h eal a s nicely, however, an d nonunion,despite good alignment, may often occur inthe t ibia a nd/or fi bula du e to their inherenti n s t a b i li t y w h e n s u p por t i n g t h e b od y s

    weigh t in locomotion.In some cases fra ctured bones hea l well inone di m ensi on, onl y t o det eri orat e i n an-other. In i t ial ra diographs of a 24-year-oldmale injured in a motor vehicle a ccidentshowed a transverse fracture at the junctionof the mid and distal t hirds of the left t ibia,w i t h t w o fib ul ar f rac t ures , one a t t he sam e

    lev el a s in t h e t i bia a n d a n ot h er a t t h e

    proxi m al end of t he shaf t . Bot h t i b i a andfi bula were in perfect alignm ent wh en viewedant eroposteriorly immediately a fter t he in-jury, although 3 of posterior angulation oft h e t i b ia w a s n ot e d i n t h e l a t e r a l v i ew .Figures 6a and 6b were taken more than 4m o n t h s a f t e r t h e i n j u r y a n d t h e f r a c t u r el ines are st i l l visible. In the AP view, thetibia has now shifted lateral ly by about thew i dt h of t he b one cort ex, a nd show s 4 ofvalgus an gulat ion. The midsha ft fi bular fra c-t ure a l so di spl ays 4 of v a l gus i n t he APplane. The la tera l view, however, now showsthe t ibia in good al ignment. Although the

    effects of high velocity vehicular accidentsm ay appear t o hav e l i t t l e rel ev anc e t o ar-chaeological remains, multiple fractures ofthis t ype ha ve been noted in h istoric cases ofi nju r y i n h or s e-d r a w n ca r t a n d ca r r i a g eac c i dent s , and t hi s c ase has ob v i ous rel -evance for modern forensic investiga tions ofdry bone lesions.

    F i g . 5 . Tr a n s v er s e f r a c t u re d u e t o d i r ec t t r a u m a . a: Radiograph taken immediately post injury,showing a t ran sverse midshaft fracture wi thout fi bular involvement . b: Radiograph taken more than 5months later, showing callus around the fracture site.

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    Figure 7a is an immediate postinjury x-ray of a 54-year-old ma le who fel l and suf-fered oblique, midsha ft fra ctures of the rightt ibia and fi bula. I n th e AP view there is 11of valgus angulat ion in the t ibia and 13 of

    valgus angulat ion in the fibula. The lateralview shows 10 mm of shortening in both t hetibia and fibula and 1 of posterior angula-t i on i n t he t i b i a . Bot h b ones hav e shi f t edanteriorly about the width of the bone cor-tex. Figures 7b and 7c were taken 6 monthslater. The fracture l ines are st i l l very evi-dent , l i t t le cal lus is seen, and the fra gmentends are rounded, suggesting nonunion inb ot h b ones. Short eni ng has l essened t o 6mm in both t he t ibia an d fi bula. On t he APview the t ibia reta ins 11 of valgus a ngula-t ion but the fibula now displays only 4 ofvalgus. In t he latera l view, posterior angu la-

    t i on i n t he t i b i a has i nc reased t o 4 , 1 o fpost eri or angul at i on i s seen i n t he fib ul a ,an d both bones reta in their ant erior shifting.

    A good example of a rotat ion injury w ithno fibula r involvement is a spira l fracture ofthe dista l third of the right tibia in a 12-year-old male who fel l off his bicycle (Fig. 8).Ca llus is evident since the radiogra phs were

    ta ken about 2 month s postinjury, a nd on theAP view there is 5 of valgus angulation. Thetibia is not shortened, probably because thei nt a c t fi b ul a h el pe d i t m a i n t a i n n o r ma ll engt h. On t he l a t eral v i ew , t here i s 6 o f

    ant erior a ngulat ion in the t ibia.ANATOMICAL SUMMARY OF

    FRACTURES AND DISLOCATIONSCOMMONLY SEEN IN

    ARCHAEOLOGICAL BONE

    To aid the diagnosis of t ra uma accordingto the mechanism of injury, this section isorgani z ed as an a t l as and desc ri b es t hosefra ctures a nd disloca tions commonly seen inarcha eological bone according to t heir a na-tomica l loca tion. The possible complicat ionsof the injury a nd th eir affects on healing a lsoar e described.

    Cranium

    Fra ctures of the bones of the cranium va ryconsiderably, but perha ps t he most com-monly described are those involving the flatbones of the vau lt. Typica lly, th e pat terningof fra cture lines on th e cranium is correlatedw i t h t he sev eri t y of t he forc e: w het her a

    Fig. 6. Single t ibial fracture wi th double fibular fra cture. These radiographs w ere taken more tha n 4months postinjury an d the fra cture lines are still visible.a:Anterior view. b:Latera l view.

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    blow lands on the frontal, occipital, or pari-et a l region, a s i ngl e l inear f rac t ure l ineindicates less force than does a pattern ofconcent r ic and radi at i ng s t ell a t e f rac t urelines (Gurdjian et al., 1950). The position offrac t ure l ines c an som et im es b e used t oi dent i fy t he poi nt of i m pac t . St el la t e , or

    sta r-sha ped, fra cture lines form at the pointof impact , for example, and radiat ing frac-ture lines run laterally, away from the pointof impact . C oncentric heaving fra ctures ar ecaused by shearing forces a nd ha ve cha rac-teristics, such as bevel an gle, tha t can dist in-g u is h b et w e e n h i g h v el oci t y a n d b lu n t

    Fig. 7. Oblique, midsha ft fra ctures of the right tibiaa n d fi b u l a . a:Immedia tely postinjury. Anterior view (b)and lateral view (c) 6 months postinjury. Nonunion isevident in both bones.

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    tra uma injury (Berryman and Ha un, 1996).With blunt trauma the concentric fracturesare c aused b y forc e f rom out si de t he c ra-

    nium, which leads to beveling on the innertable, whereas with high velocity projectiletra uma t he fractures are caused by pressurefrom within the cranium, which producesbeveling on th e outer t able. Identifi cation ofthe point of impact and the direction of theforce becomes increasingly di fficult withm ore sev ere t raum a b ut t he sequence ofmultiple impacts usua lly ca n be determinedsince a subsequently produced fracture willnot cross a preexisting one.

    D i r ect t r a u m a i nju r ie s t o t h e cr a n i umoft en oc c ur w hen t he head i s s t ruc k b y amoving object. Tra uma from h igh velocity

    objects, such as bullets and motorized ve-hicles, is seen commonly in clinical cases,but tha t from lower veloci ty objects (e.g. ,bricks, rocks, bludgeons, push carts, wag-ons) is also observed toda y a nd un doubtedlyoccurred i n t he past . D i rect t raum a t o t hecranium a lso occurs i f t he head strikes theground after a fall or jump from a height or

    w hen b al anc e i s l ost a f t er l andi ng on t hefeet . These low veloci ty impacts usual lyresul t i n l i near f rac t ures . Li near f rac t urel ines tend to sweep a round the thick, bony

    buttresses of the cranium (i.e. , the petrousbones, mast oid process, etc.) unless theyapproach t hese area s perpendicularly. Sincethe structural ly weak areas of the craniumar e most prone to develop fracture lines, theunfused crani al sut ures i n chi ldren w i l lreadily separa te t o a ccommodate t he forcesof impact. Alterna tively, in very young chil-d r e n t h e c r a n i a l b o n e s m a y b e n d i n w a r dwithout fra cturing and the depressed defor-mity ma y persist .

    C l ini cal l y, b lunt t raum a i njuri es t o t hec rani um usual l y c ause l i near f rac t ures ofthe vault and the appearance of these frac-t ure l i nes m ay help i dent i fy t he poi nt ofimpact and the mechanism of injury. B luntt raum a t o t he f ront al b one, for exam pl e,produces fracture l ines tha t r adia te thr oughthe frontal sinus, the cribri form plate, andthe orbital roofs, al though transverse frac-t ure l ines a f fect i ng t he t em poral regi onsmay also a ppear. Anterior temporal impactl eads t o f rac t ure l i nes t hat radi at e dow n,across ei ther the orbital plate or the sphe-noid-temporal region. In contrast, lateral orposterior temporal impa ct produces fra cturel ines that ra diate downwa rds ei ther in front

    of or b eh in d t h e p et r ou s p or t i on of t h etemporal bone and extend across the cranialbase. Impact to the occipital bone usual lyproduces fracture l ines tha t r adia te down tot he foram en m agnum or t he jugul ar fora-men, and tha t ma y extend a nteriorly acrossthe cranial ba se. Tra uma to the cranial basemust be severe in order to cause a fracture,since the bone here is heavily buttressed. Abase fra cture is th erefore considered to rep-resent a severe injury.

    After vault fractures, sphenoid fracturesar e the m ost common clinical result of blunttrauma to the cranium (Unger et al . , 1990).

    Unfort unat ely, sphenoi dal s t ruct ures arevery fragi le and thus prone to postmortemdamage as well as to fatal consequences offracture a nd t herefore it may be di fficult toidenti fy sphenoid fractures in ar chaeologi-cal skeletons. Facial fractures, either due todi rect or i ndirect t raum a , are of t en v erycomplex but commonly heal adequately with-

    Fig. 8. Spira l fractur e, 2 months postinjury. Anteriorview is on the left an d latera l view is on the right.

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    out m edi cal t reat m ent . S i nce t he z ygom a,m axi l l a , and orb i t a l m argi n are m ut ual l ysupportive, a fracture of one of these bonesusually involves a fracture of at least one oft he ot hers . Frac t ures of t he nasal b ones,wh ile usua lly not severe, a re not uncommon.These a re often cal led depressed fra ctures(e.g., Filer, 1992) alt hough this description

    refers to the observed deformity of the na sa lbridge, not the type of injury. Cl inical ly,interpersonal violence often produces sma llfra ctures of the nasa l and zygoma tic bones.

    C rush frac t ures of t he c rani al v aul t arecom m onl y seen i n arc haeol ogical hum anr em a i ns a n d a r e ca u s ed b y l ow v el oci t ydirect trauma (Fig. 9). Lesser force is indi-cated by the lack of displacement of bonefragments, w hile great er force is chara cter-ized by inward displacement. A portion ofbone might be completely detached if greatforce is applied, particularly if the object hasa sm a ll striking surfa ce, but more often seen

    in archaeological remains is the incompletedetachment of the bone (Fig. 10). The frac-ture l ine on the ectocranium is usual ly ir-regular and may be comminuted, producinga cobweb or mosaic pattern. The depressedarea i ndicat es t he poi nt of i m pac t , f romwhich l inear fractures r adia te. Cl inical ly,blows from ha mmers, fi replace pokers, and

    the butt ends of axes are commonly respon-sible for incompletely detached depressionfractures, as a re fal ls onto the sharp edge offurniture or concrete steps (Polson et al . ,1985).

    P enet rat i ng i njuri es of t he c rani um arecaused by pointed and edged objects (e.g.,knives, swords) or by bullets. Heavy cutt ing-

    edged w eapons th at ar e used in a choppingmanner will produce crush injuries in addi-t ion t o penetrat ion, a nd furth er injury ma yb e c aused i f t he em b edded w eapon i s re-moved with a twisting motion. This damageis often indicated by splintering of the bonewith outward displacement near the ini t iali m pac t s it e . The t ype a nd s iz e of w oundproduced by a projectile depends upon thesize of the projectile, the speed at which itstrikes the bone, and the distance it travels.Historical skeletons ma y exhibit evidence ofgunshot t raum a , a l t hough t hese i njuri eswould be less severe in terms of bone frag-

    mentation and destruction than those typi-cally found in a metropolitan trauma centertoday. E arly musket bal ls, for example, hadl ow v el oci t y chara c t eri s t ics due t o t heirspherical sha pe and the poor q ual i ty of gunpowder (Butler, 1971). High velocity bullets(3,000 ft/sec) were not developed unti la l m os t 1900, a d a t e t h a t u s ua l ly p la c es

    Fig. 9. Well-healed, crush fracture of the right parieto-temporal region.

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    h u ma n r em a i n s i n a f or en s ic r a t h e r t h a narchaeological context. Details of the inter-pretation of modern gunshot wounds can befound in many textbooks on forensic medi-cine.

    P ossible complica tions of cra nial fr a cturesinclude displacement of bone fra gment s (ma l-union), indirect tra uma injuries elsewhereon the cranium due to the transmission ofimpact force, and soft t issue damage. Thelocation of the impact d etermines th e subse-quent consequences of the injury due to the

    different anatomical structures in the cra-nium. Linear fractures usually involve botht he i nner and out er t ab l es of t he c rani umbut do not involve displacement or depres-s i o n o f t h e b o n e a n d t h u s a r e o f t e n n o tconsidered a s serious a s those injuries result-ing from greater force. Complicat ions canarise, however, due to transmission of the

    force of impact, such as when direct traumato the ba ck of the cra nium produces indirecteffect s on t he orb it a l p la t es . The conse-quences of cranial fractures can be fatal i fthe blood vessels running along the innertables of the cranium (e.g. , middle menin-geal a rteries) a re torn, alt hough this compli-cation is unlikely to be detected with cer-tainty in archaeological remains.

    Mandible

    The mandible forms what is essential lypart of a ring structure, and therefore afracture on one side is commonly accompa-ni ed b y a b al anc i ng frac t ure on t he ot herside. Usua lly the fra cture affects t he horizon-t a l r a m u s o r a n g l e o n o n e s i d e a n d t h econdyle on the opposite side. Fractures atthe a ngle very often communicat e with the

    Fig. 10. Depression fra cture of the cranial va ul t , showing radiat ing a nd concentric fracture l ines.P robably due to low velocity blunt tra uma .

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    roots of the dist a l molar s. Very few ma ndibu-l ar f rac t ures i n anc i ent skul l s hav e b eendescri bed b ut f rac t ures of t he asc endingram us, mandibular a ngle, and condylar pro-

    cesses have been reported (Alexandersen,1967). Asymmetr ica l tooth w ear an d osteoa r-thri t is at the temporomandibular joint arepossible complications of jaw fractures.

    Hyoid

    A l t hough t he hyoi d b one i s not a l w aysrecovered during archaeological excavations,a perimortem hyoid fracture is consideredst rongl y suggest i ve of i nt erpersonal v io-lence t hrough str a ngula tion (Maples, 1986).

    Vertebrae

    The most common fractures of the verte-brae a re due to indirect tra uma, preexist ingdisease, or st ress. A very dist inctive verte-bral fracture is the traumatic separation oft he neural a rch from t he v ert ebral b ody a tt he p a r s i n t er a r t i cu l a r i s (known as spondy-l ol ysi s ; Fi g . 11), w hi ch appears t o b e acommon consequence of habitual physicalstr ess (J imenez, 1994; Mer bs, 1989a, 1989b,1995, 1996). Although th e spondylolysis seenmost often in cl inical sett ings is completesepar at ion, comprehensive surveys of a r-chaeologica l skeletons indicat e tha t t he con-dition begins as incomplete stress fractures

    in adolescents that may heal or, conversely,m ay progress t o com plet e l ys i s b y younga dult hood (Merbs, 1995). The condition m a ybe ini t iated by a n a cute overload event t hatcauses microfra ctures, but i t is general lyag reed tha t th e determining fa ctor is chronictrauma, with repeated stressing promotingnonunion of the microfractures. These fa-t igue fractures appear to have the greatestpopulationa l frequency (a pproa ching 50%)am ong ar ctic-ad apt ed peoples following tra -di t ional l ifew a ys , b ut cl ini cal l y t hey arem ost of t en ob serv ed am ong at hl et es andlaborers whose act ivi t ies involve frequent

    and large stress reversals between lumbarhyperextension and lumbar flexion (Merbs,1989b, 1996). Reported sex differences in theprevalence of th e condition ma y be a ctivity-related (Merbs, 1989b). Spondylolysis maybe unilateral or bilateral in expression, butpredom i nat es i n t he l um b osac ral region,part icularly L5 and, to a lesser degree, L4

    (Merbs, 1996). Complete separation is fre-quent ly accompan ied by ant erior slippa ge ofthe vertebral body (spondylolisthesis), butfunct i onal com pli cat i ons of t h i s are rare(Merbs, 1989b). A fracture with possibly asimilar origin is the traumatic separation ofthe t ip of the spinous process of the seventhcervical or fi rst thoracic vertebra. Referredto as clay-shovellers fracture(Roberts andManchester, 1995), i t may result from thest renuous m uscl e ac t i on associ at ed w i t hshovelling clay, cement, or r ocks.

    More common in a rcha eologica l vertebra et han s t ress f rac t ures are i ndi rec t t raum a

    injuries, such as Schmorl s nodes. Theseresult from bulging of the discs nucleuspulposus, w hich puts pressure on the vert e-bral end plat e a nd leads to bone resorptionin the affected area. Herniat ion of the disctends to occur gradually in adults becausethe nucleus has lost resi l iency, whereas i tmay occur suddenly in younger individuals

    Fig. 11. Lumbar spondylolysis. This separat ion ofthe neural arch and the body at the p a r s i n t er a r t i cu l a r i s i s usual ly at t r ibuted to a fat igue fracture.

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    in whom the nucleus st i l l quite gelat inous(B ullough a nd B oachie-Adjei, 1988). Ind i-rect vertebra l dama ge also can occur in a fa llor jum p ont o t he feet , s i nc e t he forc e of

    impact is carried up from the lower l imbsthr ough the spine.

    Fra ctures secondar y t o pat hology a re alsocommon in the vertebral column. The bestknown clinical example is that of biconcavevertebrae, which result when intervertebraldisks expand into the superior or inferiorsurfaces of vertebral bodies t hat have beenweakened by osteoporosis.4 Similar ly, com-pression flattening of vertebral end platesdue t o sparse, c oarse t rab eculat i on i n t hevertebra l body is a classic feature of sicklecell disease. Due to the greater strength oft he r i m s of t he v ert eb ral end pl at es , t heyma y be spar ed even wh en the vertebral bodyis compress ed.

    Al t hough di rect t raum a i njuries t o t hevertebra e are ra re, hairl ine tra nsverse frac-tures on, or posterior t o, the superior a rticu-lar processes of the second cervical vertebraare worth noting since they can result fromstrangulation (Maples, 1986).

    Ribs and sternum

    Ribs are known t o incur str ess fractures,usual ly a s a result of occupational or simi-l a r ly h a b it u a l l a bor b ut s om et i me s a s a

    conseq uence of persisten t coughing or vomit-ing. Most often, however, rib fractures resultfrom direct tr auma , such a s a blow or a fal lagainst a hard object (Adams, 1987). Clini-cal l y, r i b f ra ct ures are t he m ost com m ontype of thoracic injury a nd ar e observed in60 to 70%of individua ls a dmitt ed to hospitalw i th b lu n t ch es t t r a u m a (C a r r er o a n dWayne, 1989). The direction of the impactusua lly ca n be determined from the loca tionof t he f rac t ure, i . e . , r i b s are usual l y f rac -tured near the angle i f the force is appliedfrom th e front; beside th e spine if th e force isapplied from the back; and beside both the

    spine and the st ernum if t he force is appliedfrom the sides.

    Th e fi f t h t o n i n t h r ib s a r e m os t of t enfractured (Fig. 12). Fracture of the first tothird r ibs and/or the sternum indicat es tha t

    the mecha nism of injury wa s a high kineticforce. D ue t o the flexibi li ty of the rib cage,part icularly in the anteroposterior dimen-sion, the degree of inward displacement ati m pac t m ay hav e b een m uc h great er t hantha t discernable postinjury, a nd thus softt issue damage may have been more severethan might be inferred from the damage tothe bones themselves. Such soft tissue da m-age includes laceration of the pleura, lungs,or i nt ercost a l v essel s, w hi ch w ould hav eb een l argel y unt reat ab l e i n earl ier t i m esand t hus m a y poi nt t o a possib le c ause ofdeat h. Pn eumothorax (the presence of air in

    t he pleural cav i t y) and hem ot horax (t hepresence of blood in th e pleural ca vity) maybe caused by rib fra ctures at a ny level in thet h or a c ic ca g e a n d m a y b e s im il a r ly l if e-thr eat ening. Another serious complica tionof rib fractur e occurs w hen there ar e at leastt w o b r ea k s i n on e r ib . Th is p rod u ce s afree-fl oat i ng f ragm ent and t hus a r i sk of

    4Abiconcave vertebra should not be confused with a butterflyvertebra,which is a congenital malformation.

    Fig. 12. Mult iple healed fractures of the lef t r ibs.The locat ion of the fractures, near the a ngle, suggeststha t the force wa s applied from the front.

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    interna l dama ge, referred to a s fl ail injury.U n f or t u n a t el y, i f t h e s of t t i ss u e d a m a g ecaused by rib fractures is serious enough tocause death, the bony injuries observed in

    the a rchaeologica l skeleton w ould be identi-fi able only a s perimortem fra ctures. Hea ledrib fra ctures in t he a rchaeological recordthus probably represent non-life-thr eat en-i ng t raum a .

    Clavicle

    Cla vicular fra ctures are most often causedby a fall onto the shoulder but occasionallyresult from a fall onto an outst retched han d.The break tends to occur at the junction oft he m i ddl e and l a t eral t h i rds , w i t h dow n-wa rd a nd medial displacement of the latera l

    fragm ent b ei ng a com m on c om pli cat i on.Since cl inical treatment of clavicular frac-tures is usually limited to the use of a slingf or 1 or 2 w e ek s f or p a in r el ie f, h ea l edfra ctures often exhibit some deformity. Mal-al igned clavicular fractures in ar chaeologi-cal skeletons therefore do not necessari lypoint to an a bsence of medica l treat ment.

    Scapula

    Scapular fra ctures are uncommon but a reusually the result of direct tra uma. B oth thefl at and i rregul ar port i ons of t he sc apul amay be involved. Four types are commonly

    described in the clinical literature: 1) frac-t ure of t he sc apul ar b ody, w hi c h m ay b ecomminuted but ra rely displaced because ofthe la rge muscles holding t he bone in pla ce;2) fracture of the neck, which may lead todownward displacement of the glenoid; 3)and 4) fractures of the acromion and cora-coid processes, respectively, which ra ngefrom si mple crac ks t o com m inut i on andw h i c h m a y b e a s s o c i a t e d w i t h d o w n w a r ddisplacement. Although none of these inju-ries is usually considered serious, a possiblecomplica tion of scapula r fra cture, especiallyi f t h e i nju r y occu r s on t h e l ef t s id e, i spneumothorax (Carrero and Wayne, 1989).

    Humerus

    The most common humeral fractures inadults affect the neck, great er t uberosi ty,and shaft . Neck fra ctures are most commonin older women in whom osteoporosis hasweakened the bone. Indirect t ra uma from a

    fal l onto an outstretched hand is the usualcause and in more than 50%of these casesthe fra cture is self-sta bilized through impa c-tion. Direct tr a uma , in the form of a fall onto

    the shoulder or a blow, ma y cause fra cture oft he great er t ub erosit y. S haf t f rac t ures aremost common in th e middle third of the boneand may be due to direct or indirect trauma.The proximal half of the shaft is a commonsite of fra cture seconda ry to pat hology, sucha s w h en t h e b on e h a s been in va d ed b ym et ast a t i c di sease. C ompli cat i ons of hu-meral shaft fractures include displacement,nonunion, an d injury to the radia l nerve.

    I n con t r a s t t o t h e p a t t er n ob se rv ed i nadults and described above, humeral frac-tures in children tend to occur at the dista l

    end, affecting the supracondylar, epicondy-l ar, and condylar regi ons. Suprac ondyl arfra ctures are indirect tra uma injuries causedb y a f a ll o n t o a n ou t s t re t ch ed a r m , w i t hdisplacement occurring posteriorly. Compli-c at i ons i nc l ude m al uni on, dam age t o t heb ra c h ia l a r t e r y, a n d t e a r in g of t h e joi ntcapsule with hemorrha ge into the joint a ndsurrounding t issues. Epicondylar fracturesa r e u s ua l ly m ed ia l a n d m a y r es u lt f r omdirect trauma but more often from avulsionb y fl exor m usc l es i n a fa l l . I f t he av ul sedfragment enters the joint, which occurs fre-quently in children, complications in terms

    of reduced function and osteoar thri t is usu-ally ensue. This injury may also cause dam-age t o t he ul nar nerve. C ondyl ar f rac t uresar e uncommon but a lso tend t o result from afall . In contr a st t o the medial involvement inepicondyla r fra ctures, the lat eral portion, orcapitulum, is usual ly involved in condylarfractures. D isplacement is n ot uncommonand this injury is often complicated by defor-mity, nonunion, a nd osteoart hritis.

    Ulna

    Ul nar f rac t ures are not espec i al l y c om -

    mon cl inical ly, but when they occur t heyusual ly a f fect t he ol ecranon or t he shaf t .Olecranon fractures are more common inad ults an d result from the direct tra uma of afa l l ont o t he poi nt of t he elb ow . S everit yranges from a simple crack to comminutionand the injury ma y be complicat ed by n on-union and ost eoart hri t i s . D i aphyseal f rac -tures can result from ei ther direct or indi-

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    rect t raum a (Fi g . 13). They are prone t osevere displacement, malunion, nonunion,a nd t o infection becaus e of the bones proxim-ity to the sur face of the skin. Fra cture of theproximal sha ft of the ulna is often a ssociat edwith the dislocation of the radial head. Thisinjury is referred to as a Monteggia fra cture-dislocation. It is usua lly ca used by a fa ll ontoan outstretched hand with forced pronation,b ut i t m a y a l so b e caused b y a b low t o t heback of the upper forearm (i .e., a parry fracture). Deformity commonly chara cter-

    izes this injury in archaeological skeletonssince t he f rac t ure c annot b e properly re-duced without sur gery.

    Radius

    Another forearm injury, the G a leazzi frac-ture-dislocation of the radius, is more com-mon cl inical ly than is the Monteggia frac-ture-dislocation. It is also usua lly caused bya f a ll o n t o t h e h a n d , a n d s im il a r ly i t i sdifficult to rea lign without su rgical interven-tion. The fracture occurs near the junction oft he m i ddl e and di s t a l t h i rds of t he radi alshaft and is accompanied by dislocation of

    th e inferior ra dio-ulna r joint . The most com-m on r a d i us f r a ct u r e o ccu r s a t t h e d is t a lsha ft a nd is ca lled the Collesfra cture. Clini-cally, it is the most common of all fracturesi n a d u lt s ov er t h e a g e of 40, e sp eci a ll yfemales, and is nearly a lway s caused by theindirect t ra uma of a fa l l onto the ha nd. Thebreak usua l ly occurs about 2 cm a bove thedi s t a l ar t i c ul ar surfac e of t he radi us , and

    the distal fragment is posteriorly displacedand usual ly impacted. This injury may beassociated with fracture of the styloid pro-cess of the ulna. Although fractures of thedistal ra dius, such as t his, are one hundred-fold more frequent tha n a re fractures of theproximal radius (Knowelden et al . , 1964),frac t ure of t he radi al head a l so c an resul tf rom a fa l l on an out s t ret c hed hand. Ob -serv ed m ai nl y i n young adul t s , i t usual l yappears as a c rac k w i t hout di spl ac em ent .Comminution is possible, however, and in

    such cases th e injury ma y be complica ted byosteoar thri t is. In contra st to these indirectt raum a i njuries , a s im ple f ra ct ure of t heradi al shaf t , som ew hat l ess c om m on t hanthe fr a cture-dislocation injuries, usua lly re-sults from direct trauma.

    Malunion is the most common complica-t i on of r a d i us f r a ct u r es , a n d a b s en ce ofm edi c al t reat m ent c annot b e presum ed i fdeformity is observed since redisplacementis very common clinically within a week offracture reduction. In archaeological speci-m ens, a t l east one s t udy ha s report ed t ha tra dius fractures ra rely healed wit hout defor-

    mity (Gra uer a nd Roberts, 1996).Pelvis

    Isolat ed fra ctures of the pelvic bones mostcommonly appear on the superior and/orinferior ischio-pubic ramus and the wing ofthe i lium. These fractures ar e q uite benignunless displacement occurs. More seriouspel vi c f ract ures a re t hose t ha t di srupt t he

    Fig. 13. Healed obl ique fra