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Forensic Science

jou r nal h o mep age: w ww.els 1. Introduction

One of the main responsibilities of the forensic pathologist,besides determining the cause of death, is to document injuries andto deduce how the injuries occurred [1]. The interpretation of car-to-pedestrian accidents is a habitual and challenging task for aforensic pathologist. Although certain patterns of injuries inpedestrians can clearly elucidate the circumstances of a trafcaccident, determine the direction of hit and injury mechanism,there is still lack of satisfactory methods for reconstructing theaccident or determining clearly the sequence of the sustainedinjuries [2].

Decollement is believed to be a very good indicator of run-overaccidents [3]. It is most often produced by a tangential forceapplied on a body part by a turning wheel that rolls across it. Theskin is then torn-off from the underlying muscular fascia, resultingin a pocket formation lled with blood and fat tissue [4].However, decollement can be produced also by an oblique ortangential force applied on a person in an erect position [3], orperpendicular force during free fall impact [5]. Therefore, the

interpretation of decollement must be carefully given, as it hasbeen demonstrated that the mechanism of the injury is morecomplex than was believed before [5]. Yet, decollement in forensicpractice has been shown useful in reconstructing lethal accidentspertaining to motor vehicle and suicide victims [3,6].

The authors present a unique case of decollement that resultedfrom a run-over accident. Along with the description of thedecollement, this case report offers an explanation of the possiblemechanism of injury that arose both from the autopsy ndings andthe analysis of the video material from the local surveillancecameras and scene photos of the accident.

2. Case report

An 85-year-old man was fatally injured after being run over by atank truck while walking on the roadway. The accident happenedwhen the road tanker just started moving slowly at the momentthe trafc light turned green. The victim was found lying facedown, beneath the rst pair of trailer sections wheels (the cabinsection of the road tanker had two axles and two pairs of wheels,while the trailer section had three pairs of doubled wheels placedon three axles), in a nearly longitudinal position with the headoriented toward the cabin.

Not one of the people present at the accident spot provided areliable eyewitness account. The forensic pathologist was not

Car accident

Surveillance cameras

Legal medicine

brought to the fatal injuries. The authors concluded that the expulsion of the jejunum was produced by a

combination of two movements: a forward passage that created the decollement and detachment of the

jejunum and a backward movement that completed the expulsion of the jejunum through the open

fracture of the ankle.

This case report evidences the importance of the forensic pathologist and a correct and detailed

investigation of injuries in reconstructing an accident, as well that of surveillance cameras as

investigation tool in forensic cases.

2013 Elsevier Ireland Ltd. All rights reserved.

* Corresponding author. Tel.: +385 98 260 339.

E-mail addresses: anja.petaros@yahoo.com, anja.petaros@medri.uniri.hr

(A. Petaros).

0379-0738/$ see front matter 2013 Elsevier Ireland Ltd. All rights reserved.http://dx.doi.org/10.1016/j.forsciint.2013.02.007Case report

Car-to-pedestrian accident with a uniq

Valter Stemberga a, Anja Petaros a,*, Anita Barisic b

aDepartment of Forensic Medicine and Criminalistics, Rijeka University School of MedibRijeka University, School of Medicine, Brace Bracnhetta 20, 51 000 Rijeka, Croatia

A R T I C L E I N F O

Article history:

Received 22 May 2012

Received in revised form 23 September 2012

Accepted 4 February 2013

Available online 1 March 2013

Keywords:

Decollement

A B S T R A C T

The authors present a uni

over by a tank truck. Whil

the preliminary ndings a

left hemithorax to a woun

mesentery protruded.

The article offers an in

probable decollement me

help of surveillance came decollement injury

iran Coklo a, Ivan Sosa a, Alan Bosnar a

, Brace Bracnhetta 20, 51 000 Rijeka, Croatia

case of decollement injury found on an 85-year-old victim that was run-

ternal examination evidenced multiple severe injuries, autopsy conrmed

evealed also the presence of an extensive decollement that spread from the

the left ankle, through which parts of the small intestines and pertaining

pretation of the injuries sustained by the victim, focusing on the most

ism. The forensic pathologist in this case could rely also on the valuable

of a nearby bank ofce that helped to better understand the events that

International

evier . co m/lo c ate / fo r sc i in t

called upon to inspect the accident scene, so any interpretation andreconstruction of the injury mechanisms depended on the carefulautopsy examination. This was later supplemented by accidentscene photographs and videotapes of a nearby surveillance camerathat helped to conrm the pathologists ndings and reconstructbetter the mechanism of the sustained injuries.

2.1. Autopsy ndings

The external examination evidenced multiple severe injuries,especially to the head that was extensively deformed, showingcomminuted fractures with many bone fragments missing and anearly empty cranial cavity. A wide-ranging laceration was presentin the fronto-temporal region. There was an excoriation on the leftside of the face. The back showed diagonal patterned abrasionscorresponding to tire tread marks. Two more soft-tissue injurieswere present on the left lower extremity a laceration behind theknee and an open wound resulting from the fracture of the ankle.

Besides the skull, there were fractures observed in the leftscapula, both right and left 1st to 12th ribs, sternum, thoracicvertebrae (Th6 and Th7), left ilium and sacroiliac joint, both knees,and left foot.

Internal examination showed severe injuries with the displace-ment of internal organs and ruptures of the heart, both lungs,thoracic aorta, liver, spleen, intestines and diaphragm, as well ascontusion and displacement of the kidneys.

The most interesting autopsy nding was the presence of anextensive decollement that spread from the left hemithorax to theleft ankle wound, through which parts of the small intestines andpertaining mesentery protruded (Fig. 1).

During external examination the skin detachment was ob-served only in the left thoracic region, while its range became

apparent during the process of skin preparation in the left leg andabdomen. The decollement along the medial and anterior aspect ofthe left leg communicated with the abdominal cavity andcontinued to the pocket formation of the left thoracic region.Through the extensive subcutaneous hemorrhagic tunnel thejejunum with related mesentery reached and protruded on the leftankle (Fig. 1).

2.2. Surveillance camera ndings

The forensic pathologist in this case could rely also on thevaluable help of surveillance cameras of a nearby bank ofce. Therewere two cameras: one static outdoor camera and one rotatingoutdoor camera. Unfortunately, the angle covered by the staticcamera has not allowed the visualization of the complete scene ofaccident and neither of the complete truck, but only its bottom(Fig. 2). On the other hand, it was enough to gain information onthe sequence of events and on the number of wheels that ran overthe victim.

The rotating camera was recording a series of different anglesduring a minute interval that meant that it was unable to record theexact moment of the accident, as it was lming a different fraction ofthe bank surrounding area (Fig. 2). However, the mobile camerarecorded the moments that followed the accident, evidencing theposition of the victims body in relation to the truck immediatelyafter being run over, and after the police intervention.

Additional limitation to the analysis of the video material wasthe poor resolution of the video data.

The static camera evidenced that the victim fell under a heavytanker after a lateral contact with the vehicle. After the fall, he wasrun over by two pairs of wheels (the second pair of cabins wheelsand the rst pair of trailers wheels) (Fig. 3).

) a

t)

V. Stemberga et al. / Forensic Science International 228 (2013) e67e70e68Fig. 1. Wound on left ankle, through which ileum protrudes (left

Fig. 2. Angles covered by the two cameras: static camera (left) and mobile camera (righjust the bottom of the truck).nd extensive decollement visible after skin preparation (right).

. In both, the tanker truck position is visible (on the static camera it can be observed

er b

V. Stemberga et al. / Forensic Science International 228 (2013) e67e70 e69Fig. 3. Screenshots of the videotape showing the victim (arrow) run ovWhen the driver realized what happened he stopped thevehicle, in the instance when the rst pair of trailers wheels waslocated above the victims thorax. In order to liberate the corpse,after the police intervention, the driver made a reverse movement.The backward movement was detected when comparing therotating cameras records before and after the arrival of police(Fig. 4).

3. Discussion

In a number of motor-vehicle fatalities, the forensic pathologistis asked to provide an objective interpretation of the injuriessustained by the victim and to deduce what mechanisms causedthe injuries relying exclusively on the results of an autopsy [7].Such situations are very often in hit-and-run cases or incircumstances where there is little evidence on the accident (lackof or unreliable witness statements, lack of scene ndings).However, in most cases the autopsy nding alone is not enough toreconstruct properly the accident dynamics. We presented a run-over case with a unique pattern of injury, in which it was possibleto compare and verify the pathologists preliminary report, whichwas based exclusively on a careful investigation of the sustainedinjuries, with the images of a local surveillance camera thatobjectively recorded the dynamics of the event.

The injuries found on the corpse suggested that the person wasrun-over by a vehicle that passed across the left side of the body(from the left feet to the head). Tire tread marks visible on thevictims back indicated that the victim was in prone position whenthe truck ran over him. Given that the majority of injures werelocalized on the left side of the body, the bilateral facture of the

Fig. 4. Screenshot of the rotating camera showing the position of the body upon arrival of(right).y two wheels (circled): the second cabins and the rst trailers wheel.knees suggested that the person fell on his knees when hit, so hewas most likely walking in the same direction of the fuel tanker.This was later conrmed by the videotape of the surveillancecamera. There was no internal or external evidence that couldsuggest the direction of the hit, but the camera showed that thevictims fell under the wheels when walking side by side with thefuel tank (most probably his umbrella get stuck in the posteriorpart of the cabin while the truck started moving, pulling the victimunder the wheels).

The autopsy revealed an extensive comminuted fracture of theskull that was produced by the passage of the large vehicle over itas shown in the video records. The extensiveness of fractures andinternal injuries (dislocation, laceration and rupture of internalorgans) was in line with other run-over cases and impact withlarge vehicles [8]. Although the thoracic region was extensivelydeformed and fractured, there was a concentration of fractures inthe middle thoracic region (sternum, 6th, 7th thoracic vertebrae,scapula) indicating a longer period of compression. It has beendemonstrated that the extent of chest compression and relatedinjuries is dependent on the loading time, so a longer concentrationof a loading over a localized area results in greater compression ofthe chest and more extensive fractures [9], like in our case. Theinjuries of the victim thus suggested that the vehicle mostprobably slowed down or stopped when running over the thorax.This nding has been conrmed by the video records that showedthe truck stopping over the victims trunk. However, the autopsycould not conrm multiple passes over the body: tire imprints,present on the victims back, corresponded to at least one run-overbut could not exclude multiple passes [8]. In addition, sinceextensive internal injuries and fracturing can occur also with a

police (left) and after the truck has made a reverse movement to liberate the corpse

International 228 (2013) e67e70single pass [8], the extent of fragmentation and organ dislocationpresent in our case could not be useful to conrm multiple passes.So in this instance the videotape helped again to complete thendings of the autopsy, as two passes and a reverse movementover the body have been recorded by the static camera.

The most interesting nding of the autopsy was the uniquedecollement injury present along the anterior and medial aspect ofthe left leg, left abdomen and left thorax, through which a part ofthe jejunum reached the left ankle. As this type of injury has not yetbeen described in literature, the forensic pathologist tried toreconstruct the possible mechanisms of the decollement relying onthe injuries and evidences present on the victims body. Thedecollement, together with the patterned band of abrasions (tiretread marks), evidenced the run-over mechanism. Althoughdecollement can be observed also as an initial collision injurywhen the victim is still in an erect position [3] (e.g. lateral hit), theextensiveness and the medial (internal) location of the decolle-ment in our case, went in favor of the run over mechanism ofinjury. The decollement was produced by a force parallel to thesurface produced by the tire that pulled across the extremity andthe trunk of the victim. The same tangential force caused theshearing of the mesentery that is commonly pulled off by a severetraction force exerted on the membrane [1]. These, along withtransaction of the jejunum that occurred 25 cm distally to theTreitz ligament, allowed the small intestine to be easily displaced.The mobility of the loops of the small intestine facilitates itsdislocation during blunt force trauma accidents [1] that onlyoccasionally produce the rupture of abdominal viscera. Duringrun over accidents thoracoabdominal crushing injuries most oftenresult in dislocation of the bowl segments into the thorax withrupture or laceration of the diaphragm [8,10]. In our case, thedislocation occurred in the left hemithorax, but the jejunum andits mesentery were displaced also through the ruptured abdomi-nal wall that acted as locus minoris resistantiae into thedecollement of the leg, through which it reached the left ankle.So, the decollement injury and the hemorrhagic tunnel had to beformed prior to intestinal displacement. In addition, a strong andlong lasting force was necessary to enable the protracted passageof the jejunum from the abdomen to the left ankle. The forceexerted by a single pass could bring to the formation of thedecollement (tangential force), as well the displacement of theabdominal viscera due to the fact that the wheel while movingforward, produces also a backward force. In case that there was alonger spinning over a persons corpse, the movement and forcesexerted by a spinning tire could push the detached intestines inthe preformed tunnel. However, the camera did not evidence anyspinning movement so the forensic pathologist concluded thatthere was small probability that a single pass could push thejejunal convolutes till the wound of the ankle. A more probablescenario, conrmed also by video records, was that the expulsionof the jejunum was produced by a combination of movement: theforward passage created the decollement and the detachment ofthe jejunum, and probably pushed a part of the jejunum in thepreformed tunnel as well in the thoracic region, while thebackward movement completed the expulsion of the jejunumthrough the open ankle fracture.

In conclusion, the autopsy ndings helped to elucidate anumber of queries regarding the accident: the position of theperson in relation to the vehicle, the fact that the person was run-over by a large, slow moving vehicle, the fact that the vehicle mostprobably stopped or exerted for a longer time a force over themiddle thorax of the victim. The autopsy nding could not help toestablish if the person was hit by the anterior or the lateral side ofthe vehicle, neither with certainty the number of passages over thebody. These queries have been solved with the analysis of the videomaterial. However, although the video material conrmed and

V. Stemberga et al. / Forensic Sciencee70elucidated the majority of the pathologists ndings, the realmechanics of the decollement remains uncertain, although theauthors tend to the idea that the reverse movement was essentialfor the nal ejection of the jejunum convolutions through the leftankle that could not happen just by the passage of two slow-moving wheels with no spinning movement over the body.

4. Conclusion

This case report evidences the importance of the forensicpathologist and a correct and detailed investigation of injuries inreconstructing an accident, as well that of surveillance cameras asinvestigation tool in forensic cases [11]. Forensic pathologists oftenhave to recreate the dynamics of an accident based only on theautopsy ndings and their interpretation, relying on the theoreti-cal knowledge and practical experience of the specialist. In thiscase the forensic pathologist was able to test his conclusion againstthe actual records of the event captured by the surveillancecameras. In the authors opinion, surveillance cameras should startto be used, whenever possible, as an auxiliary tool by forensicpathologists, because they can objectively conrm some supposi-tions and theories made by the pathologist that cannot bedenitely proven by autopsy examination. After an objectiveverication, these can consequently be accepted as valid andapplied in the interpretation and reconstruction of similaraccidents.

The study has also shown how surveillance cameras addedinformation to the interpretation of the decollement, but have notsucceeded to completely solve its origin. Thus, the authorshighlight once again the complexity of the mechanism ofdecollement, emphasized also by previous studies [5]. More casestudies on decollement injuries, their origin, characteristics andmechanics must be reported. Furthermore, there is a need toconduct experimental studies on the biomechanics of decollement,as well as further research on the biomechanics of abdominalinjuries taking in account the inuence of the spine, the non-homogenous characteristics of the abdomen and also differentimpact and compression sides [12].

References

[1] V.J. DiMaio, D. D DiMaio, Forensic Pathology, second ed., CRC Press, Boca Raton,2001.

[2] G. Teresinski, R. Madro, Evidential value of injuries useful for reconstruction of thepedestrian-vehicle location at the moment of collision, Forensic Sci. Int. 128(2002) 127135.

[3] D. Metter, Decollement as initial collision injury, Z. Rechtsmed. 85 (1980)211219.

[4] G. Teresinski, Injuries of the thigh, knee and ankle as reconstructive factors in roadtrafc accidents, in: J. Rich, D.E. Dean, R.H. Powers (Eds.), Forensic Medicine of theLower Extremity, Humana Press, Totowa, 2005, p. 318.

[5] P. Strejc, J. Sachl, A. Vlckova, J. Dressler, D. Vajtr, Another mechanism of decolle-ment, Soud. Lek. 55 (2010) 5153.

[6] Y. Nishitani, T. Hayase, Y. Yamamoto, K. Yamamoto, An unusually extensivedecollement in the back in a non-trafc-accident victim; probably produces bya glancing blow by a falling weight, Res. Prac. Forensic Med. 44 (2001) 257260.

[7] Y. Nishitani, O. Shunichiro, K. Suzuki, K. Imabayashi, R. Katada, H. Matsumoto, Thediscrepant severity of external and internal injuries in a trafc accident: thecushioning effect via a human body against direct impact, Am. J. For. Med. Pathol.30 (2009) 186187.

[8] D.A. Wolf, Motor vehicle collision, in: D. Dolinah, E. Matshes (Eds.), ForensicPathology: Principles and Practice, Elsevier Academic Press, London, 2005 , pp.276281.

[9] C. Arregui-Dalmases, R. Teijeira, J. Forman, Injury biomechanics as a necessarytool in the eld of forensic science: a pedestrian run-over case study, Forensic Sci.Int. 198 (2010) e5e9.

[10] K.A. Mansour, Trauma to the diaphragm. A retrospective analysis of 41 patient,Ann. Chir. Gynaecol. 84 (1995) 261265.

[11] S. Irsay, Surveillance Cameras Play Increasing Role as Investigative Tool. Availablefrom: http://archives.cnn.com/2002/LAW/10/21/ctv.cameras/ (accessed10.08.11).

[12] K.U. Schmitt, P. Niederer, M. Muser, F. Walz, Trauma Biomechanics, Springer,Leipzig, 2007, pp. 149160.

Car-to-pedestrian accident with a unique decollement injuryIntroductionCase reportAutopsy findingsSurveillance camera findings

DiscussionConclusionReferences