Identifying primary, secondary and tertiary blast force skeletal trauma patterns for forensic recovery applications
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Abstract
Blast injuries are more commonplace today than in the past, due to the current sociopolitical climate and tactical mode of modern warfare. Yet, skeletal blast trauma has not been well researched, and forensic anthropology literature regarding blast trauma is sparse. Skeletal trauma and identifying the corresponding mechanism is a quintessential aspect of forensic anthropology. Blast trauma is distinguished into four categories: primary, secondary, tertiary and quaternary, based on blast’s impact on the body and the mechanism by which trauma is sustained such as contact with the blast wave. These levels and severity are dependent upon variables including distance from the explosive, type of explosive and crowding of people or objects and enclosure of the blast site. Primary blast trauma is caused by contact with the explosive blast wave, secondary is associated with the penetration of fragments from the explosive like shrapnel and tertiary is caused by contact with the blast wind which often results in bodily displacement. This study aims to expand the literature that exists for skeletal trauma and anthropology, by examining and identifying patterns at the primary, secondary and tertiary mechanism levels of skeletal blast trauma, as well as the post-blast dispersion pattern. The experimental specimens consisted of ten clothed whole domesticated pigs (Sus scrofa) to serve as proxy for humans and two different explosive attack scenarios were utilized. The first was a standalone improvised explosive device, IED, attack and the second was modeled after a suicide bomber scenario fitted with shrapnel. Additionally, three specimens were fitted with Kevlar®️ vests to examine trauma pattern differences and amount of skeletal trauma between specimens. Both scenarios were carried out with associated furniture and constructed wooden enclosure on an explosive testing range to recreate a semi-enclosed crowded city environment, which is a common target of terrorist attacks. Following the blasts, a forensic recovery team assisted with the recovery and mapping of remains. It was hypothesized that the aforementioned three levels of blast force trauma would have distinct trauma patterns which could then be applied in forensic analyses of human remains found at blast sites as well as recreating the scene pre-blast.
Different patterns of trauma corresponding to mechanism levels were indeed observed, as well as an increase in trauma among the pigs fitted with Kevlar vests, especially of the vertebral column; 61 elements from vested pigs sustained fractures while only 45 elements of non-vested pigs sustained fractures. Observed primary trauma included comminuted, oblique and spiral fractures in the long bones, diastatic fractures of the cervical vertebrae and rib fractures. Secondary trauma consisted of ballistic trauma and pelvic fractures. Tertiary trauma included oblique, comminuted and linear fractures in various elements; the most frequently fractured elements were the ribs and vertebrae. All vested pigs presented ballistic trauma, as well as the most vertebral fractures overall, especially in the lower thoracic and lower cervical vertebrae. There was a disparity in the amount of observed trauma between the two scenarios. The suicide bomber scenario presented more trauma with 8.18% of all elements fractured, while only 1.23% of elements were fractured in the IED scenario. The mapping of the scene provided a new insight observed in both scenarios in the processing of a blast site which could help in reducing the duration of recovery while maximizing the yield of recovery. 85% of all debris and remains were found behind the seat of the blast rather than in front, which is what is typically expected. The observed trauma, especially in the vested pigs, furthers the current understanding of the biomechanics of blast trauma fractures and injuries.
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Attribution 4.0 International