Understanding the mechanism of injury associated with long bone fractures through dynamic bending impact

Blunt force trauma may result from homicide and assault cases, child abuse and motor vehicle accidents. Such incidents often result in skeletal trauma. Trauma to the lower limbs due to bending forces often involves a fracture pattern known as a butterfly or wedge fracture. Forensic analysis of the butterfly fracture aids in the establishment of directionality of the force applied. Currently, forensic anthropologists employ a method dictating that the base of the butterfly fragment pertains to the side of impact, while the apex of the fragment pertains to the opposite side of impact. Recent studies have demonstrated that this theory leads to erroneous forensic reconstructions as it assumes that all butterfly fractures are produced due to bone failing in tension. Furthermore, it requires the presence of a detached piece in order to be applicable, which is also the case for other proposed methods. The current study explores the biomechanics involved in the production of butterfly fractures by conducting 3-point bending impacts through a drop apparatus. It also investigates the accuracy of current and proposed forensic methods and aims at establishing a more reliable method of inferring directionality from the fracture pattern. From the sample fractured in this study, 11.8% of the fractures produced were tension wedges and 14.7% were compression wedges. When applying the existing methods of inferring directionality to the fractured sample, the accuracies ranged from 5.9% to 59%, while the method developed during this study achieved an accuracy of 97.1%. These results highlight the need of considering compression wedges during forensic reconstructions and understanding the impact of employing methods conceptualised on the assumption that all butterfly wedges are produced in tension.

Grantor

Department of Pathology

Year dc:date.issued

2019

Author dc:creator

• Emrith, Toshika Sheshna

Advisors dc:contributor.advisor

• Mole, Calvin
• Heyns, Marise

• Biomedical Forensic Science

Handle dc:identifier.uri

http://hdl.handle.net/11427/31392

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/31392