The effect of burning on pre-incineration trauma in bone

Chang, Enya

The effect of burning on pre-incineration trauma in bone

Thesis / Dissertation

2023

Abstract

The act of burning is a common method of destroying and concealing evidence which may include dismemberment of the body. Saws used during dismemberment leave characteristic marks on bone, the analysis of which can assist in forensic casework. Research that has been conducted to date, provide minimal information on controlled temperatures to analyse and distinguish pre- and post-burning trauma marks. The aim of this research was to assess and compare morphological differences of pre-existing bone trauma before and after burning at various controlled temperatures. In this research, a back saw (tenon saw) was used to manually inflict trauma on de-fleshed Ovis aries femur bones (n = 18). These bones were later exposed to heat at controlled temperatures of 400°C, 600°C and 800°C for 20 minutes. Three different cut marks including a shallow false start, incomplete cut and a complete transection of the bone were inflicted on the mid-shaft of each bone specimen through which 54 lesions were analysed. Differences in saw mark characteristics of the cut surfaces before and after exposure to heat were investigated and compared. The following characteristics were examined: blade drift, bone islands, breakaway spurs, exit chipping, harmonics, kerfs, pull-out striae, striation regularity, tooth hop and profile shape. Quantitative analyses were conducted using macroscopic techniques and stereomicroscope to examine the specific characteristics of the different saw marks. All pre-existing trauma except one cut mark (shallow false start) survived after the burning process. The shallow false start was lost during the burning process and could not be recovered. The saw marks were distinguishable from heat-related fractures in all temperature groups. In some cases, characteristics such as exit chipping, pull-out striae and striation regularity were enhanced post-burning. Nonetheless, the post-burning survival and detection of saw marks can be obscured which may affect the visibility of sharp force trauma. Therefore, additional research for instance burning the bones at different durations and increasing the sample size should be examined. Furthermore, information on other factors and variables such as bone type or burning environment can be collected to create a database to increase accuracy of saw mark analysis.

Keywords

Biomedical Forensic Science

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