Perimortem Fracture Patterns in South-Central Texas: A Preliminary Investigation into the Perimortem Interval
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Establishing a relationship between skeletal trauma and time since death is one of the most frequent requests made of forensic anthropologists. To this end, skeletal biologists and forensic anthropologists typically distinguish three gross timeframes when classifying traumatic episodes: antemortem, perimortem and postmortem. The perimortem interval, which occurs around the time of death, is poorly understood (Sauer, 1998). There have been several studies investigating long bone fracture characteristics during the perimortem interval (Weiberg, 2005; Bell et al., 2006; Janjua and Roberts, 2008), but none have been undertaken in the unique climate of southwest Texas. To imrove understanding of perimortem bone changes, 50 pig femora were allowed to weather at the Texas State Forensic Anthropology Research Facility at Freeman Ranch, in San Marcos, TX for up to 18 weeks (PMI=126 days. A portion of the sample was broken at regular 2-week intervals by application of a known dynamic force, and the resulting fracture outlines, angles, and edges, were examined and documented. Analysis showed that there was no statistically significant change in the frequency of fracture patterns or fracture angles between bones broken shortly after death (PMI=0), and those broken in the subsequent trials. There was, however, a statistical trend toward rougher fracture edges. This study demonstrates the difficulty in estimating whether fractures occurred during the perimortem interval. Future studies should examine whether these observations hold for different seasons and different environments.