As submitted by the proposer:
Gunshot wound interpretation, especially of the skull, has been extensively studied in forensic anthropology. Most studies have taken a retrospective approach, whereby information from autopsy reports or forensic anthropology reports are mined for data about predictive patterns. This approach is admittedly problematic due to the number of extrinsic variables present. These variables include factors such as velocity of the projectile, distance of the weapon to the victim, type of firearm, bullet caliber, and bullet construction. In retrospective studies, there is no way to know what many of these variables were, rendering the results less reliable. An experimental approach is therefore more reliable as such variables can be controlled for.
This project will experimentally test the effect that bullets of two different constructions (hollow point vs. full metal jacket) have on human skulls in terms of fracture pattern and amount of damage, as assessed by centimeters of total fracture. These different bullet types are designed to either fully penetrate with no fragmentation (full metal jacket) or penetrate and fragment upon contact (hollow point). Therefore, we hypothesize that damage caused by hollow point ammunition will be greater, which has implications for fracture interpretation. Skulls will be divided into four groups, characterized by the type of bullet used and the location of the entrance wound on the cranium. This will allow tests of not only bullet construction but whether entrance wound location of different areas of the skull (side of head versus forehead) are a factor as well. Human heads will be acquired from LifeLegacy Foundation, an organization that provides willed human remains for trauma and other scientific research for the greater public good.
Statistical analyses will include a two-way ANOVA to determine both the differences in fracture length by entrance location and by bullet type, as well as the interaction between them (comparing all four location/bullet type groups). Differences in fracture patterns (linear, concentric) between the bullet types (hollow point vs. jacket) will be examined using chi-square analysis with statistical significance set at p<.05. Following fracture analysis, all fractures will be photographed and an atlas with the photographs and all relevant variable information (velocity, weapon type, bullet type, etcetera) will be constructed, with the goal of adding results from future similar experiments that test other extrinsic variables. This atlas will be made available to the forensic science community, to aid practitioners with skeletal gunshot wound interpretation. Further, project results will be disseminated via presentations at the American Academy of Forensic Sciences Annual Meeting; as well as via publications written for major forensic science peer-reviewed journals.
Note: This project contains a research and/or development component, as defined in applicable law.