In forensic anthropology, skeletal trauma is a growing area of analysis that can contribute important evidence about the circumstances of an individual's death. In bioarchaeology, patterns of skeletal trauma are situated within a cultural context to explore human behaviors across time and space. Trauma analysis involves transforming observations of fracture patterns in the human skeleton into inferences about the circumstances involved in their production. This analysis is based on the foundational assumption that fracture behavior is the nonrandom result of interactions between extrinsic factors influencing the stresses placed on bone and intrinsic factors affecting bone's ability to withstand these stresses. Biomechanical principles provide the theoretical foundation for generating hypotheses about how various extrinsic and intrinsic factors affect the formation of fracture patterns, and about how these factors can be read from fracture patterns. However, research is necessary to test and refine these hypotheses and, on a more basic level, to document the relationships between "input" variables of interest and fracture "outputs." One research approach involves the use of forensic and/or clinical case samples. Case-based approaches are important because they provide data from real scenarios and contexts that may be similar to those encountered in unknown cases. However, a limitation is that input variables are not directly measured or controlled and therefore cannot be precisely known. Therefore, case-based approaches offer incomplete means of hypothesis testing. Over the past decade, anthropologists have increasingly addressed this problem using prospective, experimental approaches. Experimental research provides the advantage of investigating fracture patterns generated under known, replicable, laboratory-controlled conditions. While this type of research is believed to be most applicable to forensic cases when it is conducted on unembalmed postmortem human subjects (PMHS) within the perimortem interval, to date the majority of experimental studies have involved nonhuman models. Given micro- and macro-structural differences between species, it is yet unknown how results obtained in nonhuman bones scale to human bones. Experimental studies on PMHS are therefore warranted to test hypotheses and develop reference points for how fracture patterns form in response to various loading inputs. The purpose of this dissertation is to document and evaluate basic relationships between several forensically relevant input variables and fracture behavior outputs through a series of blunt force impact experiments on human crania and femora. Part one of this dissertation investigates cranial fracture behavior in relation to the input variables of point of impact, number of impacts, impact surface, and kinetic energy. Part two investigates the relationship between impact direction and fracture behavior in the femur. The papers comprising this dissertation are united by three common goals: 1) to investigate fracture formation, including how and where fractures initiate and propagate relative to the impact site; 2) to document and compare fracture behavior in response to known input variables; and 3) to evaluate fracture features described in reference literature and gather evidence of their utility in reconstructing these input variables. This research advances understanding of the interplay between impact variables and fracture behavior in cranial and postcranial blunt force skeletal trauma. Furthermore, this study contributes reference data associating known loading conditions with resultant fracture patterns in human material. This type of data is necessary to build interpretive and methodological theory in anthropological trauma analyses.
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