Analysis of entheseal changes and cross-sectional bone properties of the humerus: implications for bioarchaeology

Thesis (M.S.F.S.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Bioarchaeologists work to reconstruct the past using skeletal remains inside a framework influenced by archaeological data. One area, into which bioarchaeologists have sought to provide insight, is the reconstruction of physical activities through skeletal indicators. These indicators of activity include looking at skeletal changes such as development of osteoarthritis, osteon remodeling, dental modifications, cross-sectional bone geometry (CSBG) and changes to muscle attachment sites, also known as entheseal changes. The study of entheseal changes has received much attention as researchers have hypothesized that a direct correlation between muscle use and entheseal size exists. Researchers sought to interpret specific movements such as spear-throwing or kayaking by examining the muscle attachment sites involved in those movements and analyzing the robusticity of the entheses. CSBG has also been used to analyze activity levels and interpret the degree of manual labor an individual was involved in. These analyses are based on the biomechanical interpretation of bone as structure that reacts to mechanical stress by increasing bone thickness. This research tested the hypothesis that changes to entheseal size in the humerus would correlate to changes in CSBG. Entheseal changes were analyzed using two methods, the Hawkey and Merbs (1995) and Mariotti et al. (2007) methods. Both methods were analyzed in terms of their ease of use and intraobserver error rates. The Mariotti et al. (2007) method of scoring entheseal changes was found to have more instances of a significant intraobserver error rate than the Hawkey and Merbs (1995) method despite the improved photographs and more detailed descriptions provided by the authors. Both entheseal scoring methods were used to analyze the correlation between entheseal changes and CSBG in the form of the polar moment of area (J) as standardized for size (J'). CSBG has been found to have stronger correlations with mechanical use and this research sought to identify relationships between entheseal development and J' in the humerus. Entheses scored using the Mariotti et al. (2007) method were more frequently found to have a significant correlation with CSBG, while only one enthesis scored using the Hawkey and Merbs (1995) method was found to have a significant correlation (p <.05) with CSBG. This implies that the method used greatly affects the identifiable correlations between entheseal changes and CSBG. Refined methods and more research are necessary before entheseal changes can be accurately used in activity reconstruction.2031-01-0