Publication Date

Spring 2019

Degree Type


Degree Name

Master of Arts (MA)




Elizabeth Weiss


cross-sectional geometry, cross-sections, femora, geometric properties, medieval climatic anamoly, sex differences

Subject Areas

Physical anthropology; Biomechanics


This thesis aims to infer mobility patterns in the California prehistoric burial population of CA-ALA-329 (Ryan Mound) by conducting cross-sectional analysis on femoral bones. CA-ALA-329 is considered to be a burial ground used by precontact Ohlone natives in the San Francisco Bay Area. Glacial changes, pollen studies, and

tree-ring data show shifts in climate change occurred during the Late Phase 1 Period, causing warmer and drier temperatures throughout California. Seventy-seven femora were analyzed in this study including 26 femora representing the Middle Period and 51 representing the Late Phase 1 Period. Cross-sectional geometric formulae were applied to measurements collected at the subtrochanteric and midshaft regions on each femora. Two second moments of area, Ix and Iy, were calculated and ratios were used to determine where mechanical stress was placed as a result of stress and strain. Supporting data, such as polar moment of area, cortical area, and total area, were calculated, but not standardized for body size. Results of the study demonstrated significant changes in mobility over time. Anteroposterior robusticity in the subtrochanteric region decreased from the Middle Period to the Late Phase 1 Period in males, and increased in females. Anteroposterior robusticity in the midshaft region increased in males from the Middle Period to the Late Phase 1 Period, and decreased with females. These findings suggest a shift in mobility between the two time periods.