My dissertation investigates how biology and culture impact human skeletal morphology. The human skeleton offers insights into an individual's lived experience, which can be quantified as morphological changes brought about by intrinsic (e.g., hormones, genetics, nutrition) and extrinsic (e.g., climate, socioeconomic impacts, political decisions) forces acting on aspects of human variability. The result is patterned (and thus predictable) skeletal variation. Forensic anthropologists utilize this patterned morphological variation to estimate the components of the biological profile (i.e., age, sex, stature, and population affinity). In more general terms, this patterned variability results from the inherently plastic nature of the human body, which responds to external forces but only in a limited number of ways. The malleability of the human skeleton underscores the complexity of this phenotypic expression.This research considers the potential contributory forces of 11 postcranial macromorphoscopic (MMS) traits, investigated at various stages of growth and development throughout childhood and well into adulthood, and within a number of quantifiable biocultural contexts that may account for skeletal differences. Previously, the timing and causes of postcranial variation were poorly understood. However, I identify potential factors influencing morphological change and assess the biological (intrinsic) and cultural (extrinsic) factors influencing and potentially generating postcranial skeletal morphology across the life course. This research offers a novel perspective beyond the skull, using under-researched, but quantifiable variations in the cervical vertebrae, scapulae, sternum, humeri, femora, patellae, and calcanei. Focusing on implications for forensic anthropology, while accounting for biological-cultural interactions, this study investigates postcranial morphology within four theoretical frameworks: 1) human variation and population history, 2) secular change, 3) growth and development, and 4) biocultural evolution. Employing these frameworks, I explore the utility of cranial and postcranial MMS traits—in tandem—in machine learning models to estimate population affinity and generate likelihood estimates for group membership as a measure of biological distance. Next, I focus on spinous process morphologies in cervical vertebrae to identify and quantify levels of secular change. I then consider growth rates and timing, particularly relative to developmental processes and puberty, using a model designed to capture, measure, and quantify the age-of-appearance/age-of-stability of these morphological variants. Finally, I model sociocultural impacts—social race, socioeconomic status, and education— on postcranial MMS traits to determine whether these factors influence skeletal morphology. These efforts are each designed to shed light on the nuanced relationship between biology, culture, and social dynamics within the context of forensic anthropology.
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