Diving into dimensionality: Using multivariate methods to explore variation in intracortical bone area in a multi-scalar perspective

Life-course approaches in bioarchaeology rely on deep and meaningful understandings of skeletal heterochronicity—the differential rates and timing of growth, development, and maintenance processes. However, comparisons of different bone tissue regions proves challenging precisely because of the heterogeneous quantity and quality of cortical bone throughout the skeleton. We analyzed matched rib, metacarpal, and femoral cortical bone quantity indicators from a subset of individuals with excellent preservation in each of these three skeletal regions (n=70) from the medieval Italian site Pieve di Pava (10th-12th centuries AD). Previous results from this rural site suggest a complex underlying population substructure in cross-sectional properties with highly dispersed variation in most cross-sectional properties. Variation in relative cortical bone was assessed intraskeletally using standardized z-scores in order to normalize values across differing elements, alongside descriptive and multivariate statistics. Results show stochastic trends in the relationship between rib, metacarpal, and femora relative cortical bone quantity, but a general correspondence between femoral and metacarpal cortical bone values. However, on closer inspection we found that by examining the dimensionality in our dataset there were intersectional age- and sex-related trends that likely reflect confounding influences of the biocultural context, local mechanical environment, and genetics. We approach dimensionality in our dataset as a potential avenue for intervention and knowledge production, rather than a mere hindrance that needs to be reduced to understand central tendencies in the data. Our approach contextualizes these findings in terms of larger anthropological narratives of normalcy and disability studies.