1Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, 2School of Archaeology and Anthropology, Australian National University
April 21, 2017 , Acadia
It has been recently suggested that the circularity of secondary osteons (On.Cr) may be useful in determining biomechanical loading history from long bone microstructure. However, the variability of On.Cr in adult human cortical bone requires investigation to inform future methods. We studied femora from 15 medieval adult males to test whether On.Cr variation occurs with bone size and anatomical region.
Sex and age-at-death were determined following standard methods. Classic macro-morphometric and cortical measurements were collected to group the femora into gracile (n = 8) and robust (n = 7) categories. Bone microstructure was examined in thin sections removed from the anterior and posterior midshaft. Using ImageJ, On.Cr index values were measured for an average of 30 osteons per thin section.
Osteons were significantly more circular in the gracile than in the robust femora when both anatomical regions were pooled (p = .000), as well as when comparing anterior (p = .001) and posterior (p = .001) osteons. A subsequent related-samples analysis revealed that anterior osteons were significantly more circular than those from the posterior region in the gracile category only (p = .028).
Results indicate that two-dimensional cross-sectional shape of secondary osteons varies with bone size. This may be in part related to mechanical strain differences associated with skeletal remodeling and modeling. Our analysis also suggests that On.Cr may be affected by sampling location as a result of localized remodeling in adult cortex.