The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Regional Variation in Osteon Size at the Femoral Midshaft

TIMOTHY P. GOCHA1,2 and AMANDA M. AGNEW1,2.

1Skeletal Biology Research Laboratory, Division of Anatomy, The Ohio State University, 2Department of Anthropology, The Ohio State University

March 27, 2015 , Archview Ballroom Add to calendar

During the last half century, various researchers have demonstrated the size of secondary osteons to be a useful variable in addressing many questions of anthropological import. Osteon size can help distinguish bone fragments as human or non-human, demonstrates a significant relationship with human chronological age, and has been suggested useful in interpreting biomechanical strains on bone. However, when measuring osteons at the femoral midshaft, little attention has been paid to potential regional variation in osteon size. Recent research in our lab demonstrates there is significant spatial heterogenetity in cortical remodeling rates and density at the femoral midshaft. This research sought to examine if this regional variation extends to osteon area (On.Ar) as well.

Ten femoral midshafts from modern male cadavers (aged 29–97) were imaged and digitally subdivided into anterolateral, anteromedial, posteromedial, and posterolateral quadrants. Within the periosteal third of each quadrant, 100 intact secondary osteons were measured using geographical information systems (ArcGIS 10.1) software. An analysis of covariance (ANCOVA) was used to examine On.Ar by quadrant, controlling for age related effects. The ANCOVA demonstrated mean On.Ar is significantly different between quadrants (p<0.001). The anterolateral quadrant of the femur, which has the highest remodeling rate, consistently has the smallest mean On.Ar (~35,000µm2). The mean On.Ar for each of the anteromedial, posteromedial, and posterolateral quadrants was significantly larger than in the anterolateral quadrant, with values consistently between ~42–44,000µm2. Based upon these results, it is suggested that future research should employ sampling strategies that account for regional variation in osteon size.