The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Estimation of femoral second moments of area from shaft's external dimensions (AP and ML diameters)


Department of Anthropology, Tulane University, Department of Anthropological and Historical Sciences, University of West Bohemia

Thursday All day, Plaza Level Add to calendar

In recent years, bioarcheology witnessed an increase in interpreting past human behavior through biomechanical analyses. There are several methods either for direct derivation of cross-sectional properties (CT) or their estimation (latex cast, ellipse model methods etc.). However, these could be either laborious (casting) or not readily available (CT), especially for larger samples. Pearson et al. (2006) came up with regression equations for estimating the Polar moment of area (J) at midshafts of several long bones from their AP and ML diameters. Here, we take up on this by providing estimation equations for J at several femoral cross-sectional locations. Multiple locations have been chosen due to our understanding that the femoral midshaft may not be the best location for behavioral inferences. We obtained femoral CT scans for 206 individuals from Early Medieval to Modern period of the Central Europe (Czech Republic). AP and ML diameters were recorded from the CT slices in the BoneJ plugin for ImageJ in all individuals and for a portion (n=71), the two measurements were also gathered manually with digital caliper for error comparison between manual and computer derived data. Multiple regression analyses were performed on raw and log transformed data. Estimation equations will be provided for the interval from 20 to 80 % of femoral biomechanical length in 5 % steps (13 equations). Here, we provide an equation for the midshaft in raw (J = -120859 + 3121*AP + 2929*ML; ±3648.7; R2=0.94) and natural log transformed data (LnJ = -1.99417 + 1.9126*LnAP + 1,91231*LnML; ±0.06953, R2=0.96).

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