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

Bilateral aging asymmetry of the auricular surface


Department of Anthropology, University of Tennessee, Knoxville

Thursday All day, Plaza Level Add to calendar

Forensic anthropologists routinely estimate age-at-death of a deceased individual using the auricular surface of the os coxa. This presentation examines the dissimilarities between the left and the right auricular surfaces based on age indicator scores. It is accepted that there are occasional differences between the sides, and we hypothesize that these disparities are the exception rather than the rule. Therefore, the left and the right sides will generally be scored the same and differences, if present, will not be great.

In this study, 176 pairs of auricular surfaces from the William M. Bass Donated Collection housed at the University of Tennessee, Knoxville, were scored on 28 age indicator definitions from four different aging methods. Two additional variables were added, representing personal alternative interpretation of literature definitions. All observations were recorded by the first author.

The differences between the sides are analyzed using t-tests and simple statistical calculations, including range and percentage of dissimilarities. The results of these calculations paint a worrisome picture. While only two variables demonstrate a directional bias in age scores, 19 variables show asymmetry in greater than 30% of the cases. Indicators with a greater number of phases also have greater dissimilarities between the left and right sides.

This project illustrates that the left and right auricular surfaces are frequently at odds, and researchers should not automatically assume bilateral symmetry when aging skeletons. Anthropologists should avoid only using one side of the auricular surface unless necessary, and may need to establish new definitions of age indicators.

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