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

Sexual dimorphism of the bony labyrinth in modern humans: a pilot study


1Paleoanthropology, Dept. of Early Prehistory and Quaternary Ecology, Senckenberg Center for Human Evolution and Paleoecology, Eberhard Karls University of Tuebingen, 2Forensic Anthropology, School of History, Classics and Archaeology, University of Edinburgh

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Sex estimation in forensic or archaeological settings is often difficult due to the commonly fragmented state of human remains. We aim to assess the feasibility of estimating sex by metric analysis of 3D reconstructions of the bony labyrinth of the inner ear, a structure that completes growth before birth and preserves well under harsh taphonomic conditions.

A sample of 52 cranial Computer Tomography scans from a Cretan known-sex population was used to create 3D reconstructions of the bony labyrinths using the AMIRA software package. Measurements of the height and width of the semicircular canals and cochlea were taken following Spoor (1993). Indices of the height divided by width were also calculated to test for differences in shape. Subsequently statistical analysis was conducted with SPSS 14.

All measurements except the lateral canal width, right cochlea width, and the height and width of the left cochlea demonstrated significant dimorphism. Bilateral asymmetry was also tested and found to exist in the cochlea and semicircular canals. Discriminant functions were created to sex unknown individuals. Univariate equations yielded a maximum cross-validated accuracy of 76% and multivariate analysis improved accuracy to almost 79%.

Thus developing discriminant function equations for sex estimation this structure would allow for the same standards to be applied to individuals of any age. Although sample size is small, this 3-D reconstruction technique appears to have great potential for the sexing of fragmentary remains and individuals of uncertain age.

This research was supported by the Institute for Aegean Prehistory

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