1Department of Forensic Medicine, Medical University of Vienna, Austria, 2Center of Anatomy and Cell Biology, Medical University of Vienna, Austria, 3City Archaeology, Municipal Department of Culture and Education St. Pölten, Austria
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Several osteometric approaches to estimate physical side dominance have been reported recently. However, the reliability of these methods is far from satisfactory for forensic applications. Here, we report a very significant side-to-side difference of the humeri observed radiographically in an individual with unilateral hand amputation, and extend the study to a more comprehensive population of untraumatized individuals.
Specifically, the left-hand amputated male and additional 20 individuals (9 females, 11 males; 16 adults, 4 matures) recovered from the same medieval graveyard, were subjected both to osteometric measurements and single-shot digital x-ray screening of the bilateral bones. The region of interest (ROI) for measurement of mean gray-scale values, correlating with the mineral density, was defined distal from the midpoint of the humeri, sized to: ROIwidth=250Px; ROIheight=(Humerusmaximum length/366)x200Px. Standardized bilateral asymmetry (SBA) was calculated by the generalized formula: SBA=(Rvalue-Lvalue)x100/((Rvalue+Lvalue)/2). Accordingly, positive SBA values indicate right-handed (RH) and negative ones left-handed (LH) individuals.
Other than in the osteometric measurements, radiographically detected bone mineral density differences were highly significant (SBAmean=16.3±5.1; p<0.001), allowing reliable prediction of handedness (RH =19, LH=1). No significant differences were observed between females (SBAmean=17.4±5.5) and males (SBAmean=15.4±4.8), nor between adults (SBAmean=16.8±5.1) and matures (SBAmean=14.2±4.9). The most significant difference in bone mineral density (SBA=43.6) occurred, unsurprisingly, with the amputated individual.
Further studies with an larger population of individuals with known handedness are currently in progress to substantiate the value of the suggested X-ray screening approach for the estimation of handedness, and to establish its potential for forensic anthropology casework.