Bilateral Asymmetry of Long Bones in Bronze and Early Iron Age Pastoralists of the Altai

Abstract

The aim of the study is to explore patterns of directional asymmetry (DA) of long bones among the ancient pastoralists of the Russian Altai. Long bones of the upper and lower limbs and clavicles were measured bilaterally in two temporally diverse skeletal samples dating to the Middle Bronze Age and the Early Iron Age. Statistically significant sex and chronological differences were found in DA of the upper limb diaphyseal breadths, which are strongly influenced by mechanical factors during life. These results suggest that manual loadings were bilaterally symmetric in males, but not in females. Sexual dimorphism in the upper-limb-use asymmetry was greater in the later group than in the earlier group. Besides, the female subgroups exhibited strong DA in features evidencing biomechanical stress on the femur. Temporal differences in DA of the upper limb length are possibly due to changes in the level of environmental and/or genetic stress. * Supported by the Russian Foundation for Basic Research (Project No. 11-06-00360а) and the Russian Foundation for the Humanities (Project No. 12-01-00159).