The expression of asymmetry in hand bones from the medieval cemetery at Écija, Spain

The unique nature of ‘handedness’ in modern humans poses questions about the development of this trait in both extinct hominid species and archaeological populations. An examination of the expression of hand preference in skeletal material is required to answer such questions. The main focus of previous research on asymmetry and hand preference has been on the bones of the upper limb, rather than those of the hand. This study addresses this issue by exploring the expression of asymmetry in the metacarpals and phalanges in 65 adult skeletons from the Medieval Muslim cemetery in Écija, Spain. From comparisons of metric properties of the bones and muscle marker development, varying patterns of asymmetry distribution were found. Sex was found to have a highly significant effect on metric properties, but not on asymmetry scores or muscle development. Age was not found to be significant in any of the analyses. These results suggest that the expression of hand preference varies throughout the hand, and is influenced by the method with which it is assessed. The bones of the hand have an important contribution to make to handedness research, as long as care is paid to associated methodological issue