Bilateral Asymmetry of the Humerus in Jomon People and Modern Japanese

抄録

In the present study, I examined the bilateral asymmetries of several morphological characters of the humerus of 63 modern Japanese (male 46, female 17) and 40 Jomon people (male 20, female 20) with the aim of distinguishing be-tween metric features that are strongly affected by mechanical loading and those that are not, and to discuss the loading conditions of the upper arms of Jomon people.The results were that the bilateral asymmetries of humeral length and all other mea-surements except for proximal epiphyseal breadth did not correlate significantly with asymmetries of diaphyseal geometric properties.Since the longitudinal growth of a long bone stops when its epiphyses are fused with the metaphyses while corticla remodelling goes on for life, the present results can be interpreted as follows: 1) Bilateral asymmetries in the longitudinal direction is likely to reflect the cumulative loading conditions to around an age of 20 years, and 2) bilateral asymmetries in the tranverse direction reflects loading conditions relatively close to the time of death.Regarding the loading conditions inferred for the upper arms of Jomon people, it is suggested that they were stronger than in modern Japanese and some hunter-gather-ers (Amerindians).The loading conditions of the upper arms of Jomon people were also likely to be less asymmetric than in other populations, while differing consid-erably between sexes.