Main long bones of limbs of the Jomon people--proportions in their lengths.

The proportional relationships among the lengths of main limb bones comprising the humerus, radius, tibia and femur of the Jomon people are examined by means of comparison with those of the Kofun and recent Japanese. The disto-proximal indices (the radio-humeral and tibiofemoral) of the Jomon are significantly greater than those of the comparison ages, but the humero-femoral index, as a intermembral, is significantly smaller. Logarithmic plots showing the relation between each two bones, indicate no significant age differences among the inclinations of regression lines corresponding to allometry coefficients. However, significant age differences among the levels of lines were found. According to previous studies, there may be two factors affecting the proportions among limb segments, one biomechanical and the other thermal. The adaptation to mode of life, such as hunting of quick moving animals, appears to be a more reasonable interpretation of the relatively long distal segments (high disto-proximal indices) of the Jomon people.