Sexual diagnosis of skeletons is of importance to physical and forensic anthropologists. The present study attempts to provide a basis from which one might choose a variable of a long bone that is most suitable in sexual assessments of skeletal material. A total of 47 variables of the humerus, radius, ulna, femur, and tibia of 64 recent-modern Japanese (32 male, 32 female) were investigated. The data were analyzed using the t-test and the stepwise discriminant analysis. The width of the articular surface of the distal humerus, the sagittal head diameter of the radius, the diaphyseal cross-section area or the articular breadth of the ulna, the bicondylar width or the transverse diameter of the lateral condyle of the femur, and the proximal epiphyseal breadth of the tibia were useful in sexual diagnosis of each of the long bones. Total accuracies of sex determination using these variables ranged from 91 to 95%. Among these measurements, sexual dimorphism tended to be greatest in the breadth diameters of the elbow and knee joints.

The Suchey-Brooks system, based on a collection of pubic bones from autopsied individuals in the United States with known ages at death, has gained wide acceptance as a method of estimating age from the morphology of the pubic symphyseal region. While some studies have suggested the influence of population variation on age estimations, there has so far been no study that applied the Suchey-Brooks system to Japanese skeletal materials. In this study, I evaluated the morphology of the pubic symphyseal region in a relatively large sample of recent Japanese skeletal material (n = 416) and derived mean ages and standard deviations for each of the six Suchey-Brooks phases. Results suggested that age estimation by this method is comparatively reliable in individuals up to 40 years of age but less reliable at higher ages. In all six pubic bone phases, differences between the mean ages of the Japanese and the Suchey-Brooks series were less than three years, demonstrating the applicability of the system to the recent Japanese.

Kinship analysis was performed on a Jomon double burial from the Usu-Moshiri site in Hokkaido, Japan, using odontometric data in conjunction with mitochondrial DNA data. Q-mode correlations with respect to tooth crown measurements indicated a low similarity between the two adult female skeletons found from this burial. Moreover, mitochondrial DNA analysis revealed that these individuals were not maternal relatives. Consequently, judging from both morphological and genetic evidence, these skeletons are more likely to have been unrelated rather than consanguineous. This is the first report that provides anthropological evidence for a lack of kinship of skeletons discovered from a Jomon double burial.

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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 between 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 measurements 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-gatherers (Amerindians). The loading conditions of the upper arms of Jomon people were also likely to be less asymmetric than in other populations, while differing considerably between sexes.