Comparative analysis of facial morphology between Okinawa Islanders and mainland Japanese using three-dimensional images.

OBJECTIVES: Differences in facial height and breadth between Okinawa Islanders and mainland Japanese have been reported in previous craniometric and somatometric studies. This study using three-dimensional (3D) images aimed to identify more detailed characteristics of facial morphology in each population. METHODS: Using a hand-held 3D scanner, we obtained 60 facial surface images each from Okinawa Islanders and mainland Japanese. Twenty-one landmarks were plotted on a computer and 27 measurements of distances and angles between the landmarks were taken. Statistical analyses such as t test, principal component analysis (PCA), regression analysis, and discriminant analysis were performed to identify sex and regional differences, the patterns of facial features, factors explaining the facial patterns, and other features. RESULTS: Okinawa Islanders showed lower facial and nasal heights than mainland Japanese. Furthermore, we identified larger protrusions of the glabella and nasal root in Okinawa Islanders than in mainland Japanese. In the PCA, we observed components of facial shape patterns. These components mainly represented facial size (PC1), facial depth (PC2), the prominence of the glabella and nasal root (PC3), and facial breadth (PC4). We identified that the population difference is strongly associated with PC3. CONCLUSIONS: This study quantitatively identified differences in the facial morphology between Okinawa Islanders and mainland Japanese using 3D digital images, with special emphases on the differences in the nasal height and the prominence of the glabella and nasal root

ON THE QUESTION OF SIZE-INDEPENDENT SEX-SPECIFIC DIFFERENCES IN HUMAN LONG BONES

Forty six measurements of the humerus, radius, ulna, and femur of - depending on the bones 71-79 sexually known individuals from Holland were examined as to significant sex differences. With the exception of the depth of the fossa olecrani and the angle measurements significantly higher mean values were obtained for all measures in the male sample. Nevertheless, the ranges of variation overlap to such a large extent, that a faultless sex diagnosis is not possible even with the help of a discriminant analysis (estimation of the misclassification percentages for the population on which this analysis was based, is between 5 and 9%, depending on the bone). Regressions were performed on bone length as an indicator of size, to test whether the sexual differences are only due to size or to what extent they remain after ignoring the effect of size. The residual values of the measurements, for which a significant sex difference resulted from the original values, without exception lie higher on the average for the men than for the women. The sexual differences that are independent of size are significant for most measures, especially for indicators of robustness insofar as such a statement can be made in spite of the statistical problem that ensues from the fact that the residual scores are not independent of each other in the compared groups. With the same proviso it can be said that the discriminant analyses on account of the residuals do lead to significant discriminant functions, but that the misclassification percentages lie distinctly higher (at about 1/3) than when the size is included