Three-dimensional coordinates were obtained from Japanese skulls (male 41, female 37) with the aid of moire contourography, an optical device recently developed, which enables threedinensional measurement of the human body with contour lines on the surface. An origin and rectangular axes were set as follows: origin, a point on the median plane on which porion is projected perpendicularly: axis x, antero-posterior axis both on the median plane and the Frankfort plane: axis y, perpendicular to axis x, on the median plane: axis z, axis through both left and right porion. Eighteen landmarks were chosen and 44 coordinates were undertaken for basic statistics and principal component analysis. Mean values of coordinates in the male were larger than those in the female except for a few coordinates of the cranial vault.
Eleven principal components whose eigenvalues exceeded unity were obtained from principal axes analysis of the correlation matrix which was subsequently rotated by th Varimax criterion. Those were interpreted as cranial factors by the highest loadings as follows: F1, facial projection, F2, lateral fullness, F3, bregma, lambda, posterior and occipital bone, inferior, F4, size of the greater wing of the sphenoid bone, F5, occipital bone, posterior, F6, stephanion, superior, F7, anterior facial region, superior, etc. The result was compared with previous reports on factor analysis of the skull. First three components were coincided in general with those in previous studies in spite of the difference of materials and measuring methods.
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