Flatness of facial skeletons in Siberian and other circum-Pacific populations.

Thirty-four populations from Siberian and other circum-Pacific regions were compared in terms of facial flatness measurements of the cranium. While fundamentally having an extremely flat face, Siberian populations tend to be differentiated into two or three subgroups. On the other hand, other Mongoloid populations show greater variation in facial flatness. The less flat faces of the American Indians are almost equal to those of the Europeans. In Japan, the existence of two contrasting groups in terms of facial flatness have been found.