Supraorbital foramen and hypoglossal canal bridging : The two most suggestive nonmetric cranial traits in discriminating major racial groupings of man.

Abstract

Anatomical and developmental characteristics of the supraorbital foramen and hypoglossal canal bridging were reviewed. Scoring of the foramen on the supraorbital margin opening to the orbital cavity as the supraorbital foramen was recommended in order to simplify the criterion for trait judgement. The two traits were classified in the hyperostotic category on the basis of their developmental nature. Incidence data of the two traits were compared among 38 Mongoloid, 37 Caucasoid, 4 Negroid, and 13 Oce-anian samples. It was confirmed that the occurrence of supraorbital foramen is more frequent in Mongoloids than in Caucasoids, Australian Aborigines, and Negroids, while that of hypoglossal canal bridging is less frequent in Australian Aborigines, Negroids, and Asian Mongoloids than in Caucasoids and North American Mongoloids. The combination of incidences of the two variant traits appeared to be effective in discriminating the major racial varieties of man. Incidence data for Japanese pre-and protohistoric samples indicated that the Yayoi series of Doigahama type as well as those of the Kof un have a close resemblance to the modern Japanese samples and little resemblance to the Jomon series. From these results, it was inferred that the Jomon genetic contribution to the modern Japanese is slight and the modern Japanese consist mainly of the descendants of neo-Mongoloid immigrants from the Asian continent.