- Feb 12, 2016
The Infraglabellar notch
The infraglabellar notch is deepest in Australian aborigines and Melanesians, and smoothest in sub-Saharan Africans. “A few populations originally derived from eastern Asia, such as the Nicobarese and the Easter Island samples, and to a lesser extent the Eskimo and the Fuegian-Patagonian samples, show deep infraglabellar notches
Alveolar index (prognathism; the extent of jaw projection)
The greatest contrast when it comes to jaw protrusion is between Europeans on the one hand and sub-Saharan Africans, Australian aborigines and Melanesians on the other hand
Sagittal frontal index
The sagittal frontal index is a measure of how flattened or rounded the forehead (frontal bone) is in the sagittal plane or profile view, and is calculated by dividing the sagittal frontal chord by the sagittal frontal arc
Among the 17 regional samples, the Australian samples have, on average, flat frontal bones. However, the Southeast Asian Nicobarese sample shows the flattest frontals, followed by three samples from sub-Saharan Africa (the Congo, the Tanzania, and the Khoi-San samples). It should be noted that the South Indian Dravidian sample together with the Veddah and the northwest Indian samples have flatter frontal bones than many of the Near East, north African, and European samples. The groups with the opposite condition, or rounded frontal bones, are, on average, New World samples except for the Eskimo sample, and the northeast Asian samples.
Frontal index (fronto-orbital flatness)
This index is obtained by dividing the nasion subtense by the inner biorbital breadth
The northeast Asian samples and to a lesser degree the east Asian samples, except for the Ainu, show the smallest mean values, i.e., the flattest faces in the fronto-orbital portion. The degree of fronto-orbital flatness is weaker in the Australian/Melanesian samples than in the east/northeast Asian samples. The series from southeast Asia exhibits intermediate values, indicating a roughly clinal variation. With the possible exception of the Eskimo sample, the New World samples show a less flattened fronto-orbital region, comparable to the Australian and the Melanesian samples. In the western hemisphere of the Old World, no significant difference in the degree of fronto-orbital flatness can be detected, thereby showing projecting faces in these populations
Simotic index (flatness of nasal bones)
The sub-Saharan African samples have very flat nasals, especially the Khoi-San sample. Of all the samples examined, the European samples show the highest nasals, followed by the Indian subcontinent samples, the Oceanian samples, and, very significantly, the New World samples and the Ainu sample from Japan. As is well known, the nasal form of Eskimos and, to a lesser extent, Chukchis shows what has been referred to as ‘‘pinched nasalia,’’ a condition which is characterized by a narrow nasal chord and high subtense.
Zygomaxillary index (mid-facial flatness)
As in the case of the frontal index, the northeast Asian samples and to a lesser degree the east Asian samples show the smallest mean values of the zygomaxillary index, indicating the flattest faces in the mid-facial region. The Australian and the Melanesian samples exhibit, on average, a high value of the zygomaxillary index, followed by the samples from the western hemisphere of the Old World.