Comparative craniofacial variation in Navajo Indians and North American Caucasians

Landmarks digitized from lateral cephalometric radiographs of 107 Navajo Indians between 10 and 12 years of age were analyzed to determine coefficients of variation or standard deviations for 38 cephalometric measurements. These values were compared with the same measures of variation for identical measurements on North American whites derived from the Michigan and Philadelphia Growth Studies. For the majority of variables, there were no differences between groups. Variation for the genetically and environmentally isolated Navajo Indians was the same as that of the highly diverse Caucasian samples. However, measurements of upper, lower, and total anterior facial height (N-ANS, ANS-Me, and N-Me, respectively) indicate that these features are substantially less variable in Navajo Indians relative to the Michigan and Philadelphia populations.