Cephalic index of Japanese children with normal brain development.

The cephalic index is a method of assessing skull morphology in craniosynostosis. There are known racial differences; however, there are few reports on this index in Japan. In this study, we investigated the cephalic indices of Japanese children with normal brain development using axial slice computed tomography. Children presented to our institution because of head injuries but received no particular diagnosis. One hundred four children with normal brain development (62 males and 42 females) were divided into 7 age categories, namely, 4 categories for those younger than 1 year and 3 categories for those between 1 and 3 years. The cephalic index was calculated according to the following equation: (cephalic width/cephalic length) × 100. The cephalic indices by age groups were as follows: 86.7, 0 to 3 months (n = 21); 87.5, 4 to 6 months (n = 9); 89.2, 7 to 9 months (n = 16); 86.3, 10 to 12 months (n = 9); 85.9, 1 year (n = 25); 86.3, 2 years (n = 15); and 83.7, 3 years (n = 9). In this study, the cephalic indices of Japanese children with normal brain development tended to be more brachycephalic than those of white children, as reported by Haas and Waitzman. Thus, we formulated the classification of current cephalic indices of children with normal brain development in Japan.