The purpose of this study is to investigate the relationship between skeletal maturity vs. the growth of body size of boys and girls aged 9 to 14 years in a longitudinal study. The skeletal maturity of hand was examined by means of X-rays. The subjects are 15 boys and 17 girls. Their skeletal maturity scores, 7 anthropometric measures and 6 indices based on the anthropometric measures were taken for six years from 1972 to 1978. The data obtained was analyzed; (1) as to the data covering from 9 to 14 years of age and (2) as to the data at each age level of 9 to 14 years of age. As the result of analysis (1), it was found that the mean growth curves of anthropometric measures are similar to the curve of the skeletal maturity score in both sexes. The coefficients of correlation between the skeletal maturity score and these anthropometric measures ranged from 75 to 90. The chronological age correlated with the skeletal maturity score with the coefficients, 89 for boys and, 83 for girls. Although these correlations are spurious in nature it was suggested that chronological age is the best sigle item of all the measurements to predict skeletal maturity. As to analysis (2), the correlations of chronological age (variance in birth date) with the skeletal maturity score were found to be very low within a group of same age. The correlations between the skeletal maturity score and anthropometric measures changed with age. Namely, the correlations between the skeletal maturity score and the linear measures in boys increased with age up to l4 years, while those in girls increased with age up to 11 years and thereafter decreased. The correlations between the skeletal maturity score and body bulk measures in boys increased with age up to 12 or 13 years and thereafter decreased. From these results it is inferred that skeletal maturity does not equally relate to the growth of all body sizes and its contributing rates to the growth of body sizes varied with age and for sex.
