Interrelationships of skeletal maturation, sexual development and somatic growth in man

Data on the age of attainment of various stages of puberty in some 70 girls and 100 boys of the longitudinal Harpenden Growth Study have been used to study the relation between skeletal age and sexual maturation. The variation in the skeletal ages of girls when they attained breast stages 2 and 5, pubic hair stage 3, the peak of adolescent growth spurt and 95% of their adult height was compared with the corresponding variation in their chronological ages. Only at menarche, 95% mature height and pubic hair stage 3 was skeletal age significantly less variable than chronological age. In boys at 95% of their mature height, skeletal age was significantly less variable than chronological age but no significant differences were found at genital stages 2 or 5, pubic hair stage 3, or the peak of the adolescent growth spurt. There was a positive correlation between skeletal and chronological age on reaching each stage of puberty in both sexes. The data suggest that the ossification of the skeleton in prepubertal children is independent of those maturational processes which lead to the development of the secondary sex characters. The role of skeletal age in predicting adult height is apparently not dependent upon a relationship between skeletal age and the attainment of peak height velocity but upon a more direct relationship with the percentage of growth which has been completed.