The results are reported for an analysis of longitudinal sequences of lateral head X-rays of 50 Montreal girls, taken annually between the ages of 6 and 15 years. Mean size changes for distances within the cranial base, the maxilla and the mandible, as well as those outlining the facial polygon, are displayed on a common proportional scale based on mean sizes at 15 years old. Mean growth velocities are displayed on both a chronological age scale and on one relative to the individual age of peak growth velocity in stature. A distinct facial pattern of growth is established, In terms of the proportion of final size achieved during childhood, it is below the cranial pattern, but above the general skeletal one. This facial pattern shows a pubertal peak in growth, but one quantitatively less important than that for stature. The timing of the two peaks is closely aligned, although the evidence favours a slightly later development for the face. The mandibular ramus provided the sole exception to this common facial pattern, though some questions on maxillary growth remain open.

The major sexual dimorphisms in body size appear at puberty but, by then, 95% of the growth of the cranium is completed. As sexual dimorphism in the cranium is as great as for other parts of the body, this suggests that it must appear at an earlier age, and that cranium/body size ratios for the two sexes will vary during growth. Results from a longitudinal study of Montreal children are used to investigate this phenomenon. The effect is expressed quantitatively by proportional growth and growth velocity curves, based on the final size of boys, which show that the dimorphism indeed makes an early appearance. The data are also analyzed on an age scale relative to the ages of peak growth velocity in stature, derived from the individual growth curves. This shows that although there is a minor pubertal spurt in growth for the external cranial dimensions of boys, it contributes relatively little to the final dimorphism in cranial size. To summarize this aspect of growth, an index of cephalization is calculated: head length X head width/stature. Cross-sectional standards for the change of the mean index with age show a linear decline for boys and girls until puberty, with a constant difference between them. After puberty, the index becomes equal in the two sexes. Individual development curves for the index are however not linear.

Size and velocity growth curves of stature to represent skeletal growth, lean arm circumference to represent muscle growth, and the sum of three skinfolds to represent fat tissue changes, are presented for a longitudinal study of Montreal school-age chidren. Both a chronological age scale, and one relative to the individual ages of peak growth velocity in stature, are used. Intercorrelations between the various components are tabulated for age groups based on the two scales. The three skinfolds are also analyzed separately. The results show that such simple anthropometric measures can be usefully taken to represent the growth of different body components. Longitudinal analysis reveals that, whereas the relationship of muscular to statural growth in boys is purely maturational, it is not so for girls, and that the different skinfolds show complex sexual differences in growth during the pubertal period.