Growth of the mandible during pubescence.

Annual cephalometric radiographs of 67 children were used to analyze mandibular growth during pubescence. Annual increments were calculated for articulare-gonion (Ar-Go), articulare-gnathion (Ar-Gn) and gonion-gnathion (Go-Gn). Pubertal spurts were recorded for annual increments within two years of peak height velocity (PHV) that exceeded the immediately preceding increment by at least 1 mm (corrected for enlargement). Such spurts in mandibular dimensions are common but not universal. They were more common in the boys, but occurred about 1.5 years earlier in the girls. They tended to be larger in boys, although the mean increments in the two sexes were similar before and after the spurts. First pubertal spurts usually occur before PHV, but there was considerable variation in this relationship. Almost all first pubertal spurts occur after ulnar sesamoid ossification and before menarche. The variability of their timing was less in relation to PHV than in relation to skeletal age, menarche or ulnar sesamoid ossification. It can be desirable to determine whether a spurt has occurred in an individual patient. For this purpose, Greulich-Pyle skeletal age may be only slightly more meaningful than chronological age, and neither is sufficiently precise for many clinical applications.