Pubertal spurts in cranial base and mandible. Comparisons within individuals

Serial data from cephalometric radiographs were analyzed for 34 boys and 33 girls who had cephalometric radiographs annually near each birthday from at least age 7 through 18 years. Spurts were defined for this study as increases between successive cranial base increments that exceeded 0.75mm/year in boys or 0.5mm/year in girls. The corresponding criterion for the mandible was 1.0mm/year in either sex. Pubescence was defined as the 4- year period spanning 2 years before and after peak height velocity. Spurts during pubescence were common, tending to occur about 1.6yr earlier in girls than boys. The mean increments at first pubertal spurt (FPS) and the mean sizes of FPS were about 25% to 33% greater in the boys than in the girls. The rate of growth during the year before FPS tended to be greater in the girls, while in the year after FPS it tended to be greater in the boys. The timing of FPS in either cranial base of mandible was not closely related to the onset of ossification in the ulnar sesamoid, the age at peak height velocity, or age at menarche. FPS generally occurred after the onset of ossification of the ulnar sesamoid, but before peak height velocity and menarche. There was no evidence of difference between craniofacial EPS in children who passed rapidly or slowly through pubescence, nor was any difference noted between the size of pubertal spurts in tall or short boys. larger total increments after peak height velocity were found in the short boys. Significant correlations were identified between the cranial base and the mandible in the timing but not in the magnitude of FPS. The children were approximately equally divided between those in whom cranial base spurts occurred first, those in whom mandibular spurts were first, and those in whom FPS occurred in both areas within the same annual interval.