Annals of Human Biology vol:24 issue:2 pages:141-156
In their classical study on cranial suture closing, Todd and Lyon (1924-25) expressed their belief that suture closure proceeds according to some periodic pattern. Spectral analysis applied to their data corroborates the opinion of Todd and Lyon. Closure of the cranial sutures in humans is pervaded by a circaseptennian periodicity. Pulses of accelerated closure occur at intervals of about 7 years, and are separated by periods of relative quiescence.