A cross-sectional study of human craniofacial growth.

It is generally accepted that different cranial regions do not follow the same growth pattern. In this study, size changes of the functional cranial components (FCCs) in 228 human skulls of age at death between 0 and 20 years were evaluated. The skull is considered as divided into anteroneural, midneural, posteroneural, otic, optic, respiratory, masticatory and alveolar FCCs. Age-related changes of FCCs were assessed by fitting curves with the smoothing spline method, and quantifying the proportional increments at different stages. All FCCs show a high growth rate in the first 3-5 years of life. Two groups of growth trajectories can be distinguished. The anteroneural, midneural, posteroneural and optic FCCs are more advanced at all stages; they show a high growth rate before 3-5-years-old and a low rate later. This difference is less pronounced in the group comprising the respiratory, masticatory and otic FCCs. The alveolar FCC shows an independent pattern. The similarities among FCCs of the two groups are best explained by their common embryological origin. In contrast, the participation in a common function cannot be associated with the co-ordinated variation, given that the masticatory and alveolar FCCs show independent trajectories.