A morphogenetic analysis of facial growth.

THIS study deals with a correlative morphologic and developmental analysis of the changes that take place during the postnatal growth of the face. It is based on information presented in previous studies concerned with growth and remodeling processes in the mandible and the nasomaxillary complex of the young human skull.lm3 Our present knowledge of postnatal facial growth is based largely on comparative phylogenetic correlations,3-* anthropometric studies,8-10 and serial cephalometric roentgenography. ‘l-l7 These various studies have provided a great deal of quantitative information concerning relative growth movements, angular relationships, and rates of growth in the various facial planes. It is well known that the neonatal face is characteristically small in relation to the more precocious cranium. The face undergoes a progressive postnatal enlargement, however, and its various proportions become markedly changed with age. The over-all vertical and horizontal dimensions of the face come to bypass, in differential rates of growth, the slowing postnatal enlargement of the cranial base and the calvarium. The purpose of the present report is to relate generalized patterns of facial growth with the corresponding patterns of structural remodeling which occur during the growth of the underlying facial bones. Continued increase in the size of the facial skeleton with age does not simply involve a generalized deposition of new bone on all outer surfaces. Rather, a complex series of remodeling changes takes place in all parts of the various facial bones as they increase in over-all size. These remodeling adjustments function in continuously maintaining the shape, the proportions, and the relationships of the various areas in each bone as the bone itself continues to grow. Detailed interpretations of these remodeling changes make possible an accurate analysis of the actual directions of growth in each individual region of each facial bone. It also makes possible an understanding of the mechanisms by which