Changes in the Craniofacial Skeleton During Postnatal Development
In the course of time much information on the postnatal changes occurring in the craniofacial skeleton has been collected. It is not particularly meaningful to deal here with data of limited significance for clinical philosophy and treatment despite their scientific interest.
It will suffice to indicate the changes in facial proportions, to proffer an overall picture of facial growth seen laterally and frontally, to mark out the regions of growth, and to present schematically the contributions of various growth regions to the vertical and sagittal development of the face.
5.2 Changes in proportion in the head
From birth to adulthood, the head not only becomes considerably larger; its proportions change remarkably. The brain and eyes are predominant in the head of a newborn. The neurocranium and orbits have reached, at birth, a much larger proportion of their adult dimensions than have the mandible and maxilla. The nose is partly contained between the eyes; the nasal floor lies in close proximity to the floor of the orbits. The morphology of the mandible and maxilla is determined mainly by the developing teeth which have been laid down within them (Figs. 5-1 and 5-2). The relative proportions of the parts of the head in the newborn, just as in its body as a whole, all reflect the priorities which are applied to the development of organs essential for the function of the organism prior to and directly after the birth. This applies, in particular, to the central nervous, circulatory, respiratory, and digestive systems. In the case of a newborn child, the requirements for the orofacial end of the alimentary canal are quite different from those later on. The presence of emerged teeth is not necessary; on the contrary, they are only a disturbance if present when breastfeeding is being employed.
Fig. 5-1 in the newborn (A and B). the part that contains the brain and eyes dominates the face. The structures lying beneath have not yet enlarged to the same degree. The differences in proportions, as compared with the fully grown version, are clearer when the head of the infant is just enlarged to adult diameters (C and D). In the adult (E and F), the middle and lower face have become much larger, with a relatively smaller increase in the upper face. The mandible and the tooth-bearing part of the maxilla have increased markedly in height.
Fig. 5-2 The changes in proportion between birth and maturity also become clearly apparent in the difference in relationship between the parts of the skull of an infant and that of an adult. In the skull of the newborn (A and B), the neurocranium markedly dominates the facial skeleton. The differences in proportion stand out well when an overall enlargement of the infant skull to adult size (C and D) is compared with a fully developed skull (E and F).
5.3 Development of the craniofacial skeleton
The development of the craniofacial skeleton has been investigated widely by means of standardized cephalometric radiographs of the head. As an illustration of the changes that have been found, two drawings (Figs. 5-3 and 5-4) are reproduced from the classic research of Broadbent and his coworkers.48 The changes in proportions are clearly apparent. Further, these drawings illustrate the fact that, just as in general growth, the craniofacial skeleton of boys continues growing over a longer period than that of girls. Moreover, the faces of boys become not only larger, but also of a different form than those of girls, since the chin, nose, and eyebrow ridges become more predominant and the incisors become more upright. Because the face continues to grow after the fo/>
Stay updated, free dental videos. Join our Telegram channel
VIDEdental - Online dental courses
