GROWTH OF THE PALATE IN THE HUMAN FETUS

¹ Department of Anatomy, College of Dentistry, New York University and Department of Histology, School of Medicine, American University of Beirut, Syria

The development of the palate in the fetus is related to a series of growth processes. The most characteristic feature of palate growth in early fetal life, is a preponderance of dolichouranic palates. The fetal palate is established as a dolichouranic type, from which, by a series of organized linear growth changes, the palate types seen in postnatal life are developed: the mesuranic, brachyuranic and hyperbrachyuranic forms. Within each palate type general variability is observed in the anterior arch curvature.

Growth in length of the palate proceeds steadily throughout fetal life, but more rapidly in the posterior than in the anterior and middle portions, allowing for increase in the posterior alveolar arch to accommodate the permanent teeth. Increase in breadth is linear throughout fetal life, and proceeds more rapidly than increase in length. This more rapid growth in breadth contributes to the alteration of palate form that appears prominently in later fetal and in postnatal life. Increase in height of the palate is also linear. A rather flat, unarched roof is observed in the early fetal period. The increase in height of the palate which converts it into the arched form is related to differences in the dimensional growths. Linear increase in length and breadth of the maxilla also occurs during fetal life, and, as in the palate, the increase is more rapid in breadth than in length. This is dependent largely on the rate of growth of palate and alveolar arch. The palate and maxilla exhibit parallel increases in rate of growth in length, but the maxilla grows more rapidly in breadth than the palate, perhaps directly influenced by adaptation of the alveolar arch to the developing teeth.