Morphogenesis of the lateral nasal wall from 6 to 36 weeks.

This research describes the development of the lateral nasal wall, the description of which will allow a better comprehension of its anatomic complexity. One hundred embryos and fetuses from the sixth to thirty-sixth weeks of morphologic age were studied. The seventh week shows the first buds of the three turbinates. At the ninth week the precartilaginous nucleus of the inferior turbinate is observed. Likewise, at the tenth week the uncinate process appears, and the invagination of the epithelium begins the formation of the infundibulum and the maxillar sinus. At the fourteenth week the cartilaginous nasal capsule is present. The epithelium is invaginated, starting the formation of the ethmoid cells. During the seventeenth week of development the invagination of the mucus has invaded the maxillar bone, which constitutes the maxillar sinus. At the thirty-sixth week the lateral nasal wall is well developed. In 23 fetuses the supreme turbinate (fourth) was found. Although the length of the lower three turbinates increased progressively and proportionally in intrauterine life without differences between the sexes, the fourth remains invariably at an average length of 5 mm from the fourteenth to the thirty-sixth and was present in 65% of male fetuses.