Prenatal Development of the Rat Palate

Abstract

This study was undertaken to provide information on the prenatal formation of the rat palate. Emphasis was placed on the elevation of the palatal shelves, fate of midpalatal epithelial lamina, and the formation of the bony palate. Pregnant female rats of the Holtzman strain were sacrificed 16 to 21 days after conception. The fetuses were removed and prepared for nitrocellulose embedding in the routine manner. The palatal shelves of the 16-day fetuses were directed ventrally on either side of the tongue. Elevation and fusion of the palatal shelves was completed by the 17th day, and degeneration of the midpalatal epithelial lamina began soon after fusion. A few epithelial remanents were observed in only 1 fetus at 18 days, and none was found in 19-day fetuses. Intramembraneous osteogenesis began at the lateral surfaces of the palate at the 17th day and reached the midpalatal region by the 21st day.