Sakamoto M K, Nakamura K, Handa J, Kihara T, Tanimura T
Department of Anatomy, Kinki University School of Medicine, Osaka, Japan.
Anat Rec. 1989 Mar;223(3):299-310. doi: 10.1002/ar.1092230309.
Morphological studies of secondary palate formation, with special reference to the development of rugae, were carried out on Jcl:ICR mouse embryos. Three rugae were observed on the anterior part of the future oral surface of the vertically developing palatal shelves in 13-day embryos. Rugae increased in number as the development of the palatal shelves proceeded, and five to six prominent rugae were observed in 14-day embryos just prior to shelf elevation. The folding of these five to six rugae progressed in conjunction with the formation of a sharp, valley-like groove at the base of the anterior two-fifths of the vertical palatal shelves. As palatal shelves elevated, the groove disappeared gradually, and, accordingly, the folding of rugae loosened. In the groove region, the superficial epithelial cells were roundish, while the basal ones were elongated. Such characteristic features were no longer observed when the disappearance of the groove was completed. Eight rugae were observed on the future hard palate of 14-day embryos with already completed palatal fusion. An additional ruga was frequently found in 15-day embryos, and the pattern then was almost the same as that of an adult. Epithelial thickening and condensation at the rugae region, as well as mesenchymal condensation under the epithelium of the rugae, were confirmed in embryos both before and after elevation of the palatal shelves. There is a possibility that these structural characteristics observed in the epithelial and mesenchymal cells of the rugae and groove regions may be related to palatal shelf elevation.
以腭皱襞的发育为特别参照，对Jcl:ICR小鼠胚胎进行了继发腭形成的形态学研究。在13天胚胎垂直发育的腭突未来口腔面的前部观察到三条腭皱襞。随着腭突的发育，腭皱襞数量增加，在14天胚胎中，就在腭突抬高之前观察到五到六条明显的腭皱襞。这五到六条腭皱襞的折叠与垂直腭突前部五分之二底部形成一条尖锐的、山谷状的沟同时进行。随着腭突抬高，沟逐渐消失，相应地，腭皱襞的折叠也变松弛。在沟区域，表层上皮细胞呈圆形，而基底细胞呈细长形。当沟完全消失后，这种特征就不再观察到。在腭融合已完成的14天胚胎的未来硬腭上观察到八条腭皱襞。在15天胚胎中经常发现一条额外的腭皱襞，此时的模式与成年时几乎相同。在腭突抬高前后的胚胎中均证实了腭皱襞区域的上皮增厚和凝聚，以及腭皱襞上皮下的间充质凝聚。腭皱襞和沟区域的上皮和间充质细胞中观察到的这些结构特征有可能与腭突抬高有关。
