Abstract:
We have morphologically investigated 49 histological sections of the human embryos. We have found out that at the beginning of the embryonic period nasal placodes are developed, and in the middle of the period nasal fossae are formed. Nasal fossae are limited by the horseshoe-shaped protuberances which are thickened in the shape of rolls, that is the primary stage of the front and side nasal outgrowths development. Further there happens an intensive development of the nasal fossae and adjacent structures, as a result of which they change into nasal chambers. At the end of the embryonic period there happens a nasal chambers break in the primary oral cavity with the formation of the primary choanae. Due to the middle nasal outgrowth junction a nasal septum is formed. Primary nasal cavity and primary oral cavity are separated by a primary palate.
