In humans, the development of the face and its features such as the nose and palate occurs in the embryonic stage of fetal development. The molecular events that set in motion these developments occur within the first few weeks following fertilization of an egg with a sperm. By the end of the sixth week there is visual evidence of development, and by the end of the eighth week of fetal development, the face is structurally recognizable as that of a human.

During these critical weeks of fetal development, the head region of the embryo assumes a pronounced bulb-like shape. A series of pouches, branchial arches, project forward from this protuberance. The head and face arise from the joining together of cells that originate from one of the brachial arches and other so-called "prominances" or "primordia", such as the...