Secondary palate
A sagittal section of apig's (Sus sp.) snout showing the secondary palate with pronouncedpalatine raphe.
Details
Identifiers
Latin	Palatum secundarium, palatum definitivum
TE	palate_by_E5.4.1.1.4.0.5 E5.4.1.1.4.0.5
Anatomical terminology [edit on Wikidata]

Thesecondary palate is an anatomical structure that divides thenasal cavity from theoral cavity in manyvertebrates.

In humanembryology, it refers to that portion of thehard palate that is formed by the growth of the two palatine shelves medially and their mutual fusion in the midline. It forms the majority of the adult palate and meets theprimary palate at theincisive foramen.

Secondary palate development begins in the sixth week ofpregnancy and can lead tocleft palate when development goes awry.

There are three major mechanisms known to cause this failure:

1. Growth retardation — Palatal shelves do not grow enough to meet each other.
2. Mechanical obstruction — Improper mouth size, or abnormal anatomical structures in the embryonic mouth prevent fully grown shelves from meeting each other.
3. Midline epithelial dysfunction (MED)^[1] - The surface mucosa of embryonic shelves is impaired, which causes a failure of palatal fusion.

The secondary palate is thought to have a significant role in the development of somewarm-blooded animals. The separation of the mouth from the nasal cavity also allowed chewing and breathing to occur at the same time. Early creatures with secondary palates includecrocodilians (who are cold-blooded), andcynodonts and a few others among thetherapsids, known from the fossil record in the mid-Permian.Mammals inherited our hard palates from the cynodonts.

• Palate