The stomodeum, also called stomatodeum or stomatodaeum, is a depression between the brain and the pericardium in an embryo, and is the precursor to the mouth and the anterior lobe of the pituitary gland.

With the further expansion of the brain, and the forward bulging of the pericardium, the buccopharyngeal membrane is depressed between these two prominences.

No trace of the membrane is found in the adult; and the communication just mentioned must not be confused with the permanent isthmus faucium.

The lips, teeth, and gums are formed from the walls of the stomodeum, but the tongue is developed in the floor of the pharynx.

This article incorporates text in the public domain from page 1101 of the 20th edition of Gray's Anatomy (1918)