Antrum

In Biology, "Antrum" is a general term for a cavity or chamber which may have specific meaning in reference to certain organs or sites in the body.

Examples include
 * antrum cardiacum - a dilation that occurs in the esophagus near the stomach (forestomach)
 * mastoid antrum - Synonym: antrum mastoideum, tympanic antrum, Valsalva's antrum
 * pyloric antrum - the initial portion of the pyloric part of the stomach
 * antrum follicularum - the cavity in the epithelium that envelops the oocyte

Antrum