Area Postrema

**Definition:** A small, rounded eminence on each side of the FOURTH VENTRICLE, which receives nerve fibers from the SOLITARY NUCLEUS; SPINAL CORD; and adjacent areas of the MEDULLA OBLONGATA. The area postrema lies outside the BLOOD-BRAIN BARRIER and its functions include acting as an emetic chemoreceptor.

**Tree numbers:** - A06.688.178.500 - A08.186.211.132.810.591.500.286 - A08.713.049.500

**Synonyms:** - Chemoreceptor Trigger Zone