Third Ventricle

**Semantic type:** Body Space or Junction

**Definition:** A centrally placed component of the ventricular system of the brain located in the diencephalon. Cerebrospinal fluid from the lateral ventricles flows into the third ventricle via the foramina of Monroe and exits the third ventricle via the aqueduct of Sylvius. The thalamus and hypothalamus border the lateral walls of the third ventricle.

**Synonyms:** - BRAIN, THIRD VENTRICLE - Third Cerebral Ventricle - Third Ventricle of Brain - Ventricle, Third