Fourth ventricle

Ventricle (a normal cavity) of the rhombencephalon of the brain; a cavity of irregular tent-like shape extending from the obex frontward to its communication with the sylvian aqueduct, enclosed between the cerebellum and the rhombencephalic tegmentum. The ventricle of the brain which lies between the cerebellum and the brainstem. It expresses CSF into the subarachnoid space via the two lateral foramina of Luschka and the single medial foramen of Magendie.