Lateral recess

Lateral recess of fourth ventricle, is a paired extension of the fourth ventricle of the brain that projects laterally towards the pontomedullary junction, reaching the lateral border of the brainstem. At this point, the cavity of the fourth ventricle attains its maximum width.
Each lateral recess opens into a lateral aperture that opens into the subarachnoid space at the cerebellopontine angle. This aperture provides one of the major pathways through which cerebrospinal fluid exits the ventricular system into the subarachnoid space.
Within the area of the lateral recess lie the vestibular area and the cochlear nuclei, which form part of the vestibulocochlear nerve. The medullary striae of the fourth ventricle traverse the floor of the ventricle near this area.