The vestibule is the central part of the bony labyrinth in the inner ear, and is situated medial to the eardrum, behind the cochlea, and in front of the three semicircular canals.

On its medial wall, at the forepart, is a small circular depression, the recessus sphæricus, which is perforated, at its anterior and inferior part, by several minute holes (macula cribrosa media) for the passage of filaments of the acoustic nerve to the saccule; and behind this depression is an oblique ridge, the crista vestibuli, the anterior end of which is named the pyramid of the vestibule.

This ridge bifurcates below to enclose a small depression, the fossa cochlearis, which is perforated by a number of holes for the passage of filaments of the acoustic nerve which supply the vestibular end of the cochlear duct.

The orifice of the vestibular aqueduct is the hind part of the medial wall; it extends to the posterior surface of the petrous portion of the temporal bone.

It transmits a small vein and contains a tubular prolongation of the membranous labyrinth, the endolymphatic duct, which ends in a cul-de-sac between the layers of the dura mater within the cranial cavity.