The vestibule, which contains the oval window in its lateral wall, is the central part of the bony labyrinth (Fig. 8.129). It communicates anteriorly with the cochlea and posterosuperiorly with the semicircular canals.
A narrow canal (the vestibular aqueduct) leaves the vestibule, and passes through the temporal bone to open on the posterior surface of the petrous part of the temporal bone.