A system of fluid passages in the inner ear, including both the cochlea, which is part of the auditory system, and the vestibular system, which provides the sense of balance. The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The bony labyrinth is lined with the membranous labyrinth. There is a layer of perilymph between them. The three parts of the bony labyrinth are the vestibule of the ear, the semicircular canals, and the cochlea. The vestibular system is the region of the inner ear where the semicircular canals converge, close to the cochlea (the hearing organ). The vestibular system works with the visual system to keep objects in focus when the head is moving. Joint and muscle receptors also are important in maintaining balance. The brain receives, interprets, and processes the information from these systems that control our balance. [WP,unvetted]. [ http://en.wikipedia.org/wiki/Bony_labyrinth ]