The
vestibular system, in most mammals, is the
sensory system that provides the leading contribution about the
sense of balance and
spatial orientation for the purpose of coordinating
movement with
balance. Together with the
cochlea, a part of the
auditory system, it constitutes the
labyrinth of the inner ear in most mammals, situated in the
vestibulum in the
inner ear (Figure 1). As movements consist of rotations and translations, the vestibular system comprises two components: the semicircular canal system, which indicate rotational movements; and the
otoliths, which indicate linear accelerations. The vestibular system sends signals primarily to the neural structures that control eye movements, and to the muscles that keep an animal upright. The projections to the former provide the anatomical basis of the
vestibulo-ocular reflex, which is required for clear vision; and the projections to the muscles that control posture are necessary to keep an animal upright.