The inner ear performs two major functions: hearing (via the cochlea) and body balancing/equilibrium (via the vestibular apparatus). The vestibular system includes: (1) semicircular canals — detect rotational acceleration of the head in three planes, and (2) utricle and saccule (otolith organs) — detect linear acceleration and static head position relative to gravity. Damage to the vestibular system causes vertigo, dizziness, and loss of balance.