An
otolith (οτο-,
oto-, ear + λιθος,
lithos, a stone), also called
statoconium or
otoconium, is a structure in the
saccule or
utricle of the
inner ear, specifically in the
vestibular labyrinth of vertebrates. They have been identified in both extinct and extant vertebrates. The saccule and utricle, in turn, together make the
otolith organs. They are sensitive to
gravity and linear
acceleration. Because of their orientation in the head, the utricle is sensitive to a change in horizontal movement, and the saccule gives information about vertical acceleration (such as when in an
elevator).