“BPPV occurs when tiny calcium crystals called otoconia come loose from their normal location on the utricle, a sensory organ in the inner ear.

If the crystals become detached, they can flow freely in the fluid-filled spaces of the inner ear, including the semicircular canals (SCC) that sense the rotation of the head. Otoconia will occasionally drift into one of the SCCs, usually the posterior SCC given its orientation relative to gravity at the lowest part of the inner ear.”

Johns Hopkins Medicine