One of the set of long, stiff projections, several micrometres long, from the apical surface of hair cells in the inner ear. They resemble microvilli and are supported by bundled microfilaments: their role is probably to restrict the movement of the sensory cilium, which has an axoneme and is sensitive to bending. Morphologically similar projections are also found on the apical surface of the pseudostratified epithelium in the epididymal duct. Often misleadingly called a stereocilium even though there is no axoneme.
Subjects: Medicine and Health.