vestibula

Vestibula is the Latin plural form of vestibulum, and in anatomy the term denotes a vestibule, a hollow or entry chamber that marks a transition between regions of a structure. In human anatomy the term is used for several different spaces, most notably the vestibule of the inner ear, as well as the nasal and oral vestibules.

The vestibule of the inner ear is the central part of the bony labyrinth between the cochlea and the three semicircular canals. Its interior contains the vestibular organs utricle and saccule, each with a macula that senses linear acceleration and head position relative to gravity. The utricle responds to horizontal acceleration, the saccule to vertical. The utricle and saccule communicate with the semicircular canals and with the endolymphatic system via the vestibular aqueduct. Hair cells transduce mechanical stimuli into neural signals sent to the brain via the vestibular nerve, contributing to balance and spatial orientation.

The nasal vestibule lies just inside the nostrils and is lined by skin and hairs that help filter, humidify, and warm inspired air. The oral vestibule is the area between the lips and cheeks and teeth, bounded laterally by the dental arches; this space participates in mastication and speech and houses minor salivary glands.

Impairment of vestibular function may cause vertigo, dizziness, and imbalance. Conditions include vestibular neuritis, Menière’s disease, and benign paroxysmal positional vertigo (BPPV), which involves otoliths dislodged from the utricle into the semicircular canals. Diagnostic approaches include bedside head-impulse test, caloric testing, and imaging when needed.