Glossary
Vestibular System
What is the vestibular system?
The vestibular system includes sensory organs in the inner ear, the vestibular nerve, and central brain pathways. It contributes to balance, spatial orientation, and coordination of eye movements.
In this context, vestibular refers to this balance and orientation system. The vestibular sense provides information about head movement and position; it works alongside sight and the sense of body position.
Inner-ear structures
The sensors include three semicircular canals and two otolith organs, the utricle and saccule. Specialized hair cells respond to head movement and position, providing information for further processing.
Functions
- Balance and orientation: Vestibular information combines with vision and proprioception, the sense of body position, to help coordinate posture and movement.
- Vestibulo-ocular reflex (VOR): Eye movements compensate for head movement to help keep the visual scene stable. This is one reason you can move your head while keeping a target in view.
Associated conditions
- Vertigo is a false sensation of movement, often spinning. It is a symptom, not one disease, and not all dizziness is vestibular.
- Vestibular neuritis, also called vestibular neuronitis, can involve severe vertigo, imbalance, and nausea. A viral cause is suspected in some cases.
- Ménière's disease can involve episodes of vertigo, fluctuating hearing loss, tinnitus, and ear fullness. Its cause is not fully understood.
Why it matters
Balance depends on several sources of information working together. The vestibular system is part of that process.