The peripheral conduit of balance — Scarpa's ganglion, the superior and inferior divisions, the course to the brainstem, and the lesions that disrupt it: vestibular neuritis and schwannoma.
From ganglion to brainstem
The vestibular nerve carries balance information from the inner ear to the brain. It is one division of cranial nerve VIII, the vestibulocochlear nerve, travelling alongside the cochlear and facial nerves through the internal auditory canal.12
Superior and inferior divisions
The nerve has two divisions, and which sense organs each one serves is clinically important — it determines the pattern of loss when one division is affected.13
What the nerve transmits
The vestibular nerve does not simply switch on with movement. Its fibres fire continuously at a resting rate even when the head is still, and head motion pushes that rate up on one side and down on the other.3
Clinical relevance
Damage to the vestibular nerve produces an acute peripheral vestibular syndrome: sudden vertigo, horizontal-torsional nystagmus, gait instability, and nausea.38