The vestibular nerve carries special sensory fibres from the vestibular ganglion (Scarpa ganglion) to the vestibular nuclei of the brainstem and the cerebellum. Its peripheral fibres innervate the hair cells of the three semicircular canal cristae and the utricular and saccular maculae, detecting angular acceleration and linear acceleration respectively. It travels in the superior and inferior divisions through the internal auditory meatus alongside the facial and cochlear nerves.
The vestibular nerve is the origin of vestibular schwannoma (acoustic neuroma), which arises from the Schwann cells of the vestibular nerve in the internal auditory canal and cerebellopontine angle. Selective vestibular neurectomy, dividing the vestibular nerve while preserving the cochlear nerve, is performed for intractable Meniere disease in patients with functional hearing to eliminate the vertigo attacks while maintaining hearing. Vestibular neuritis (acute unilateral vestibulopathy) is an acute viral or post-viral inflammation of the vestibular nerve causing acute severe vertigo without hearing loss.
Acute inflammation of the vestibular nerve, thought to be viral or post-viral, produces sudden severe vertigo, nausea, and postural instability lasting days to weeks without hearing loss or tinnitus, managed with vestibular suppressants acutely and vestibular rehabilitation for the residual imbalance.
A benign Schwann cell tumour of the vestibular nerve in the internal auditory canal produces progressive unilateral hearing loss, tinnitus, and imbalance; most are sporadic and slow-growing, monitored with serial MRI or treated by microsurgical excision or stereotactic radiosurgery.
