Key Points

■ Vestibular input helps maintain positions of the eyes, neck, trunk and limbs that are appropriate for the head position.

■ The receptors of the vestibular system consist of three semicircular ducts detecting angular accelerations, and the utriculus and sacculus detecting static head position and linear accelerations.

■ The vestibular ganglion is located in the petrous temporal bone. CN VIII enters the cranial vault through the internal acoustic meatus and vestibular fibres synapse with four pairs of vestibular nuclei located in the rostral medulla oblongata.

■ Vestibular nuclei receive additional proprioceptive input from proprioceptors in neck muscles.

■ The vestibular system provides the cerebellum with subconscious proprioceptive information about head and neck position.

■ The output from the vestibular nuclei is modified by efferent fibres from the cerebellum.

■ Lesions in the vestibular system can cause strabismus, pathological nystagmus and loss of extensor muscle tone (usually ipsilateral).