The vestibulocochlear nerve (cranial nerve VIII) leaves the brainstem at the border of the pons and the medulla oblongata (the pontomedullary junction), in the angle between them and the cerebellum, and runs with the facial nerve into the internal acoustic meatus of the temporal bone. It carries hearing from the cochlea and balance from the vestibular organs of the inner ear. [1][2]
The 3D brain needs JavaScript. The text below still says where the vestibulocochlear nerve is and what it does.
The pons and medulla oblongata are lit together; the vestibulocochlear nerve leaves at their border and is not drawn on its own. The side (sagittal) slice button cuts through them. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part it leaves the brain from. Lit: the whole pons and the whole medulla oblongata together, since the vestibulocochlear nerve leaves at their border. The nerve itself has no shape in the BodyParts3D model, so nothing is drawn for it at a guessed point. [3][2]
Where it leaves the brain: the border of the pons and the medulla oblongata, the pontomedullary junction, at the side where they meet the cerebellum (the cerebellopontine angle), next to the facial nerve. [1][2][4]
Lit here: the pons and the medulla oblongata, the parts the vestibulocochlear nerve leaves the brain from, at their border — see each on its own page.
It is two nerves running as one: the cochlear nerve, whose cell bodies form the spiral ganglion in the cochlea, and the vestibular nerve, whose cell bodies form the vestibular ganglion. [1]
From the brainstem it runs with the facial nerve and the labyrinthine artery through the internal acoustic meatus in the temporal bone to the inner ear. [1]
It ends at the organs of hearing and balance inside the temporal bone, so unlike most cranial nerves it never reaches the outer surface of the skull. [5]
Its nuclei, the cochlear and vestibular nuclei, are counted with those of the pons. [5][6]
What it does
Hearing: the cochlear nerve carries the signals of the inner hair cells of the organ of Corti in the cochlea, which respond to sound waves reaching the basilar membrane. [1][7]
Balance: the vestibular nerve carries head movement and position from five sense organs: the three semicircular canals, which sense the head turning, and the utricle and saccule, which sense straight-line movement and gravity. [1][7]
It is a sensory nerve; a small set of olivocochlear fibres runs the other way, from the superior olivary complex in the brainstem out to the cochlea. [1][7]
Connections
From the hair cells of the inner ear (cochlea, semicircular canals, utricle and saccule) to the cochlear and vestibular nuclei of the brainstem; olivocochlear fibres run back from the superior olivary complex to the cochlea. [1]
Other names
Cranial nerve VIII (CN VIII), eighth cranial nerve, also called the auditory vestibular nerve; its two divisions are the cochlear nerve and the vestibular nerve. [1]
Size
The model has no shape for the vestibulocochlear nerve, so it is not measured here. The pons, lit as the part it leaves the brain from, measures about 34 mm front to back, 29 mm top to bottom and 42 mm side to side on this model (the box it fits in, not its volume). [3]
The medulla oblongata, lit as the part it leaves the brain from, measures about 33 mm front to back, 41 mm top to bottom and 27 mm side to side on this model (the box it fits in, not its volume). [3]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.