Vestibulocochlear nerve

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Nerve: Vestibulocochlear nerve
The course and connections of the facial nerve in the temporal bone
Gray's	subject #203
To	cochlear nerve, vestibular nerve
MeSH	Vestibulocochlear+Nerve

The vestibulocochlear nerve (also known as the auditory or acoustic nerve) is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain.

Contents 1 Structure 2 Functions 3 Innervations 4 Physiology 5 Name 6 Additional images 7 External links

[edit] Structure

This nerve, along which the sensory cells (the hair cells) of the inner ear transmit information to the brain. It consists of the cochlear nerve, carrying information about hearing, and the vestibular nerve, carrying information about balance. It emerges from the medulla oblongata and enters the inner skull via the internal acoustic meatus (or internal auditory meatus) in the temporal bone, along with the facial nerve.

[edit] Functions

The eighth cranial nerve has two prime roles. It is needed to convey information of vestibular sensation - that is, the position and movement of the head. Secondly, it is used for hearing.

[edit] Innervations

The nerve splits into two large divisions - the cochlear nerve and the vestibular nerve. Broadly speaking, the cochlear nerve innervates the cochlea, while the vestibular nerve goes to the vestibular apparatus.

[edit] Physiology

How hearing information is coded on the nerve has long been a matter of scientific debate between two competing theories, a place theory and a rate theory.

[edit] Name

Some older texts call the nerve the acoustic or auditory nerve [1], but these terms have fallen out of widespread use because they fail to recognize the nerve's role in the vestibular system. Vestibulocochlear nerve is therefore preferred by most.

[edit] Additional images

Superficial dissection of brain-stem. Ventral view.	Dissection showing the projection fibers of the cerebellum.	Hind- and mid-brains; postero-lateral view.	Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.
Position of the right bony labyrinth of the ear in the skull, viewed from above.

[edit] External links

• MedEd at Loyola GrossAnatomy/h_n/cn/cn1/cn8.htm
• Norman/Georgetown cranialnerves (VIII)

v • d • e Nerves of head and neck: the cranial nerves

I-IV: olfactory - optic - oculomotor (superior branch, inferior branch) - trochlear V: trigeminal: trigeminal ganglion V1: ophthalmic: lacrimal - frontal (supratrochlear, supraorbital) - nasociliary (long root of ciliary, long ciliary, infratrochlear, posterior ethmoidal, anterior ethmoidal) - ciliary ganglion (short ciliary) V2: maxillary: middle meningeal - in the pterygopalatine fossa (zygomatic, zygomaticotemporal, zygomaticofacial, sphenopalatine, posterior superior alveolar) in the infraorbital canal/infraorbital nerve (middle superior alveolar, anterior superior alveolar) on the face (inferior palpebral, external nasal, superior labial, infraorbital plexus) - pterygopalatine ganglion (deep petrosal, nerve of pterygoid canal) branches of distribution (greater palatine, lesser palatine, nasopalatine, pharyngeal) V3: mandibular: meningeal - medial pterygoid - anterior (masseteric, deep temporal, buccal, lateral pterygoid) posterior (auriculotemporal, lingual, inferior alveolar, mylohyoid, mental) - otic ganglion - submandibular ganglion VI: abducens VII: facial: nervus intermedius - geniculate - inside facial canal (greater petrosal, nerve to the stapedius, chorda tympani) at exit from stylomastoid foramen (posterior auricular, digastric - stylohyoid) on face (temporal, zygomatic, buccal, mandibular, cervical) VIII: vestibulocochlear: cochlear (striae medullares, lateral lemniscus) - vestibular (Scarpa's ganglion) IX: glossopharyngeal: nucleus ambiguus - ganglia (superior, petrous) - tympanic (tympanic plexus, lesser petrosal) - carotid sinus - pharyngeal branches - pharyngeal plexus X: vagus: ganglia (jugular, nodose) - Alderman's nerve - in the neck (pharyngeal branch, superior laryngeal ext and int, recurrent laryngeal) in the thorax (pulmonary branches, esophageal plexus) - in the abdomen (gastric plexuses, celiac plexus, gastric plexus) XI: accessory XII: hypoglossal