Vestibulocochlear nerve

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Nerve: Vestibulocochlear nerve
Image:Gray789.png
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.

1 Structure
2 Functions
3 Innervations
4 Physiology
5 Symptoms of damage
6 Name
7 Additional images
8 External links

Structure

This is the 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.

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.

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.

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.

Symptoms of damage

vertigo, false sense of motion, loss of equilibrium (dark places), nystagmus, motion sickness

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.

Additional images

Gray689.png Superficial dissection of brain-stem. Ventral view.	Gray705.png Dissection showing the projection fibers of the cerebellum.	Gray719.png Hind- and mid-brains; postero-lateral view.	Gray792.png Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.
Gray922.png Position of the right bony labyrinth of the ear in the skull, viewed from above.	Vestibulo-ocular reflex

External links

v • d • e

Nerves of head and neck: the cranial nerves

olfactory (AON->I)

olfactory bulb - olfactory tract

optic (LGN->II)

optic chiasm - optic tract

oculomotor (ON,EWN->III)

superior branch (ciliary ganglion) - inferior branch

trochlear (TN->IV)

no significant branches

trigeminal (PSN,TSN,MN,TMN->V)

trigeminal ganglion • ophthalmic • maxillary • mandibular

abducens (AN->VI)

no significant branches

facial (FMN,SN,SSN->VII)

near origin	nervus intermedius • geniculate
inside facial canal	greater petrosal (pterygopalatine ganglion) - nerve to the stapedius - chorda tympani (lingual nerve, submandibular ganglion)
at stylomastoid foramen	posterior auricular - suprahyoid (digastric, stylohyoid) - parotid plexus (temporal, zygomatic, buccal, mandibular, cervical)

vestibulocochlear (VN,CN->VIII)

cochlear (striae medullares, lateral lemniscus) • vestibular (Scarpa's ganglion)

glossopharyngeal (NA,ISN,SN->IX)

before jugular fossa	ganglia (superior, inferior)
after jugular fossa	tympanic (tympanic plexus, lesser petrosal, otic ganglion) • stylopharyngeal branch • pharyngeal branches • tonsillar branches • lingual branches • carotid sinus

vagus (NA,DNVN,SN->X)

before jugular fossa	ganglia (superior, inferior)
after jugular fossa	meningeal branch - auricular branch
neck	pharyngeal branch (pharyngeal plexus) - superior laryngeal (external, internal) - recurrent laryngeal (inferior) - superior cervical cardiac
thorax	inferior cardiac - pulmonary - vagal trunks (anterior, posterior)
abdomen	celiac - renal - hepatic - anterior gastric - posterior gastric