Eighth cranial nerve

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

Anatomy

The vestibulocochlear nerve is composed of two distinct parts:

• The cochlear nerve, which carries information about hearing from the cochlea.
• The vestibular nerve, which carries information about balance from the vestibular apparatus.

These two components travel together from the inner ear to the brainstem, where they enter the brain at the junction of the pons and the medulla oblongata.

Function

The primary functions of the vestibulocochlear nerve are:

• Hearing: The cochlear nerve transmits auditory information from the cochlea, a spiral-shaped organ in the inner ear, to the auditory cortex in the brain.
• Balance: The vestibular nerve transmits information about head position and movement from the semicircular canals and otolithic organs in the inner ear to the vestibular nuclei in the brainstem.

Clinical significance

Damage to the vestibulocochlear nerve can result in:

• Hearing loss
• Tinnitus (ringing in the ears)
• Vertigo (a sensation of spinning or dizziness)
• Balance disorders

Common causes of damage include acoustic neuroma, Meniere's disease, and vestibular neuritis.

Testing

The function of the vestibulocochlear nerve can be assessed using various tests, including:

• Audiometry for hearing assessment
• Electronystagmography (ENG) or videonystagmography (VNG) for balance assessment

See also

• Cranial nerves
• Inner ear
• Hearing loss
• Balance disorder

References

Susan,

 Gray's Anatomy: The Anatomical Basis of Clinical Practice, 
 41st edition, 
 Elsevier, 
 2016, 
  
  
 ISBN 978-0-7020-5230-9,

External links

• Eighth cranial nerve on WikiMD