CN8 Vestibulocochlear nerve

Question 1

What is cranial nerve 8?

Answer 1

Vestibulocochlear nerve

Question 2

What is the route of the CN8 vestibulocochlear nerve, from its origin?

Answer 2

Passes through internal auditory meatus

divides into vestibular and cochlear branches

Question 3

What does the vestibular branch of the CN8 vestibulocochlear nerve innervate?

Answer 3

Semi circular canals of inner ear

Question 4

What does the cochlear branch of the CN8 vestibulocochlear nerve innervate?

Answer 4

Cochlea of inner ear

Question 5

What is the function of the vestibular branch of the CN8 vestibulocochlear nerve?

Answer 5

Special sensory - balance

Question 6

What is the function of the cochlear branch of the CN8 vestibulocochlear nerve?

Answer 6

Special sensory - hearing

Question 7

What does damage to the vestibular branch of the CN8 vestibulocochlear nerve result in?

Answer 7

Loss of balance

Nystagmus

Question 8

What is nystagmus?

Answer 8

Involuntary eye movement

Question 9

What does damage to the cochlear branch of the CN8 vestibulocochlear nerve result in?

Answer 9

Loss of hearing

Question 10

How are the functions of the CN8 vestibulocochlear nerve tested?

Answer 10

Test hearing

in one ear at a time

Question 11

What is an acoustic neuroma?

Answer 11

Benign tumours of Schwann cells surrounding the vestibular branch of the CN8 vestibulocochlear nerve

Question 12

What do acoustic neuromas compress as they grow?

Answer 12

Compress the whole vestibulocochlear nerve

Compress nearby cranial nerves e.g. facial nerve, then trigeminal nerve

Question 13

What are the signs and symptoms of an acoustic neuroma?

Answer 13

Unilateral hearing loss

Loss of balance

Weakness on that side of face

Loss of sensation in parts of that side of face