CN6 Abducens nerve

Question 1

What is cranial nerve 6?

Answer 1

Abducens nerve

Question 2

What does the CN6 abducens nerve innervate?

Answer 2

Lateral rectus muscle

which is one of the extra-ocular muscles

Question 3

What is the function of the lateral rectus muscle?

Answer 3

Abducts eye

Question 4

What is the function of the CN6 abducens nerve?

Answer 4

Motor - lateral rectus muscle

Question 5

What is the route of the CN6 abducens nerve from its origin to its innervation?

Answer 5

Passes through cavernous sinus
through superior orbital fissure
into orbit

Question 6

What are the causes of damage to the CN6 abducens nerve?

Answer 6

Raised intracranial pressure due to tumour, haemorrhage

Question 7

What are the consequences of damage to the CN6 abducens nerve?

Answer 7

Eye is pulled in medial position
can’t move eye laterally

Diplopia

Question 8

How is the function of the CN6 abducens nerve tested?

Answer 8

Eye movements

Question 9

Why is the eye pulled in a medial position with damage to the CN6 abducens nerve?

Answer 9

Unopposed pull of medial rectus muscle

Question 10

Why can’t the eye be moved laterally with damage to the CN6 abducens nerve?

Answer 10

Loss of innervation to lateral rectus muscle which moves eye laterally