CN2 Optic nerve

Question 1

What is cranial nerve 2?

Answer 1

Optic nerve

Question 2

What covers the CN2 optic nerve? Why?

Answer 2

Meninges

because it arises from the forebrain

Question 3

What does the CN2 optic nerve innervate?

Answer 3

Retina

Question 4

What is the route of the CN2 optic nerve from its innervation to origin?

Answer 4

From optic disc
passes through optic canal
runs to optic chiasm
forms optic tracts
to primary visual cortex in occipital lobe

Question 5

What is the optic disc?

Answer 5

Where the optic nerve meets the retina

Question 6

Where is the optic chiasm located?

Answer 6

Superiorly to the pituitary gland

Question 7

What happens at the optic chiasm?

Answer 7

Fibres from the right and left optic nerves mix

Question 8

What is the function of the CN2 optic nerve?

Answer 8

Special sensory - vision

Question 9

How is the optic disc looked at during examination?

Answer 9

Opthalmoscope

Question 10

What is papillodema?

Answer 10

Swelling of the optic disc

Question 11

What causes papilloedema?

Answer 11

Increased intracranial pressure

pressure transmitted through meninges of optic nerve

Question 12

What does damage to the CN2 optic nerve result in?

Answer 12

Loss of vision in ipsilateral eye

Question 13

What does damage to the optic chiasm result in?

Answer 13

Loss of vision in both eyes

Question 14

How does a pituitary tumour affect the optic chiasm?

Answer 14

Compresses the optic chiasm

Question 15

How does a pituitary tumour compressing the optic chiasm present?

Answer 15

Bi-temporal hemi anopia

meaning tunnel vision

Question 16

How is the function of the CN2 optic nerve tested?

Answer 16

Visual tests

Test pupil reflexes to light

Test one eye at a time
to prevent the other eye compensating