Visual Pathway and Extra-ocular Muscles

Question 1

light from the left visual field hits where

Answer 1

the nasal field of the left eye and the temporal field of the right

Question 2

light from the right visual field hits where

Answer 2

the nasal field of the right eye and the temporal field of the left

Question 3

what happens at the optic chiasm

Answer 3

optic nerves cross over and all the information from the left and right visual fields are processed together

Question 4

at the primary visual cortex where is the information from the right visual field processed

Answer 4

left visual cortex

Question 5

at the primary visual cortex where is the information from the left visual field processed

Answer 5

right visual cortex

Question 6

what does the vertical axis of the eye determine

Answer 6

the direction of gaze in an adducted or abducted position

Question 7

what does the transverse axis of the eye determine

Answer 7

the direction of gaze but in terms of elevation and depression

Question 8

what does the anteroposterior axis of the eye determine

Answer 8

the superior pole of the eyeball with intorsion/extorsion

Question 9

function and innervation of lateral rectus

Answer 9

• abduction

- CN VI (abducent)

Question 10

function and innervation of superior rectus

Answer 10

• elevated eye (in abduction)

- CN III (oculomotor)

Question 11

function and innervation of inferior rectus

Answer 11

• depress eye (in abduction)

- CN III (oculomotor)

Question 12

function and innervation of medial rectus

Answer 12

• adduct eye

- CN III (oculomotor)

Question 13

function and innervation of inferior oblique

Answer 13

• elevated eye (in adduction)

- CN III (oculomotor)

Question 14

function and innervation of superior oblique

Answer 14

• depress eye (in adduction)

- CN IV (trochlear)

Question 15

how are muscles of the eye clinically tested

Answer 15

to get the true movements of muscles the movement has to be isolated and so elevation and depression must occur in adduction or abduction

Question 16

where do all rectus mucscles originate from and insert

Answer 16

a common tendinous ring

sclera

Question 17

where does the superior oblique originate and insert

Answer 17

sphenoid bone

sclera

Question 18

where does the inferior oblique originate and insert

Answer 18

orbital plate of maxilla

sclera

Question 19

where does the levator palpebrae superioris originate from and insert

Answer 19

lesser wing of the sphenoid

skin and tarsus of superior eyelid

Question 20

innervation mnemonic

Answer 20

LR6 SO4 AO3
lateral rectus - CN VI
superior oblique - CN IV
all others - CN III