3 - Anatomy of the Eye

Question 1

what is the annulus of zinn?

Answer 1

oval shaped thickening of the periosteum at the orbital apex that enclosed the optic canal and part of the superior orbital fissure

Question 2

draw a diagram of the anterior view of the rectus insertions

Answer 2

Question 3

what is the primary position of the eyeball?

Answer 3

looking straight ahead

Question 4

what are the secondary positions of the eyeballs?

Answer 4

up
down
left
right

Question 5

what are the tertiary positions of the eyeball?

Answer 5

eye directed diagonally

Question 6

what is pitching of the eye?

Answer 6

elevation and depression

Question 7

what is rolling of the eye?

Answer 7

intorsion and extorsion

Question 8

what is yawing of the eye?

Answer 8

abduction and adduction

Question 9

all recti muscles do what?

Answer 9

pull medially

Question 10

what is the action of the medial and lateral recti?

Answer 10

produce rotation around vertical axis - yawing (adducting and abducting respectively)

Question 11

what is the action of the superior and inferior recti?

Answer 11

produce rotation around the transverse axis - pitching (elevation and depression respectively)

Question 12

when the eye is abducted to 23 degrees, which muscles pull the eye vertically?

Answer 12

superior and inferior rectus

Question 13

when the eye is adducted to 51-55 degrees, which muscles pull the eye vertically?

Answer 13

superior and inferior oblique

Question 14

if the eye cannot abduct there is a problem with what muscle?

Answer 14

lateral rectus

Question 15

if the eye cannot adduct there is a problem with what muscle?

Answer 15

medial rectus

Question 16

what is binocular vision?

Answer 16

eyeballs move in the same direction and lines of sight of each eyeball remian parallel

Question 17

supraversion

Answer 17

eyes move in parallel upwards

Question 18

infraversion

Answer 18

eyes move in parallel downwards

Question 19

dextroversion

Answer 19

eyes move in parallel right

Question 20

levoversion

Answer 20

eyes move in parallel left

Question 21

what extraocular muscles are innervated by the oculomotor nerve?

Answer 21

• inferior oblique
• LPS
• superior rectus
• medial rectus
• inferior rectus

Question 22

what extraocular muscle is innervated by the abducens nerve?

Answer 22

lateral rectus

Question 23

what extraocular muscle is innervated by the trochlear nerve?

Answer 23

superior oblique

Question 24

what is the oculomotor nuclei important for?

Answer 24

coordinating eye movement

Question 25

what is the course of the oculomotor nerve?

Answer 25

passes through cavernous sinus and leaves cranial cavity through superior orbital fissure

Question 26

where are the Edinger-Westphal nuclei located?

Answer 26

posterior to the main nuclei

Question 27

what is the role of the edinger-westphal nuclei?

Answer 27

• accomodation reflex
• direct and consensual light reflexes

Question 28

the fibres of the oculomotor nerve synapse where?

Answer 28

ciliary ganglion

Question 29

where do the trochlear nerve nuclei originate?

Answer 29

neuronal cell bodies at the border of pons and midbrain

Question 30

where are the trochlear nerve nuclei located?

Answer 30

grey matter surrounding cerebral aqueduct

Question 31

where does the abducens nerve nuclei originate?

Answer 31

neuronal cell bodies beneath the floor of the fourth ventricle

Question 32

what is diplopia?

Answer 32

double vision

Question 33

what does diplopia indicate?

Answer 33

• fatigue
• cranial nerve dysfunction
• raised intracranial pressure
• cerebellar dysfunction
• blow-out fractures of the orbit

Question 34

what gives sensory innervation to the CN III, IV, VI (oculomotor, trochlear, abducens)?

Answer 34

proprioception from the eye muscles