Motor Control of Eye Movements

Question 1

what is conjugate eye movements?

Answer 1

eyes move in the same direction

Question 2

what is a saccadic eye movement?

Answer 2

rapid movement: vision moves from target to target

Question 3

what is smooth pursuit?

Answer 3

maintains image of moving target fixed on the retina (watching a bird as it fys past)

Question 4

what is vergence?

Answer 4

focus shifts between near and far objects
(eyes move in opposite directions

Question 5

what is conversance eye movement?

Answer 5

visual axis of eyes converge (near focus)(eyes look to nose)

Question 6

what is divergence eye movement?

Answer 6

visual axis of eyes diverge (far focus) (eyes out lateral)

Question 7

CN III innervates which eye muscles?

Answer 7

Medial rectus muscle
Inferior rectus muscle
Superior rectus muscle
Inferior oblique muscle
(levator palpebrae superioris m)

Question 8

What is innervated by CN IV?

Answer 8

superior oblique

Question 9

what does CN VI innervate?

Answer 9

lateral rectus m

Question 10

if you ask patient to ook straight ahead and eye goes in and up what nerve may be damaged?

Answer 10

abducens (CN VI)

Question 11

WHAT IS THE ACTION of superior oblique?

Answer 11

down and out

Question 12

what is the action of inferior oblique?

Answer 12

up and out

Question 13

when looking to the wight which part of the brain is acting?

Answer 13

left

Question 14

when we want to move our eyes right what is the path of efferent?

Answer 14

info leaves the eft frontal eye field, decussates, goes to right PPRF and then to right abducens
for left eye must go to left PPRF in PONS then to left longitudinal fasciculus to oculomotor

Question 15

where are the different gaze centers?

Answer 15

horizontal gaze center: PONS
Vertica and vergence: midbrain

Question 16

how would a lesion at the left frontal eye field impact eye movement?

Answer 16

transient paralysis of gaze to right

Question 17

how would a lesion to the PPRF effect attempted right eye movement?

Answer 17

effect right gaze center PPRF cause paralysis of gaze to right

Question 18

how would a lesion of the left MlF effect attempted gaze to right?

Answer 18

left internuclear ophthalmoplegia

Question 19

how would a lesion of the right abducens nerve effect gaze to the right?

Answer 19

abductor paralysis in right eye

Question 20

where is the vertical gaze center located?

Answer 20

rostral midbrain

Question 21

where does the fibers of the vertical gaze center cross?

Answer 21

posterior commissure (near pineal gland so if issue there could cause issue to this)

Question 22

what does the vertical gaze center project to?

Answer 22

oculomotor subnuclei

Question 23

where is the vergence gaze center?

Answer 23

rostral midbrain at reticular formation

Question 24

where does the vergence gaze center project to?

Answer 24

CN III (convergence)
CN VI (divergence)

Question 25

what originates at the frontal eye field?

Answer 25

voluntary saccadic movement

Question 26

what to the frontal field project to?

Answer 26

vertical and horizontal gaze centers and superior colliculus

Question 27

what happens at the temporal and parietal eye fields?

Answer 27

parietal- saccadic movement
temporal- smooth pursuit

Question 28

what is the occipital eye field a origin of and what focus us it?

Answer 28

vergence
focus shift: faraway to near target (signal to oculomotor or abducens)

Question 29

what travels through the SOF?

Answer 29

CN III
CN IV
CN VI
CN V3

Question 30

what is the only eye muscle not attached to back eye socket?

Answer 30

inferior oblique

Question 31

if a patient’s eye is stuck in and up what muscle has an issue?

Answer 31

superior oblique because it pulls eye down and out so if it is not working the interior is unopposed so it pulls in and up

Question 32

what is the part that holds the tendon of the superior ob called?

Answer 32

trochlea

Question 33

how do you test cranial nerves in the eyes?

Answer 33

by moving the eyes to see which muscles can/cant move

Question 34

what test would you do for superior oblique?

Answer 34

eye adduct, then down

Question 35

in medica terms what are the actions of superior and inferior oblique?

Answer 35

S: intorsion
I: extorsion

Question 36

how can you tell if a patient has CN IV palsy?

Answer 36

normal eye rotation
BUT when head tilts to left both eyes rotate same way (right eye extort, left eye intort)

Question 37

what is important to note about venous drainage in the face and orbit?

Answer 37

ophthalmic vein goes into cavernous sinus and so many important structures run through it so it is a critical zone (pit gland, internal carotid a, CNs)