Extraocular Muscles

Question 1

list extraocular muscles

Answer 1

medial/lateral rectus, superior/inferior rectus, superior/inferior oblique

Question 2

lateral rectus action

Answer 2

abduction

Question 3

lateral rectus innervation

Answer 3

abducens (VI)

Question 4

medial rectus action

Answer 4

adduction

Question 5

medial rectus innervation

Answer 5

oculomotor (III)

Question 6

superior rectus action

Answer 6

elevation and adduction

Question 7

superior rectus innervation

Answer 7

oculomotor (III)

Question 8

inferior rectus action

Answer 8

depression and adduction

Question 9

inferior rectus innervation

Answer 9

oculomotor (III)

Question 10

superior oblique action

Answer 10

depression and abduction

Question 11

superior oblique innervation

Answer 11

trochlear (IV)

Question 12

inferior oblique action

Answer 12

elevation and abduction

Question 13

inferior oblique innervation

Answer 13

oculomotor (III)

Question 14

action to test lateral rectus

Answer 14

look lateral

Question 15

action to test medial rectus

Answer 15

look medial

Question 16

action to test superior rectus

Answer 16

look lateral, then up

Question 17

action to test inferior rectus

Answer 17

look lateral, then down

Question 18

action to test inferior oblique

Answer 18

look medial, then up

Question 19

action to test superior oblique

Answer 19

look medial, then down

Question 20

oculomotor nerve injury characteristics

Answer 20

affected eye will be “down and out,” ptosis, mydriasis

Question 21

explain oculomotor nerve injury characteristics

Answer 21

only trochlear (superior oblique) and abducens (abduction) will be functioning, causing the eye to drift inferiorly and laterally

Question 22

trochlear nerve injury characteristics

Answer 22

affected eye will drift upward, mild adduction, with worsening symptoms on looking down. Looking down and out causes diplopia, and pt tilts head to unaffected side

Question 23

explain trochlear nerve injury characteristics

Answer 23

the superior oblique will not work, so the ability of the eye to look downward will be diminished

Question 24

abducens nerve injury characteristics

Answer 24

affected eye will drift medially

Question 25

explain abducens nerve injury characteristics

Answer 25

the lateral rectus will not work, so eye cannot abduct and will adduct instead

Question 26

eyelid muscle innervated by CN III

Answer 26

levator palpebrae superioris

Question 27

esotropia

Answer 27

adducted eye at rest

Question 28

strabismus

Answer 28

weakness of eye muscle(s)