Muscles of eye movement

Question 1

how many muscles are involved in control of eyeball itself?

Answer 1

six muscles

Question 2

how can muscles of eye movement be divided?

Answer 2

4 recti muscles

2 oblique muscles

Question 3

what are the 4 recti muscles involved in the eye movement?

Answer 3

superior rectus, inferior rectus, medial rectus and lateral rectus

Question 4

where do the 4 recti muscles originate from?

Answer 4

common tendinous ring

Question 5

what is the common tendinous ring?

Answer 5

a ring of fibrous tissue, which surrounds the optic canal at the back of the orbit

Question 6

what does the common tendinous ring surround?

Answer 6

the optic canal at the back of the orbit

Question 7

where do the recti muscles pass from their origin?

Answer 7

pass anteriorly to attach to the sclera of the eyeball

Question 8

what does recti mean?

Answer 8

recti = straight

recti muscles have a direct path from origin to attachment

Question 9

how do you remember the innervation of the muscles to the eyes?

Answer 9

LR6SO4R3
lateral rectus = CN 6
superior oblique = CN 4
the rest = CN 3

Question 10

how many oblique muscles are there?

Answer 10

There are two oblique muscles

Question 11

what are the 3 oblique muscles?

Answer 11

superior and inferior obliques

Question 12

where do the oblique muscles originate?

Answer 12

Unlike the recti group of muscles, they do not originate from the common tendinous ring

Question 13

From their origin, which path do the oblique muscles take?

Answer 13

the oblique muscles take an angular approach to the eyeball (in contrast to the straight approach of the recti muscles)

Question 14

where do oblique muscles attach?

Answer 14

to the posterior surface of the sclera

Question 15

describe origin of the recti muscles

Answer 15

they all originate from the common tendinous ring (superior, inferior, middle, lateral) which is a group of fibrous tissue surrounding the optic canal at the back of the orbit

Question 16

describe the attachment of the recti muscles

Answer 16

they all attach to the anterior sclera (superior, inferior, medial, lateral) e.g. superior anterior sclera etc.

Question 17

innervation of recti muscles

Answer 17

superior, inferior, medial = CN III (oculomotor)

lateral rectus = CN VI (abducens)

Question 18

function of the 4 recti muscles

Answer 18

superior = elevate eyeball
inferior = depress eyeball
medial = adduct eyeball
lateral = ABduct eyeball

Question 19

what else does inferior rectus contribute to (eye movement)?

Answer 19

adduction and lateral rotation of the eyeball

Question 20

what else does superior rectus contribute to (eye movement)?

Answer 20

adduction and medial rotation of the eyeball

Question 21

what do both superior and inferior rectus contribute to (eye movement)?

Answer 21

adduction of the eyeballs

Question 22

innervation of superior and inferior oblique?

Answer 22

SO4

IO = CN III (R3)

Question 23

origin of superior oblique?

Answer 23

from the body of the sphenoid bone

Question 24

attachment of superior oblique?

Answer 24

Its tendon passes through a trochlear, and then attaches to the sclera of the eye, posterior to the superior rectus

Question 25

action of superior oblique?

Answer 25

Depresses, ABducts and medially rotates the eyeball

intorsion of the eyeball

Question 26

origin of inferior oblique?

Answer 26

anterior aspect of the orbital floor

Question 27

attachment of inferior oblique?

Answer 27

sclera of the eye, posterior to the lateral rectus

Question 28

action of internal oblique?

Answer 28

Elevates, abducts and laterally rotates the eyeball

extorsion of eyeball