EOMs

Question 1

What type of eye movements have to do with the Z axis?

Answer 1

Adduction and abduction.

Question 2

What type of eye movements have to do with the X axis?

Answer 2

Elevation and depression.

Question 3

What type of eye movements have to do with the Y axis?

Answer 3

Intorsion and extorsion.

Question 4

Where do the rectus muscles originate?

Answer 4

The common tendinous ring (Annulus of Zinn)

Question 5

What is another name for the Annulus of Zinn?

Answer 5

Common tendinous ring.

Question 6

Where do the rectus muscles insert?

Answer 6

on the Spiral of Tillaux.

Question 7

What is meant by the term “Spiral” of Tillaux?

Answer 7

Beginning with the medial rectus muscle and moving around clockwise (as looking at the eye), the distance between the muscle insertion and limbus progressively grows larger

Question 8

Where does the medial rectus muscle originate?

Answer 8

The common tendinous ring and the optic nerve sheath.

Question 9

Where does the medial rectus muscle insert?

Answer 9

Anterior globe.

Question 10

What is the action of the medial rectus muscle?

Answer 10

Adduction.

Question 11

Where does the lateral rectus muscle originate?

Answer 11

The common tendinous ring and the greater wing of the sphenoid.

Question 12

Where does the lateral rectus muscle insert?

Answer 12

Anterior globe.

Question 13

What is the action of the lateral rectus muscle?

Answer 13

Abduction.

Question 14

What nerve innvervates the lateral rectus muscle?

Answer 14

The abducens nerve (CN VI).

Question 15

Where does the superior rectus muscle originate?

Answer 15

Common tendinous ring and optic nerve sheath.

Question 16

Where does the superior rectus muscle insert?

Answer 16

Superior, anterior globe.

Question 17

What nerve innvervates the medial rectus muscle?

Answer 17

Inferior division of oculomotor nerve (CN III).

Question 18

What is the action of the superior rectus muscle?

Answer 18

Primary action is elevation. Secondary actions are adduction and intorsion.

Question 19

Where does the inferior rectus muscle originate?

Answer 19

Common tendinous ring

Question 20

Where does the inferior rectus muscle insert?

Answer 20

Inferior, anterior globe.

Question 21

What is the action of the inferior rectus muscle?

Answer 21

Primary action is depression. Secondary actions are adduction and extorsion.

Question 22

What nerve innvervates the inferior rectus muscle?

Answer 22

Inferior division of oculomotor (CN III).

Question 23

Where is the superior oblique muscle located?

Answer 23

The muscle belly lies superior to the muscle cone and makes an angle of approximately 55 degress with the Y axis.

Question 24

Where does the superior oblique muscle originate?

Answer 24

Anatomic: Lesser wing of the sphenoid.Physiologic: Trochlea

Question 25

Where does the superior oblique muscle insert?

Answer 25

Superior, posterior, lateral globe.

Question 26

What is the action of the superior oblique muscle?

Answer 26

Primary action is intorsion. (Contraction causing the globe to move toward the trochlea.)Secondary actions are depression and abduction.

Question 27

What nerve innervates the superior oblique muscle?

Answer 27

The trochlear nerve (CN IV).

Question 28

Where is the inferior oblique muscle located?

Answer 28

Inferior to the muscle cone.

Question 29

Where does the inferior oblique muscle originate?

Answer 29

Medial maxillary bone.

Question 30

Where does the inferior oblique muscle insert?

Answer 30

Inferior, posterior, lateral globe.

Question 31

What is the action of the inferior oblique muscle?

Answer 31

Primary action is extorsion. Secondary actions are elevation and abduction.

Question 32

What nerve innervates the inferior oblique muscle?

Answer 32

Inferior division of oculomotor (CN III).

Question 33

In the sarcomere, what portion is the I band?

Answer 33

Where there are only thin fibers.

Question 34

In the sarcomere, what portion is the H zone?

Answer 34

Where there are only thick fibers.

Question 35

In the sarcomere, what portion is the A zone?

Answer 35

Where the thin and thick fibers overlap.

Question 36

What nerve innvervates the superior rectus muscle?

Answer 36

Superior division of oculomotor (CN III).

Question 37

How long is the medial rectus tendon?

Answer 37

3.7 mm

Question 38

How long is the inferior rectus tendon?

Answer 38

5.5 mm

Question 39

How long is the lateral rectus tendon?

Answer 39

8.8 mm

Question 40

How long is the superior rectus tendon?

Answer 40

5.8 mm

Question 41

How far from the limbus is the tendon of the medial rectus muscle?

Answer 41

5.5 mm

Question 42

How far from the limbus is the tendon of the inferior rectus muscle?

Answer 42

6.5 mm

Question 43

How far from the limbus is the tendon of the lateral rectus muscle?

Answer 43

6.9 mm

Question 44

How far from the limbus is the tendon of the superior rectus muscle?

Answer 44

7.7 mm

Question 45

What is meant by secondary position?

Answer 45

Adducted or abducted.

Question 46

Who came up with the law of reciprocal innervation?

Answer 46

Sherrington.

Question 47

Who came up with the law of equal innervation?

Answer 47

Hering.

Question 48

What is the purpose of the check ligaments?

Answer 48

They connect the EOMs to the bones of the orbit, and may acts to limit movement.

Question 49

Why are the CT sleeves or pullys in the orbits important?

Answer 49

They help attach the EOMs to the orbital wall or to Tenon's capsule; they also help refine coordination of binocular movements. Displacement can clinically mimic oblique dysfunction.