Muscles of the Eye

Question 1

What is the difference between extrinsic ocular muscles and the intrinsic ocular muscles?

Answer 1

Extrinsic ocular muscles are on the outside of the eye; the intrinsic ocular muscles are on the inside of the globe

Question 2

Define the three positions of the eye

Answer 2

Primary position - looking straight ahead

Secondary position - looking exactly up and down vertically and exactly horizontally left or right

Tertiary position - in between secondary position, up and in or down and out

Question 3

What is the difference between adduction and abduction?

Answer 3

Adduction is when the eye moves temporally; abduction is when the eye moves nasally

Question 4

Describe the lateral rectus muscle

Answer 4

Turns the cornea outwards, located on the outside front of the eye globe

Question 5

Describe the medial rectus muscles

Answer 5

Turns the cornea inwards, located on the inside front of the eye globe

Question 6

Describe the superior rectus muscle

Answer 6

Turns the cornea upwards, located on the top front of the eye globe

Question 7

Describe the inferior rectus muscle

Answer 7

Turns the cornea downwards, located on the bottom front of the eye globe

Question 8

Describe the superior oblique muscle

Answer 8

Rolls the eyeball towards the nose, located on the lateral top back of the eye globe

Question 9

Describe the inferior oblique muscle

Answer 9

Rolls the eyeball away from the nose, located on the lateral bottom of the eye globe

Question 10

Give an example of antagonistic muscles in the eye

Answer 10

Medial and lateral muscles

Question 11

What is Sherrington’s law of equal innervation?

Answer 11

When one antagonistic muscle contacts, its counterpart will relax.