Muscles of the Orbit

Question 1

Levator Palpebrae Superioris Action

Answer 1

Elevates the upper eyelid

Question 2

Levator Palpebrae Superioris Origin and Insertion

Answer 2

Origin:
Lesser wing of the sphenoit (anterior and superior to the optic canal)

Insertion:
Tarsal plate and skin of the upper eyelid

Question 3

Levator Palpebrae Superioris nerve supply

Answer 3

Oculomotor Nerve CN III

-Some deep layer supplied by sympathetic nerves (open eye)

Question 4

Levator Palpebrae Superioris extra info

Answer 4

Thin flat muscle

Question 5

Rectus Muscles nerve supply

Answer 5

Superior, inferior and medial: Oculomotor Nerve CN III

Lateral: Abducent Nerve CN VI

Question 6

Superior Rectus Muscle Action

Answer 6

Elevates, adducts, and laterally rotates the eye

Question 7

Superior Rectus Muscle Origin and Insertion

Answer 7

Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF

Insertion:
Sclera just posterior to the cornea

Question 8

Superior Rectus Muscle extra info

Answer 8

The pull of superior and inferior rectus is not parallel to the long axis of the eyeball hence adduction

Question 9

Inferior Rectus Muscle Action

Answer 9

Depresses, adducts, and laterally rotates the eye

Question 10

Inferior Rectus Muscle Origin and Insertion

Answer 10

Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF

Insertion:
Sclera just posterior to the cornea

Question 11

Medial Rectus Muscle Action

Answer 11

Adducts the eyeball

Question 12

Medial Rectus Muscle Origin and Insertion

Answer 12

Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF

Insertion:
Sclera just posterior to the cornea

Question 13

Lateral Rectus Muscle Action

Answer 13

Abducts the eyeball

Question 14

Lateral Rectus Muscle Origin and Insertion

Answer 14

Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF

Insertion:
Sclera just posterior to the cornea

Question 15

Superior Oblique Action

Answer 15

Abducts, depresses, and medially rotates the eyeball

Question 16

Superior Oblique Origin and Insertion

Answer 16

Origin:
Body of the sphenoid

Insertion:
Sclera, deep to superior rectus muscle

Question 17

Superior Oblique nerve supply

Answer 17

Trochlea Nerve CN IV

Question 18

Superior Oblique extra info

Answer 18

Its tendon passes through a fibrous ring (trochlea) lined with a synovial sheath allows easy slide, causes it to change direction

Question 19

Inferior Oblique Action

Answer 19

Abducts, elevates, and laterally rotates the eye

Question 20

Inferior Oblique Origin and Insertion

Answer 20

Origin:
Anterior part of the floor of the orbit

Insertion:
Sclera deep to the lateral rectus muscle

Question 21

Inferior Oblique nerve supply

Answer 21

Oculomotor Nerve CN III