Extra-Ocular Muscles

Question 1

What are the muscles of the orbit?

Answer 1

Levator Palpebrae Superioris
Superior, Inferior, Medial, Lateral Recti Muscles
Superior Oblique Muscle
Inferior Oblique Muscle

Question 2

Levator Palpebrae Superioris
Description

Answer 2

Thin, triangular muscle

Question 3

Levator Palpebrae Superioris
It is always active except ____

Answer 3

__when the eye is closed__

Question 4

Levator Palpebrae Superioris
Origin

Answer 4

Roof of Orbit above Optic Canal

Question 5

Levator Palpebrae Superior
Insertion

Answer 5

Forms wide aponeurosis inserting into:
Skin of Upper Eyelid innervated by Occulomotor Nerve
Anterior part of Superior Tarsus (muscle fibers called superior tarsal muscle) innervated by sympathetic trunk

Question 6

Levator Palpebrae Superioris
Action

Answer 6

Elevation of upper eyelid

Question 7

Levator Palpebrae Superioris
Ptosis is caused by

Answer 7

Oculomotor Nerve damage
Cervical Sympathetic Trunk damage

Ptosis is a symptom of Horner’s Syndrome

Question 8

Horner’s Syndrome is caused by …

Answer 8

damage of sympathetic nerves of the eye

Question 9

What are the symptoms of Horner’s Syndrome?

Answer 9

Ptosis
Miosis (constriction of pupil)
Anhydrosis

Question 10

What are the axes of the eyeball?

Answer 10

Horizontal Axis
Vertical Axis
Antero-posterior axes

Question 11

Axes of Eye
What does the horizontal axis divide the eyeball into?

Answer 11

Anterior and Posterior

Question 12

Axes of Eye
What does the vertical axis divide the eyeball into?

Answer 12

Medial and Lateral

Question 13

Axes of Eye
What does the anteroposterior axis divide the eyeball into?

Answer 13

Medial and Lateral

Question 14

Recti Muscles
What are the 4 recti muscles?

Answer 14

Superior Rectus
Inferior Rectus
Medial Rectus
Lateral Rectus

Question 15

Recti Muscles
Origin

Answer 15

Common Tendinous Ring surrounding Optic Canal
Junction of Superior and Inferior Orbital Fissure

Question 16

Recti Muscles
Pathway

Answer 16

Run anteriorly and attach anterior to horizontal axis

Question 17

Recti Muscles
Insertion of Medial Rectus

Answer 17

Attach to medial side of eyeball anterior to horizontal axis

Question 18

Recti Muscles
Insertion of Lateral Rectus

Answer 18

Attach to lateral side of eyeball anterior to horizontal axis

Question 19

Recti Muscles
Insertion of Superior Rectus

Answer 19

Attaches to superior side of eyeball anterior to horizontal axis (on medial side)

Question 20

Recti Muscles
Insertion of Inferior Rectus

Answer 20

Attaches to inferior side of eyeball anterior to horizontal axis (on medial side)

Question 21

Recti Muscles
Action of Lateral Rectus

Answer 21

Abduction

Question 22

Recti Muscles
Action of Medial Rectus

Answer 22

Adduction

Question 23

Recti Muscles
Action of Superior Rectus

Answer 23

Elevates
Adduction

Reminder: Superior Rectus inserts on medial surface of eyeball enabling adduction

Question 24

Rectus Muscles
Action of Inferior Rectus

Answer 24

Depression
Adduction

Reminder: Superior Rectus inserts on medial surface of eyeball enabling adduction

Question 25

**Superior Oblique Muscles** Origin

Answer 25

Sphenoid Bone Superomedial to Common Tendinous Ring

Question 26

**Superior Oblique Muscles** Pathway

Answer 26

Passes anteriorly above medial rectus Ends as round tendon which runs through trochlea

Question 27

**Superior Oblique Muscle** Insertion

Answer 27

Tendon runs posterolaterally from trochlea and inserts into sclera on superior surface posterior to horizontal axis and lateral to AP+Vertical axes

Question 28

**Superior Oblique Muscle** Action

Answer 28

Depression Abduction

Question 29

**Inferior Oblique Muscle** Origin

Answer 29

Maxilla in floor of orbit lateral to lacrimal groove

Question 30

**Inferior Oblique Muscle** Pathway

Answer 30

Pass laterally and posteriorly below Inferior Rectus

Question 31

**Inferior Oblique Muscle** Insertion

Answer 31

Into Sclera inferiorly Posterior to Horizontal Axis and Lateral to AP and Vertical Axes

Question 32

**Inferior Oblique Muscle** Action

Answer 32

Elevation Abduction

Question 33

Cranial Nerves supplying Eye Muscles

Answer 33

Occulomotor Nerve Trochlear Nerve Abducent Nerve

Question 34

How do the nerves supplying the eye muscles enter the orbit?

Answer 34

Superior Orbital Fissure

Question 35

Nerves supplying each muscle

Answer 35

**SO₄(LR₆)₃**: **Superior Oblique**: Trochlear **Lateral Rectus**: Abducent **Remaining**: Oculomotor Nerve