Extra ocular muscles of Eye, its anatomy and physiology.

1. UNIT 3
ExtraOcul
ar
Muscle

2. ANATOMY

3. Rajeswari.K-EOM
1. Muscles Involved
2. Origin
3. Course
4. Insertion
5. Blood supply
6. Nerve supply

4. Rajeswari.K-EOM
MUSCLES INVOLVED
Rectus muscle
1) Inferior Rectus Muscle
2) Superior Rectus Muscle
3) Medial Rectus Muscle
4) Lateral Rectus Muscle
Oblique muscle
1) Inferior Oblique Muscle {shortest}
2) Superior Oblique Muscle {longest}

5. Rajeswari.K-EOM
ORIGIN
Inferior Rectus Muscle Inferior Part of Common Tendinous Ring*
Superior Rectus Muscle Superior Part of Common Tendinous Ring*
Medial Rectus Muscle Medial Part of Common Tendinous Ring*
Lateral Rectus Muscle Lateral Part of Common Tendinous Ring*
Inferior Oblique Muscle Orbital Plate of Maxilla Bone
Superior Oblique Muscle Body of Sphenoid Bone
*also called as Annulus of Zinn

6. Rajeswari.K-EOM

7. Rajeswari.K-EOM
COURSE
Inferior Rectus Muscle
Follows along Floor of Orbit and
takes gentle curve to front of eye
ball
Superior Rectus Muscle
Follows along Roof of Orbit takes
gentle curve to front of eye ball
Medial Rectus Muscle
Follows along Medial Walls of Orbit
takes gentle curve to front of eye
ball
Lateral Rectus Muscle
Follows along Lateral Walls of
Orbit takes gentle curve to front
of eye ball
Inferior Oblique Muscle
Move between Floor & Inferior
Rectus Muscle
Superior Oblique Muscle Move between Roof & Medial Wall

8. Rajeswari.K-EOM

9. Rajeswari.K-EOM
INSERTION
Inferior Rectus Muscle Into Sclera @ 6.5mm away from Limbus*
Superior Rectus Muscle Into Sclera @ 7.7mm away from Limbus*
Medial Rectus Muscle Into Sclera @ 5.5mm away from Limbus*
Lateral Rectus Muscle Into Sclera @ 6.9mm away from Limbus*
Inferior Oblique Muscle Lower & Outer part of Sclera
Superior Oblique Muscle Upper & Outer part of Sclera
*Junction between Sclera & Cornea

10. Rajeswari.K-EOM
BLOOD SUPPLY
IR Medial Muscular branch of Opthalmic Artery & Infraorbital Artery
SR Lateral Muscular branch of Opthalmic Artery
MR Medial Muscular branch of Opthalmic Artery & Lacrimal Artery
LR Lateral Muscular branch of Opthalmic Artery
IO Medial Muscular branch of Opthalmic Artery & Infraorbital Artery
SO Lateral Muscular branch of Opthalmic Artery
Muscular Artery (branch of Opthalmic Artery) has two branches –
Medial & Lateral
Superior & Inferior
Ophthalmic Veins

11. Rajeswari.K-EOM
CRANIAL NERVES
1. Olfactory nerve
2. Optic nerve
3. Oculomotor nerve
4. Trochlear nerve
5. Trigeminal nerve
6. Abducent nerve
6. Facial nerve
7. Vestibulococlear nerve
8. Glossopharyngeal nerve
9. Vagus nerve
10. Accessory nerve
11. Hypoglossal nerve

12. Rajeswari.K-EOM
NERVE SUPPLY
Inferior Rectus Muscle
Oculomotor Nerve (3rd Cranial
Nerve)
Superior Rectus Muscle
Oculomotor Nerve (3rd Cranial
Nerve)
Medial Rectus Muscle
Oculomotor Nerve (3rd Cranial
Nerve)
Lateral Rectus Muscle
Abducent Nerve (6th Cranial
Nerve)
Inferior Oblique Muscle
Oculomotor Nerve (3rd Cranial
Nerve)
Superior Oblique Muscle
Trochlear Nerve (4th Cranial
Nerve)
SO4 & LR6

13. Rajeswari.K-EOM
ACTIONS
Rule 1:
➤Oblique Muscles 1˚action Is Torsional Movement
➤Recti Muscles 1˚action Is ADD/ABD
Rule 2:
➤Superior Muscles Extort
➤Inferior Muscles Intort

14. Rajeswari.K-EOM
LR
ACTIONS
SR
IR
IO
SO
MR
Adduction
Abduction
Depression
Elevation

15. Rajeswari.K-EOM
Muscle Primary Secondary Tertiary
MR Adduction - -
LR Abduction - -
SR Elevation Intortion Adduction
IR Depression Extortion Adduction
SO Intortion Depression Abduction
IO Extortion Elevation Abduction