Dr. Mohamed Elfiky

1. Head and Neck
The Orbit
Prof. Dr. Mohamed El fiky
Professor of Anatomy and embryology

2. Extra-ocular Muscles
1-Levator palpebrae
superioris
2-Superior rectus.
3-Lateral rectus.
4-Inferior rectus.
5-Medial rectus.
6-Superior oblique .
7-Inferior oblique .

3. Levator Palpabrae Superioris
1- Levator Palpabrae Superioris
.
Origin: From the roof of the
orbit in front of the optic canal
insertion: Forms three lamellae
which are inserted into :
(1) The skin of the
upper eyelid.
(2) The superior
tarsus.
(3) Superior fornix of
the conjunctiva.
Nerve supply: Oculomotor
nerve.
Actions: Elevation of the upper
eyelid.

4. Ptosis

5. Superior Rectus
Lateral Rectus
Inferior Rectus
Medial Rectus
Four Recti
Superior, Inferior, Medial and Lateral
Annulus Ring of Zinn
Origin: From the common tendinous ring ( ring of Zinn) which surrounds the optic canal
Insertion: The recti are inserted into the sclera in front of the equator of the eyeball. The
average distances from the cornea are:
(a) Superior rectus: 7.7 mm.
(b) (b) Lateral rectus: 6.9 mm.
(c) Inferior rectus: 6.5 mm.
(d) Medial rectus: 5.5 mm.

6. Superior Oblique
Inferior Oblique
The Two Oblique Muscles
Superior and Inferior Oblique
Superior oblique
Origin: From the body of sphenoid superomedial to the optic foramen.
Insertion: Passes forwards along the medial wall of the orbit.
Ends in a slender tendon, which passes through a fibrocartilaginous bully
(trochlea) attached to the trochlear fossa of the frontal bone.
The tendon then passes downwards, backwards and laterally to be inserted into
the lateral surface of the sclera behind the equator.
Inferior oblique
Origin : From the floor of the orbit
lateral to the lacrimal notch.
Insertion:
Passes laterally below the inferior
rectus and then deep to the lateral
Inserted into the lateral surface of
the sclera behind the equator.

7. Nerve Supply of the Extra-ocular Muscles
(SO4 LR6)3
Note: All the extrinsic muscles of the eyeball are supplied by the oculomotor nerve except:
(1) Lateral rectus: by the abducent.
(2) Superior oblique: by the trochlear. (SO4 LR6)
3
Action of the Extra-ocular Muscles
(1)Levator palpebrae suprioris : Elevation of the upper eyelid.
(2) Superior rectus: (a) Elevation; (b) Adduction; (c) Intortion.
(3) Inferior rectus: (a) Depression; (b) Adduction; (c) Extorsion
(4) Medial rectus: Adduction.
(5) Lateral rectus: Abduction
(6) Superior oblique: (a) Depression; (b) Abduction; (c) Intortion.
(7) Inferior oblique: (a)Elevation; (b) Abduction; (c) Extorsion.

8. 12 o’clock
Superior Rectus
Inferior Rectus
Superior Oblique
Inferior Oblique
Medial Rectus
Lateral Rectus
The Primary Position

9. Superior RectusInferior RectusSuperior ObliqueInferior Oblique
Medial Rectus
Lateral Rectus
The Primary Position
12 o’clock
Actions of the Extra-ocular
Muscles

11. Squint

12. 1- Ophthalmic Artery
Origin: It is a branch of the internal carotid artery
Course and relations: Enters the orbit through the optic canal.
Branches:
(1) Central artery of the retina: most important branch, it pierces the optic nerve and runs through it
to reach the retina.
(2) Lacrimal artery: to the lacrimal gland.
(3) Muscular branches: to the orbital muscles.
(4) Long and short posterior ciliary arteries: supply the eyeball.
(5) Anterior and posterior ethmoidal arteries: accompany the anterior and
terior ethmoidal nerves.
(6) Supraorbital: accompanies the corresponding nerve to the scalp
(7) Supratrochlear : one of the two terminal branches, accompanies the upratrochlear nerve.
(8) Dorsal nasal: is the other terminal branch, passes below the trochlea to supply the nose

13. Internal Carotid Artery
Ophthalmic Artery
Optic Canal
Optic Nerve
8-Supratrochlear Artery (terminal branch)7-Dorsal Nasal Artery
(terminal branch)
1- Ophthalmic Artery
4-Supra orbital
2- Lacrimal Artery
3- Posterior Ciliary Arteries
6- Anterior Ethmoidal Artery
5- Posterior Ethmoidal Artery
1- Central Artery of the retina

14. 1- Ophthalmic Artery

15. Superior Ophthalmic Vein
Inferior Ophthalmic Vein
Pterygoid Plexus of Veins
Anterior Facial Vein
2- Ophthalmic Veins

16. Nerves of the orbit
(1) Optic nerve: it is the 1st cranial nerve . It pass through the optiv canal and
it the nerve of vision .
(2) Oculomotor nerve :
§ Comes out of the midbrain .
§ Enters the cavernous sinus
§ Divides in the anterior part of the sinus into superior and inferior divisions,
Distribution :
(1) The superior division: supplies 2 muscles:
(a) Superior rectus. (b) Levator palpebrae superioris.
(2) The inferior division : supplies 3 muscles:
(a) Medial rectus. (b) Inferior rectus. (c) Inferior obique.
(3) Motor root to the Ciliary ganglion: Carries parasympathetic fibers to
supply 2 intraocular muscles:
(a) Ciliary muscle: for accoummodation.
(b) Sphincter pupillae muscle : constricts the pupil.

17. Trochlear nerve :
Origin : from the midbrain at the level of the inferior colliculus.
• Course : Enters the cavernous and inter the orbit through
sup orbital fissure
• Distribution : Supplies the superior oblique muscle.
Abducent nerve :
Origin : from the pons
Course :Runs forwards in the floor of the cavernous sinus
Enters the orbit through the superior orbital fissure.
Distributions : Supplies the lateral rectus muscle through
its ocular surface.

19. (5) Ophthalmic division of trigeminal
Origin : From the convex anterior margin of the trigeminal ganglion.
Course:
· runs forwards in the lateral wall of the cavernous sinus
· Divides in the sinus into 3 branches
Branches :
(A) Frontal. (B) Lacrimal. (C) Nasociliary
The three branches enter the orbit through the superior orbital fissure.
Frontal nerve
Branches:
(1) Supratrochlear nerve:
(2) Supraorbital nerve:
Lacrimal nerve
Branches:
· Glandular branches : to the lacrimal gland (sensory).
· Palpebral branch : to the skin of upper eyelid.

20. Nasociliary nerve
Branches :
(1) Communicating branch to the ciliary ganglion;
(2) Two or three long ciliary nerves : Contains sympathetic fibers for the dilator pubillae
(3) Posterior ethmoidal nerve:
(4) Infratrochlear:
(5) Anterior ethmoidal nerve :

21. Ciliary ganglion
Site : Between the optic nerve and the tendon of the lateral rectus muscle .
Roots:
(1) Parasympathetic (Motor): from the nerve to inferior oblique (branch of
oculomotor). It relays in the ganglion.
(2) Sensory root: comes from the nasociliary nerve. It contains sensory fibers front the
eyeball. The fibers do not relay in the ganglion,
(3) Sympathetic root: is a branch from the sympathetic plexus, around the internal
carotid (passes without relay).
Branches: Short ciliary nerves :
(a) Sensory fibers: from the eyeball.
(b) Sympathetic fibers: for the blood vessels of' the eyeball.
(c) Parasympathetic postaganglionic fibers: to the sphincter pupillae and ciliary
mucles.

22. Ciliary ganglion

23. Thank You