(4) Anatomy of the orbit.pdf

Head and Neck The Orbit Prof. Dr. Mohamed El fiky Professor of Anatomy and embryology fterelds Extra-ocular Muscles eyelid actonupper 1-Levator palpebrae superioris elevateuppereyelid 2-Superior rectus. 3-Lateral rectus. 4-Inferior rectus. 5-Medial rectus. 6-Superior oblique. 7-Inferior oblique. act...

Head and Neck The Orbit Prof. Dr. Mohamed El fiky Professor of Anatomy and embryology fterelds Extra-ocular Muscles eyelid actonupper 1-Levator palpebrae superioris elevateuppereyelid 2-Superior rectus. 3-Lateral rectus. 4-Inferior rectus. 5-Medial rectus. 6-Superior oblique. 7-Inferior oblique. actoneyebone MOHAMED EL FIKY 1- Levator Palpabrae Superioris. node ML 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.f Nerve supply: Oculomotor nerve. sympathetic Actions: Elevation of the upper fee FEET theft eyelid. 2part superficial part deeppart calledmolars muscletakenervesupplyfromsympatheticnervetrunk ifthereis a lesioninsympatheticnervetrunkwillleadtopartialptosis MOHAMED EL FIKY Levator Palpabrae Superioris Paralysis of levatorpalpabraesuperioris leading to ptosis dropeyelid Ptosis maybecome Four Recti Superior, Inferior, Medial and Lateral tree 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. 551sec Superior Rectus Annulus Ring of Zinn Medial Rectus Lateral Rectus Inferior Rectus MOHAMED EL FIKY The Two Oblique Muscles Superior and Inferior Oblique eerie 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. 5Mar e Store__In Int 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. Superior Oblique S Is Inferior Oblique MOHAMED EL FIKY Its Nerve Supply of the Extra-ocular Muscles RNIIte (SO4 LR6)3 fortherestextraocularmuscles Note: All the extrinsic muscles of the eyeball are supplied by the oculomotor nerve except: (1) Lateral rectus: by the abducent. kid pr (2) Superior oblique: by the trochlear. (SO4 LR6) 3 eur Action of the Extra-ocular Muscles (1)Levator palpebrae suprioris : Elevation of the upper eyelid. (2) Superior rectus: (a) Elevation; (3) Inferior rectus: (a) Depression; (4) Medial rectus: Adduction. (5) Lateral rectus: Abduction (6) Superior oblique: (a) Depression; (7) Inferior oblique: (a)Elevation; (b) Adduction; (b) Adduction; (b) Abduction; (b) Abduction; satient withsquintordeviationmediallysothemusclethatwillbeparalyzedis atientwithsquintordeviationlaterallysothemusclethatwillbeparalyzedis lateralrectus medialrectus (c) Intortion. (c) Extorsion (c) Intortion. (c) Extorsion. MOHAMED EL FIKY Inferior Rectus Lateral Rectus The Primary Position Superior Rectus Inferior Oblique Superior Oblique Medial Rectus 12 o’clock Medial Rectus Inferior Oblique e d 12 o’clock Superior Oblique Inferior Rectus Superior Rectus The__ s The Primary Position Lateral Rectus Actions of the Extra-ocular Muscles MOHAMED EL FIKY Squint in Transit lateralrectusmuscle thenervethataffect is abducent analysisof superior lateral inferior medial rectusand superior inferior oblique eadingto squint deviation ofeyebone maybecome MOHAMED EL FIKY 1- Ophthalmic Artery Origin: It is a branch of the internal carotid artery 5STif Jan Course and relations: Enters the orbit through the optic canal. 1 Branches: 1 thepatientcomplainofsudden blindnessthearterywilleffectedis centralartery oftheretina (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 MOHAMED EL FIKY 1- Ophthalmic Artery 7-Dorsal Nasal Artery (terminal branch) 8-Supratrochlear Artery (terminal branch) 4-Supra orbital 2- Lacrimal Artery 6- Anterior Ethmoidal Artery 5- Posterior Ethmoidal Artery Optic Nerve Ophthalmic Artery 3- Posterior Ciliary Arteries 1- Central Artery of the retina Internal Carotid Artery Optic Canal MOHAMED EL FIKY 1- Ophthalmic Artery MOHAMED EL FIKY 2- Ophthalmic Veins Superior Ophthalmic Vein Inferior Ophthalmic Vein Anterior Facial Vein Pterygoid Plexus of Veins MOHAMED EL FIKY 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. the cavernous sinus  Enters  Divides in the anterior part of the sinus into superior and inferior divisions, Distribution : Feeder e (1) The superior division: supplies 2 muscles: (a) Superior rectus. (b) Levator palpebrae superioris. (2) The inferior division : supplies 3 muscles: seed (a) Medial rectus. (b) Inferior rectus. (c) Inferior obique. affestTify (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. MOHAMED EL FIKY 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. MOHAMED EL FIKY MOHAMED EL FIKY (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 e Branches : (A) Frontal. (B) Lacrimal. (C) Nasociliary The three branches enter the orbit through the superior orbital fissure. 17g TafsirFrontal 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. MOHAMED EL FIKY 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 : MOHAMED EL FIKY 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. MOHAMED EL FIKY Ciliary ganglion MOHAMED EL FIKY Thank You