Lab 1 Sense Eye PDF

Sense organs 1 Eye Dr. Shereen Adel Professor of Anatomy & Embryology By the end of this lecture, you should be able to: 1- Describe bony orbit. 2- Identify contents of orbital cavity. 3- Describe origin, insertion, action & nerve supply of extra-ocular muscles. ...

Sense organs 1 Eye Dr. Shereen Adel Professor of Anatomy & Embryology By the end of this lecture, you should be able to: 1- Describe bony orbit. 2- Identify contents of orbital cavity. 3- Describe origin, insertion, action & nerve supply of extra-ocular muscles.  ORBITAL CAVITY A pyramidal space with a base, apex and four walls. Boundaries and Walls: Roof Orbital plate of frontal bone Floor Frontal 1.Orbital surface of maxilla bone 2.Zygomatic bone Medial wall Greater wing Lacrimal Ethmoid 1.Lacrimal bone of sphenoid bone bone 2.Orbital plate of ethmoid bone Maxillary Lateral wall bone 1.Zygomatic bone. 2.Greater wing of sphenoid bone. Contents of the Orbital Cavity Eyeball Muscles Vessels Nerves Ciliary ganglion Lacrimal gland Orbital fat Muscles of the Orbit Levator palpebrae suprioris Extrinsic muscles of the eye Intrinsic muscles of the eye 4 Recti muscles 2 Oblique muscle Dilator pupillae Superior rectus Superior oblique Constrictor pupillae Inferior rectus Inferior oblique Ciliary muscle Medial rectus Lateral rectus  II. extraocular Muscles Recti Muscles: (superior, inferior, medial, lateral) O: common tendinous ring I: sclera ant to coronal equator of eyeball A: direct the cornea vertically or horizontally according to their name Levator palp Levator palp Superior rectus superioris Superior oblique superioris Superior oblique Lateral rectus Med rectus Lateral rectus Inf. oblique Superior oblique O: junction of the roof with medial surface of the orbit I: its tendon passes through the trochlea, inserted into the sclera post to coronal equator A: depression, abduction and intorsion N.S. trochlear n. Inferior oblique O: anterior part of the floor of the orbit I: sclera post to coronal equator A: elevation, abduction and extorsion N. S. : inferior division of oculomotor n. Levator palpebrae superioris (LPS): Origin: from orbital surface roof antero-superior to optic canal Insertion: its flat tendon splits into lamella inserted into: i. Skin of upper eyelid. ii. Superior tarsus (this part is the strongest part & is formed of smooth involuntary muscles & called Müller’s muscle). iii. Superior fornix of conjunctiva Nerve Supply of extraocular muscles: (All by oculomotor except SO4, LR6) ▪ All the extraocular muscles are supplied by the oculomotor nerve except the superior oblique and lateral rectus where: a) SR and LPS are supplied by the superior division of oculomotor. b) MR, IR and IO by the inferior division of oculomotor ▪ SO: by trochlear nerve. ▪ LR: by abducent nerve  II. Intraocular Muscles Formed of smooth muscle fibers, Have involuntary actions Supplied by autonomic nerves (sympathetic and parasympathetic) Include 3 muscles: 3) Ciliaris 1) Constrictor pupillae (Parasympathetic) (Parasympathetic) Ciliary muscle contraction renders the lens of the eye more convex, thus accommodating for near vision. 2) Dilator pupillae (Sympathetic) Blood Vessels of the Orbit Supratrochlear a. Ophthalmic Artery A branch of the 4th part ICA Dorsal nasal a. Enters the orbit through the optic canal inferolateral to the optic nerve Crosses above the optic nerve from lateral to medial Runs along the medial wall of the orbit Terminates near the Ophthalmic a. medial end of the upper eyelid by dividing into: ICA 1.Supratrochlear artery 2.Dorsal nasal artery Branches of the Ophthalmic Artery Central artery of the retina: Lacrimal artery: Supraorbital artery forehead Posterior ethmoidal artery Supplies post ethmoidal sinus and nasal branches Anterior ethmoidal artery Supplies middle and anterior ethmoidal sinuses. Gives nasal branches. Branches of the Ophthalmic Artery Medial palpebral artery, to medial parts of eyelids Supratrochlear artery, forehead Dorsal nasal artery anastomoses with the termination of facial (angular) artery Post ciliary arteries Muscular arteries  Ophthalmic Veins Superior ophthalmic vein: Receives tributaries corresponding to branches of the ophthalmic artery. Passes through the superior orbital fissure to end in the cavernous sinus Superior ophthalmic vein Facial vein Cavernous sinus -It communicates anteriorly with the supraorbital and angular veins Inferior Pterygoid plexus ophthalmic vein of veins  Ophthalmic Veins Inferior ophthalmic vein: Begins at the anterior part of the floor of the orbit and runs backwards Passes through the sup orbital fissure and ends in the cavernous sinus Superior Facial ophthalmic vein vein -It communicates with Cavernous pterygoid plexus of sinus veins by a small vein passing through inferior orbital fissure. Inferior Pterygoid plexus ophthalmic vein of veins On the provided diagrams identify the following: - 7 Extra ocular muscles. - Ophthalmic artery - Optic nerve