Eye Muscles Flashcards
Dilator Pupillae
Origin: radial fibers in iris
Insertion: blends with sphincter pupillae fibers
Innervation: sympathetic fibers from SCG
Blood Supply: ophthalmic artery
Action: dilates pupil
Sphincter Pupillae
Origin: circular smooth muscle of iris that passes around pupil
Insertion: blends with dilator pupillae fibers
Innervation: parasympathetic fibers via oculomotor nerve (CN III)
Blood Supply: ophthalmic artery
Action: constricts pupil
Ciliary
Origin: corneoscleral junction
Insertion: ciliary body
Innervation: parasympathetic fibers via short ciliary nerves (CN III)
Blood Supply: ophthalmic artery
Action: constricts ciliary body and lens rounds up (accommodation)
Medial Rectus
Origin: common tendinous ring
Insertion: medial aspect of eyeball, posterior to corneosceral junction
Innervation: oculomotor nerve
Blood Supply: ophthalmic artery
Action: adducts eyeball
Lateral Rectus
Origin: common tendinous ring
Insertion: lateral aspect of eyeball, posterior to corneosceral junction
Innervation: abducent nerve (CN VI)
Blood Supply: ophthalmic artery
Action: abducts eyeball
Superior Oblique
Origin: body of sphenoid (above optic foramen), medial to origin of superior rectus
Insertion: passes through trochlea, attaches to superior sclera between superior and lateral recti
Innervation: trochlear nerve (CN IV)
Blood Supply: ophthalmic artery
Action: abducts, depresses, and medially rotates eyeball
Inferior Oblique
Origin: anterior floor of orbit lateral to nasolacrimal canal
Insertion: lateral sclera deep to lateral rectus
Innervation: oculomotor nerve
Blood Supply: ophthalmic artery
Action: abducts, elevates, and laterally rotates eyeball
Superior Rectus
Origin: common tendinous ring
Insertion: superior aspect of eyeball, posterior to the corneosceral junction
Innervation: oculomotor nerve
Blood Supply: ophthalmic artery
Action: elevates, adducts, and medially rotates eyeball
Inferior Rectus
Origin: common tendinous ring
Insertion: inferior aspect of eyeball, posterior to corneoscleral junction
Innervation: oculomotor nerve
Blood Supply: ophthalmic artery
Action: depresses, adducts, and laterally rotates eyeball
Levator Palpebrae Superioris
Origin: lesser wing of sphenoid, anterior to optic canal
Insertion: superior tarsal plate
Innervation: oculomotor nerve
Blood Supply: ophthalmic artery
Action: raises upper eyelid
