External Cranium Face - Orbital Muscles Flashcards
Levator Palpebrae Superiors Origin
Lesser wing of sphenoid bone, superior and anterior to optic canal
Levator Palpebrae Superiors Insertion
Superior tarsus and skin of superior eyelid
Levator Palpebrae Superiors Innervation
Oculomotor nerve (CN III); deep layer (superior tarsal muscle) is supplied by sympathetic fibers
Levator Palpebrae Superiors Action
Elevates superior eyelid
Superior Rectus (SR) Origin
Common tendinous ring
Superior Rectus (SR) Insertion
Sclera just posterior to corneoscleral junction
Superior Rectus (SR) Innervation
Oculomotor nerve (CN III)
Superior Rectus (SR) Action
Elevates, adducts and rotates eyeball medially
Medial Rectus (MR) Origin
Common tendinous ring
Medial Rectus (MR) Insertion
Sclera just posterior to corneoscleral junction
Medial Rectus (MR) Innervation
Oculomotor nerve (CN III)
Medial Rectus (MR) Action
Adducts eyeball
Lateral Rectus (LR) Origin
Common tendinous ring
Lateral Rectus (LR) Insertion
Sclera just posterior to corneoscleral junction
Lateral Rectus (LR) Innervation
Abducent nerve (CN VI)
Lateral Rectus (LR) Action
Abducts eyeball
Inferior Rectus (IR) Origin
Common tendinous ring
Inferior Rectus (IR) Insertion
Sclera just posterior to corneoscleral junction
Inferior Rectus (IR) Innervation
Oculomotor nerve (CN III)
Inferior Rectus (IR) Action
Depresses, adducts, and rotates eyeball laterally
Superior Oblique (SO) Origin
Body of sphenoid bone
Superior Oblique (SO) Insertion
Its tendon passes through a fibrous ring or trochlea, changes its direction, and inserts into sclera deep to superior rectus muscle
Superior Oblique (SO) Innervation
Trochlear nerve (CN IV)
Superior Oblique (SO) Action
Abducts, depresses, and medially rotates eyeball
Inferior Oblique (IO) Origin
Anterior part of floor of orbit
Inferior Oblique (IO) Insertion
Sclera deep to lateral rectus muscle
Inferior Oblique (IO) Innervation
Oculomotor nerve (CN III)
Inferior Oblique (IO) Action
Abducts, elevates, and laterally rotates eyeball
