Muscles of the Orbit Flashcards
Levator Palpebrae Superioris Action
Elevates the upper eyelid
Levator Palpebrae Superioris Origin and Insertion
Origin:
Lesser wing of the sphenoit (anterior and superior to the optic canal)
Insertion:
Tarsal plate and skin of the upper eyelid
Levator Palpebrae Superioris nerve supply
Oculomotor Nerve CN III
-Some deep layer supplied by sympathetic nerves (open eye)
Levator Palpebrae Superioris extra info
Thin flat muscle
Rectus Muscles nerve supply
Superior, inferior and medial: Oculomotor Nerve CN III
Lateral: Abducent Nerve CN VI
Superior Rectus Muscle Action
Elevates, adducts, and laterally rotates the eye
Superior Rectus Muscle Origin and Insertion
Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF
Insertion:
Sclera just posterior to the cornea
Superior Rectus Muscle extra info
The pull of superior and inferior rectus is not parallel to the long axis of the eyeball hence adduction
Inferior Rectus Muscle Action
Depresses, adducts, and laterally rotates the eye
Inferior Rectus Muscle Origin and Insertion
Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF
Insertion:
Sclera just posterior to the cornea
Medial Rectus Muscle Action
Adducts the eyeball
Medial Rectus Muscle Origin and Insertion
Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF
Insertion:
Sclera just posterior to the cornea
Lateral Rectus Muscle Action
Abducts the eyeball
Lateral Rectus Muscle Origin and Insertion
Origin:
Common tendinous ring
Fibrous cuff
Surrounds the optic canal and medial part of SOF
Insertion:
Sclera just posterior to the cornea
Superior Oblique Action
Abducts, depresses, and medially rotates the eyeball
Superior Oblique Origin and Insertion
Origin:
Body of the sphenoid
Insertion:
Sclera, deep to superior rectus muscle
Superior Oblique nerve supply
Trochlea Nerve CN IV
Superior Oblique extra info
Its tendon passes through a fibrous ring (trochlea) lined with a synovial sheath allows easy slide, causes it to change direction
Inferior Oblique Action
Abducts, elevates, and laterally rotates the eye
Inferior Oblique Origin and Insertion
Origin:
Anterior part of the floor of the orbit
Insertion:
Sclera deep to the lateral rectus muscle
Inferior Oblique nerve supply
Oculomotor Nerve CN III
