Levator palpebrae superioris muscle
|Levator muscle of upper eyelid|
Sagittal section of right orbital cavity.
|Insertion||Tarsal plate, upper eyelid|
|Artery||Ophthalmic artery, superior ophthalmic vein|
|Actions||Retracts / elevates eyelid|
|Antagonist||Orbicularis oculi muscle|
|Latin||Musculus levator palpebrae superioris|
|Anatomical terms of muscle|
The levator palpebrae superioris originates on the lesser wing of the sphenoid bone, just above the optic foramen. It broadens and decreases in thickness (becomes thinner) and becomes the levator aponeurosis. This portion inserts on the skin of the upper eyelid, as well as the superior tarsal plate. It is a skeletal muscle. The superior tarsal muscle, a smooth muscle, is attached to the levator palpebrae superioris, and inserts on the superior tarsal plate as well.
As with most of the muscles of the orbit, it is innervated by the superior division of the oculomotor nerve (Cranial Nerve III). It originates from a single central nucleus which provides innervation bilaterally to both LPS muscles. Due to this a single lesion in the central nucleus can cause bilateral ptosis. This is why, when one turns one's eye upward, the eyelid tends to rise with it. An adjoining smooth muscle, the superior tarsal muscle, is sympathetically innervated and is occasionally considered to be part of the levator palpebrae superioris.
The levator palpebrae superioris muscle elevates and retracts the upper eyelid.
Damage to this muscle, or its innervation, can cause ptosis, the drooping of the eyelid. Ptosis can also be caused by damage to the adjoining superior tarsal muscle, or its sympathetic innervation. Such damage to the sympathetic supply occurs in Horner's syndrome, and presents as a partial ptosis.
- "eye, human."Encyclopædia Britannica. 2008. Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 5 Apr. 2008