[1][2] The levator palpebrae superioris originates from inferior surface of the lesser wing of the sphenoid bone, just above the optic foramen.

The levator palpebrae superioris receives motor innervation from the superior division of the oculomotor nerve.

[4][5] Lesions in CN III can cause ptosis,[5] because without stimulation from the oculomotor nerve the levator palpebrae cannot oppose the force of gravity, and the eyelid droops.

Ptosis can also result from 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.