The structure indicated is the levator palpebrae superioris muscle.

The levator palpebrae superioris muscle is located in the upper eyelid and is responsible for raising the eyelid. Just like the rectus muscles, and oblique muscles of the eyeball, the levator palpebrae superioris muscle is innervated by the oculomotor nerve (cranial nerve III).

The eyelids themselves are supported by the tarsus – in the upper eyelid the superior tarsus, and in the lower eyelid, the inferior tarsus. These structures consist of dense connective tissue.

Origin: Roof of the orbit on sphenoid bone, above the optic foramen

Insertion: Anterior surface of superior tarsus and upper eyelid

Innervation: Oculomotor nerve (cranial nerve III)

Action: retraction and elevation of eyelid.