Medial rectus

The medial rectus (also medial rectus muscle, medial rectus extraocular muscle, latin: musculus rectus medialis) is one of the six extra-ocular muscles that are in control of eye movements. The medial rectus is responsible for turning the visual gaze medially.

Origin

The medial rectus originates from the medial part of the common tendinous ring, and also from the dural sheath of the optic nerve. It passes horizontally forwards along the medial wall of the orbit, below superior oblique.

Insertion

The medial rectus inserts into the medial surface of the sclera, approximately 5.5 mm from the limbus and slightly anterior to the other recti muscles.

Action

Contraction of the medial rectus turns the eyeball medially. The right and left medial recti acting together are responsible for convergence of the eyes

Innervation

The medial rectus is innervated by the oculomotor nerve (CN III).

Blood supply

The medial rectus receives blood supply from the ophthalmic artery.