The superior rectus is an eye muscle, controlling the eye as it moves up. This muscle is among four muscles — including the medial rectus, lateral rectus, and the inferior rectus — which control the eye's movement.
When the eye is turned away from the nose, both the superior and inferior rectus muscles work together to raise and push the eye upward. When the eye is turned inward, those same two muscles work to raise and push the eye in. When a person looks straight ahead, all four muscles work together to stabilize the eye, with about half of the work performed by the superior and inferior rectus muscles.
Doctors test the eye's movement and detect problems with the superior rectus by asking the patient to follow a finger with the eyes. The doctor often draws the letter H in the air, because the two parallel lines in the H test the superior rectus and the inferior rectus. The vertical line in the center of the H checks the movements of the lateral rectus and medial rectus.