Superior rectus muscle

Last revised by Craig Hacking on 27 Dec 2021

Superior rectus muscle is one of the six extraocular muscles that control eye movements.

Superior rectus, along with the other rectus muscles, arises from the annulus of Zinn, the common tendinous ring at the apex of the orbit that surrounds the optic canal 1.

Superior rectus runs anteriorly over the superior surface of the eye and inserts into the superior surface of the sclera just posterior to the junction of cornea and sclera 2.

Superior rectus is closely related to levator palpebrae superioris, which runs parallel and immediately superior to it and is responsible for elevation of the eyelid.

Branches of the ophthalmic artery, itself a branch of the internal carotid artery.

Innervated by the oculomotor nerve, which also supplies medial rectus, inferior rectus, and inferior oblique muscles.

The primary action of the superior rectus is to elevate the eye (see figure 1) 1. However, because the apex of the orbit is placed medially in the skull, the orbital axis that the superior rectus runs in does not correspond with the optical axis of the eye in its neutral position. This means that the superior rectus has secondary actions of adduction and internal rotation (see figures 2 and 3).

If the eye is abducted by the lateral rectus such that the optical axis lines up with the orbital axis, the superior rectus produces ocular elevation only, and is solely responsible for this movement. Thus, when the physician testing eye movements first asks the patient to follow their finger laterally then superiorly in the familiar H-shape, the superior rectus muscle (and the oculomotor nerve that supplies it) are being directly tested.

If the eye is adducted by the medial rectus, the orbital axis runs almost perpendicular to the optical axis, so the superior rectus no longer produces effective ocular elevation, and instead produces internal rotation and adduction.

Rectus comes from the Latin rectos, meaning straight 1.

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