superior rectus
Also called SR, superior rectus muscle
The vertical extraocular muscle on top of the globe. It arises from the upper part of the annulus of Zinn, runs forward at about 23 degrees to the visual axis, inserts 7.7 mm behind the upper edge of the cornea, and its primary action is elevation, with intorsion and adduction as subsidiary actions1.
When the eye is turned outward by 23 degrees the muscle plane lines up with the visual axis and the muscle becomes a pure elevator; that is the position used to test it1,2. Its antagonist is the inferior rectus, and the superior division of the oculomotor nerve supplies it together with the levator of the upper lid2,3.
More detail
The subsidiary actions come from the muscle's angle: in primary position it elevates, intorts and adducts, and if the eye could be turned inward by 67 degrees it would act only as an intorter1,2. Its yoke in up-and-out gaze is the inferior oblique of the other eye. In a third nerve palsy its loss limits elevation, and in the head tilt test it is the muscle that lifts the eye when the superior oblique is weak. Texts rank the subsidiary actions differently: some list intorsion before adduction, others give the two without ranking3,4.
Sources (4)
- Kanski, Clinical Ophthalmology (2024), ch. 18
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 3 and ch. 4
- Adler's Physiology of the Eye, ch. 7, Table 7.1
- Pickwell's Binocular Vision Anomalies, ch. 17
Reviewed October 2026