superior rectus
Also called SR, superior rectus muscle
The superior rectus is the vertical extraocular muscle on top of the globe, and its primary action is elevation, with intorsion and adduction as subsidiary actions.1 It arises from the upper part of the annulus of Zinn, runs forward at about 23 degrees to the visual axis, and inserts 7.7 mm behind the upper edge of the cornea.1
When the eye is turned outward by 23 degrees the muscle plane lines up with the visual axis and the superior rectus becomes a pure elevator, and that is the position used to test it.1,2 Its antagonist is the inferior rectus, and the superior division of the oculomotor nerve supplies it together with the levator of the upper lid.2,3
More detail
The subsidiary actions come from the muscle's angle: in primary position the superior rectus elevates, intorts and adducts, and if the eye could be turned inward by 67 degrees it would act only as an intorter.1,2 Its yoke in up-and-out gaze is the inferior oblique of the other eye. In a third nerve palsy loss of the superior rectus 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, with some listing intorsion before adduction and others giving the two without ranking.3,4
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