The superior rectus is the primary elevator of the abducted eye, arising from the orbital apex common tendinous ring with the other rectus muscles. Its anatomical association with the levator palpebrae superioris explains why ptosis frequently accompanies CN III palsy (which also supplies levator palpebrae). In upgaze the superior rectus and inferior oblique both elevate but through different mechanisms — superior rectus in abduction, inferior oblique in adduction.
| Origin | Common tendinous ring (annulus of Zinn) at the orbital apex around the optic canal |
|---|---|
| Insertion | Superior sclera 7.7 mm from the limbus |
| Nerve Supply | Superior division of the oculomotor nerve (CN III) |
| Blood Supply | Ophthalmic artery |
| Actions | Elevation (primary when the eye is abducted); Internal rotation (intorsion); Adduction |
|---|
The six extra-ocular muscles (four recti and two obliques) work in yoked pairs: superior rectus with contralateral inferior oblique for upgaze, and inferior rectus with contralateral superior oblique for downgaze. Understanding these pairs allows localisation of isolated extra-ocular muscle weakness.
Superior rectus palsy produces hypotropia (affected eye lower) that worsens in ipsilateral upgaze. It is less common than inferior oblique overaction as a cause of upgaze limitation. Superior rectus recession is performed to reduce its primary elevation power in superior rectus overaction or in dissociated vertical deviation (DVD).
Not directly palpable. Assessed by corneal light reflex and cover test in different gaze positions.
Eye elevation weakness producing hypotropia in ipsilateral upgaze managed with superior rectus recession or inferior rectus advancement.
