Medial rectus muscle

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Medial rectus
Eyemuscles.png
Rectus muscles:
2 = superior, 3 = inferior, 4 = medial, 5 = lateral
Oblique muscles: 6 = superior, 8 = inferior
Other muscle: 9 = levator palpebrae superioris
Other structures: 1 = Annulus of Zinn, 7 = Trochlea, 10 = Superior tarsus, 11 = Sclera, 12 = Optic nerve
Gray785.png
Figure showing the mode of innervation of the Recti medialis and lateralis of the eye.
Latin musculus rectus medialis bulbi
Gray's p.1022
Origin annulus of Zinn at the orbital apex
Insertion 5.5 mm medial to the limbus
Nerve inferior division of the oculomotor nerve
Actions adducts the eyeball (makes it move inwards)
Anatomical terms of muscle

The medial rectus muscle is a muscle in the orbit.

As with most of the muscles of the orbit, it is innervated by the inferior division of the oculomotor nerve (Cranial Nerve III).

This muscle shares an origin with several other extrinsic eye muscles, the anulus tendineus, or common tendon.

It is the largest of the extraocular muscles and its only action is adduction of the eyeball. Its function is to bring the pupil closer to the midline of the body. It is tested clinically by asking the patient to look medially.

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