Inferior rectus

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Inferior rectus

The inferior rectus muscle, is shown in this superior view of the eye, along with its axis of rotation. The other muscle is the superior oblique muscle, which angles around the trochlea.
Latin	musculus rectus inferior bulbi
Gray's	subject #227 1022
Origin	annulus of Zinn at the orbital apex
Insertion	6.5 mm inferior to the limbus
Artery
Nerve	inferior branch of oculomotor nerve
Actions	depression and adduction

The inferior rectus muscle is a muscle in the orbit.

1 Actions
2 Innervation
3 Additional images
4 References
5 External links

Actions

It depresses, adducts, and helps extort (rotate laterally) the eye.

The inferior rectus muscle is the only muscle that is capable of depressing the pupil when it is in a fully abducted position.^[1]

Innervation

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

Additional images

Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.
The right eye in sagittal section, showing the fascia bulbi (semidiagrammatic).
Inferior rectus muscle
Inferior rectus muscle
Extrinsic eye muscle. Nerves of orbita. Deep dissection.
Extrinsic eye muscle. Nerves of orbita. Deep dissection.
Extrinsic eye muscle. Nerves of orbita. Deep dissection.
Extrinsic eye muscle. Nerves of orbita. Deep dissection.