inferior rectus muscle

The inferior rectus muscle is a muscle in the orbit.

The inferior oblique and inferior rectus muscles keep the other eye level.

The two obliques prevent the eye from rotating about its long axis (retina to pupil) when the superior and inferior rectus muscles contract.

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

This polypoid mass consists of herniated orbital contents, periorbital fat and inferior rectus muscle.

This posterior medial angle causes the eye to roll with contraction of either the superior rectus or inferior rectus muscles.

For example, fractures of the orbital floor or medial orbital wall of the eye can entrap the medial rectus or inferior rectus muscles.

The inferior rectus muscle is the most commonly affected muscle and patient may experience vertical diplopia on upgaze and limitation of elevation of the eyes due to fibrosis of the muscle.

This is because as the eye is abducted (looks laterally), the contribution made by superior oblique to depression of the eye decreases, as the inferior rectus muscle causes this movement more directly and powerfully.

In Graves ophthalmopathy, it is not uncommon to see an esotropia (due to pathology of the medial rectus muscle) co-morbid with a hypotropia (due to pathology of the inferior rectus muscle).

MRI may be helpful in the diagnosis, in one study volumes of medial rectus, lateral rectus, and inferior rectus muscles in CPEO were not smaller than normal (in contrast to the profound atrophy typical of neurogenic paralysis).