The lateral rectus muscle is a muscle on the lateral side of the eye in the orbit. It is one of six extraocular muscles that control the movements of the eye. The lateral rectus muscle is responsible for lateral movement of the eyeball, specifically abduction. Abduction describes the movement of the eye away from the midline (i.a. nose), allowing the eyeball to move horizontally in the lateral direction, bringing the pupil away from the midline of the body.

Structure

The lateral rectus muscle originates at the lateral part of the common tendinous ring, also known as the annular tendon. The common tendinous ring is a tendinous ring that surrounds the optic nerve and serves as the origin for five of the seven extraocular muscles, excluding the inferior oblique muscle.

The lateral rectus muscle inserts into the temporal side of the eyeball. This insertion is 6.9 mm from the corneal limbus. Proper function of the lateral rectus is tested clinically by asking the patient to look laterally. Depending on the underlying cause of the lateral rectus palsy, some improvement may occur naturally over time. While the prognosis for a lateral rectus palsy onset by a viral illness is generally positive, the prognosis for an onset of trauma or tumor is quite poor. Ultimately, nerves are not very good at regenerating or healing themselves, so if the damage is severe there will be permanent damage.

In addition, another disorder associated with the lateral rectus muscle is Duane Syndrome. This syndrome occurs when the sixth cranial nerve which controls the lateral rectus muscle does not develop properly. It is believed that Duane Syndrome is a result of a disturbance of normal embryonic development due to a genetic or an environmental factor.

Additional images

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File:Trochlear and frontal nerves.jpg|Lateral rectus muscle

File:Gray890.png|Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.

File:Lateral orbit nerves.jpg|Lateral view of the eyeball with lateral rectus muscle visible (cut).

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See also

  • Extraocular muscles

References

de:Augenmuskeln#Musculus rectus lateralis