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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.
The initial clinical examination of the extraoccular eye muscles is done by examining the movement of the globe of the eye through the six cardinal eye movements. When the eye is turned out (temporally) and horizontally, the function of the lateral rectus muscle is tested.
Horizontal movement is controlled entirely by the medial and lateral recti muscles; the medial rectus muscle is responsible for adduction, the lateral rectus muscle for abduction. Vertical movement requires the coordinated action of the superior and inferior recti muscles, as well as the oblique muscles.
These changes serve to reduce the variation in the misalignment of the two eyes in different gaze positions (incomitance). Where this process has fully developed, the preferred option is a simple recession, or weakening, of the medial rectus of the affected eye, combined with a resection, or strengthening, of the lateral rectus of the same eye.
The abducens nucleus contains two types of cells: motor neurons that control the lateral rectus muscle on the same side, and interneurons that cross the midline and connect to the contralateral oculomotor nucleus (which controls the medial rectus muscle of the opposite eye). In normal vision, lateral movement of one eye (lateral rectus muscle ...
The movement of the eye is controlled by six distinct extraocular muscles, a superior, an inferior, a medial and a lateral rectus, as well as a superior and an inferior oblique. The superior ophthalmic vein is a sigmoidal vessel along the superior margin of the orbital canal that drains deoxygenated blood from surrounding musculature.
The main muscle for abduction is the lateral rectus, so although superior oblique contributes to a downwards and lateral eye movement, testing this motion would not be specific enough as inferior and lateral recti muscles would also be tested.
The three nerves that control the extraocular muscles are the oculomotor, trochlear, and abducens nerves, which are the third, fourth, and sixth cranial nerves. the abducens nerve is responsible for abducting the eye, which it controls through contraction of the lateral rectus muscle.