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either member of the sixth pair of cranial nerves. The abducens nerve originates in a motor nucleus in the pons on the floor of the rhomboid fossa. The outgrowths of the cells of this nucleus emerge from the brain at a point that lies between the pons and the pyramid of the medulla oblongata. Forming a single nerve trunk, the outgrowths exit from the cranial cavity through the superior orbital fissure and innervate the lateral rectus muscle of the eye, which turns the eyeball outward.
Lesions of the abducens nerve interfere with the mobility of the eyeball and can result in anomalies of the eyeball’s orientation. The latter condition is known as esotropia. Dizziness, double vision, and constrained head movements can also arise as a result of injury to the abducens nerve.