Which cranial nerve is responsible for lateral eye movements (look to the right and left)?

• A. Abducens
• B. Oculomotor
• C. Trochlear
• D. Optic

Answer: (A)

The ability to move the eye outward, to look to the right or left, is produced by the lateral rectus muscle. That muscle is innervated by the abducens nerve, so this nerve is responsible for lateral eye movements. If the abducens is functioning, the eye can abduct (move away from the midline) when you look to either side.

In contrast, the oculomotor nerve controls several other eye muscles, including the medial rectus which moves the eye inward toward the nose, as well as lifting the eyelid and constricting the pupil. The trochlear nerve mainly controls the superior oblique, which helps with intorsion and depression when the eye is adducted. The optic nerve is involved in vision in general, not motor movement of the eye muscles.

So, the nerve that enables looking to the right and left by abducting the eye is the abducens nerve.