Which nerve innervates eye movement outward (lateral)?

• A. Abducens (CN VI)
• B. Oculomotor (CN III)
• C. Trochlear (CN IV)
• D. Trigeminal (CN V)

Answer: (A)

The outward movement of the eye, or abduction, is produced by the lateral rectus muscle. That muscle is supplied by the abducens nerve (cranial nerve VI), so this nerve is responsible for eye movement away from the midline.

The oculomotor nerve (cranial nerve III) controls most of the other extraocular muscles (up, down, and medial movement, plus some eye rotations), but not the lateral rectus. The trochlear nerve (cranial nerve IV) innervates the superior oblique, which mainly depresses and intorts the eye when it’s turned inward. The trigeminal nerve (cranial nerve V) is not involved in innervation of the extraocular muscles.