Which nucleus coordinates the abduction of the eye?

• A. Oculomotor nucleus
• B. Trochlear nucleus
• C. Abducens nucleus
• D. Facial nucleus

Answer: (C)

Abduction of the eye is driven by the lateral rectus muscle, which pulls the eye outward away from the midline. The nucleus that serves this muscle is located in the pons and sends its output via the abducens nerve to the lateral rectus. This nucleus also helps coordinate horizontal eye movements by interfacing with the oculomotor system to ensure both eyes move together. The oculomotor nucleus controls muscles that move the eye medially and lift or depress the eye, the trochlear nucleus controls the superior oblique, which intorts and depresses, and the facial nucleus handles facial muscles. So the nucleus dedicated to the lateral rectus—and thus to abduction—is the abducens nucleus.