How many eye muscles are activated by the oculomotor nucleus?

How many eye muscles are activated by the oculomotor nucleus?

• A. 2
• B. 3
• C. 4
• D. 6

Answer: (C)

Four eye muscles are driven by the oculomotor nucleus. The oculomotor nerve innervates four extraocular muscles that move the eyeball: the medial rectus, superior rectus, inferior rectus, and inferior oblique. It also sends fibers to the levator palpebrae superioris, which raises the eyelid, but that muscle does not move the eye itself. Since the question refers to muscles that move the eye, the correct count is four. (The superior oblique is controlled by the trochlear nerve, and the lateral rectus by the abducens nerve.)

Four eye muscles are driven by the oculomotor nucleus. The oculomotor nerve innervates four extraocular muscles that move the eyeball: the medial rectus, superior rectus, inferior rectus, and inferior oblique. It also sends fibers to the levator palpebrae superioris, which raises the eyelid, but that muscle does not move the eye itself. Since the question refers to muscles that move the eye, the correct count is four. (The superior oblique is controlled by the trochlear nerve, and the lateral rectus by the abducens nerve.)