Question

Which cranial nerves innervate only one eye muscle? Select all that apply. a) Oculomotor (III) nerve b) Trigeminal (V) nerve c) Abducens (VI) nerve

Answer 1

The trochlear (IV) and abducens (VI) cranial nerves each innervate one eye muscle responsible for specific movements of the eye. The oculomotor (III) nerve, however, controls multiple eye muscles and the trigeminal (V) nerve is not involved in eye muscle innervation.

Step-by-step explanation:

The cranial nerves that innervate only one eye muscle are the trochlear (IV) nerve, which controls the superior oblique muscle, and the abducens (VI) nerve, which controls the lateral rectus muscle. The oculomotor (III) nerve is not an answer choice since it innervates multiple eye muscles, not just one. The trigeminal (V) nerve is primarily responsible for facial sensation and mastication muscles, hence not involved in innervating any eye muscles. Therefore, the correct answer is the abducens (VI) nerve which innervates only the lateral rectus muscle.

Answer 2

The trochlear (IV) and abducens (VI) nerves each innervate only one eye muscle. The trochlear controls the superior oblique muscle, while the abducens controls the lateral rectus muscle.

Step-by-step explanation:

The cranial nerves that innervate only one eye muscle are the trochlear (IV) nerve and the abducens (VI) nerve. The trochlear nerve is responsible for controlling the superior oblique muscle, allowing the eye to rotate medially, or intorsion. The abducens nerve innervates the lateral rectus muscle, which causes the abduction of the eye. The oculomotor (III) nerve, in contrast, innervates multiple eye muscles, including all the other extraocular muscles as well as the levator palpebrae superioris muscle.