Trochlear nucleus corresponds to which cranial nerve number?

Trochlear nucleus corresponds to which cranial nerve number?

• A. CN II
• B. CN III
• C. CN IV
• D. CN V

Answer: (C)

The main idea is that each cranial nerve has a specific numbered designation, and the nucleus named for that nerve is the motor center that gives rise to its fibers. The trochlear nucleus is the motor nucleus for the nerve that innervates the superior oblique muscle, which is the trochlear nerve. That nerve is numbered four in the cranial nerve sequence, so the trochlear nucleus corresponds to cranial nerve number four. The other options map to different functions: the optic nerve handles vision, the oculomotor nerve supplies most extraocular muscles and pupil control, and the trigeminal nerve handles facial sensation and mastication.

The main idea is that each cranial nerve has a specific numbered designation, and the nucleus named for that nerve is the motor center that gives rise to its fibers. The trochlear nucleus is the motor nucleus for the nerve that innervates the superior oblique muscle, which is the trochlear nerve. That nerve is numbered four in the cranial nerve sequence, so the trochlear nucleus corresponds to cranial nerve number four. The other options map to different functions: the optic nerve handles vision, the oculomotor nerve supplies most extraocular muscles and pupil control, and the trigeminal nerve handles facial sensation and mastication.