Final answer:
The trochlear nerve (CN IV) is a motor cranial nerve that innervates the superior oblique muscle and is involved in coordinating eye movements.
Step-by-step explanation:
The trochlear nerve (CN IV) is a motor cranial nerve. It innervates the superior oblique muscle, which is responsible for downward and inward rotation of the eye. The trochlear nerve is involved in coordinating eye movements.