Final answer:
The RLN innervates the muscles of the neck, including the sternocleidomastoid and trapezius muscles, and is responsible for controlling head and neck movements.
Step-by-step explanation:
The RLN (recurrent laryngeal nerve) innervates the muscles of the neck, specifically the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is responsible for head flexion and rotation, while the trapezius muscle can cause neck extension and hyperextension. The RLN plays a crucial role in controlling the movement of the head and neck.