Final answer:
The dorsal scapular nerve is a branch of the brachial plexus that innervates the rhomboid and levator scapulae muscles, providing movement and stability to the scapula.
Step-by-step explanation:
The dorsal scapular nerve is one of the supraclavicular branches of the brachial plexus. It arises from the fifth cervical spinal nerve and innervates the rhomboid muscles and levator scapulae muscles in the back. The dorsal scapular nerve controls the movement and stability of the scapula, allowing for proper shoulder mechanics during upper limb activities.