Which nerve supplies the side of the arm and back of the hand?

The radian nerve is responsible for supplying the side of the arm and the back of the hand, making it the correct choice. It facilitates the movement and sensation in these areas due to its extensive distribution throughout the posterior arm and forearm. The radial nerve emerges from the brachial plexus and innervates the triceps muscle as well as the extensor muscles of the forearm, allowing for the extension of the elbow, wrist, and fingers.

Additionally, its sensory branches provide sensation to the skin on the posterior side of the arm, forearm, and part of the hand, making it vital for both motor function and sensory perception in these regions. This anatomical pathway underscores the radial nerve’s crucial role in the overall function and sensory response of the arm and hand.