Final answer:
The radial artery supplies the thumb side of the arm and back of the hand.
Step-by-step explanation:
The artery that supplies the thumb side of the arm and back of the hand is the radial artery. The radial artery is formed from the anastomosis of the radial and ulnar arteries and supplies blood to the hand and digital arteries. It parallels the radius and gives off smaller branches until it reaches the carpal region where it fuses with the ulnar artery to form the superficial and deep palmar arches.