While the hand is made up of many small bones, the arm consists of three large bones. The arm bones are:
- Humerus: This bone runs from the shoulder to the elbow.
- Radius: This is one of two bones in the forearm. It is on the thumb side of the forearm (radial side). This bone spins around the ulna when you move your palm up and down.
- Ulna: This is the other bone in the forearm. It is on the pinkie side (ulnar side) of the forearm. This bone does not spin.
Learn more about other bones of the upper extremity, including shoulder bones and hand bones in the anatomy section at www.HandCare.org. Here you can also learn about broken bones (i.e. how to know when your arm is broken and how it can be treated) and search for a hand surgeon to treat your injury.