Forearm

The two bones of the forearm are the radius laterally and the ulna medially. They articulate proximally with the humerus at the elbow joint and contribute to the wrist joint distally. They are connected by a strong interosseus membrane between their shafts, and synovial pivot joints at each end. Both are long bones, the ulna being expanded proximally and the radius distally. The shaft of the radius is convex laterally, allowing it to move around the ulna carrying the hand with it into pronation.