The radius is the side of the radius bone in the forearm, the side of the hand where the thumb is located. There are two bones in the human forearm, the ulna, which is located on the inside, and the radius, which is located on the outside, when the hand is positioned palm forward. When describing the exact location of an injury, it is often described in terms of the ulnar and radial sides, with ulnar referring to the side of the ulna that is located on the medial side and radial referring to the side of the radius that is located on the lateral side. For example, describing which side of the forearm a forearm trauma is located on would be described as being on the radial or ulnar side of the forearm. In the event of a forearm trauma or other disease, it is important to go to a regular hospital and seek timely medical attention.