X-ray of an elbow is a painless test that is used to take a picture of a person's elbow. During the examination, an X-ray machine sends a beam of radiation through the elbow, and an image is recorded on special X-ray film or a computer. This image shows soft tissues and bones of the elbow, humerus, and the radius and ulna. The X-ray image is black and white. The lateral elbow view is part of the examining the distal humerus, proximal radius and ulna. The used to assess both the anterior humeral and the radiocapitellar line.