Anteroposterior radiograph of a forearm with an anteriorly dislocated radial head showing mid-axial lines in the proximal, middle, and distal radius and ulna used for measurement of the parameters. The line AA’ indicates the rotational axis of the forearm connecting from the center of the radial head to the center of the distal ulna. Proximal radial tilt angle, the angle between lines AA’ and a; proximal ulnar tilt angle, the angle between lines AA’ and e; proximal radioulnar angle, the angle between lines a and e; middle radial tilt angle, the angle between lines AA’ and c; middle ulnar tilt angle, the angle between lines AA’ and f; distal radial tilt angle, the angle between lines AA’ and d; and distal ulnar tilt angle, the angle between lines AA’ and g. a: the axis of the radial neck, b: the axis of the proximal radius, c: the axis of the middle radius, d: the axis of the distal radius, e: the axis of the proximal ulna, f: the axis of the middle ulna, g: the axis of the distal ulna.