A patient arrives with a tender fingertip injury with a noticeable deformity. There is a history of a sudden resisted flexion of the distal interphalangeal (DIP) joint, such as when the fingertip is struck by a ball or jammed against a stationary object, resulting in pain and tenderness over the dorsum of the base of the distal phalanx. This injury can occur with relatively minor trauma (such as jamming a finger while reaching for a light switch in the dark) or even as a result of a direct blow to the dorsum of the finger. It may or may not be accompanied by swelling and ecchymosis over the DIP joint. When the finger is at rest or held in extension, the injured DIP joint remains in slight or moderate flexion (Fig. 106.1).