In medicine, mallet finger, also baseball finger, dropped finger and (more generally) extensor tendon injury, is an injury of the extensor digitorum tendon of the fingers at the distal interphalangeal (DIP) joint. It results from hyperextension of the extensor digitorum tendon, and usually occurs when a ball (such as a baseball, basketball, or volleyball), while being caught, hits an outstretched finger and jams it.