An injury to the FDP tendon at its point of attachment to the distal phalanx, when there is a forced extension of the DIP joint during active flexion, is called the "jersey finger."(Figure 1). This injury most commonly occurs when an athlete’s finger catches on another player’s clothing while that player is pulling or running away. The tip of the finger at the DIP joint is unnaturally hyperextended while the proximal portion of the finger is flexed. This causes the FDP tendon to partially or completely rupture at its attachment point with or without an avulsion fracture. The ring finger injury accounts for majority of jersey finger cases.
When the FDP tendon is completely ruptured, the affected digit cannot bend at the DIP joint without assistance. In addition to pain, bruising and swelling, jersey finger symptoms may include a popping sensation in the finger at the time of injury, or a lump in the finger or the palm.