Jersey finger results from rupture of which tendon due to a sudden force applied to the distal phalanx while the finger is in flexion?

Jersey finger results from rupture of which tendon due to a sudden force applied to the distal phalanx while the finger is in flexion?

• A. Extensor digitorum tendon
• B. Flexor digitorum superficialis tendon
• C. Abductor pollicis longus tendon
• D. Flexor digitorum profundus tendon

Answer: (D)

The main idea is that jersey finger is an injury to the tendon that flexes the fingertip. When a finger is flexed and a sudden force is applied to the distal phalanx, the tendon that pulls the tip of the finger into flexion—the flexor digitorum profundus (FDP)—can rupture or avulse from its insertion. Because the FDP is what flexes the distal interphalangeal joint, its damage leaves the person unable to bend the fingertip at the DIP joint, which is the defining feature of this injury. The other options don’t fit: the extensor tendon controls extension, so its injury causes problems with straightening the finger; the superficial flexor tendon (FDS) mainly flexes the PIP joint, not the DIP; and the abductor pollicis longus is a thumb muscle, not involved in this finger injury.

The main idea is that jersey finger is an injury to the tendon that flexes the fingertip. When a finger is flexed and a sudden force is applied to the distal phalanx, the tendon that pulls the tip of the finger into flexion—the flexor digitorum profundus (FDP)—can rupture or avulse from its insertion. Because the FDP is what flexes the distal interphalangeal joint, its damage leaves the person unable to bend the fingertip at the DIP joint, which is the defining feature of this injury. The other options don’t fit: the extensor tendon controls extension, so its injury causes problems with straightening the finger; the superficial flexor tendon (FDS) mainly flexes the PIP joint, not the DIP; and the abductor pollicis longus is a thumb muscle, not involved in this finger injury.