Tendons are responsible for connecting muscles to bone. The extensor tendons are located on the back of the hand and fingers. They let you open your hand and straighten your fingers. An extensor tendon injury is a cut or tear to one of these tendons. When they are damaged, you can lose the ability to extend your hand and/or finger(s). Two common extensor injuries are:

  • Mallet finger—the tendon is affected at the last joint on the finger, usually from a jammed finger
  • Boutonniere Deformity—the tendon is affected at the middle joint, usually caused by an arthritis-like condition

Extensor Tendons of the Hand
extensor tendon
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Extensor tendon injuries may be caused by:

  • A cut or laceration to back of hand or fingers
  • Broken bones
  • A crush injury
  • An open wound or cut
  • Jamming a finger
  • Arthritis
  • Nerve compression