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Hand and Wrist

Extensor Tendon Injury

Extensor tendons are located on the back of the hands and fingers thus making them susceptible to even the slightest injuries. Extensor tendons are attached to muscles in the forearm and become flat and thin as they continue to the fingers. In the fingers, the extensor tendons are joined by smaller tendons from the muscles in the hand, which allow delicate finger motions and coordination.

There are six extensor tendons compartmentalized within the wrist. The extensor tendons are held in place by the extensor retinaculum. As the tendons travel over the wrist they are enclosed within synovial tendon sheaths for added protection. These sheaths reduce friction in the tendons as they travel through the compartments that are formed by the attachments of the extensor retinaculum to the far end of the radius and ulna (bones of the forearm).

Extensor tendons are just beneath the skin and directly on the bone. These tendons are located on the back of the hands and fingers and due to their location, they can be easily injured even by a minor cut. Jamming a finger can cause these tendons to rip apart from the bone and become loose.

Due to the fact that extensor tendons have little protection on the posterior of the hand it is easy for them to be injured. Jammed fingers, cuts, broken or fractured fingers, and direct blows can all cause an extensor tendon injury. Common extensor tendon injuries include:

  • Mallet Finger – This injury refers to the droop of the end joint where an extensor tendon has been directly separated from the bone. The result of such an injury is a finger that cannot be straightened.
  • Boutonnière deformity – Such an injury describes the bent-down/flexed position of the middle joint of the finger from a tear of the extensor tendon.
  • Lacerations – Cuts on the back of the hand that injure the extensor tendons cause problems in attempting to straighten the finger at the large joint where the fingers join the hand.

There are many common injuries associated with an extensor tendon injury, and thus there are many symptoms associated with those injuries. Common symptoms of an extensor tendon injury include:

  • Pain at the dorsal DIP joint
  • Inability to extend relevant joints in the finger
  • Flexion deformities
  • Sharp Pain
  • Swelling
  • Bruising
  • Tendon deformities
  • Inability to bend the finger

Upon visiting a physician, the physician will explore the hand and examine and test it for any pain, swelling, bruising, and deformities. The physician will also ask the patient to attempt to extend and bend the injured finger. If a diagnosis cannot be rendered then and there, the physician will recommend a resisted dorsiflexion test. This test requires the patient to lift the affected finger(s) while the physician applies pressure to the top of the finger(s). If the patient feels pain on the top of the hand, then it is possible that the extensor tendon has been injured.

Lacerations that split or tear the tendon normally require stitches. Tears caused by jamming the fingers and producing deformities within the joints and tendons typically require that the individual wear a splint. Splints stop the healing ends of the tendons from pulling apart from the bones and should be worn at all times until the tendon is completely healed. The attending physician will apply the splint at the affected area and will inform the patient of how long the splint should be worn. On occasion, a pin is inserted through the bone across the affected joint as an internal splint.

Seeking Treatment

The Center for Orthopaedic Specialists has been providing California residents with expert treatment for years. If you are currently experiencing any of the aforementioned symptoms, or suspect that you have injured your extensor tendon, contact the Center for Orthopaedic Specialists today!

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