What are Extensor Tendon Injuries?

The extensor tendons run along the back of the hand and wrist and extend the fingers. These are tendons you see on the back of your hand when you flex your fingers. The muscles for the extensor tendons attach in the forearm and go through tight compartments and pulleys on the back of the wrist before inserting on the finger.  The index and small finger have two tendons, the long and ring fingers only have one extensor tendon, and the thumb has two extensors, but they attach at different joints.

Symptoms & Causes

Traumatic injuries or lacerations can easily injure extensor tendons because they are so close to the skin. They can also rupture as a result of excessive swelling from a fracture or rheumatological condition.


Extensor tendon injuries are usually easier to treat than flexor tendon injuries, and they have better postoperative results. Acute lacerations are treated with a primary repair, and ruptures are typically treated by transferring one of the extra tendons to the injured one. The long thumb extensor tendon is the most common site of rupture. In this case, we take the extra index finger tendon and transfer it to the thumb. In addition to occupational therapy, it is crucial to have a therapist make a custom splint for the patient that accounts for their individual level of injury to increase the chance of optimal outcomes. We often send the patient to the therapist before surgery to get acquainted with the process and to make a splint.

Extensor Tendon Injuries

Extensor Tendon Injuries

Additional Resources