Children's Hospital Colorado

Mallet Finger

What is a mallet finger?

A mallet finger is a deformity of the finger that happens when the extensor tendon (the tendon that straightens your finger) is injured or damaged.

  • Sometimes a small piece of bone will also break off during the injury.
  • The tip of the finger will no longer straighten.
  • The fingertip droops.
  • The finger may hurt. It may also be swollen and bruised.
  • Sometimes blood collects under the fingernail, and the fingernail may even come away from the finger.
An illustration of mallet finger, showing where the impact occurs at the tip of the finger causing the bone to fracture. It also shows where the extensor tendon connects to the fractured bone.

What causes a mallet finger?

The tendon is often injured when an object hits the tip of the finger, such as a jamming injury.

Get to know our pediatric experts.

Sarah Sibbel, MD

Sarah Sibbel, MD

Orthopaedic Surgery

Cailin Brazeau, PA-C

Cailin Brazeau, PA-C

Physician Assistant