Ever since I accidentally smashed the end of my finger with a hammer, I haven't been able to straighten the tip of my finger. My doctor called my problem mallet finger. Why can't I straighten my finger now?

A mallet finger results when the extensor tendon is torn from the attachment on the bone. This most often occurs from trauma, such as closing the finger in a door. When the extensor tendon is torn, a small fragment of bone may be pulled, or avulsed, from the distal phalanx. The result is the same in both cases--the end of the finger droops down and cannot be straightened.