What is a mallet finger?
Tendons are rope like structures that connect muscles to bone. Many of the muscles that move the fingers and thumb are in the forearm. The tendons of these muscles cross the wrist and attach to the bones of the hand. The tendons that straighten the fingers run along the top of the fingers. A forceful blow to the tip of a finger can tear the tendon that straightens the finger, the extensor digitorum communis tendon (the EDC tendon). The force may even be great enough to pull a piece of bone away (avulsion injury) from the end bone of the finger, the distal phalanx. When the EDC tendon is detached, the tip of the finger cannot be straightened and it hangs down abnormally. “Mallet finger” is the term used to describe the condition in which the EDC tendon is torn away from the distal phalanx or a piece of bone is pulled away from the distal phalanx. What does a mallet finger feel like? Initially the end of the finger can feel very painful, and the top of the finger near the fingernail can
Fingers are usually kept in a fine balance by their tendons. The ‘flexor’ tendons run along the palm side of the finger, the ‘extensor’ tendons run along the back of the finger. It is the extensor tendons that are responsible for straightening the finger. The extensor tendon runs up to the area near to where the nail starts. If the tendon breaks or is cut at near this insertion point, then the fingertip will ‘drop’, and the fingertip cannot be straightened. This is termed ‘mallet finger’.
