Mallet finger is:
**Core Concept**
Mallet finger is a type of injury to the extensor tendon of the finger, specifically at the distal interphalangeal (DIP) joint. This tendon injury occurs when the fingertip is struck by an object, causing the tendon to rupture or become partially torn. The resulting deformity is characterized by the inability to extend the DIP joint.
**Why the Correct Answer is Right**
The mechanism of mallet finger involves a sudden, forceful blow to the fingertip, which causes the extensor tendon to snap or rupture. This typically happens when a person attempts to catch a ball or is struck by an object. The injury leads to an inability to extend the DIP joint, resulting in a flexion deformity. The extensor tendon, which is responsible for extending the DIP joint, is compromised, making it difficult to straighten the finger.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the definition of mallet finger.
**Option B:** This option does not describe the typical mechanism or location of mallet finger.
**Option C:** This option is incorrect because mallet finger specifically involves the extensor tendon of the finger, not the flexor tendon.
**Clinical Pearl / High-Yield Fact**
Mallet finger is typically treated with immobilization in extension using a splint or cast for several weeks to allow the tendon to heal. Untreated mallet finger can lead to chronic flexion deformity and decreased finger function.
**Correct Answer: C. Mallet finger is an injury to the extensor tendon of the finger, specifically at the distal interphalangeal (DIP) joint.**