A Bennet’s fracture is difficult to maintain in reduced position because of the pull of
**Question:** A Bennet's fracture is difficult to maintain in reduced position because of the pull of
A. the ulnar nerve
B. the pronator quadratus muscle
C. the ulnar collateral ligament
D. the ulnar artery and vein
**Core Concept:** Bennet's fracture is a type of distal radioulnar joint fracture. The joint is stabilized by the fibro-osseous band, which consists of the ulnar collateral ligament (UCL), the Guyon canal, and the ulnar nerve.
**Why the Correct Answer is Right:** The correct answer is the pull of the ulnar collateral ligament (UCL). The UCL is essential for maintaining the reduction of a Bennet's fracture. It provides stability to the distal radioulnar joint and prevents the fracture from dislocating.
**Why Each Wrong Option is Incorrect:**
A. Ulnar nerve: Although the ulnar nerve is adjacent to the fracture site, its pull is minimal and does not significantly affect the reduction of a Bennet's fracture.
B. Pronator quadratus muscle: The pronator quadratus muscle is an antagonist to the flexor muscles of the forearm and contributes to supination. Although it is present, its pull is not the primary reason for maintaining a reduced Bennet's fracture.
C. Guyon canal: The Guyon canal contains the ulnar nerve, but its pull does not significantly affect the reduction of a Bennet's fracture. The primary stabilizing factor is the UCL.
D. Ulnar artery and vein: These structures are located within the Guyon canal but do not contribute to the reduction of a Bennet's fracture. The primary stabilizing factor is the UCL.
**Clinical Pearl:** Maintaining a reduced Bennet's fracture is crucial to prevent complications such as malunion, nonunion, and impaired function of the ulnar nerve. The primary focus should be on reducing the fracture and stabilizing it with a cast or splint.
**Correct Answer:** B. The ulnar collateral ligament (UCL) effectively stabilizes the distal radioulnar joint and helps in maintaining the reduced position of a Bennet's fracture. The UCL is crucial for preventing the fracture from dislocating.