**Question:** Bennett's fracture is fracture dislocation of base of metacarpal:

A. Scaphoid fracture
B. PIP joint dislocation
C. Lister's fracture
D. Distal radius fracture

**Correct Answer:** C. Lister's fracture

**Core Concept:** Bennett's fracture is a type of dislocation and fracture involving the base of the fifth metacarpal bone. It is named after Sir Edward Lister, a British surgeon who first described this injury in 1934.

**Why the Correct Answer is Right:** Lister's fracture occurs when the fifth metacarpal is forced laterally and dorsally, resulting in a fracture of the base of the bone and a dislocation of the distal radioulnar joint. This injury is typically caused by a direct blow to the dorsum of the hand or a hyperextension force applied to the wrist joint. The correct answer, Lister's fracture, is the specific type of fracture dislocation involving the base of the fifth metacarpal bone.

**Why Each Wrong Option is Incorrect:**

A. Scaphoid fracture: Bennett's fracture involves the fifth metacarpal, while a scaphoid fracture occurs in the wrist joint. Scaphoid fracture belongs to a different type of fracture, known as a lunate or scaphoid fracture.

B. PIP joint dislocation: Bennett's fracture is a fracture dislocation of the base of the fifth metacarpal, not a dislocation of the PIP (proximal interphalangeal) joint. Bennett's fracture is a specific type of injury involving the radioulnar joint, not the PIP joint.

D. Distal radius fracture: Bennett's fracture is a fracture dislocation of the base of the fifth metacarpal, not a fracture of the distal radius. Distal radius fractures are related to fractures in the forearm, while Bennett's fracture belongs to a different category of injury involving the hand.

**Clinical Pearl:** Bennett's fracture is a common injury in athletes, especially those participating in sports like tennis or golf, where the injury is thought to result from hyperextension forces applied to the wrist joint. Proper diagnosis and treatment of Bennett's fracture involve immobilization, followed by rehabilitation to restore hand and wrist function.