AEMCA Practice Exam

What defines a Colles fracture?

1. Fracture of the 5th metacarpal

2. Fracture of the distal radius with posterior displacement of the wrist and hand

3. Fracture of the distal radius with anterior displacement

4. Fracture of the femur

The correct answer is: Fracture of the distal radius with posterior displacement of the wrist and hand

A Colles fracture is specifically characterized by a fracture of the distal radius in the forearm, which typically occurs as a result of a fall onto an outstretched hand. The key aspect of this type of fracture is that it results in posterior displacement of the wrist and hand. This means that when the fracture occurs, the distal fragment of the radius shifts backward, leading to a classic "dinner fork" deformity. In contrast, fractures of the 5th metacarpal, which involve a different part of the hand, do not describe a Colles fracture. Additionally, a fracture with anterior displacement of the distal radius would not meet the criteria for a Colles fracture, which is specifically associated with posterior displacement. Lastly, fractures of the femur involve a completely different bone and location, making them unrelated to the definition of a Colles fracture. Thus, the correct identification of a Colles fracture centers on the specifics of the distal radius and the nature of the displacement involved.