A Colles fracture is characterized by which type of displacement?

A Colles fracture is a specific type of fracture that involves the distal radius, typically occurring due to a fall on an outstretched hand. The key characteristic of this fracture is the dorsal displacement of the distal fragment of the radius. In other words, when the fracture occurs, the broken end of the radius is displaced posteriorly (toward the back of the hand). This displacement creates a characteristic "dinner fork" or "bayonet" appearance of the wrist when viewed from the side.

Understanding the mechanism is important; when a person falls and instinctively extends their wrist to catch themselves, the force transmitted through the wrist can lead to this type of injury. The typical population affected by Colles fractures includes older adults, especially those with osteoporosis, as their bones are more susceptible to breaking with such a mechanism.

The other types of displacements mentioned in the alternative choices pertain to different fractures or different bones altogether. For instance, volar displacement generally refers to displacements involving the palm side but is not characteristic of a Colles fracture. Similarly, lateral displacement of the distal femur or medial displacement of the proximal ulna are not relevant to the Colles fracture and indicate injuries in different anatomical locations. Thus, the defining feature of a