Which fracture type occurs typically from a fall backward on an outstretched arm?

A Smith fracture is characterized by a specific mechanism of injury involving a fall backward onto an outstretched arm, which can lead to a fracture of the distal radius with dorsal angulation. This type of fracture often occurs when the wrist is extended during the fall. The force transmitted through the outstretched arm typically results in the fracture of the radius, with the distal fragment being displaced toward the palm of the hand.

Understanding the mechanism behind the other fracture types can clarify why they are less associated with this particular injury. A buckle fracture, also known as a torus fracture, usually occurs in children as the bone bends and compresses, leading to a raised area on one side of the bone rather than a complete fracture. Transverse fractures are straight across the bone and commonly occur from a direct blow or trauma rather than from a fall. Impacted fractures occur when one fragment of bone is driven into another, which generally results from compressive forces rather than the mechanics of falling onto an outstretched arm.

This contextual knowledge reinforces the understanding that the Smith fracture specifically aligns with the scenario of falling backward onto an outstretched arm, making it the correct choice in this situation.