A 20-year-old woman presents with an injured wrist after falling on an outstretched hand. Which carpal bone is most likely fractured?

In cases of wrist injuries involving a fall on an outstretched hand, the scaphoid bone is the most commonly fractured carpal bone. This is primarily due to its anatomical position and its role in transmitting forces from the hand to the wrist. The fall causes the hand to extend, which places significant stress on the scaphoid as it is one of the first bones to impact the ground when the hand is outstretched.

The scaphoid bone is particularly susceptible to fracture because it has a limited blood supply, and fractures can lead to complications such as nonunion or avascular necrosis if not treated properly. The classic presentation after a fracture often includes tenderness in the anatomical snuffbox and difficulty with grip strength.

The other carpal bones listed (lunate, triquetrum, and pisiform) have different mechanisms of injury and are not the most typical fractures associated with the mechanism described. While lunate fractures can also occur, they are less common and often associated with more severe injuries or specific mechanisms like wrist hyperextension or direct trauma. The triquetrum and pisiform bones are usually involved in different types of injuries and are less frequently fractured in the context of a fall onto an outstretched hand. Thus,