Final answer:
The clavicle is the most commonly fractured bone in a fall due to its position and the way force is transmitted to it when falling with outstretched arms or receiving a strong blow to the shoulder.
Step-by-step explanation:
The bone that is most commonly fractured in a fall is the clavicle. When a person falls onto their outstretched arms or when the lateral shoulder is subjected to a significant impact, the force exerted is usually transmitted to the clavicle, causing it to break. This break typically occurs between the middle and lateral portions of the bone due to the clavicle's position and vulnerability. The sternoclavicular joint is strong, providing stability at one end of the clavicle, but this ultimately means that the clavicle itself is more likely to fracture under stress. Following a fracture, the muscles around the shoulder can pull the fragments of the clavicle in different directions, potentially causing them to overlap or displace.