The American Academy of Orthopedic Surgeons reports that most breaks of the wrist occur due to a fall onto a hand with an outstretched arm, or a reflex attempt to break the fall with the hands. The wrist, or the radius bone, is the most commonly broken bone.
For example, falling while in motion, like off of a bicycle or while skating, often results in a broken wrist, explains the American Academy of Orthopedic Surgeons. In older people weak bones, or osteoporosis, contributes to broken wrists. Someone with weak bones can fall from a motionless standing position with sufficient force and fracture the radius. In younger people, greater force is usually required to break the wrist.