Sprains and fractures are the most common types of wrist injury. A sprain occurs when a ligament (a tough band of tissue that connects bones to other bones) becomes overstretched or torn. Wrist fractures occur when a person falls onto his or her outstretched hand, with the weight landing on the palm. A small bone in the wrist called scaphoid is the most likely to break. The radius bone, which is in the end of the forearm, may also break in this type of fall.