Colles' wrist fracture. Frontal X-rays of the hand and wrist bones of a patient with a type of wrist fracture known as a Colles' fracture. The left image shows the fracture, which is at centre left. The ends of the arm bones (ulna and radius) have been broken at the wrist, having been displaced up and over the bones of the hand. This type of fracture is usually caused by using the hand to break a fall. It is common in the elderly, whose bones have been weakened by osteoporosis. The right image shows the fracture after being treated by surgical repositioning of the bones and the insertion of pins to hold them in place, followed by immobilisation in a plaster cast.