Broken wrist. Coloured X-ray of a Colles' fracture of the wrist (yellow), an injury usually caused by the extension of a hand to lessen the impact of a fall. A Colles' fracture may also be associated with a break of the styloid process of the ulna (down left), as in this case. The styloid process allows the attachment of wrist ligaments. This type of fracture is common in the elderly, whose bones have been weakened by osteoporosis. Treatment involves the surgical repositioning of the bones followed by immobilisation in a cast. The injury slightly increases the risk of developing arthritis in the joint.