False-colour X-ray of the human pelvis showing an artificial (prosthetic) hip joint. The metal implant which forms the ball of the ball & socket joint is coloured blue. Before locating the new joint, the bone of the head of the femur is removed and the upper part of the long bone drilled to receive the metal shaft of the new, metal femoral head, which is then cemented into place. Blue implant, gold & red bone. Black background.