A surgeon is reconstructing the anterior cruciate ligament of a knee joint from a patient's hamstring tendon. The anterior cruciate is one of the ligaments which connect the femur to the tibia and is often injured during sport. The operator has made a small incision in the knee through which an endoscope has been passed. As well as a viewing channel, the scope has additional channels which allow minute operating instruments to be passed. Keyhole surgery avoids the disruption to tissues and consequent scarring associated with open procedures.Pencil and coloured crayon drawing by Virginia Powell, London 1996.