Extracorporeal shock waves are high energy sound waves which can travel through the soft tissue in a body and are used for therapeutic purposes. They are generated by one of several methods (hydraulic, piezoelectric or electromagnetic) and are transfered to the body through a fluid filled cushion. The highest energy waves can be used to destroy kidney and bladder stones within the body, while waves of a lower energy are used to treat chronic pain, often at the insertion or origin of a tendon. They are used in human and veterinary medicine.