X rays are images which are essentially shadows produced when high intensity electromagnetic waves (x rays) are "shot" through the body.  Although this technology is old, it is excellent for picking up fractures of bones, mis alignment of the spine, and destruction of bone from tumors or other lesions.  It shows bone much better than soft tissue.  Pregnant women should alert the x ray technologist and their physician before undergoing this procedure, as it may be potentially harmful to the fetus.