ABOUT X-RAYS: Like visible light, X-rays are wavelike forms of electromagnetic energy carried by tiny particles called photons. The only difference is the higher energy level of the individual photons, and their corresponding shorter wavelengths, which make them undetectable by the human eye. X-ray photons have energies that range from hundreds to thousands of times higher than those of visible photons. X-ray machines image the outline of bones and organs, while a CT scan machine forms a full three-dimensional computer model of the inside of a patient's body. Doctors can even examine the body one narrow slice at a time. The X-ray beam moves all around the patient, scanning from hundreds of different angles, and the computer takes all that information to compile a 3D image of the body.
THE SPINE: The back is made up of bones, muscles and other tissues that compose the body's trunk, from the neck to the pelvis. The spinal column is the centerpiece. It supports the upper body's weight and houses the spinal cord, which carries the signals that control movement and convey sensations. The spinal column is made up of more than 30 bones, called vertebrae, stacked on top of one another. Each contains a round hole that creates a channel. Small nerves, called roots, enter and emerge from the spinal cord through spaces between the vertebrae. The spaces are protected by round, spongy pads of cartilage called intervertebral discs; these enable some flexibility in the lower back and serve as shock absorbers to cushion the bones as the body moves. The entire network is held in place by bands of tissue called ligaments and tendons. Damage to these disks and the spinal cord can occur because of impacts like car accidents, disease, or over time as a result of general wear and tear.