Illustration copyright 2004 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

The bones (vertebrae) that form the spine (backbone) are cushioned by small, round, flat discs. When these discs are damaged from an injury, normal wear and tear, or disease, they may bulge abnormally or break open. This is called a herniated or slipped disc. If the herniated disc presses on a nerve root, it may cause pain, numbness, or tingling.