The soft center can rupture through the outer ring and press on a nerve running from the spinal cord to another part of the body. The pain is felt in the area that the nerve supplies. The area most commonly affected is the lumbar intervertebral disks, because they take the most strain. A person can herniate a disk by lifting a heavy object, or by doing some form of vigorous exercise to which the body is not accustomed. Treatment varies according to the severity of the injury.
Herniated disks are more common in young men than women.