slipped disc, rupture or herniation of an intervertebral disc. These discs separate and cushion the vertebrae, the segments of the spinal column. They are composed of an outer rim of fibrous connective tissue and a gelatinlike inner core. If the fibrous rim breaks the core may leak into the spinal canal, resulting in severe pain that is aggravated by bending, straining, or coughing. Material from the disc may press on spinal nerves and cause numbness or tingling, weakness, or paralysis in the area of the body enervated by those nerves. Slipped discs occur as a result of severe strain or without any apparent stress at all. They are most common in the lower back and neck. Treatment consists of bed rest, usually with a hard board placed beneath the mattress, local application of heat, and the administration of muscle relaxants to relieve spasms. If natural healing fails to occur surgery may be required to remove the disc, and the affected vertebrae fused to keep them from rubbing together.