The bones that form your spine are cushioned by small discs that act as shock absorbers and keep the spine flexible. When a disc is damaged, it may bulge or break open. This is called a herniated disc, slipped disc, or ruptured disc. It may push on the nerves and cause pain, numbness, or weakness in the area where that nerve travels. Most herniated discs happen in the lower back. Many people have herniated discs but don't have any symptoms.