A herniated disc (also sometimes called a ruptured disc) is caused when cartilage and fluid between vertebrae in the spine presses on the nerves around the backbone. This often causes the disc to visibly bulge.

With aging, these discs are less able to cushion the bones of the spine.  This natural aging process causes the disc to tear and press on the nerves around it. When part of a disk presses on a nerve, it can cause pain in both the back and the legs. The location of the pain depends on which nerves in the spinal column are affected by the bulging disc.  Some people experience the pain of a herniated discs as a fiery sensation that spreads over the buttocks and goes down the back of one thigh and into the calf. Other people experience pain in both legs and numb and tingling sensations.

Herniated disks are most common in people in their thirties and forties.