A herniated disc is a condition that affects the back. It can cause pain, numbness, or tingling down one or both legs.
The discs that sit between the vertebrae have a tough outer shell and jelly-like center. The outer shell of the discs can sometimes break open, spilling the jelly material inside. This is what doctors call a herniated disc.
Herniated discs can cause symptoms, because the jelly material that spills out of them can irritate nearby nerves. Plus, the disc itself can bulge and press on nerves.