A herniated disc is a condition in which part of an intervertebral disc bulges through its protective covering and may press on a nerve. Pressure on the nerve can cause pain that begins in the back or neck and often extends down a leg (causing sciatica) or an arm.

A herniated disc sometimes follows a single, traumatic injury. However, in most cases it is due to gradual, aging–related deterioration, such as degenerative disc disease or spinal arthritis.

Most herniated discs begin to heal after a short period of rest and home-based remedies such as anti-inflammatory drugs, cold therapy and heat therapy. In some cases pain may linger and require professional treatment, such as physical therapy or nonsurgical spinal decompression. In rare cases, spinal surgery is recommended. Herniated discs that result in sudden muscle weakness or loss of bowel or bladder control are potentially serious conditions that may require immediate emergency surgery.

Disc degeneration or herniation in itself may not be painful at all. Research has shown that young healthy adults in their 30s without any complaint of back pain may have evidence of herniated discs on MRI (magnetic resonance imaging).