Spinal disc herniation (aka slipped disc) is a condition affecting the spine, where there is a tear in anulus fibrosus (i.e. the outer, fibrous ring) of an intervertebral disc, allowing the nucleus pulposus (soft, central portion) to bulge out beyond the damaged outer rings.

• Age-related degeneration of the anulus fibrosus, usually
• Trauma
• Lifting injuries
• Straining

• Tears are almost always postero-lateral in nature, owing to the presence of the posterior longitudinal ligament in the spinal canal
• This tear in the disc ring may result in the release of inflammatory chemical mediators, which may directly cause severe pain, even in the absence of nerve root compression
• Disc herniations are normally a further development of a previously existing disc "protrusion", where the outermost layers of the anulus fibrosus are still intact, but can bulge when the disc is under pressure [but unlike a full hernation, none of the nucleus pulposus escapes beyond the outer layers]. Most minor herniations heal within several weeks

• Anti-inflammatory Tx, for pain associated w/ disc herniation, protrusion, bulge or disc tear, is generally effective
• Surgical intervention, is required in severe herniation, as it may not heal on its own accord

• Although the condition is widely referred to as a "slipiped" disc, it is not medically accurate, as the spinal discs are firmly attached between the vertebrae and can't "slip"