What typically causes a herniated disc?

A herniated disc occurs mainly due to a bulging or leaking of the nucleus pulposus, which is the soft inner material of an intervertebral disc. The intervertebral discs function as cushions between the vertebrae, helping to absorb shock and allow for movement of the spine. When the outer layer of the disc, known as the annulus fibrosus, weakens or tears, the nucleus pulposus can protrude through the opening, leading to a herniation. This can compress nearby nerves, resulting in pain, numbness, or weakness in the limbs.

Factors contributing to this condition include age-related degeneration, which can decrease the hydration and elasticity of the disc, making it more prone to injury. Trauma or strain from activities that involve heavy lifting, twisting motions, or improper body mechanics can also contribute to the risk of disc herniation, but the fundamental mechanism is the failure of the disc’s structure allowing the nucleus material to escape. Other potential causes listed, such as infection or osteoporosis, are less common and do not primarily account for the direct mechanics of a herniated disc.