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Herniated disk

  • Definition

    A herniated (slipped) disk occurs when all or part of a spinal disk is forced through a weakened part of the disk. This places pressure on nearby nerves.

    See also:

    • Acute low back pain
    • Chronic low back pain
    • Sciatica

    Alternative Names

    Lumbar radiculopathy; Cervical radiculopathy; Herniated intervertebral disk; Prolapsed intervertebral disk; Slipped disk; Ruptured disk; Herniated nucleus pulposus


    Causes, incidence, and risk factors

    The bones (vertebrae) of the spinal column run down the back, connecting the skull to the pelvis. These bones protect nerves that come out of the brain and travel down your back, forming the spinal cord. Nerve roots are large nerves that branch out from the spinal cord and leave your spinal column between each vertebrae.

    • The spinal vertebrae are separated by disks filled with a soft, gelatinous substance. These disks cushion the spinal column and space between your vertebrae.
    • These disks may herniate (move out of place) or rupture from trauma or strain. When this happens, the spinal nerves may become compressed, resulting in pain, numbness, or weakness.
    • The lower back (lumbar area) of the spine is the most common area for a slipped disk. The cervical (neck) disks are affected 8% of the time. The upper-to-mid-back (thoracic) disks are rarely involved.

    Radiculopathy refers to any disease that affects the spinal nerve roots. A herniated disk is one cause of radiculopathy (sciatica).

    Disk herniation occurs more frequently in middle-aged and older men, especially those involved in strenuous physical activity. Other risk factors include any conditions present at birth (congenital) that affect the size of the lumbar spinal canal.