The inter vertebral discs are flat, round "cushions" that act as shock absorbers between each vertebra in your spine. There is one disc between each vertebra. Each disc has a strong outer ring of fibers called the annulus, and a soft, jelly-like center called the nucleus pulposus. A disc bulge or herniation may result from high compressive forces or repetitive micro-trauma that results in disc degeneration. This damage causes overstretching and/or tearing of the annular rings (outer portion of the disc), the vertebral endplate and/or ligamentous structures. May result in radicular pain (referred pain to the lower or upper extremities), paresthesia (changes in normal sensation) and inability to perform normal activities.