The intervertebral discs serve as joints between the vertebral bodies, providing both structural support and flexibility to the spinal column. Intervertebral discs do not remain structurally intact over a lifetime and degenerate as a natural part of aging. Degenerated discs do not react to stresses and forces the same as healthy discs. When too much stress is applied to a degenerated disc, tears can result. Evidence suggests that when a tear is present, sensory nerve endings can grow into the tear and transmit pain.