Herniated discs of the spine

The spine is divided into three main segments: the cervical spine, thoracic spine, and lumbar spine. There are seven cervical, twelve thoracic, and five lumbar vertebrate, and an intervertebral disc lies between each adjacent vertebrae. The sacrum and coccyx (pelvic area) do not contain discs. The vertebrae sit on top of one another like a stack of blocks with the intervertebral discs lying in between to function as a cushion and allow movement at each level. The spinal cord runs through the spinal canal, ending at L1. Spinal nerves exit the cord between each vertebrae. The spinal nerves in the lumbar spine come down from the spinal cord like a horses tail (cauda equina). Herniated discs can contact either the spinal cord or nerves and irritate them, producing symptoms of pain, numbness, or weakness.