The human vertebral column is the backboneorspine, consisting of twenty-four articulating vertebrae, and nine fused vertebrae in the sacrumand the coccyx. The vertebrae in the column are separated from each other by intervertebral discs. It houses and protects the spinal cordin its spinal canal. There are normally thirty-three vertebrae; the upper twenty-four are articulating and separated from each other by intervertebral discs, and the lower nine are fused, five in the sacrumand four in the coccyxortailbone. The articulating vertebrae are named according to their region of the spine. There are seven cervical vertebrae, twelve thoracic vertebraeand five lumbar vertebrae. The number of vertebrae in a region can vary but overall the number remains the same. The number of those in the cervical region however is only rarely changed. Structural support for the body, allowing us to stand upright. The spine supports about half the weight of the body.