Composed of 33 separate vertebrae, the vertebral column, commonly called the spine, forms the rigid backbone of the body and is the major structural support and weight-bearing element in the skeletal system. The vertebral column is the axis of the spine, and in anatomical nomenclature is the axis dividing the body into bilaterally symmetrical halves.

The vertebral column is subdivided into five principal regions, each with their own characteristic vertebrae. Articulations between 24 of the vertebrae allow the spine to remain flexible and this flexibility provides allows a wide range of motion (e.g., flexion and extension) that would not be possible in a fused vertebral column. Nine of the vertebrae are fused and the fusions are important to spinal strength in intensely weight bearing areas.

The most superior region of the spine is the cervical region. Composed of seven cervical vertebrae, this region supports the skull on...