The spine is made of bones called vertebrae with jelly-like discs between. It is divided into three sections from top to bottom: cervical, thoracic, and lumbar. You have 24 vertebrae: 7 cervical, 12 thoracic, and 5 lumbar. Vertebrae are named by their section and position from top to bottom (e.g. C5). Discs are named by the vertebrae they fall between (e.g. L4-L5). You have 4 “special” vertebrae: the Atlas and Axis at the top of the spine, and the Sacrum and Coccyx (tail bone) at the bottom. The Sacrum begins as 5 independent vertebrae that fuse in your late teens.