A vertebra is any of the 33 bones which forms the spinal column (vertebral column). Each vertebra has a body and posterior to the body is the vertebral arch which protects the spinal cord. The 33 vertebrae are: 7 cervical (neck) vertebrae 12 thoracic (upper back) vertebrae 5 lumbar (lower back) vertebrae sacrum (5 fused vertebrae) coccyx (4 fused vertebrae)