This is a lateral (side) view of a normal spine. The human spine is made up of 33 vertebral bones. The drawing shows the locations of the five major spinal levels. The cervical region has seven vertebrae (C1 through C7), the thoracic region has twelve vertebrae (T1 through T12) and the lumbar region has five vertebrae (L1 through L5). The sacral region consists of five vertebrae, all fused together to form one continuous bone mass known as the sacrum (S1). The coccygeal region consists of four vertebrae, all fused together to form the coccyx or tailbone.
Detailed views of a vertebra and vertebral segment. The drawing to the right represents a top view of a lumbar vertebra. The drawing below is a lateral (side) view of a segment of three lumbar vertebrae.