The spine is a long chain of bones in vertebrates used to support the back and brain and to protect the spinal cord.
- The spine is an intricate set of bones, muscles, nerves, and discs. It is divided into five regions: cervical (neck bones); thoracic (in the chest); lumbar (low back); sacral (attached to the pelvis); and, coccygeal (the tail bone). Each region has a number of vertebral bones. There are usually seven cervical vertebral bones, twelve thoracic bones, and five lumbar vertebral bones. The sacrum is a single, large, fused bone. The coccyx is made of one or two small bones. The Regions of the Spine