The \spine, of a vertebrate, is the vertebral column. The column is a bony structure, which attempts to protect the spinal cord and support the appendicular skeleton.
The spine is divided, in most land mammals, into five sections: the cervical (neck) section, the thoracic section, the lumbar section, the sacrum, and the tail or coccyx.
The topmost vertebrae of the spine are the Axis and the atlas. These are specially adapted to allow a full range of movement for the skull.
The spine serves two major purposes - firstly, it gives the skeleton its strength by supporting the back, and secondly, it protects the vital spinal cord from damage.