Vertebral column or rachis (profile view): bony axis of vertebrates, comprised of the set of vertabrae from the base of the skull to the pelvis.
5 fused vertebrae: the vertebrae that form the end of the spine, the coccyx.
Coccyx region: bone comprised of the fused, atrophied vertebrae at the end of the sacrum.
Sacral region: bone that is jointed with the hip bone to form the pelvis.
Lumbar region: the part of the spine in the area of the loins (5 vertabrae).
Thoracic region: the part of the spine in the area of the thoracic cage (12 vertebrae).
Cervical region: the part of the spine in the area of the neck (7 vertebrae).