Your spine is made up of individual bones called vertebra, the spine is split into 3 regions. The cervical region is made up of the 7 vertebra between the base of your skull and the top of the ribs. The thoracic region is made up of the 12 vertebra that interact with the ribs. The lumbar region is made up of the 5 vertebra between the bottom of the ribs and the top of your pelvis. Each vetrabra is roughly circular in shape and between the vertebra is a disc, the disc is made of a tough fibrous outer layer with a soft gel like center. The facet joints are the small joints that connect an individual vertebra with the vertebra above and below it. These facet joints contain small ligaments which connect to the facet joints on adjacent vertebra providing additional stability, there is a long strong ligament which runs nearly the entire length of the spine alongside the various muscles which allow the spine to move in various ways. The spinal cord sits protected inside the spine, nerves from the spinal cord come out at each level inbetween the vertebra to supply various parts of the body with signals.