Anatomy of the Spine

The spine is a column of bones which serve to protect the spinal cord and the nerves that control movement in our extremities. The spinal column is one of the most vital parts of the human body, supporting our trunks and making all of our movements possible. When the spine is injured and its function is impaired the consequences can be painful and even disabling. According to estimates, 80 percent of Americans will experience low back pain at least once in their lifetime. A small number of patients will develop chronic or degenerative spinal disorders that can be disabling.

Men and women are equally affected by lower back pain, and most back pain occurs between the ages of 25 and 60. However, no age is completely immune. Approximately 12% to 26% of children and adolescents suffer from low back pain. Fortunately most low back pain is short-lived, and will resolve itself in three days to six weeks with or without treatment. If pain and symptoms persist for longer than 3 months to a year, the condition is considered chronic.

Humans are born with 33 separate vertebrae (spinal bones). By adulthood, most have only 24 vertebrae, as the lower sacral bones fuse during normal development. The spine is divided into 4 divisions or levels. From top to bottom the levels include: cervical, thoracic, lumbar and sacral. The cervical (neck) spine consists of 7 vertebrae numbered from C1 through C7. The thoracic (middle spine) spine consists of 12 vertebrae paired with ribs through this section. The thoracic vertebrae are numbered from T1 through T12. Problems in the thoracic spine typically do not result in any problems in the arms or legs. The lumbar spine consists of 5 vertebrae numbered from L1 through -L5. Below the lumbar spine, nine vertebrae at the base of the spine grow together and make up the sacrum and coccyx bones. Five form the triangular bone called the sacrum. The area in the lower back where two dimples are seen in most everyone's back (historically known as the "dimples of Venus") are where the sacrum joins the hipbones, called the sacroiliac joint. The lowest four vertebrae form the tailbone or coccyx bone.

The anatomy of the spinal column is extremely well designed to serve many functions. All of the elements of the spinal column, through the complex interaction of vertebrae (bones), ligaments and muscle, serve the purpose of protecting the spinal cord, and the nerves that surround it. The spinal cord and the spinal nerves provide communication to the brain, and allow mobility and sensation to the entire body The back is also the powerhouse for the entire body, supporting our trunks and making all of the movements of our head, arms, and legs possible.