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Anatomy

In order to better understand any abnormalities in your spine, you should begin by understanding some basic spinal anatomy.

The human spine is divided into three portions: the cervical spine (neck area), the thoracic spine (upper back) and the lumbar spine (lower back).

The spine itself is made up of bones, joints, discs, nerve structures, spinal cord, muscles and ligaments that all work together to allow for movement and support for the body.

The Spinal Bones

The spinal column is made up of twenty-four individual bones called vertebrae. Each vertebra in the spinal column consists of the vertebral body in the front, the facet joints in the back and the pedicles, which join the vertebral bodies to the facet joints. Vertebrae provide support for the spine and are connected by intervertebral discs. Intervertebral discs are composed of strong tissue masses that are filled with gel, and they allow the torso to bend, twist and absorb shock. There are seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae.

The vertebrae in the cervical spine begin at the base of the head. In this area there are eight pairs of cervical nerves, which control movement in the neck, arms and upper body. The cervical vertebrae are strong and tough in order to support the weight of the head.

The thoracic spine contains twelve vertebrae and twelve pairs of ribs. The nerve roots in this area are responsible for movement in the midsection of the body. The ribs provide the structure for the chest wall and protect many important internal organs.

The largest and strongest bones in the spinal column are the lumbar vertebrae. The lumbar portion of the spine supports the bulk of the body's weight. The five pairs of nerve roots located in the lumbar spine are responsible for movement and sensory functions in the lower extremities of the body.

At the lower portion of the spinal column are two other spinal bones: the sacrum and the coccyx, or tailbone. The sacrum consists of five bones naturally fused together, and the coccyx consists of four small attached bones. These bones look different than any other bones in the spine. The sacrum is triangular in shape and the coccyx is attached to the lower end of this triangle. The nerve roots in this area control the pelvic organs and buttock muscles.

  • Published: December 13, 2001
  • Updated: July 22, 2008