Back and Neck Pain
Anatomy of the Spine
The spine has three main parts:
- The spinal column-bones and discs
- Neural elements-the spinal cord and nerve roots
- Supporting structures-muscles and ligaments
The spinal column consists of individual bones called vertebrae. The vertebrae provide support and protection to the spinal cord. The spine contains seven cervical vertebrae (C1-7) in the neck; twelve thoracic vertebrae (T1-T12) in the mid-back; five lumbar vertebrae (L1-L5) in the lower back; five fused bones in the sacrum; and three to five fused bones forming the coccyx or tailbone.
On the front side of the spine, the vertebrae are connected by intervertebral discs. The discs contain a harder outer ring called the annulus fibrosis and an inner jelly filled center called the nucleus pulposus. The annulus connects the vertebrae while the nucleus provides shock absorption properties of the spine and allows the spine to flex and bend. On the back side of the spine, a pair of joints called the facet joints allows the spine to twist and bend forward.
Nerves connecting the brain to the body make up the spinal cord. The spinal cord runs through the center of each protective vertebra. Nerves branch off from the spinal cord to organs and muscles including the arms and legs. The nerves carry messages from the brain to the organs, muscles, and limbs.
The soft tissue supporting structures of the spine, the muscles and ligaments, enable the spine to function in an upright position, and allow the trunk to move in a variety of positions. They are vital to maintaining stability to the spine.