The spine is the major support system of the entire body, and consists of bones, cartilage, ligaments, muscles, the spinal cord and nerves. Although the spinal column is very strong and supportive, it is stabilized by muscles and ligaments, and can be very flexible because of the soft, cartilage cushions (intervertebral discs) between the individual spine bones (vertebrae) that allow a lot of movement and bending.
The spine functions to:
- Provide support and balance for the entire body
- Allow flexibility and bending
- Protect the spinal cord and nerves
- Store calcium and other important nutrients
- Produce blood cells
The spine is composed of 33 bones (vertebrae) that are stacked on top of each other. The lowest 9 bones of the spine are fused (grown together), and are called the sacrum and coccyx. There is a cartilage cushion (intervertebal disc) in-between each of the 24 mobile spine bones. The vertebrae have a large hole in the back part of the bone called the spinal canal. The spinal cord and nerves are protected within the spinal canal and extend the entire length of spine from the brain down to the tailbone. The nerves within the spinal cord and spinal canal carry the signals from the brain to the muscles and the rest of the body. The spine is essentially straight when looking at someone directly (head-on view) but is slightly curved in three areas when looking at someone from the side view. The upper region, called the cervical spine, has a lordotic (curved backward) curve. The middle region, call the thoracic spine, has a kyphotic (curved forward) curve. The lower region, called the lumbar spine, has a lordotic (curved backward) curve. Normal spinal alignment is essential for the body to be properly balanced.
In addition to support, flexibility, and protection, the spine bones (vertebrae) store the majority of the body .s calcium, as well as other important nutrients. The marrow within the spine bones is also a major producer of blood cells for the body, cells which are important for circulating oxygen and fighting infection.