A Remarkable Structure

The spine is a remarkable structure designed to be flexible and promote mobility, as well as provide strength and stability. It protects the highly sensitive spinal cord and nerve root.

There are four regions of the spine:
  1. cervical (neck) – made up of seven small vertebrae with great range of motion, the cervical spine supports the weight of the head (approximately 10-12 pounds)
  2. thoracic (chest/trunk) – composed of 12 vertebrae, each attached to a rib to create the thoracic cage, which protects many vital organs, including the heart and lungs
  3. lumbar (low back) – usually consists of five large vertebrae, although it is not unusual to have six, and designed to bear most of the body’s weight
  4. sacral (pelvic) – the base of the spine is formed by five vertebrae fused together into a solid unit

At the end of the spinal column is the coccyx or tailbone. Most people have 33 vertebrae in total, although there may be 32 or 34. Variations are usually found in the lumbar or sacral regions.