Divisions of the Human Spine As seen from the side view, the spine is divided into three distinct regions, the neck or cervical spine is comprised of seven bones or vertebrae. Anatomists abbreviate the cervical spine with the letter "C". The thoracic spine is comprised of twelve vertebrae and is labeled with the letter "T". The lumbar spine is commonly known as "the lower back", is composed of five vertebrae and is abbreviated with the letter "L".