The spine (backbone) is composed of 33 interlocking bones called vertebrae that are separated by soft, compressible discs and supported by many different ligaments and muscles. It is divided into five segments: cervical (neck), thoracic (upper and middle back), lumbar (lower back), sacrum (pelvis), and coccyx (tailbone). In each segment, the vertebrae are numbered from top to bottom. For example, a C3 is the third vertebra in the neck area, while a T6 is the sixth vertebra in the thoracic area.
The vertebrae in the spine normally form three curves. These curves allow the spine to absorb shock as you move.
Current as of: March 2, 2020
Author: Healthwise Staff Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine Adam Husney, MD - Family Medicine Kathleen Romito, MD - Family Medicine