Vertebral Column with Section and Vertebrae Labels
Lateral or Side View (left) and Posterior or Back View (right)
The spine consists of 33 vertebrae, the sacrum, and the coccyx. Separating each vertebrae are the intervertebral discs. The spinal column is normally divided into 3 major sections: cervical, thoracic and lumbar. The sacrum and coccyx are sometimes called the pelvic section.
The cervical section consists of 7 vertebrae labeled C1 through C7. They are the smallest and lightest vertebrae, with short spinous processes. C1 is also known as the atlas and C2 as the axis. The atlas is a ring of bone sitting on a bone projection of the axis. This is what allows the head and atlas so much rotational movement.
The thoracic section consists of 12 vertebrae labeled T1 through T12. The rib cage are joined to the thoracic vertebrae. This attachment to the ribs provides for only limited range of movement of the thoracic section of vertebrae.
The lumber section consists of 5 vertebrae labeled L1 through L5. These are the largest of the vertebrae and bear much of the upper body weight.
The sacrum is a single bone structure made from 5 fused vertebrae with no intervertebral discs. The sacrum is connected to the hip bones. The coccyx is also a single bone structure, made of 3 fused vertebrae with no intervertebral discs.
The vertebrae are the weight bearing structures of the spinal column. They support the upper body weight and transfer this weight to the sacrum, which in turn transfers the weight to the hip bones and legs. Curves in the spine provide support and elasticity for distributing the body weight during movement.