A Doctor Explains What You Need to Know About the Regions of the Spine

By Dr. Molly Casey

The spine houses and protects the most important system in your body, the nervous system. Your brain sends information via electrical impulses through the spinal cord and out miles of nerves to every cell, organ, system, and structure in the body. Those cells, organs, systems, and structures send information back through those nerves to the spinal cord and up to the brain. This is your communication system. This is the only system in the body encased entirely in bone by itself because it is that important.

Spinal Function

There are three functions of the spine itself. The first is protection of the brain stem, spinal cord, and nerve roots. The second is to act as the mainframe of the body, offering structural support and balance that allows humans to maintain an upright posture. The third function is to provide flexible motion of the body.

The Regions

There are four different regions to the spine. From the skull down to the tailbone, they are called cervical spine, thoracic spine, lumbar spine, and sacral spine.

Cervical spine - The cervical spine is composed of seven bones that are abbreviated as C1, C2, and so on through C7. The cervical spine is the neck area and connects the skull to the mid back region. The first two cervical bones are distinct in structure and have names, atlas (C1) and axis (C2), but no other vertebrae in the spine have specific names. C1 is round/oval in shape with the center fully open as the brainstem sits in it. C2 has a large piece of bone (called the odontoid process) that extends up into the back of the atlas and serves as an axis of rotation for C1. The cervical spine offers a wide range of motion; most rotation of the head occurs at C1/C2. The cervical spine protects the brain stem and offers support to the skull.

Thoracic spine - There are 12 vertebrae in the thoracic spine. This is what lay people think of as the mid back. It connects the cervical and lumbar spine. The abbreviations for these vertebrae are T1, T2 through T12. The rib cage is also secured to the thoracic spine as the 12 pairs of ribs attach posteriorly (in the rear) to each thoracic vertebrae. These vertebrae are larger in size than those in the cervical spine as they provide more anchoring for posture.

Lumbar spine - The lumbar spine has five vertebrae respectively numbered L1 through L5. These are the largest bones of the spine because they’re designed to carry the most weight and offer the most stability. There is more range of motion in this region than in the thoracic spine, but less than the cervical spine. The main motion here is flexion/extension (bending forward/backward).

Sacral spine - The sacral spine is five bones fused together that are set between the two bones of the pelvis. Combined with the coccyx -- which is composed of five fused bones that create the tailbone -- the sacral spine provides a base on which to sit and offer stability to the pelvis itself.

Proper function and motion of the spine is necessary for optimal communication within the nervous system. Lack of proper function and motion can have a significant effect on your health and well-being in ways likely beyond what you’re aware of.

See a chiropractor, get evaluated, and discover how the health of your spine may (or may not) be affecting your quality of health and life.

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