Spinal Anatomy Overview
The spine is a complex collection of bones that provides the main support for the human body. It is designed to be very structurally supportive and yet very flexible. The spine is a collection of 33 bones, all moving together in perfect harmony when in good structural alignment. Your spinal column also has a very important job of protecting the spinal cord and all of the nerves exiting out the spine which connect your brain to your body parts. By reviewing spinal anatomy, patients can understand the importance of a healthy spine and better benefit from chiropractic adjustments.
Normal Spine Alignment
The spine, from front to back, should appear as a straight line. Curvatures, if significant enough, can be considered scoliosis. From the side, the spine does have some important curves. The curve in the neck (cervical) and lower back (lumbar) are called lordotic because they have a concave curve that opens toward the back. The middle back (thoracic) and sacral regions have a mild convex curve that opens toward the front of the body. These curves are extremely important because they allow the spine to absorb shock and maintain good balance, as well as allow for a good range of motion between each vertebra of the spinal column.
Learn about the parts of a Healthy Spine.
The neck is made up of the first 7 bones in the body, which are labeled C1-C7. They provide support for the neck and allow for a great range of motion for the head. The first vertebra (C1) is known as atlas because it supports your world (your head) just as the Greek god Atlas supported the world. It is ring-shaped and connects via muscles and ligaments to the skull to allow for a “yes” movement of the head. The atlas also connects to the second bone (C2) and has an upward projection called the odontoid process that lets the atlas pivot around. This creates the “no” movement of the head.
Many chiropractors only focus on this area of the spine because it is vitally important. Directly in the center of these bones is the downward projection of the brain, called the brainstem. Even the slightest misalignment of the spine in this region could put stress on the brainstem, affecting not only structures in the surrounding area but in the entire body due to the neurological connections extending down from this area.
The main role of the thoracic spine is to support the rib cage. It also protects the heart and lungs, as well as the spinal cord in the center of the back. There are 12 vertebrae in this region labeled T1-T12.
Lumbar (low back)
The main function of the lumbar spine is to support the weight of the upper torso. The five lumbar vertebrae are labeled L1-L5. You will notice that these vertebrae are larger than the others because of the tremendous amount of stress they support.
The sacrum connects the spine, specifically the axial portion of the body, to the hips and what is referred to as the appendicular portion of the body. There are 5 sacral vertebrae that fuse together as you get older.
This region is made up of 3-5 fused bones and provides an area for many ligament and muscular attachments that make up the pelvic floor.
In between most vertebra is a vertebral disc. The vertebral discs are made up of an inner gel-like portion called the nucleus pulposus. This is designed to cushion as well as provide separation between the vertebrae. The outer fibrous layer is called the annulus fibrosis and provides support for the discs. There are no vertebral disks between the skull and C1, C1 and C2, and the fused vertebrae in the sacrum and coccyx.
The Spinal Cord
The spinal cord is the downward extension of the brain. It is extremely important and often overlooked. The spinal cord communicates the brain’s messages to all of the organs, tissues, and cells in the body, allowing you to function. The reason chiropractors work on the spine is because of this delicate and powerful organ.
Without a healthy spinal cord, the body can never function at its optimal level. Chiropractors look at the spine to determine if there is any interference or dysfunction causing neurological interference. When these areas, called subluxations, are located, a chiropractor will use a specific, scientific force to remove them, thus restoring optimal function to the spine.