The Atlas: An Introduction

Posted 1 year ago

The Atlas: An Introduction

by Dr. Brad Steinle

The story of Atlas from Greek mythology is widely known today. Even if someone has never heard the story he or she is familiar with the popular image of a man ordered to carry the celestial sphere on his shoulders.  In the anatomy of the human body the noun “Atlas” has a very different definition. However, the function of the human body’s atlas is quite similar.

atlas

The atlas, as it applies to human anatomy, is the very first bone in the spine. First and foremost this bone protects the junction between the brain and the spinal cord (the central nervous system is the only organ in the body that is completely surrounded by bone). While the atlas performs this vital job it must also achieve a high level of mobility. This bone is the reason humans (and a large amount of animals) can flex, extend and rotate their heads; such as shaking “yes” or “no,” respectively.

With all of these duties in mind, it is easy to assume that the atlas is substantial in structure. Instead, the atlas weighs merely 2 ounces in humans, while the average human head weighs anywhere between 9 and 17 pounds. Obviously, the joint formed between the skull and the atlas is of the utmost importance.

 

AtlasAlignment

The natural position of the atlas (excluding few anatomical variances) is orthogonal to the skull and the cervical spine. This simply means that if symmetrical points are chosen on the skull, atlas and cervical spine and intersecting lines are drawn, the lines should form 900 angles to each other.  This allows the greatest room for the brainstem and spinal cord as they exit the base of the skull.

As mentioned before, the atlas must achieve a high level of mobility and in doing so it sacrifices stability. The joint formed between the skull and the atlas is a synovial, diarthrodial joint (freely movable) with a friction coefficient of 0.005. Because of this, it is easy for the atlas to displace away from the orthogonal position. When this happens, postural changes occur in head tilt and rotation, changing the center of gravity in that person and placing additional pressure on structures (such as nerves and intervertebral discs) that are not meant to sustain it.

In order to discover how far the atlas is away from orthogonal, a series of x-rays can be taken to show the extent of movement in three dimensions. A method of adjusting called Atlas Orthogonal has been developed to painlessly and precisely adjust this bone back into the orthogonal position. This is done by use of a table mounted instrument that utilizes a low force percussion wave in order to cause movement of the atlas.

As this is a complex subject, I will continue to write about it in future articles. However, if you are interested in learning more about this technique, schedule an appointment with Advanced Chiropractic and Wellness Center to either discuss, or experience, how beneficial this adjustment can be.

Posted in Well Adjusted Bodies

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