What Causes the Imbalances of the Spine In Scoliosis?
Scoliosis results in alteration of the bones of the spine and rib cage, but what makes this to happen?
Afterall, the bones do not move themselves, muscles move them. Muscles of of course only react to how the nervous system instructs them to move. Even though the most common cause of scoliosis is unknown (ideopathic) there is still SOMETHING that causes it to happen.
This post seeks to explore the factors that are known to play a part in scoliosis causes.
A constant interplay of muscles, nerves and fascial tension should result in a balanced structure which keeps the head evenly over the shoulders, which are centered evenly over the hips, knees and ankles. Additionally, when balanced the joints on both the right and left side of the body should be at right angles to each other and in the same plane as the horizon. Any deviation from this structurally sound position will result in the development of degenerative changes over that are the body's attempt to stabilize the area. These structural abnormalities along and associated degenerative changes will eventually result in pain and disability.
Scoliosis results in a severe imbalance in the structural integrity of the body that overtime causes the owner of the body progressively more and more problems. For them, regaining as much structural balance as possible is critical to preventing further degenerative changes and pain.
Let's examine the components of the body that are frequently found to be out of balance in scoliosis. Structures involved in respiration (the diaphragm, muscles of the rib cage, deep postural muscles of the spine and muscles involved in rotation of the body overall will be adversely affected in scoliosis. The imbalances of these muscles and their related muscle groups cause the unilateral rotation dysfunction of the spine that is characteristic of most scoliosis cases.
Muscles surrounding the spine greatly affect its shape and movement. In his book called Anatomy Trains - Myofascial Meridians for Manual and Movement Therapist author Thomas Myers discusses interconnected lines of functional muscle chains that he calls "Anatomy Trains". The colored lines (also known as kinestic chains) on the cover of his book show the direction of the different muscle chains.
These functional chains of muscles are interconnected to each other by way of a fascial network (fascia is the web like substance found between the muscles, bones and nerves) and shared bony attachments. Each group helps perform specific movements in the body. He furthers a concept called "tensegrity" and applies it to the chains of muscles in the body he calls Anatomy Trains and further states that they must maintain an overall tension along the line to keep the body balanced. (1) If any lack or over abundance of tension in one part of the line occurs then muscles in the other parts of those chains or ones in an antagonist group must take up the slack or release it.
With scoliosis the primary kinesthetic chains affected is the Spiral Lines in the body. One of these lines has shortened and become fibrotic overall, the other has become over stretched and weakened. This results in an overall rotation dysfunction of the body. The dysfunction occurs when muscles in the line on one side of the body becomes overly shortened and taut while the other becomes overly stretched and painful, resulting in a loss of the person's overall bifunctionality (if the body is balanced then the right and left sides should be able to do the same thing).
Spiral Lines are pairs of mirrored lines that wrap around the body in a helix and serve to maintain balance across the body and aid in rotation movements of the body. The larger muscles of this group run from the base of the skull to the top two vertebra in the spine, to the muscle sin the neck, across to the muscles beneath the opposite shoulder blade, to the core abdominal muscles on the side of the back that wrap around and attach to the others on the opposite side of the abdomin and attach to the front of the hip on the other side. Although this same line continues on into the lower extremity in same fashion, I will end the discussion here for the scope of this article being limited to the spine.
When one of these lines becomes taut and shortened it creates an imbalance that maintains a rotational torque in the body along the axis of the spine. The eventual torsion buckling of this crooked spine causes the lateral shift which serves to further enhance a scoliosis pattern in the spine. (See Illustration - (2))
Soft tissue work, therapeutic movements or ones sided activities that lead to a further spiraling causes the kinesthetic chains to mal-adapt further worsening the rotation dysfunction and adds to worsening of the curvatures.
In compensation, the muscles in the opposite spiral line become stretched and due to the prolonged tension on the proprioceptive fibers and they become overly strained and often eventually painful while trying to contain the curvature. This cause's extreme torsion and strain to the body that has an impact on the muscles that surround the spine and cause a corkscrew scoliosis curve.
To help restore the person's bifunctionality and return overall balance to the spine you first must release the tension in the muscles of the shortened spiral line so as to take off the strain to the opposite spiral line. Once this is achieved THEN the process of structural re-balancing can begin.