Thoracic Outlet Syndrome

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Causes of Thoracic Outlet Syndrome
Acquired sources of thoracic outlet syndrome include muscle tightness or hypertrophy (enlargement) of the anterior and medial scalene muscles on the side of your neck. Reduction of the small space between these two muscles compresses the brachial plexus and can cause symptoms associated with TOS.

Another cause of thoracic outlet syndrome is poor posture that results from strength imbalances or hypertonicity of the pectoralis minor muscle (a very tight pectoralis muscle)—two issues that can pull the shoulder downward and forward, placing pressure on the nerves of the brachial plexus.

Also, an over-exaggerated straight posture, known as military posture, pulls the clavicle backward, which can impinge the nerves and/or blood vessels.

Structural or anatomical sources of thoracic outlet syndrome include an additional rib, or cervical rib, located above the first rib, that places pressure on the nerves.

Less commonly, wider than normal shoulder ligaments may also elicit compression of the nerves.

Thoracic Outlet Syndrome Diagnosis
If you begin to experience TOS-like symptoms, see a medical professional immediately to rule out a more serious pathology. Your doctor will perform an extensive consultation and examination to determine the exact source of your condition, your diagnosis, and your course of treatment. Diagnostic studies, such as x-rays, magnetic resonance imaging (MRI), and nerve conduction velocity testing, may be recommended.

Updated on: 12/22/10
Mitchell F. Miglis, DC

This article mentions some key points, but here are a few additional important things to keep in mind about thoracic outlet syndrome (TOS):

TOS is thought to arise from one of two predominant mechanisms: nerve compression or blood vessel compression. Thus, TOS is divided into two broad syndromes—those which produce mostly neurologic dysfunctions and those which produce mostly vascular dysfunctions. Sorting the two syndromes is clinically challenging and not always possible, but, nevertheless, TOS may be mostly neurologic or mostly vascular in etiology.

There's also another cause of TOS I'd like to mention: Rarely, but importantly, thoracic outlet syndrome is the result of a serious underlying disorder. An example of this is tumors in the upper lung, which can compress either the nerves or blood vessels of the thoracic outlet, producing symptoms of TOS.

I would also like to point out that while certain treatments, such as chiropractic and yoga, can be effective for treating TOS, there is no scientific evidence that GYROTONIC exercises are helpful in treating TOS. In addition, GYROTONIC exercises appear to require proprietary and potentially expensive equipment.

Donald A. Ozello, DC
Dr. Ozello's response to Dr. Miglis' comments:

When TOS-like symptoms arise, a more serious pathology must always be ruled out as the source.

Nerve slide exercises are simple exercises that one can learn from a trained medical professional and perform anytime during the day.

GYROTONIC exercise must be taught and supervised by a trained professional using specific equipment.