The most important information for the diagnostician comes from the individual’s history. What symptoms were present initially, where they occurred, what made them worse, how and to what parts of the body they spread, and whether or not they affected seemingly unrelated parts of the body are all important. Careful questioning about trivial activities of daily life gives further clues as to the location of the disorder.

The arms, neck, and especially the area above the collarbone need to be examined thoroughly. Two inveterate findings upon testing are: first, an increase of characteristic pain, as well as numbness and tingling, with the passive raising of a straightened arm rotated away from the body; second, a similar increase in symptoms occurring with gentle pressure or tapping in the area above the collarbone. Common findings on inspection will also include swelling above the collarbone, swelling in the hand, a sensitivity to cold accompanied by mottling, and significant thermal asymmetries. Frequently, tenderness at the elbow or wrist with electric-like pain to tapping will occur, and one can often find fibromyalgic-like points about the shoulder blades, at the fascial planes in the arm, in the front of the shoulder at the insertion of the pectoralis minor tendon, and in the chest and back of the head.
The presence of these findings indicates irritation of the large nerve trunks above the collarbone (brachial plexus), which is diagnostic for TOS.

If, in addition, there is either a constant pallor to the hand (which has turned white and possibly has multiple red spots) or gross swelling throughout the hand and arm with a dusty-bluish/purplish tinge, the problem points to a serious disorder of the artery or vein, requiring rapid surgical intervention by a vascular surgeon. The vast majority of cases (95+%) do not show these extreme findings but do show some mild swelling or discoloration, which should not be confused with frank arterial or venous pathology.

One should also bear in mind that other disorders can cause generally similar symptoms and include pathologies at the neck, shoulder, and shoulder blade, as well as the very rare tumor. A variety of systemic diseases can produce these symptoms through other mechanisms that irritate the brachial plexus. Because of this, a thorough blood and imaging workup is a routine requirement and includes analyses for systemic diseases (autoimmune, hormonal, and tumorous), x-ray for both bony and spinal abnormalities, and electrodiagnostics for frank peripheral neuropathies. Magnetic resonance imaging (MRI) of the brachial plexus, using 3-D reconstruction or neurography, can often be helpful in determining localized strictures or deviations of the normal course of the nerves in objectively substantiating abnormalities that point at TOS. Doppler ultrasound, comparing flow with the arm extended and flow with the arm to the side, can also be helpful. Electrodiagnostics are not as helpful, but they rule out other potential causes. I have found thermography to be a very sensitive indicator of abnormal peripheral nerve sensory function/irritation and that it objectively substantiates abnormalities much more frequently than any other imaging modality.

In my own series of over fifteen hundred patients with this disorder, there has been a 14:1 female-to-male ratio. In most other series, this ratio varies from 3:1 to 7:1. This disorder has a clear-cut and, as yet, unexplained predilection for women, which has been variously assumed to be due to work choice, poor posture, large breast size, and a penchant for complaining. None of these, in fact, are entirely convincing, although I should note that women with large breasts and TOS do report a moderate decrease in symptoms following breast reduction.

More important, over 90% of the individuals I have examined are highly motivated perfectionists in the prime of their life and can be characterized as having type A personalities. Their sense of responsibility and commitment to their work activities is, in fact, counterproductive (in the context of TOS) because it encourages the ignoring, or even the frank denial, of their symptoms and often ensures progression of these same symptoms to the point of serious disability.