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. Interestingly, this is not the only disorder in which this sequence of events occurs. Asthma, chronic regional pain syndrome, irritable bowel syndrome, possibly multiple sclerosis (as well as a number of others) are all initiated and maintained by this cascade of abnormal nerve reactivity and inflammation (neurogenic inflammation). In all of these, one finds abnormally reactive nerves, glia, mast cells, macrophages, and activated white blood cells perpetuating a dysfunctional vicious cycle. What actually happens in the neurons themselves to cause this activation remains puzzling, but current favorite explanations include up-regulation of SNS-2Na voltage-related receptors and the K-Cl transporter KCC2 as underlying mechanisms. In summary, whether the pain, abnormal sensation, and dysfunction are actually caused by direct trauma or microinjury engendered in repetitive work environments, the central fact of localized inflammation of the nerve, followed by extravasation, fibrosis, and the consequent ingrowth of inflammation-secreting nerves into these adhesive strands, is the central and perpetuating cause for the continued pain and disability, which in turn impinges on all of the adjacent structures in the area above the collarbone, often making them contributory, but secondary, actors in this drama. For more detailed information go to my article "Thoracic Outlet Syndrome as A Disorder of Neurogenic Inflammation".   .