Neuropathic Myofascial Pain Syndromes

The function and integrity of all innervated structures are contingent on the flow of nerve impulses in the intact nerve to provide a regulatory or ‘trophic’ effect. When this flow (probably a combination of axoplasmic flow and electrical input) is blocked, innervated structures are deprived of the trophic factor which is necessary for the control and maintenance of cellular function. ‘A-trophic’ structures become highly irritable and develop abnormal sensitivity or supersensitivity according to Cannon and Rosenblueth’s Law of Denervation ... The importance of disuse supersensitivity cannot be overemphasized. When a nerve malfunctions, the structures it supplies become supersensitive and will behave abnormally. These structures over-react to many forms of input, not only chemical, but physical inputs as well, including stretch and pressure.