Trigger Points & Myofascial Pain Syndromes

Myofascial pain syndromes are characterized by the presence of hypersensitive areas called trigger points in muscles or the fibrous membrane (fascia) that covers them. Trigger points may originate when muscle tissue is subjected to excessive strain or abrupt stretching. When stimulated, these trigger points cause a specific syndrome of pain, muscle spasms, stiffness and weakness both locally and in distant target areas. This referred pain may occur in seemingly unrelated parts of the body, but the pattern is consistent from person to person. The more common forms of the referred pain syndrome have been mapped anatomically. Once established, trigger points can be activated by often seemingly minor physical or emotional stresses.

Trigger points have been implicated in a variety of pain phenomena, including muscle pain (myalgia), muscular (non-joint) manifestations of arthritis, muscle inflammation (myositis or myofascitis), and inflammation of the white fibrous tissue that comprises muscle sheaths and fascial layers of the whole muscle, joint, tendon, ligament system (fibrositis or myofibrositis). Trigger points, particularly those found in the upper regions of the back and shoulders, are often associated with palpable nodules of fibrous tissue. Physiologically, they form a self sustaining cycle of spasm, pain, more spasm. This vicious cycle may be interrupted at the sensory (afferent) or at the motor part of the mechanism. Trigger point compression, dry needling or injection of an anesthetic solution will intervene at the sensory level, possibly by stimulating brainstem production of enkephalins and endorphins. The result is a palpable softening of tense muscle tissue, signaling muscle relaxation and pain relief which may last for days.