Myofascial Pain Syndrome and fibromyalgia may coexist, presenting a complex clinical picture; however, fibromyalgia and myofascial pain syndrome are not one and the same condition. Fibromyalgia is a generalized amplification of pain or hypersensitivity condition and is associated with tender points in the muscles. Tender points are focal areas of muscle tissue that are exquisitely tender to compression. The tender points of fibromyalgia are painful locally at the site where the pressure is applied, without referred pain to distant areas.
By contrast, myofascial pain syndrome is considered in the narrow definition to be a disorder of trigger points. Similar to tender points, trigger points also are discreet areas in muscle tissue and/or its associated fascia that are exquisitely tender to compression; however, unlike tender points, when pressure is applied to the trigger point, pain occurs not only at the site of the applied pressure, but also at a distant site (zone of pain referral). Trigger points are found in taut bands (firm elongated bands) within the muscle fibers and are associated with the local twitch response. This local twitch response is an involuntary transient contraction of the taut band muscle fibers and can be elicited by snapping or pinching the taut band. Some authors assert that both disorders (fibromyalgia and myofascial pain syndrome) can magnify and perpetuate the symptoms of the other.
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Myofascial Pain Syndrome – – International MYOPAIN Society – http://www.myopain.org/