Fibromyalgia, myofascial pain, tender points and trigger points: splitting or lumping?

The paper by Ge and colleagues from the Center for Sensory-Motor Interaction at Aalborg University, Den-mark provides evidence that peripheral nociceptive input from muscle may be relevant to the contemporary understanding of fibromyalgia (FM) [1].This study involved asking each subject (both FM patients and controls) to draw all areas of current spontaneous pain on an anatomical map and rate the overall intensity of pain. The area of pain was quantified by digitization software. The location of all active myofascial trigger points (MTPs) was then determined in the FM subjects using clinical palpation [2]. Altogether 308 active MTPs were found in the 30 FM subjects, and 305 of these were confirmed by the demonstration of spontaneous electrical activity on needle electromyography (EMG). The locations of these 308 active MTPs were then mirrored onto the 30 healthy controls as an aid to identifying latent MTPs; spontaneous electrical activity was found in 304 of these latent MTPs. The major MTP in each muscle was manually palpated at a pressure of about 4 kg for 10 seconds, and the location and area of referred pain was drawn by the subject and later digitized for subsequent analysis.The major findings were as follows. The intensity of the spontaneous pain in FM was strongly correlated with the total area of pain referred by manual palpation of MTPs. Manual stimulation of active MTPs in FM produces a local and referred pain pattern that is similar to the subject's current spontaneous pain report. The locations of active MTPs in FM subjects were generally found to be the site of latent MTPs in the controls. The overall number of MTPs was similar in both the FM patients and control subjects, but FM subjects had active MTPs whereas the controls' MTPs were latent. Active MTPs in the FM subjects were most commonly found in the extensor digitorum, trapezius and infraspinatus in the upper body, and in the quadratus lumborum and gluteus medius in the lower body.A critical issu