The presence of a myofascial trigger point (MTrP) is a controversial subject. One of the reasons is that there are no objective laboratory tests for diagnosing MTrPs. Ultrasound (US) is a reliable tool that allows for real-time scanning of the targeted myofascial structure. However, B-mode US failed to visualize soft-tissue changes in the region of clinically identified active MTrPs. Although it was reported that sonoelastography could distinguish myofascial tissue containing MTrPs from normal myofascial tissue, it has several limitations including difficulty of pressure and angle control. US for diagnosing MTrPs is challenging. However, a recent study suggested that US-guided trigger point injection may improve the detection rate of local twith responses (LTRs) and the therapeutic efficacy of trigger point injection for MTrPs in deeply located muscles in patients with myofascial pain syndrome. In addition, US-guided trigger point injection into an MTrP is expected to improve injection accuracy and reduce potential inadvertent injuries made by an improperly placed needle. (Clinical Pain 2012;11: 0-71)

KeywordsMyofascial pain syndrome, Trigger points, Ultrasound, Elastography