Myalgia is pain originating in the muscles of mastication and differs from TMJ pain in several ways. Myalgia is only loosely correlated with jaw function, whereas joint pain is a direct function of joint movement. Myalgia is typically delayed in onset. The muscle pain from myalgia is more diffuse and slowly waxes and wanes over time.
Myofascial pain syndrome (MPS) is a form of myalgia that is characterized by local regions of muscle hardness that are tender and that cause pain to be felt at a distance, i.e., referred pain. The central component of the syndrome is the trigger point that is composed of a tender, taut band. Stimulation of the band, either mechanically or with activity, can produce pain.
Clinical diagnosis of a MPS is made by history and by palpation of muscle to identify the taut band. Predisposing and perpetuating factors such as iron insufficiency, vitamin D deficiency, and chronic pelvic pain are considered and addressed if found. The goal is to eliminate the trigger points, reverse trigger point-induced weakness and incoordination, and restore normal muscle function. Manual trigger point releases, and needling the trigger point, without or with local anesthetic, and use of low-level laser are effective ways of inactivating trigger points and reducing pain. MPSs can mimic or cause many common conditions such as chronic daily headache