Dr Janet travel coined the term trigger point in 1942 to describe clinical findings with characteristics of pain related a discrete irritable point in muscle or fascia that was not caused by acute trauma, inflammation, degeneration, neoplasm or infection. The painful point can be palpated as a nodule or tight band in the muscle that can produce a local twitch response when stimulated. Palpation of the trigger point reproduces the pain and symptoms of the patient and the pain radiates in a predictable referral pattern specific to the muscle harbouring the trigger point.