Close relationships among trigger points, acupuncture points, and tender points. Trigger points in patients with myofascial pain syndrome appear close to those of acupuncture points. TP1-5 around the knee joints (bottom left figure) were very similar to acupuncture-point loci. The diagnostic tender points for fibromyalgia patients (dots in the bottom right figure) were also very similar to acupuncture-point loci. Referred pain phenomena might be a possible explanation of meridian (center of bottom figures).