Ultrasound is primarily useful as a deep as a deep heating agent at present because it produces a rise of tissue temperature in selective areas requiring heat for therapeutic purposes. There are many factors influencing the temperature distribution in areas exposed to ultrasound but standardized criteria are lacking for sites in human beings, especially in scapular area.

Sixteen patients suffering from myofascial pain in shoulder area recieved ultrasound at the intensities of 0, 0.5, 1.0, 1.5, 2.0 W/cm² for 10 minutes in infraspinous fossa. tissue temperatures were recorded near the interface between scapular bone and infraspinatus muscle (depth: 3-5 cm) using clinical thermomerer.
Results
are followings.

1) Ultrasound at an intensity of 1, 0.5(0) W/cm² caused the decrement of tissue temperature at a rate of 0.01^oC/mim for 10 minutes (p<0.05)

2) Tissue temperaturerose at a rate of 0.05, 0.09, 0.17, 0.26^oC/min. for 10 minutes with 0.5, 1.0, 1.5, 2.0 W/cm² respectively (p<0.05).

3) All patients that received the ultrasound of 2.0 W/cm² reported warm sense but the beginning points of warm sense are of wide range, ranging from 37.4^oC to 40.2^oC (average 39.0^oC). Patients generally felt warmth when they received 1.5 W/cm² intensity, at the speed of 3-4 sec/circle.

4) Minimal conditions of ultrasound therapy in infarspinous muscle area should preferably be 10 minutes in duration, 1.5-2.0 W/cm² in intensity, in moderately slow stroking method.