One of the benefits of therapeutic ultrasound is that it can be provided in an "indirect" fashion - particularly on parts of the body that are very small or irregular in contour. One of my favorite examples is one that I demonstrated in the recent webinar on Ultrasound - the Difference Between Diagnostic and Therapeutic Ultrasound (the focus was on musculoskeletal and soft tissue injuries / disorders).
This bird had become disabled as a result of being provided improper perching rods in its cage. It is difficult to place an ultrasound head against the small and irregularly contoured leg of a bird. This video demonstrates that the therapy can be provided indirectly, by way of immersion in a water bath. The treatment resulted in relaxation of the muscles of the bird's feet. This allowed for the feet to be stretched back into a more normal position so that it could once again stand and perch.
The main difference in therapeutic effect when comparing traditional hot compresses with therapeutic ultrasound is depth of penetration. Traditional hot compresses typically heat the skin and subcutaneous tissues to a depth of 1 -2 cm. Therapeutic ultrasound can heat at depths between 2 and 5 cm.