Ultrasound therapy is a type of thermal treatment that helps relieve some types of acute and chronic pain. Therapeutic ultrasound is typically delivered at frequencies between 0.8 to 3 megahertz. Lower frequency provides deeper penetration, up to about 2 inches. The sound waves cause molecules in the tissues to vibrate, producing heat and mechanical energy. This allows for deep heating of tissues such as muscles, tendons, ligaments, joint capsules and bone. The thermal effects of ultrasound therapy have been found to be beneficial in the treatment of musculoskeletal injuries, breaking down scar tissue and helping to stretch tendons. The use of ultrasound as deep heat therapy may also be accompanied by electrical stimulation of the muscle. This results in mechanical pumping, which would promote the removal of products of increased metabolism, and treat muscle spasms and microscopic tissue adhesions. Therapeutic ultrasound may be used to treat many other conditions as well. It has anti-inflammatory effects that can relieve the pain and stiffness of arthritis, myofascial pain, fibromyalgia, bursitis, carpal tunnel syndrome, phantom limb pain, sprains, and strains. Many people ask, “What does ultrasound feel like?” You may feel a gentle pulsing or a slight warmth under the skin. Many people do not feel anything at all except for the soothing gel. It may be used to treat impingement or compression of nerve roots and various types of nerve inflammation and may be useful in the care of post-traumatic injuries.