Therapeutic ultrasound is a treatment modality commonly used in physical therapy. It is used to provide deep heating to soft tissues in the body. These include muscles, tendons, joints, and ligaments. Ultrasound in physical therapy is not to be confused with diagnostic ultrasound, which is an ultrasound that is used to see the inside of the body, such as checking on a fetus during pregnancy.
What Does Ultrasound Do?
Deep heating effects
Ultrasound is often used to provide deep heating to soft tissue structures in the body. Deep heating tendons, muscles or ligaments increase circulation to those tissues, which is thought to help the healing process. Increasing tissue temperature with ultrasound is also used to help decrease pain.
Deep heating can be used to increase the “stretchiness” of muscles and tendons that may be tight. If you have shoulder pain and have been diagnosed with a frozen shoulder, your physical therapist may use ultrasound to help improve the extensibility of the tissues around your shoulder prior to performing range of motion exercises. This may help improve the ability of your shoulder to stretch.
Non-thermal effects (Cavitation)
Ultrasound introduces energy into the body. This energy causes microscopic gas bubbles around your tissues to expand and contract rapidly, a process called cavitation. It is theorized that the expansion and contraction of these bubbles help speed cellular processes and improves healing of injured tissue.
How Is Ultrasound Applied?
Ultrasound is performed with a machine that has an ultrasound transducer (sound head). A small amount of gel is applied to the particular body part; then your physical therapist slowly moves the sound head in a small circular direction on your body. The therapist may change various settings on the ultrasound unit to control the depth of penetration of the ultrasound waves or change the intensity of the ultrasound. Different settings are used in various stages of healing.