What is Ultrasound?
Ultrasound is used to provide deep heating to soft tissues in the body. These tissues 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?
Therapeutic ultrasound is used primarily for two different effects: the deep heating treatment and non-thermal uses.
Deep heating effects: Ultrasound is often used to provide deep heating to soft tissue structures in the body. Deep heating tendons, muscles or ligaments increases 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 theorised that the expansion and contraction of these bubbles help speed cellular processes and improves the healing of injured tissue.
How Does Ultrasound Work?
Inside the ultrasound unit is a small crystal. When an electrical charge is applied to this crystal, it vibrates rapidly, creating piezoelectric waves. These waves are emitted from the ultrasound sound head as ultrasound waves. The ultrasound wave then enters into your injured tissues during application of the modality. This increases blood flow and cavitation, leading to the theorised benefits of the treatment.
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 the sound head is slowly moved in a small circular direction on your body. The settings of the ultrasound unit can be changed 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.
What Ultrasound Feels Like
While you are receiving an ultrhsound treatment, you will most likely not feel anything happening, except perhaps a slight warming sensation or tingling around the area being treated.
Common Injuries Treated With Ultrasound
Usually, orthopedic injuries are treated with ultrasound. These may include:
Generally speaking, any soft-tissue injury in the body may be a candidate for ultrasound therapy. It can be used for low back pain, neck pain, rotator cuff tears, knee meniscus tears, or ankle sprains.