Musculoskeletal ultrasound (MSK ultrasound) is a non-invasive and safe imaging procedure that uses high-frequency sound waves to produce pictures of muscles, tendons, ligaments, nerves, and joints throughout the body. It is used to help diagnose a wide range of injuries and chronic conditions, including muscle tears, tendonitis, bursitis, joint problems, rheumatoid arthritis, and masses such as tumors or cysts. MSK ultrasound can also help determine the source of muscle or joint symptoms, such as a lump, and assess how well injuries are healing. During the procedure, a hand-held scanning device called a transducer is pressed on the skin, and the transducer sends out inaudible, high-pitched sound waves that travel through the body. The sound waves bounce back and are collected by the transducer, which sends them to a computer that creates an image based on the loudness and travel times of the sound beams. MSK ultrasound is particularly helpful in the diagnosis of orthopedic and sports injuries such as rotator cuff tears, and chronic conditions such as rheumatoid arthritis. MSK ultrasound has the added advantage of being radiation-free and not requiring an injection of a contrast agent.