What is the speed of sound in muscle tissue?

• A. 1,560 m/s
• B. 1,600 m/s
• C. 3,500 m/s
• D. 1,700 m/s

Answer: (B)

The speed of sound in tissue reflects how stiff the tissue is and how dense it is. Muscle is a soft, moderately stiff tissue with density close to water, so waves travel a bit faster than the very softest tissues but well below the speeds seen in bone. In ultrasound practice, a standard estimate for soft tissues like muscle is about 1,600 meters per second, with minor variation depending on temperature and fiber orientation. That makes the 1,600 m/s option the best match for muscle. The other values are less representative: around 1,560 m/s is plausible for some soft tissues but not the common muscle standard; 3,500 m/s is typical of bone or very stiff materials; 1,700 m/s is higher than the usual muscle range.