Ultrasound is just sound above frequencies that humans can hear, which is a vast range from ~20khz up to practical physical limits, gigahertz at least. Your bod

Ultrasound is just sound above frequencies that humans can hear, which is a vast range from ~20khz up to practical physical limits, gigahertz at least. Your body has resonant parts that can be damaged by frequencies in the _audible_ range, the chief parts being in your ears but other parts, too, if the sound is sufficiently loud, e.g. a shockwave from a powerful explosion. So amplitude (volume) is clearly very important. All that to say, I don't think there's any cause here to draw suspicion upon sonograms or other time-tested procedures.