If the speed of sound in a medium is less than the average speed of...

The placement of an echo on an ultrasound image is dependent on the assumption that the speed of sound in soft tissue is 1540 m/s. If the speed of sound in the medium is less than this assumed speed, the ultrasound system will interpret the returning echo as taking longer to return than it actually does. This causes the system to place the echo deeper in the image than its actual position. Therefore, the echo will be displayed "too deep" in the image.