Sound travels in waves. Ultrasound is sound which travels at a higher frequency than we can hear.
Ultrasound examinations known as scans are done by building up pictures from the return of sound waves as they bounce back from any resistance they meet. The sound waves can be directed to and bounced back from the surfaces of various structures within the body to form pictures on a television screen.
The ultrasound waves are sent to and from the body by moving a hand-held sensor which is similar to a microphone over the surface of the skin of the area to be examined. Pictures, known as images are taken for doctors and senior radiographers look at them and diagnose your condition.
Ultrasound scans can be used to diagnose a variety of conditions. They are also used to guide the position of needles for injections.