Modern ultrasound devices not only provide excellent services in gynaecology, but are also used in orthopedics for examining muscles, ligaments and tendons. They work with sound waves whose frequencies are far above the human hearing ability and are emitted as sound wave pulses via an ultrasonic probe. These are reflected to different degrees in the tissue layers, so that the tissue structure can be displayed in different shades of gray by the ultrasound monitor. A major advantage over X-rays is the absolute absence of radiation, which is why ultrasound examinations are completely harmless.
