Ultrasound waves sent to the part of the body being examined are reflected, refracted, or absorbed at the interfaces inside the body. Echoes that return in this way carry information about the size, distance, and uniformity of internal organs. This is displayed on a monitor to create an ultrasound image. During abdominal sonography, a hand-held device called a “transducer” is placed on the area being examined and moved around. This transducer generates ultrasound and sends it through the body. It also detects the returning echoes and transmits them as electrical signals.