Stethoscope. View of a stethoscope hanging out of a pocket on a white coat. It is an instrument used to listen to noises made in the body by the heart, lungs and digestive system. A stethoscope is made up of two earpieces (upper right), a connecting tube, and a round sound-detecting device (lower centre). The sound-detecting device has a wide diameter diaphragm to listen to high-pitched sounds, and a smaller concave bell side to listen to low-pitched sounds. Internal noises can be heard by pressing the device against a patient’s body. A stethoscope helps diagnose respiratory ailments of the lungs, abnormalities of the heart, and movements in the digestive system.