Stethoscope

The stethoscope is a medical device used to listen to internal body sounds - the beating of the heart, the movement of air in and out of the lungs, gut sounds from the stomach and intestines, and even the heartbeat of a foetus. A traditional (binaural) stethoscope is built around a disc-shaped resonator, or chest-piece, which is pressed against the patient's chest or back; the resonator picks up faint internal vibrations and channels them along two flexible rubber tubes to a pair of earpieces worn by the examiner. Because it works purely on trapped and amplified sound, the acoustic stethoscope needs no batteries or electronics, which is part of why it has remained in daily use for two centuries. The modern electronic stethoscope improves on this basic design by electronically amplifying the captured sound, so a clinician can hear clearly even in a noisy ward or through a patient's heavy clothing. Clinically, the stethoscope is used to detect normal versus abnormal heartbeat sounds and to assess how well the heart valves are working; to pick up lung sounds that indicate diseases such as pneumonia, pulmonary oedema, bronchitis and pleuritis; together with a sphygmomanometer, to time the sounds …