stethoscope (stĕthˈəskōpˌ) [key] [Gr., = chest viewer], instrument that enables the physican to hear the sounds made by the heart, the lungs, and various other organs. The earliest stethoscope, devised by the French physician R. T. H. Laënnec in the early 19th cent., consisted of a slender wooden tube about 1 ft (30 cm) long, one end of which had a broad flange, or bell-shaped opening. When this opening was placed against the chest of the patient, the physician, by placing his ear against the opposite opening, could hear the sounds of breathing and of heart action.
The stethoscope changed little until the beginning of the 20th cent. when the binaural instrument was developed by G. P. Cammann, a New York physician. It consisted of two earpieces with flexible rubber tubing connecting them to the two-branched metal chest cone. Thus the sounds could be heard with both ears, and the instrument's flexibility permitted the physician to listen to various areas without changing his position. Electronic stethoscopes make it possible for several clinicians to listen at the same time to the sounds emitted by a particular organ.
Stethoscopy (also called auscultation), used together with percussion (light tapping of the chest), is a fundamental diagnostic measure in medical practice. The qualities of the sounds emitted by the lungs and heart denote the health or abnormality of these organs. Many diseases of the heart and lungs, and sometimes of the stomach, blood vessels, and intestines, can be recognized early by skillful use of the stethoscope.
See study by M. D. Blaufox (2001).