The method used by physicians to determine, by listening, the condition of certain internal organs.

In 1819 the French physician, Laennec, introduced the method of auscultation by means of the STETHOSCOPE. Initially a wooden cylinder, the stethoscope has evolved into an instrument consisting of a small expanded chest-piece and two flexible tubes, the ends of which fit into the ears of the listener. Various modifications of the stethoscope have been introduced, including teaching stethoscopes which amplify the sound so students can hear what the examiner has detected.

Conditions affecting the lungs and heart can often be recognised and categorised with the help of auscultation and it is also helpful in the investigation of aneurysms (see ANEURYSM) and certain diseases of the OESOPHAGUS and STOMACH. The stethoscope is also a valuable aid to the health of the fetus during labour.