in the United States When the stethoscope is pressed against the body, sound waves make the diaphragm — the flat metal disc part of the device — and the bell-shaped underside vibrate.

Dr Laennec's importance to modern medicine was guaranteed by his invention of the very first stethoscope in 1816. Here are five things you (probably) didn't know about him: 1. Dr Laennec's ...

The modern stethoscope, made of rubber and later plastic, with a bell-like end that is placed on the patient, emerged in the 1890s and since then doctors have rarely been seen without them.