Laënnec, René Théophile Hyacinthe

[laynek] (1781–1826) French physician: invented the stethoscope.

Laënnec studied at the Charité hospital in Paris and qualified as a doctor in 1804. Despite ill-health he did much to advance clinical diagnosis and his writing on disease is modern in approach. It was well known that listening to chest sounds (auscultation) was useful in diagnosis, and tapping the chest (percussion) had been shown by J L Auenbrugger (1722–1809), in 1761, to be informative also.

In 1816 Laënnec met a difficulty in hearing the heart action of a plump and shy young woman, and solved it by connecting his ear to her chest with a paper tube. He was surprised to find that the heart sounds were then louder and clearer. He soon replaced his paper tube with a wooden tube 30 cm long–the first stethoscope. It was not until the end of the century that the binaural stethoscope, with rubber tubes to both ears, replaced the simple tube in general use and became the physician’s most readily identifiable instrument. Laënnec was able to link chest sounds with a range of diseases, mainly of the heart and lungs, and described his results in his book On Mediate Auscultation (1819). He was an outstanding clinician.