Inspired by his paper experiment, he built several hollow wooden prototype instruments attached to a single microphone at one end and earpiece at the other, and named it the stethoscope.

The term is derived from the Greek words 'stethos' for chest, and 'scopos' for examination.

The evolution of the stethoscope

The instrument was swiftly adopted across France and wider Europe, before spreading to the US. Laennec died of tuberculosis aged just 45 in 1826, but was aware of the importance of his discovery, calling it "the greatest legacy of my life."

In 1851 Irish physician Arthur Leared invented a binaural stethoscope, which fitted into both ears, made of a durable plastic called gutta-percha. The first commercially available instrument, made of India rubber and wood, was patented the same year by Doctor Nathan Marsh of Cincinnati. Unfortunately it was too fragile to be used properly.

The next year New York-based doctor George Cammann successfully adapted the design for wider commercial production, made of ivory earpieces connected to a metal tube held together by a hinge. Known as Cammann's Stethoscope, variations of the design have remained in use ever since.

Cammann never patented his design because he believed it should be freely available to all doctors.

How to use a stethoscope