15. Stethoscope

Physicians as early as Hippocrates, used to listen to the heart and lung sounds, by placing their ears directly on the chest of the patient. They would use a handkerchief to avoid direct contact with the chest.

One day in 1816, a French physician Laennec observed children playing with a long hollow stick. He was amazed to notice that the minute sounds made in one end of the stick were amplified and transmitted to the other end.

Subsequently he had to listen to the chest of a young woman. Instead of placing his ear on her chest, he rolled several sheets of paper into a cylinder and listened through it. He was thrilled that he could hear the heart and lung sounds much better than ever before.

He later used a wooden cylinder instead of the paper roll. He named his invention as Stethoscope derived from the Greek “Stethos” for chest and “skope” for examination. He made a portable version with three pieces which can be dismantled and reassembled quickly.

Several improvements have been made on these simple cylinders subsequently. The first Binaural stethoscope with two ear pieces was made by George Cammann in 1852.

In 1894, Robert Bowles introduced the first diaphragm based stethoscope. In 1940, doctors Sprague and Rappaport introduced the two sided chest piece to listen to sounds of different frequencies.

In 1960s David Littmann redesigned the stethoscope with a single tube which had two internal channels and further refined the device.

In the 1990s electronic stethoscopes were produced. The latest version released by 3M-Littmann has Blue tooth capability that transmits heart sounds to a computer for software analysis.

We have come a very long way, but it all started with the modesty and curiosity of a French physician!

Visalakshi Ramani