Who Invented the Stethoscope?

Stethoscopes have been vital diagnostic tools for, and symbols of, the medical profession for more than 200 years. Where did they come from?

The idea of diagnosing diseases by listening to the sounds a patient’s body makes, known as auscultation, dates to ancient Greece. But the need for a medical professional to place his or her ear directly on a patient’s chest to listen to heartbeats, breathing, and assorted digestive gurgles was unappealing for several reasons.

For instance, a patient’s obesity could muffle important noises. No physician was eager to press against a filthy patient who, in some cases, could have lice. And a male doctor might be hesitant about getting too close to a female patient.

It was this last modesty-related challenge that, in 1816, inspired French doctor Rene Laennec to invent the stethoscope. Laennec, working in a Paris hospital, was reluctant to press his ear against a female patient’s chest. He rolled several sheets of paper into a tube and tried to listen to her heartbeat.

Laennec realized the tube not only amplified her heartbeat and breathing — the sounds were louder and clearer than he would’ve been able to discern by direct auscultation.

Laennec, 27 at the time of this discovery, had long been a medical prodigy. The nephew of a medical school dean, young Rene was caring for sick and wounded soldiers at the age of 14 and had become a military surgeon as an 18-year-old.

He was also a skilled wood craftsman, and refined his rolled-up paper invention into a wooden tube, about a foot long, with a thin end for the doctor’s ear and a wider funnel-shaped opening for pressing against the patient. He called the invention the “stethoscope” after combining Greek words for “chest” and “explore.”

Three years later, Laennec was selling stethoscopes along with a manuscript explaining how to use the new device. Over the next few years, European doctors would travel to Paris to learn from Laennec, who first documented the sounds associated with diseases including tuberculosis, pneumonia, emphysema, and others.

Unfortunately, when Laennec contracted tuberculosis, he understood the seriousness of his condition as an assistant described the sounds he could hear within Laennec’s chest. Laennec died in 1826 at the age of 45.

Stethoscope Improvements

Laennec’s wooden tube stethoscope remained largely the same until the invention of rubber tubing transformed stethoscope design. In 1851, Irish physician Arthur Leared invented the binaural stethoscope, which included two earpieces to block outside noise and to amplify internal sounds. The next year, New York doctor George Cammann, who had studied auscultation in Paris, refined and commercialized Leared’s design.

The next major stethoscope advance came in 1925 when Harvard cardiologist Howard Sprague (an early anti-smoking advocate) and electrical engineer M.B. Rappaport developed the two-sided bell and diaphragm design. The narrow bell is best suited for detecting low-frequency sounds, such as heart murmurs. The wider diaphragm is best for listening to breathing, heartbeats, and the digestive system.

In 1960, Harvard professor and cardiologist David Littmann created a stethoscope with a tunable diaphragm and better acoustic performance than was available at the time. He formed a company that was acquired by 3M. In 1999, Dr. Richard Deslauriers invented a recording stethoscope that included noise-reduction features.

Over the past 200 years, Rene Laennec’s idea that doctors could use an external device to listen to the diagnostic clues within their patients’ bodies has proven invaluable to the practice of medicine.