In 1816, French physician Rene Theophile Hyacinthe Laennec had a young woman on his exam table, and no idea what to do with her. She’d come in complaining of chest pains, and their conversation and the examination up to that point suggested a diseased heart, but Laennec wasn’t sure how he would confirm that.

Since the days of Hippocrates, doctors had limited options when it came to assessing cardiac health, and mainly relied on auscultation, or listening to sounds of the body. Dulled sounds in an area of the chest that was normally more resonant, for example, could indicate extraneous fluid or a tumor. One way of doing this was to place an ear right on the patient’s chest and listen directly to the heart, lungs, and chest cavity. Another option was to tap on the chest or back and listen to the resulting sound, a method developed by an Austrian physician whose innkeeper father tapped on wine barrels to determine their fullness.

Laennec was familiar with both methods—in fact, one of his teachers (and Napoleon’s personal physician), Jean-Nicolas Corvisant, had helped popularize the percussion technique—but neither would do him any good with this patient. The young lady was on the heavier side and ample in the chest, which presented some complications.

“Percussion and the application of the hand were of little avail,” Laennec wrote of the exam, “on account of the great degree of fatness.” Putting his ear right up to her chest was also “rendered inadmissible” by the Catholic bachelor’s social unease at putting his head that close to a young woman’s bosom. He later said of examining female patients that, “direct auscultation was as uncomfortable for the doctor as it was for the patient…It was hardly suitable where most women were concerned and, with some, the very size of their breasts was a physical obstacle to the employment of this method.”

After a few embarrassing minutes, Laennec remembered “a simple and well known fact in acoustics…the augmented impression of sound when conveyed through certain solid bodies—as when we hear the scratch of a pin at one end of a piece of wood, on applying our ear to the other.”

He grabbed a sheet of paper, rolled it up and placed one end against the woman’s chest and the other against his ear. He was “surprised and elated to be able to hear the beating of her heart,” he wrote, “with far greater clearness than I ever had with direct application of my ear.”

Over the next few years, Laennec experimented with his improvised tool and perfected its design. A wooden tube carried sound better than paper, and pine seemed to work especially well. He struggled with a name for his invention, though, and toyed with pectrolique, medical cornet and thoraciscope before settling on stethoscope, from the Greek stethos (“chest”) + -scope (“look or examine”).

Satisfied with his design, Laennec went on to use the stethoscope to catalog and describe various sounds of the chest and correlate them to specific ailments. After three years, he published the landmark De l’Auscultation Médiate, ou Traité du Diagnostic des Maladies des Poumons et du Coeur (or, On Mediate Auscultation, or Treaty of Diagnosing Diseases of the Lungs and the Heart).

Besides having an advanced instrument for it, it seems only natural that Laennec would be drawn to treating diseases of the chest: his mother, the uncle that helped raise him, and a few of his mentors all died of tuberculosis. Laennec himself would eventually contract the disease and die from it in 1826. He left his personal stethoscope to his nephew.

Laennec’s invention received its fair share of criticism at first. Even John Forbes, the Scottish physician who translated De l’Auscultation Médiate into English, said that, “It must be confessed that there is something even ludicrous in a grave physician formally listening through a long tube applied to the patient's thorax, as if the disease within were a living being that could communicate its condition to the sense without.” Eventually, though, it gained wide acceptance. With modifications by others, like Arthur Leared and Nicholas Comins’ binaural versions, the stethoscope became an indispensable tool by the 20th century.

How much longer the stethoscope stays that way is uncertain, though. Dr. Bryan Vartabedian, MD, on his blog 33 charts, looked at a 1993 study done by researchers at the Medical College of Pennsylvania. They found, in a nationwide survey of medical training program directors and students, that only 27.1 percent of internal medicine and 37.1 percent of cardiology programs offered structured teaching of chest auscultation, and that accuracy with a stethoscope ranged from 0 percent to 56.2 percent for cardiology fellows, and from 2 percent to 36.8 percent for medical residents.

At the end of that decade, the lead author on that study conducted a similar survey, and found an uptick in the internal medicine programs teaching chest auscultation (up to 48 percent for cardiac auscultation). He didn’t check in on internal med programs again, but only 29.2 percent of family practice programs taught cardiac auscultation and 12.2 percent taught pulmonary auscultation.

This piece was originally published in 2013.