The Strange Story Behind the Invention of the Stethoscope

One of the first images our brain conjures up when we think about doctors is the acoustic medical device called the stethoscope. It’s extremely hard to miss against the backdrop of a doctor’s white medical lab coat and due to it’s funny looking design, we are almost always immediately drawn to it. The stethoscope is generally made up of three components, the small disc-shaped resonator, the long black tube that splits in two, and the earpieces. It is derived from two Greek words meaning chest (stethos) and examination (scopos) and is used to listen to your heart, chest, bowel, and blood flow sounds. Of course, the design that we know now to be the stethoscope has had a few minor upgrades, design changes, and material modifications along the way. The origin of the stethoscope and its creator, Rene Theophile Hyacinthe Laennec, is a little bit curious and strange but quite a necessary advancement for the medical field.

The Techniques Of Medical Percussion and Auscultation

Prior to the development and invention of the stethoscope, physicians during the 19th century were systematically exploring the clinical meanings behind heart and breath sounds by gathering data during patient examinations. During these physical examinations, physicians would use a technique called percussion and auscultation, where the physician would strike the chest using one’s fingertips and then immediately place one’s ear against the chest to listen. Unfortunately, not only did these methods come with limitations like the inability to amplify the sounds but it required awkward, physical contact with the patient and precise ear placement. Although Rene Laennec was quite adept at percussion and auscultation, his demand for diagnostic precision,  his critical views of obese patients, and his inability to be on time for appointments is what led to the invention of the stethoscope.

How The Idea for the Stethoscope Was Cultivated

During the Autumn months of 1816, Laennec was scheduled to examine a young woman who had been laboring with heart disease symptoms. Unfortunately, Laennec was running late that day and so he took a shortcut through a courtyard at the Louvre and saw a group of children playing. According to PBS, the children were playing with a narrow wooden beam which one child held up to their ear while another tapped nails against it to transmit the sound through the beam. Although we are unsure of whether this event directly contributed to his invention, Laennec did mention that his invention was inspired by the science of acoustics and in particular how sound is conveyed through solid bodies.

When Laennec finally reached his patient, rather than using the percussion and auscultation techniques to listen to her chest, he asked for a piece of paper. He rolled it up into a cylinder, placed it against the patient’s chest, and was amazed at how well he could hear the action of the heart. According to Laennec, the heart sounds were much more clear and distinct than he had ever been able to hear with the application of his ear to the chest. Upon being amazed at what he could hear, Laennec began experimenting with a series of hollow tubes made out of cedar and ebony wood. Between the years of 1816 and 1819, Laennec would experiment continuously until he arrived at a model that was about one foot in length and 1.5 inches in diameter with a 1/4-inch central channel.

The invention of the stethoscope allowed Rene Laennec to become the first physician to reliably distinguish between lung abscesses, bronchiectasis, emphysema, hemorrhagic pleurisy, pneumothorax, and pulmonary infarcts. He was also able to describe their associated heart sounds and murmurs, widening the understanding between these cardiac maladies. Although the stethoscope went through some major changes to weight, acoustic quality, and design, the basic principle has remained the same since its inception and is now a widely accepted and essential diagnostic tool.