Stethoscope is currently one of the most widely used tools that doctors and nurses use for diagnostic purposes. These stethoscopes have two ear pieces and a bell-like end that is placed on the body. Stethoscopes are not only used to listen to the chest, but also other parts of the body, such as the bowels and during pregnancy. Before the 1800s, however, doctors would place their ear directly onto the patient’s chest, a practice called auscultation. 

This all changed when French doctor, René Laennec, invented the stethoscope in 1816 —although unlike the stethoscope familiar to patients today — the original device was a simple tube.

While consulting a female patient, Laennec needed to listen to the woman’s chest. As the patient was somewhat overweight, Laennec thought it both improper and inadequate to place his head on her chest and listen directly. He rolled up a sheet of paper into a tube and placed one end on the patient’s chest. The tube magnified sound, and Laennec found he could hear her lung sounds easily by putting his ear to the open end. The rolled up piece of paper was soon replaced by a hollow wooden tube. Laennec named his invention the ‘stethoscope’.

In 1828 Pierre Adolphe Piorry included the concept of the diaphragm, whereby an ivory chest piece acted as a pleximeter. The shapes of the bell and chest piece were changed, as well as the materials used to construct the instrument. 

By the 1850s, the stethoscope had become one of the doctor’s vital tools. Learning to listen and diagnose the sounds from the chest became an important part of a doctor’s training. This is according to sciencemuseum.org

The next important development, according to hekint.org, was the binaural stethoscope. This was invented by Irish doctor Arthur Leared in 1851. George Phillip Camman further refined it in 1853 and wrote a paper on diagnosis by auscultation, now much improved with the novel binaural stethoscope. As with any new invention there was at first much skepticism—would there not be hearing imbalance due to using both ears to listen? But these fears proved unfounded, and the use of the new binaural stethoscope became widespread.

Electronic stethoscopes that amplify the sounds in the chest and produce graphs were later produced in the 1970s and continue to be refined. Many developments and modifications were made as the use of the stethoscope became more popular. 

The next development, by Dr Robert Bowles in 1894, was combining the diaphragm with the bell. This "combination” stethoscope remains the basis of those still used today. Today, a stethoscope around the neck is one of the most popular images of the medical profession.