THE HISTORY OF THE STETHOSCOPE

THE HISTORY OF THE STETHOSCOPE 

The stethoscope was invented in France in 1816                                                                  by René Laennec at the Necker-Enfants Malades Hospital in Paris.    

     Photo courtesy of the US National Library of Medicine

It consisted of a wooden tube and was monaural.

     

The word stethoscope is derived from the two Greek words, stethos (chest) and scopos (examination). Apart from listening to the heart and chest sounds, it is also used to hear bowel sounds and blood flow noises in arteries and veins.

Since mankind first began to study human physiology, and the physical characteristics associated with various ailments, it has been obvious that the heart plays a crucial role in our bodies. The sounds it makes, as well as the sounds that the surrounding organs, such as the lungs, make can be crucial indicators when examining a patient. The act of listening to these sounds, known as auscultation, has been refined using even more powerful tools to aid physicians in this crucial examination.

In the early 1800’s, and prior to the development of the stethoscope, physicians would often perform physical examinations using techniques such as percussion and immediate auscultation. In immediate auscultation, physicians placed their ear directly on the patient to observe internal sounds. 

   Drawings of the early stethoscope by Rene Theophile Hyacinthe Laënnec, 1819.

This technique suffered from several drawbacks, the foremost being that it required physical contact between the physician and the patient and proper placement of the ear. In addition, the sounds observed by the physician were not amplified in any way, creating the possibility of missing key sounds that might indicate potential illness. Finally, the act of performing immediate auscultation could be awkward for both the physician and patient.

To resolve the limitations of immediate auscultation, a French doctor named Rene Theophile Hyacinthe Laënnec (1781–1826) at the Necker-Enfants Malades Hospital in Paris invented the first stethoscope in 1816. During an examination of a patient, he was afforded few diagnostic clues from application of a hand to the chest or the commonly used percussion method. Reluctant to perform immediate auscultation on the young female patient, he used a rolled sheet of paper to create an aural tube and facilitate auscultation. He was excited to discover that the heart sounds were clearly audible, and this discovery later lead to the development of the first device specifically for this purpose. (3) The first stethoscope consisted of a wooden tube and was monaural. Similar to a hearing aid known as an ear trumpet, it allowed the physician to more comfortably perform auscultation. 

Rene Theophile Hyacinthe Laënnec examines a patient in front of his students at Necker Hospital in this painting by Theobald Chartran.

It would not be until 1851 when the stethoscope had its next major improvement, which was to make the device bi-aural. Invented by Irish physician Arthur Leared, it was refined in 1852 by George Cammann for commercialization. Cammann also wrote a major treatise on diagnosis by auscultation, which the refined binaural stethoscope made possible. (4) Initially there was some concern that the bi-aural stethoscope could create hearing imbalances which might be problematic during examinations, but by the early 1900’s these concerns had largely subsided and the bi-aural stethoscope was a commonly used diagnostic instrument.

Throughout the 20th century many minor improvements were made to these iconic devices to reduce weight, improve acoustic quality, and filter out external noise to aid in the process of auscultation. Electronic versions of the stethoscope were introduced to further amplify sound. Stethoscopes are now available in a wide array of styles, with designs available for virtually every branch of medicine.

Despite all of the improvements and changes, the basic principle behind the stethoscope continues to remain the same; to provide physicians with the means to perform auscultation and identify specific sounds within the body.

References

• 1. (n.d.) South Australian Medical Heritage Society Inc, Website for the Virtual Museum Retrieved from http://samhs.org.au/Virtual%20Museum/Medicine/stethoscopes/stethoscopes.html
• 2. (n.d.) The Rose Melnick Medical Museum. A short history of stethoscopes. Retrieved from http://rosemelnickmuseum.wordpress.com/2009/12/01/a-short-history-of-stethoscopes/
• 3. Ariel Roguin, MD, PhD. (Clin Med Res. 2006 September; 4(3): 230–235.). Rene Theophile Hyacinthe Laënnec (1781–1826): The Man Behind the Stethoscope. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1570491/
• 4. Stethoscope. (4 January 2013 at 02:16). Retrieved from Wikipedia: http://en.wikipedia.org/wiki/Stethoscope#cite_note-1

The above story is from:

http://adctoday.com/learning-center/about-stethoscopes/history-stethoscope

The Melnick Medical Museum –                                Youngstown State University

http://melnick.ysu.edu/

The Rose Melnick Medical Museum was founded in 1985                                                         by Dr. John C. Melnick, radiologist in Youngstown, Ohio.

A short history of stethoscopes

Today stethoscopes are a typical fixture around doctors’ necks. They are commonly used to listen to the sounds of the heart and lungs as well as the flow of blood during blood pressure readings.

The practice of percussion and immediate auscultation were popular in physical examinations by the early 1800s. In immediate auscultation, physicians placed their ear directly on the patient to observe internal sounds. A French physician named Rene Laennec (1781-1826) was a firm believer in this method of diagnosis. He worked to refine the auscultation procedure and link the sounds with specific physiological changes in the chest.

Immediate auscultation could be an awkward procedure, particularly for female patients.  In 1816, Laennec found himself in one of these situations. He rolled a few sheets of thick paper into a tube shape and applied the tube to the woman’s chest instead of his ear. Later, he made a more durable instrument out of wood and called it the stethoscope. It was a monaural model that consisted of one tube and was used on one ear.

                                 monaural stethoscope, c1890

The first practical bi-aural stethoscope was made in 1851. Flexible tubing is required to make a stethoscope that allowed physicians to use both ears. While many physicians readily adopted monaural stethoscopes, the bi-aural stethoscopes were met with some skepticism. Doctors worried about hearing imbalances caused by using both ears instead of one. For this reason, many doctors continued to use monaural stethoscopes into the early 1900s.

                                              Camman’s model, c1900

The stethoscopes used today are very similar to the ones used in the 1930s. New materials such as flexible rubber, stainless steel, and tygon make them lighter and easier to use. The bells (the end of the instrument applied to patient’s body) have also become flatter. The application of electronic amplifiers to the stethoscope provided the next major modification. These stethoscopes amplified the sound heard by the physician and were capable of filtering high pitched tones in order to make faint tones louder. Some electronic models could provide visual or audio recordings that could be used in training or consultation as well.

 

              Maico Stethetron, c1948

The stethoscope is one of the medical instruments whose development has been dependent on the invention of new materials such as rubber and stainless steel. The sounds the stethoscope produces has been aided by the better understanding of the relationship between anatomy and the laws of physics. Not only did doctors need to understand how to efficiently transmit sound through tubes, they also need to understand how sound waves reacted in the various tissues of the body. These are some of the issues explored in our upcoming exhibit “Tools of the Trade: The history of medical instrumentation.”