Jean Nicolas Corvisart (1755-1821) revolutionized a technique called percussion. This was a technique whereby the physician would tap on the chests and diagnose conditions based on the sounds emitted. Prior to the invention of the stethoscope this was the only means available to assess the lungs, other than placing your ear upon the chest of your patient.
Prior to the 19th century diagnosis of lung disease was made by patient complaint and physician assessment without any tools. By the 1850s physicians had access to to the technique of chest percussion and a tool that was aptly named the stethoscope.
A famous student of Corvisarts was Rene Laennec (1781-1826). He learned the practice of percussion from Corvisart. In 1815 Lenaec discovered almost by accident that sounds of the heart and lungs were amplified when a hollow cylinder of wood was placed on the chest and listened to by the ear. In other words, Laennec had invented the stethoscope. (1)
The Catholic Encyclopedia notes that Corvisant may have been the first to describe the technique of vocal fremitis, which is where a hand is placed over the chest and noting the vibrations -- fremitis -- felt when the person speaks. Like percussion, vocal fremitis is a technique still used by physicians today. (2)
Erik Soiferman and Eric Rackow write how Corvisart wanted a book written on the subject, and Laennec did just that when he published "A Treatise on Diseases of the Chest, and of Mediate Auscultation" in 1819. Yes, like percussion, the stethoscope was likewise initially rejected by the medical community. (3)
Like Corvisart, Laennec would use percussion and his newly invented stethoscope and make an educated guess as to what the patient's condition was. Then he would perform autopsies to confirm what he found. By the time of Laennec's death in 1826 both percussion and auscultation were common practice in the field of medicine as techniques to aid the physician in diagnosing.
Pierre Adolph Piorry was born in 1794, served in the Napoleanic wars in Spain, and, like Laennec, served as a student of Corvisart, according to A. Sakula in his article, "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry" in the October, 1979 issue of Thorax. (4)
Sakula explains that Piorry qualified as a physician in 1816, the same year Laennec invented the stethoscope. Laennec went on to make several adjustments to the stethoscope, and by the time he had it perfected to his liking it was about a foot long.
One difference between his stethoscope and what we use today is his was about a foot long and it was monaural, which meant that only one ear was used instead of both. One hollowed tube was used and it was set on the chest of the patient, while the other end was set against the doctor's ear.
Piorry further adjusted the stethoscope design and perfected to a point that it was his design that was used for the remainder of the 19th century. Antiquemed.com, "Binaural Stethescope," describes his stethoscope as trumpet shaped, made of wood, was shorter, and thinner than Laennec's. It came with removable wood plug, ivory earpiece and chest piece, with the chest piece also serving as a pleximeter. This design was also much more pleasing to physicians, and was much easier to carry in their bags. (5)
Sakula described how Piorry wished to be a famous physician like Laennec. Piorry even wrote a poem about how he prayed to discover something that would make him famous. Then one day "a few months later," Sakula wrote, "he had slight pruritus and while scratching the skin over his chest he heard a sound. He interposed a coin and scraped it and obtained a stronger sound, which varied according to the density and elasticity of the underlying organ."
The next day he began his work on percussion, and hoped to accomplish for percussion what Laennec had accomplished for auscultation. In 1826 he wrote a paper that described his new technique of doing percussion, which involved placing a small plate between the patient's skin and the percussing finger. He called the plate a pleximeter from the Greek words to strike and to measure.
Sakula also explained that Piorry did not see his methods of percussion as competing with auscultation, he believed they should be used together to gain a more thorough picture and help with properly diagnosing the patient. Today many physicians use a combination of this technique, which is to use the finger of one hand as the pleximeter and the finger of the other hand as the percussor. Yet the principle is still the same.
Piorry remained a famous physician until his retirement at the age of 72 in 1866. He died at age 85 in 1879, yet many of his contributions to the medical field, especially that of percussion, are still used to this day. Piorry's addition to the percussion technique lives on to this day pretty much as he left it. Yet the stethoscope has been recreated many times by many different designers. Most stethoscopes used in the 19th century after Piorry's death were based on his design.
Meanwhile, by 1854 percussion had been fine tuned so that it was often performed over various organs to help the doctor determine if there were any pathological disorders. Calvin Newton, in his book "Thoracic diseases: their pathology, diagnosis and treatment," (Massachusettes, page 91), describes that there are two sounds to listen for: dulll or resonant. (6)
Newton writes that the resonant sound is heard under percussion of a space or empty space, such as if there were extra air in the chest cavity as is the case with emphysema or during an asthma exacerbation, or over the side of a chest where the lung had been removed. The dull sound would be heard over a solid, as if fluid or a tumor were filling part of the lung. The heart itself is a solid object that produces a dull thud upon percussion.
Another example Newton gives is the resonant sound would be heard when percussing an empty barrel or cask, and the dull sound heard when percussing a cask or barrel filled with fluid. By memorizing the different sounds heard over various parts of the body, a physician can determine if there have been any changes to underlying structures, such as the heart, lung, kidneys, etc.
Percussion in this manner is still used by physicians to this day, although it is used as one tool to aide the physician in diagnosing and monitoring the progression of a patient over time.
Stanley Joel Reisner, in his 1979 article "The Medical Influence of the Stethescope" in Scientific America, describes a stethoscope designed by Nicholas Comins in 1929 that was the first that wasn't completely rigid, although it still used to rigic wood tubes about 7 inches long each that were "connected by a joint so they could be set at any angle; an earpiece attached to one of the tubes also rotated about a joint." (7)
Reisner describes Comin's monoural stethescopes as being two feet long so the doctor didn't have to get so close to the patient, and the patient didn't have to keep moving to new positions so the doctor could listen to different areas of the chest. This greater distance, Reisner notes, was also good for patients with contagious diseases as the doctor could keep his distance.
Likewise in 1929 Comins designed the first binaural stethoscope, or one that would allow the use of both ears to listen to lung and heart sounds. Yet Comin's design for a binaural stethoscope never got off the shelves and, Reisner writes, it wasn't until the 1850s that any "satisfactory" binaural stethescope was on the market.
Charles Williams, the man who proved bronchospasm in 1840, devised a binaural stethoscope that used two bend pieces of pipe. Yet his stethoscope was hardly feasible. OhioHistoryCentral.org describes Dr. Nathan B. Marsh as receiving the first patent for a binaural stethoscope in 1851 in Cincinnati Ohio. His was feasible because the tubes were made of rubber. (8)
However his stethoscope was fragile and never gained acceptance by the market. The first practical binaural stethoscopes was designed by George P. Camman in 1855 in New York Antiquemed.com explains Camman didn't take credit for the invention of the binaural stethoscopes. Instead he claimed to have used previous designs and incorporate them into a more ideal stethoscope. You can see a picture of it here. (9)
Antiquemed.org describes Camman's stethoscope this way: "Cammann's model was made with ivory earpieces connected to metal tube that were held together by a simple hinge joint, and tension was applied by way of an elastic band. Attached to these were two tubes covered by wound silk. These converged into a hollow ball designed to amplify the sound, and attached to the ball was a conical shaped, bell chest piece"
Tension on the earpieces held them in the physicians ear so he could listen without holding them in, and he could focus on where he was placing the bell on the patient's chest instead.
Kind of like when Ben Franklin invented the lightning rod, Marsh never asked for a patent because he believed such a device should be readily available for the public good. While the modern day stethoscope has changed quite a bit since Marsh's stethoscope, most still utilize his basic design.
Still, like most medical inventions, the binaural stethoscope was not immediately accepted by the medical community. As antiquemed.com describes, it wasn't until 1866 when Dr. Austin Flint endorsed the binaural stethoscope that it gained acceptance. Dr. Austin had previously spoken negative about it.
As the binaural stethoscope was improved upon, it slowly gained greater acceptance in the medical community, and by the turn of the 19th century it was the main type of stethoscope used by doctors. Today one couldn't imagine a doctor, nurse or RT without one looped around his or her neck.
Obviously there are many brands of stethoscopes available at a variety of prices, yet the most accepted by the medical community is the Littman Stethoscope. According to 3M, the makers of the Littman, Joseph Littman was a cardiologist who came up with a design that greatly improved the "acoustics performance" of the stethoscope. He wrote about this improved design in the American Journal of the American Medical Association. (10)
It was the first stethoscope with a single lumen bore and the chest piece was designed to hear a variety of different pitches of sound. The stethoscope is light, easy to carry, and I personally love mine.
To view pictures of the Piorry Stethoscope click here. To read a more thorough history and view pictures stethoscopes through the ages you can click this link to antiquemed.com. Check out any of the links below or above for further reading.
- Williams, Henry Smith, "The Century's Progress in Scientific Medicine," Harper's Magazine, 1899, page 38
- "The Catholic Encyclopedia, "Leopold Auenbrugger," http://www.newadvent.org/cathen/02072a.htm
- Soifermann, and Eric Rackow, "A Treatise on Diseases of the Chest, and of Mediate Auscultation," 1819.
- Sakula, A., "Pierre Adolphe Piorry (1794-1879): pioneer of percussion and pleximetry," October, 1979, Thorax ( 34(5): 575–581).
- "The Binaural Stethoscope," antiquemed.com, http://www.antiquemed.com/binaural_stethoscope.htm, information reviewed March 8, 2012
- Newton, Calvin, "Thoracic diseases: their pathology, diagnosis and treatment," 1854, Massachusettes, page 91
- Reisner, Stanley Joel, "The Medical Influence of the Stethescope," Scientific America, 1979, February, vol. 240, number 2, page 148-156
- "Stethoscope," OhioHistoryCentral.org, http://www.ohiohistorycentral.org/entry.php?rec=2734, site viewed March 8, 2012
- "The Binaural Stethoscope," Antiquemed.com, http://www.antiquemed.com/binaural_stethoscope.htm, site viewd March 8, 2012, great history of the stethoscope with impressive pictures
- "History: Evolution of an essential tool: Modern Stethoscopes: Nearly 200 years in the making," 3M.com, http://solutions.3m.com/wps/portal/3M/en_US/3M-Littmann/stethoscope/littmann-learning-institute/about-stethoscopes/stethoscope-history/, site viewed March 8, 2012