The stethoscope is the most recognisable of all pieces of medical equipment, and is identifiable by even the smallest children as being representative of a doctor. Its inventor René Théophile Hyacinthe Laënnec would have turned 235 on February 17, and has been honoured with a Google Doodle.
Fear of Boobs Useful to Humanity – Invention of Stethescope
How fear of women’s chests led a doctor to invent the stethoscope
Who was René Laënnec?
Laennec was born in 1781 in France, and studied medicine under his physician uncle in Nantes until he was called to serve as a medical cadet in the French Revolution.
He was revered as an excellent student after he resumed his studies in Paris in 1801, and began working in the Necker Hospital once the French monarchy had been reestablished in 1815.
When did Laënnec invent the stethoscope?
In 1816, shyness led Laennec to invent the stethoscope. He was examining a young woman complaining of heart problems. At that time, doctors generally listened to patients’ heartbeats by resting an ear against the patient’s chest, but the conservative Laennec thought this improper under the circumstances, especially as she was overweight. He rolled a piece of paper into a tube and pressed it to her chest, allowing him to hear the sounds of her heart. Some believe he was inspired by the flute, which he used to play.
“I happened to recollect a simple and well-known fact in acoustics, … the great distinctness with which we hear the scratch of a pin at one end of a piece of wood on applying our ear to the other,” he wrote in the preface to his seminal research paper De l’Auscultation Médiate in 1819. “Immediately, on this suggestion, I rolled a quire of paper into a kind of cylinder and applied one end of it to the region of the heart and the other to my ear, and was not a little surprised and pleased to find that I could thereby perceive the action of the heart in a manner much more clear and distinct than I had ever been able to do by the immediate application of my ear.”
Inspired by his paper experiment, he built several hollow wooden prototype instruments attached to a single microphone at one end and earpiece at the other, and named it the stethoscope. The term is derived from the Greek words ‘stethos’ for chest, and ‘scopos’ for examination.
The evolution of the stethoscope
The instrument was swiftly adopted across France and wider Europe, before spreading to the US. Laennec died of tuberculosis aged just 45 in 1826, but was aware of the importance of his discovery, calling it “the greatest legacy of my life”.
In 1851 Irish physician Arthur Leared invented a binaural stethoscope, which fitted into both ears, made of a durable plastic called gutta-percha. The first commercially available instrument, made of India rubber and wood, was patented the same year by Doctor Nathan Marsh of Cincinnati. Unfortunately it was too fragile to be used properly.
The next year New York-based doctor George Cammann successfully adapted the design for wider commercial production, made of ivory earpieces connected to a metal tube held together by a hinge. Known as Cammann’s Stethoscope, variations of the design have remained in use ever since.
Cammann never patented his design because he believed it should be freely available to all .
How to use a stethoscope
Is the stethoscope becoming obsolete?
Electronic stethoscopes that amplify the sounds in the chest and produce graphs were developed in the 1970s.
Now, doctors agree that a minimum of 10 minutes is required to fully examine a patient using a stethoscope, and that radiographs are required to identify the majority of underlying chest problems. Robert L Wilkins, from the department of Cardiopulmonary Sciences at Loma Linda University, California, has branded the procedure “very inefficient“.
Handheld ultrasonic devices can now diagnose various conditions, and concerns have also been raised over how hygienic the instruments are. Medical journal The Lancet detailed how researchers had collected 100 stethoscopes from various departments in a London teaching hospital and found bugs on all of them, with 21 carrying staphylococci, one of the bacteria that cause food poisoning. However, wiping the bell and diaphragm of the instrument with disinfectant after use on each patient practically eliminates this risk.
Recently stethoscopes are becoming increasingly digitised – last year, a new stethoscope transmitted sounds from the heart and lungs to a smartphone app and directly to a digital database.