Kids helped inspire stethoscope’s invention


Lots of professionals can be identified by the tools they use. Plumbers have wrenches. Carpenters have hammers. Doctors have stethoscopes. I don’t know anything about the origin of wrenches or hammers, but the stethoscope has an interesting history.

Stethoscopes transmit sounds in a way that makes them easier to hear. Doctors use stethoscopes to hear sounds made by the body. If you place a stethoscope on a person’s chest, you can hear his heartbeat. If you place it on a person’s back, you can hear him breathe. If you place it on the belly, you can hear rumbling and tinkling sounds made by the intestines. Stethoscopes are also used with special cuffs to measure a person’s blood pressure.

(bigstock) - Early stethoscopes were made of wood.

A gaucho rides a wild horse during the annual celebration of Criolla Week in Montevideo, April 15, 2014. Throughout Easter Week, 'gauchos', the Latin American equivalent of the North American cowboy, from all over Uruguay and neighboring Argentina and Brazil will visit Montevideo to participate in the Criolla Week to win the best rider award. The competition is held from April 13 to April 20 this year. REUTERS/Andres Stapff (URUGUAY - Tags: ANIMALS SOCIETY)

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The loudest sound made by the intestines is called borborygmus (pronounced bor-bo-RIG-mus). It comes from the movement of gas and fluid within the intestines and is so loud, you can often hear it without a stethoscope!

Doctors knew about bodily sounds before the stethoscope was invented, but in order to hear them, the doctor had to place his ear on the body part he wanted to listen to. Can you imagine how it would feel if a doctor with hairy ears put his head on your chest to listen to your heart?

Of course, from the doctor’s perspective, I’m sure it wasn’t too pleasant to put his ear on a sweaty teenager who hadn’t bathed in weeks. To get around that, doctors sometimes placed a small cloth on the patient’s body before bending down for a listen.

The stethoscope was invented in 1816 by a French doctor named René Laennec (leh-NEC). The story goes that Laennec was asked to see a woman with heart disease. On his way to visit the patient, Laennec noticed a group of children playing on a pile of lumber. One of them scratched the end of a wooden beam with a pin while the other listened to the sound at the other end. Laennec realized the sound had been transmitted from one end of the wood to the other.

When Laennec arrived at the patient’s home, instead of using his regular technique, he rolled a piece of paper into a cylinder and placed it on the woman’s chest. Details about the story vary, but Laennec later wrote that the sounds he heard were clearer than anything he had previously noted by placing his ear against a patient’s chest.

Laennec spent the next three years experimenting with various designs and types of wood to perfect his stethoscope. The first stethoscopes were made of wood and were monaural in design. That means the doctor used only one ear to listen to his patients. Stethoscopes made with flexible tubes and binaural earpieces (one for each ear) began to appear in the 1850s.

In addition to inventing the stethoscope, Laennec used it to learn what sounds were present in lung conditions such as pneumonia and emphysema. Although antibiotics to treat those conditions wouldn’t be discovered until 100 years later, Laennec’s invention revolutionized the way medicine was practiced.

— Howard J. Bennett

Bennett is a Washington pediatrician. His Web site,, includes past KidsPost articles and other cool stuff.

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