The Stethoscope

Figure 1. One of the earliest cylindrical stethoscopes

Brief: The stethoscope was invented in 1816 by a young doctor by the name of Rene Theophile Hyacinthe Laennec. Previously, the only way to listen to a patient's heartbeat and breathing was to place the ear to the chest (Immediate Auscultation). However, being embarrassed by doing so to a young female patient, Laennec used some quick thinking and rolled up 24 sheets of paper into a cylinder. By placing one end on the patient's chest and the other to his ear, he noted that the sound was not only louder, but clearer as well. At first Laennec was hesitant to name the device as he thought that something so intuitive would not require a name, but he eventually came up with one because he disliked the ones his colleagues gave and thus the Stethoscope was coined.

Figure 2. Bi-aural type Stethoscope

The earliest stethoscopes consisted of a wooden cylinder that had an opening that widened at one end, similar to an enclosed ear trumpet. These models of stethoscopes were named Laennec stethoscopes after the man who invented them. It wasn't until 1851 that the stethoscope would receive its next improvement. George Cammann began commercialization for the bi-aural (two eared) stethoscope. Modern stethoscopes are minor improvements on the bi-aural design with adjustments to sound quality, weight reduction and noise filtering.

Figure 3. Modern Stethoscope

Use: The operation of a stethoscope is simple, by placing both earbuds in the respective ears of the operator, the operator is then free to move the diaphragm wherever they desire, this allows them the freedom to examine multiple locations on the patient and check for auditory signs of illness with relative ease.

Additional Information: Reference 1, Reference 2, Reference 3