Stethoscope
A stethoscope is an acoustic medical instrument, used for the Auscultation, i.e. the listening of the internal sounds to the human body.
History
The stethoscope was invented in 1816 in France, by the doctor Rene Laennec. It was not whereas about a simple rolled paper bundle, making it possible to move away the ear from the Médecin of his patient for reasons of decency. It created the mediate sounding thus in opposition to the immediate sounding where it had the head stuck to the chest of the patient. Its first written description of its system goes back to March 8th 1817. Laennec built several models out of wooden secondarily of them.The model was improved by it towards 1830 by Pierre Piorry which built an ivory adapter on the auricular side. About the same time, a flexible tube connects the house to the ear-phone but the rigid model still will persist a few decades.
The binaural stethoscope (for the two ears) was imagined as of 1829 but was built only in 1851. The tube was in rubber but this solution proved to be fragile and had to be abandoned. A second model, more rigid, saw the day in 1852 containing metal tubes.
Towards 1870, differential stethoscopes appear: two houses, assembled each one on a tube and connected to an ear, were to make it possible to compare the sounding with two different places.
In 1961, Dr. David Littmann created the contemporary stethoscope with its double reversible house, which remains always nowadays used.
The contemporary stethoscope
Currently, the stethoscopes comprise one or two houses, metal parts equipped with a membrane which one applies to the skin of the patient. This membrane, put in vibration by the body sounds, is connected by one or two flexible tubes to the ends that the operator (doctors and kinesitherapists mainly) place in his ears. The rigidity of the system at the auricular level, is done thanks to a metal reinforcement: the quadrant. By its construction, it constitutes an acoustic amplifier (broad house, small ear-phones). The sensors can filter certain frequencies, to collect the sounds more specifically acute or serious, according to the diagnoses to be carried out. Models with electronic amplification were built, without real business success.One generally makes use of it to listen to the cardiac beats, breathing, but one also listens to the Intestin S and the blood Circulation (primarily arterial), as well as the fetal noises.
External bonds
Illustrated history of the stethoscope
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