Editing Stethoscope (section)

==History==
{{Anchor|history}}

[[File:Laennecs stethoscope, c 1820. (9660576833).jpg|thumb|This early stethoscope belonged to Laennec. ([[Science Museum, London]])]]

[[Image:Hörrohr Stethoskop Meyers 1890.jpg|thumb|right|Early stethoscopes]]

[[File:Toraube2.jpg|thumb|180px|right|A [[Ludwig Traube (physician)|Traube]]-type stethoscope in ivory]]

The stethoscope was invented in [[France]] in 1816 by [[René Laennec]] at the [[Necker-Enfants Malades Hospital]] in [[Paris]].<ref name="Wade2008">{{cite journal|last1=Wade|first1=Nicholas J.|last2=Deutsch|first2=Diana|title=Binaural Hearing – Before and After the Stethophone|journal=Acoustics Today|date=July 2008|volume=4|issue=3|pages=16–27|doi=10.1121/1.2994724|url=http://acousticstoday.org/wp-content/uploads/2017/07/Article_2of3_from_ATCODK_4_3.pdf}}</ref><ref>{{cite book |last=Laennec |first=René |title=De l'auscultation médiate ou traité du diagnostic des maladies des poumon et du coeur |location=Paris |publisher=Brosson & Chaudé |year= 1819 |url=https://books.google.com/books?id=TtTTeKls2bUC&pg=PR5 }}</ref><ref name="Laennec_Forbes_translation">'Laennec, R. T. H.;  Forbes, John, Sir, ''[https://books.google.com/books?id=a1pBAQAAIAAJ&pg=PR1 A Treatise on the Diseases of the Chest and on Mediate Auscultation]'' (1835). New York : Samuel Wood & Sons; Philadelphia : Desilver, Thomas & Co. .</ref> It consisted of a wooden tube and was [[monaural]]. Laennec invented the stethoscope because he was not comfortable placing his ear directly onto a woman's chest in order to listen to her heart.<ref>{{cite journal|title=Rene Theophile Hyacinthe Laënnec (1781–1826): The Man Behind the Stethoscope|author=Roguin A|date=September 2006|pmc=1570491|pmid=17048358|volume=4|issue=3|pages=230–5|journal=Clin Med Res|doi=10.3121/cmr.4.3.230}}</ref><ref name="picard-victorian-london">{{cite book|last1=Picard|first1=Liza|author-link1=Liza Picard|title=Victorian London: the life of a city, 1840–1870|date=2005|publisher=Weidenfeld & Nicolson|location=London|isbn=978-0297847335|language=En}}</ref>{{rp|186}} He observed that a rolled piece of paper, placed between the individual's chest and his ear, could amplify heart sounds without requiring physical contact.<ref>{{Cite book|title=Mending Bodies, Saving Souls|last=Risse|first=Guenter|publisher=Oxford University Press|year=1999|isbn=978-0-19-505523-8|location=Oxford|pages=316}}</ref> Laennec's device was similar to the common [[ear trumpet]], a historical form of hearing aid; indeed, his invention was almost indistinguishable in structure and function from the trumpet, which was commonly called a "microphone". Laennec called his device the "stethoscope"<ref name="Foreign_Medicine_and_Surgery_1820">{{Citation |year=1820 |title=Laennec's new system of diagnosis |journal=The Quarterly Journal of Foreign Medicine and Surgery and of the Sciences Connected with Them |volume=2 |pages=51–68 |url=https://books.google.com/books?id=LNVLAAAAYAAJ&q=stethoscope&pg=PA58 |postscript=.}}</ref> (''[[wikt:stetho-#Prefix|stetho-]]'' + ''[[wikt:-scope#Suffix|-scope]]'', "chest scope"), and he called its use "[[wikt:mediate#Adjective|mediate]] auscultation", because it was [[auscultation]] with a tool intermediate between the individual's body and the physician's ear. (Today the word ''auscultation'' denotes all such listening, mediate or not.) The first flexible stethoscope of any sort may have been a binaural instrument with articulated joints not very clearly described in 1829.<ref>Wilks, p. 490, cites Comins, "A flexible stethoscope", ''Lancet'' 29 August 1829.</ref> In 1840, [[Golding Bird]] described a stethoscope he had been using with a flexible tube. Bird was the first to publish a description of such a stethoscope, but he noted in his paper the prior existence of an earlier design (which he thought was of little utility) which he described as the snake ear trumpet. Bird's stethoscope had a single earpiece.<ref>Samuel Wilks, "Evolution of the stethoscope", ''Popular Science'', '''vol. 22''', no. 28, pp. 488–91, Feb 1883 {{ISSN|0161-7370}}.<br />Golding Bird, [https://books.google.com/books?id=9FXVoGcVJygC&pg=PA440 "Advantages presented by the employment of a stethoscope with a flexible tube"], ''London Medical Gazette'', '''vol. 1''', pp. 440–12, 11 December 1840.</ref>

=== Binaural devices ===
In 1851, Irish physician Arthur Leared invented a binaural stethoscope. The following year, George Philip Cammann, a physician practicing in New York City, perfected for commercial production the design of a stethoscope that featured  a plug for each ear.<ref>{{cite journal|last1=Permin|first1=Henrik|last2=Norn|first2=Svend|title=Stethoscope—Over 200 Years|journal=Journal of Pulmonology and Respiratory Research|volume=3|pages=001–008|url=https://www.pulmonolrespirjournal.com/articles/jprr-aid1010.php|doi=10.29328/journal.jprr.1001010|doi-access=free}}
</ref> Although improvements have been made, his design has remained essentially unchanged ever since. Cammann also wrote a major treatise on diagnosis by auscultation, which the refined binaural stethoscope made possible. By 1873, there were descriptions of a differential stethoscope that could connect to slightly different locations to create a slight stereo effect, though this did not become a standard tool in clinical practice.

[[Somerville Scott Alison]] described his invention of the '''stethophone''' at the Royal Society in 1858; the stethophone had two separate bells, allowing the user to hear and compare sounds derived from two discrete locations.  This was used to do definitive studies on binaural hearing and [[auditory processing]] that advanced knowledge of [[sound localization]] and eventually led to an understanding of [[binaural fusion]].<ref name="Wade2008" />

The medical historian [[Jacalyn Duffin]] has argued that the invention of the stethoscope marked a major step in the redefinition of disease from being a bundle of symptoms, to the current sense of a disease as a problem with an anatomical system even if there are no observable symptoms. This re-conceptualization occurred in part, Duffin argues, because prior to stethoscopes, there were no non-lethal instruments for exploring internal anatomy.<ref>{{cite web|last=Duffin|first=Jacalyn|title=Big Ideas: Jacalyn Duffin on the History of the Stethoscope|url=http://ww3.tvo.org/video/182217/jacalyn-duffin-history-stethoscope|publisher=TVO|access-date=28 November 2012|archive-date=27 September 2013|archive-url=https://web.archive.org/web/20130927173037/http://ww3.tvo.org/video/182217/jacalyn-duffin-history-stethoscope|url-status=dead}}</ref>

Rappaport and Sprague designed a new stethoscope in the 1940s, which became the standard by which other stethoscopes are measured, consisting of two sides, one of which is used for the respiratory system, the other for the cardiovascular system. The Rappaport-Sprague was later made by [[Hewlett-Packard]]. HP's medical products division was spun off as part of Agilent Technologies, Inc., where it became Agilent Healthcare. Agilent Healthcare was purchased by [[Philips]] which became Philips Medical Systems, before the walnut-boxed, $300, original Rappaport-Sprague stethoscope was finally abandoned ca. 2004, along with Philips' brand (manufactured by Andromed, of Montreal, Canada) electronic stethoscope model. The Rappaport-Sprague model stethoscope was heavy and short ({{convert|18|-|24|in|cm|abbr=on}}) with an antiquated appearance recognizable by their two large independent latex rubber tubes connecting an exposed leaf-spring-joined pair of opposing F-shaped chrome-plated brass binaural ear tubes with a dual-head chest piece.
[[File:Early flexible stethoscopes.jpg|thumb|left|Early flexible tube stethoscopes. Golding Bird's instrument is on the left. The instrument on the right is the stethophone.<ref name="Wade2008" />]]
Several other minor refinements were made to stethoscopes until, in the early 1960s, [[David Littmann]], a [[Harvard Medical School]] professor, created a new stethoscope that was lighter than previous models and had improved acoustics.<ref>{{cite web |title=History of Littmann Stethoscopes at a glance |publisher=3M.com |url= http://solutions.3m.com/wps/portal/3M/en_US/Littmann/stethoscope/products/history/ |access-date=2010-01-25}}</ref><ref>{{US patent|3108652}}</ref> In the late 1970s, 3M-Littmann introduced the tunable diaphragm: a very hard (G-10) glass-epoxy resin diaphragm member with an overmolded silicone flexible acoustic surround which permitted increased excursion of the diaphragm member in a Z-axis with respect to the plane of the sound collecting area.<ref>{{US patent|3951230}}</ref> The left shift to a lower resonant frequency increases the volume of some low frequency sounds due to the longer waves propagated by the increased excursion of the hard diaphragm member suspended in the concentric accountic surround. Conversely, restricting excursion of the diaphragm by pressing the stethoscope diaphragm surface firmly against the anatomical area overlying the physiological sounds of interest, the acoustic surround could also be used to dampen excursion of the diaphragm in response to "z"-axis pressure against a concentric fret. This raises the frequency bias by shortening the wavelength to auscultate a higher range of physiological sounds.

In 1999, Richard Deslauriers patented the first external noise reducing stethoscope, the DRG Puretone. It featured two parallel lumens containing two steel coils which dissipated infiltrating noise as inaudible heat energy. The steel coil "insulation" added .30&nbsp;lb to each stethoscope. In 2005, DRG's diagnostics division was acquired by TRIMLINE Medical Products.<ref>{{cite web |url=http://www.trimline.us/ |title=TRIMLINE Medical Products |access-date=2010-01-25 |archive-date=2009-03-06 |archive-url=https://web.archive.org/web/20090306043019/http://www.trimline.us/ |url-status=dead }}</ref>{{Failed verification|date=February 2019}}