all about stethoscope- History, invention, modification, parts, uses etc

1. Dr. Sunil Natha Mhaske
M.B.B.S., M.D. (Paediatrics), M.B.A. (Hospital Administration),and M. A. (Public
Administration). PhD (Paediatrics) Scholar
Dean
Dr. Vithalrao Vikhe Patil foundation’s Medical College and Hospital, Ahmednagar,
Maharashtra. (India).
“Best Teacher Award and Dr. Sharadini Dahanukar Best of Best Teacher award by
Maharashtra University of Health Sciences, Nasik.”
Stethoscope

2. On occasion of Mothers Day…..
Dedicated to-

3. • The stethoscope is an acoustic medical
device for auscultation, or listening to internal
sounds of an animal or human body.
• The word stethoscope is from the Greek words
stethos, meaning chest, and skopein, meaning
to explore.

4. • Stethoscope is a symbol of healthcare professionals.
• Healthcare providers are often seen or depicted wearing a
stethoscope around the neck.
• 2012 research paper claimed that the stethoscope, when
compared to other medical equipment, had the highest
positive impact on the perceived trustworthiness of the
practitioner seen with it.

5. • Born on 17 February 1781
• French physician and musician.
• At the Necker-Enfants Malades Hospital in Paris.
Great inventory-
Rene Theophile Hyacinthe

7. Laennec was not comfortable by placing his ear directly onto a
woman's chest to listen to her heart……

10. A L’Hopital Necker, Ausculte
Un Phtisique (Laënnec, at the
Hopital Necker, Examining a
Consumptive Patient by
Auscultation).
Painting by Théobald
Chartran (1849–1907).
Photo courtesy of the US
National Library of Medicine.

11. • In 1816- during a cool morning, while walking in the courtyard of the Le Louvre Palace in
Paris, Dr. Rene Theophile Hyacinthe Laënnec, observed two children sending signals to
each other using a long piece of solid wood and a pin.
• With an ear to one end, the child received an amplified sound of the pin scratching the
opposite end of the wood.
• Later that year, Laënnec was called to a young woman with “general symptoms of a
diseased heart.”
• Both application of his hand to the chest and percussion offered little diagnostic
assistance.
• Laënnec was reluctant to start immediate auscultation (placing the doctor’s ear on the
patient’s chest) because of the age, sex and plumpness of the patient.
• In this moment of embarrassment, Laënnec recalled his observation of the children’s wood
borne signaling.

12. • It was this observation that inspired Laënnec’s invention of the
stethoscope.
• Laënnec spent the next 3 years testing various types of materials
to make tubes, perfecting his design and listening to the chest
findings of female patients with pneumonia.
• After careful experimenting, Laënnec decided upon a hollow
tube of wood, 3.5 cm in diameter and 25 cm long, which was the
forerunner of the modern stethoscope.
• His instrument was fitted with a plug when used to listen to the
heart and to make it portable, was made in parts that could be
disassembled.

13. • Laennec called this device as a "stethoscope“
• stetho- + -scope "chest scope"
• He called its use "mediate auscultation", because it was auscultation with a tool
intermediate between the patient's body and the physician's ear.

14. Model of Laënnec’s stethoscope from the 2nd edition of his famous book “De L’Auscultation Médiate”, published in
the year of his death. 1: (from left to right) Cylinder, 2: Longitudinal section through the stethoscope, 3: Longitudinal
section without chestpiece, 4: Chestpiece, 5: Lower part of the stethoscope, 6: Diameter of the stethoscope

16. • Laënnec’s stethoscope revolutionized diagnosis of diseases of the chest.
• His name is eponymously associated with micronodular cirrhosis of the liver (Laënnec’s cirrhosis).
• Laënnec was the first to lecture on melanoma in 1804.
• Laënnec distinguished two heart sounds, attributing the first heart sound to ventricular systole and the second
sound to atrial systole.
• He wrote the first descriptions of bronchiectasis and cirrhosis, and classified pulmonary conditions.
• He described murmurs and thrills, bronchial and vesicular breathing, pectoriloquy (as a sign of tubercular
cavities), egophony, bronchophony, a variety of rales, and normal and abnormal lung sounds.
• Laennec's pearls refer to sputum produced by asthmatics.
• Hamman's murmur, also known as Laënnec–Hamman symptom, Laënnec–Müller–von Bergmann–Hamman
symptom, or Hamman's crunch is a crunching sound heard over the precordium due to spontaneous mediastinal
emphysema.
• At the Université Claude Bernard Lyon 1 one of the four medical schools is named after Laennec.

18. Laënnec statue on the Place de la Cathedrale in Quimper
(Brittany), his place of birth.
The old seminary in Quimper, used as hospital, which received the name Laënnec in
1949 (today a retirement home under the name “Residence Manoir Laënnec). The
newly built Center Hospitalier of Quimper carries the name Théophile René
Laënnec.

19. He died of tuberculosis at the age of 45 on 13 August 1826

20. • Born on 9 December 1814
• British medical doctor and a Fellow of the Royal College of Physicians.
• He became a great authority on kidney diseases and published a
comprehensive paper on urinary deposits.
• 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.
Golding Bird

21. • Bird's invention is similar to the modern stethoscope, except that it
has only one earpiece.
• Bird found the flexible stethoscope convenient as it avoided
uncomfortably leaning over patients (as would be required by a rigid
stethoscope) and the earpiece could be passed to other doctors and
students to listen.
• It was particularly useful for Bird, with his severe rheumatism, as he
could apply the stethoscope to the patient from a seated position.
• He died on 27 Oct 1854 (aged 39) Fordwich, City of Canterbury,
Kent, England.

22. • Irish physician and traveler of the world.
• Born in Wexford, Ireland in 1822 and was educated at Trinity College, Dublin.
• He graduated with a B.A. in 1845, am M.B. in 1847, and M.D. in 1860
• In 1851, he invented a binaural stethoscope.
• He died on 16th October 1879.
Arthur Leared

23. Born on September 07, 1804 in
Greenwich Village, Manhattan, New
York, New York, United States
In 1852, George Philip Cammann
perfected the design of the
stethoscope instrument (that used both
ears) for commercial production,
which has become the standard ever
since.
George Philip Cammann

24. • Camman Stethoscope Set-
- The tubing is covered with a woven cotton
sleeve.
- The tubes are connected to an ivory ball with
a threaded pedestal onto which other bells
can be attached.
- The set also includes separate tubes covered
with the same cotton sleeve, each bearing a
bell at one end.
- There are two detachable bells .
• Cammann also wrote a major treatise on
diagnosis by auscultation, which the refined
binaural stethoscope made possible.
• Died in February 14, 1863 (58)

25. • Scottish physician.
• He invented a " differential stethoscope " and wrote a book on
Physical Examination of the Chest in Pulmonary Consumption and
its Intercurrent Diseases (1860).
• He 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 lead to an understanding of binaural fusion.
Somerville Scott Alison

26. • Two chest pieces make this design different
from the standard binaural stethoscope.
Sounds from two different areas of the body
could be heard simultaneously and
compared.
• It also gave the physician a better chance of
pinpointing the source of a sound.
• He was an expert in both pulmonary
tuberculosis and heart disease.
• However, his instrument was not of much
use and therefore not widely used.

27. 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 model stethoscope was heavy and short
(46–61 cm) 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.
Rappaport and Sprague

28. David Littmann
• Born on July 28, 1906, in Chelsea Massachusetts.
• American cardiologist
• Harvard Medical School professor and researcher.
• The name Littmann is well known in the medical field for the patented
Littmann Stethoscope reputed for its acoustic performances for
auscultation.
• With Gus Machlup, Dr. David Littmann founded Cardiosonics, Inc. to
sell his stethoscopes.
• At that time the stethoscope line consisted of two key models, the
doctor's stethoscope and the nurse's stethoscope.
• 3M acquired the stethoscope company on April 1, 1967, and hired Dr.
Littmann as a consultant.
• 3M currently produces the range of Littmann brand stethoscopes.

29. • Between 1967 and 1970, the Littmann range had expanded to 10
models. The tubing color was limited to gray and black, but tubing length
was now available in 22″ or 28″.
• By the mid 1970’s, six major lines featuring a total of 40 models were
available.
• The late 1970’s saw the introduction of the 3M Littmann Cardiology
stethoscope. 50 of the world’s leading cardiologists were asked to design
the ultimate stethoscope. The “dream” stethoscope featured dual lumen
(two tubes in one) softer ear tips and a deeper bell for enhanced low
frequency sounds.
• In the medical field, Dr. David Littmann’s name stands for innovation
and revolutionizing cardiology – and as it’s namesake, the Littmann
Stethoscope is the gold-standard by which other stethoscopes are judged
against. The Littmann name means superior design and innovation, and
exceptional acoustics and performance.
• He Died on – January 1, 1981

31. Parts of a binaural stethoscope

32. CHEST PIECE
• The chest-piece or head of the stethoscope is composed of the connected stem,
diaphragm and/or bell.
• Some models of stethoscope have a one-sided chest piece with a tunable diaphragm.
• Others have a two-sided (double-headed) chest piece with a diaphragm on one side
and a bell on the other.
• Most chest-pieces work best when applied against the patients skin, however some
stronger, high quality stethoscopes may be able to pick up sounds through thin
layers of clothing.
• The chest-piece part of the stethoscope is used to listen to patient sounds by placing
the diaphram or bell end of the chest-piece on the patients chest, back or stomach.
STEM
• The stem is basically the metal/steel part of the stethoscope that connects the stethoscopes tubing to the chest-
piece.
• Aside from connecting the two components of the stethoscope it also allows the user to switch/click between
the chest-pieces diaphragm and bell by turning the chest-piece and clicking it into place via the ball bearing.
• Rotating the two-sided chestpiece on the stem selects or “indexes” which diaphragm is open to the acoustic
path.

33. DIAPHRAGM
• The diaphragm is the large circular end of the chest-piece.
• Some diaphragms feature a non-chill, hypoallergenic diaphragm in order to ensure
maximum comfort for the patient being observed.
• The larger diaphragm side is normally used for adult patients.
• The smaller-diameter bell is best for Paediatric or thin patients, for maneuvering around
bandages, and for carotid assessment.
• This side of device allows medical professionals to listen to a wider area of the patients
body and picks up higher frequency sounds than the bell half of the chest-piece.
BELL
• The bell is the smaller circular end of the chest-piece.
• This side of the device focuses on a narrower range listens for lower-frequency sounds
that may not easily be detected by the diaphragm.
• As with the diaphragm the bell may also feature a non-chill, hypoallergenic design to
provide patients with additional comfort while they are being listened to.

34. TUBING
• The soft flexible line of the stethoscope is known as its tubing.
• It is relatively short.
• The next-generation tubing provides improved resistance to skin oils and alcohol for longer
tubing life.
• No natural rubber latex or phthalate plasticizers are used in the tubing or any other
component—to help protect human health and the environment.
• Depending on the stethoscopes make and model the tubing may be made with a single tube
or dual lumen tube design that connects to the metal/steel eartubes.
• A good stethoscope will usually come with a dual lumen design and tubing that is sectioned
off into left and right hemispheres so that the diaphram/bell sounds can travel from the head
of the device to the users ears with the most accuracy and acuity.
• Stethoscopes have double lumen tubing: two sound paths inside one outer tube which helps
eliminate the rubbing noise generated by traditional twin-tubed stethoscopes.
• The purpose of the tubing is to maintain and transfer the frequency / sound level that is
captured by the diaphram or bell and send it to the eartubes where it can make its way to the
users ears.

35. HEADSET
• The headset is the combined components of the upper half of the stethoscope
which include the two eartubes, tension springs and eartips.
• All of the components are designed together to form a comfortable alignment in
the users ears and are angled in a way that provides maximum sound quality
throughout the headset.
• When viewed from the side the eartips of the headset can be seen pointed toward
the users nose while the eartubes hang back slightly.
• This allows sound to flow efficiently into the ear canal so that their is minimal
disturbance from the stethoscope.
TENSION SPRINGS
The headset tension is adjusted for individual fit and comfort by pulling the eartubes apart to reduce the
tension, or squeezing them together (crossing them over) to increase tension.

36. EARTUBES
• The eartubes are the metal/steel parts of the stethoscope that connect to the eartips and the synthetic/PVC
tubing, which connects to the stem of the chest-piece.
• The eartubes are designed to isolate and transfer sound to the users ears with minimum quality loss.
• These metal/steel eartubes help separate sounds into left and right channels in order to provide a better
sound experience, which allows the user to more easily diagnose their patients medical condition.
• The eartubes are positioned at an anatomically correct angle, for a proper fit into your ear canals.
• The ribbed ends of the eartubes snap the eartips on tight for safety.
• Eartubes on a Littmann stethoscope are made of an aerospace aluminum alloy that provides both strength
and lighter weight.
• The bottom section of the eartubes connect to the stethoscopes tubing line where it receives the incoming
sounds.

37. EAR TIP
• The eartips of a stethoscope is the part that goes into the users ear where they
receive the sounds that come from the chest-piece.
• The eartips are generally made out of rubber or silicone material and are
designed to create a form fitting seal inside of the ears so that unwanted sounds
stay out.
• A good pair of comfortable eartips are very important for users who spend a lot
of time checking their patients health with their stethoscopes as it can make all
the difference between a comfortable experience and an irritating or painful one.
• All eartips are made with a soft, flexible material that is structured to fit and
cradle the inner ears, a clear whole in the center so that the sound can easily
transfer through them, and either a rigged or smooth interior on the opposite end
of the eartips where the top end of the stethoscopes eartubes slide in.

38. An electronic stethoscope (or stethophone) overcomes
the low sound levels by electronically amplifying body
sounds.
Electronic stethoscopes are also used with computer-
aided auscultation programs to analyze the recorded
heart sounds pathological or innocent heart murmurs.

39. • Some electronic stethoscopes feature
direct audio output that can be used with
an external recording device, such as a
laptop or MP3 recorder.
• The same connection can be used to listen
to the previously recorded auscultation
through the stethoscope headphones,
allowing for more detailed study for
general research as well as evaluation and
consultation regarding a particular
patient's condition and telemedicine, or
remote diagnosis.
• There are some smartphone apps that can
use the phone as a stethoscope.

40. • At least one uses the phone's own microphone to amplify sound, produce a visualization,
and e-mail the results. These apps may be used for training purposes or as novelties, but
have not yet gained acceptance for professional medical use.
• The first stethoscope that could work with a smartphone application was introduced in
2015.

41. • A fetal stethoscope or fetoscope is an acoustic stethoscope
shaped like a listening trumpet.
• It is placed against the abdomen of a pregnant woman to listen
to the heart sounds of the fetus.
• The fetal stethoscope is also known as a Pinard horn after French
obstetrician Adolphe Pinard (1844–1934).

42. • A Doppler stethoscope is an electronic device that measures the Doppler effect of
ultrasound waves reflected from organs within the body.
• Motion is detected by the change in frequency, due to the Doppler effect, of the reflected
waves.
• Hence the Doppler stethoscope is particularly suited to deal with moving objects such as a
beating heart
Doppler stethoscope

43. 3D-printed stethoscope-
• It is an open-source medical device meant for auscultation
and manufactured via means of 3D printing.
• The 3D stethoscope was developed by Dr. Tarek Loubani
and a team of medical and technology specialists.
• The 3D-stethoscope was developed as part of the Glia
project, and its design is open source from the outset.
• The need for a 3D-stethoscope was borne out of a lack of
stethoscopes and other vital medical equipment because of
the blockade of the Gaza Strip, where Loubani, a
Palestinian-Canadian, worked as an emergency physician
during the 2012 conflict in Gaza.
• The 1960s-era Littmann Cardiology 3 stethoscope became
the basis for the 3D-printed stethoscope developed by
Loubani.
Tarek Loubani
Canadian doctor and humanitarian.
He developed a low-cost stethoscope in
2015.

44. Stethoscope ceremony

45. Respect to Stethoscope

47. References-
1. https://en.wikipedia.org/wiki/Stethoscope
2. Rene Theophile Hyacinthe Laënnec (1781–1826): The Man
Behind the Stethoscope, Ariel Roguin, Clin Med Res. 2006
Sep; 4(3): 230–235. doi: 10.3121/cmr.4.3.230
3. https://www.littmann.com/3M/en_US/littmann-
stethoscopes/education-center/history/
4. https://www.smartmedicalbuyer.com/blogs/smb-blog/a-brief-
history-of-stethoscopes.
5. https://www.adctoday.com/learning-center/about-
stethoscopes/history-stethoscope
6. Stethoscope - Over 200 years, Henrik Permin* and Svend
Norn, Department of Respiratory Diseases, Bispebjerg
Hospital, Dk-2400, Copenhagen, Denmark