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The stethoscope is a diagnostic device used for auscultation of the patient, mainly the chest, heart and abdominal cavity. A stethoscope is one of the basic tools of internists' work, but cardiologists and even anesthesiologists also use stethoscopes. What types of stethoscopes are there? How has the stethoscope been used in medicine?

Stethoscopeis a medical handset in the form of a funnel-shaped tube. Thestethoscopeconsists of a head (funnel and diaphragm that contact the chest), wires (connecting the head to the lyre), a lyre (conducting sound to each ear) and soft olives that the doctor puts it in his ear.

The stethoscope is believed to have been invented by the French physician René Théophile Hyacinthe Laennec (René Laennec) in 1816. Initially, it was a handset in the form of a wooden, funnel-shaped tube with a flat end on the ear side. Despite the fact that the stethoscope is over 200 years old, it is still the basic tool of the work of doctors, not only those of the first contact. Moreover, work on its improvement is still ongoing.


  1. Stethoscope - types of stethoscopes
  2. Stethoscope - how does it work?
  3. Stethoscope - heart examination
  4. Stethoscope - lung examination
  5. Stethoscope - blood pressure measurement
  6. Stethoscope - a source of bacteria
  7. Stethoscope cooperating with a smartphone

Stethoscope - types of stethoscopes

1. Acoustic stethoscopes:

  • anesthetic stethoscope - designed to measure blood pressure. Therefore, their head should be light, flat, so that it can be easily slipped under the cuff of the blood pressure monitor or under the patient's clothing and the pressure can be measured quickly and efficiently
  • internal stethoscope - there are not only those intended for adults, but also the pediatric, neonatal (neonatal) and infant versions. This type of stethoscope is used to auscultate the patient's heart and lungs, detect arterial blood supply disorders, test intestinal peristalsis
  • cardiac stethoscope- these are stethoscopes with the most sensitive and sensitive two-tone diaphragm, which allows you to auscultate the full range of tones - from the lowest to the highest. Excellent quality of auscultation will allow you to detect the slightest disturbances in the patient's heart work

2. Stethoscopeselectronic (digital) - intended for in-depth diagnostics of heart and lung tones.

Stethoscope - how does it work?

The funnel of the stethoscope, when held with moderate pressure on the chest, transfers all sounds produced in the chest, both low and high frequencies, with slight attenuation.

Stethoscope - heart examination

Murmurs, whistles and whistles form complex music flowing from the depths of the body. Using the sensitive membrane of the stethoscope, a trained ear of a specialist will recognize, for example, a heart defect at an early stage, when other symptoms may not yet be associated with it.

Auscultation begins with examining the heart. The doctor analyzes its beating at four points, over which the work of the four valves can be detected. The test is performed in a sitting position, although sometimes you auscultate while lying down or tilting (the change of position strengthens some sounds of heart disease).

The doctor examines while breathing, then while holding the breath: the heart beats slower then and its disturbances can be heard better. If any of the tones are weakened or disappear, this may indicate a narrowing of the valve.

When, in addition to the usual two tones, abnormal third and fourth sounds appear, it is a sign that the examined person may have a heart defect, e.g. left ventricular failure.

If, apart from the normal tones, murmurs are heard, the doctor determines the phase of the heart's work and its intensity. The source of such sounds may be valve stenosis or regurgitation.

Stethoscope - lung examination

During the stethoscope examination, the doctor also auscultates the lungs, symmetrically at the front and back. You can hear a respiratory murmur in he althy people. If it seems louder at some points, it may be a sign of an infiltration of the lungs that occurs with inflammation.

Stethoscope - blood pressure measurement

Measurement with a traditional blood pressure monitor using a stethoscope is considered to be more accurate than the results obtained with an electronic device. It wraps the arm and pumps air to compress the artery until the pulse stops. After a while, the doctor releases the pressure and listens to the pulsation of the blood to determine the systolic and diastolic pressure values.

Stethoscope - a source of bacteria

The stethoscope can be a source of infections. This was the conclusion of Israeli scientists from Tel Aviv University .¹ In their study, bacteria were grown out of 55 stethoscopes of pediatricians working in 12 different clinics. All stethoscopes were colonized with microorganisms. Staphylococci were isolated from 85.4 percent. stethoscopes. Methicillin-resistant staphylococcus was found infour stethoscopes. Alcohol cleaning reduced the number of colonies by an average of 96.3%.

Similar studies were carried out by American scientists from St. Joseph's High School (Pennsylvania). They isolated a total of 184 bacterial cultures from 92 stethoscopes, including methicillin-resistant staphylococcus aureus - MRSA. They also concluded that washing the hands and stethoscope head with disinfectants significantly reduces the amount of bacteria and thus the risk of infection in the patient .²

Stethoscope cooperating with a smartphone

The stethoscope has been helping to diagnose patients since the 19th century and scientists are still working on improving it. In Poland, two Polish research institutions are involved in it: the Department of Intelligent Technologies of the Polish Academy of Sciences and the Department of Room Acoustics and Psychoacoustics of the Adam Mickiewicz University in Poznań.

Doctors of physics from the Adam Mickiewicz University, who in cooperation with a software development company, developed an intelligent stethoscope. They called it StethoMe. It is the world's first electronic, wireless stethoscope that works with a smartphone, with a built-in thermometer and an intelligent sound analysis system. The tool is able to record and pre-interpret the sounds that you hear when you use it to test the work of the lungs or the heart. It only has the head, that is, the part you put on the body. It is cable-free and the so-called lira, but it has a display on which messages appear.

The device works in conjunction with the mobile application, the patient can quickly auscultate the lungs and heart and send the results to the doctor.

This device sends a simple message that something is happening in the lungs, the doctor receives a recording and graphical data, and he makes the diagnosis. All thanks to the algorithms that are able to make a preliminary interpretation - is the signal correct or you should contact a doctor.

The examination with the use of an intelligent stethoscope begins with the launch of a dedicated application and filling in the questionnaire on the smartphone according to the instructions displayed on the screen. Then the temperature is measured by dragging the stethoscope twice over the forehead - the device has a built-in thermometer. This is important because the temperature is closely related to the frequency of inhaling or exhaling.

In turn, scientists from the Polish Academy of Sciences want to construct a new generation digital stethoscope, which is to process sounds so that the doctor can hear all disturbing signals arising in the patient's body more clearly.


1. HA. Cohen, J. Amir, A. Matalon, R. Mayan, et al. Stethoscopes and otoscopes - a potential vector ofinfection ?. Family Practice. 14 (6), pp. 446-9, Dec 1997,

2. A. Schroeder, MA. Schroeder, F. D'Amico. What's growing on your stethoscope? (And what you can do about it)… Journal of Family Practice. 58 (8), pp. 404-9, Aug 2009,

3. The stethoscope is over 200 years old. Polish scientists improve it, refaja-go-polscy-naukowcy,181684,11,2.html

The text uses excerpts from Joanna Karwat's article from the "Zdrowie" monthly.

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