STETHOSCOPE | PARTS, USES, METHOD, TYPES, HOW TO BUY

Hello there! Have you ever been curious about the tool that healthcare professionals use to listen to sounds from your heart, lungs, and other organs? It is called a stethoscope!

You will be learning everything you need to know about it, what are the name of parts, how to use it, method of using it and I have covered some myths and facts related to stethoscope in this post.

This article will also provide guidance on how to choose and buy the right stethoscope, considering factors such as price, durability, and performance.

A stethoscope is a clinical instrument which is used by physicians and other health care professionals.

Stetho = chest; Scope = to inspect

Main use of it is to listen the sounds produced in chest and anywhere in the body.

Listening to the sounds of body is known as Auscultation.

Auscultation with the help of stethoscope is called “Mediate auscultation”.

You might be thinking that as stethoscope is a very common device so what can be so new or interesting about it that you did not knew before!

But I promise, this post is going to be more interesting and informative for you.

Before I start describing the anatomical aspects of stethoscope, let us get some historical insights about it.

DISCOVERY OF STETHOSCOPE

There was a time when doctors were listening heart and lung’s sounds by placing their ear directly on the chest of the patient.

Many times, it was uncomfortable and inconvenient for the patient and doctors.

So, in 1819 a French physician Rene’ Laennec introduced a device to improve the accuracy of these examination and to make it easy to listen the sounds from different body parts.

STETHOSCOPES BY LAENNAE AND ARTHUR LEARED

FIRST STETHOSCOPE OF LAENNEC

  • Was made up of wooden cylinder.
  • Had a hole in center.
  • The one end of the cylinder was placed on the patient’s chest and listen through the other end.

EVOLUTION IN THE DESIGN OF STETHOSCOPE

  • In 1851 an Irish physician Arthur Leared improved the basic design introduced by Laennec.
  • It had two earpieces connected by a metal tube that allowed transmission of sound.
  • Introduction of diaphragm was in early 1900s. This has improved the quality and sensitivity of sound.
  • In the letter half of the 20th century electronic Stethoscope has been introduced. It has more noise reduction and amplification of Sound facilitating features.
  • Over the years, stethoscope has undergone several design improvements. for more than 200 yours, medical professionals have used it Worldwide.

UNDERSTANDING THE PARTS OF STETHOSCOPE

Mainly there are two types stethoscopes available

  1. Monaural- commonly used in obstetric practice to hear fetal heart sounds and therefore it is also called ‘Fetoscope’.
  2. Binaural- universally used.

As binaural type of stethoscope is very common now a days, here I am going to explain the anatomy of it in detail.

This instrument has 3 parts:

  1. THE CHEST PIECE
  2. THE EAR FRAME
  3. The RUBBER TUBING
STETHOSCOPE | PARTS, USES, METHOD, TYPES, HOW TO BUY

THE CHESTPIECE: UNDERSTANDING THE TWO TYPES AND THEIR BENEFITS

Chest piece is one of the important parts of a stethoscope because its role is important for the overall device performance.

Chest piece is available in two types

  1. The bell-shaped chest pieces
  2. The diaphragm type of chest piece

Both types have their benefits and limitations.

But medical students should be skillful in using both types for accurate diagnosis.

BELL AND DIAPHRAGM OF STETHOSCOPE

The bell-shaped chest pieces

Description

  • Conical in shape.
  • It has a rubber ring (as an insulating material to prevent cold touch of metal) that covers the mouth.
  • Relatively small in diameter, designed in such a way that can fit over almost any part of the body’s surface.
  • Bell shape of chest piece enables it to pick up low-pitched sound in compare to diaphragm type.

Benefits

  • Conducts original sound.
  • The small diameter of chest-piece lies snugly almost to any part of the body surface. Does not leave gap between chest-piece and skin.
  • Ideal for hearing low-pitched sounds.
  • Excellent for routine clinical examination.
  • Lesser chances of sound misinterpretation.

Limitations

  • Small size it limits its ability to detect sounds in hard-to-reach areas of body.
  • Does not amplify the sound.
  • Not ideal for noisy surroundings.

The diaphragm type of chest piece

  • Flat and larger side of stethoscope is diaphragm.
  • Made up of a thin, flexible celluloid material that vibrates in response to sound waves.

Benefits

  • Amplifies sounds, making them louder than the original sound.
  • Excellent for high-pitched sounds like murmurs and other cardiac sounds.
  • Ideal for routine clinical examination.

Limitations

  • Diaphragm may create unexpected additional sounds if rubbed against any surface such as hair and misguides the listener.

Functions of the chest pieces

Transmission of sound waves from patient’s body to the stethoscope’s earpiece.

Amplification of the sound is valuable for easy examination.

Bell shaped chest pieces should be used to hear missing notes by diaphragm. Therefore, combined chest-pieces are widely used they are also known as dual head stethoscopes.

The switching mechanism

STETHOSCOPE PARTS

There is a locking system at the neck of the chest piece.

You can rotate the chest piece clock-wise or anti-clock wise. So, diaphragm and bell can be switched according to your needs.

You can engage only one of them at a time (cannot be unlocked both at the same time). Only one side will be working at a time.

You can hear/feel a click when it is fully engaged.

THE EAR FRAME

  • The ear frame consists of two curved metallic tubes.
  • Joined together with a flat V-shaped spring which keeps them pulled together.
  • The upper end of the tube is curved so that, they correspond to the curve of external auditory meatus.
  • It runs medially, forwards & downwards so that, the horizontal limb enters the meatus and fit in without causing any unnecessary pressure on the walls of the meatus.
  • Two plastic knobs are placed on the tip of each tube that enter the meatus so that it fits snugly and preventing injury to the meatus wall.
  • Two rubber tubes connected with chest piece by a Y shaped metal tube.

THE RUBBER TUBING

  • Tubing of the stethoscope is made up of a flexible rubber like material.
  • Connects the earpieces to the chest piece.
  • Length of tube is usually sufficient to allow the examiner to move comfortably around the patient.

TYPES OF STETHOSCOPES

Several types of stethoscopes are available.

Each one of them has its own unique features and utilities.

Here are some most common types of stethoscopes listed below.

1. Acoustic stethoscope

  • Commonly used.
  • It has a chest piece with both diaphragm and bell.
  • Does not use any external power source for sound amplification.

2. Electronic stethoscope

  • Uses battery.
  • Sounds are amplified by power.
  • Often used in noisy environment.
  • Suitable for patients with a low heartbeats or weak lung sounds.

3. Fetal stethoscope

  • Special type of stethoscope used during pregnancy to listen fetal heart sounds.
  • Has large and flat chest piece in compare to traditional stethoscope.

4. Doppler stethoscope

  • Ultrasound waves are used to detect and amplify the sounds of blood flow.
  • Ideal to examine blood pressure or to detect abnormal characteristics of blood flow.

5. Pediatric stethoscope

  • It has smaller chest piece and short tube in compare to traditional stethoscope.
  • Specially designed to use on infants and young children.

6. Cardiology stethoscope

  • Has a larger chest piece with long tubing than a traditional one.
  • Designed for cardiologists who needs to listen the faint heart sounds.

HOW TO WEAR THE STETHOSCOPE?

  • Always clean the stethoscope between patients to avoid contamination.
  • Put the ear pieces of the stethoscope in your ears by adjusting them to fit comfortably.
  • Make sure the ear pieces are pointing forward.

HOW TO USE STETHOSCOPE?

It is important to use the stethoscope properly for accurate reading and to prevent misdiagnosis.

It is difficult to get comfortable with new instrument each time. So, students should carry their own stethoscope while learning on subjects in laboratory or on patients in hospitals.

  • Make the patient sit or lie in comfortable position.
  • The area to be examined should be exposed (clothing should be removed).
  • Choose an appropriate side of the chest piece (Diaphragm or bell) based on the type of examination you are going to perform.
  • Now place the chest piece firmly against the skin over the surface of organ you want to examine.
  • Diaphragm needs to press firmly. Bell requires light pressure comparatively.
  • Try to listen carefully and attentively via ear pieces.
  • Move the chest piece (do not slide) around the different body location to examine different area.
  • When finished remove the instrument, and wipe down the chest piece with alcohol or disinfectant.

HOW TO BUY A NEW STETHOSCOPE?

If you are planning to buy a new stethoscope of your own, there are some points that will help you to select the right one.

By following these steps, you will be able to select a stethoscope that satisfy the needs and budget of yours.

1.Consider your needs.

  • Think of what you will be using the stethoscope for? May be for general practice, cardiological examination, pediatrics, or obstetrics.
  • What type of instrument you wish to buy? Acoustic or electronic?
  • Choose the right features and abilities of stethoscope by reviewing the types available in the market.

2. Set a budget

  • Price of stethoscope can range from less than 500 INR to up to 30,000 INR.
  • Decide how much you can spend before you start shopping.

3. Research models and brands

  • You can look for reviews and ratings of other medical practitioners.
  • Consider the trusted brands such as, Littman, Welch Allyn, Omron, Microtone etc.

4. Check the warranty

  • Ask for the stethoscope that comes with a reasonable warranty that may cover defects or damage.

5. Try before you buy

  • If possible, try out different types in person and look for the one that feels the most comfortable and produces the clearest sound.

6.Look for the additional features

  • Some stethoscopes come with additional features like tunable diaphragm, noise reduction system or Bluetooth connectivity.
  • Most comes with an extra pair or diaphragm and ear knobs for future replacement.

HOW TO CHECK THE QUALITY OF STETHOSCOPE?

After all you do not want to end up buying a wrong piece of instrument.

Sometimes, the piece may be looking okay from the outside but there are chances that it may not function appropriately or up to the mark.

So, how do you confirm that your stethoscope is technically manufactured without any defects?

Check the chest piece

  • It should be comfortable and easy to use.
  • The locking system to switch between diaphragm and bell should be working properly, neither too hard nor too loose.
  • Check that chest piece gets engaged properly.

Evaluate the tube

  • The tubing structure should be durable and flexible.
  • Should be easy to clean.
  • Should not have any curls or cracks in between.

Check for the diaphragm

To check the sensitivity of diaphragm, follow these steps.

  • First, put on the earpieces of the stethoscope.
  • Then, place the flat part of the chest piece against the palm side of your middle three fingers.
  • Be careful not to push down on your fingers, they should just rest on the flat surface of the chest piece.
  • Next, use your other hand to gently rub or tap on the back of the fingers that are touching the chest piece.
  • Finally, listen closely to the sounds you hear through the stethoscope.
  • A clear, crisp, distinct and amplified sound should be heard.
  • It should not be cracking, static or distorted.
  • If you hear very faint sound or no sound at all, it may indicate that the diaphragm is not sufficiently sensitive, damaged, dirty or worn out.

Note: a practicing physician should regularly check the sensitivity of diaphragm to ensure the proper functioning of stethoscope.

MYTHS AND FACTS ABOUT STETHOSCOPE

Let me explain some common myths about stethoscopes and the truth:

Myth 1: You can hear through clothes or barriers with a stethoscope.

  • Fact: No, the stethoscope needs to touch the skin directly to work properly.

Myth 2: Stethoscopes need to be warmed up before using.

  • Fact: Actually, you do not need to warm up the stethoscope. Just put the flat part against your palm or a flat surface for a moment.

Myth 3: Electronic stethoscopes are always better than traditional stethoscopes.

  • Fact: Electronic stethoscopes have some advantages, but traditional stethoscopes are still good and trustworthy.

Myth 4: You should clean the stethoscope after every use.

  • Fact: You should clean and disinfect your stethoscope regularly, but not necessarily after every use.

Myth 5: You can use the stethoscope as a hammer.

  • Fact: No, the chest piece is not made for hammering things, and it can damage the stethoscope if you do that.