A stethoscope is one of the most important tools for doctors and medical professionals. It allows us to hear the internal sounds of the body, which can help with the diagnosis and treatment of various conditions.

But how does a stethoscope work?

A stethoscope consists of several parts that work together to allow practitioners to listen to the body’s internal sounds. In this article, we’ll take a closer look at the different parts of a stethoscope and how they work to produce clear, accurate sound.

What is a Stethoscope?

A stethoscope is a handheld medical device that healthcare professionals use to listen to the internal sounds of the body, such as the sounds of the heart and lungs.

It is composed of several different parts, each of which serves a specific purpose.

Parts of a stethoscope labeled

Stethoscope Parts

In order to understand how a stethoscope works, it is important to know the different parts of the instrument.

A stethoscope typically consists of the following parts:

  • Ear tips
  • Ear tubes
  • Tubing
  • Chest Piece
  • Stem
  • Diaphragm
  • Bell

Each part plays an important role in amplifying internal body sounds and making them easier for medical professionals to hear.

How Does a Stethoscope Work

When the chest piece of a stethoscope is placed against a patient’s skin, it picks up sound vibrations produced by the body.

For example, when the heart beats, it produces a “lub-dub” sound that can be heard using a stethoscope. This is caused by the rhythmic closure of the heart valves as blood is pumped through the chambers.

When this occurs, the vibrations travel through the chest piece and tubing, into the ear tubes, and then through the ear tips.

The ear tips of a stethoscope are designed to fit snugly into the practitioner’s ear canal, which allows the sound vibrations to be heard.

How Does a Stethoscope Work

Chest Piece

The chest piece, also known as the head of the stethoscope, has three parts:

  1. Diaphragm
  2. Bell
  3. Stem

The diaphragm is the round, metal disc that is placed against the patient’s skin. It vibrates when it picks up sound waves and transmits them through the stethoscope.

The bell is a small, cup-shaped piece that is placed on the skin. It is used to pick up lower-frequency sound waves. The stem is a metal piece that connects the diaphragm and bell.

Stethoscope chest piece parts

Tubing

The tubing refers to the long, thin tube that connects the chest piece to the ear tubes. It is typically made of rubber or plastic and is flexible, which allows the practitioner to position the chest piece in different ways.

As sound waves travel through the tube, the rubber material causes them to bounce off of the sides of the tubing.

Ear Tips

The ear tips are the small, cone-shaped pieces that fit into the practitioner’s ear canal. As long as they are inserted correctly into the ears with a proper fit, they should remain in place and allow the practitioner to hear the amplified sound.

Once sound waves and vibrations reach the ear tips, they can finally reach the practitioner’s eardrums for interpretation.

stethoscope ear tips and tubes

How to Use a Stethoscope

Now that we know the different parts of a stethoscope and how they work, let’s take a look at how to use this important tool.

When using a stethoscope, there are a few things to keep in mind:

  • The ear tips should fit snugly into the practitioner’s ear canal. If they are too loose, they will fall out and the sound will be muffled. If they are too tight, they will cause discomfort.
  • The chest piece should be placed directly against the patient’s skin. It should not be placed on top of clothing as this will muffle the sound.
  • The diaphragm should be used to pick up higher-frequency sound waves, while the bell should be used to pick up lower-frequency sound waves.
  • The stem should be positioned so that it is pointing towards the patient’s head. This will help the practitioner to hear the sound more clearly.

When using a stethoscope, it is important to remember that the quality of the sound will depend on a number of factors, such as the type of stethoscope, the positioning of the chest piece, and the patient’s body type.

For example, obese patients may have more tissue to contend with, which can make it more difficult to hear internal sounds. In these cases, it may be necessary to use a different position for the chest piece.

Who Needs to Know How a Stethoscope Works?

While it is always beneficial to have a basic understanding of how a stethoscope works, it is especially important for medical professionals who use this tool on a regular basis. This includes:

By understanding how a stethoscope works, these professionals will be better equipped to use this tool to provide better care for their patients.

respiratory therapist auscultation stethoscope

What is the Best Stethoscope?

If you work in the medical field and need a new stethoscope, we recommend the 3M Littmann Classic III Stethoscope.

This model is made of high-quality materials and provides clear sounds that can be easily heard. Not to mention, this stethoscope offers the best bang for your buck when it comes to quality and affordability.

To learn more, check out our full guide that reviews the best stethoscopes for medical professionals who regularly perform auscultation on their patients.  

This is our top-recommended stethoscope for medical professionals.

As an affiliate, we receive compensation if you purchase through this link.

Final Thoughts

A stethoscope is a handheld medical device used by practitioners to listen to the internal sounds of a patient’s body. If you work in the medical field, it’s important to understand how a stethoscope works.

First, you must learn about the most important parts, such as the chest piece, tubing, and ear tips.

The chest piece is placed against the patient’s skin and picks up sound waves, which then travel through the tubing and ear tips. The ear tips fit snugly into the practitioner’s ear canal, allowing them to hear the amplified sound.

Using a stethoscope correctly is important for providing high-quality care for your patients.

The quality of the sound will depend on a number of factors, such as the type of stethoscope, the positioning of the chest piece, and the patient’s body type.

By understanding how a stethoscope works and how to use it correctly, practitioners can provide better care for their patients. Thanks for reading!

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.

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Medical Disclaimer: The information provided by Respiratory Therapy Zone is for educational and informational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition.