A stethoscope is an essential tool for medical professionals. It helps them listen to the sounds within the body, which is important when it comes to diagnosing and treating patients.
But how exactly does a stethoscope work?
In order to understand how to properly use a stethoscope, it’s important to know the different parts of the instrument and how they work.
Download our free guide that has over 100+ of the best tips for healthy lungs.
Why are the Parts of a Stethoscope Important?
The parts of a stethoscope are crucial for precise sound detection and transmission. Each component is designed to capture internal bodily sounds with clarity, ensuring accurate diagnosis and monitoring. Without its meticulously crafted parts working in harmony, the stethoscope wouldn’t effectively serve its fundamental purpose in medical practice.
Parts of a Stethoscope Labeled
A stethoscope is made up of several parts, including the following:
- Ear tips
- Ear tubes
- Tubing
- Chest Piece
- Stem
- Diaphragm
- Bell
Note: Each part serves a specific purpose and fits together to make up a stethoscope, which is one of the most useful tools in the medical field.
What are the Parts of a Stethoscope and Their Functions?
Ear Tips
Ear tips are the plastic or silicone buds at the top of the stethoscope that rest in your ear. Most stethoscopes come with two or three different sizes of ear tips. Picking the wrong size can affect the sounds you hear with a stethoscope.
A size too small can impair the sound quality, and a size that is too big can irritate your ears.
If you find that the earpieces that came with your stethoscope aren’t comfortable or don’t fit properly, there are several companies that sell ear tips of different shapes, sizes, and materials.
Replacement earpieces for stethoscopes are available and can be purchased separately.
Keeping the ear tips clean is important. If they happen to become clogged with ear wax or debris, it can alter the sounds that you hear.
This is why it’s important to clean the earpieces regularly with alcohol wipes.
Ear Tubes
The ear tubes are the metal pieces that connect the earpieces to the tubing of a stethoscope. They’re often made of steel.
This is the part of a stethoscope that is responsible for holding the ear tips and providing the left and right pathways for sound to travel through.
They contain tension springs that rest between the ear tubes. These springs enable you to adjust how tight your stethoscope is sitting on your ears by either pulling the ear tubes together or pushing them apart.
You must adjust the tension to make a proper seal, but not too much because you don’t want it to be uncomfortable during use.
Tubing
There’s a lot more that goes into the tubing of a stethoscope other than pretty colors and designs. The tubing plays an important role in facilitating how the sounds travel from the chest piece to your ears.
Stethoscope tubing is typically made of PVC, and it can have a single-lumen or double-lumen.
Single-lumen stethoscopes have one tube that connects directly to the chest piece and splits into left and right sides. Double-lumen stethoscopes, on the other hand, have two individual tubes.
Replacement tubing for stethoscopes is available and can also be purchased separately.
When choosing a stethoscope, you want to pick one with tubing that is thick enough to block out external sounds. If the tubing is too thin, it can impact the quality of sounds that you hear.
Tubing length is also important. In general, it’s best to select tubing that is 25 to 35 cm in length. Tubing that is shorter than 25 cm may not allow you to auscultate the patient from a comfortable distance.
However, if the tubing is longer than 35 cm, this too can diminish the quality of sound that you hear. If your stethoscope tubing becomes damaged, you can often purchase replacement tubing rather than investing in a whole new stethoscope.
Chest Piece
The chest piece is sometimes referred to as the head of the stethoscope. It’s the part that is placed on the patient’s body in order to hear sounds during auscultation.
The chest piece is made up of the following:
- Stem
- Diaphragm
- Bell
Dual-sided chest pieces will have both a diaphragm and a bell, while a single-sided chest piece will only have a diaphragm.
Modern stethoscopes typically have diaphragms and bells that are made of a metal base that sits around a plastic disk.
Diaphragm
When compared to the bell, the diaphragm is larger in diameter and picks up higher-frequency noises, such as breath sounds.
Once placed against a patient’s skin or clothing, the sounds produced by a patient will make the disk vibrate. It is these vibrations that are responsible for creating the sounds that you hear through the device.
Bell
The bell, on the other hand, is smaller and picks up lower-frequency noises, such as heart murmurs.
Because bells are smaller in size, they are also often used to listen to the breath sounds of pediatric patients.
Stem
The stem is the metal piece that connects the diaphragm and bell to the tubing. If you own a dual-sided stethoscope, this part will enable you to rotate the head of the stethoscope and alternate between using the diaphragm and bell.
Some companies sell stethoscopes with diaphragms and bells that are made of hypoallergenic and non-chill materials to increase patient comfort.
How Does a Stethoscope Work?
A stethoscope, a familiar tool in the realm of medicine, operates based on simple acoustic principles but plays a crucial role in facilitating the early diagnosis and monitoring of numerous ailments.
At its essence, a stethoscope captures, transmits, and amplifies sounds emanating from within the body, especially those from the heart, lungs, and gastrointestinal system.
The primary component responsible for sound detection is the chestpiece, which typically comprises two sides: the diaphragm (a flat, sealed surface) and the bell (a concave, open component).
When placed against a patient’s skin, the diaphragm picks up higher-frequency sounds such as the normal beating of the heart.
On the other hand, the bell is adept at detecting lower-frequency sounds, like heart murmurs. The vibrations caused by these internal sounds are then transferred to the air inside the tubing of the stethoscope.
The stethoscope’s tubing, made from a material that minimizes sound loss, acts as a conduit, channeling these sound waves from the chestpiece to the listener’s ears. The length and construction of this tubing are engineered to preserve the integrity of the captured sounds, ensuring that extraneous noises are minimized.
At the end of this tubing lie the ear tubes and ear tips. The ear tubes, usually made of a rigid metal, direct sound towards the ear tips.
These ear tips, designed to fit snugly within the user’s ear canal, help to create a seal that both enhances the received sounds and prevents external noise interference.
Summary: The stethoscope’s operation is a seamless integration of its parts and acoustic principles. When the chestpiece collects bodily sounds, they travel as vibrations through the tubing and are eventually channeled into the ears of the healthcare professional, offering a clear and magnified acoustic snapshot of the patient’s internal state.
FAQs About Stethoscope Parts
What are the Basic Components of a Stethoscope?
The basic components of a stethoscope include the ear tips, ear tubes, tubing, and chest piece. The ear tips and ear tubes are responsible for holding the stethoscope in place and providing a pathway for sound to travel from the chest piece to your ears.
The tubing is what carries the sound from the chest piece to the ear tips and is typically made of PVC.
The chest piece is placed on the patient’s body and contains a diaphragm and bell that are used to pick up different types of sounds.
What is the Most Important Part of a Stethoscope?
The most important part of a stethoscope is the chest piece, as it is responsible for picking up the sounds produced by the patient’s body.
The chest piece contains a diaphragm and bell that are used to pick up different types of sounds.
What is the Difference Between a Single-Sided and Dual-Sided Stethoscope?
A single-sided stethoscope will only have a diaphragm, while a dual-sided stethoscope will have both a diaphragm and a bell. The stem is the metal piece that connects the diaphragm and bell to the tubing.
If you own a dual-sided stethoscope, this part will enable you to rotate the head of the stethoscope and alternate between using the diaphragm and bell.
What is the Difference Between a Diaphragm and a Bell?
A diaphragm is larger in diameter and picks up higher-frequency noises, such as breath sounds. The bell, on the other hand, is smaller and picks up lower-frequency noises, such as heart murmurs.
Because bells are smaller in size, they are also often used to listen to the breath sounds of pediatric patients.
What is the Best Stethoscope?
When selecting the best stethoscope, it’s important to take into consideration the price and quality. When it comes to getting the best bang for your buck, our top recommendation is the 3M Littmann Classic III Stethoscope.
It’s a high-quality stethoscope that’s durable and comes with a variety of features, such as adjustable pressure-sensitive diaphragms, a non-chill rim, and multiple frequency response settings.
Balancing acoustic performance, durability, and affordability, this stethoscope is our top recommendation for a wide range of healthcare professionals.
How to Clean a Stethoscope?
The parts of the stethoscope, at times, are delicate. They are made of materials that can become damaged if they are not properly cleaned.
That is why it’s important to know the proper techniques for cleaning a stethoscope.
Here are some of the most common mistakes users make when cleaning:
- Immersing the stethoscope in any kind of fluid
- Using hand sanitizer to cleanse the device
- Using an autoclave for sterilization
You should avoid these if you want to avoid causing damage to your stethoscope.
To clean it properly, you should use 70% isopropyl alcohol, 2% bleach solution, or mild soap and water when cleansing your stethoscope.
This can safely disinfect the device without damaging any of the materials.
Note: To prevent spreading infection from patient to patient, you should wipe your stethoscope down between each patient contact.
Final Thoughts
A stethoscope is a vital piece of equipment for most medical professionals. It allows healthcare professionals to listen to the internal sounds of the body, which is essential in diagnosing and treating various of conditions.
The parts of a stethoscope include the eartips, ear tubes, tubing, and chest piece. Each part plays an important role in the function of the device.
If you’re looking to purchase a new stethoscope, our buyer’s guide covers the best stethoscopes available on the market to help you make an informed decision for your specific need.
Written by:
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.
References
- “Anatomy of a Stethoscope.” 3M Littman Stethoscope, 2023.
- “Proper Use of the Stethoscope.” National Center for Biotechnology Information, 2013.
- “A New Stethoscope Design with Unique Characteristics and Development in Medical Device.” PubMed Central (PMC), 1 Mar. 2018.