Mastering Auscultation: What Is the Correct Way to Use a Stethoscope?

October 2, 2025 •

4 min read

According to a study published by the National Institutes of Health, one in three stethoscopes may be contaminated with potentially fatal bacteria like MRSA. Beyond cleaning, understanding what is the correct way to use a stethoscope? is fundamental to accurate patient assessment and preventing infection.

Quick Summary

This article outlines the proper procedure for using a stethoscope, from correctly wearing the earpieces and selecting the chest piece to mastering auscultation techniques for heart and lung sounds. It also covers essential maintenance and hygiene practices for the device. The guide is useful for new medical students and seasoned professionals seeking a refresher on proper technique.

Key Points

Proper Earpiece Direction: The eartips should point forward, towards your nose, to align with your ear canals for an optimal acoustic seal.
Diaphragm for High-Pitched Sounds: Use the larger, flat diaphragm side of the chestpiece with firm pressure to hear higher-frequency sounds like breath and bowel sounds.
Bell for Low-Pitched Sounds: Use the smaller, cup-shaped bell side with light pressure to listen for low-frequency sounds such as heart murmurs.
Direct Skin Contact is Key: Always place the chestpiece directly on the patient's bare skin, as clothing can muffle or distort sounds.
Maintain Hygiene Between Patients: Disinfect all patient-contacting surfaces of the stethoscope, especially the chestpiece and eartips, with 70% isopropyl alcohol after each patient interaction to prevent cross-contamination.
Adjust Headset for Comfort: Ensure the binaural tension is not too tight or too loose, adjusting it by squeezing or pulling the metal tubes as needed for a comfortable, snug fit.

Understanding the Parts of Your Stethoscope

Before learning the technique, it is essential to understand the components of a modern stethoscope and their functions. A standard stethoscope comprises a headset with earpieces, flexible tubing, and a chestpiece at the end. The chestpiece is the most critical element, as it captures the body's sounds.

The Headset and Earpieces

The headset consists of the metal binaurals and the soft eartips. These tips must form a tight, comfortable seal to block outside noise and ensure clear sound transmission. To achieve this, the eartips should be angled forward, pointing towards your nose when inserted into your ears. Many models include interchangeable eartips of different sizes to help you find the best fit.

The Versatile Chestpiece: Diaphragm and Bell

The chestpiece of a dual-head stethoscope features two sides.

Diaphragm: This is the larger, flat side, which is best for detecting high-pitched sounds. It works by vibrating in response to sound waves, creating acoustic pressure that travels through the tubing.
Bell: This smaller, concave side is used for low-pitched sounds, such as certain heart murmurs and bruits. It functions by collecting low-frequency sound vibrations directly from the skin.

To switch between the diaphragm and the bell, you must rotate the stem of the chestpiece until it clicks into place. This action closes the sound path to one side while opening it to the other. Some modern stethoscopes feature a tunable single-head chestpiece, which detects different frequencies by simply adjusting the pressure you apply.

How to Wear and Adjust Your Stethoscope

Proper fit is crucial for optimal acoustic performance and user comfort. Follow these steps to ensure your stethoscope is ready for use:

Check Earpiece Alignment: Hold the headset with the earpieces pointing forward, away from you. Insert the eartips gently but firmly into your ears.
Adjust Headset Tension: The fit should be snug enough to block ambient noise but not so tight that it's uncomfortable. Gently squeeze the binaurals closer together to increase tension or pull them apart to decrease it.
Ensure a Good Seal: A proper acoustic seal is vital for hearing. Test the seal by tapping the diaphragm while wearing the earpieces; the sound should be loud and clear. If not, adjust the tension or check for clogs.

The Correct Auscultation Technique

Effective auscultation requires practice, a quiet environment, and proper patient positioning. Placing the chestpiece directly on the patient's bare skin is essential, as clothing can obscure or muffle sounds. Always warm the chestpiece with your hands before applying it to the patient's skin.

Listening to Heart Sounds

To listen to heart sounds, follow these steps:

Patient Position: Have the patient sit up or lie down. For clearer heart sounds, ask them to lean forward or roll onto their left side.
Use the Diaphragm: Use the diaphragm for higher-pitched sounds, like the standard 'lub-dub' of the heart.
Use the Bell: Use the bell with light pressure to listen for lower-pitched murmurs.
Auscultation Points: Systematically move the chestpiece to the five key areas on the chest where heart valve sounds are best heard, comparing left and right sides where applicable.

Listening to Lung Sounds

Listening to lung sounds helps assess a patient's respiratory status.

Patient Position: Ask the patient to sit upright. For better access to posterior lung fields, have them lean forward with their arms crossed over their lap.
Use the Diaphragm: Use the diaphragm for high-pitched breath sounds.
Auscultation Pattern: Start by listening from the top of the lungs, comparing the left and right sides as you work your way down the chest and back. Ask the patient to take deep breaths through their mouth at each site to help you hear clearly.

Measuring Blood Pressure

Wrap the Cuff: Place the blood pressure cuff snugly around the patient's arm, just above the elbow.
Position the Stethoscope: Find the brachial artery in the antecubital fossa by feeling for a pulse. Place the stethoscope's diaphragm directly over the artery, just below the cuff.
Inflate and Listen: Inflate the cuff to approximately 180 mmHg or 30 mmHg above the estimated systolic pressure. Slowly release the air and listen for the first sound (systolic pressure) and the last sound (diastolic pressure).

Diaphragm vs. Bell: A Quick Comparison


Feature	Diaphragm	Bell
Function	Filters out low frequencies to focus on high-pitched sounds.	Amplifies low-frequency sounds.
Sounds Heard	Lung sounds, normal heart sounds, bowel sounds.	Heart murmurs, some vascular sounds (bruits).
Application	Firm pressure on the skin.	Light pressure on the skin.
Auscultation Area	Better for larger areas like the chest and back.	More effective for small areas or bony landmarks.
Acoustic Effect	Better for clearer, higher-pitched sounds.	Better for picking up subtle, lower-pitched sounds.

Stethoscope Hygiene and Maintenance

Maintaining a clean stethoscope is critical for infection control.

Disinfect Regularly: Clean all patient-contacting surfaces with a 70% isopropyl alcohol wipe between each patient assessment.
Deep Clean Periodically: For a deeper clean, remove the eartips and tunable diaphragms. Wipe parts with alcohol or wash with mild soapy water, then dry thoroughly before reassembly.
Avoid Submerging: Never immerse your stethoscope in any liquid, as this can damage the components.
Proper Storage: Store your stethoscope in a case to protect it from extreme temperatures and sunlight, which can degrade the tubing. Avoid wearing it draped around your neck for prolonged periods, as skin oils can cause hardening.

Conclusion: Mastering the Art of Auscultation

The stethoscope is an indispensable tool in healthcare, and understanding what is the correct way to use a stethoscope? is a fundamental skill for medical professionals. By mastering the proper technique for wearing, adjusting, and manipulating the device, you can enhance your diagnostic accuracy and improve patient care. Regular practice and proper hygiene are key to becoming proficient in auscultation and maintaining a reliable, functional piece of equipment for years to come. For more detailed clinical guidance, resources like Practical Clinical Skills offer a wide range of educational materials on using a stethoscope effectively.

Frequently Asked Questions

To check which side is active, gently tap on the diaphragm while wearing the earpieces. If you hear the tapping sound, that side is active. On many stethoscopes, an indicator dot or a slight bend in the stem shows which side is currently open.

The bell side is used for auscultating low-pitched sounds, such as heart murmurs and some types of vascular sounds (bruits). For best results, it should be applied to the skin with light pressure.

For optimal lung auscultation, ask the patient to sit upright. Having them lean forward with their arms crossed over their lap can help expose the posterior lung fields more effectively.

While convenient, wearing a stethoscope around your neck for prolonged periods can degrade the tubing due to skin oils and stretching. It's better to store it in a protective case when not in use.

Several factors could cause this. First, check that the earpieces are pointed forward, aligned with your ear canals. If you have a dual-head model, ensure the active side is properly engaged by rotating the stem until it clicks. Lastly, check for blockages like earwax or debris.

The tubing can be cleaned with a 70% isopropyl alcohol wipe or mild soapy water. Wipe it down, but avoid letting excess water drip into the metal parts. It is essential not to use hand sanitizer or harsh chemicals, which can damage the tubing over time.

Yes, the diaphragm is commonly used for measuring blood pressure. Place it over the brachial artery below the cuff to listen for Korotkoff sounds as you release the pressure.