Using a stethoscope starts with putting it on correctly: the earpieces should point forward, toward your nose, as you insert them. This matches the natural angle of your ear canals and creates an airtight seal that makes the difference between hearing clear body sounds and hearing almost nothing. From there, technique depends on what you’re listening for, whether that’s a heartbeat, breath sounds, or blood pressure.
Parts You Need to Know
A standard stethoscope has two sides on its chest piece. The larger, flat side is the diaphragm, which picks up high-frequency sounds like normal heartbeats and breath sounds. The smaller, cupped side is the bell, which is better for low-frequency sounds like certain heart murmurs. Some newer models use a “tunable” diaphragm that switches between high and low frequencies based on how hard you press, but the principle is the same: light pressure favors low-pitched sounds, firm pressure favors high-pitched ones.
The tubing connects the chest piece to the headset. Shorter tubing generally transmits sound better, though most stethoscopes come in a standard length that balances sound quality with practical reach. The headset includes the metal earpieces (binaurals) and soft ear tips. If the ear tips don’t seal snugly in your ears, outside noise leaks in and internal sounds get lost. Most stethoscopes come with multiple ear tip sizes for this reason.
Getting the Fit Right
Hold the stethoscope in front of you and notice that the earpieces angle slightly forward. This isn’t a manufacturing quirk. Your ear canals point toward the front of your head, so the earpieces need to follow that same direction. If you put them in backward (angled toward the back of your head), you’ll hear very little and assume the stethoscope is broken.
Once the ear tips are seated, gently tug on them to check the seal. You should notice a drop in ambient noise. If the fit feels loose or uncomfortable, try swapping to the other ear tip size included with your stethoscope. A proper acoustic seal matters more than an expensive model.
Listening to the Heart
Heart sounds are best heard at five specific spots on the chest, each corresponding to a different valve. You don’t need to memorize the anatomy to use them. Just know the landmarks:
- Aortic area: between the second and third ribs on the right side of the breastbone
- Pulmonic area: the same spot, but on the left side of the breastbone
- Erb’s point: left side of the chest, between the third and fourth ribs
- Tricuspid area: between the fourth and fifth ribs, near the lower left edge of the breastbone
- Mitral area: at the bottom tip of the heart, roughly below the left nipple
Start with the diaphragm side pressed firmly against the skin. You’re listening for the classic “lub-dub” pattern. The first sound (“lub”) is the closing of the valves between the upper and lower chambers. The second sound (“dub”) is the closing of the valves leading to the lungs and the rest of the body. Move through all five points in order, spending several heartbeats at each one. If you want to check for low-pitched murmurs, flip to the bell side (or lighten your pressure on a tunable diaphragm) and revisit the same spots.
Place the chest piece directly on skin whenever possible. Listening through clothing, especially thick fabric, muffles sounds significantly and can make you miss important details.
Listening to the Lungs
The best position for lung sounds is sitting upright. If that’s not possible, lying on one side and then the other works as a substitute. Use the diaphragm side and press firmly enough to make good contact.
The key technique here is comparing side to side. Listen to the upper right lung, then the upper left. Move down to the middle right, then middle left. Continue to the lower fields. This “ladder pattern” lets you compare symmetrical areas of the lungs directly, so you can catch differences between the two sides. If you listened all the way down one side first, you’d have to remember what the upper right sounded like by the time you reached the upper left.
Ask the person you’re listening to (or remind yourself, if you’re practicing) to breathe deeply through the mouth. Nose breathing is quieter and can make subtle sounds harder to detect. Normal breath sounds are soft and rustling on the way in, and even quieter on the way out. Crackling, wheezing, or absent sounds on one side are the kinds of things this technique is designed to catch.
For a thorough exam, listen to at least six spots on the back (three on each side) and four on the front. The back gives you better access to the lower lobes of the lungs, where fluid and infection tend to settle first.
Taking Blood Pressure
Blood pressure measurement is one of the most common reasons people use a stethoscope at home. Wrap the cuff around the upper arm, about an inch above the elbow crease, with the tubing running down the inner arm. Place the stethoscope’s diaphragm (or bell, which some clinicians prefer for its sensitivity to low-frequency sounds) over the brachial artery, just inside the elbow.
Inflate the cuff to about 180 mmHg, or roughly 30 points above where you expect the systolic number to be. Then slowly release the pressure, about 2 to 3 mmHg per second. You’re listening for a series of sounds called Korotkoff sounds, which progress through five phases:
- Phase I: clear, rhythmic tapping sounds appear. The pressure reading at this moment is your systolic blood pressure (the top number).
- Phase II: the tapping softens and gains a swishing quality.
- Phase III: the tapping returns, louder and sharper than before.
- Phase IV: the sounds suddenly become muffled and soft.
- Phase V: silence. The reading at this moment is your diastolic blood pressure (the bottom number).
The most common mistake is deflating the cuff too quickly, which causes you to miss Phase I or overshoot Phase V. Patience with the valve makes a bigger difference than the quality of your equipment.
Using a Stethoscope on Children
Pediatric stethoscopes have a noticeably smaller chest piece, typically around 2.9 cm across compared to 4.3 or 4.4 cm on adult models. This isn’t just about fitting on a smaller chest. A chest piece that’s too large for the body it’s placed on can’t form a good seal against the skin, which lets sound escape. For infants and small children, the pediatric size makes proper contact possible.
The listening technique is the same as for adults, but you’ll find the landmarks closer together on a small chest. Heart sounds are often louder and faster in children (a resting heart rate of 100 to 120 beats per minute is normal for a toddler), which can sound alarming if you’re used to listening to adults. Breath sounds also transmit more easily through a thinner chest wall, so you may hear sounds from the opposite lung bleeding through, which is normal.
Cleaning Your Stethoscope
Stethoscopes pick up bacteria from every surface they touch. A wipe with 70% isopropyl alcohol after each use is the most effective and practical cleaning method. It significantly reduces bacterial contamination on both the diaphragm face and the rim, which is the area most often missed during cleaning. Standard alcohol-based hand sanitizer also works in a pinch, though a dedicated alcohol wipe covers the surface more thoroughly.
Pay attention to the rim and crevices of the chest piece, not just the flat diaphragm surface. Bacteria accumulate in the edges where the diaphragm meets the housing. The ear tips should also be wiped down regularly and replaced when they lose their shape or flexibility, since a degraded ear tip compromises both hygiene and sound quality.
Store your stethoscope away from extreme heat and direct sunlight. The tubing on most models is made of PVC or similar materials that stiffen and crack with prolonged heat exposure, which degrades acoustic performance over time. Draping it around your neck for hours also accelerates tubing wear from skin oils and sweat. A case or hook is better for the stethoscope’s longevity.