Fit the earpieces, warm the chestpiece, and listen in a quiet room across four valve landmarks plus Erb’s point, alternating the bell and diaphragm to catch both low- and high-frequency vibrations. You then time what you hear against S1 and S2 so you can place each murmur in systole or diastole, grade its intensity, and document its shape, location, radiation, and pitch. With repeated practice on normal hearts, abnormal sounds stand out quickly, and your findings become a useful baseline for the next clinician.
This walkthrough walks through the practical skills every medical student or new clinician needs at the bedside, covering stethoscope fit, valve landmarks, and the stepwise method for timing, grading, and describing murmurs with confidence.
Getting the Stethoscope Ready Before You Listen
Most beginners blame their ears when a sound doesn’t appear, but the problem usually lives in the tool. A poorly fitted stethoscope filters out the very frequencies that distinguish a murmur from background noise, so setup is the first skill to master.
Earpieces, Tubing, and Patient Comfort
Your earpieces should angle forward, lining up with the natural direction of your ear canal. Misaligned tips leak ambient sound and force your brain to strain, which dulls the subtle vibrations you’re hunting for. Tubing shorter than about 12 inches tends to preserve high-frequency detail, while longer tubing softens it; switch to the shorter tubing for cardiac work whenever you have the choice.
A cold diaphragm can make a patient flinch or shift their breathing, which alters the sounds you’re trying to capture. Rub the chestpiece between your palms for a few seconds, or tuck it under your arm briefly, so the first contact feels neutral and the patient stays still.
Bell Versus Diaphragm
The bell picks up low-frequency sounds, like the rumble of mitral stenosis or a soft S3, and only works when placed lightly on the skin. The diaphragm picks up high-frequency sounds, like the snap of an opening snap or the click of a prosthetic valve, and needs firm pressure to filter out the low rumble. Switching between them at each landmark is what separates a useful exam from a guess.
Tip: A high-quality acoustic stethoscope, such as the 3M Littmann Classic III, has both heads on a single chestpiece. Rotate the head by holding the stem, not the tubing, to avoid twisting the Y-junction over time.
The Anatomy Behind the Sounds You Hear
Every normal heartbeat produces two sharp sounds through the stethoscope: S1 and S2. Those sounds anchor everything else, because murmurs can only be timed against them once S1 and S2 are clearly identified.
S1, S2, and the Silent Spaces
S1 marks closure of the mitral and tricuspid valves, the “lub” of the classic “lub-dub,” and signals the start of systole. S2 marks closure of the aortic and pulmonary valves, the “dub,” and signals the start of diastole. The brief silence between S1 and S2 is systole, when the ventricles are squeezing blood out. The longer silence between S2 and the next S1 is diastole, when the ventricles refill. Spend a few minutes just locking that rhythm into muscle memory before chasing anything else.
Where Murmurs Come From
Murmurs arise when turbulent blood flow creates vibrations the stethoscope can amplify. Anything that speeds blood up, narrows a passage, or allows backflow through a valve can produce one. That’s why a fever, anemia, pregnancy, or a tight stenotic valve can all create audible flow noise, even when the heart itself is structurally sound.
Positioning the Patient and Finding Your Landmarks
Environment and posture change what the heart sounds like, so your setup matters as much as your ear. Listening to someone hunched on an exam table in a noisy hallway produces a different exam than listening to the same person settled, breathing quietly, in a still room.
Setting Up the Room
Pick the quietest space you can find, close the door, and ask the patient to breathe normally through their nose. Listen with the patient sitting up, leaning slightly forward with arms relaxed. That posture brings the heart closer to the chest wall and exposes the left sternal border and the aortic area. Then ask the patient to roll into the left lateral decubitus position, lying on their left side, which brings the cardiac apex forward and makes the low-pitched rumble of mitral stenosis far easier to catch.
The Four Valve Areas and Erb’s Point
Cardiac auscultation uses a small map of named listening spots, each tied to one of the four heart valves. The aortic area sits at the right second intercostal space, right next to the sternum. The pulmonic area sits at the left second intercostal space, also at the sternal border. The tricuspid area lives at the left lower sternal border, around the fourth or fifth intercostal space. The mitral area sits at the cardiac apex, near the point of maximal impulse, usually around the fifth intercostal space in the midclavicular line.
Erb’s point, at the left third intercostal space, sits between the aortic and pulmonic areas and is worth a deliberate pause. Sounds from the aortic valve in particular often radiate to this spot.
| Landmark | Location | Best For |
|---|---|---|
| Aortic area | Right 2nd intercostal space, sternal border | Aortic stenosis, aortic regurgitation |
| Pulmonic area | Left 2nd intercostal space, sternal border | Pulmonic flow murmurs, pulmonary hypertension |
| Erb’s point | Left 3rd intercostal space, sternal border | Aortic regurgitation radiations |
| Tricuspid area | Left lower sternal border, 4th-5th ICS | Tricuspid regurgitation, VSDs |
| Mitral area (apex) | 5th intercostal space, midclavicular line | Mitral stenosis, mitral regurgitation |
Moving Systematically Across the Four Valve Areas
Random listening misses murmurs, while a disciplined sweep across the precordium makes abnormal sounds stand out. Your brain learns what “normal” sounds like at each spot before anything pathological enters the picture, which is why order matters as much as ear.
The Inching Technique
Start at the aortic area, listen for a full cardiac cycle, then move the chestpiece a centimeter at a time across the precordium in a slow Z or zigzag pattern. Inch toward the apex, then sweep back along the left sternal border. At each stop, identify S1 and S2, decide which silence is systole, and only then judge whether a murmur is present. The “inch” part of the technique matters because some murmurs are loud only in one small zone, especially aortic regurgitation, which can vanish the moment you slide an inch off Erb’s point.
Switching Heads and Repeating in Left Lateral Decubitus
At every landmark, alternate between the bell (light pressure) and the diaphragm (firm pressure). Low-frequency diastolic rumbles, such as the opening snap and diastolic rumble of mitral stenosis, only appear with the bell. High-frequency clicks and snaps, including pericardial friction rubs, need the diaphragm. Once the seated sweep is done, roll the patient into left lateral decubitus and re-listen at the apex with the bell. That single maneuver can reveal a mitral stenosis murmur that’s completely silent with the patient sitting up.
Patient position changes which sounds reach your ears, and Erbs point makes that principle clinically useful.
Warning: Murmurs grade 3 or higher usually produce a palpable vibration called a thrill. If you feel a “buzz” under your fingertips at a landmark, document it; a thrill almost always points to a clinically important lesion and warrants further evaluation by a cardiologist.
Recognizing Murmur Timing, Shape, and Radiation
Once you’ve learned where to listen, the next question is what to listen for. Murmurs are described by five properties: timing, shape, location, radiation, and intensity. Each one narrows the list of possible causes and points toward the underlying valve lesion.
Timing and Shape
Systolic murmurs fall between S1 and S2. Diastolic murmurs fall between S2 and the next S1, which makes them easier to miss because diastole is longer and quieter. Crescendo-decrescendo murmurs (swelling then fading) suggest ejection flow, such as aortic stenosis, while plateau or holosystolic murmurs (constant intensity through systole) suggest regurgitation, such as mitral regurgitation or a ventricular septal defect.
Radiation, Intensity, and Pitch
Radiation gives strong clues. A murmur that travels to the carotids strongly suggests aortic stenosis. One that travels to the axilla points toward mitral regurgitation. Intensity is graded on a 1–6 scale, with grade 1 barely audible in a quiet room and grade 6 audible with the stethoscope off the chest. Pitch and quality descriptors, like harsh, blowing, musical, or rumbling, help separate valve lesions that share timing but differ in texture.
| Feature | What to Listen For | Common Associations |
|---|---|---|
| Timing | Systolic vs. diastolic | Diastolic murmurs rarely benign |
| Shape | Crescendo-decrescendo, plateau, holosystolic | Shape suggests ejection vs. regurgitant flow |
| Radiation | Carotids vs. axilla vs. back | Localizes the valve involved |
| Intensity | Grade 1-6 | Grade 3+ warrants closer evaluation |
| Pitch/quality | Harsh, blowing, musical, rumbling | Matches specific valve lesions |
Separating Innocent Murmurs From Concerning Findings
Not every murmur signals heart disease. Many healthy people, especially children, pregnant people, and athletes, have audible flow murmurs that require no follow-up. Your task during auscultation is to tell those apart from findings that should be flagged to a clinician.
Features of Innocent Murmurs
Short, soft, and systolic, innocent murmurs are heard best at the left lower sternal border or pulmonic area. They tend to soften or disappear when the patient stands or holds their breath, and they never produce a thrill. A Still’s murmur in a child or a soft pulmonary flow murmur in a young adult fits this pattern.
Red Flags Worth Documenting
Pathological murmurs more often extend through systole, occur in diastole, or radiate away from their origin. Red flags include a palpable thrill, a diastolic timing, a grade above 3, or any change from a prior exam. Documenting using timing, shape, location, radiation, intensity, and pitch gives the next clinician a comparable baseline. For example: “Grade 3/6 holosystolic murmur at the apex, radiating to the axilla” tells a cardiologist far more than a vague note like “murmur heard.” When findings raise concern, follow the recommendations of an appropriate specialist doctor, such as a cardiologist, for further evaluation; for persistent symptoms like chest pain, shortness of breath, or fainting, that evaluation should not be delayed.
Building a Baseline Through Practice
Treating repeated practice on normal hearts as the baseline that makes abnormal sounds recognizable is the single biggest skill-builder. Listen to friends, family, or willing colleagues who have no cardiac history. After a few dozen normal exams, the texture of an unexpected diastolic rumble or a high-pitched blowing sound becomes impossible to miss. A stethoscope is a learned instrument, and the heart, like any instrument, rewards patience.
Key Takeaways
A reliable cardiac exam starts with a well-fitted stethoscope, short tubing, and a quiet room. S1 and S2 anchor every interpretation; the silence between them tells you where systole and diastole live, and that timing is the single most useful clue when a murmur appears. Inch methodically across the four valve areas and Erb’s point, switch between bell and diaphragm at every stop, and document findings using timing, shape, location, radiation, intensity, and pitch. If a thrill appears, the murmur is diastolic, or its grade exceeds 3, refer the patient for specialist evaluation.
FAQ
Where do you place a stethoscope to hear a heart murmur?
Place the chestpiece at the four valve areas in order: right second intercostal space (aortic), left second intercostal space (pulmonic), left lower sternal border (tricuspid), and the cardiac apex (mitral). Pause at Erb’s point between the aortic and pulmonic spots, and repeat the apex with the patient rolled into left lateral decubitus for mitral detail.
What do normal heart sounds S1 and S2 sound like through a stethoscope?
S1 and S2 are sharp, quick valve-closure sounds, often described as “lub-dub.” S1, the first sound, is slightly longer and louder; S2 is sharper and higher-pitched. They are best heard with the diaphragm at the base of the heart for S2 and at the apex for S1.
How can you tell the difference between a systolic and diastolic murmur?
Identify S1 and S2 first. A murmur between S1 and S2 is systolic; one between S2 and the next S1 is diastolic. Diastolic murmurs are longer, quieter, and easier to miss, but they are rarely benign.
Which stethoscope head is used for low-pitched heart sounds and murmurs?
Use the bell, placed lightly on the skin. Low-pitched sounds like mitral stenosis rumbles, S3, and S4 gallops need the bell; firm pressure switches the same head into diaphragm mode and filters out the low frequencies.
How do you properly position a patient for cardiac auscultation?
Start with the patient sitting up, leaning slightly forward with arms relaxed, in a quiet room. Listen at all four valve areas plus Erb’s point, then roll the patient into left lateral decubitus and re-listen at the apex with the bell to expose mitral findings.
What causes a heart murmur that can be detected with a stethoscope?
Turbulent blood flow through the heart valves or great vessels. Causes include narrowed valves (stenosis), leaky valves (regurgitation), septal defects, and high-flow states such as fever, anemia, pregnancy, or hyperthyroidism.
