My first week of nursing school, the instructor drew five dots on a plastic torso and told us to memorize them. "Aortic, pulmonic, Erb's point, tricuspid, mitral." She rattled them off like grocery items. "All Patients Take Meds," she said, giving us the mnemonic. I dutifully wrote it down, placed my stethoscope on each spot during lab, and passed the practical exam without truly understanding why those positions mattered.
It wasn't until years later, working night shift in the pediatric cardiac ICU, that I finally got it. A two-year-old with truncus arteriosus had just come back from the OR. The fellow asked me what I heard at the left lower sternal border. I placed my stethoscope there and heard a harsh systolic murmur that wasn't present at the apex. "Why does it sound different here?" I asked. He pulled out a pen and sketched the heart's anatomy on a paper towel, showing me how sound radiates from each valve to specific chest wall locations based on blood flow direction and the heart's position in the chest.
That paper towel explanation taught me more than a semester of memorizing dots on a plastic mannequin. So let's talk about heart sound positions the way someone should have explained them to me from the start.
Why Position Matters (And It's Not What You Think)
Here's what nobody tells you: you're not actually listening to the valves themselves. You can't. They're buried too deep in the chest. What you're hearing is the sound those valves make as blood accelerates through cardiac structures and the chest wall to reach your stethoscope. Each valve's sound radiates in the direction of blood flow. The aortic valve sends blood up toward the right shoulder, so you hear it best at the right upper sternal border. The mitral valve sits at an angle pointing toward the left axilla, so its sound projects there.
The heart isn't positioned in your chest the way those tidy anatomical drawings suggest. It's rotated. The right ventricle makes up most of the anterior surface. The left ventricle is posterior and leftward. This rotation is why the "best" listening spots don't align with the valves' anatomical positions. We're following sound waves, not a two-dimensional anatomy.
This matters clinically because pathology changes how sound radiates. A severe aortic stenosis murmur might radiate to the carotids because you're hearing turbulent flow shooting up into those vessels. Mitral regurgitation radiates to the axilla because blood is jetting backward through an incompetent valve in that direction. Understanding the "why" behind positioning helps you predict what you'll hear and where you'll hear it.
The Aortic Area: Right Second Intercostal Space
Feel for your sternal notch at the base of your neck. Drop your fingers down to the first bony ridge you hit. That's the sternal angle, where the second rib attaches. Follow that rib out to the right side. This is your aortic area, and it's where you'll hear the aortic valve close (the second heart sound, S2) at its loudest.
The aortic valve sits between the left ventricle and the aorta. When it closes, it prevents blood from flowing backward into the ventricle during diastole. That closure creates S2, and because blood is flowing upward and to the right toward the great vessels, the sound projects to the right upper chest.
What you're listening for here: S2 should be crisp and singular at this location. If you hear a split S2 (two distinct components), pay attention. In young people and athletes, you might hear physiologic splitting that widens with inspiration. That's normal. But fixed splitting (which doesn't change with breathing) or paradoxical splitting (which widens with expiration) points to serious pathology. Fixed splitting suggests an atrial septal defect, in which the right ventricle is chronically volume-overloaded and takes longer to empty. Paradoxical splitting can indicate left bundle branch block or severe aortic stenosis.
Aortic stenosis creates a harsh, crescendo-decrescendo systolic murmur that you'll hear best at this position. The murmur radiates to the carotids because turbulent flow through the narrowed valve continues up into those vessels. I learned to check carotid radiation on every elderly patient with a systolic murmur at the right upper sternal border. If I could hear it in the neck, the stenosis was usually severe enough to matter.
Here's something I wish someone had told me earlier: the intensity of an aortic stenosis murmur doesn't always correlate with severity. As stenosis worsens and cardiac output drops, the murmur can actually become softer because there's less flow across the valve. Always correlate what you hear with the clinical picture.
The Pulmonic Area: Left Second Intercostal Space
Cross over to the left side at the same level, left second intercostal space at the sternal border. This is the pulmonic area. The pulmonic valve sits between the right ventricle and the pulmonary artery, and its closure contributes to S2. This might seem counterintuitive, as the pulmonic valve is a right-sided heart structure; it is important to remember the direction in which the sound best radiates.
In healthy adults, you hear both aortic and pulmonic components of S2 at this location, with the aortic component slightly louder and earlier. The pulmonic component is usually softer because pressures in the pulmonary system are much lower than in the systemic circulation.
What you're listening for here: This is the best spot to appreciate physiologic splitting of S2. During inspiration, negative intrathoracic pressure increases venous return to the right heart. That extra volume takes the right ventricle slightly longer to eject, delaying pulmonic valve closure. You hear this as S2 splitting into two components on inspiration that come back together on expiration. It's subtle, but once you train your ear to catch it, you'll hear it on almost every young patient.
A loud P2 (pulmonic component of S2) at this location suggests pulmonary hypertension. When pressures in the pulmonary system are elevated, the pulmonic valve slams shut harder, creating a louder sound. In my cardiac ICU days, I listened for this on every patient with a history of pulmonary hypertension or chronic lung disease. A loud, sometimes palpable P2 told me their pressures were poorly controlled.
Pulmonic stenosis creates a systolic ejection murmur at this location. You'll hear the murmur, and often an ejection click right after S1. That click is the stenotic valve suddenly snapping open against increased pressure. The more severe the stenosis, the earlier the click occurs after S1.
Erb's Point: Left Third Intercostal Space
Drop down one interspace from the pulmonic area, staying at the left sternal border. This is Erb's point, sitting at the left third intercostal space. It's named after Wilhelm Erb, a German neurologist, though why a neurologist gets credit for a cardiac auscultation point is beyond me.
Erb's point is clinically useful because you can hear both aortic and pulmonic sounds reasonably well here. It's a compromise position that lets you compare the two semilunar valves side by side.
What you're listening for here: This is my go-to spot for listening to diastolic murmurs. Aortic regurgitation creates a high-pitched, blowing diastolic murmur that's often easier to hear at Erb's point than at the traditional aortic area. The regurgitant jet of blood flowing backward through an incompetent aortic valve projects down the left sternal border, making it audible here.
The technique matters for aortic regurgitation. Sit the patient up, have them lean forward, and have them exhale completely and hold it. This position brings the heart closer to the anterior chest wall and makes that soft diastolic murmur easier to catch. I've heard attendings describe listening for aortic regurgitation as "listening for the sound of wind through trees." It's soft, high-pitched, and easy to miss if you're not deliberately hunting for it.
Pulmonic regurgitation can also be heard at Erb's point, though it's less common. It creates a softer, lower-pitched diastolic murmur because pulmonary pressures are lower than aortic pressures.
The Tricuspid Area: Left Fourth or Fifth Intercostal Space
Continue down the left sternal border to the fourth or fifth intercostal space. This is the tricuspid area, though calling it that is slightly misleading. You're not directly over the tricuspid valve. You're over the right ventricle, which makes up most of the anterior heart surface, and you're picking up sounds from the tricuspid valve as they radiate through the right ventricular wall.
The tricuspid valve sits between the right atrium and right ventricle. When it closes with ventricular contraction, it contributes to S1, though the mitral component is usually louder and dominates what you hear.
What you're listening for here: Right-sided heart sounds increase with inspiration. When you breathe in, you increase venous return to the right heart, which increases right-sided flow and makes tricuspid sounds louder. This is the opposite of left-sided sounds, which often decrease slightly with inspiration as the left heart receives less return.
Use this principle diagnostically. If you hear a murmur at the left lower sternal border and you're not sure if it's tricuspid or mitral, have the patient take a deep breath. If the murmur gets louder with inspiration, it's right-sided (tricuspid). If it stays the same or gets softer, it's left-sided (mitral).
Tricuspid regurgitation creates a holosystolic (pansystolic) murmur at this location. The murmur is usually softer than mitral regurgitation because right-sided pressures are lower. In severe cases, you might see prominent v-waves in the jugular venous pulsation that correspond with the regurgitant flow.
I spent enough time with patients on ECMO and patients with pulmonary hypertension to recognize severe tricuspid regurgitation by sound alone. The murmur would fill systole, sometimes accompanied by a thrill you could feel with your hand flat on the chest. These sometimes have enlarged livers from chronic right heart failure and peripheral edema that seemed impossible to diurese.
The Mitral Area: Fifth Intercostal Space, Midclavicular Line
The mitral area is the farthest left and lowest of the standard positions. Find the fifth intercostal space (level with the bottom of the sternum) and follow it out to the midclavicular line. In many patients, this is close to where you can see or feel the point of maximal impulse (PMI), the spot where the left ventricle taps against the chest wall with each beat.
The mitral valve sits between the left atrium and left ventricle. Its closure creates the first heart sound (S1) and is usually the loudest component of S1 since left-sided pressures are higher than right-sided pressures.
What you're listening for here: S1 should be loudest at the apex of the heart. If S2 is louder than S1 at this location, something's wrong. Either you're too far to the right (toward the base of the heart) or there's pathology affecting S1 intensity.
The mitral area is where you'll hear S3 and S4 gallops if they're present. Both are low-frequency sounds best heard with the bell or with light pressure if using a tunable diaphragm. Have the patient roll onto their left side (left lateral decubitus position) to bring the heart's apex closer to the chest wall. This positioning makes subtle gallops much easier to detect.
S3 occurs in early diastole and sounds like "lub-dub-dup" (Kentucky). In young people and athletes, it's usually benign. In older adults or people with known heart disease, it suggests volume overload and reduced left ventricular compliance. I learned to listen for S3 on every heart failure admission because its presence or absence helped guide diuretic management.
S4 occurs in late diastole, just before S1, and sounds like "ta-lub-dub" (Tennessee). It indicates a stiff, non-compliant ventricle that requires forceful atrial contraction to fill. You'll hear S4 in patients with long-standing hypertension, hypertrophic cardiomyopathy, or acute myocardial infarction.
Mitral regurgitation creates a holosystolic murmur that radiates to the axilla. The regurgitant jet of blood flowing backward through the incompetent valve shoots toward the left axilla, which is why you follow the sound in that direction. Severe mitral regurgitation can be audible in the patient's back, under the left scapula.
Mitral stenosis creates a low-pitched, rumbling diastolic murmur preceded by an opening snap. The opening snap is the stenotic valve suddenly popping open against resistance. As stenosis worsens, the opening snap moves closer to S2. The murmur itself is best heard with the patient in the left lateral decubitus position, using the bell of your stethoscope with very light pressure.
Putting It Together
Learning these positions takes time and repetition. When I started in the cardiac ICU, I listened to every patient systematically, moving through all five positions even when I didn't expect to hear anything abnormal. That deliberate practice taught me what normal sounds like, which made abnormal sounds obvious when I encountered them.
A few practical tips I've picked up: always listen in a quiet room with the patient's gown removed. Clothing creates an artifact that obscures subtle findings. Use the diaphragm for high-pitched sounds (S1, S2, most murmurs, rubs) and the bell or light pressure on a tunable diaphragm for low-pitched sounds (S3, S4, mitral stenosis). Position matters for certain findings, so don't skip having the patient sit up and lean forward for aortic regurgitation or roll into left lateral decubitus for mitral stenosis and gallops.
Compare what you hear with the clinical context. A murmur that sounds like severe aortic stenosis should correlate with symptoms like exertional dyspnea, angina, or syncope. If the patient is completely asymptomatic and running marathons, reconsider your interpretation.
Your stethoscope matters more for cardiac auscultation than almost any other application. At Apex Stethoscopes, we design our acoustic system to capture the full range of heart sounds, from the high-frequency components of S1 and S2 to the low rumbles of diastolic murmurs and gallops. The tunable diaphragm gives you the flexibility to switch between frequency ranges without lifting your stethoscope off the chest, which helps when you're comparing findings across positions.
What matters most is that you practice systematically, learn what normal sounds like in different age groups and body types, and stay curious when you hear something unusual. The heart has a lot to tell you if you know where and how to listen.
We offer eight color options because medicine isn't just about pure function. Your stethoscope becomes part of your professional identity. When you wear something around your neck for twelve-hour shifts, it should reflect who you are as a healthcare provider while maintaining absolute clinical performance.
