The apex of the heart is the pointed, lower tip of the heart, formed by the left ventricle. In adults, it sits behind the left 5th intercostal space (the gap between the 5th and 6th ribs), roughly 9 cm to the left of the center of your chest. That distance is about the width of your palm. Because the heart is tilted in the chest, the apex points downward and to the left, which is why you feel your heartbeat most strongly on the left side.
Which Part of the Heart Forms the Apex
The apex is made up of the inferolateral part of the left ventricle, the chamber responsible for pumping oxygen-rich blood out to the rest of the body. This is the thickest, most muscular chamber, and its strong contractions are what create the palpable “thump” you can feel through the chest wall. The shape of a healthy left ventricle is often described as bullet-like or cone-shaped, tapering down to the apex.
In contrast, the base of the heart sits at the opposite end, up and toward the back. It’s formed mainly by the left atrium, with a smaller contribution from the right atrium. The large blood vessels enter the heart at the base: the two pulmonary veins on each side feed into the left atrium, and the superior and inferior vena cava drain into the right atrium. So the apex and the base are essentially bookends, with the apex pointing down and to the left and the base facing up, back, and to the right.
The Apex Beat and Why It Matters
When a doctor places a hand on your chest, they’re feeling for the “point of maximal impulse,” or PMI. This is the spot where the heartbeat pushes hardest against the chest wall, and it normally lines up with the apex. In a healthy adult, the PMI is found in the 5th intercostal space, about 7 to 9 cm left of the midline, roughly even with the middle of the collarbone.
The location of this impulse is a quick, low-tech clue about heart size. If the PMI has shifted further to the left or lower than expected, it can indicate that the heart has enlarged. In cardiomegaly (an enlarged heart), the impulse is typically displaced below the 5th intercostal space, lateral to the midclavicular line, and may be felt across two intercostal spaces instead of one. Conditions like long-standing high blood pressure, heart valve disease, and dilated cardiomyopathy can all push the apex out of its normal position.
Apex Location in Children
The apex doesn’t sit in the same spot at every age. In infants and children up to about 3 years old, the apex beat is found in the 4th intercostal space, one space higher than in adults. Between ages 4 and 7, it’s a toss-up: roughly half of children still have their apex beat in the 4th space, while the other half have migrated to the 5th. By age 8 to 10, around 70 to 80 percent of children have an apex beat in the 5th intercostal space, matching the adult position.
This gradual shift matters for pediatricians evaluating heart size in young patients. Assuming the apex should always be in the 5th space can lead to a false impression that a perfectly normal 4-year-old’s heart is abnormally positioned.
Listening to Heart Sounds at the Apex
The apex is one of the key spots where doctors place a stethoscope during a heart exam. It’s the best location for hearing sounds produced by the mitral valve, the valve that controls blood flow from the left atrium into the left ventricle. The standard listening spot is the 5th intercostal space at the left midclavicular line, directly over the apex.
Several important heart murmurs are heard most clearly here. A rumbling sound during the filling phase of the heartbeat can point to mitral valve narrowing. A murmur that lasts throughout the contraction phase at the apex may suggest a ventricular septal defect, a hole between the two lower chambers. The area between the apex and the left edge of the breastbone is also where doctors listen for signs of hypertrophic cardiomyopathy, a condition in which the heart muscle is abnormally thick.
The Apex in Cardiac Imaging
During an echocardiogram (heart ultrasound), the technician places the probe directly over the apex to capture what’s called the apical four-chamber view. This single window shows all four chambers of the heart, along with the mitral and tricuspid valves, in one image.
This view is especially useful for spotting several conditions. If the right ventricle appears equal to or larger than the left ventricle, or contracts poorly in comparison, it may signal elevated pressures on the right side of the heart, as seen with pulmonary embolism or severe pulmonary hypertension. In dilated cardiomyopathy, the left ventricle loses its normal tapered shape and balloons out into a rounder form that’s visible from this angle. The apical view also reveals pericardial effusions, where fluid collects in the sac around the heart, appearing as a dark stripe between the heart wall and the outer membrane.
The Apex as a Procedural Landmark
When fluid builds up around the heart and needs to be drained, a procedure called pericardiocentesis, the apex serves as one possible entry point. In the apical approach, a needle is inserted through the 5th or 6th intercostal space at the left midclavicular line, targeting the fluid collection near the tip of the heart. This route is particularly useful when the fluid is concentrated around the apex rather than spread evenly around the entire heart.