Where is the heart? Position behind the sternum, apex and four chambers

Where is the heart?

People often say the heart is on the left, but it actually sits closer to the middle: centred behind the breastbone, with about two-thirds of it extending to the left. You feel the beat more on the left because the tip points that way.

In the view above the heart is highlighted in yellow; teamLabBody divides it by chamber, and here the left ventricle is selected with the other chambers highlighted. It lies in the mediastinum between the lungs, resting on the diaphragm, with the sternum and ribs in front and the oesophagus, descending aorta and spine behind. It is often likened to a little more than the size of the person's fist.

Orientation: apex and base

Position and orientation vary with build, breathing and posture; textbook figures are typical values.

Four chambers and the flow of blood

The right side serves the lungs and the left side the body, so the left ventricular wall is thicker. Valves guard each outlet: tricuspid and mitral between atria and ventricles, pulmonary and aortic at the ventricular exits.

Name and terms

The Greek is kardia, hence cardio- and cardiac. Related terms: atrium, ventricle, apex of heart, base of heart. The Latin is cor.

See it in the app

Inside the ribs and behind the sternum, how far the heart lies to the left and how its chambers overlap are hard to see in a front drawing. In the 3D anatomy app teamLabBody you can make the bones translucent to see its position, then select and rotate each chamber; add the aorta and venae cavae to see the vessels gather at the base. Cross sections are available with the PREMIUM plan.

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