Make your hand into a fist. This is roughly the size of your heart. If you could open up your own chest, you would find your heart behind your breastbone, nestled between your lungs. Each lung has a notch, the cardiac impression, that the heart fits into. Your heart sits on a slant, leaning into your left lung so that it is slightly smaller than your right lung. Reach into your chest cavity and pull your lungs away from your heart to fully appreciate the complexity of this organ.
