The heart is a four-chambered muscular organ with a complex structure that allows it to efficiently pump blood throughout the body. It is divided into two halves—the right and left sides—each responsible for different aspects of circulation. In an adult, the heart is approximately equal to the size of a clenched fist. The broader base lies upward slightly towards the right side part of the sternum, while the significant portion of the pointed apex lies slightly left to the sternum facing the diaphragm. Learn about the heart anatomy, including its chambers, valves, blood flow, and coronary circulation. See diagrams, videos, quizzes, and clinical notes on the heart structure and functions. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest, called the mediastinum. [4]
