The human heart is a muscular organ positioned in the middle mediastinum, wrapped in a two-layered serous sac called the pericardium. It is shaped as a quadrangular pyramid with its base facing the posterior thoracic wall. The heart pumps blood throughout the body by circulating it through the circulatory system. The five main surfaces of the heart are the base, diaphragmatic, sternocostal, and left and right pulmonary surfaces. The heart has several margins, including the right, left, superior, and inferior margins.
Inside the heart, there are four heart chambers: two atria (right and left) and two ventricles (right and left). Blood enters the heart through the pulmonary veins, the vena cava, and the aorta. Valves separate the atria from the ventricles and the ventricles from the great vessels. The heart valves prevent backflow of blood. Blood flow through the heart is regulated by the cardiac plexus, a network of autonomic nerves subtending the heart.
Key Facts About the Heart
Borders
The heart has five borders: the superior (atria, auricles), inferior (right and left ventricles), left (left auricle, left ventricle), and right (right atrium) borders.
Surfaces
The heart has four surfaces: the sternocostal (right ventricle), diaphragmatic (mainly right ventricle, portion of left ventricle), pulmonary (cardiac impression) surfaces. The superior margin in the anterior view is formed by both atria and their auricles. The inferior margin is marked by the right ventricle.
Chambers
The heart has four chambers: the right and left atria and the right and left ventricles.
Emerging/Entering Vessels
The emerging/entering vessels of the heart include the pulmonary veins (-> left atrium), superior and inferior vena cavae (-> right atrium), aorta (left ventricle ->), and pulmonary artery (right ventricle ->).
Valves
The heart has four valves: the tricuspid, pulmonary, mitral, and aortic valves. The mitral valve is also known as the bicuspid valve. The chords tendineae connect the papillary muscles of the ventricular wall to the atrioventricular valves.
Blood Supply
The heart is supplied with oxygenated blood by the two coronary arteries: the left and right coronary arteries. The coronary circulation supplies every part of the heart with oxygenated blood.
Coronary Sinus
The coronary sinus is a large vessel that delivers deoxygenated blood from the myocardium to the right atrium.
Great Vessels of the Heart
The great vessels of the heart are the aorta, pulmonary artery, pulmonary vein, and superior and inferior vena cava. These large-diameter vessels carry blood to and from the heart.
Clinical Notes
There are many disorders that can affect the heart and its adjacent structures, such as angina pectoris, infective endocarditis, and congenital heart disease.
Sources
All content published on Kenhub is reviewed by medical and anatomy experts. The information provided is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice.
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- {Surface projections of the heart}
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