The base of the heart is oriented posteriorly and to the right. The left atrium mainly forms it.
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Inferior surface of heart
The inferior surface of the heart, also known as the diaphragmatic surface, faces downward. It is composed of the ventricles and lies on the diaphragm.
Left surface of heart
Left surface of the heart is directed towards the left lung.
Right surface of heart
Right surface of the heart is oriented towards the right lung, and it is formed mainly by the right atrium
Anterior surface of heart
The anterior surface of the heart, also known as the sternocostal surface, is composed of the right atrium and predominantly of the right ventricle.