The<unk>  of the heart (anterior<unk>  of the heart) is directed forward, upward, and to the left.
Its lower part is convex, formed chiefly by the right ventricle, and traversed near its left margin by the anterior longitudinal sulcus.
Its upper part is separated from the lower by the coronary sulcus, and is formed by the atria; it presents a deep concavity, occupied by the ascending aorta and the pulmonary artery.
Sternocostal surface
Sternal plane
Left margin of heart
Floating rib
Transverse plane
Diaphragmatic surface of heart
Subcostal plane
Midclavicular line