User:Bob K31416/BH

The base of the heart, directed superiorly, posteriorly, and to the right, is separated from the 5th, 6th, 7th, and 8th thoracic vertebrae by the esophagus, aorta, and thoracic duct.

It is formed mainly by the left atrium, and, to a small extent, by the back part of the right atrium.

The apex of the heart is the lowest superficial part of the heart.

It is directed downward, forward, and to the left, and is overlapped by the left lung and pleura.

The base of the heart is the part of the border of the heart that is located opposite the apex. It involves the left atrium, to a smaller extent the right atrium, and the parts of the great vessels nearest to  the heart.