As mentioned in the previous slide, the heart has an apex and a base. 

Apex of heart

The apex of the heart is pointed forward, downward, and to the left. It is typically located deep to the left fifth intercostal space and slightly medial to the left midclavicular line (an imaginary line drawn parallel to the long axis of the body and crossing the middle of the clavicle). The cardiac apex is formed by the inferolateral part of the left ventricle.

Base of heart

The base of the heart is oriented upward, backward, and to the right. It is formed mostly by the left atrium and a small posterior portion of the right atrium. The cardiac base is positioned at the level of the third costal cartilage. It is separated from the fifth through eighth thoracic vertebrae (T5 - T8) by the esophagus, thoracic duct and descending thoracic aorta.