The ventral, or front, surface of the heart is distinguished by its curvature, whereas the backside is much flatter, notes Shannan Muskopf for The Biology Corner. It features a large pulmonary trunk that extends off the top and auricle flaps that cover the atria.
The front side of the heart is often identified by the coronary sinus that runs across it at an angle, says Muskopf. The auricle is a flap that looks like an ear covering the atrium. The pulmonary trunk enters the top of the heart at an angle in front of the aorta. The four major vessels that enter the heart are the pulmonary trunk, aorta, superior vena cava and pulmonary vein. The two atria are located at the top, and the two ventricles are located at the bottom.
The surface of the heart has several distinctive features that are anatomically and clinically important, states Sophie White for TeachMeAnatomy. The heart is described in many textbooks as "a pyramid which has fallen over." In its typical orientation, the heart has five surfaces formed by various internal divisions and four borders that separate the different surfaces. The locations of the left and right atria and the left and right ventricles determine where these surfaces and borders appear.