THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The surface of the base is quadrangular in shape and faces posteriorly and slightly to the right. Predominantly, it consists of the posterior surface of the left atrium with a smaller contribution on the right from the right atrium.

Detailed explanation-2: -The heart has five surfaces: base (posterior), diaphragmatic (inferior), sternocostal (anterior), and left and right pulmonary surfaces.

Detailed explanation-3: -Left Atrium. The left atrium is situated behind the right atrium (with the heart in situ) and forms the majority of the posterior surface, or base, of the heart.

Detailed explanation-4: -The posterior surface of the heart (base of the heart) is made up, almost entirely, of the posterior surface of the left atrium, with the left ventricle and right atrium making minor contribu-tions to this surface. The anterior surface of the heart (Figure 1) is made up largely of the right ventricle.