The diaphragmatic surface of the heart, directed downward and slightly backward, is formed by the ventricles, and rests upon the central tendon and a small part of the left muscular portion of the diaphragm.
Shape is slightly concave. Direction is downwards and slightly backwards. It is formed 1/3 by the right ventricle and 2/3 by the left ventricle. It is grooved by the posterior interventricular sulcus which divides it into 2 ventricles. Vessels related to it are posterior interventricular branch of right coronary artery and middle cardiac vein. It lies on the central tendon of the diaphragm and is separated from fundus of the stomach and left lobe of liver.