ches in length, three and a half inches in the broadest part of its transverse diameter, and two and a half inches in its antero-posterior. The average weight in the male varies from ten to twelve ounces. In the female, the average weight is eight to ten ounces. The heart will continue to grow in size up to an advanced period of life. This growth is more obvious in men than in women.3Circulation of Blood in an Adult: The heart is subdivided by a longitudinal muscular septum into two lateral halves which are named right and left according to their position. A transverse muscle divides each half into two cavities. The upper cavity on each side is called the atria/auricle, and the lower side is called the ventricle. The right atrium and ventricle form the venous side of the heart. Dark venous blood is pumped into the right atrium from the entire body by the superior (SVC) and inferior vena cava (SVC), and the coronary sinus. From the right atrium, the blood passes into the right ventricle and from the right ventricle, through the pulmonary artery into the lungs.3 Once the blood becomes oxygenated/arterialized by its passage through the lungs, it is returned to the left side of the heart by the pulmonary veins which open into the left atrium. From the left atrium, the blood passes into the left ventricle where it is distributed by the aorta and its subdivisions through the entire body.Morphology of Each Heart Chamber: The right atrium is a little longer than the left. Its walls are also somewhat thinner than the left. The right atrium is capable of containing about two ounces of fluid. It consists of two parts, a principle cavity/sinus, and an appendix auriculae. The sinus is a large quadrilateral-shaped cavity located between the IVC and the SVC. Its walls are extremely thin and are connected on the lower surface with the right ventricle and internally with the left atrium. The rest of the right atrium is free...
