The main function of the human heart is to pump blood around the body. It is a muscular cone shaped organ, the average size of the human heart is the size of a clenched fist and weights on average eleven ounces. The heart is located underneath the sternum in a compartment called the mediastinum. About two-thirds of the hearts mass is located to the left of the body midline. The narrow end of the heart is called the apex. It is directed downward and to the left and lies above the diaphragm. The broad end of the heart is called the base and gives rise to the major blood vessels. The heart consists of four chambers, two atria and two ventricles. Blood enters the right atrium and passes through the right ventricle the right ventricle pumps blood to the lungs where it becomes oxygenated. The oxygenated blood is brought back to the heart. The two ventricles are separated by a thick myocardial wall called the inter-ventricular septum. On the anterior surface of the heart the inter-ventricular septum is marked by a shallow groove called the anterior inter-ventricular sulcus, which holds adipose tissue, the great cardiac vein and the anterior inter-ventricular artery. (Jones 1984) insert image
The major vessels of the heart are the large arteries and veins that attach to the atria and the ventricles and transport blood to and from the pulmonary circulatory system and the systemetic circulatory system. Blood is received to right atrium from the systematic circulatory system by the superior vena cava and the inferior vena cava, blood leaves the right ventricle through the pulmonary artery. These vessels branch out into the left and right pulmonary arteries, and