Semilunar valves which are located in the outflow tracts of the ventricles The outflow of each chamber is guarded by a heart valve:Ītrioventricular valves between the atria and ventricles The cardiac wall or heart wall consists of the following layers from inside to the outside: The ventricles are separated by two grooves, one of which, the anterior longitudinal sulcus, is situated on the sternocostal surface of the heart, close to its left margin, the other posterior longitudinal sulcus, on the diaphragmatic surface near the right margin these grooves extend from the base of the ventricular portion to a notch, the incisura apicis cordis, on the acute margin of the heart just to the right of the apex. The interatrial groove, separating the two atria, is scarcely marked on the posterior surface while anteriorly it is hidden by the pulmonary trunk and ascending aorta. The atria are separated from the ventricles by the coronary sulcus (atrioventricular groove) this contains the trunks of the nutrient vessels of the heart and is deficient in front, where it is crossed by the root of the pulmonary artery. The division of the heart into four cavities is indicated on its surface by grooves. The heart, therefore, consists of four chambers: The heart is subdivided by septa into right and left halves, and a constriction subdivides each half of the organ into two cavities, the upper cavity being called the atrium, the lower the ventricle.

Superiorly: bifurcation of the main pulmonary trunk Posteriorly: esophagus, descending thoracic aorta, azygos, hemiazygos veins, and thoracic duct RelationsĪnteriorly: the body of the sternum, and adjoining costal cartilages left lung, and pleura (apex) The heart measures 12 x 8.5 x 6 cm and weighs ~310 g (males) and ~255 g (females) 1. Its left-sided orientation is formally known as levocardia (cf. It is positioned posteriorly to the body of the sternum with one-third situated on the right and two-thirds on the left of the midline. Its base (roughly square-shaped) points posterior while its apex points to the left and inferiorly 7.

The heart has a somewhat pyramidal form and is enclosed by the pericardium.

Structure of heart download