Human Anatomy - M.M. Kurepina, A.P. Ozhigova, A.A. Nikitina 2010

Cardiovascular System
Heart
Topography of the Heart

The Heart is located behind the Sternum (Atlas, Fig. 51) in the anterior Mediastinum. It is enclosed in the pericardial sac, or Pericardium (pericardium). The visceral layer of the latter, known as the epicardium, covers the heart Muscle and is continuous with the parietal layer (the pericardium proper) along the large Blood Vessels. Between them lies a closed cavity containing about 20 ml of serous fluid. The pericardium is a nearly inextensible membrane formed by interlacing elastic and Collagen fibers. Its inner surface is lined with mesothelium (a simple squamous epithelium), which facilitates the gliding motion of the epicardium and pericardium against each other. Through loose Connective Tissue, the pericardial sac is anchored anteriorly to the sternum and the cartilages of the true Ribs, laterally to the mediastinal PARTS OF THE parietal Pleura, and posteriorly it is in contact with the Esophagus, descending aorta, and azygos vein, being firmly fused with the Diaphragm only at its base.

The pericardium covers not only the heart but also the proximal segments of the major vessels arising from it: the ascending aorta, the pulmonary trunk, portions of the superior and inferior venae cavae, and the Pulmonary Veins. Thus, the pericardium helps anchor the heart in place via the great vessels.

The long axis of the heart lies at an angle of 40–45° to the sagittal plane of the thoracic cavity, extending from the midpoint of the third thoracic vertebra to the fifth left intercostal space just below the junction of the costal Cartilage and bone of the fifth rib. The heart projects very slightly beyond the right margin of the sternum. Its apex comes into contact with the anterior chest wall in the fifth left intercostal space; it is here that the apical impulse can be felt during ventricular contraction. Consequently, the heart is positioned asymmetrically: two-thirds of it lie in the left half of the thoracic cavity and one-third in the right. This Asymmetry is unique to humans and evolved in connection with upright posture.



Last update: 08/08/2026

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