Human Anatomy - Kotsan I. Ya. 2009

Cardiovascular System
Circulatory System
Pericardium

The Pericardium, or Heart sac, is a closed fibroserous sac that separates The Heart from adjacent Organs. It consists of two layers: an outer layer, the fibrous pericardium (pericardium fibrosum), and an inner layer, the serous pericardium (pericardium serosum).

The outer layer of the pericardium, or fibrous pericardium, blends with the adventitia of the great vessels at the Base of the heart. On all sides, the fibrous pericardium fuses with surrounding structures: a) inferiorly, with the central tendon of the Diaphragm; b) laterally, with the mediastinal Pleura; c) anteriorly, with the anterior chest wall, forming the sternopericardial ligaments (ligg. sternopericardiaca).

The inner layer of the pericardium, or serous pericardium, comprises two membranes: a parietal layer (lamina parietalis), which lines the inner surface of the fibrous pericardium, and a visceral layer (lamina visceralis), which covers The Heart and forms its outer coat, the epicardium. The parietal and visceral layers of the serous pericardium are continuous with each other at the base of the heart in the region of the great vessels emerging from it. Between the parietal and visceral layers lies a slit-like space, the pericardial cavity (cavitas pericardialis), which surrounds the heart and contains a small amount of serous fluid (liquor pericardii). This serous fluid lubricates the opposing surfaces of the parietal and visceral layers, thereby reducing friction during cardiac contractions, and also serves a bactericidal function. At the transition sites between the parietal and visceral layers, deep recesses—known as pericardial sinuses—are formed, where exudate may accumulate during heart disease. These include the transverse pericardial sinus (sinus transversus pericardii), located at the base of the heart posterior to the aorta and pulmonary trunk, and the oblique pericardial sinus (sinus obliquus pericardii), situated on the diaphragmatic surface of the heart and bounded by the left Pulmonary Veins and the INFERIOR VENA CAVA on the right.

Blood supply to the pericardium is provided by the pericardial Branches of the Thoracic Aorta and branches of the superior phrenic Arteries. The pericardial veins, which accompany the corresponding arteries, drain into the brachiocephalic, azygos, and hemiazygos veins.

The Lymphatic vessels of the pericardium drain into the pericardial, lateral pericardial, and anterior and posterior mediastinal Lymph Nodes.

The nerve supply to the pericardium is derived from branches of the phrenic and vagus nerves, as well as the cervical and thoracic cardiac nerves arising from the Sympathetic trunk ganglia.