THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -In order to maintain proper function, the heart and roots of the great vessels are encased within a double-walled fibrous sac termed the pericardium. On each side of the heart, the pericardium acts as the medial border of the pleural space.

Detailed explanation-2: -The pericardial sac positions the heart in the mediastinum and limits its motion while providing a lubricated slippery surface for the heart to beat inside and the lungs to move outside.

Detailed explanation-3: -The pericardium, also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), and an inner layer made of serous membrane (serous pericardium).