the fibrous sac covering of the heart which is in contact with the pleura is the
Pericardium The pericardium is a double-walled sac containing the heart and the roots of the great vessels. The pericardial sac has two layers, a serous layer and a fibrous layer. It encloses the pericardial cavity which contains pericardial fluid.
Chordae tendineae The chordae tendineae (tendinous cords), colloquially known as the heart strings, are tendon-resembling fibrous cords connective tissue that connect the papillary muscles to the tricuspid valve and the bicuspid valve in the heart.