A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body.

What is it encloses the heart?

The Pericardium. The pericardium is the fibrous sac that surrounds the heart. It can be divided into three layers, the fibrous pericardium, the parietal pericardium, and the visceral pericardium.

What encloses the heart in the chest?

The pericardium is a thin sac that surrounds your heart. It protects and lubricates your heart and keeps it in place within your chest.