||It has been suggested that Fibrous pericardium and Serous pericardium be merged into this article. (Discuss) Proposed since August 2014.|
Walls of the heart, showing pericardium at right.
Posterior wall of the pericardial sac, showing the lines of reflection of the serous pericardium on the great vessels
The pericardium (from the Greek περί, "around" and κάρδιον, "heart") 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.
The pericardium fixes the heart to the mediastinum, gives protection against infection, and provides the lubrication for the heart.
Pericardium is a tough double layered fibroserous sac which covers the heart. The space between these two layers is filled with serous fluid which protects the heart from any kind of external jerk or shock. There are two layers to the pericardial sac: the outermost fibrous pericardium and the inner serous pericardium. The serous pericardium, in turn, is divided into two layers, the parietal pericardium, which is fused to and inseparable from the fibrous pericardium, and the visceral pericardium, which is part of the epicardium. The epicardium is the layer immediately outside of the heart muscle proper (the myocardium).
The visceral layer extends to the beginning of the great vessels (the large blood vessels serving the heart) becoming one with the parietal layer of the serous pericardium. This happens at two areas: where the aorta and pulmonary trunk leave the heart and where the superior vena cava, inferior vena cava and pulmonary veins enter the heart.
- Surrounds heart and bases of pulmonary artery and aorta.
- Deep to sternum and anterior chest wall.
- The right phrenic nerve passes to the right of the pericardium.
- The left phrenic nerve passes over the pericardium of the left ventricle.
- Pericardial arteries supply blood to the dorsal portion of the pericardium.
- Fixes heart in mediastinum and limits its motion
- Protects it from infections coming from other organs (such as lungs)
- Prevents excessive dilation of the heart in cases of acute volume overload
- Lubricates the heart
An excess of fluid in the cavity (such as in a pericardial effusion) can result in cardiac tamponade (compression of the heart within the pericardial sac). A pericardiectomy is sometimes needed to remedy this.
- This article uses anatomical terminology; for an overview, see anatomical terminology.
- Anatomy photo:21:st-1500 at the SUNY Downstate Medical Center - "Mediastinum: Pericardium (pericardial sac)"
- thoraxlesson4 at The Anatomy Lesson by Wesley Norman (Georgetown University) (heartpericardium)