Pericardium

The conical sac of fibrous tissue that surrounds the heart and the roots of the great blood vessels. The pericardium’s outer coat (the parietal pericardium) is tough and thickened, loosely cloaks the heart, and is attached to the central part of the diaphragm and the back of the breastbone. Its inner coat (the visceral pericardium or epicardium) is double, with one layer closely adherent to the heart and the other lining the inner surface of the outer coat. The intervening space between these layers is filled with pericardial fluid. This small amount of fluid acts as a lubricant to allow normal heart movement within the chest.

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The fibroserous membrane, consisting of mesothelium and submesothelial connective tissue, covering the heart and beginning of the great vessels. It is a closed sac having two layers: the visceral layer (epicardium), immediately surrounding and applied to all the heart's surfaces, and the outer parietal layer, forming the sac, composed of strong fibrous tissue lined with a serous membrane. The phrenic nerves pass to the diaphragm through the anterior p. and divide the p. into antephrenic and retrophrenic portions; the pulmonary hilum divides both of these portions into suprahilar, hilar, and infrahilar portions. SYN: capsula cordis, heart sac, membrana cordis, theca cordis. [L. fr. G. pericardion, the membrane around the heart]

- adherent p. SYN: adhesive pericarditis.

- bread-and-butter p. fibrinous pericarditis in which the visceral and parietal surfaces of the p. resemble those of two pieces of buttered bread that have been pressed together and then pulled apart, when they are separated at surgery or necropsy.

- p. fibrosum [TA] SYN: fibrous p..

- fibrous p. [TA] See p.. SYN: p. fibrosum [TA].

- p. serosum SYN: serous p..

- serous p. [TA] See p.. SYN: p. serosum.

- shaggy p. SYN: fibrinous pericarditis.

- visceral p. the layer of the pericardial sac on the epicardial surface of the heart. It is composed mainly of a single layer of mesothelium.

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peri·car·di·um .per-ə-'kärd-ē-əm n, pl -dia -ē-ə the conical sac of serous membrane that encloses the heart and the roots of the great blood vessels of vertebrates and consists of an outer fibrous coat that loosely invests the heart and is prolonged on the outer surface of the great vessels except the inferior vena cava and a double inner serous coat of which one layer is closely adherent to the heart while the other lines the inner surface of the outer coat with the intervening space being filled with pericardial fluid

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n.

the membrane surrounding the heart, consisting of two portions. The outer fibrous pericardium completely encloses the heart and is attached to the large blood vessels emerging from the heart. The internal serous pericardium is a closed sac of serous membrane: the inner visceral portion (epicardium) is closely attached to the muscular heart wall and the outer parietal portion lines the fibrous pericardium. Within the sac is a very small amount of fluid, which prevents friction as the two surfaces slide over one another as the heart beats.

• pericardial adj.

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peri·car·di·um (per″ĭ-kahrґde-əm) [L.; peri- + Gr. kardia heart] 1. [TA] the fibroserous sac that surrounds the heart and the roots of the great vessels, comprising an external layer of fibrous tissue (p. fibrosum) and an inner serous layer (p. serosum). The base of the pericardium is attached to the central tendon of the diaphragm. 2. pericardial sinus.

Serous pericardium overlying the fibrous pericardium (incised and turned back).