The fibroserous sac enclosing the heart and the roots of the great vessels, composed of external (fibrous) and internal (serous) layers. See also pericardial.

• adherent p. — one abnormally connected with the heart by dense fibrous tissue.
• congenitally absent p. — the heart lies free in the pleural sac; recorded in dogs.
• fibrous p. — the external layer of the pericardium, consisting of dense fibrous tissue.
• parietal p. — the parietal layer of the serous pericardium, which is in contact with the fibrous pericardium.
• serous p. — the inner, serous portion of pericardium, consisting of two layers, visceral and parietal; the space between the layers is the pericardial cavity.
• visceral p. — the inner layer of the serous pericardium, which is intimately attached to the heart and roots of the great vessels. Called also epicardium.

Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.