Assertion: pericardium | /r/HasProperty | fibrous sac
Facets:
Source sentences:
text: The pericardium is a fibrous sac called serous membrane, that encloses the heart and great vessels within the pericardial cavity (pericardial sac).
text: The pericardium is a sac of fibrous tissue that surrounds the heart and the roots of the large blood vessels.