Pericardial fluid is the serous fluid secreted by the serous layer of the
pericardium into the
pericardial cavity. The pericardium consists of two layers, an outer fibrous layer and the inner serous layer. This serous layer has two membranes which enclose the pericardial cavity into which is secreted the pericardial fluid. The fluid is similar to the
cerebrospinal fluid of the brain which also serves to cushion and allow some movement of the organ.