pericardium morphology trait epicardium morphology trait Any measurable or observable characteristic related to the shape, structure, color or pattern of the visceral layer of the pericardium that surrounds and attaches to all the surfaces of the heart. MP:0003057 Trait.ontology VT:0003057 lamina visceralis pericardii morphology trait morphology trait of the visceral layer of serous pericardium