Heart in situ (with pericardium) (English)

Anterior view. The heart is separated from other structures of the mediastinum by a double layered fibroserous sac called the pericardium. On its surface are important vessels which supply and drain the pericardium and diaphragm, known as the pericardiacophrenic artery and vein. The right and left phrenic nerves, which innervate the diaphragm, course laterally on either side of the heart; these are clinically important since they can be damaged during surgical interventions to the heart.