epicardium (heart, histology)

Last reviewed 01/2018

The epicardium of the heart is the layer of the heart wall immediately superficial to the myocardium and deep to the pericardial cavity. It forms the innermost, visceral layer of the serous pericardium.

It is formed from a layer of contiguous mesothelial cells. On the outermost surface, these secrete a film of fluid that lubricates the pericardial cavity.

Deep to this layer is a layer of loose connective tissue rich in adipocytes that conforms to the superficial myocardial surface. It passes into the grooves of the heart and ensheaths the:

  • main coronary vessels
  • parasympathetic ganglia