Atrioventricular Endocardial Cushion

Proper development of the atrioventricular endocardial cushion tissue is essential for completion of septation, generation of the fibrous portion of the inter-ventricular and inter-atrial septa and separation of the aorta from the pulmonary artery. These cushion tissue also plays a central role in formation of the cardiac skeleton, as well as of the atrio-ventricular (AV) valves and semilunar valves. By E10.5, two cushions appear, namely, the ventral AV cushion which is associated with the inner curvature and the dorsal cushion which is associated with the outer curvature.