The endocardial cushion is a critical structure in the developing heart of the embryo. It plays a vital role in the formation of the heart's septa and valves. Located in the atrioventricular (AV) canal and the outflow tract, these cushions are essential for proper heart morphogenesis. They are composed of extracellular matrix (ECM), mesenchymal cells, and later, endothelial cells that contribute to the formation of the septa and valves.
