Intimal cushion explained

The intimal cushion is smooth muscle in the center of arteries that paradoxically keep the artery patent by serving as valves. It is present in Helicine arteries of penis and in the patent ductus arteriosus.^[1]

References

1. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1626120 The paradoxical patent ductus arteriosus