English: Micrograph of myxomatous degeneration of the aortic valve. Surgical specimen. Movat's stain (Black = nuclei, elastic fibres. Yellow = collagen, reticular fibers. Blue =

ground substance, mucin. Bright red = Fibrin. Red = muscle.)

In myxomatous degeneration, the ventricularis layer (composed primarily of elastic tissue) is thinned and the spongiosa layer (composed of loose connective tissue) is thickened.

On the image, the fibrosa layer (composed of collagen) is on the top, the thickened spongiosa layer below it and the ventricularis layer (made of elastic tissue) at the bottom.

The ventricularis layer, as the name may suggest, is closest to the (left) ventricle. The fibrosa layer is closest to the sinus of valsalva.

• Marfan's syndrome - a condition, due to a defect in fibrillin (an essential component of elastic fibers), in which myxomatous degeneration is common.