If a part of One's body is inside of a cast, it has a plaster cast close to it to safeguard it though a broken bone repairs by itself:
: a mass of plastic issue shaped in cavities of diseased organs (given that the kidneys) and discharged from the body
a : an overspread of the coloration or modification of the appearance of a material by this site a trace of some extra hue : shade grey with a greenish cast