A pilonidal cyst is a unique kind of abscess that occurs in or above the crease of the buttocks. Pilonidal cysts often begin as tiny areas of infection in the base of the area of skin from which hair grows (the hair follicle).
Cofferdam A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed.
A series of these sunken panels were used as decoration for a ceiling or a vault, also called caissons ('boxes), or lacunaria (spaces, openings), so that a coffered ceiling can be called a lacunar ceiling: the strength of the structure is in the framework of the coffers. coffer (or coffering) in architecture, is a series of sunken panels in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault.