Hernia

A hernia is a protrusion of a tissue, structure, or part of an organ through the muscular tissue or the membrane by which it is normally contained. The hernia has 3 parts: the orifice through which it herniates, the hernial sac, and its contents.

A hernia may be likened to a failure in the sidewall of a pneumatic tire. The tire's inner tube behaves like the organ and the sidewall like the body cavity wall providing the restraint. A weakness in the sidewall allows a bulge to develop, which can become a split, allowing the inner tube to protrude, and leading to the eventual failure of the tire.