Information on hernias?

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 (definition from MeSH). The hernia has 3 parts: the orifice through which it herniates, the hernial sac, and its contents. Since used alone "hernia" almost always refers to the passage of abdominal contents through their usual boundaries, these will be emphasized in this article; non-visceral hernias will be addressed at the end.