nerve entrapment: repeated and long-term nerve compression (usually in nerves near joints that are subject to inflammation or swelling)
nerve compression: harmful pressure on a nerve (especially in nerves that pass over rigid prominences); causes nerve damage and muscle weakness
hirschsprung's disease: congenital condition in which the colon does not have the normal network of nerves; there is little urge to defecate so the feces accumulate and cause megacolon