Functional Coloproctology is the last enigma in medicine where the factors maintaining normal continence and defecation are still unclear at the dawn of the new millennium. The use of flow equation suggests new definitions for A.I. and constipation from the flow point of view, determines the primary mechanical factors maintaining continence & defecation. It also suggests how the sensory and reflex factors interact with the mechanical factors in order to maintain continence and initiate normal defecation. All these factors can be measured numerically in health and disease. ...