[Physiology of fecal continence and defecation]

Defaecation is a complex function that requires interactions between the somatic and autonomic nervous systems. Moreover, social living standards lead to self-control of continence involving supraspinal nervous structures. After a brief description of the anatomy of the hind gut, the various reflex mechanisms underlying faecal continence and defaecation are exposed; the specificities of the nervous control of the smooth and striated muscles brought into play in these events are detailed. Then the main useful investigations allowing to localize the nervous structures at the origin of the anorectal disorders are reviewed.