Symposium on Aspects of Anal Continence 1

The significance of an adequate sensory mechanism in the maintenance of continence is stressed and a number of important considerations are reviewed. It appears likely that several factors play a part, perhaps in varying degrees under different circumstances. The muscles of the pelvic floor and the lining of the anal canal are both capable of assisting in the fincr degrees of localization and discrimination. Summary In summary, I believe that at present we can say that the sensory component of continence is subserved by the sequential recognition of the contents by the colon, rectum, pelvic floor and anal canal. The colon and rectum provide vague and diffuse sensation, with poor localization and poor discrimination. The pelvic floor provides the first means by which the acute urge to defæcate is appreciated, and also the first and perhaps most important means of discriminating accurately between various contents of the rectum. Similar sensory appreciation is mediated by the lining of the anal canal, and although the powers of discrimination are excellent and the sensitivity acute, this should be regarded as a rather late means of achieving recognition. Patients in whom one or more of the latter two mechanisms are disturbed might reasonably be expected to develop significant postoperative defects in continence. In most young patients with congenital deformities of the ano‐rectum, and in whom the anal canal has never been present, the pelvic floor is still able to act as an accurate sensory receptor. Furthermore, its capacity in this regard can be developed to such an extent that high‐quality function can usually be achieved. On the other hand, adult patients who suddenly lose the sensory capacity of the anal canal to which they have always been accustomed frequently develop functional defects of varying severity.