The anal cushions are composed or erectile tissue similar to that in the penis. This is developed to enormous size in some gibbons and mandrills, where it is a sexual signal, but in man it's more modest function is to seal the anal canal and prevent seepage. We showed that... Read more »

Anorectal Function

The anus is much cleverer than we like to think. Or maybe we don't like to think about it at all, unless it fails or is too up tight. It is, in fact, two sphincters in one, the outer one under conscious control, the inner not. It is exquisitely... Read more »