Anatom3DAnal canal
Canalis analis · Řitní kanál
Digestive system
Looks like
The last 3–4 cm of the gut, a closed slit running down and back from the rectum to the anus, ringed by the internal and external sphincters.
What it does
Holds stool in and lets it out at will: the inner sphincter works on its own, the outer one on command.
Keeping it well
Below its dentate line the lining feels pain like skin: a tear there (fissure) hurts sharply with every stool. Bleeding from the back passage over 50, or a change in habit, needs checking.