Second Ring Confusion

[Nocturn13]

Hey guys,

This is my first post but I have read a few of these second ring threads and they are pretty confusing to me.

There are only 2 sphincters within the area being discusses (anal canal, rectum, and sigmoid colon) and they are both within the anal canal (internal and external sphincters)

The anal canal is ~1.5 inches long

The rectum is ~6 inches long

From first sphincter to the end of the rectum (where there is a change in direction to form an S shape) that is ~ 7.5 inches (varies from person to person)

So is the second ring people are talking about where that change in direction is? Given the inches people are saying it is being reached at it would see that is what is being referred to, because after the internal sphincter there are no more rings (until you get to the other sections of colon)

I am genuinely curious as to what is being referred to, if this is a fantasy type of thing I apologize for bringing in real life.

(I am in medical school so this is all from lectures/textbooks/gross anatomy lab)

[Pig Bottom]

Fist ring is the anus, the second is the sigmoid colon.