Wow. Neither of those pics look like the standard anatomy book view of a couple of turns to the vertical, a turn to the horizontal and a turm to the descending.
Nope, they don't, do they? Of course, my toes and nose don't look exactly like the textbook either, so when I ran across mention of the barium enema images, I thought I'd try to find some. Both of those came from a google image search, and there a more out there. Each one a little different. I hope that these images may help some to better understand their own plumbing.
When I was much younger we lived in the country and I occasionally spent some time laying/playing naked in the yard. It was almost an example of how many things I could do wrong all at once, but using a garden hose (careful of the sharp/rough threaded end) layed in the yard to heat in the sun ( no temperature regulation) kinked in my hand except when I wanted flow, or slipped, or got distracted (no real pressure or flow control) and inflating at each stage to apply pressure and force to open the next restriction (probably not the best idea), I was able to make it past the curve at the top of my descending. I do not know/remember how far in that was, but I had to help turn the leading edge of the hose from pointing out my left side to towards my right side, and then it would slide in a bunch more. I do recall that where I held the hose after its outbound trip was about three feet from the end, so I would guess that means about 30" inside. I would fill so full of water that I looked pregnant, and sometimes had difficulty getting it all out (to look normal again) when I was done.
One of these days I am going to mae or buy something like the shower shot but with a relief valve, and try to replicate this experience.
Anyways, sorry for the tangent, I hope I have helped a little.
