The “rib” is just a polite way of saying cut down the middle.
Nah, it's not a "rib" that's the sanitized version.
Humans are one of the only mammals without a literal dick bone. The myth was good created Eve (the second wife) out of the dick bone. And that's why humans don't have a dick bone.
Not even being funny:
Penile bones are common in the skeletal structure of male mammals, particularly carnivores and primates where they function anatomically as a stiffening rod. Lacking this bone, human males must rely on fluid hydraulics to maintain an erection. The ancient writer of our story asked himself a question: Why do human males lack this bone? His answer was that it had been taken from Adam to make woman.
https://library.biblicalarchaeology.org/article/was-eve-made-from-adams-rib-or-his-baculum/
The "zipper line" according to the myth is how God removes the dick bone:
We find the answer in a little-noticed physical condition in men. A slight seam of light flesh, referred to as a perineal raphé, exists on the underside of the human penis. When a male fetus is about ten weeks old, the edges of the urogenital groove on the underside of the penis begin to fold together over the urogenital sinus (cavity). This process leaves a scar where the two sides come together. Most men are unaware of it, but it is in fact visible after birth and throughout life as a straight line of scar tissue on the underside of the penis.
It appears that the Bible here ascribes the origin of this scar/seam to the “closing of the flesh” after the os baculum was removed from Adam’s penis to form the woman. It responds to the question: Where does that particular scar-like line come from?