"Protect against your navel getting cold
Few people realize that the navel is a vulnerable part on the body and that it is full of nerve endings under its very thin layer of skin. The navel, or belly button, is particularly sensitive to changes in temperature. "
DRAFT TO REWRITE:
This is interesting. The abdomen, and naval area is treated as a mechanical, chemical system.
There is a jump from basic digestion, to surgeries removing intestines:
In searching for proper discussion of nerves, circulation and anatomy of nerves around naval at all depths, little is shown clearly. As if intestines, nerves, fascia, are simply known about and need no extra attention beyond, basic digestion, defecation.
This page is an example of what comes up in googling naval info in summary: "below your belly button." I clicked to view and it went straight to sexual info, and anus info.