Image from WikipediaThe Straight Dope: Why are some belly buttons "innies" and others "outies"?Dear Cecil:
You may not think the following question is too cosmic, but let's face it, the topics you address in your column seldom are. How come some belly-buttons are "innies" and some are "outies"? --M.E.L., Los Angeles
Cecil replies:
You may think this column is trivial, M. I think you just don't grasp the implications. Assuming the attending physician didn't bungle the job, the incidence of "innies" and "outies" appears to be random. 
The accepted procedure for cutting the umbilical cord, which is usually done a few minutes after birth, is to place two clamps on it near the junction with the kid--an ordinary surgical clamp on the placenta end and a special plastic gizmo on the kid end, a centimeter or two from the abdomen. Then you cut in the middle.
Within a week or so the stub becomes necrotic (i.e., dead) and falls off, leaving, ideally, a concave scar. The vagaries of fetal development and the healing process being what they are, however, sometimes you get an "outie," which, apart from any embarrassment it may occasion at the beach, is harmless.
Worse things can happen. Sometimes the skin of the abdominal wall doesn't reach the base of the cord, and a wide raw area is left that heals slowly. This is called an amniotic navel. Other disorders can result in urine or other bodily fluids leaking through the navel.
If things really aren't going your way, you may be born with a ghastly deformity called an omphalocele, in which the intestines bulge out through the abdominal wall by way of the navel. I'm in no hurry to discuss this in detail. Be grateful.
--CECIL ADAMS
