Are outie bellybuttons more, less or equally as ticklish as innie bellybuttons?
Hey @footlover1682! This is a tricky question. I'll do my best to give an answer, but most of my research was pretty inconclusive.
Let's dive into the anatomy of the bellybutton and the distinction between innie and outie first.
Bellybutton Formation:
When you're born, the doctor cuts off your umbilical cord and leaves a small "stump" behind. How this stump eventually falls off is what determines the kind of bellybutton you have (not how the doctor cut the cord or how well your parents cared for the stump).
In short, your bellybutton is a scar! And whether it is an innie or an outie depends on how the skin grows as it heals.
Bellybutton Anatomy:
Before your umbilical cord is cut, one vein and two arteries act as the main suppliers of nutrients from mother to baby. After it's cut, those dry up and harden into ligaments that are still attached to the inside of your bellybutton.
One of these ligaments connects and bisects the liver, while the other stretches down into the pelvis (where portions may still function as part of the circulatory system near the bladder - hence why needing to pee is a common reaction when the navel is pushed).
These ligaments sit along your abdominal wall. Thus, it's the nerves within the surrounding abdominal muscles that are most likely being stimulated during navel tickling.
Innies vs Outies:
Only 10% of the population has an "outie" bellybutton!
Outie bellybuttons are caused either from a tiny umbilical hernia or a small infection leading to the formation of granulation tissue. And while this sometimes requires medical attention, often its left alone as the "outie" navel that we all know and love!
Bellybutton Sensitivity:
Ultimately the nerves and muscles are the same regardless of whether you have an innie or an outie bellybutton.
However...
From a logical perspective, outie bellybuttons have more accessible surface area for tactile stimulation since they protrude distinctively on the stomach.
Meanwhile, innie bellybuttons require a more technical touch because (1) you need to be mindful of pressure to prevent abdominal pain from intruding tools/fingers and (2) the nerves and skin are less accessible since it is within the folds of the navel itself.
Based on that reasoning, I would say that innie bellybuttons can be less ticklish, but only because the Tickler can more easily tickle an outie than an innie.
