People With This Tiny Ear Hole Have a Rare Feature: The Science of the Preauricular Sinus
What Exactly Is a Preauricular Sinus?
A preauricular sinus is essentially a microscopic, blind-ended tunnel or tract that travels underneath the skin near the front of the outer ear.
Instead of being a simple surface-level dimple, it forms a small subterranean pathway that can occasionally branch out into the surrounding subcutaneous tissue. In the vast majority of cases, it occurs on only one side of the head (unilateral), though roughly 25% to 35% of people born with the feature have them on both ears (bilateral).
Who Has It? (Global Prevalence Rates)
The likelihood of being born with this unique facial feature depends heavily on geographic ancestry and ethnic background:
- Regions of Europe and North America: It is exceptionally rare, appearing in only about 0.1% to 0.9% of the population.
- Regions of Asia and parts of Africa: It is significantly more common, with prevalence rates climbing to anywhere between 4% and 10% of the population.
The Evolutionary and Biological Explanations
Why are some people born with a microscopic tunnel built into their ear structure? Scientists look at this through two distinct lenses: embryological development and evolutionary history.
