Duh… that’s so obvious. Just kidding. What could possibly be the connection between a tweezed eyebrow hair and a sneeze?

The sneezing reflex is a complex, almost Rube Goldbergian sequence of physiological events. It typically starts with an irritation to your nasal passages that excites your trigeminal nerve. (No, it doesn’t take much to get a trigeminal nerve excited.) Then these impulses are transmitted through the trigeminal ganglion to a set of neurons in the brain stem called the sneezing center. The sneezing center then sends impulses back along the facial nerve to your nasal passages, mucus glands, blood vessels, and eyelids, which is the reason you close your eyes when you sneeze. (Impulses from the sneezing center also travel to nerves that control muscles in your abdomen, chest, diaphragm, and neck.)

Plucking a hair from your eyebrow stimulates a nearby branch of the nerve that services your nasal passages. And even though these impulses don’t originate in your nose, the eyebrow plucking sensitizes the entire nerve, enabling sufficient impulses to reach the sneezing center… and you sternutate (that’s sneeze, in dorky doctorspeak).

So whether you’re shaping those ultra-feminine crescents or manscaping that unibrow, here’s a hearty “Gusundheit!” for the next time you pluck.