You're 5 years old, and word on the playground is that if you sneeze with your eyes open, they'll pop right out of your head. Given that you've got a nasty cold, this rumor is relatively terrifying for you. After all, what could be worse than your eyeballs shooting out of your face like bullets?
Now let's fast-forward to adulthood, a time in which you're no longer terrified of eyeball expulsion but nevertheless still wonder about that sneezing myth of yore. Does it have any truth to it? Exactly how securely are your eyeballs attached to your head?
To debunk this myth, let's first take a look at what's going on inside the body during a sneeze. Sneezing is a protective mechanism that the body uses to expel dust, pollen, pet hair and other allergens. Some people sneeze when they're exposed to cold air. It's common to sneeze when you have a cold because the inside of the nasal cavity becomes swollen and more sensitive than usual. This sensitivity triggers sneezing at the slightest irritation.
The act of sneezing is involuntary, but the body goes through a very systematic process during the act. When an irritant comes in contact with the nasal lining, the nerves in the area send a message to the lower portion of the brain, known as the medulla. The brain then triggers the activity necessary for the body to sneeze:
The muscles in the chest expand, the diaphragm contracts, and the lungs fill with air. The muscles that are in the back of the throat and vocal cords also contract, and then the stomach and chest muscles follow suit. Finally, the sneeze is expelled through the mouth, sending between 2,000 and 5,000 droplets of mucus and air flying away from the body at between 70 and 100 miles per hour (112.6 and 160 kph) [source: Washington Post]. The spray from a sneeze can extend 5 feet (152.4 centimeters) from the sneezer [source: Library of Congress]. This spray is made up of saliva and mucus. Expelling the mixture through the mouth clears the nasal cavity.
One other thing happens during this process: Your eyes squeeze shut. But why? There's got to be some legitimate reason, right?