" If you go to a mirror, open your mouth, and look at the back of the throat, you’ll see a fleshy tassel that hangs bat-like from the soft tissues. That’s the uvula. In mouths least susceptible to airway obstruction, the uvula will appear high and clearly visible from top to bottom. The deeper the uvula appears to hang in the throat, the higher the risk of airway obstruction. In mouths that are most susceptible, the uvula may not be visible at all. This measurement system is called the Friedman tongue position scale, and it’s used to quickly estimate breathing ability. "

― James Nestor , Breath: The New Science of a Lost Art