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to allow water to flow into the middle ear to equalize the pressure. BEFORE you feel the slightest pressure in your ears, you need to equalize. The Eustachian tube opening in the throat is normally closed. Most people can open the tube by flexing the muscles at the back of their throat or jaw. If you listen closely, you can hear a slight crackling sound inside your head when you yawn, swallow, or move your jaw forward. Some divers are fortunate and can equalize or clear their ears by swallowing or wiggling their jaw. Most divers require a bit more effort to open the tube and equalize the pressure. The most common method for equalizing pressure in the middle ear is simple. You close your mouth tightly or block it with your tongue (on scuba), close your nostrils by pinching them shut, and then exhale lightly (figure 4-22). As you build a slight pressure in your head, you should hear the pressure open the tube with a gentle pop, which signals that air has flowed into the Eustachian tube. You must never force this technique. You could seriously damage your ears. This maneuver works well for most divers. The key NAUI Scuba Diver 108 Diving Science Ear Drum Oval Window Round Window Auditory Nerves Cochlea (Hearing Organ) Eustachian Tube to Throat FIGURE 4-21. THE MIDDLE EAR SPACE IS CONNECTED TO THE THROAT BY THE EUSTACHIAN TUBE. AIR PASSES THROUGH THIS TUBE TO EQUALIZE PRESSURE IN THE MIDDLE EAR. FIGURE 4-22. THE MANEUVER MOST COMMONLY USED FOR EQUALIZING THE PRESSURE IN YOUR EARS IS A SIMPLE BLOWING EFFORT.


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