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Ear clearing or clearing the ears or equalization is any of various maneuvers to equalize the pressure in the middle ear with the outside pressure, by letting air enter along the Eustachian tubes, as this does not always happen automatically when the pressure in the middle ear is lower than the outside pressure. This need can arise in scuba diving, freediving/spearfishing, skydiving, fast descent in an aircraft, fast descent in a mine cage, and being put into pressure in a caisson or similar pressure-bearing structure, or sometimes even simply travelling at fast speeds in an automobile.〔(【引用サイトリンク】title=Prevention of middle ear barotrauma )〕 People who do intense weight lifting, like squats, may experience sudden conductive hearing loss due to air pressure building up inside the ear. They are advised to engage in an ear clearing method to relieve pressure, or pain if any. == Methods == The ears can be cleared by various methods,〔Edmond Kay, M.D; ''Prevention of Middle ear Barotrauma'', http://staff.washington.edu/ekay/MEbaro.html〕 some of which pose a distinct risk of barotrauma including perforation of the eardrum: * Yawning which helps to open the eustachian tubes;〔 * Swallowing which helps to open the eustachian tubes;〔 * The "Frenzel maneuver": 〔 Using the rear part of the tongue and throat muscles, close the nostrils, and close the back of the throat as if straining to lift a weight. Then make the sound of the letter "K." This pushes the back of the tongue upward, compressing air into the openings of the eustachian tubes. * "Politzerization": a medical procedure that involves inflating the middle ear by blowing air up the nose during the act of swallowing;〔Silman & Arick: "Efficacy of a Modified Politzer Apparatus in Management of Eustachian Tube Dysfunction in Adults", ''Journal of the American Academy of Audiology'', October 1999; Volume 10, No. 9〕 * The "Toynbee maneuver": pinching the nose and swallowing. Swallowing pulls open the eustachian tubes while the movement of the tongue, with the nose closed, compresses air which passes through the tubes to the middle ear.〔 * The "Valsalva maneuver": pinching the nose and closing the mouth and trying to breathe out through the nose.〔〔 If the hand cannot reach the nose, it is possible to learn to pinch the nose shut by the action of two small face muscles called compressor naris. This is the first technique normally taught, but needs to be performed gently to lessen side-effects.〔 * The "Lowry Technique". A combination of Valsalva and Toynbee: pinching the nose to close the nostrils, and blow and swallow at the same time.〔 * * The nose can be closed without using a hand, using the compressor naris muscles; it can be described as "wrinkling the nose as if there was a bad smell". A hand cannot be got to the nose if using a full facemask. Many eyes-and-nose diving masks have two small pockets in their underside, or are like goggles with the soft edge extended downwards over the nose, to let two fingers reach the nose and pinch it. * The "Edmonds Technique". While tensing the soft palate (the soft tissue at the back of the roof of the mouth) and throat muscles and pushing the jaw forward and down, do a Valsalva maneuver.〔 *Voluntary opening of the eustachian tubes: Voluntary opening of the tubes: Voluntary Tubal Opening:(French: ''béance tubaire volontaire'' (BTV) ) is a method of equalising or clearing the ears described by doctor Georges Delonca and used in scuba diving and freediving. It aims to rebalance the pressure between the external ear and middle ear. :The subject must either exercise a voluntary control of the tensor veli palatini muscles opening the eustachian tubes, or move the jaw to open the tubes when necessary. This is less easy to execute than the Valsalva maneuver, but the BTV is the gentlest method to clear the ears.〔Sports Medicine, Boulevard Saint Marcel, Paris. See (Gymnastique de la trompe d'Eustache )〕 However, not all divers can perform this manoeuvre. It may be necessary to engage in ear training exercises to train the muscles to perform this manoeuvre. Another description of the method is to tense the muscles of the soft palate and the throat while pushing the jaw forward and down as if starting to yawn. This should pull the eustachian tubes open. : Some people are able to voluntarily hold their Eustachian tubes open continuously for a period of several seconds to minutes. The 'clicking your ears' can actually be heard if one puts one's ear to another person's ear for them to hear the clicking sound. Those that are borderline on learning this voluntary control first discover this via yawning or swallowing or other means; which after practice can be done deliberately without force even when there are no pressure issues involved. When the Eustachian Tubes are deliberately held open, one's voice sounds louder in one's head than when they are closed. No single method is considered safest or most successful in equalization of the middle ear pressure. Using alternative techniques may improve the success individually when a technique fails. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ear clearing」の詳細全文を読む スポンサード リンク
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