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The Frenzel Maneuver is named after Hermann Frenzel (German ear, nose and throat physician and Luftwaffe commander). The maneuver was developed in 1938 and originally was taught to dive bomber pilots during World War II. The maneuver is used to equalize pressure in the middle ear. Today, the maneuver is also performed by scuba divers, free divers and by passengers on aircraft as they descend.〔(【引用サイトリンク】title=Prevention of middle ear barotrauma )〕 The Frenzel Maneuver is performed as follows:〔〔 * the way out of the nasal cavity is blocked, typically by pinching the nostrils or by a nose-clip; * the way out of the mouth cavity is blocked by the tongue, either performing an alveolar closure (as when the sound () or () is produced; this is the standard version) or a velar closure (using the back of the tongue; this is the advanced version, leaving very little possibility for the piston movement by the tongue, mentioned below); * the larynx is closed, sealing off the lungs; * the body of the tongue (or only the back of the tongue, if velar closure has been made) is gently moved upwards and backwards, in order to compress the air; * further compression of the air follows from moving the closed glottis upwards (this is easily noticed in the elevation of the "Adam's Apple"). By performing this technique, the compressed air is forced into Eustachian tubes, and thus into the middle ear. In situations where the ambient pressure rises (typical causes are decreasing altitude in the case of an airplane or increasing depth in the case of a diver submerging), the maneuver results in the equalization of the pressure on both sides of the eardrum.〔〔 Compared with the Valsalva maneuver, the Frenzel maneuver carries a significantly lower risk of over-pressurizing the middle or inner ear; given e.g. a nose-clip, it also allows hands-free equalisation. The maneuver can be done at any time during the respiratory cycle and it does not inhibit venous return to the heart.〔(【引用サイトリンク】title=Venous Return - Hemodynamics )〕 Effort to perform the maneuver is minimal, and it can be repeated many times quickly. == References == 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「Frenzel maneuver」の詳細全文を読む スポンサード リンク
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