The most resistive site in the FS averaged 1.75cm distant from the nostril In noimal subjects alar muscles constricted isometrically during respiration so as to keep the vestibular airway stable.

• 产生NAR的最主要部位在距前鼻孔缘平均约1.；75cm处。 正常人鼻翼肌随呼吸运动发生等长收缩，以此维持鼻翼部气道稳定不变。