Nasopharyngeal stenosis, one of the symptoms of obstructive sleep apnea, is an increasingly common condition in which the upper airway repeatedly collapses during sleep, causing decreased oxygen saturation as well as sleep disruption. Symptoms include snoring, apnea, and daytime sleepiness. The pathogenesis of obstructive sleep apnea varies, and predisposing factors include a narrow upper airway, unstable respiratory regulation, low arousal threshold, low lung capacity, and dysfunction of the dilator muscles of the upper airway. So what are the triggers of nasopharyngeal stenosis? 1.Nasal factors Nasal columella is too wide, nasal valve area stenosis, anterior nostril stenosis or atresia, nasal septum deviation, nasal polyps, hypertrophic rhinitis, sinusitis, nasal tumors, nasal foreign body, nasal filling, and other nasal cavity obstructive lesions, can lead to the occurrence of this disease. Due to the obstruction of the nasal airway, it is necessary to increase the inhalation force too much, which increases the negative pressure in the pharynx and causes the collapse of the airway. 2.Pharyngeal factors According to the observation of pharyngeal electromyography during the sleeping period, all the pharyngeal muscles are found to be in a state of relaxation. Through X-ray and fiberoptic endoscopy, it is confirmed that the soft tissues of the pharyngeal wall are atrophied during the inspiratory period, and the outer and posterior pharyngeal walls just fall down to the oropharyngeal inlet, resulting in obstruction. Overlength or hypertrophy of uvula, hypertrophy of proliferator or tonsil, pharyngeal tumor, pharyngeal stenosis, parapharyngeal or retropharyngeal abscess, pharyngeal muscle paralysis, pharyngeal muscle relaxation, etc., are the most common and important causes of snoring. 3.Tongue factors Macroglossia, tongue thyroid, tongue tumor, tongue drop, cellulitis of the floor of the mouth and so on. 4, congenital maxillofacial deformities, including Pierre-Robin syndrome (small jaw, tongue drop, cleft palate); Colin-Treacher syndrome (small jaw, figure-eight ocular cleft, bird-shaped face, external ear deformity); Prader-Willi syndrome (obesity, facial deformities, dysphagia, sexual hypogonadism); Down syndrome (maxillary hypoplasia, low-flat nose, high palate). Down syndrome (maxillary hypoplasia, low flat nose, high arched palate, mental retardation); Crozon syndrome (acromegaly, orbital distance widening, short upper lip, parrot beak external nose, mandibular hypoplasia). 5.Laryngeal factors Including inflammatory swelling of the larynx, laryngeal chondromalacia and tumor. During sleep, the root of tongue falls back and presses the epiglottis to cover the vestibule of the larynx, resulting in obstruction of the respiratory tract, causing reflex closure of the vocal folds and apnea. Neck factors: thyroid tumor, scar contracture after burns or radiotherapy in the front of the neck.