新生儿喉位于 C4 水平 ,喉体向前下倾斜 ,鼻部阻力占总气道阻力的 4 9% ,只有哭闹时有张口呼吸。至出生后 2～ 5个月逐渐学会用口呼吸 ,此前任何鼻腔通道的缺陷都有生命危险。近 10年 CT可用于诊断和评估新生儿后鼻孔闭锁。但部分鼻腔狭窄系阻塞而非后鼻孔闭锁引起 ,如鼻腔粘膜 Neonatal laryngeal C4 level, the throat forward tilt, nasal resistance accounted for 49% of the total airway resistance, only when there is a mouth crying cry. 2 to 5 months after birth, gradually learn to use mouth breathing, defects in any nasal passages have life-threatening. Nearly 10 years CT can be used to diagnose and assess neonatal nostril atresia. However, some nasal stricture obstruction rather than posterior nostril atresia caused, such as nasal mucosa