目的　为临床开展额-鼻额管区手术提供精确的形态学依据。  方法　用改进火棉胶包埋技术，制作三维连续超薄切片（0.25 mm），同时对成人脱钙尸头标本及干燥骨进行观测。  结果　鼻额管形态有斜行狭长形，直线形，弧形，倒“L”形，“S”形，其下口开口于额隐窝、筛漏斗上方、筛漏斗、筛泡上方及侧窦上方。鼻额管长度左侧为（19.81±2.56）mm，右侧为（19.90±2.60）mm。额窦形态多样，主要为三角形，额窦前壁厚度左侧为（22.48±1.72）mm，右侧为（22.63±1.38）mm。  结论　经鼻额管行额窦手术，可从中鼻道进入，找到鼻额管下口，经鼻额管直接进入额窦，手术安全可行。

Objective  To provide accurate morphological basis for clinical surgery on fronto-nasofrontal duct area.　Methods　Three-dimensional continuous thin sections of 0.25 mm was prepared with improved celloidin embedding technique and the specimens of adult decalcified heads and dry cranium were observed.　Results　The morphology of nasofrontal duct included diagonal elongated line-shape, straight line-shape, arc-shape, inverted “L” shape and “S” shape. The bottom opening of nasofrontal duct was into frontal recess, ethmoidal infundibulum and the superior part of ethmoidal infundibulum, ethmoidal bulla and lateral sinus. The length of nasofrontal duct was (19.81±2.56) mm (left) and (19.90±2.60) mm (right). Frontal sinus was diverse morphology, but triangle is the main type. The thickness of anterior wall of frontal sinus was (22.48±1.72) mm (left) and (22.63±1.38) mm (right).　Conclusion　Frontal sinus surgery via nasofrontal duct can be carried out through the middle nasal meatus after the bottom opening is found. It is safe and feasible to operate on frontal sinus directly through nasofrontal duct.