The paper has summarized systematically evolutionary law in time and space on petrofacies and paleogeography of Late Paleozoic era in Northern China and distributive law of depositional systems.

根据华北晚古生代沉积岩系环境标志,识别出29,并为冲积扇、河流、三角洲、潮汐砂滩、碳酸盐台地等6沉积体系。

Performation of surgical procedures anterior to ethmoid bulla can avoid risks of the other models, therefore, endoscopic frontal sinusotomy in the route anterior to ethmoid bulla is a safe model.

结论通过鼻内镜对额窦开口及周围解剖结观察，认为星状裂作为恒定解剖标志是识别额窦开口关键区域。筛泡前径路是鼻内镜下额窦开放入路，能避免其他径路存在某些风险。