4.The external surface of the base of skull incisive foramen切牙孔 greater palatine foramen腭大孔 posterior nasal apertures鼻后孔 occipital condyle枕髁 hypoglossal canal舌下神经管外口 jugular foramen颈静脉孔 styloid process茎突 stylomastiod foramen茎乳孔 down4.The external surface of the base of skull Up down incisive foramen 切牙孔 greater palatine foramen腭大孔 posterior nasal apertures鼻后孔 occipital condyle 枕髁 hypoglossal canal舌下神经管外口 jugular foramen 颈静脉孔 styloid process 茎突 stylomastiod foramen 茎乳孔