( 3) The posterior cranial fossa Behind the foramen magnum, there are the internal occipital protuberance枕内隆凸, sulcus for transverse sinus横窦沟, sulcus for sigmoid sinus乙状窦沟 jugular foramen颈静脉孔 internal acoustic pore内耳门 经管 downUp down Behind the foramen magnum, there are the internal occipital protuberance枕内隆凸,sulcus for transverse sinus横窦沟, sulcus for sigmoid sinus乙状窦沟, jugular foramen颈静脉孔. internal acoustic pore 内耳门 (3) The posterior cranial fossa