A.2~3mm B.3~5mm C.5~10mm D.10~12mm E.12~15mm
A.經(jīng)迷路進路 B.顱中窩進路 C.迷路后進路 D.乙狀竇后進路 E.迷路枕下聯(lián)合進路
A.<1% B.2%~3% C.5% D.8% E.20%