Conclusions : When anterior wall of Sylvian cistern is being cut in pterion approach it is not easy to injury M1 . A quarter of the veins in sphenoidal segment of Sylvian cistern are wrapped up in arachnoid sheath and should not be taken as arachnoid to break .

结论：经翼点入路手术中，切开 大脑 外侧 窝池前壁时，不易 伤及M1段主干。