Depending on the fissure is visible or not,the disease could be divided into two types:(1)fuse type,the apposite layers of the gray matter cleft clung each other and the fissure closed.

• 根据裂隙能否被肉眼看出可分为 :(1)融合型 :特点为裂隙前后的灰质层相贴或融合 ,裂隙关闭 ;