The transcerebellar ( or suboccipitobregmatic ) iew allows examination of the mid - brain and posterior fossa ; this iew is used for measurement of the transerse cerebellar diameter ( tcd ) and cisterna magna ( cm ) 经小脑平面可以检查中脑和颅后窝;该平面用来测量小脑横径( tcd )和颅后窝池( cm ) 。