Fig. 1From: Value of nerve root sedimentation sign in diagnosis and surgical indication of lumbar spinal stenosisBraz classification (using vertical bisector of median sagittal diameter of dural sac cross section): (a) negative: the nerve root settles on the dorsal side of the dural sac under the action of gravity; (b)positive: the nerve roots are suspended, dispersed in the dural sac, or even floating to the ventral side of the dural sacBack to article page