Lumbar spine MRI showing a lateral disc extrusion impinging the L5 nerve root

(A) Sagittal T1-weighted MRI shows a disc extrusion (arrow) at the L4-5 disc level.
(B) Axial T2-weighted image at the L4-5 disc level shows the disc extrusion to be left paracentral in location (arrow), obliterating the left lateral recess where the descending L5 nerve root would be expected. Note the normal appearing right descending L5 nerve root within the contralateral lateral recess just prior to its exit from the thecal sac (arrowhead).