MRI
Failure of fusion of the lateral halves of the L5 vertebral body is noted representing the butterfly vertebra. The space between the two halves is filled with adjacent intervertebral discs.
Disc bulge and ligamentum flavum hypertrophy at L5/SI level resulting impression on both lateral recesses and encroachment to right neural foramina.
Facet arthropathy and ligamentum flavum hypertrophy at lower lumbar levels.