Prolapsed interveebral Disc is most common at-

L5-S1 disc space is the most commonly involved space in disc prolapse. "Lumbar interveebral disc herniation is most common at L5-S1 and slightly less common at L4 - L5, and rare at L3-L4 or above". "The disc at L5-S1 is most commonly involved, followed in order by L4-L5 and L3-L4". REF : MAHESWARI 9TH ED