What is herniated nucleus pulposus radiculopathy? l 15

Disc herniation: If i understand your question you are speaking of disc rupture or herniation at the l4-5 level. This refer to a fissure of the putter fibers of the disc called the annulus with resulting movement of the soft inner portion called the nucleus through that fissure and is putting pressure on the L5 nerve root that causes pain in the outer region of the lower leg.