Nerve Compression Question

This picture should help with the question asked today about lumbar herniations.

Basically the L4 nerve passes and exits JUST above where the disc herniates, so the only nerve left that it can compress will be L5. The L4 disc will basically be the floor of the foramina that the L4 nerve exits, so even if it protrudes, it won't make a difference for that nerve, but will compress L5 before it exits the spinal column.