@danny5 Good question, Danny. Spondylolisthesis describes vertebrae slipping past each other a bit because the disc between them is not strong enough to prevent this. If they say anterolisthesis that means slipping forward and retrolisthesis is slipping backward.

A herniation in a disc happens when the fibrous outer wall has breached and allowed some of the jelly like stuff inside called the nucleus to escape. That is a disc that is weak and likely would allow vertebrae to slip past each other. Herniated discs loose some of their height. My herniated disc was 50% of what it had been. When the nucleus escapes it causes inflammation and often this causes osteophytes (bone spurs) to grow next to the extruded disc material. When that happens, they refer to it as a disc-osteophyte complex. I had that too. This happened in my cervical spine, and it has been corrected with a single level fusion.

L5 is the lowermost disc in the lumbar spine right above the sacrum, and they refer to that level as L5 S1. The sacrum has a few attached levels, and the tailbone is attached to that at the very end of the spine.

Jennifer