fellows and interested residents should read:
Magnetic Resonance Imaging of the Lumbar Spine in People without Back Pain
Maureen C. Jensen, Michael N. Brant-Zawadzki, Nancy Obuchowski, Michael T. Modic, Dennis Malkasian, and Jeffrey S. Ross. N Engl J Med 1994; 331:69-73
http://www.nejm.org/doi/full/10.1056/NEJM199407143310201
I use these definitions of protrusion and extrusion which are somewhat different from the terms found in the next reference.
Another article is by Jarvik
http://www.ncbi.nlm.nih.gov/pubmed/11413431
Some rads quote this article in their reports.
The ASNR has collaborated with clinical spine societies and come up with:
Nomenclature and Classification of Lumbar Disc Pathology
https://www.thespinejournalonline.com/article/S1529-9430(14)00409-4/pdf?code=spinee-site
This site contains detailed descriptions of various terms.
Some important points:
Don’t use the term “far lateral” If a disc is lateral to the foramen, use extraforaminal.
One term not covered is spondylolisthesis this can be used to mean anterolisthesis or retrolisthesis. It is better to use the specific terms anterolisthesis or retrolisthesis.