MSU Classification (Lumbar Disc Herniation)
Classifies a lumbar disc herniation on T2 axial MRI by the MSU system: size 1, 2 or 3 and location zone A, AB, B or C.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Size
- 2: more than half-way, up to the intra-facet line
- Location zone where the herniation intrudes furthest
- B: lateral quadrant
Result: MSU type 2-B: the herniation reaches more than half-way to the intra-facet line but not beyond it, and intrudes furthest into a lateral quadrant (zone B).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Size (or give both measurements instead)
- Distance from the posterior disc (or vertebral endplate) to the intra-facet line
- How far the herniation extends from that same point
- Location zone where the herniation intrudes furthest
How this is calculated
Citation
Mysliwiec LW, Cholewicki J, Winkelpleck MD, Eis GP. MSU classification for herniated lumbar discs on MRI: toward developing objective criteria for surgical selection. Eur Spine J. 2010;19(7):1087-1093. Read the sources: Mysliwiec 2010 ↗, Reliability 2018 ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.