What Is a Lumbosacral Transitional Vertebra on an X-Ray or MRI?

Short answer: a lumbosacral transitional vertebra means the lowest lumbar bone and upper sacral area have anatomy that is partly blended or shaped differently than usual. Reports may use words like sacralization or lumbarization.

What the wording usually describes

This is often an anatomic variant. It matters when clinicians are trying to identify the exact spinal level, compare imaging studies, or decide whether pain could be coming from nearby discs, joints, or the SI-joint region.

Details that make the finding more or less important

whether the report mentions sacralization, lumbarization, or numbering uncertainty
whether symptoms are one-sided near the low back, buttock, or hip region
whether other levels are described as degenerated or narrowed
whether prior imaging used different numbering
whether a planned procedure or surgical consultation requires exact level confirmation

How to discuss it at a pain visit

Bring the full report rather than only the impression. If procedures are being discussed, exact level numbering and image correlation are important safety details.

Related PSG resources: lower back pain, sacroiliac joint pain, and pain management.

Sources include NCBI Bookshelf - Lumbosacral Transitional Vertebrae, AAOS OrthoInfo - Low Back Pain, RadiologyInfo - MRI Spine. This article is educational and cannot diagnose the cause of pain from an imaging phrase alone.

Author