Lumbosacral unilateral transitional vertebra

Clinical presentation

Middle aged lady with low back ache. To rule out urolithiasis.

Non contrast CT abdomen


Diarthrodial  L5 vertebral body which has two articular margins, one through the L5-S1 body articulation, another anomalous one through the right transverse process. Sclerosis also seen involving the iliac portion of bilateral sacroliliac joints. No urolithiasis.

Learning points

  • Transitional vertebrae are a cause of lower abdominal / low back ache in comparison to normal individuals. The extra articular surface and the secondary osteodegeneration of that joint limiting ipsilateral mobility is responsible.
  • Multiple classifications are available for lumbosacral transitional vertebrae.

Read more

  1. Lumbosacral transitional vertebra – Radiopaedia