RÉSUMÉ
Lumbosacral transitional vertebra (LSTV) are congenital anomalies of the lumbosacral spine causing sacralisation or lumbarisation. Sacralisation has been defined as an abnormality where one of the transverse processes of L5 vertebra may articulate or fuse with the sacrum. The sacralisation has been studied for almost a century for its association with low back pain as “Bertolotti Syndrome”, but there are studies for and against its association. Castellvi in 1984 had propounded a radiographical classification identifying sacralisation in four sub types. Out of this, the Type IIA, is the least prevalent wherein there is a unilateral articulation of the L5 transverse process with the sacral ala. Inspite of the controversy, there is a high association of low back pain with disc degeneration, nerve root compression and degenerative facet joints observed with this condition. It is a widely researched vertebral anomaly for its anatomical, developmental and clinical ramifications.