Fig. 2
From: Incidence of numerical variants and transitional lumbosacral vertebrae on whole-spine MRI
15-year-old boy with back pain. Sagittal T1-weighted image (a) and coronal reformats of a sagittal SPACE sequence (b) demonstrate a transitional lumbosacral vertebra. Counting from the top, this is a lumbarised S1 vertebra. This can also be identified on an anterior-posterior (AP) radiograph (c) of the whole spine, better appreciated on a magnified view of the lumbar spine only (d). The only reliable method for determining the nature of a transitional vertebra is to count from the top