This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
Progression of congenital scoliosis is least likely in which of the following vertebral anomalies - 
Select and explain. 
A. Fully segmented Hemivertebra, B. Wedge vertebra, C. Block vertebra, D. Unilateral unsegmented bar with Hemivertebra
C: Block vertebra
Answer: C: Block vertebra 
Explanation: Congenital vertebral anomalies causing scoliosis are :


Hemivertebrae
Wedge vertebra
Unsegmented bar
Block vertebra
Combination : unsegmented bar with hemivertebrae


Amongst these minimum chances of progression are with block vertebrae and maximum with the combination of unsegmented bar & hemivertebrae.
Unsegmented bar - with hemivertebra > unsegmented bar > hemivertebra > wedge vertebra > block vertebra