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: Pathology
The commonest type of spinal T. B. is - 
Select and explain. 
A. Posterior, B. Paradiscal, C. Pedicle, D. Anterior
B: Paradiscal
Answer: B: Paradiscal 
Explanation: The commonest type of spinal T.B. is paradiscal.
In this contiguous areas of 2 adjacent vertebrae along with intervening disc are affected.
This special pattern of involvement is seen because of the embryology of the vertebra.
The lower half of one vertebra and upper half of the one below it, along with the intervening disc develop from pair of sclerotomes and have a common blood supply.