The commonest type of spinal T. B. is -

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.