For Testing the sacrum or SI joint I do: 1) Seated flexion test: affected side moves first and and further cranially 3) Sit slump -for a backward sacral torsion (BST) the obliquity gets worse with extension and for forward sacral torsion (FST) the obliquity gets worse with flexion or slump 4) lumbo-sacral spring test: usually painful  and stiff with a BST and springy/ not painful with FST. 5) sacral spring for mobility