A seated flexion test is positive on the right. On the dysfunctional side, the sacral base is deep and the ILA is shallow. What is the most likely sacral diagnosis?

• A. Right unilateral shear flexed
• B. Right unilateral shear extended
• C. Left axis rotation
• D. Bilateral extension

Answer: (A)

The key idea is using the seated flexion test to localize the sacral dysfunction and then reading the sacral landmarks to determine flexed vs extended on the involved side. A positive seated flexion test on the right means the right sacrum is the dysfunctional side. If, on that side, the sacral base is deep and the ILA is shallow, this specific pattern corresponds to a unilateral shear with the sacrum in a flexed position on the right. So the right sacrum has rotated forward relative to the ilia on that side. That combination points to a right unilateral shear flexed.

The other possibilities don’t fit this pattern: a right unilateral shear extended would show the opposite base/ILA relationship, left axis rotation would typically yield a positive seated flexion test on the left with a different landmark pattern, and bilateral extension would present with symmetrical findings rather than a unilateral pattern.