In a case where a seated flexion test is positive on the right and on the dysfunctional side the sacral base is shallow and the ILA is deep, what is the diagnosis?

• A. Bilateral flexion/extension
• B. Posterior torsion
• C. Right unilateral shear extended
• D. Left unilateral shear rotated

Answer: (C)

The main idea is that the seated flexion test localizes the dysfunction to the sacrum on the side where the test is positive, and palpation of the sacral landmarks (sacral base and ILA) shows which pattern of dysfunction is present.

Here, the seated flexion test is positive on the right, so the right side is the dysfunctional sacrum. On that same side, the sacral base is described as shallow and the ILA as deep. That specific pattern fits a unilateral shear of the sacrum where the sacrum has rotated about a transverse axis toward the right and is in extension on that side. In other words, the right side is sheared and extended.

So the findings point to a right unilateral shear extended. This pattern would be different from bilateral flexion/extension or from a posterior torsion, which would show a different combination of landmark asymmetries and a different seated flexion pattern.