Left on left axis; a seated flexion test is negative; the sacral bases are both shallow and the ILAs are both deep. What is the diagnosis?

Left on left axis; a seated flexion test is negative; the sacral bases are both shallow and the ILAs are both deep. What is the diagnosis?

• A. Left-on-left torsion
• B. Right-on-right torsion
• C. Bilateral extension
• D. Bilateral flexion

Answer: (C)

Interpreting sacral motion dysfunction from how the sacral sulci and ILAs present together with the seated flexion test is key here. A negative seated flexion test means there isn’t a sacral torsion along an oblique axis. When both sacral bases are shallow and both ILAs are deep, that pattern fits a sacrum that’s extended on a bilateral basis: the base sits more posteriorly (shallow on palpation) and the posterior ilia accommodate with deeper ILAs. In contrast, bilateral flexion would show the opposite pattern (bases deep and ILAs shallow). So, the combination described points to bilateral sacral extension.

Interpreting sacral motion dysfunction from how the sacral sulci and ILAs present together with the seated flexion test is key here. A negative seated flexion test means there isn’t a sacral torsion along an oblique axis. When both sacral bases are shallow and both ILAs are deep, that pattern fits a sacrum that’s extended on a bilateral basis: the base sits more posteriorly (shallow on palpation) and the posterior ilia accommodate with deeper ILAs. In contrast, bilateral flexion would show the opposite pattern (bases deep and ILAs shallow). So, the combination described points to bilateral sacral extension.