The shear test for the sacroiliac (SI) joint assesses the joint's stability and identifies potential pain sources. Several variations exist, but they all involve applying a shearing force across the SI joint to provoke pain. A positive test indicates possible SI joint dysfunction.
Types of SI Joint Shear Tests
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Thigh Thrust Test (Posterior Shear Test): This commonly used test involves the patient lying supine (on their back). The examiner applies an anterior-to-posterior shear force to the SI joint through the patient's femur (thigh bone). Pain localized to the SI joint indicates a positive result. Multiple sources describe this technique. [See references detailing the thigh thrust/femoral shear test](https://www.researchgate.net/figure/Thigh-Thrust-Test-Posterior-Shear-Test-With-the-patient-lying-in-a-supine-position_fig2_355148285, https://www.painteq.com/types-of-si-joint-provocative-tests-for-diagnosing-si-joint-dysfunction, https://mikereinold.com/assessing-the-sacroiliac-joint-the-best-tests-for-si-joint-pain/).
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Sacroiliac Shear Test (Prone Position): Another variation involves the patient lying prone (on their stomach). The examiner places hands over the patient's tailbone and applies a downward force. Pain reproduction suggests SI joint involvement. A source mentions this prone position test.
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Other Provocative Tests: It's important to note that the shear test is often part of a cluster of provocative tests used to assess the SI joint. These tests help differentiate SI joint pain from other sources of low back pain. See reference on Sacroiliac Joint Special Test Cluster.
Important Note: These tests should only be performed by qualified healthcare professionals. Positive results don't definitively diagnose SI joint dysfunction, but rather contribute to the overall clinical picture, aiding in the diagnosis and treatment plan.
