Spine
Lumbar Spine
Evidence: uncertain
Segmental Instability Test Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Diagnosing Lumbar Segmental Instability.
How to Perform
- Step 1: Patient prone with legs off table. Examiner presses PA on lumbar spine (painful).
- Step 2: Patient lifts legs (activating muscles). Examiner presses again.
Interpretation of Results
- Positive Test: Pain is present in Step 1 but disappears in Step 2.
- Why: Muscle activation stabilizes the segment, eliminating the pain.
Diagnostic Accuracy
- Sensitivity: High for identifying responders to stabilization exercise.
Clinical Context & Limitations
The Segmental Instability Test should be considered as one component of a comprehensive musculoskeletal assessment. No single special test has perfect diagnostic accuracy; thus, clinical decision-making should integrate test results with patient-reported symptoms, mechanism of injury, functional impairment, and relevant imaging.
Clinicians should be aware of potential false-positive results in patients with pain sensitisation, muscle guarding, or poor relaxation. For the Spine region, combining the Segmental Instability Test with complementary examination tests significantly improves overall diagnostic confidence.
References
- Magee, D. J. (2021). Orthopedic Physical Assessment.
