Execution
- 1Position the patient prone with the trunk on the table and the legs over the table edge with the feet resting on the floor.
- 2Apply posterior-to-anterior pressure to each lumbar segment while the patient rests in this position.
- 3Ask whether the pressure reproduces the patient’s pain.
- 4Ask the patient to lift both legs off the floor while maintaining the trunk on the table.
- 5Repeat the same posterior-to-anterior pressure and compare symptom response.
Positive outcome
The test is positive when posterior-to-anterior pressure is painful with the feet on the floor but the pain decreases or disappears when the legs are lifted. Magee explains that muscle contraction during leg lift masks the instability. The test suggests functional segmental instability or stabilization-responsive pain rather than proving radiographic instability.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Hicks et al. (2003) — reliability supported | NA | NA | NA | NA | NA |
| Fritz et al. (2005) | NA | NA | NA | NA | NA |
CommentMagee calls this the prone segmental instability test and describes the classic pain-relief-with-co-contraction response. Reliability is better than many palpation tests, but radiographic instability accuracy is not strong enough for stand-alone diagnosis. It is most useful as part of the Hicks stabilization CPR or a broader instability assessment.
Low Clinical Value