Execution
- 1Position the patient standing with the elbows flexed to 90° by the sides, shoulders neutral, and forearms / wrists neutral.
- 2Ask the patient to externally rotate and abduct the forearms against balanced isometric resistance.
- 3Let the patient relax.
- 4Scratch along the course of the ulnar nerve at the elbow or another suspected compression site.
- 5Immediately retest resisted external rotation / abduction for 2 to 3 seconds.
Positive outcome
Transient weakness or collapse on the second resisted external-rotation / abduction test on the affected side is positive. Magee describes the finding as positive for ulnar nerve neuropathy when scratching is performed over the ulnar nerve path.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Cheng et al. (2008) | NA | 69 | 99 | 69 | 0.31 |
| Montgomery et al. (2020) | poor to fair interrater reliability in later evaluation | NA | NA | NA | NA |
CommentMagee includes MacKinnon’s scratch collapse test and the hierarchical version for localizing multilevel compression. Cheng’s original study reported high specificity, but later work and systematic reviews have questioned reliability and reproducibility. Because of that controversy, a positive result should support rather than replace standard cubital tunnel assessment.
Moderate Clinical Value