Elbow
Neurological (Nerve Entrapment)
Evidence: suggestive
Scratch Collapse Test Special Test
Orthopedic Physical Examination & Clinical Assessment Guide
What is it used for?
- Detecting nerve compression (Ulnar or Median).
How to Perform
- Step 1: Patient resists bilateral shoulder external rotation (baseline strength).
- Step 2: Examiner scratches the skin over the suspected nerve entrapment site.
- Step 3: Immediately re-test shoulder strength.
Interpretation of Results
- Positive Test: Temporary loss of muscle resistance (collapse) due to cutaneous gating reflex.
Diagnostic Accuracy
- Sensitivity: 69%
- Specificity: 99%
Clinical Context & Limitations
The Scratch Collapse 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 Elbow region, combining the Scratch Collapse Test with complementary examination tests significantly improves overall diagnostic confidence.
References
- Magee, D. J. (2021). Orthopedic Physical Assessment.
