Test library › Shoulder & upper arm
External rotation lag sign
For: Infraspinatus tear
A tear in the infraspinatus, the rotator cuff tendon at the back of the shoulder that turns the arm outwards (external rotation).
Best used to rule inLR+ as published by the study; the rounded percentages shown would give a lower LR+ (about 5).
What the numbers mean
- Positive result: a moderate rule-in: a positive result makes the diagnosis clearly more likely.
- Negative result: barely informative: a negative result changes little.
Source
Jain NB, Luz J, Higgins LD, Dong Y, Warner JJP, Matzkin E, Katz JN. The Diagnostic Accuracy of Special Tests for Rotator Cuff Tear: The ROW Cohort Study. Am J Phys Med Rehabil. 2017;96(3):176–183. PubMed · single study
Figures as they will appear in Rule It In, Rule It Out (Trokos, forthcoming). If a newer or better study changes them, this page changes with the book. Figures last updated from the book on 2 October 2026.
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This page gives the published figures. Rule It In, Rule It Out adds how to do this test, what counts as positive, how to read the result, and, where studied, whether combining it with other tests helps.
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Rule It In is a free evidence letter for musculoskeletal clinicians: one recent study explained, one examination test with its real numbers. From Trokos, publisher of Rule It In, Rule It Out.