Deltoid Extension Lag Sign

Published July 2, 2026 Read time 1 min read Readers 2
Deltoid Extension Lag Sign

What is the “Deltoid Extension Lag Sign” used for?

  • Axillary nerve lesion

How to perform the “Deltoid Extension Lag Sign”?

  • The patient is standing or sitting. 
  • Starting with the uninjured side, the examiner extends the arm fully ensuring no forward flexion of the trunk on the part of the patient. The patient is asked to maintain the position for 5 to 10 seconds if possible. 
  • The test is repeated on the injured side.

What is the positive result?

  • If the extension does not equal the uninjured side, then there has been an injury to the posterior deltoid muscle or its innervation, the axillary nerve, which most commonly occurs after an anterior glenohumeral dislocation.

References

  1. Abduction in Internal Rotation: A Test for the Diagnosis of Axillary Nerve Palsy – Scientific Figure on ResearchGate. Available from: Link
  2. Hertel, R et al. “The deltoid extension lag sign for diagnosis and grading of axillary nerve palsy.” Journal of shoulder and elbow surgery vol. 7,2 (1998): 97-9. doi:10.1016/s1058-2746(98)90217-8. Link