Jerk test - posterior shoulder instability

Video source

• Rationale: Drives the humeral head straight backward against the posterior glenoid rim.

  
  

• Technique

  • Starting position: 90-degree abduction and internal rotation of the glenohumeral joint, and 90-degree elbow flexion. The examiner applies axial force through the humerus.

  • The tested shoulder is adducted while the axial force is maintained. The examiner stabilizes the scapula with another hand during this process.

• Positive sign: Sudden posterior shoulder pain and a click in the shoulder.

• Validity

  • LR+ 17.36; LR- 0.39 according to Morey et al. 2018

  • Good validity to confirm the condition