Posterior glenohumeral instability is tested by

Answer: b) Jerk testSulcus Sign. Downward traction is applied to the arm while the shoulder is held in 0 degrees of abduction, neutral rotation, and 0 degrees of flexion/extension. The acromiohumeral interval is measured to assess inferior glenohumeral laxity.Rotator Interval Test. While performing the sulcus test, externally rotate the arm. Healthy patients will have a reduction of inferior translation. No reduction in acromiohumeral interval is suspicious for rotator interval capsular deficiency.Jerk Test. Start with the arm forward-flexed and adducted. Posterior-directed force will cause posterior translation in posterior instability. Moving the arm into the coronal plane may reduce the humeral head.