In posterior shoulder dislocation, the anteromedial aspect of the humeral head hits the posterior glenoid and becomes impacted posterior to it which is called Trough line sign in Plain radiograph. This crush results in bony defect of the anteromedial humeral head analogous to Hill-Sachs so that called Reverse Hill-Sachs sign. Also the posterior glenoid labrum is torn and considered Reverse Bankart lesion.