Policeman's tip hand is seen in?

ERB'S PARALYSIS:- Caused by a forceful widening of the angle between the head and shoulder which may occur by traction of the arm during the bih of a child or by fall on the shoulder.Involves upper trunk - C5, C6 roots. Leads to typical deformity in the limb- policeman's tip hand/ poer's tip hand. The arm hangs by the side, adducted and medially rotated, the forearm is extended and pronated. DISABILITY: The following measures are lost. Abduction and lateral rotation of the arm at the shoulder joint. Flexion and supination of the forearm. Biceps and supinator jerks are lost. Sensations are lost over a small area over the lower pa of the deltoid. {Reference: BD Chaurasia page no. 59}.