Erb's palsy occurs due to involvement of

ERB'S PARALYSIS:- upper plexus injury.Caused by forceful widening of the angle between the head and shoulder which may occur by traction of 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, forearm is extended and pronated. 1. Adduction of arm due to deltoid paralysis.2. Medial rotation of arm-paralysis of supraspinatus, infraspinatus and teres minor.3. Extension of elbow- paralysis of biceps brachii4. Pronation of forearm- paralysis of biceps brachi5. Loss of sensation over outer aspect of arm due to C6 spinal nerve involvement.{Reference: vishram singh, page no. 62}