Erb's Palsy (Erb-Duchenne Palsy, Brachial plexus paralysis) is a paralysis of the arm cause by injury to the upper group of the arm's main nerves (specifically, spinal roots C5-C7), almost always occuring during birth. Depending on the nature of the damage, the paralysis can either resolve on its own over a period of months, necessitate physical therapy or require surgery.