A brachial plexus injury occurs when the network of nerves that runs from the neck through the shoulder and down the arm (called the brachial plexus) becomes stretched, compressed, or torn. These nerves control movement and sensation in the shoulder, arm, and hand. Depending on how severe the injury is, symptoms can range from mild weakness or numbness to complete loss of function in the arm. Standing next to a wall, place your palm on it with your fingers pointing down and your arm straight. Ge