Q. A 26-year-old boy is brought to the emergency room with severe right shoulder pain. He holds his right upper extremity in slight abduction and external rotation, supports it with his left hand, and cannot move his right upper extremity. The injury happened 30 minutes ago during a fight in the boxing ring when his opponent dodged him. Distal pulses are normal and capillary refill is 1-2 sec. The shoulder x-ray shows anterior dislocation of the shoulder. You want to evaluate the most commonly injured nerve in anterior shoulder dislocation; how do you examine it?