A young man with a suspected dislocated shoulder had his shoulder "reduced." This is a fancy medical term meaning they put the shoulder back in the socket. Since they had to manipulate the man's shoulder many times to get it back in, the doctors failed to recognize that they damaged the nerve leading from the armpit to the hand.
Importantly, there was fluid that compressed the nerve in the arm, causing a decrease and ultimately a total lack of blood flow to the nerve. The doctors failed to timely recognize this nerve injury. When they finally recognized the problem and took the patient into surgery, the damage had already been done, leading to permanent nerve injury.