Perioperative nerve injuries can be a complication of surgical procedures and accounts for approximately 16% of all anesthesia-related claims in the United States. Whereas ulnar neuropathy at the elbow is the most common, other nerve injuries of the upper extremity and the phrenic nerve are not rare occurrences. A number of possible etiologies have been proposed to explain perioperative nerve injury to include stretch, compression, ischemia, and metabolic derangement. There appears to be additional factors making some patients more prone to nerve injury than others, for example, the sex of the patient and pre-existing disease. Also, in some cases there is a discrepancy between the timing of the surgery and the injury manifestations that can be the result of delayed recognition or an insult in the postoperative setting.