A 7-year-old boy falls from a tree house and is brought to the emergency depament of a local hospital. On examination, he has weakness in rotating his arm laterally because of an injury of a nerve. Which of the following conditions is most likely to cause a loss of this nerve function?
Injury to the lateral cord of the brachial plexus supracondylar fracture humerus Knife wound on the teres major muscle Inferior dislocation of the head of the humerus