This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb bones and muscles (proximal region) & Scapular movements, Subject name: Anatomy
[{'content': '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? \nSelect and explain. \nA. Injury to the lateral cord of the brachial plexus, B. supracondylar fracture humerus, C. Knife wound on the teres major muscle, D. Inferior dislocation of the head of the humerus', 'role': 'user'}, {'content': "Answer: D \nExplanation: Inferior dislocation of the head of the humerus may damage the axillary nerve, which arises from the posterior cord of the brachial plexus, runs through the quadrangular space accompanied by the posterior humeral circumflex vessels around the surgical neck of the humerus, and supplies the deltoid and teres minor, which are lateral rotators of the arm. Injury to the lateral cord of the brachial plexus-branches of lateral cord are -musculocutaneous and lateral root of median nerve injury to these nerves doesn't affect lateral rotation. supracondylar fracture humerus -m/c nerve injured is anterior interocious nerve Knife wound on the teres major muscle- teres major is a medial rotator of shoulder", 'role': 'assistant'}]