This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Extremity, Subject name: Anatomy
[{'content': "The 'ape-thumb deformity' occurs due to lesion of: \nSelect and explain. \nA. Radial nerve, B. Median nerve, C. Ulnar nerve, D. Musculocutaneous nerve", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. B. Median nerveThe 'ape-thumb deformity' is lack of ability to abduct and oppose the thumb due to paralysis of the thenar muscles. It can occur with an injury of the median nerve either at the elbow or the wrist, impairing the thenar muscles and opponents pollicis muscle.", 'role': 'assistant'}]