This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Carpal tunnel syndrome involves \nSelect and explain. \nA. Median nerve, B. Anterior interosseous nerve, C. Ulnar nerve, D. Radial nerve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: CARPAL TUNNEL SYNDROME:-\n\nInjury to median nerve in carpal tunnel.\n\nCauses:-\nTenosynovitis of flexor tendons.\nMyxedema\nRetention of fluid in pregnancy\xa0\nFracture dislocation of lunate bone.\nOsteoarthritis of wrist.\nSymptoms:-\n1. Feeling of burning pain or " pins & needles " along lateral 3 and half digits especially at night.\n2. Weakness of thenar muscles.\n3. No sensory loss over thenar eminence.\n4. Ape thumb deformity if left untreated.\n5. Positive phalens and tinel\'s sign.\nPhalen\'s sign-flexion of both wrists against each other for one minute reproduces the symptoms.\nTinel\'s sign- percussion over flexor retinaculum reproduces symptoms.', 'role': 'assistant'}]