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': "Klumpke's palsy is due to injury to the following nerves: \nSelect and explain. \nA. Inferior trunk of the brachial plexus, B. Superior trunk of the brachial plexus, C. Subscapular nerve, D. Ulnar nerve", 'role': 'user'}, {'content': 'Answer: A \nExplanation: The upper trunk (C5 and C6) is the most common area injured and results in the classic Erb palsy. Injury to the lower trunk (C7-T1) produces a Klumpke palsy. Klumpke palsy is characterized by good shoulder function but decreased or absent hand function. Brachial plexus injuries may also cause a Horner syndrome (unilateral miosis, ptosis, and facial anhidrosis) due to disruption of cervical sympathetic nerves. Ref: Wilson P.E., Clayton G.H. (2012). Chapter 28. Rehabilitation Medicine. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.', 'role': 'assistant'}]