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
Klumpke's palsy is due to injury to the following nerves? 
Select and explain. 
A. Inferior trunk of the brachial plexus, B. Superior trunk of the brachial plexus, C. Subscapular nerve, D. Ulnar nerve
A: Inferior trunk of the brachial plexus
Answer: A: Inferior trunk of the brachial plexus 
Explanation: 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.