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: Anaesthesia
[{'content': 'Interscalene approach to brachial plexus block does not provide optimal surgical anaesthesia in the area of distribution of which of the following nerve – \nSelect and explain. \nA. Musculo cutaneous, B. Ulnar, C. Radial, D. Median', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ulnar nerve is usually spared by interscalene approach because injection is given in close proximity of upper nerve roots and inferior nerve roots (C8-T1) may be spared.', 'role': 'assistant'}]