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': 'Exposure of left subclan aery by supraclavicular approach does not require cutting of ? \nSelect and explain. \nA. Sternocleidomastoid, B. Scalenus anterior, C. Scalenus medius, D. Omohyoid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Scalenus medius lies posterior to the subclan aery and thus need not be divided to expose the aery. Whereas, sternocleidomastoid & scalenus anterior lie anteriorly and omohyoid lies superiorly and thus are cut during exposure of the subclan aery.', 'role': 'assistant'}]