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: ENT
[{'content': 'In emergency tracheostomy following structures are damaged except: \nSelect and explain. \nA. Isthmus of thyroid, B. Inferior thyoid vein, C. Inferior thyroid aery, D. Thyroid ima', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Structures which lie below the midline viz. isthmus of thyroid and thyroid ima aery can be damaged in emergency tracheostomy. Inferior thyroid veins emerge at the lower border of the isthmus form a plexus in front of the trachea and drains into brachiocephalic vein can be damaged during tracheostomy but inferior thyroid aery, a branch of thyrocervical trunk of subclan aery lies laterally away from midline and can thus escape injury.', 'role': 'assistant'}]