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': 'The structure damaged in High Tracheostomy ? \nSelect and explain. \nA. Thyroid isthmus, B. Aoic knuckle, C. First tracheal ring, D. Recurrent laryngeal nerve', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is'c' i.e., First tracheal ring(Ref: Dhingra dle p' 317)High tracheostomy: Performed above the level of thyroid isthmus which lies against II, III and IV tracheal rings:Indicated in carcinoma larynx when laryngectomy is anticipated.Drawback : tracheostomy at this point violates the 1st ring of trachea and causes perichondritis of the cricoid cailage and subglottic stenosis, so it is better avoided.", 'role': 'assistant'}]