This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of Larynx, Subject name: ENT
Direct bronchoscopy can visualize all except: 
Select and explain. 
A. Trachea, B. Vocal cords, C. First segmental subdivision of branch, D. Subcarinal lymph nodes
D: Subcarinal lymph nodes
Answer: D: Subcarinal lymph nodes 
Explanation: Ans. is 'd' i.e. Subcarinal lymph nodes Subcarinal lymph nodes are not visualized by bronchoscopy (quite obviously). However transbronchial needle aspiration of subcarinal lymph node can be done, even without its direct visualization. It can be visualized using endoscopic ultrasound.