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
Pyriform sinus is laterally bounded by what ? 
Select and explain. 
A. Interarytenoid aery, B. Thyroid aery, C. Epiglottis, D. Thyrohyoid membrane
D: Thyrohyoid membrane
Answer: D: Thyrohyoid membrane 
Explanation: Ans. is `d' i.e., Thyrohyoid membrane It lies on either side of the larynx and extends from pharyngoepiglottic fold to the upper end of esophagus. ? It is bounded by :- i) Superiorly - Pharyngoepiglottic folds ii) Inferiorly - Lower border of cricoid iii) Laterally - Thyrohyoid membrane and thyroid cailage iv) Medially - Aryepiglottic fold Posterolateral surface of arytenoids and cricoid cailages