This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pericardium & Heart, Subject name: Anatomy
Eustachian valve is seen in - 
Select and explain. 
A. Eustachian tube opening at nasopharyngeal end, B. Eustachian tube opening in tympanic cavity, C. IVC opening in right atrium, D. Coronary sinus opening in right atrium
C: IVC opening in right atrium
Answer: C: IVC opening in right atrium 
Explanation: Ans. is 'c' i.e., IVC opening in right atrium o Opening of IVC in right atrium is guarded by - Eustachian valve (rudimentary valve). o Opening of coronary sinus in right atrium is guarded by - Semilunar valve/Thebesian valve (functional valve)