Problem:

I am confused regarding the presence of valves in the superior vena cava.

The superior vena cava does not possess valves unlike inferior vena cava, which possesses Eustachian Valve.

Question: Where are Haversian valves present?

Question: Aren't they present at the opening of caval i.e., superior vena cava.

Question: Why is it said that there is absence of valves in superior vena cava?

Please provide discription of all the answers.