Question

The vein that does not directly open into the heart is:

• A. Pulmonary vein
• B. postcaval vein
• C. Precaval vein
• D. Posterior mesentric vein

Answer 1

The correct option is D Posterior mesentric vein

• The pulmonary vein opens directly into the left atrium while postcaval and precaval veins into the right atrium.
  
• The posterior mesenteric vein is a blood vessel that drains blood from the small intestine (jejunum and ileum). At its termination behind the neck of the pancreas, it combines with the splenic vein to form the hepatic portal vein and hence does not open into the heart.
  

So, the correct option is 'Posterior mesenteric vein'.