This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
All structures pass through aortic opening Diaphragm except- 
Select and explain. 
A. Aorta, B. Sympathetic trunk, C. Thoracic Duct, D. Azygos vein
B: Sympathetic trunk
Answer: B: Sympathetic trunk 
Explanation: Ans. B. Sympathetic trunkThere are a number of openings in the diaphragm through which structures pass between the thorax and abdomen.There are three large openings--the aortic, the esophageal, and the caval opening--plus a series of smaller ones.The aorta does not pierce the diaphragm but rather passes behind it in between the left and right crus. Structures passing through aortic opening are aorta, Thoracic Duct & Azygos vein.