This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
The mesentery of small intestine, along its attachement to the posterior abdominal wall, crosses all of the following structures except 
Select and explain. 
A. Left gonadal vessels, B. Third pa of duodenum, C. Aoa, D. Right ureter
A: Left gonadal vessels
Answer: A: Left gonadal vessels 
Explanation: The root of mesentry lies on the right side of abdominal cavity and crosses right gonadal vessels (not left) The root of the mesentry lies along a line running diagonally from the duodenojejunal flexure on the left side of the second lumbar veerbral body to the right sacroiliac joint. It crosses over the third (horizontal) pa of the duodenum, aoa, inferior venacava, right ureter and right psoas major. It does not cross the left ureter, left gonadal vessels or superior mesenteric aery. Superior mesenteric aery is a constant of the mesentry. Ref: Gray's Anatomy 41st edition Pgno:1168