This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gall Bladder & Bile Ducts, Subject name: Surgery
Which of the following does not form the boundary of calots triangle - 
Select and explain. 
A. Cystic duct, B. Common hepatic duct, C. Cytic artery, D. Visceral surface of spleen
D: Visceral surface of spleen
Answer: D: Visceral surface of spleen 
Explanation: Ans. is 'd' i.e., Visceral surface of Spleen Calot's Triangle:* Calot's triangle or the hepatobiliary triangle is the space bordered by the cystic duct inferiorly, the common hepatic duct medially and the superior border by cystic artery.* This was described in 1891 by Jean-Frant^ois Calot.* It is an important surgical landmark and should be identified by surgeons performing a cholecystectomy to avoid damage to the extrahepatic biliary system.Note: In the original description by Calot the cystic artery is defined as the superior margin. But now most textbooks mention inferior surface/ border of right lobe of liver as the superior margin.