Q.The sphincter of Oddi guards
a. Hepatopancreatic duct
b. Common bile duct
c. Pancreatic duct
d. Cystic duct

Step 1. Recall the duct anatomy: the common bile duct (from the liver and gall bladder) joins the main pancreatic duct to form a single combined duct, the hepato-pancreatic duct, before it opens into the duodenum.

Step 2. Identify the sphincter: the sphincter of Oddi specifically guards this combined hepato-pancreatic duct's opening into the duodenum, controlling the release of both bile and pancreatic juice together. …

Trace the duct pathway from liver/pancreas to duodenum and identify exactly which comb …

• Confusing the sphincter of Oddi with a sphincter on the common bile duct alone, before it merges with the pancreatic duct. …