Final answer:
In an ERCP examination, contrast medium is injected into the ducts of the gallbladder, liver, and pancreas to visualize them on an X-ray for diagnostic and treatment purposes.
Step-by-step explanation:
During an endoscopic retrograde cholangiopancreatography (ERCP) examination, the contrast medium is injected into the ducts of the gallbladder, pancreas, and liver. Specifically, it is used to help visualize the structure of the common bile duct, other bile ducts, and the pancreatic duct on an X-ray. This procedure involves the placement of a tube down the throat, into the stomach, and then into the small intestine where the dye is injected. The ERCP is used to diagnose and treat conditions such as gallstones blocking the bile ducts, pancreatitis, and complications from previous gallbladder surgery.