Biliary-type pain followed by obstructive jaundice (pale offensive stools, dark frothy urine) in a patient with multiple small gallbladder stones means a stone has migrated into the common bile duct (secondary CBD stone = choledocholithiasis, the commonest cause of obstructive jaundice).

• A stone that stays in the gallbladder (or cystic duct) does not block bile flow to the gut, so it does not cause jaundice.
• Small stones pass downstream into the CBD; they do not lodge in the intrahepatic or common hepatic ducts.