The common bile duct is opened here to reveal several small calculi within the lumen, indicative of choledocholithiasis. Note that the gallbladder to the right is dilated from obstruction at its neck from an impacted gallstone. Stones from the gallbladder, if small enough, can pass through (or impact within) the neck of the gallbladder and/or gain access to the common bile duct, a condition then known as choledocholithiasis.