Initial exploration is best performed with choledochoscopy. However if unavailable, the following technique provides reproducible results. The duct is held open and explored with a metal probe, such as Bakes dilator, which is directed downward to Vater's papilla and into the duodenum if possible. The patency of the papilla is determined at this time. With a finger inserted into the foramen of Winslow to give counter-resistance as the metal probe passes, a grating of metal against stone may be sensed, and a calculus may be found that otherwise might be overlooked. If a probe passes into the duodenum, it does not ensure that a calculus either is not impinged at the ampulla of the common duct or is not resting in a sacculation of the duct. A small, pliant metal scoop, such as a Cushing pituitary curet, is then repeatedly directed into the region of the papilla of the common bile duct, and any stones are removed (Figure 5). A scoop, 8 by 15 mm, with an easily molded handle is entirely adequate; large scoops with rigid handles should not be used. If a stone is impacted in a diverticulum to one side of the ampulla of the bile duct, the left forefinger and thumb may fix the stone so that it is fragmented by the scoop and can be removed piecemeal or by irrigation. The scoop is directed upward into both hepatic ducts, for small calculi may lodge in the larger intrahepatic bile ducts (Figure 1). A stone forceps may be used. Also, a Fogarty balloon catheter may be useful in extracting stones and verifying patency of the ampulla. After stone removal, a rubber catheter, No. 8 or 10 French, is inserted toward the liver, and warm saline is injected as the catheter is withdrawn. The catheter is then directed downward. A sudden increase in resistance will be encountered when it passes through Vater's papilla into the duodenum (Figure 6). Saline is gently injected, and if the tip of the catheter is in the duodenum, the duodenum will balloon out (Figure 7). Additional palpation of this area is facilitated by mobilizing the second portion of the duodenum (see Kocher maneuver, Plate 99, Figure 12). The scooping is then repeated. Once its patency has been established, no attempt is made to dilate the papilla beyond the gentle passage of a No. 12 or 14 French catheter, which can be felt clearly within the duodenum. Some prefer to inspect the lumen of the common duct with a flexible choledochoscope.