Classification of anatomical morphology of cystic duct and its association with gallstone

Figure 3 The classification of the morphology of cystic duct and model diagram. A: Type I: Linear, cystic duct (CD) (white arrow) straight into extrahepatic bile duct (EHBD) with no tortuosity; B: Type II: n-shaped, CD (white arrow) has a bend in the shape of an n; C: Type III: S-shaped, CD (white arrow) converges in an S-shape into the EHBD; D: Type IV: W-shaped, CD (white arrow) converges into the EHBD in a W-shape; E: Type I: Linear; F: Type II: n-shaped; G: Type III: S-shaped; H: Type IV: W-shaped.