"The cystic veins begin as venules running over the surface of the fundus and body of the gallbladder merging proximate to the neck of the gallbladder, forming one or two main cystic veins. These are usually small (~1 mm calibre) veins that run alongside the cystic duct, and at right angles to the common bile duct. The cystic veins then drain into the portal venous system, most commonly into the right portal vein 1,3,5,6."
"The cystic veins (TA: venae cysticae) are one of two venous drainage pathways of the gallbladder. They subsequently drain into the portal vein."