Spiral valves of Heister are undulating folds or valves in the proximal mucosa of the cystic duct. The cystic duct attaches the gallbladder to the common bile duct.
The spiral valves of Heister are supported by underlying smooth muscle fibers. There is some uncertainty regarding the role of the folds. Historically, physicians believed that their function was to aid in the passage of bile to and from the gallbladder, as well as regulate the degree of gallbladder distension.
The presence of the spiral folds, in combination with the tortuosity of the cystic duct, makes endoscopic cannulation and catheterization of the cystic duct extremely difficult. Also, the valves of Heister impede the introduction of surgical instruments and are susceptible to lacerations. They were named after German anatomist Lorenz Heister (1683-1758).