Choledochal cysts are cystic enlargements of the bile ducts, which do not occur commonly.

Anatomy and Physiology

• The gall bladder is a small pear shaped organ located beneath the liver in the right side of the upper abdomen
  
• The cystic duct carries bile from the gallbladder and joins the common hepatic duct, which carries bile from the liver) to form the common bile duct. The common bile duct then empties into the duodenum, which is the beginning of the small intestine (Figure 1)
  
• The main purpose of the gallbladder is to concentrate and store bile. It releases bile by ejecting it through the common bile duct into the small intestine when fatty foods are eaten. The bile aids in the digestion of fatty foods.
  
• The gall bladder may be congenitally absent

Figure 1 - Anatomy of the liver, duodenum, gallbladder, hepatic ducts and common bile duct. © R. Walls