Liver and Biliary Tree
The gallbladder (GB) is often described as pear shaped and 7-10 cm long. It lies on the visceral surface of the liver adjacent to segments IV and V. It is described as having the following three parts:
- Fundus – The fundus of the GB is covered with peritoneum and this also binds its body and neck to the liver. Connective tissue attaches it to the fibrous capsule of the liver on its hepatic surface.
- Neck – opens into the cystic duct
The GB is related inferiority to the transverse colon and duodenum. Sometimes, an inflamed GB may ulcerated into either of these structures. It is also a complication of GB surgery!
Hartmann’s pouch is an out-pouching of the GB wall at the junction of the neck and the cystic duct. It is an important surgical landmark in biliary surgery and is usually almost always described in an inflamed, dilated and pathological GB. This is where gallstones may be lodged.
The mucosa of the neck spirals into a fold described as the spiral valve. This keeps the cystic duct open to allow bile to flow into the GB when normal physiological mechanisms close the distal end of the biliary tree
The cystohepatic (Calot’s) triangle
The cystohepatic (Calot’s) triangle is important in surgical dissection during cholecystectomy. Clinically this is described as a triangle bounded by the cystic duct, the hepatic duct and the underside of the liver (although the original description by Calot was of the cystic duct, the hepatic duct and the hepatic artery).
Relationships of the Gallbladder
The relationships of the gallbladder are listed below:
- The visceral surface of the liver
- The fundus is related to the anterior abdominal wall at the level of the tip of the ninth right costal cartilage
- The neck: The lesser omentum
- The body: The first and second parts of the duodenum
- Inferiorly: The fundus/body: the transverse colon
Blood and Nervous Supply of the Gallbladder
The gallbladder is supplied by the cystic artery, a branch of the right hepatic artery and also by branches directly from the liver. There is no accompanying cystic vein with the cystic artery. Small veins drain the gallbladder directly into the liver.
The draining lymph vessels pass to a cystic lymph node situated near the neck of the gallbladder.
The cystic node then drains along the hepatic nodes along the course of the hepatic artery to the celiac plexus.
The nerves to the gallbladder are derived from the celiac plexus (sympathetic innervation), vagus nerve (parasympathetic innervation) and the phrenic nerve (sensory fibres).
The fundus of the gallbladder may be folded back on itself. This is described as the Phrygian cap. The name comes from the type of hat worn by slaves in ancient Greece.
The gallbladder may contain a simple septation or diverticula.
The location of the gallbladder can be variable and can be located in the following positions:
The gallbladder can herniate through the foramen of Winslow into the lesser sac. Rarely, the gallbladder maybe absent (0.05%) and can be associated with other congenital abnormalities.
A double gallbladder can occur in rare cases (0.025%), and if present, they usually share the cystic duct.