General characteristics and topography of the gallbladder
The gallbladder (vesica fellea) is a pear-shaped musculomembranous sac located in the corresponding fossa (fossa vesicae felleae) on the visceral surface of the liver. The main function of the organ is the storage and concentration of bile coming from the liver.
The topography of the organ is described by three classical parameters:
- Holotopy: its projection onto the anterior abdominal wall falls in the right hypochondriac and epigastric (epigastrica) regions.
- Skeletotopy: the fundus of the gallbladder is projected at the angle formed by the lateral margin of the musculus rectus abdominis on the right and the costal margin.
- Syntopy: superiorly and anteriorly, it is adjacent to the liver; to the left, to the pylorus of the stomach (pylorus); to the right, to the right colic flexure (flexura coli dextra); the fundus emerges from beneath the anteroinferior margin of the liver and contacts the anterior abdominal wall.
Peritoneal relations and parts of the organ
Most commonly, the gallbladder is covered by peritoneum mesoperitoneally (on three sides), since one of its surfaces is adjacent to the liver. Variants are possible: with deep embedding into the parenchyma, an extraperitoneal position; when separated from the liver, an intraperitoneal position with the formation of its own mesentery.
Anatomically, the organ is divided into:
- Fundus — fundus vesicae felleae;
- Body — corpus vesicae felleae, the widest part;
- Neck — collum vesicae felleae, transitioning into the cystic duct.
The length of the gallbladder is 8–14 cm, width 3–5 cm, capacity 60–100 ml. In the region where the neck transitions into the cystic duct, there is a characteristic wall protrusion — Hartmann's pouch.
Wall structure
The wall of the gallbladder is formed by four layers (from inside out):
- Mucous membrane (tunica mucosa) — forms numerous spiral folds, lined with simple columnar epithelium with pronounced resorptive capacity;
- Muscular layer (tunica muscularis) — consists of longitudinal and circular bundles of smooth muscle fibers;
- Subserous layer (tela subserosa);
- Serous membrane (tunica serosa) — covers the surfaces facing the abdominal cavity.
Blood supply, venous and lymphatic drainage
Arterial blood supply is provided by the cystic artery (arteria cystica), which typically arises from the right branch of the arteria hepatica propria. Venous drainage occurs via the corresponding vena cystica, which drains into the portal vein (vena portae hepatis).
The topography of the cystic artery is of fundamental surgical importance during cholecystectomy: for safe ligation of the vessel, the surgeon uses Calot's triangle as a landmark, the boundaries of which are:
- superiorly — the cystic artery;
- to the right — the cystic duct (ductus cysticus);
- to the left — the common hepatic duct (ductus hepaticus communis).
Lymph drains into regional nodes located near the neck of the gallbladder and close to the duodenum. During inflammation, these nodes enlarge and can compress the bile ducts, causing cholestasis.
Extrahepatic bile ducts
The right and left hepatic ducts emerge from the right and left lobes of the liver, respectively (ductus hepaticus dexter and ductus hepaticus sinister), and merge to form the common hepatic duct (ductus hepaticus communis). After joining the cystic duct (ductus cysticus), it forms the common bile duct — ductus choledochus. This is the largest duct of the system: diameter 6–8 mm, length about 8 cm.
Topographically, four parts are distinguished in the ductus choledochus:
- pars supraduodenalis — above the superior part of the duodenum;
- pars retroduodenalis — behind its superior horizontal part;
- pars pancreatica — within the thickness of the head of the pancreas;
- pars duodenalis (intramural) — in the wall of the duodenum.
The passage of the duct through the pancreatic parenchyma explains the impairment of bile outflow in pancreatitis.
Opening into the duodenum and the sphincter apparatus
In the intramural segment, the common bile duct joins the pancreatic duct (ductus pancreaticus), forming the hepatopancreatic ampulla (ampulla hepatopancreatica). The ampulla opens at the apex of the major duodenal papilla (papilla duodeni major, Vater's papilla), located on the medial wall of the descending part of the duodenum.
In the region of the terminal part of the ducts, the muscle layer thickens and forms the sphincter of the hepatopancreatic ampulla, or the sphincter of Oddi, which regulates the flow of bile and pancreatic juice into the duodenum.
Path of bile: from the hepatic ducts, it enters the common hepatic duct; when the gallbladder is full, it is directed through the ductus choledochus into the intestine; when empty, it is stored in the gallbladder via the ductus cysticus; upon gallbladder contraction, bile returns along the same path and is secreted into the intestinal lumen through the ampulla.
Key points
- The gallbladder (vesica fellea) lies in the corresponding fossa on the visceral surface of the liver and is usually covered by peritoneum mesoperitoneally.
- The organ is divided into the fundus, body, and neck; Hartmann's pouch is located in the region of the neck.
- The wall consists of mucosal, muscular, subserous, and serous layers; the mucosa forms spiral folds.
- Blood supply — arteria cystica from the right branch of the hepatic artery; venous drainage — into the portal vein.
- Calot's triangle is a key landmark during cholecystectomy; its boundaries are: arteria cystica, ductus cysticus, ductus hepaticus communis.
- The confluence of the common hepatic and cystic ducts forms the ductus choledochus, which is about 8 cm long.
- The common bile duct has four parts: supraduodenalis, retroduodenalis, pancreatica, duodenalis.
- Bile and pancreatic juice enter the duodenum via the ampulla of Vater, regulated by the sphincter of Oddi.