Pete's Library

CONCISE SUMMARY FROM GROK:

Here is a concise 400-word summary (word count: 398) on gallbladder anatomy, structured for clarity and completeness.

Introduction and Location

The gallbladder is a pear-shaped, intraperitoneal sac that stores and concentrates bile produced by the liver. It measures 7–10 cm in length, 3–5 cm in width, with a normal capacity of 30–50 ml (up to 300 ml when obstructed). It lies in the gallbladder fossa on the visceral surface of the liver, between the right lobe and quadrate lobe (segments IV and V), in the right hypochondrium. The fundus projects anteriorly, often contacting the anterior abdominal wall at the 9th costal cartilage tip (Murphy’s point).

Gross Anatomy and Parts

• Fundus: Rounded, distal, widest portion; protrudes beyond the liver’s inferior border.

• Body: Main central portion; lies in the fossa.

• Infundibulum/Neck: Tapers proximally; neck connects to the cystic duct. Hartmann’s pouch is an outpouching at the infundibulum (common site for gallstones). Spiral valves of Heister in the cystic duct and neck regulate bile flow.

Relations: Superiorly – liver; inferiorly – duodenum (first part), transverse colon, hepatic flexure; posteriorly – porta hepatis structures.

Peritoneal Attachments and Calot’s Triangle

The gallbladder has a peritoneal-covered inferior surface and a bare superior surface adherent to the liver (covered by Glisson’s capsule extension). It connects via the cystic duct to the biliary tree, forming the common bile duct with the common hepatic duct.

Calot’s triangle (cystohepatic triangle) is surgically critical: bounded by the cystic duct (right), common hepatic duct (left), and inferior liver border (superior). Contents include the cystic artery, cystic lymph node (of Lund), and lymphatics. Careful dissection here prevents bile duct injury during cholecystectomy.

Blood Supply, Drainage, and Innervation

• Arterial: Primarily the cystic artery, a branch of the right hepatic artery (from common hepatic → celiac trunk). It divides into superficial and deep branches.

• Venous: Cystic veins drain the neck directly into the portal vein; fundus/body veins enter hepatic sinusoids.

• Lymphatic: To cystic node → porta hepatis nodes → celiac nodes.

• Nerve: Sympathetic (celiac plexus) and parasympathetic (vagus via hepatic branch) control contraction and relaxation.

Histology

The wall has three layers:

• Mucosa: Tall columnar epithelium with microvilli (for water/electrolyte absorption); lamina propria with folds/rugae. Rokitansky-Aschoff sinuses (mucosal outpouchings into/through muscularis) are normal but prominent in adenomyomatosis or inflammation.

• Muscularis propria: Smooth muscle (circular, longitudinal, oblique fibers); no distinct submucosa or muscularis mucosae.

• Serosa/Adventitia: Peritoneum on free surface; connective tissue on hepatic surface.

Functions and Clinical Relevance

The gallbladder concentrates bile (absorbs water/ions), stores it, and releases it via cholecystokinin (CCK)-induced contraction in response to fatty meals, aiding fat emulsification and digestion.

Variations: Phrygian cap, duplication, agenesis, ectopic position, or elongated fundus. These matter in imaging and surgery.

Clinical Notes: Common site for gallstones (cholelithiasis), leading to acute/chronic cholecystitis, biliary colic, or complications like choledocholithiasis. Laparoscopic cholecystectomy requires precise Calot’s triangle identification. Post-cholecystectomy, bile flows directly from liver to duodenum; most patients adapt well, though some experience bile acid diarrhea.

This overview integrates gross, microscopic, vascular, and functional aspects with surgical implications for thorough understanding. Variations and Calot’s triangle highlight the need for anatomical awareness in clinical practice.