--- module: 078-03 language: en chapter: 78 title: "Abdominal Anatomy, Peritoneum, Viscera, and Portal Circulation" module_title: "Liver, biliary tree, pancreas, spleen, retroperitoneum, vessels, and lymphatics" source_sha256: 1f2db26b7130c3b55e64813b49b4fef4d6aa157181607884f27286ac0ee7f63c --- # Upper abdominal organs, vessels, and lymphatics ## Liver form and attachments ### Mainly beneath right diaphragm, extends left ### Anatomical lobes split by falciform ligament ### Functional plane near middle hepatic vein #### Gallbladder fossa to inferior vena cava ### Couinaud segments are independent portal territories #### Portal pedicle central, hepatic veins between #### Caudate drains directly to cava ### Bare area, porta, gallbladder bed uncovered ### Hepatic veins and cava fix liver posteriorly ### Hepatoduodenal ligament arrangement #### Bile duct right anterior, artery left anterior #### Portal vein posterior, variants frequent ## Hepatic inflow and outflow ### Portal vein forms behind pancreatic neck #### Superior mesenteric and splenic veins join ### Proper hepatic artery from common hepatic ### Hepatic veins drain directly to cava ### Portal-systemic anastomoses #### Oesophagus, rectum, paraumbilical, retroperitoneal #### Portal hypertension enlarges collaterals #### Caput medusae not specific to portal disease ### Triad compression reduces inflow bleeding #### Hepatic-vein and caval bleeding persists ## Gallbladder and bile ducts ### Fundus, body, infundibulum, neck ### Fundus near right ninth costal cartilage ### Hepatic ducts form common hepatic duct ### Common bile duct behind first duodenum #### Joins pancreatic duct at hepatopancreatic ampulla ### Cystic artery in hepatocystic triangle #### Variants common, identify before division ### Stone site determines consequence #### Cystic duct: gallbladder inflammation #### Common bile duct: jaundice, cholangitis #### Ampulla: pancreatic drainage affected ### Diaphragmatic irritation refers to shoulder ## Pancreas ### Head in duodenal curve ### Uncinate process behind superior mesenteric vessels ### Tail in splenorenal ligament #### Vulnerable during splenic surgery ### Main duct joins bile duct ### Pancreas divisum alters pancreatitis risk ### Arcades to head, splenic branches to body, tail ### Pancreatitis spreads through retroperitoneal planes #### Lesser sac, mesentery, paracolic spaces ## Spleen ### Under left ribs nine to eleven ### Normal spleen not palpable ### Gastrosplenic ligament: short gastric vessels ### Splenorenal ligament: splenic vessels, pancreatic tail ### Segmental arteries with limited anastomosis ### Splenic vein behind pancreas joins mesenteric vein #### Isolated thrombosis gives gastric varices ### Rupture: bleeding and left-shoulder pain ### Accessory spleens matter after splenectomy ## Retroperitoneum and great vessels ### Between posterior peritoneum and transversalis fascia ### Aorta enters at T12, divides near L4 #### Coeliac, superior, inferior mesenteric unpaired ### Coeliac: left gastric, splenic, common hepatic ### Variant origins crucial before embolisation ### Cava forms near L5, crosses diaphragm at T8 ### Left gonadal, suprarenal veins to left renal #### Left renal vein crosses under superior mesenteric ### Retroperitoneal disease compresses before visible ## Autonomic and lymphatic pathways ### Splanchnic nerves synapse in prevertebral ganglia #### Postganglionic fibres follow arteries ### Plexus blocks trade relief for hypotension ### Pre-aortic nodes drain gut ### Lateral aortic nodes drain kidneys, gonads, wall ### Trunks feed cisterna chyli and thoracic duct ## Cross-sectional localisation ### Aorta left, cava right, kidneys posterolateral ### Portal confluence behind pancreatic neck ### Follow vessels to identify ambiguous organs ### Intraperitoneal fluid outlines viscera, fills recesses ### Retroperitoneal fluid tracks fascia and psoas ### Gas location marks perforation or infection ### Enhancement phase selects what is shown