Liver Diseases

13 Liver Diseases



Anatomy of the Liver



image

Liver in Situ


image

Surfaces and Bed of Liver



Basic Gross Anatomy



• Liver develops in ventral mesogastrium, surrounded by peritoneum, except for bare area bounded by
image Coronary ligament: peritoneal attachment to the inferior diaphragm

image Left and right triangular ligaments, where coronary ligament reflects posteriorly

• Falciform ligament: remnant of ventral mesogastrium attaching to the abdominal wall

• Round ligament
image Remnant of umbilical vein within the falciform ligament

image Persisting venous connections may be present between liver/portal system and body wall.

• Hepatoduodenal ligament: peritoneal fold surrounding portal triad (hepatic artery proper, portal vein, bile duct), right edge of lesser omentum

• Omental foramen (of Winslow): posterior to hepatoduodenal ligament, opens into lesser (peritoneal) sac

• Lesser omentum (hepatogastric ligament) and posterior aspect of stomach form anterior wall of lesser (peritoneal) sac


Divisions



image

Liver Segments and Lobes


• Right and left hepatic lobes: divided by a plane extending from cystic fossa (anteroinferior) through inferior vena cava (superoposterior)

• Right lobe typically contains 50%-70% of total liver volume.
image This is different from the historical view, dividing lobes by the falciform ligament.

• Each hemiliver contains its own hepatic artery branch, portal blood supply, venous drainage, and bile duct.
image Basis for dividing the lobes without total vascular inflow occlusion

• Further division into 8 segments, resectable based on blood vessel and bile duct anatomy
image Segment I: posterior, right and left caudate lobe

image Segment II: left lateral division, left portal lobe, lateral segment (lateral superior)

image Segment III: left lateral division, left portal lobe, left lateral anterior segment (lateral inferior area)

image Segment IV: medial division, left portal lobe, medial segment (medial inferior area, quadrate lobe)

image Segment V: right medial division, right portal lobe, left anterior medial segment (anterior inferior area)

image Segment VI: right lateral division, right portal lobe, lateral segment (posterior inferior)

image Segment VII: right lateral division, right portal lobe, posterior lateral segment (posterior superior)

image Segment VIII: right medial division, right portal lobe, posterior medial segment (anterior superior area)


Portal Triads and Bile Duct System



image

Liver Vessel and Duct Distribution


• Portal triads—hepatic artery, bile duct, and portal vein branches—and lymphatics seen in characteristic relationships from microscopic (lobular) to macroscopic (lobar) levels

• Popular functional concepts of liver parenchyma include classic lobules and liver acini organized around vessels.

• Interlobular portal vein branches travel in interlobular septum on periphery of hepatic lobules.

• Interlobular hepatic artery branches travel alongside portal veins in septa, providing smaller branches to ducts and parenchyma (hepatocytes) of lobules.

• Interlobular bile duct branches receive bile canaliculi draining lobular parenchyma.

• Central veins in the middle of lobules drain into hepatic vein tributaries.

• Sinusoids are formed by plates of hepatocytes surrounding lobular central veins.

image

Liver Structure Schema



Innervation of the Liver



• Visceromotor control of human liver parenchyma and intralobular biliary ductules
image Incompletely understood

image Efferents involved in regulation of portal blood flow, bile flow, regeneration of parenchyma, metabolism of lipids, carbohydrates, and plasma proteins

• Hepatic plexus (around the hepatic artery proper) is largest branch of celiac plexus.

• Parasympathetic: vagus
image Preganglionic fibers from anterior and posterior vagal trunks distributed via celiac plexus to intrahepatic ganglion cells

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Aug 12, 2016 | Posted by in ANATOMY | Comments Off on Liver Diseases

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