dms week 4 liver
porta hepatis
"doorway to liver" • Fissure through which the portal vein and hepatic artery enter the liver and the common bile duct exits the liver
falciform ligament
(external surface) extrahepatic part of the ligamentum teres; separates right lobe from left lobe at diaphragmatic surface
reidel's lobe
- Anatomical variant where the inferior aspect of the right lobe extends as far as the iliac crest - Tongue-like extension - More common in females
papillary process
- Anteromedial extension of the caudate lobe - May appear separate from the liver - May mimic lymphadenopathy
hepatic veins
Best seen in transverse scans at the cephalic portion (dome) of the liver • Three: Right, Middle and Left • Middle and left join together prior to draining into IVC • All three drain into the IVC and the IVC drains the liver
portal triad
Contains portal veins, hepatic arteries, and bile ducts go thrught liver together
right lobe
Divided into anterior and posterior segments by a short right intersegmental fissure
Glisson's capsule
Enclosed by a fibrous capsule known as
kupffer cells
defense against invading organisms
fissure for ligamentum venosum
divides left lobe anteriorly from caudate lobe posteriorly
left portal vein
divides left lobe anteriorly from caudate lobe posteriorly
Couinaud Intersegmental Anatomy
divides the liver into 8 segments, surgeons use this system in order to safely resect only the particular segment that involves pathology
IVC
divides the liver into left and right lobes
right margin
extends as a projection (the caudate process) between the IVC and the portal vein
left margin
forms the hepatic boundary of the superior recess of the lesser sac
quadrate lobe
its medial segment of left lobe
Bare area
lies to the right of the IVC in direct contact with the diaphragm (not covered by peritoneum)
Gallbladder
lives within the main lobar fissure also divides the liver into left and right
left hepatic veins
located within the left intersegmental fissure and divides left lobe into medial and lateral segments
middle hepatic vein
located within the main lobar fissure and divides liver into right and left lobes
middle hepatic veins
located within the main lobar fissure and divides liver into right and left lobes
right hepatic veins
located within the right intersegmental fissure and divides right lobe into anterior and posterior segments
Bile ducts and portal veins
normally travel parallel to each other. If both are seen on ultrasound, this is referred to as the parallel channel sign (AKA double barrel sign, shotgun sign)
left lobe
o Divided into medial and lateral segments o Divided cranially to caudally by: Left hepatic vein Left portal vein (ascending, vertical segment) Ligamentum teres
Interlobar or Main Lobar Fissure
o Divides right and left lobes o Appears sonographically as a thin echogenic line running from the right portal vein to the gall bladder fossa on a sagittal scan o Extends from gall bladder to IVC on transverse scan
main lobar fissure
o Divides right and left lobes o Appears sonographically as a thin echogenic line running from the right portal vein to the gallbladder fossa on a sagittal scan o Extends from gallbladder to IVC on transverse scan
left intersegmental fissure
o Divides the left lobe into medial and lateral segments
right intersegmental fissure
o Divides the right lobe into anterior and posterior segments
falciform ligament
o Extrahepatic part of the ligamentum teres only seen with ascites o Connects liver to the anterior abdominal wall
ligamentum venosum
o Remnant of the fetal ductal venosum o Separates the left lobe anteriorly from the caudate lobe posteriorly o Defines left lobe from caudate lobe o Ligamentum teres and ligamentum venosum communicate at the region of the portal vein
ligmentum teres
o Remnant of the fetal umbilical vein (closes after birth) o Extension of left portal vein o Divides the medial from lateral segment of the left lobe o Umbilical vein becomes recanalized with cirrhosis or portal hypertension (patent umbilical vein) o Appears sonographically as an echogenic spot (triangular) on the transverse scan in the left lobe; not to be mistaken for pathology (hemangioma)
valsalva maneuver
taking a deep breath and pushing it out of rectum
right portal veins
travels transversely into the right lobe - Branches into anterior and posterior branches
left portal veins
travels vertically into left lobe - Branches into medial and lateral branches
hepatic arteries
• Bring oxygenated blood into the liver • Common hepatic artery branches off the celiac axis • Gives rise to gastroduodenal artery, supraduodenal artery, and right gastric artery • Common hepatic artery divides into right and left branches which supply the right and left lobes, respectively
portal veins
• Brings nutrient rich blood from the intestines into the liver • Main portal vein originates at the union of the splenic vein and superior mesenteric vein (portal splenic confluence) where something meets
