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