Liver A & P Flashcards
What are the three lobes of the liver?
right, left, and caudate
T/F - In the event of caudate lobe enlargement, the IVC may be compressed.
true
The caudate lobe is located:
_______ to the ligamentum venosum; _______to the porta hepatis; _______ and _______ to the IVC; _____ to the lesser sac.
posterior, posterior, anterior and medial, lateral
Caudate lobe receives branches from the ____ and _____ portal veins and its venous drainage is directly into the IVC via the small _______ veins.
right and left, emissary veins
List the 8 segments of the liver.
I caudate II left lateral superior III left lateral inferior IVa left medial superior IVb left medial inferior V right anterior inferior VI right posterio inferior VII right posterior superior VIII right anterior superior
The hepatic veins are ________, while the vessels of the portal triad are _______ and encased by a fibrofatty sheath known as _______ _______.
intersegmental, intrasegmental, Glisson’s capsule
What divides the right and left hepatic lobes?
main lobar fissure
What divides the anterior segment of the right lobe from the medial segment of the left lobe?
main lobar fissure
The _____ is identified between the GB neck and the junction of the right and left ______ veins.
MLF, portal
The RHV divides the right lobe into ______ and _______ segments, aka right intersegmental fissure.
anterior, posterior
The _____ is identified between the GB neck and the junction of the right and left ______ veins.
MLF, portal
What are the 4 landmarks for the left intersegmental fissure?
LHV, ascending LPV, falciform ligament, ligamentum teres
Ligamentum venosum is a remnant of the _____ ______.
ductus venosus
What separates the left lobe from the caudate lobe?
ligamentum venosum
What are the 3 landmarks for the MLF?
GB (inferior end of MLF), IVC, MHV
________ _______ runs from the LPV to the IVC seperating the left lobe from the caudate lobe.
ligamentum venosum
What is the name of the remnant of the umbilical vein that runs from the umbilicus to the LPV? Shortly after birth, the umbilical vein contracts down to form this.
ligamentum teres
With portal HTN, the _______ ______ recanlizes to form a portosystemic venous collateral.
ligamentum teres recanalizes in cirrhosis to function as a venous collateral
Describe direction of fetal circulation, starting at the liver.
umbilical vein (lig teres) - LPV - ductus venosus (lig venosum) - IVC
Why doesn’t the liver really infarct?
Because it has two sources of blood and would have to thrombose both to infarct.
Hepatopetal
flow toward the liver, “seeking”, “pedaling in”
Hepatfugal
flow away from the liver, “fleeing”
Upper limits measurement for the portal vein diameter.
13mm, anything larger suggests portal HTN
What are the two sources of blood flow to the liver, what percentage of flow do they each bring, and how much in total per minute?
portal vein (75%), proper hepatic artery (25%), 1500 mL/min
What is the hepatic oxygenation breakdown between the two inflow vessels?
50% PHA and 50% PV, PV bigger but equally give oxygen
Describe normal portal vein flow and what can happen with breathing after eating.
Usually low-velocity continuous flow with mild undulations in a healthy subject, monophasic. Increases and decreases with breathing. Flow velocity can increase after eating.
The ______ _______ is the functional separation of the RT and LT lobes of the liver.
portal system
Caudate lobe is located on the _____-______ surface of the liver, between the IVC and medial left lobe of the liver.
posterior-superior
Imaging the liver, when angling superior and transversely, what segments are visualized?
7, 8, 4a and 2
Imaging the liver, when angling inferior and transversely, what segments are visualized?
6,5,4b and 3
List the respective segments for left lateral, left medial, right anterior, and right posterior sectors.
Left lateral - II and III
Left medial - IVa and IV b
Right anterior - V and VIII
Right posterior - VI and VII
Describe normal hepatic vein waveforms.
triphasic (reflecting right atrial filling, contraction, and relaxation), phases above and below baseline, pulsatile
The proper hepatic artery runs parallel to the MPV and is located ______ and to the ____ of the MPV.
anterior, left
T/F - The RHA and LHA typically arise from the proper hepatic artery in approx 55% of patients.
True
Replaced RHA may originate from the SMA in approx ______ % of patients. It would be seen posterior to the head of the pancreas and MPV.
11%
Replaced LHA may originate from the left _____ artery in approx 10% of patients.
gastric
Describe normal hepatic artery waveforms.
Low-resistance (flow through diastole), parabolic, turbulent with spectral broadening
Describe hepatic artery waveform that suggests transplant rejection.
high-resistance suggests more commonly venous congestion or possible organ rejection
What is the significance of a post-operative hepatic liver transplant with parvus tardus hepatic artery waveform?
suggests proximal anastomotic stenosis (>50%)
Hepatic ligaments (5)
lig. teres, falciform lig., coronary lig, right and left triangular ligs
_______ ________ is a peritoneal reflection or fold created by the passage of the embryonic umbilical vein from the umbilicus to the left branch of the portal vein.
Falciform lig, may see suspended with ascites surrouding
What peritoneal reflections suspend the liver from the diaphragm and surroud the bare area of liver?
Coronary lig
Liver area that is in direct contact with the diaphragm, is not part of the peritoneal space, and does not accumulate ascites.
Bare area
What are the peritoneal reflections to the far right and left of the bare area?
RT and LT triangular lig
Liver size will vary with height, weight, and body surface area. Hepatomegaly is indicated in 75% of patients with a > than _____cm superior-inferior dimension.
15.5cm
What is Riedel’s lobe?
inferior projection of the RT lobe commonly seen in women and may be mistaken for hepatomegaly (Tip: if LT lobe is small and RT lobe is big, likely Riedel’s lobe)
Describe liver echogenicity.
homogeneous and slightly hyperechoic compared to the normal renal cortex
Hyperechoic
echoes greater than
Hypoechoic
echoes less than
Isoechoic
echoes equal
Anechoic
without echoes
Sonolucent
without echoes
Put in order of decreasing echogenicity (Spleen/Liver, Pancreas, Renal Sinus, Renal Cortex)
renal sinus>pancreas>spleen/liver>renal cortex
