Normal Anatomy of the Liver and Pancreas

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Normal anatomy of the liver
Diaphragmatic surface of the liver
is dome-shaped, follows the contours of the diaphragm,
reaches forward as far as the inferior edge of the liver
Inferior margin of the liver
its major landmark is the sagittal groove, a deep notch for the
ligamentum teres which runs in the free edge of the falciform ligament
Incisura ligamenti teretis
margo inferior
Incisura vesicae fellae
Inferior margin of the liver
T2 BLADE
Visceral surface of the liver
Porta hepatis – a central depression for the passage of the portal vein, hepatic artery and common bile duct
Anterior to this is the gallbladder fossa with the quadrate lobe to its left
Posteriorly the caudate lobe separates the porta from IVC
Several shallow impressions relate to the shape of adjacent organs
Visceral surface of the liver
External lobation of the liver
The H-shaped indentations on the
visceral faces of the liver divide it
into four lobes: the right, left,
quadrate and caudate lobes.
The right-hand limb of the H is
formed by the gallbladder fossa
anteriorly and by the IVC sulcus
posteriorly
The left limb of the H is formed by
anteriorly – the deep fissure for the
ligamentum teres and posteriorly by
the fissure for the ligamentum
venosum
*
**
Segmental liver anatomy
Segmental liver anatomy.
The segmental anatomy of
the liver as described by
Couinaud and Bismuth.
Each anatomic segment
receives a unique portal
pedicle (dark gray)
consisting of a portal
venous branch, hepatic
arterial inflow, and bile
duct.
Individual segments are
drained by unique hepatic
venous outflow branches
(light gray) and separated
by connective tissue
scissurae.
Segmental liver anatomy
Couinaud divided the liver into a functional left and right liver by a main portal
scissurae containing the middle hepatic vein. This is known as Cantlie's line.
Cantlie's line runs from the middle of the gallbladder fossa anteriorly to the inferior
vena cava posteriorly.
• Portal vein – superior nad
inferior segments
• Right hepatic vein – anterior
and posterior segments of RL
(5,6,7,8)
• Middle hepatic vein – Cantlie’s
line
• Left hepatic vein – medial and
lateral segments of LL (4,2,3)
There are eight liver segments.
Segment 4 is sometimes divided into segment 4a and 4b according to Bismuth.
The numbering of the segments is in a clockwise manner (figure).
Segment 1 (caudate lobe) is located posteriorly. It is not visible on a frontal view.
Segmental liver anatomy - CT
2
7
8
3
4
6
5
Segmental liver anatomy
MRI
Segmental liver anatomy
US
2
7
8
4
6
5
3
Biliary tract anatomy
The right and left main hepatic ducts fuse at the hilum, anterior to the bifurcation of the portal
vein, to form the common hepatic duct. The main bile duct is divided into two segments: the
common hepatic duct and common bile duct, divided by the cystic duct insertion.
Biliary tract anatomy
The left hepatic duct drains 3 segmments of the left liver, and the right hepatic duct 4
segments of the right liver. The right hepatic duct arises from the union of two main sectorial
ducts: an anterior division draining segments 5 and 8 and a posterior division draining 6 and 7.
The caudate lobe (segment 1)
has a variable drainage pattern,
but in the majority (78%)
drainage is into both main ducts.
Biliary tract anatomy
The common bile duct passes inferiorly posterior to the first part of the duodenum
and pancreatic head. In the majority it then forms a short common channel with the
main pancreatic duct within the wall of the duodenum, termed the ampulla of Vater.
Biliary tract anatomy
The common bile duct
lenght - 5-15cm depending on the level of the cystic duct insertion
diameter - up to 6mm, in elderly 8mm, after cholecystectomy up to 10mm.
Biliary tract anatomy
Gallbladder - a bile reservoir, lies in the cystic fossa
The cystic duct - lenght 2-4cm, diameter 1-5mm, joins the common hepatic duct in
its supra duodenal segment, half the way between the liver hilum and ampulla of
Vater
US, CT- visible
in 50% of cases
MRCP- almost
always visible
Biliary tract anatomy
MRCP
Developmental anomalies of biliary tract anatomy
Developmental anomalies of biliary tract anatomy
Insertion of right posterior sectoral duct into left hepatic duct
Liver vascular supply
• portal supply
• arterial supply
• venous outflow
Liver vascular supply
Portal supply
The liver receives app. 2/3 of its blood supply from the portal vein.
Normally the superior mesenteric vein and splenic vein become confluent to form a single
portal vein, which courses to the hepatic hilum and divides into the right end left branch.
Portal vein lenght – 6-7cm, diameter 6-13mm.
Liver vascular supply
Venous outflow – three major hepatic veins drain into the IVC
The collateral vessels in portal hypertension.
AWV = abdominal wall vein,
GEV = gastroesophageal vein,
IMV = inferior mesenteric vein,
IVC = inferior vena cava,
LGV = left gastric vein,
LPV = left portal vein,
LRV = left renal vein,
MV = mesenteric vein,
PDV = pancreaticoduodenal vein,
PEV = paraesophageal vein,
PV = portal vein,
RPPV = retroperitoneal-paravertebral vein,
SMV = superior mesenteric vein,
SRV = splenorenal vein,
SV = splenic vein,
UV = umbilical vein.
Liver vascular supply
Arterial supply – hepatic artery proper – 20% of blood supply
The usual arterial arrangement is for the common hepatic artery to arise as one of the three major branches
of the coeliac trunk. After giving off the gastroduodenal artery , it continues as the main hepatic artery, which
in turns divides into the right and left hepatic arteries.
Liver vascular supply
Hepatic artery proper
Normal Anatomy of the Pancreas
The pancreas is a
retroperitoneal organ
and is positioned in
the anterior pararenal
space. It is posterior
to the stomach and
lesser sac and
anterior to the
abdominal aorta and
upper lumbar
vertebrae.
Normal Anatomy of the Pancreas
CT
Parenchymal phase
The normal pancreatic parenchyma has CT attenuation values in the range of 30-60
HU. Pancreatic attenuation decreases due to fatty infiltration which occurs normally
with aging.
Normal Anatomy of the Pancreas
neck
1- liver
2- head of the
pancreas
3- pancreatic body
4- Wirsung's duct
5- tail of the pancreas
6- superior
mesenteric artery
7- vena cava inferior
8- aorta
9- spine
10- gallbladder
The normal pancreas is of similar echogenicity to the liver.
Normal Anatomy of the Pancreas
Normal pancreatic duct
Normal Anatomy of the Pancreas
MRCP
Normal MRCP performed
during secretin stimulation
shows a slight and temporary
increase in the caliber and
signal intensity of the main
pancreatic duct in A (arrow)
and progressive and
complete duodenal filling
(arrowheads in B). Complete
filling of the Santorini duct
(arrowhead in A) is also seen.
Normal Retroperitoneal Anatomy
Anterior Renal Fascia Posterior Renal Fascia
Anterior Pararenal Space

Boundaries
– Anteriorly: post parietal peritoneum
– Posteriorly: ARF

Contents: Ascending and descending colon,
duodenum, pancreas

Continuous across midline, with root of small
bowel mesentery and inferiorly with perirenal,
posterior pararenal and prevesical spaces
Posterior Pararenal Space

Boundaries
– Anteriorly: PRF and lateral conal fascia
– Posteriorly: transverse fascia
– Limited by and parallels psoas m.
– Open laterally to flank and inferiorally to pelvis


Contents: Fat (no visceral organs)
Continuous (potentially) with each other via
properitoneal fat of anterior abdominal wall
Interfascial Retroperitoneal
Planes
 Retromesenteric - between anterior pararenal and
perinephric spaces contiguous across midline and
laterally with retrorenal and lateral conal space
 Retrorenal - between perinephric and posterior
pararenal spaces
 Lateral conal
• *
Combined fascial plane continues into pelvis
anterolateral to psoas m. allowing pathway to pelvis

*
Trifurcation of 3 planes - anterioposterior location is
variable
The Perirenal Space



Anterior and post renal fasciae
Extent: Superior, medial, lateral,
inferior
Contents
Extent of Perirenal Space




Superior - open to bare area of liver and
contiguous with mediastinum
Medial - above renal hila perirenal spaces
are separate, beginning at level of hila
there is communication
Lateral - ARF, PRF fuse to form lateral
conal fascia
Inferior - ARF & PRF converge blend about
8 cm below kidney
Contents of Perirenal Space

Kidney, proximal collecting system,
renal septa, adrenal gland

Renal vasculature and perirenal vessels

Lymphatics

Bridging septa
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