Download THE LIVER - Orange Coast College

THE LIVER
I. Introduction/General Information
A. Largest of viscera
1. ~ 2.5% body weight
2. Completely covered by
Glisson’s Capsule
3. Incomplete covering by
peritoneum
General Information, continued …
4. Measurements are ~
a. 21 – 23 cm transverse
b. 15 – 18 cm superior
to inferior
c. 10 – 13 cm anterior
to posterior
General Information, continued …
B. Location:
1. right hypochondrium
2. epigastrium
C. Mostly covered by
ribs
D. Contains numerous
vascular structures
II. Detailed Anatomy
A. Four lobes
1. Divisions based on
blood supply,
bile drainage
2. Anatomical lobes divided
by falciform ligament
Inferior View of the Liver
A
P
Detailed Anatomy, con’t…
3. Functional Lobes
a. right and left lobes
separated by
imaginary line
b. from fossa for GB 
IVC
Right and Left Functional Lobes of the Liver
Left
Lobe
Right
Lobe
Detailed Anatomy, continued …
B. Functional Divisions
1. Right lobe
with caudate process
2. Left lobe:
a. Caudate lobe
b. Quadrate lobe
Caudate
Process
Detailed Anatomy, continued …
C. Fissures:
1. Right sagittal (main)
2. Left sagittal (accessory)
3. Portal
4. Right oblique intersegmental
5. Lateral intersegmental
Fissures of the Liver

Main lobar fissure

Boundary
between R and L
lobes


L.S. on U/S: seen
as hyperechoic
line from PV to
neck of GB
Used to ID GB
when it is packed
with stones
Fissures of the Liver

Portal fissure



T.S. on U/S
Created by portal
veins (triads)
R. main PV is //
to anterior body
wall
Segments of the Liver

Hepatic segments





I = caudate lobe
II & III = superior and
inferior lateral
segments, L. lobe
IV = medial segment,
L. lobe
V & VI = caudal to
transverse plane
VII & VIII = cephalad
to transverse plane
I
Functional divisions, continued …
4. Fossae (Superficial)
a. IVC – posterior
b. Portal Vein – inferior
c. Gallbladder – inferior
Fossae, Inferior Surface of the Liver

Fossa for IVC

Fossa for
Portal Vein

Fossa for Gall
Bladder
Functional Divisions, continued …
5. Impressions (visceral surface):
produced by abdominal viscera
a.
b.
c.
d.
e.
f.
Gastric (fundus of stomach)
Renal (right kidney)
Adrenal (right adrenal gland)
Duodenal (bulb of duodenum)
Esophageal (esophagus)
Right and left colic (flexures of
the colon)
Visceral Impressions, continued …
P
•Esophageal
•Renal
•Gastric
•Adrenal
•Duodenal
•Right colic
•Left colic
L
R
A
Detailed Anatomy, continued …
D. Ligaments
1. Falciform (most superficial anteriorly)
a. Divides left lobe in two sections
1. anatomical left lobe
2. caudate & quadrate lobes
b. Two layers of peritoneum
c. Extends to umbilicus
Ligaments, continued …
2. Ligamentum teres hepatis
(fetal source??)
3. Ligamentum venosum
(fetal source??)
4. Right/Left Coronary Ligaments
Hepatic Ligaments

Falciform ligament




L. coronary ligament
L. triangular ligament
Ligamentum teres
hepatis
Ligamentum
venosum
Ligaments, continued …
5. Hepatophrenic & Hepatorenal
ligaments:
a. Subdivisions of right
coronary ligament
b. hepatophrenic (superior)
& hepatorenal (inferior)
c. Surround BARE AREA
Hepatic Ligaments, con’t…


Hepatophrenic
ligament
Hepatorenal
ligament
Bare Area
Detailed Anatomy, continued …
E.
Lesser Omentum
1. Sleeve-like structure
2. Connects lesser curvature of
stomach & bulb of duodenum to
inferior surface of liver
3. AKA: Gastrohepatic or
Hepatoduodenal ligament
Lesser Omentum, continued …
3. Attachment surrounds Porta Hepatis
4. Continues on each side of ligamentum
venosum
5. Extends to caudate & left lobes
on posterior surface of liver
Lesser Omentum

Lesser Omentum: (R) Anterior view,
(L) Inferior view
Detailed Anatomy, con’t…
E. Subphrenic Spaces
1. clinically important
2. common sites for abscesses
3. Between liver and diaphragm
Subphrenic Spaces, con’t…
4. Right superior posterior subphrenic
space
a. Boundaries:
- superior: right coronary ligament
- anterior: liver
- posterior: parietal peritoneum
covering diaphragm
b. Extends inferiorly to….
Subphrenic Spaces, continued …
5. Right posterior inferior subphrenic
space
a. Boundaries
- above: inferior surface of liver
- below: transverse colon &
mesocolon
b. Extends over right adrenal &
kidney
Subphrenic Spaces, continued …
c. AKA: Hepatorenal Pouch/Recess,
Morrison’s Pouch
d. Patient lying supine:
1. Lowest part of peritoneal
cavity is behind liver
2. Fluid, pus, etc. collects here
3. Can cause abscess formation
Subphrenic spaces, continued …
6.
Right superior anterior subphrenic
space
a. Boundaries:
- right side of falciform ligament
- upper layer of right coronary ligament
- underside of diaphragm
- superior surface of liver
b. Found when patient lying prone
Subphrenic spaces, continued …
7. Most sources of peritoneal
contamination are on the right
8. Right posterior & right inferior
spaces are most significant sites
9. Infection may spread via
diaphragmatic lymphatics
Detailed Anatomy, continued …
F. Porta Hepatis: contains the following
structures
1. Hepatic arteries
a. Usually two, sometimes one
b. Originate from common/proper
hepatic artery
c. Course is variable
Porta Hepatis, continued …
2. Portal vein (supplies 1100
ml/blood per minute)
a. Largest structure in porta
b. Formed by confluence of
mesenteric veins & splenic
vein
Porta Hepatis
Hepatic
Artery
Portal
Vein
Common
Bile Duct
Porta Hepatis, continued …
3.
Hepatic & cystic ducts
4.
Nerves:
a. Vagus X (parasympathetic)
b. Fibers from celiac ganglion
Porta Hepatis, continued …
4. Lymph nodes:
a. most hepatic lymph vessels end in
nodes around porta hepatis
b. From here, drain into celiac nodes
Porta Hepatis, continued …
c. Some vessels pass through
falciform ligament
1. through diaphragm
2. into mediastinal nodes
d. enlarged nodes may compress
portal vein or hepatic duct
Detailed Anatomy, continued …
G. Vascular Structures in Liver
1. Largest vessels are portal vein and IVC
a. Portal Vein:
1. appears on T.S. as tubular,
echolucent structure
2. courses horizontally from
porta hepatis
Detailed Anatomy, continued …
3. walls echogenic due to
structures in portal triad
b. Left Portal Vein:
1. has more variable course
2. May be difficult to trace on
transverse scans
Hepatic Vessels

IVC

Right Portal Vein

Left Portal Vein

Main Portal Vein
Vascular Structures, continued …
c. Right Portal Vein:
1. anatomical landmark
2. extends into right lobe
3. branches after porta hepatis
4. L.S. shows “dumbbell” or
circular structure with
echogenic “collar”
Computer-enhanced image of RPV, L.S.
Computer-enhanced 3-D image of RPV, L.S.
Vascular Structures, continued …
d. IVC:
1. To right of aorta
2. Appears to pass through liver
3. Diameter enlarges after
renal veins join (~L-1)
Computer-enhanced 3-D image of Hepatic Vessels
Vascular structures, continued …
2.
Hepatic Veins:
a. Tubular structures
b. Enlarge cephalad
c. In superior half of liver
d. Angles of hepatic vein
branches oriented toward IVC
e. Walls not echogenic
Hepatic Veins
R. Hepatic Vein
Middle Hepatic Vein
L. Hepatic Vein
Detailed Anatomy, continued …
A. Bile Ducts
1. No “normal” anatomy
2. If dilated:
a. Echogenic collar
b. Lobulated shape
c. Highly branched over short
distances
d. Converge toward porta hepatis
Anatomy of the Biliary System (yeah, right…)
P
L
R
A
III. Hepatic Masses
A. May be cystic, solid, or complex
B. Simple Cysts
1. solitary or multiple
2. sonolucent
3. well-defined margins
4. exhibit posterior acoustic enhancement
5. Congenital cysts may contain cellular
debris
Simple Cysts, Hepatic Masses, continued …
6. Polycysts: usually accompany cysts
of kidney, spleen, and/or pancreas
7. Appearance:
a. Wall is distinct, sharp
border, crisp edges
b. Shape: spherical
Hepatic Masses, continued …
C.
Complex Masses
1. With central necrosis: irregular walls
a. Associated with metastases from
rapidly-growing neoplasms
b. Blood supply can’t supply tumor
growth
c. Central part of mass becomes
necrotic
Complex Masses,Hepatic Masses, continued …
2. With cellular or inflammatory debris:
a. walls are irregular
b. Associated with hepatic abscess
c. Internal bacterial infection
3. Due to echinococcal disease:
a. Show irregular wall thickness
b. Parasitic bacteria in sheep feces
Complex Masses, continued …
4.Hematoma: ill-defined borders,
sonolucent-to-complex masses
a. Early: appears sonolucent
b. After clot forms, echogenic
c. Due to liver trauma
Hepatic Masses, continued …
D.
Solid Masses often represent
carcinomas
1. Hepatoma: primary liver cancer
a. Central necrosis may be present
b. Tumor thrombus may be detected
impinging on major veins
Solid Masses, Hepatic Masses, continued …
2. Metastatic Liver Disease
a. “Bull’s Eye” or “Target” pattern
[adenocarcinoma of GI Tract]
b. Adenocarcinomas from other
sources more echogenic
c. Sonolucent metastases from
lymphomas, sarcomas
more complex
IV. Parenchymal Disorders
A. Sonographic appearance: non-specific
1. Stroma = supportive connective
tissue
2. Parenychma = functional tissue
3. Most liver tissue is parenchyma
Parenchymal disorders, continued …
B. Cirrhosis: Most common
1. Due to hepatitis or alcoholism
2. Sonographic appearance:
a. Moderately echogenic
b. Liver denser than normal
c. Due to formation of scar tissue
Cirrhosis, Sonographic appearance, continued …
c. Peripheral intrahepatic
vessels indistinct
1. reduced blood supply
2. peripheral vessels
obscured by scar tissue
Cirrhosis, Sonographic appearance, continued …
d. Lobes may show reduced size:
1. right lobe is more affected
2. left lobe enlargement
a. compensation
b. decreased function
of right lobe
Cirrhosis, Sonographic appearance, continued …
e. As scar tissue develops, blood
flow is affected
1. Blood backs up
2. Spleen and splenic vein
enlarge
e. Portal Hypertension
Cirrhosis, Sonographic appearance, continued …
f. Liver margin:
1. indentations
2. changes in contour
3. blunted edges
4. may be observed on U/S
Cirrhosis, Sonographic appearance, continued …
g. Increased incidence of
hepatoma in advanced
cirrhosis
h. detection of ascites aids in
differential diagnosis
1. Ascites: fluid in
peritoneal cavity
2. Due to portal HTN
Parenchymal Disorders, continued …
C. Fatty Replacement (prior to
cirrhosis)
1. Appearance similar to cirrhosis
2. May be initial stage of cirrhosis
3. Difference:
a. Intrahepatic vessels remain
clearly defined
b. No portal HTN
V. Other Diseases and Conditions
A. Congestive Hepatomegaly:
1. Enlargement of liver secondary
to congestive heart failure
2. Homogeneous: liver rarely shows
echo changes
3. Tissue attenuation may
decrease as liver fills with blood
Other Disease Conditions, continued …
4. Marked dilation of IVC without
respiratory influence is proof of
right heart failure
5. Hepatic vein branches may show
enlargement
Other disease conditions, continued …
6. Thrombosis of IVC may show
similarities
-thrombus can be detected
7. Other signs:
a. Ascites
b. dilation of right atrium
Other diseases and conditions, continued …
B.
Liver Abscesses:
1. Commonly found in
hepatorenal pouch
2. Appear cystic with irregular
borders and fine precipitates
Other Disease Conditions, continued …
C. Obstructive Jaundice:
1. Result of obstruction of bile flow
2. Dilation of intrahepatic bile ducts
3. Ultrasound can differentiate
between obstructive and
hepatocellular jaundice
Dilated CBD: seen in Obstructive Jaundice
Other Disease Conditions, continued …
D.
Hepatic Artery Aneurysm:
1. May stimulate hepatic abscess
2. Usually appears as
sonolucency with surrounding
echogenic area (thrombus)
3. Flow of blood changes as blood
swirls and clots
Other Disease Conditions, continued …
E. Klatskin Tumor:
1. Ducts are blocked or fused
a. Tumor at junction of Right
and Left Hepatic Ducts
b. Causes obstructive jaundice
Other Disease Conditions, continued …
F. Courvasier’s Sign:
1. Refers to gallbladder “rate of
fill” with tumor vs. stone
2. Hydrops (edema) of gallbladder
due to tumor in head of
pancreas
Other Disease Conditions, continued …
G. Reidel’s Lobe:
1. Anomalous, tongue-like
extension
2. From right lobe of liver to the
gallbladder
Reidel’s Lobe
R. Lobe
L. Lobe
GB
Reidel’s Lobe
Reidel’s Lobe
VI. Miscellaneous Data
A. Portal Vein: Measurements
1. Length = 5.5 – 8.0 cm
(average = 6.5)
2. Diameter = ~ 1 cm
Misc. Data, continued …
B. Ampulla of Vater
1. Length = 1 – 14 mm
2. Width = 1.5 – 4.5 mm