LIVER SEGMENTAL
ANATOMY
REFERENCE:
http://www.ctisus.com
http://www.ctisus.com/organsys/index.html
Couinad’s Liver Segmental Classification
http://www.ctisus.com/
SEGMENT 1
• SEG 1 is displayed in green.
• Because this segment has a
separate embriologic origin, it
originates from a separate
lobe.
• It is also called the caudate
lobe. Portal supply is generally
provided by small branches
originating from the left main
portal vein, or from segmental
branches from adjacent
segments. It is drained by
small hepatic veins joining
directly to the anterior wall of
the inferior vena cava
SEGMENT 2
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•
•
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Seg 2 displayed in yellow.
This segment is the superior part of
the left lateral segment. Segment 2 is
usually drained by this superior hepatic
vein coursing laterally, and joining the
left hepatic vein before the junction to
the inferior vena cava.
Its portal supply is provided by a
branch originating from the left main
portal branch. In most cases, you can
easily follow this branch from its
origin. Segment 2 is separated from
Segment 4A by a vertical scissura
containing the left hepatic vein.
Segment 2 is separated from Segment
3 by a trans-axial scissura or
transverse scissura containing the left
main portal branch and from segment
1 by the ligamentum venosum. From
the external surface of the liver,
Segment 2 is separated from Segment
4A by the falciform ligament.
SEGMENT 3
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•
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Segment 3 is displayed in light blue.
This segment is the inferior part of the
left lateral segment.
Its portal supply is provided by a
branch originating from the left main
portal branch.
It is usually drained by the left hepatic
vein. Segment 3 is separated from
Segment 4B by a vertical scissura
containing the left hepatic vein, and
from Segment 2 by the tranverse
scissura. Segment 3 is separated from
Segment 1 by the ligamentum
venosum.
From the external surface of the liver,
Segment 3 is separated from Segment
4B by the inferior part of the falciform
ligament.
SEGMENT 4 A
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Segment 4A is displayed in blue. This
segment is the superior part of the left
medial segment, and is also called the
quadrate lobe.
It is usually drained by the left and
middle hepatic veins. Its portal supply
is provided by a branch originating
from the left main portal branch.
Segment 4A is separated from
Segment 2 by a vertical scissura
containing the left hepatic vein.
Segment 4a is separated from
Segment 8 by a vertical scissura
containing the middle hepatic vein, and
from Segment 4B by the transverse
scissura.
Segment 4A is separated from
Segment 2 by the falciform ligament
from the external surface of the liver.
SEGMENT 4 B
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•
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Segment 4B is displayed in pink.
This segment is the inferior part of
the left medial segment, also
called the quadrate lobe. Its portal
supply is provided by a branch
originating from the left main
portal branch. It is usually drained
by the left and the middle hepatic
veins. Segment 4B is separated
from Segment 3 by a vertical
scissura containing the left hepatic
vein, and from segment 4A by the
transverse scissura.
From the external surface of the
liver, Segment 4B is separated
from Segment 3 by the inferior
part of the falciform ligament.
SEGMENT 5
•
•
Segment 5 is displayed in purple.
This segment is the inferior part of the
right anterior segment. Its portal
supply is provided by a branch
originating from the right main portal
branch. It is usually drained by the
middle and the right hepatic veins.
•
In 10% of cases, an inferior hepatic
vein provides additional drainage of
Segment 5 directly to the inferior vena
cava. Segment 5 is separated from
Segment 4B by the vertical scissura
containing the middle hepatic vein and
the gall bladder fossa, and from
Segment 6 by a vertical scissura
containing the right hepatic vein.
Segment 5 is separated from Segment
8 by a transverse scissura containing
the right main portal branch
SEGMENT 6
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•
Segment 6 is displayed in brown.
This segment is the inferior part of
the right posterior segment. Its
portal supply is provided by a
branch originating from the right
main portal branch.
•
It is usually drained by the right
hepatic vein. In 10% of cases, an
inferior hepatic vein provides
additional drainage of Segment 6
directly to the inferior vena cava.
Segment 6 is separated from
Segment 5 by a vertical scissura
containing the right hepatic vein,
and from Segment 7 by the
transverse scissura containing the
right main portal branch
•
SEGMENT 7
• Segment 7 is displayed in
orange.
• This segment is a superior part
of the right posterior segment.
It is usually drained by the right
hepatic vein.
• Its portal supply is provided by
a branch originating from the
right main portal branch.
Segment 7 is separated from
Segment 8 by a vertical
scissura containing the right
hepatic vein, and from
Segment 6 by the transverse
scissura containing the right
main portal branch.
SEGMENT 8
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Segment 8 is displayed in red.
This segment is the superior part of
the right anterior segment. It is usually
drained by the
middle and the right hepatic veins. Its
portal supply is provided by a branch
originating from the right main portal
branch.
Segment 8 is separated from Segment
4A by a vertical scissura containing the
middle hepatic vein and the gall
bladder fossa.
Segment 8 is separated from from
Segment 5 by the transverse scissura
containing the right main portal branch
and from Segment 7 by a vertical
scissura containing the right hepatic
vein.
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