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FIGURE 21.9 Prevailing pattern and important variations of bile ducts draining the right
hemiliver. (From Fischer JE, Jones DB, Pomposelli FB, et al. Fischer’s mastery of surgery, 6th ed.
Philadelphia, PA: Lippincott Williams & Wilkins, 2011.)
FIGURE 21.10 Prevailing pattern and important variations of bile ducts draining the left
hemiliver. (From Fischer JE, Jones DB, Pomposelli FB, et al. Fischer’s mastery of surgery,
6th ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2011.)
Section III / Biliary262
e transverse portion of the left portal vein sends only a few small
branches to Sg4. Large branches from the portal vein to the left liver arise
exclusively beyond the attachment of the ligamentum venosum, that is,
from the umbilical part of the vein (Fig. 21.11). Branches come o both sides
of the vein—those arising from the right side pass into Sg4 and those from
the left supply Sg2 and Sg3. e left portal vein terminates in the ligamen-
tum teres at the free edge of the left liver.
e most common variation is absence of the right portal vein. In
these cases, the right posterior and right anterior sectional portal veins
originate independently from the main portal vein. A rare but poten-
tially devastating anomaly is the absent extrahepatic left portal vein, an
anomaly in which the main portal vein enters the right side of the liver
and courses intrahepatically to supply the left liver. Division of this vein
thinking that it is the right portal vein will lead to portal devascularization
of the entire liver.
Hepatic Veins and Liver Resection
ree large hepatic veins run in the midplane of the liver (middle hepatic
vein), the right intersectional plane (right hepatic vein), and the left
intersectional plane (left hepatic vein). e left hepatic vein begins in the
plane between Sg2 and Sg3 and travels in that plane for most of its length.
FIGURE 21.11 Ramication of the portal vein in the liver. The portal vein divides into right
(A) and left (T
) branches. The branches in the right liver (the sectional branches [c] and [d ],
and the numbered segmental branches) correspond to those of the hepatic artery and bile
duct. The branching pattern on the left is unique. The left portal vein has transverse (T ) and
umbilical portions (U ). The transition point between the two parts is marked by the attach-
ment of the ligamentum venosum (L.V.). All major branches come off the umbilical portion.
The vein ends blindly in the ligamentum teres (L.T.). (Copyright Washington University in
St. Louis.)
Chapter 21 / Liver and Biliary Anatomy 263
In about 10% of individuals, there is more than one large right hepatic
vein; in addition to the right superior hepatic vein (normally called the
right hepatic vein), which enters the IVC just below the level of the dia-
phragm, there is a right inferior hepatic vein, which enters the IVC 5 to
6 cm below this level (Fig. 21.12).
e caudate lobe is drained by its own veins—several short veins that
enter the IVC directly from the caudate lobe. When performing a classi-
cal right hepatectomy, caudate veins are divided in the preliminary portion
of the dissection. As dissection moves up the anterior surface of the vena
cava to isolate the right hepatic vein, one encounters a bridge of tissue lat-
eral to the IVC referred to as the “inferior vena cava ligament.” It connects
the posterior portion of the right liver to the caudate lobe behind the IVC.
is bridge of tissue usually consists of brous tissue, but occasionally is a
bridge of liver parenchyma.
The Plate/Sheath System of the Liver
ere is a system of brous plates and sheaths, which lies on the ventral
surface of the liver and extends into it. Knowledge of the system is of impor-
tance in liver surgery. e fundamentals of the system can be understood
by imagining a shirt with the front cut away to leave only the back and the
sleeves (Fig. 21.13 inset). e back of the shirt would be a plate, and the
sleeves would be sheaths. In the true plate/sheath system, there are four
plates (hilar, cystic, umbilical, and arantian) and several sheaths (Fig. 21.13).
FIGURE 21.12 Hepatic veins. There are normally three hepatic veins: right (R ), middle (M ),
and left (L). Note the segments drained. UV is the umbilical vein, which normally drains
part of Sg4 into the left hepatic vein. The latter is proof that the terminal portion of the
left vein lies in the intersectional plane of the left liver. (Copyright Washington University
in St. Louis.)
Section III / Biliary264
FIGURE 21.13 Plate–sheath system of the liver. A. A schematic of a plate with two
sheaths (see text) B. plate sheath system. (From Strasberg SW, Linehan DC, Hawkins WG.
Isolation of right main and right sectional portal pedicles for liver resection without hepa-
totomy or inow occlusion. J Am Coll Surg 2008;206(2):390–396.)
e hilar plate, the most important plate in liver surgery, is a at sheet, lying
in the coronal plane, posterior to the main bilovascular structures in the
porta hepatis. However, the upper part curves forward to enclose the right
and left bile ducts, the most superior structures in the porta hepatis. It is
this taut, rm, upper curved edge of the hilar plate that is dissected free
from the underside of the liver when “lowering the hilar plate.”
Coming o the right side of the hilar plate like a sleeve is the sheath
of the right portal pedicle. It extends into the liver surrounding the portal
structures that enter it on its free edge, that is, the portal vein, hepatic
artery, and bile duct (Fig. 21.14). e combined structure consisting of
sheath and contents is the right portal pedicle. As the right portal pedicle
enters the liver, it divides into a right anterior and right posterior portal
pedicle supplying the respective sections and then segmental pedicles
supplying the four segments. On the left side, only the segmental struc-
tures are sheathed.
Chapter 21 / Liver and Biliary Anatomy 265
e cystic plate is the ovoid brous sheet on which the gallblad-
der lies (Fig. 21.13). In its posterior extent, the cystic plate narrows to
become a stout cord that attaches to the anterior surface of the sheath
of the right portal pedicle. e latter is a point of anatomical importance
for the surgeon wishing to expose the anterior surface of the right por-
tal pedicle, since this cord must be divided to do so. With severe chronic
inammation, the cystic plate may become shortened and thickened so
that the distance between the top of the cystic plate and the right portal
pedicle is likewise much shorter than usual. is places the structures in
the right pedicle in danger during cholecystectomy in which dissection
is performed “top down” as a primary strategy. e other plates are the
umbilical and arantian, which underlie the umbilical portion of the left
portal vein and the ligamentum venosum respectively (Fig. 21.13). e
other sheaths carry segmental bilovascular pedicles of the left liver and
caudate lobe.
Liver Capsule and Attachments
e liver is covered with a thin brous capsule that covers the entire organ
except for the large “bare area” posteriorly. ere, the organ is in contact
with the IVC and diaphragm. e bare area stretches superiorly to include
the termination of the three hepatic veins and ends in a point, which is
also where the attachment of the falciform ligament ends. e limit of the
bare area, where the peritoneum passes between the body wall and the
liver, is called the coronary ligament. It is one of three structures, which
connect the liver to the abdominal wall “dorsally,” the other two being the
right and left triangular ligaments. e liver also has another much smaller
bare area, where the hepatoduodenal ligament and the lesser omentum
attach on the “ventral” surface. It is here that the portal structures enter
the liver at the hilum. e ligamentum teres (“round”) is the obliterated
left umbilical vein and runs in the free edge of the falciform ligament from
the umbilicus to the termination of the umbilical portion of the left portal
vein. e falciform ( falciform = “scythe shaped”) is the lmy fold that runs
in between the anterior abdominal wall above the umbilicus and attaches
to the anterior surface of the liver between the left medial and left lateral
sections. e ligamentum venosum, the residual ductus venosus, is a lmy
FIGURE 21.14 Isolation of the right portal pedicle and sectional pedicles by technique of
dissection on surface of pedicles. No inow occlusion or separate hepatotomies are used
(see Fischer et al., 2011). The umbilical tape in the upper right of the photograph is around
the bridge of the liver tissue over the umbilical ssure. (From Strasberg SW, Linehan DC,
Hawkins WG. Isolation of right main and right sectional portal pedicles for liver resection
without hepatotomy or inow occlusion. J Am Coll Surg 2008;206(2):390–396.)
Section III / Biliary266
cord that extends from the termination of the transverse portion of the
left portal vein to the left hepatic vein along the junction of the left lateral
section and the caudate lobe.
GALLBLADDER AND EXTRAHEPATIC BILE DUCTS
Gallbladder
e gallbladder lies on the cystic plate. e lower edge of the gallbladder
forms one side of the hepatocystic triangle. e other two sides are the
right side of the CHD and the liver. Eponyms covering this anatomy (Calot,
Moosman, etc.) are confusing and should be abandoned. e hepatocystic
triangle contains the cystic artery and cystic node and sometimes a portion
of the right hepatic artery as well as fat and brous tissue. Clearance of this
triangle along with the isolation of the cystic duct and elevation of the base
of the gallbladder o the lower portion of the cystic plate gives the “criti-
cal view of safety,” which we have described for identication of the cystic
structures during laparoscopic cholecystectomy.
A large number of minor curiosities of the gallbladder, for example,
phrygian cap, have been described. e following are anomalies of impor-
tance to the biliary surgeon.
Double Gallbladder
is is a rare anomaly but can be the cause of persistent symptoms after
resection of one gallbladder. A gallbladder may also be bid, which usually
does not cause symptoms, or have an hourglass constriction that may cause
symptoms due to obstruction of the upper segment.
Agenesis of the Gallbladder
Agenesis occurs in about 1/8,000 patients. It can be dicult to recognize.
When agenesis is suspected, it may be conrmed by axial imaging. If doubt
remains, laparoscopy is denitive.
Cystic Duct
A tubular structure normally 1 to 2 cm in length and 2 to 3 mm in
d
iameter.
It usually joins the CHD at an acute angle to form the CBD. e cystic duct
normally joins the CHD approximately 4 cm above the duodenum. However,
the cystic duct may enter at any level up to the right hepatic duct and down
to the ampulla. e cystic duct may also join the right hepatic duct either
when the right duct is in its normal position or in an aberrant location. e
cystic duct contains a spiral valve.
ere are three patterns of conuence of the cystic duct and CHD
(Fig. 21.15). In 20% of patients in which there is a parallel union, injury to the
CHD may occur by dissecting low on the cystic duct (Fig. 21.15). When mak-
ing a choledochotomy at this level, the incision should be started slightly
to the left side of the midplane of the bile duct in order to avoid entering a
septum between the fused cystic duct/common hepatic duct. When per-
forming cholecystectomy, the cystic duct should be occluded in such a way
that there is a visible section of cystic duct below the clip closest to the CBD.
Although a gallbladder with two cystic ducts has been described, it is
an extreme rarity. When two “cystic ducts” are identied, it is likely that cys-
tic duct is congenitally short or has been eaced by a stone and that the two
structures thought to be dual cystic ducts are, in fact, the CBD and the CHD.
Cystic Artery
e cystic artery is usually 1 to 2 mm in diameter and normally arises from
the right hepatic artery in the hepatocystic triangle. e cystic artery may
Chapter 21 / Liver and Biliary Anatomy 267
arise from a right hepatic artery that runs anterior to the CHD. e cystic
artery may also arise from the right hep atic artery on the left side of the CHD
and run anterior to this duct, while the right hepatic artery runs behind it.
Such cystic arteries tend to tether the gallbladder and make dissection of
the hepatocystic triangle more dicult. e cystic artery may arise from a
replaced right hepatic artery arising from the SMA. In this case, the cystic
artery (and not the cystic duct) tends to be in the free edge of the fold lead-
ing from the hepatoduodenal ligament to the gallbladder. is should be
suspected whenever the “cystic duct” looks smaller than the “cystic artery.”
Usually, the cystic artery runs for 1 to 2 cm to meet the gallbladder
superior to the insertion of the cystic duct. e artery ramies into an ante-
rior and posterior branch at the point of contact with the gallbladder. ese
branches continue to divide on their respective surfaces. Sometimes, the
cystic artery divides into branches before the gallbladder edge is reached.
In that case, the anterior branch may be mistaken for the cystic artery
proper and the posterior branch may not be discovered until later in the
dissection—sometimes by inadvertent division with hemorrhage. e
artery may ramify into several branches before arriving at the gallbladder
giving the impression that there is no cystic artery. e anterior and poste-
rior branches may arise independently from the right hepatic artery, giving
rise to two distinct cystic arteries. ere are many other variations.
Multiple small cystic veins drain into intrahepatic portal vein branches
by passing into the liver around or through the cystic plate. Sometimes,
there are cystic veins in the hepatocystic triangle that run parallel to the
cystic artery to enter the main portal vein.
Cystic Plate
e cystic plate has been described previously. Small bile ducts may pen-
etrate the cystic plate to enter the gallbladder. ese “ducts of Luschka” are
very small, usually submillimeter accessory ducts. However, when divided
FIGURE 21.15 The three types of cystic duct/common hepatic duct conuence. The parallel
union conuence is shown in the middle. Dissection of this type of cystic duct (arrow) may
lead to injury to the side of CHD. During laparoscopic cholecystectomy, this is often a cau-
tery injury. (Adapted from Warrren KW, McDonald WM, Kune GA. Bile duct strictures: new
concepts in the management of an old problem. In: Irvine WT (ed). Modern trends in surgery.
London, UK: Butterworth, 1966. Copyright Washington University in St. Louis.)
Section III / Biliary268
during a cholecystectomy, postoperative bilomas may occur. Bilomas and
hemorrhage may also be caused by penetration of the cystic plate during
dissection. In about 10% of patients, there is a large peripheral bile duct
immediately deep to the plate, disruption of which will cause copious bile
drainage. e origin of the middle hepatic vein is also in this location,
and if it is injured, massive hemorrhage may ensue. ere is areolar tissue
between the muscularis of the gallbladder and the cystic plate. At the top
of the gallbladder, the layer is very thin. As one progresses downward, the
areolar layer thickens. If dissection from the top of the gallbladder down-
ward is carried on the gallbladder leaving the areolar tissue on the cystic
plate, one will arrive onto the posterior surface of the cystic artery and
cystic duct. Conversely, if dissection is carried downward on the cystic
plate leaving the areolar tissue on the gallbladder, one will arrive onto the
surface of the right portal pedicle. If this is not anticipated, structures in
the right portal pedicle may be injured. erefore, the proper plane of dis-
section is between the gallbladder and the areolar tissue.
Extrahepatic Bile Ducts
e CHD is formed by the union of the right and left hepatic ducts. e
union normally occurs at the right extremity of the base of Sg4 anterior and
superior to the bifurcation of the portal vein. e CHD travels in the right
edge of the hepatoduodenal ligament for 2 to 3 cm where it joins with the
cystic duct to form the CBD. e latter has a supraduodenal course of 3 to
4 cm and then passes behind the duodenum to run in or occasionally behind
the pancreas to enter the second portion of the duodenum. e external
diameter of the CBD varies from 5 to 13 mm when distended to physiologic
pressures. However, the duct diameter at surgery, that is, in fasting patients
with low duct pressures, may be as small as 3 mm. Radiologically, the inter-
nal duct diameter is measured on fasting patients. Under these conditions,
the upper limit of normal is about 8 mm. Size should never be used as a
sole criterion for identifying a bile duct. Caution is required in situations
in which a structure seems larger than the expected norm. Although the
cystic duct may be enlarged due to passage of stones, a surgeon should take
extra precautions before dividing a “cystic duct” that is greater than 2 mm
in diameter because the CBD can be 3 mm in diameter and aberrant ducts
may be smaller.
Anomalies of Extrahepatic Bile Ducts
As already noted, there are biliary anomalies of the right and left ductal
systems, which can aect outcome of hepatic surgery. e same is true for
biliary surgery. e most important clinical anomaly is low insertion of the
right hepatic ducts referred to above. Because of its low location, it may be
mistaken to be the cystic duct and injured during cholecystectomy. is is
even more likely to occur when the cystic duct unites with an aberrant duct
as opposed to joining the CHD. e anomalies of a right hepatic duct enter-
ing the gallbladder and the absent CHD have been discussed above. Left
hepatic ducts can also join the CHD at a low level. ey are less prone to be
injured since the dissection during cholecystectomy is on the right side of
the biliary tree.
Extrahepatic Arteries
e course of these arteries has been described above. Anomalies of the
hepatic artery may be important in gallbladder surgery. Normally, the right
hepatic artery passes posterior to the bile duct (80%) and gives o the cys-
tic artery in the hepatocystic triangle. However, in 20% of cases, the right
hepatic artery runs anterior to the bile duct. e right hepatic artery may
Chapter 21 / Liver and Biliary Anatomy 269
lie very close to the gallbladder, and chronic inammation can draw the
right hepatic artery directly onto the gallbladder, where it lies in an inverse
U-loop and is prone to injury. In the “classical injury” in laparoscopic chole-
cystectomy in which the CBD is mistaken for the cystic duct, an associated
right hepatic artery injury is very common, since that right hepatic artery
is considered to be the cystic artery.
Blood Supply of Bile Ducts
Many studies, dating back to the 19th century, have examined the blood
supply of the extrahepatic bile ducts in cadaveric specimens. An important
observation made by Rappoport is that the bile ducts are supplied solely by
the hepatic artery, unlike the liver that has a dual blood supply from the artery
and the portal vein. e arterial blood supply has three anatomic elements—
aerent arteries, marginal arteries, and epicholedochal plexus (Fig. 21.16).
e aerent vessels are branches of the hepatic arteries and less com-
monly of the SMA or other upper abdominal arteries. e most constant
and important artery supplying the bile duct is the posterior superior
pancreaticoduodenal artery, usually the rst branch of the gastroduode-
nal artery. Arterial twigs are sent to the duct as the artery winds around
the lower end of the duct. ese branches supply the retroduodenal and
intrapancreatic bile duct but also ascend the bile duct to give supply to the
supraduodenal bile duct. e lowest portion of the duct near the ampulla
is also supplied by the anterior superior pancreatic artery and the inferior
pancreaticoduodenal artery. Other vessels, which commonly send aerents
to the supraduodenal bile duct, are the proper hepatic artery, cystic artery,
Epicholedochal pl
exus
Right hepatic artery
Cystic artery
Posterior superior
pancreato-duodenal
artery
Gastroduodenal artery
Common hepatic artery
Proper hepatic artery
Left hepatic artery
Marginal arteries
FIGURE 21.16 Blood supply to bile ducts. The three elements—the
afferent arteries, marginal arteries, and epicholedochal plexus—
are shown. (From Fischer JE, Jones DB, Pomposelli FB, et al.
Fischer’s mastery of surgery, 6th ed. Philadelphia, PA: Lippincott
Williams & Wilkins, 2011.)
Section III / Biliary270
and artery to segment 4. However, virtually all extrahepatic arteries arising
from the common hepatic artery can send small branches to the bile ducts.
Also, body wall collaterals such as phrenic arteries can at times supply the
bile ducts. e idea that the extrahepatic bile duct, that is, CHD and CBD, is
supplied by the arteries that join it only at the bottom and top of its course
is incorrect. Supplying arteries from the cystic artery, right and left hepatic
arteries, and proper hepatic artery may join it along its length.
e aerent vessels empty into the longitudinal or “marginal” arter-
ies, which run parallel to the long axis of the bile duct. ese vessels are
disposed at 3, 9, and, less commonly, 12 o’clock on the CBD/CHD or run
across the top of the conuence of the right and left hepatic ducts. is hilar
marginal artery is of great importance in maintaining blood supply to the
liver when one hepatic artery (right or left) is occluded.
e third element, the “epicholedochal plexus,” is a ne arterial plexus
that lies on and surrounds the entire CBD and the left and right hepatic
ducts. e part around the hepatic ducts is the hilar component of the epi-
choledochal plexus. e vessels of the plexus tend to run along the long
axis of the ducts so that on the common duct many of the vessels are verti-
cal while that around the conuence and the right and left ducts they are
disposed horizontally. Branches of the epicholedochal plexus pierce the
bile duct and supply it through the deeper and ner intracholedochal plexi
within the wall of the bile duct.
Transection of the bile duct may result in ischemia of the duct. For
instance, if the duct is transected at the level of the duodenum, ischemia of
a portion of the bile duct above this level may occur since blood ow origi-
nating from the superior pancreaticoduodenal artery and passing up along
the marginal artery is cut o. is problem is thought to be an important
contributory cause to the frequent failure of choledochocholedochostomy
as a form of biliary reconstruction. To avoid this problem, hepaticojeju-
nostomy is used and the bile duct is trimmed back to within 1 cm of the
conuence.
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