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In 1888, Rex described the midline division of the liver, and in the A
1950s Claude Couinaud’s detailed description of the segmental
anatomy of the liver formed the basis for subsequent advances in liver
Left hepatic vein
imaging and surgery. Goldsmith and Woodburne also published a
detailed description of liver anatomy in 1957 but used a different ter-
Left posterior sector
minology; confusion in hepatic nomenclature has persisted for several
decades.
Couinaud divided the right and left hemi-livers into two sectors each,
according to the secondary divisions of the portal vein. In the right
hemi-liver, the anteromedial and posterolateral sectors were each sub-
Left portal fissure
divided into a superior and an inferior segment, producing a total of
four segments. In the left hemi-liver, the medial sector was divided into
two segments separated by the falciform ligament and ligamentum Umbilical
teres, while the lateral sector consisted of a single segment (II). The fissure
smallest segment, which Couinaud designated segment I, was located
in the central and posterior part of the liver between the bifurcation of
the portal vein and the inferior vena cava, and had independent hepatic Left anterior sector
vein and portal vein tributaries. Couinaud, therefore, described eight B
liver segments, numbered I to VIII: segments II, III and IV made up
the left hemi-liver and segments V, VI, VII and VIII made up the right
hemi-liver. In 1994, he added segment IX to describe the small region
of the right hemi-liver lying adjacent to the right side of the inferior
vena cava, but later recognized that this was better considered as part
of segment I.
In 1982, Henri Bismuth used Couinaud’s anatomical descriptions
with some modifications as the basis for developing anatomical liver
resections (Bismuth 2013). Couinaud’s studies had been based on cor-
rosion casts of injected cadaveric livers that had undergone slight post-
mortem flattening from resting on a firm surface. Bismuth renamed
Couinaud’s anteromedial and posterolateral sectors in the right hemi-


liver as anterior and posterior, and also challenged Couinaud’s subdivi- Fig. 67.16 A, The umbilical fissure that divides the anterior sector of the
sion of the left liver. Couinaud had described two sectors: a lateral sector left lobe into two segments is, in fact, an artificial scissure. B, When it is
consisting of a single segment, and a medial sector consisting of two suppressed, the anterior sector appears as a single segment. (Redrawn
segments separated by a branch of the left portal vein lying in continuity with permission from Bismuth H. Surgical anatomy and anatomical
with the round ligament. Bismuth considered that this went against surgery of the liver. World J Surg 1982;6:3–9, Springer.)
Couinaud’s own description of individual segments containing a major
branch of the portal vein, and suggested that the left medial sector also
Middle segment Left segment
consisted of a single segment, i.e. segments III and IV were, in fact,
‘half-segments’ (Fig. 67.16). This scheme created a single sector con-
taining two segments within the left hemi-liver. To avoid confusion,
Bismuth chose to retain the segment numbers III and IV, albeit recog-
nizing them as half-segments. The Bismuth classification recognized
two hemi-livers, three sectors (right posterior, right anterior and left)
and seven segments: segments 6 and 7 in the right posterior sector,
segments 5 and 8 in the right anterior sector, half-segments 3 and 4 and
segment 2 in the left sector, and segment 1 (numbering was changed
from Roman to Arabic).
In 1986, Ken Takasaki described a different basis for subdividing the
gross architecture of the liver, in which the portal vein had three
branches (right, middle and left) and there were just two hepatic veins
(right and middle, the left hepatic vein being a tributary of the middle
hepatic vein; Fig. 67.17). Takasaki had divided the liver into three parts
of almost equal volume, based on the three branches of the portal vein
and the two hepatic veins. Apart from the terms used, Takasaki’s descrip-
tion is similar to Bismuth’s modification of Couinaud’s anatomy in that


the liver is considered to consist of three, and not four, territories. It
fails to take into account the division of the left side of the liver by the
falciform and round ligaments. The major advantage of Takasaki’s
description is the individualization of the middle part, facilitating the
concept of central hepatectomy.
Three secondary branches of the
Right segment Glissonian pedicle
Fig. 67.17 The liver is divided into three segments and a caudate area,
according to the ramification of the Glissonian pedicles. (Redrawn based
on Takasaki K, Koabayashi S, Tanaka S, et al 1986 Highly selected
hepatic resection by Glissonian sheath-binding method. Dig Surg 3: 121.)


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In 1998, the International Hepato-Pancreato-Biliary Association 1957), bisegmentectomy (Couinaud 1957), resection of half a segment
(IHPBA) developed an international committee on nomenclature of (Takasaki et al 1986), and left lateral sectionectomy (Terminology
hepatic anatomy and resections, and this reported to the IHPBA General Committee of the IHPBA 2000). To avoid confusion, the term lobec-
Assembly in Brisbane in 2000 (Terminology Committee of the IHPBA tomy is no longer used but Bismuth has argued for a return to classical
2000). The chairman of the committee, Steven M. Strasberg, highlighted anatomy and the use of the term left lobectomy. He has also argued
the confusion that arose from applying multiple terms to the same that all hepatectomies should be defined by the specific segments that
anatomical structure or operative procedure, and from using the same are resected. Thus, removal of a single segment should be described as
term to describe more than one structure or operation. For example, in ‘segmentectomy n’ where n is the specific number of the segment
1997, there were 13 terms in use for the plane that defined the water- removed. Resection of two segments is a ‘bisegmentectomy n + n1’, and
shed between the right and left hemi-livers (called the midplane of the that of three segments a trisegmentectomy n + n1 + n2 (Bismuth 2013).
liver by the committee), and the terms ‘lobe’, ‘lobectomy’, ‘segment’ Masatoshi Makuuchi, a member of the IHPBA Brisbane 2000 com-
and ‘segmentectomy’ were being used to describe different parts of the mittee on nomenclature, has recently questioned the current status,
liver and associated procedures, depending on whether the surgeon was pointing out that the differences in portal vein branching patterns in
European or North American. The anatomical basis for the Brisbane the left and right hemi-livers have been the major obstacle in consist-
2000 nomenclature was the usual branching pattern of the hepatic ently classifying liver territories to satisfy what is known about hepatic


arteries and bile ducts within the liver. The ramification of the portal embryology, as well as descriptive and surgical anatomy. Makuuchi
vein was said to follow an identical pattern in the right hemi-liver but (2013) has commented that, in the embryo, the right and left hemi-
to be different in the left hemi-liver. Three orders of branching resulted livers develop synchronously and that the right and left umbilical veins
in successive division of the liver into two hemi-livers, four sections and initially join the right and left branches of the portal vein, respectively.
eight segments. Watershed areas between territories subserved by At 4–5 weeks’ gestation, the right umbilical vein is resorbed so that the
branches of the hepatic artery and bile duct were demarcated by the volume of the left side of the liver increases compared to the right, but
midplane of the liver, a right and left intersectional plane, and several after occlusion of the left umbilical vein after birth, the left hemi-liver
intersegmental planes. The terminology of liver resections was based gradually shrinks and the right side enlarges. Makuuchi argues that
directly on the anatomical terminology, and individual resections were the left lateral sector (segment II) and right lateral sector (segments
termed hemihepatectomy (or hepatectomy), sectionectomy and seg- VI and VII) were so named by Couinaud because the portal vein
mentectomy; an extended resection of three sections was called a trisec- branches to both sectors are the first large branches arising from the
tionectomy (Fig. 67.18). There has been a clear trend towards adoption left and right divisions of the portal vein. These two sectors also share
of this terminology since 2000 but it has not been universal, not least the characteristic of having a major hepatic vein running on their
because the classification has some anatomical deficiencies. In particu- medial border. This is contrary to the views of both Bismuth and Taka-
lar, Couinaud’s segments II and III became the left lateral section saki, who maintain that segment II should be amalgamated with seg-
(which meant that removal became a left lateral sectionectomy) but this ments III and IV into a single sector, and of the IHPBA Brisbane 2000


does not accurately represent the anatomical division. The introduction nomenclature committee, who considered segment IV to be a full
of the term ‘section’, as opposed to ‘sector’, was intended to introduce sector. Makuuchi postulates that the left lateral sector shrinks after birth
simpler terms for segments II and III (left lateral section) and segment and, if segment IV is determined to be a sector, then the right medial
IV (left medial section) that would mirror the arrangement in the right sector of the liver should be demarcated by a plane that corresponds to
hemi-liver (right anterior and posterior sections). the embryonic right umbilical vein. As the main portal pedicle should
Bismuth argued that classification of the lateral part of the left hemi- be located at the centre of the sector and not at its border, if the left
liver was particularly problematic. According to Couinaud, individual and right hemi-livers are each divided into two sectors, it is more logical
liver territories contain portal vein branches but are separated by the to regard segment II as a sector, as suggested by Couinaud, rather than
major hepatic veins. However, the lateral part of the left hemi-liver is segment IV.
demarcated by the falciform and round ligaments. Resection of this part Makuuchi also discussed the use of the term ‘extended’, as proposed
of the liver remains one of the most commonly performed hepatecto- by Bismuth and the IHPBA Brisbane 2000 nomenclature committee.
mies. In classical anatomy, the term lobe relates to part of an organ He suggested that ambiguity could be eliminated by adopting the
defined by an external fissure; removal of the part of the liver to the wording ‘extended into segment X’, where X is the specific segment
left of the falciform and round ligaments was originally called a left number identified by Couinaud. Further revision of the nomenclature
lobectomy. According to subsequent classifications, this resection has is likely in the future (Strasberg and Phillips 2013).
been termed a left lateral segmentectomy (Goldsmith and Woodburne


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Fig. 67.18 Resectional terminology. (Redrawn with
Anatomical term Couinaud segments Term for surgical resection Diagram permission from Terminology Committee of the
(pertinent area is shaded) International Hepato-Pancreato-Biliary Association.
The Brisbane 2000 terminology of liver anatomy
and resections. HPB 2000;2:333–9.)
2
8
Right liver Sg 5-8 Right hepatectomy 7 4 3
or or
Hemi-liver Right hemihepatectomy 6 5
2
8
Left liver Sg 2-4 Left hepatectomy 7 4 3
or or
Hemi-liver Left hemihepatectomy 6 5
2
8
Right anterior Sg 5,8 Right anterior sectionectomy 7 4 3
section
5
6
2
8
Right posterior Sg 6,7 Right posterior sectionectomy 7 4 3
section
5
6
2
8
7 4 3
Left medial Sg 4 Left medial sectionectomy
section 5
6
2
8
Left lateral Sg 2,3 Left lateral sectionectomy 7 4 3
section
5
6
2
8
Segments 1-8 Any one of Sg 1-8 Segmentectomy 7 4 3
(e.g. segmentectomy 6)
5
6
2
8
Two contiguous Any two of Sg 1-8 Bisegmentectomy 7 4 3
segments in continuity (e.g. bisegmentectomy 5,6)
5
6
Extended resections (Trisectionectomy)
2
Right trisectionectomy (preferred term) 8
or 7 4 3
Sg 4-8
Extended right hepatectomy
5
or 6
Extended right hemihepatectomy
Left trisectionectomy (preferred term) 2
8
or 7 4 3
Extended left hepatectomy
Sg 2,3,4,5,8 or 5
6
Extended left hemihepatectomy


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structures are usually accompanied by one or more lymphatic vessels can be divided into three zones: zone 1 (periportal) is nearest to the
and nerves. terminal branches of afferent vessels; zone 2 is the intermediate zone;
The liver parenchyma consists of a complex network of epithelial and zone 3 is the area closest to the central vein.
cells, supported by connective tissue, and perfused by a rich blood
supply from the portal vein and hepatic artery. The epithelial cells, Blood supply
hepatocytes, carry out the major metabolic activities, but additional cell
types possess storage, phagocytic and mechanically supportive func-
Preterminal hepatic arterioles within the acini convey arterial blood to
tions. In the mature liver, hepatocytes are arranged mainly in plates (or
the sinusoids, mostly via a fine capillary plexus that drains to branches
cords when seen in two-dimensional sections) that are usually only one
of the portal veins; a small proportion of arterial blood passes directly
cell thick and are separated by venous sinusoids, which anastomose
to the hepatic sinusoids, bypassing these capillary plexuses. Sinusoids
with each other via gaps in the plates (Fig. 67.20; see Fig. 67.22). Until
thus contain mixed venous and arterial blood. Central veins from adja-
about 7 years of age, plates are normally two cells thick. This pattern
cent lobules form interlobular veins that unite as hepatic veins and
recurs in liver regeneration, when a mixture of hyperplasia and hyper-
drain to the inferior vena cava.
trophy results in cell plates that are several cells thick and composed of
larger multinucleated hepatocytes, reverting over the course of about a
Hepatic plates (cords)
year to single cell thickness.
Bile is secreted by hepatocytes and collected in a network of minute
tubes (canaliculi). The hepatocytes can therefore be regarded as exo- The endothelium of the sinusoids is fenestrated and lacks a basal
crine cells, secreting bile into the alimentary tract via the extrahepatic lamina, which enables it to act as a dynamic blood filter (Fraser et al


bile ducts. Their other metabolic functions involve complex biochemi- 1995). The sinusoids are separated from the plates of hepatocytes by a
cal exchanges with the blood. narrow gap, the perisinusoidal space of Disse, which is normally
The fetal liver is a major haemopoietic organ; erythrocytes, leuko- 0.2–0.5 µm wide but which distends in hypoxic states. The space con-
cytes and platelets develop from mesenchyme covering the sinusoidal tains interstitial fluid, the microvilli of adjacent hepatocytes, hepatic
endothelium. stellate cells, fine collagen fibres (mostly type III, with some types I and
IV), and occasional non-myelinated nerve terminals.
Lobulation of the liver A network of minute, interconnecting biliary canaliculi (approxi-
mately 1 µm in diameter) runs between the hepatic plates. The canal-
iculi are formed by the apposed plasma membranes of adjacent
The structural unit of the liver is the lobule: a roughly hexagonal
hepatocytes sealed by tight junctions. They conduct bile to the canals
arrangement of plates of hepatocytes, separated by intervening sinu-
of Hering, trough-like structures lined by cholangiocytes and hepato-
soids that radiate outwards from a central vein, with portal triads at the
cytes within the liver lobules. Each canal collects bile from multiple
vertices of each hexagon (Fig. 67.21; see Fig. 67.19). The central veins
canaliculi and empties into a bile ductule (lined by cholangiocytes),
drain into the hepatic veins. In some species, the classic lobular units
which in turn drains into an interlobular bile duct within the portal
are delimited microscopically by distinct connective tissue septa.
tracts (Roskams et al 2004). The flow of bile is thus towards the periph-
However, the lobular organization of the human liver is not immedi-
ery of the lobule, in the opposite direction to the blood flow, which is
ately evident in histological sections; the lobules do not have distinct
centripetal.
boundaries, and connective tissue is sparse. The plates do not pass
straight to the periphery of a lobule like the spokes of a wheel but run
Cells of the liver


irregularly as they anastomose and branch.
Detailed studies of human liver, using three-dimensional reconstruc-
tion and morphometric analysis combined with histopathological Resident cells of the liver include hepatocytes, hepatic stellate cells (also
observations, have revealed a highly ordered arrangement of functional known as fat-storing Ito cells), sinusoidal endothelial cells, macro-
units: the hepatic (portal) acini. Each acinus is an approximately ovoid phages (Kupffer cells), the epithelial cells of the biliary tree (cholangio-
mass of tissue, orientated around a terminal branch of a hepatic arteri- cytes), hepatic stem cells, natural killer lymphocytes (pit cells), and
ole and portal venule, and with its long axis defined by two adjacent connective tissue cells of the capsule and portal tracts (see Fig. 67.19B).
central veins (see Fig. 67.19). It includes the hepatic tissue served by
these afferent vessels and is bounded by adjacent acini. Hepatocytes About 80% of the liver volume and 60% of its cellular
The acinar definition of hepatic microarchitecture has clarified the population is made up of hepatocytes (parenchymal cells) (see Fig.
interpretation of liver histopathology, particularly in relation to zones 67.21; Fig. 67.22). They are polyhedral, with 5–12 sides, and measure
of hypoxic damage, glycogen deposition and removal, and toxic injury, 20–30 µm across. Their nuclei are round, euchromatic and often tetra-
all of which are related to the direction of blood flow. There are also ploid, polyploid or multiple, with two or more in each cell. Their
real metabolic differences between hepatocytes within the acini, which cytoplasm typically contains a considerable amount of rough and
Central vein Interlobular septum
Central vein
Hepatocyte
Kupffer cells
Sinusoid
Bile canaliculi
Hepatic artery
Bile duct
Hepatic
portal vein
Bile duct Hepatic artery Hepatic portal vein Portal triad Bile ductules
Fig. 67.21 The hepatic microstructure. Sinusoidal endothelial cells are not shown.


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Fig. 67.20 Scanning electron micrographs of a
CV resin corrosion cast of the human liver
demonstrating the three-dimensional arrangement
of the hepatic sinusoids. A, A portal vein (PV)
branch within a portal triad × 33 100 µm.
B, Sinusoids and central veins (CV) × 37 100 µm.
C, A sinusoidal network ×330 10 µm. D, Sinusoidal
CV endothelial cells × 7000 1 µm. (Courtesy of
Professor Greg Jones, University of Otago, New
Zealand).
PV
A B
C D


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Fig. 67.22 A schematic illustration of a
hepatocyte and adjacent sinusoids.
(Redrawn from O’Grady J, Lake JR,
Howdle PD. Comprehensive Clinical
Fenestrae Hepatology, Mosby 2000.)
Kupffer cell
Endothelial cells
Sinusoid
Space of Disse Stellate cell
Smooth endoplasmic
Vacuole
reticulum
Mitochondrion
Tight junction
Golgi apparatus
Biliary canaliculus
Nucleus (chromatin)
Nucleolus
Peroxisome Rough endoplasmic
reticulum
Gap junction
Lipid
Desmosome Lysosome
Collagen fibres
Sinusoid
smooth endoplasmic reticulum, many mitochondria, lysosomes and homeostasis and regeneration. Hepatic stellate cells also play a major
well-developed Golgi apparatus, all features that indicate a high meta- role in pathological processes (Yin et al 2013). In response to liver
bolic activity. Glycogen granules and lipid vacuoles are usually promi- damage, they become activated and predominantly myofibroblast-like.
nent. Numerous large peroxisomes and vacuoles containing enzymes, They are responsible for the replacement of damaged hepatocytes with
e.g. urease in distinctive crystalline forms, indicate the complex metab- collagenous scar tissue, a process called hepatic fibrosis, that is seen
olism of these cells. Their role in iron metabolism is reflected by initially in zone 3, around central veins. Fibrosis can progress to cir-
the presence of storage vacuoles containing crystals of ferritin and rhosis, where the parenchymal architecture and pattern of blood flow
haemosiderin. within the liver are destroyed, with major systemic consequences.
The surfaces of hepatocytes facing the sinusoids exhibit numerous
microvilli, approximately 0.5 µm long, creating a large surface area Sinusoidal endothelial cells Hepatic venous sinusoids are gener-
(approximately 70% of the hepatocyte surface) exposed to blood ally wider than blood capillaries and are lined by a thin but highly
plasma. Elsewhere, hepatocytes are linked by numerous gap junctions fenestrated endothelium that lacks a basal lamina. The endothelial cells


and desmosomes. Lateral plasma membranes of adjacent hepatocytes are typically flattened, each with a central nucleus, and are joined to
form microscopic channels, the bile canaliculi, which are specialized each other by junctional complexes. The fenestrae are grouped in clus-
regions of intercellular space formed by apposing grooves in hepatocyte ters with a mean diameter of 100 nm, allowing plasma direct access to
plasma membranes, sealed from extraneous interstitial space by the basal plasma membranes of hepatocytes. Their cytoplasm contains
tight junctions. Four types of transmembrane molecules (occludins, numerous transcytotic vesicles.
claudins, junctional adhesion molecules and coxsackie virus and aden-
ovirus receptors) constitute the core units of the functional protein Kupffer cells Kupffer cells are hepatic macrophages derived from
complexes of the tight junctions (Lee 2012) (see Fig. 1.19). Individual circulating blood monocytes and originate in the bone marrow. They
tight junction complexes, either alone or in combination, are involved are long-term hepatic residents and lie within the sinusoidal lumen
in signalling pathways in health and disease. Numerous membrane- attached to the endothelial surface. Kupffer cells are irregular in shape
bound exocytotic vesicles cluster near the lumen of the canaliculi and have long processes that extend into the sinusoidal lumen. They
because the secretion of bile is targeted at the canalicular plasma mem- form a major part of the mononuclear phagocyte system, which is
brane. The tight junctions surrounding the biliary canaliculi prevent responsible for removing cellular and microbial debris from the circula-
bile from entering the interstitial fluid or blood plasma, thereby creat- tion, and for secreting cytokines involved in defence. They remove
ing a blood–bile barrier. aged and damaged red cells from the hepatic circulation, a function
normally shared with the spleen but fulfilled entirely by the liver after
Hepatic stellate cells Hepatic stellate cells are much less numerous splenectomy.
than hepatocytes. They are irregular in outline and lie within the per-
isinusoidal space of Disse between the sinusoids and the hepatocyte Hepatic stem cells Hepatic stem cells are undifferentiated, pluripo-


plates. They are thought to be mesenchymal in origin and are character- tential cells and are understood to reside around the canals of Hering;
ized by numerous cytoplasmic lipid droplets. These cells secrete most they are derived from the ductal plate in fetal livers. Their progeny are
of the intralobular matrix components, including collagen type III small epithelial cells (8–18 µm) with a large oval nucleus and scanty
(reticular) fibres. They store the fat-soluble vitamin A in their lipid cytoplasm, expressing both biliary epithelial and hepatocyte markers
droplets and are a significant source of growth factors involved in liver (Roskams et al 2010).


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Bonus e-book images
Fig. 67.10 Common hepatic artery variants. scissure. B, When it is suppressed, the Fig. 67.18 Resectional terminology.
anterior sector appears as a single segment.
Fig. 67.11 Hepatic arteriograms. Fig. 67.20 Scanning electron micrographs of
Fig. 67.17 The liver is divided into three a resin corrosion cast of the human liver
Fig. 67.16 A, The umbilical fissure that segments and a caudate area, according to demonstrating the three-dimensional
divides the anterior sector of the left lobe the ramification of the Glissonian pedicles. arrangement of the hepatic sinusoids.
into two segments is, in fact, an artificial
KEY REFERENCES
Bismuth H 1982 Surgical anatomy and anatomical surgery of the liver. Lanouis B, Jamieson GG 1993 Modern operative techniques in liver surgery.
World J Surg 6:5–9. Clinical Surgery International 18. Edinburgh: Elsevier, Churchill
Bismuth H 2013 Revisiting liver anatomy and terminology of hepatec- Livingstone.
tomies. Ann Surg 257:383–6. Makuuchi M 2013 Could we or should we replace the conventional nomen-
Couinaud C 1957 Le Foie: études anatomiques et chirurgicales. Paris: clature of liver resections? Ann Surg 237:387–9.
Masson. Takasaki K, Koabayashi S, Tanaka S et al 1986 Highly selected hepatic resec-
Couinaud’s original descriptive studies of liver segmentation, later updated tion by Glissonian sheath-binding method. Dig Surg 3:121 (abstract).
and translated into English in 1989 as Surgical Anatomy of the Liver Terminology Committee of the International Hepato-Pancreato-Biliary
Revisited. Association 2000 The Brisbane 2000 terminology of liver anatomy and
Goldsmith NA, Woodburne RT 1957 Surgical anatomy pertaining to liver resections. HPB 2:333–9.
resection. Surg Gynecol Obstet 195:310–18. Stringer MD 2009 Eponyms in Surgery and Anatomy of the Liver, Bile Ducts


Healey JE, Schroy PC 1953 Anatomy of the biliary ducts within the human and Pancreas. London: Royal Society of Medicine.
liver: analysis of the prevailing pattern of branchings and the major A concise illustrated account of the derivation and individuals behind the
variations of the biliary ducts. Arch Surg 66:599–616. more common eponyms associated with liver anatomy and surgery.


Liver
1172.e1
76
RETPAHC
REFERENCES
Bismuth H 1982 Surgical anatomy and anatomical surgery of the liver. Lee NP 2012 The blood–biliary barrier, tight junctions and human liver
World J Surg 6:5–9. diseases. Adv Exp Med Biol 763:171–85.
Bismuth H 2013 Revisiting liver anatomy and terminology of hepatec- López-Andújar R, Moya A, Montalvá E et al 2007 Lessons learned from
tomies. Ann Surg 257:383–6. anatomic variants of the hepatic artery in 1,081 transplanted livers. Liver
Burt RP 2003 Phasic contractions of the rat portal vein depend on intracel- Transpl 13:1401–4.
lular Ca2+ release stimulated by depolarization. Am J Physiol Heart Circ McCuskey RS 2004 Anatomy of efferent hepatic nerves. Anat Rec A Discov
Physiol 284:H1808–17. Mol Cell Evol Biol 280:821–6.
Camargo AM, Teixeira GG, Ortale JR 1996 Anatomy of the ostia venae Makuuchi M 2013 Could we or should we replace the conventional nomen-
hepaticae and the retrohepatic segment of the inferior vena cava. J Anat clature of liver resections? Ann Surg 237:387–9.
188:59–64. Michels NA 1966 Newer anatomy of the liver and its variant blood supply
Couinaud C 1957 Le Foie: études anatomiques et chirurgicales. Paris: and collateral circulation. Am J Surg 112:337–47.
Masson. Mirjalili SA, McFadden SL, Buckenham T et al 2012 Anatomical planes: are
Couinaud’s original descriptive studies of liver segmentation, later updated we teaching accurate surface anatomy? Clin Anat 25:819–26.
and translated into English in 1989 as Surgical Anatomy of the Liver
Ohtani O, Ohtani Y 2008 Lymph circulation in the liver. Anat Rec 291:
Revisited.
643–52.


Chaib E 2009 Absence of bifurcation of the portal vein. Surg Radiol Anat Onishi H, Kawarada Y, Das BC et al 2000 Surgical anatomy of the medial
31:389–92. segment (S4) of the liver with special reference to bile ducts and vessels.
Covey AM, Brody LA, Getrajdman GI et al 2004 Incidence, patterns, and Hepatogastroenterology 47:143–150.
clinical relevance of variant portal vein anatomy. AJR Am J Roentgenol Rex H 1888 Beiträge zur Morphologie der Säugerleber. Morph Jahrb
183:1055–64. 14:517–616.
Covey AM, Brody LA, Maluccio MA et al 2002 Variant hepatic arterial Roskams T, Katoonizadeh A, Komuta M 2010 Hepatic progenitor cells: an
anatomy revisited: digital subtraction angiography performed in 600 update. Clin Liver Dis 14:705–18.
patients. Radiology 224:542–7.
Roskams TA, Theise ND, Balabaud C et al 2004 Nomenclature of the finer
Dar FS, Faraj W, Heaton ND et al 2008 Variation in the venous drainage of branches of the biliary tree: canals, ductules, and ductular reactions in
left lateral segment liver graft requiring reconstruction of segment III human livers. Hepatology 39:1739–45.
vein with donor iliac artery. Liver Transpl 14:576–9.
Saba L, Mallarini G 2011 Anatomic variations of arterial liver vascularization:
di Francesco F, Grimaldi C, de Ville de Goyet J 2014 Meso-Rex bypass – a an analysis by using MDCTA. Surg Radiol Anat 33:559–68.
procedure to cure prehepatic portal hypertension: the insight and the
Strasberg SM, Phillips C 2013 Use and dissemination of the Brisbane 2000
inside. J Am Coll Surg 218:e23–36.
nomenclature of liver anatomy and resections. Ann Surg 257:377–82.
Fang CH, You JH, Lau WY et al 2012 Anatomical variations of hepatic veins:


Stringer MD 2009 Eponyms in Surgery and Anatomy of the Liver, Bile Ducts
three-dimensional computed tomography scans of 200 subjects. World
and Pancreas. London: Royal Society of Medicine.
J Surg 36:120–4.
A concise illustrated account of the derivation and individuals behind the
Flament JB, Delattre JF, Hidden G 1982 The mechanisms responsible for more common eponyms associated with liver anatomy and surgery.
stabilising the liver. Anat Clin 4:125–35.
Sugarbaker PH 1990 En bloc resection of hepatic segments 4B, 5 and 6 by
Fraser R, Dobbs BR, Rogers GW 1995 Lipoproteins and the liver sieve: the
transverse hepatectomy. Surg Gynecol Obstet 170:250–2.
role of the fenestrated sinusoidal endothelium in lipoprotein metabo-
lism, atherosclerosis, and cirrhosis. Hepatology 21:863–74. Takasaki K, Koabayashi S, Tanaka S et al 1986 Highly selected hepatic resec-
tion by Glissonian sheath-binding method. Dig Surg 3:121 (abstract).
Goldsmith NA, Woodburne RT 1957 Surgical anatomy pertaining to liver
resection. Surg Gynecol Obstet 195:310–18. Terminology Committee of the International Hepato-Pancreato-Biliary
Association 2000 The Brisbane 2000 terminology of liver anatomy and
Healey JE, Schroy PC 1953 Anatomy of the biliary ducts within the human
resections. HPB 2:333–9.
liver: analysis of the prevailing pattern of branchings and the major
variations of the biliary ducts. Arch Surg 66:599–616. Trutmann M, Sasse D 1994 The lymphatics of the liver. Anat Embryol (Berl)
190:201–9.
Hjortsjö CH 1951 The topography of the intrahepatic duct systems. Acta
Anat (Basel) 11:599–615. Vellar ID, Banting SW, Hardy KJ 1998 The anatomical basis for segment III
cholangiojejunostomy with analysis of 13 cases. Aust N Z J Surg 68:


Hribernik M, Trotovšek B 2014 Intrahepatic venous anastomoses with a
498–503.
focus on the middle hepatic vein anastomoses in normal human livers:
anatomical study on liver corrosion casts. Surg Radiol Anat 36:231–7. Yamamoto M, Katagiri S, Ariizumi S et al 2012 Glissonean pedicle transec-
tion method for liver surgery (with video). J Hepatobiliary Pancreat Sci
Joshi SD, Joshi SS, Athavale SA 2009 Some interesting observations on the
19:3–8.
surface features of the liver and their clinical implications. Singapore
Med J 50:715–19. Yin C, Evason KJ, Asahina K et al 2013 Hepatic stellate cells in liver develop-
ment, regeneration, and cancer. J Clin Invest 123:1902–10.
Lanouis B, Jamieson GG 1993 Modern operative techniques in liver
surgery. Clinical Surgery International 18. Edinburgh: Elsevier, Churchill
Livingstone.


CHAPTER
68
Gallbladder and biliary tree
The biliary tree consists of the system of ducts that collect and The gallbladder is described as having a fundus, body and neck.
deliver bile from the liver to the second part of the duodenum. It is The neck lies at the medial end, close to the porta hepatis, and almost
conventionally divided into intrahepatic and extrahepatic biliary trees. always has a short peritoneal attachment (mesentery) to the liver,
The intrahepatic ducts are formed from bile ductules that join to form which usually contains the cystic artery. The mucosa at the medial
segmental ducts. These merge to form right and left hepatic ducts close end of the neck is obliquely ridged, forming a crescentic fold that is
to the porta hepatis. The extrahepatic biliary tree consists of the extra- continuous with the spirally arranged mucosal folds in the cystic duct
hepatic segments of the right and left hepatic ducts, the common (Dasgupta and Stringer 2005). At its lateral end, the neck widens out
hepatic duct, the cystic duct and gallbladder, and the common bile duct to form the body of the gallbladder; when this widening is clearly
(Fig. 68.1). demarcated as a result of gallstone disease, it is referred to as ‘Hart-
mann’s pouch’. The neck usually lies anterior to the second part of the
duodenum. The body of the gallbladder normally lies in contact with
GALLBLADDER
the visceral surface of the liver. When the neck possesses a mesentery,
this rapidly shortens along the length of the body as it lies in the gall-
The gallbladder is a flask-shaped, blind-ending diverticulum attached bladder fossa. The body lies anterior to the second part of the duode-
to the bile duct by the cystic duct (Fig. 68.2). It stores and concentrates num and the right end of the transverse colon. The bulbous fundus lies
bile. In life, it is grey–blue in colour and is usually firmly attached at the lateral end of the body and usually projects past the inferior
by connective tissue to the inferior surface of the right lobe of the border of the liver to a variable extent. Here, it frequently lies in contact


liver, between segments IV and V at the lower limit of the principal with the anterior abdominal wall behind the ninth costal cartilage,
plane. In the adult, the gallbladder is between 7 and 10 cm long, where the lateral edge of the right rectus abdominis crosses the costal
with a resting volume of about 25 ml and a capacity of up to 50 ml margin. This is where enlargement of the gallbladder is best sought on
(Di Ciaula et al 2012). It usually lies in a shallow fossa (the gallbladder clinical examination. The fundus commonly lies adjacent to the trans-
bed) on the visceral surface of the right lobe of the liver, covered verse colon.
by peritoneum continued from the liver surface. This attachment can The gallbladder varies in size and shape. The fundus may be elon-
vary widely. Rarely, the gallbladder is almost completely buried within gated and highly mobile. Rarely, the fundus is folded back on the body
the liver (intrahepatic gallbladder; Guiteau et al 2009), or suspended of the gallbladder, the so-called Phrygian cap; on ultrasound, this may
from the liver by a peritoneal mesentery (when it is at risk of torsion; be wrongly interpreted as an apparent septum within an otherwise
Gupta et al 2009), or connected to the duodenum by an extension of normal gallbladder. Other anatomical variants of the gallbladder
the free edge of the lesser omentum (cystoduodenal ligament; Ashaolu include duplication, with or without a double cystic duct; agenesis;
et al 2011). internal septation; and an ectopic location (most commonly left-sided)
(Gross 1936, Faure et al 2008); although rare, these congenital anoma-
lies are particularly important if the patient requires surgery for gall-
bladder or gallstone disease (Lamah et al 2001, Singh et al 2006,
Right anterior (medial)
Castorina et al 2014, Chowbey et al 2004).
sectoral duct
VIII
Right posterior (lateral)
V sectoral duct INTRAHEPATIC BILIARY TREE
VII Right hepatic SEGMENTAL AND SECTORAL DUCTS
duct
I
I II


The segmental ducts of the left hemi-liver have a relatively constant
VI
pattern, although more than one segmental duct may drain each
particular segment. The left hepatic duct is formed by the union of
III
segment II and III ducts, most often behind or to the left of the umbili-
IV Left hepatic duct
cal portion of the left portal vein (see Fig. 68.1). The biliary drainage
of segment IV is more variable but is usually by a single duct into the
Common hepatic duct
left hepatic duct. The right hepatic duct is formed by the union of
Cystic duct the right anterior (medial) and posterior (lateral) sectoral ducts. The
right anterior (medial) sectoral bile duct drains segments V and VIII,
Supraduodenal and the right posterior (lateral) sectoral duct drains segments VI and
common bile duct
VII. The right posterior sectoral duct usually curves around the posterior
aspect of the right anterior duct before fusing with its medial aspect;
Retroduodenal
bile duct this is known as Hjortsjö’s crook and is an important technical consid-
eration when performing liver resection (Fig. 68.3). The bile ducts
Retropancreatic draining the caudate lobe (segment I) usually join the origin of the
bile duct left hepatic duct or may drain into both hepatic ducts near the hilar
confluence.
The right hepatic duct and its branches are more often subject to
variation than the left ductal system (Cucchetti et al 2011, Chaib et al
Fig. 68.1 The overall arrangement of the intrahepatic and extrahepatic 2014). These variations have been classified into six main types (Table
biliary tree. The segmental ducts often branch just before they enter the 68.1, Fig. 68.4). Left intrahepatic ductal variations mostly relate to the
main ducts, or are multiple as they enter the main ducts, but for clarity drainage pattern of segment IV; this segmental bile duct usually drains
are shown here as single ducts. Note that segment I often drains via both into the left hepatic duct but it may open into a segment II or III bile
right and left hepatic ducts. The level of the liver parenchyma at the porta duct, the right anterior sectoral duct, or even the common hepatic duct


hepatis is shown by the dashed line. (Chaib et al 2014). 1173


Gallbladder and biliary tree
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An oblique groove on the inferior surface of the liver posterior to
the gallbladder bed is present in 70–80% of livers. It is variably known
as the fissure of Gans, Rouviere’s sulcus or the incisura hepatis dextra
(Ch. 67). It overlies the division of the right posterior (lateral) portal
pedicle, where it gives off the inferior segment VI branch. It has been
increasingly recognized as a useful anatomical landmark during hepatic
resection and in laparoscopic cholecystectomy (since the cystic duct and
artery lie anterosuperior to the sulcus while the common bile duct lies
posteroinferior) (Dahmane et al 2013).


Gallbladder and biliary tree
1174
8
nOitCeS
Neck Cystic duct variants
Body
Cystic duct
V
Fundus
Right and left
hepatic ducts
Common A1 Low entry A2 Medial side entry A3 Common drainage A4 Accessory bile
hepatic duct with right anterior duct (segment V)
sectoral duct draining directly
to gallbladder or
Intrahepatic bile duct variants cystic duct
Spiral II II
folds VIII VIII
I
I
V III V
III
IV
Common VII VII IV
bile duct
VI
VI
Fig. 68.2 The interior of the gallbladder and bile ducts.
Type 1 Normal Type 4 Low drainage of the right posterior
Table 68.1 Major variations of the intrahepatic duct drainage patterns sectoral duct into the common hepatic duct
Type Approximate % Description VIII II VIII II
of population
I I
1 60* Normal anatomy V III V III
2 15 No right hepatic duct. The common hepatic duct is formed by the VII IV VII IV
union of right anterior sectoral, right posterior sectoral and left
hepatic ducts (trifurcation pattern)
3 15 One of the right sectoral ducts (more often the posterior) joins VI VI
the left hepatic duct
4 10 Low drainage of one of the right sectoral ducts (more often the Type 2 Absence of right hepatic duct Rare type. Right posterior sectoral duct
posterior) into the common hepatic duct draining into the cystic duct
Rare <5 The segment V duct or the right posterior sectoral duct drains VIII II
into the cystic duct or gallbladder
I
V III
(Data from Cucchetti et al 2011 and Chaib et al 2014.)
*This figure is higher in men and lower in women, i.e. women are more likely to have variant intrahepatic VII IV
bile duct anatomy. N.B. The percentage of different types varies between populations.
VI
Type 3 Right posterior sectoral duct
draining into the left hepatic duct
EXTRAHEPATIC BILIARY TREE
CYSTIC DUCT Fig. 68.4 Variations in the anatomy of the cystic and intrahepatic bile
ducts. The cystic duct variations are labelled A1–A4 and the intrahepatic


bile duct variations as types 1–4 (see Table 68.1).
The cystic duct drains the gallbladder into the common bile duct. In
adults, it is usually between 2 and 4 cm long and has a luminal diameter
of 2–3 mm (Dasgupta and Stringer 2005). It passes posteriorly and
medially from the neck of the gallbladder, often in a tortuous fashion, rather than regulate the flow of bile, as is commonly stated (Dasgupta
to unite with the common hepatic duct and form the common bile and Stringer 2005).
duct. The anatomy of the junction between the cystic duct and common
hepatic duct is variable (see Fig. 68.4). In most individuals, the cystic
duct joins the middle third of the combined lengths of the common HEPATIC DUCTS
hepatic and common bile ducts (Shaw et al 1993), but it may drain
into the distal common bile duct or into a more proximal duct such as The right and left hepatic ducts emerge from the liver and unite near
the proximal common hepatic duct or right hepatic duct; it usually joins the right end of the porta hepatis to form the common hepatic duct.
the right lateral aspect of the common hepatic duct but may merge The extrahepatic right duct is short (0.5–2.0 cm in adults) and nearly
medially, anteriorly or posteriorly; and it usually forms an oblique vertical, while the left is longer (1.5–3.5 cm) and more horizontal, and
angle with the common hepatic duct but can spiral around it or run lies along the inferior border of segment IV. The accessibility of the
parallel to it in the free edge of the lesser omentum for a variable dis- extrahepatic segment of the left hepatic duct is exploited when perform-
tance before merging (Lamah et al 2001). Irrespective of the site or type ing a surgical biliary bypass in patients with benign hilar bile duct
of union, the terminal part of the cystic duct is frequently adherent to strictures (Myburgh 1993).
the common hepatic duct for a variable distance. In adults, the common hepatic duct descends approximately 3 cm


Rarely, the cystic duct is double or absent (when the gallbladder before being joined obliquely on its right by the cystic duct to form
drains directly into the bile duct), or receives an anomalous hepatic the common bile duct. The common hepatic duct lies to the right of
duct from segment V of the liver. These variations in cystic duct anatomy the hepatic artery and anterior to the portal vein in the free edge of the
are of considerable importance during surgical excision of the gallblad- lesser omentum. In adults, the luminal diameter of the normal common
der (cholecystectomy). The cystic duct must be identified passing to the hepatic duct, as measured by ultrasound, is less than 5 mm.
neck of the gallbladder and must be occluded some distance away from
the bile duct to prevent injury to the latter. A preliminary operative
cholangiogram is essential if the anatomy is unclear or anomalous. COMMON BILE DUCT
The mucosa of the cystic duct has 2–10 crescentic folds that project
into the lumen and form a spiral; these are continuous with those in The common bile duct is formed near the porta hepatis, by the junction
the neck of the gallbladder. The function of these spiral folds is unknown of the cystic and common hepatic ducts (Figs 68.5–68.6). In adults, it
but they may help to preserve the patency of this narrow, tortuous duct is usually between 6 and 8 cm long and its luminal diameter, as


Gallbladder and biliary tree
1174.e1
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retPaHC
A small bile duct from segment V of the liver may traverse the gall- Right anterior (medial)
bladder fossa and join the right hepatic duct or its anterior sectoral sectoral duct Hjortsjö’s crook
branch or the common hepatic duct. This is often known as Luschka’s
duct and its importance lies in the fact that it may be injured during Right posterior (lateral)
cholecystectomy, causing a postoperative bile leak (Spanos and Syrakos sectoral duct
2006). Postmortem studies have identified such a duct in up to one-
third of individuals but many of these are small and relatively insignifi-
cant; if larger ducts (1–2 mm) are considered, the prevalence is nearer
5% (Ko et al 2006). These ducts are more likely to be injured if the
gallbladder is not dissected close to its wall. Luschka did not describe
Left hepatic duct
a duct draining directly into the gallbladder; this is referred to as a
cystohepatic or cholecystohepatic duct and should not be confused
with a hepatocystic duct (which is present when the common bile duct Portal vein
is absent and both hepatic ducts drain directly into the gallbladder Hepatic artery
which drains in turn via the cystic duct into the duodenum) (Losanoff Common hepatic duct
et al 2002).
Fig. 68.3 Hjortsö’s crook. The right posterior (lateral) sectoral bile duct
usually hooks around the right anterior (medial) sectoral pedicle, rendering
it vulnerable to injury when performing an extended left hepatectomy that
includes segments V and VIII of the liver (left trisectionectomy).


extrahepatic biliary tree
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Gallbladder Cystic duct wall of the second part of the duodenum and anterior to the right renal
vein. The posterior superior pancreaticoduodenal branch of the gas-
troduodenal artery descends anterior to the retroduodenal portion of
the common bile duct (at the superior border of the pancreas) before
spiralling around the right side of the bile duct to reach the posterior
surface of the head of the pancreas (Bertelli et al 1996).
Hepatopancreatic ampulla
As it descends behind the head of the pancreas medial to the second
part of the duodenum, the common bile duct approaches the right end
of the pancreatic duct. The two ducts usually enter the duodenal wall
together in a Y configuration to form a short common channel measur-
ing between 2 and 10 mm in length (Flati et al 1994). This common
channel often contains a dilation known as the hepatopancreatic
ampulla (of Vater) and it opens via a single orifice on to the medial
wall of the second part of the duodenum at the major duodenal papilla
(Fig. 68.5B). In clinical practice, the whole region is often termed the
pancreaticobiliary junction. Occasionally, the common bile duct and
pancreatic duct unite outside the duodenal wall to form an abnormally
long common channel or the two ducts are separated by a septum or
drain into the duodenum separately (Kamisawa and Okamoto 2008).
The mucosa of the terminal 5–10 mm of the common bile and pan-
creatic ducts has a complex arrangement of circumferentially arranged
folds (Purvis et al 2013) (Fig. 68.7). Their distribution and orientation
impede reflux of duodenal contents into the bile and pancreatic ducts,
A and they may sometimes cause difficulty cannulating the major duode-
nal papilla during endoscopic retrograde cholangiopancreatography
(ERCP).
Common bile Endoscope Pancreatic
A complex arrangement of smooth muscle with prominent circular
duct duct
fibres surrounds the distal common bile duct (bile duct sphincter) and


Fig. 68.5 A, An endoscopic retrograde cholangiopancreatogram.
hepatopancreatic ampulla (sphincter of Oddi); to a lesser extent, it also
(B, continued online)
surrounds the terminal part of the main pancreatic duct (pancreatic
duct sphincter) (Boyden 1957, Didio and Anderson 1968). The whole
sphincter muscle complex lies mostly within the wall of the duodenum
Gallbladder Right hepatic duct Left hepatic duct Common hepatic duct
and, in adults, measures approximately 15–20 mm in length; it con-
tains a high pressure zone that can be detected by manometry (Teilum
1991, Habib et al 1988). The smooth muscle of the ampullary sphincter
is developmentally and anatomically distinct from the adjacent duo-
denal muscle. The sphincter regulates the flow of bile and pancreatic
secretions into the duodenum and impedes reflux of duodenal contents
into the ductal system (Guelrud et al 1990); it is inhibited by chole-
cystokinin (CCK), which not only relaxes the sphincter but also causes
gallbladder contraction (Woods et al 2005). Division of the upper part
of the ampullary sphincter (sphincterotomy) may be required to allow
access to the common bile duct during ERCP.
The pancreaticobiliary junction is clinically important because it
may be affected by various congenital and acquired disorders. An anom-
alous union between the bile and pancreatic ducts, particularly one
resulting in an abnormally long common channel, may be associated
with congenital bile duct dilation, recurrent pancreatitis, and/or gall-
bladder cancer (Kimura et al 1985, Misra and Dwivedi 1990, Stringer
et al 1995). Acquired pathology in this region also includes gallstone
obstruction and peri-ampullary tumours.
Hepatobiliary triangle
The triangular region formed between the cystic duct, the common
hepatic duct and the inferior surface of the liver is the hepatobiliary
triangle (Fig. 68.8). It is often mistakenly referred to as Calot’s triangle,
which is an isosceles triangle based on the common hepatic duct, with


Duodenum Cystic duct Common bile duct Pancreatic duct the cystic artery and cystic duct forming its sides (Stringer 2009). The
hepatobiliary triangle is bridged by the double layer of peritoneum that
Fig. 68.6 A magnetic resonance cholangiopancreatogram.
forms the short and variable mesentery of the cystic duct. Between these
two layers there is a variable amount of fatty connective tissue, lymphat-
ics, the cystic lymph node, autonomic nerves, and usually the cystic
measured by ultrasound, is no more than 7 mm (Perret et al 2000); the
artery as it runs from the right hepatic artery to the gallbladder; occa-
diameter increases slightly with advancing age from a mean of 3.6 mm
sionally, there may also be an accessory bile duct (see above). Under-
below 60 years to a mean of 4 mm after 80 years. The common bile duct
standing the variations in biliary and arterial anatomy as they relate to
can be divided into supraduodenal, retroduodenal and pancreatic seg-
the triangle is of considerable importance during excision of the gall-
ments. The supraduodenal segment descends posteriorly and slightly
bladder in order to avoid injury to the common hepatic or common
to the left, anterior to the epiploic foramen and inferior vena cava, in
bile duct or right hepatic artery (Suzuki et al 2000, Talpur et al 2010).
the free right border of the lesser omentum, where it lies anterior and
to the right of the portal vein and to the right of the hepatic artery. This
part of the common bile duct is the most accessible at surgery. The
retroduodenal segment lies behind the first part of the duodenum with GALLSTONES
the gastroduodenal artery on its left. The pancreatic segment runs in a
groove on the posterior surface of the head of the pancreas, embedded Gallstones are relatively common and usually form in the gallbladder.
in the gland to a variable degree; it lies up to 2 cm away from the medial Gallbladder contraction may move a gallstone towards the narrow cystic


Gallbladder and biliary tree
1175.e1
86
retPaHC
Undersurface of right Cystic artery Line of common hepatic duct
lobe of the liver
B Endoscopic grasper on Metallic clip across Cystic duct
neck of gallbladder cystic duct
Fig. 68.5 B, Endoscopic image of the major duodenal papilla (arrow) on Fig. 68.8 A view of the hepatobiliary triangle (dashed line) at laparoscopic
the medial wall of the descending duodenum. cholecystectomy. In this patient, the cystic artery can be seen crossing
the triangle superficially en route to the gallbladder. (Courtesy of Richard
Flint, Christchurch Hospital.)
Fig. 68.7 A scanning electron micrograph showing mucosal folds (arrows)
lining the wall the hepatopancreatic ampulla. Abbreviations: I, inferior; L,
lateral; M, medial; S, superior.


Gallbladder and biliary tree
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8
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duct, where it can cause obstruction and pain (biliary colic). If the stone the common hepatic duct within the hepatobiliary triangle, where it
continues to occlude the cystic duct, it will lead to inflammation of the lies superior to the cystic duct. On reaching the superior aspect of the
gallbladder (acute cholecystitis) or a sterile distension of the gallbladder neck of the gallbladder, it divides into a superficial branch that runs
(mucocele); providing the gallbladder has not been inflamed previ- along the peritoneal (inferior) surface of the gallbladder, and a deep
ously, it will be non-fibrotic and distensible, and the fundus often branch that runs between the gallbladder and its fossa; the branches
becomes palpable below the costal margin. A gallstone lodged in the anastomose over the surface of the body and fundus. The cystic artery
cystic duct or neck of the gallbladder may also produce an inflammatory is usually less than 3 mm in diameter, and a larger artery in the
swelling that compresses the common hepatic duct, resulting in partial hepatobiliary triangle is more likely to be the right branch of the
obstruction to the flow of bile and the development of jaundice (the hepatic artery.
so-called ‘Mirizzi syndrome’; Stringer 2009). If the gallstone passes The origin of the cystic artery is variable (Fig. 68.10). The most
through the cystic duct, it may become impacted in the distal common common variant is an origin from the hepatic artery proper, when it
bile duct or at the pancreaticobiliary junction, causing obstructive jaun- often crosses anterior to the common bile duct or common hepatic duct
dice, cholangitis and/or acute pancreatitis. to reach the gallbladder. Rarely, it may arise from the left hepatic, gas-
troduodenal, superior pancreaticoduodenal, coeliac, right gastric or
superior mesenteric arteries; in these cases, the cystic artery may not
ENDOSCOPIC CHOLANGIOPANCREATOGRAPHY traverse the hepatobiliary triangle. The cystic artery frequently bifurcates


close to its origin, giving rise to two vessels. Alternatively, an accessory
The common bile duct and/or pancreatic duct may be accessed endo- cystic artery may arise from the hepatic artery or one of its branches.
scopically from the duodenum for diagnostic cholangiography and/or There appear to be racial differences in the frequency of these variants
pancreatography, and for therapeutic interventions such as the relief of (Saidi et al 2007). Small arterial branches from the parenchyma of
biliary obstruction by insertion of an internal stent. The acute angle segment IV or V of the liver may contribute to the supply of the body
between the distal common bile duct and pancreatic duct may make of the gallbladder, particularly when it is substantially intrahepatic;
direct cannulation of the bile duct difficult. In such cases, the upper these help to protect the gallbladder from ischaemic necrosis if inflam-
part of the major duodenal papilla may be incised (pre-cut sphincter- mation results in thrombosis of the cystic artery.
otomy) to facilitate cannulation of the common bile duct. This incision, The cystic artery also gives rise to multiple fine branches that con-
and the more extensive sphincterotomy that may be performed to tribute to the blood supply of the extrahepatic bile ducts.
release an impacted gallstone (Sakai et al 2012), are occasionally com-
plicated by arterial bleeding. The risk may be reduced by making the ductal arteries
incision in the 10–11 o’clock region of the sphincter (Mirjalili and The common bile duct and hepatic ducts are supplied by a fine network
Stringer 2011). Endoscopic sphincterotomy can result in uncontrolled of arteries arising from several sources. The common bile duct is fre-
reflux of duodenal contents into the distal common bile duct and quently supplied by 2–4 small-calibre arteries that form a long, tortu-
ascending biliary infection. ous, anastomotic network along its length; these narrow vessels tend to
be concentrated at the 3 and 9 o’clock positions around the circumfer-
ence of the duct (Northover and Terblanche 1979). The network is fed
BILIARY DRAINAGE by arteries from the right branch of the hepatic artery above, reinforced


by fine branches from the cystic artery. Branches from three main arte-
The proximity of the fundus of the gallbladder to the anterior abdomi- rial sources often supply the duct from below: the posterior superior
nal wall facilitates ultrasound-guided percutaneous drainage of a dis- pancreaticoduodenal artery, the retroduodenal artery (both of which
tended, obstructed gallbladder. Because of the small calibre of the cystic originate from the gastroduodenal artery and cross anterior to the
duct and its spiral folds, drainage of the gallbladder is rarely sufficient
to decompress the biliary tree when the common bile duct is obstructed.
In such cases, temporary or permanent biliary drainage may be achieved
by the endoscopic insertion of a biliary stent through the obstruction
via the major duodenal papilla, surgical bile diversion, or percutaneous
transhepatic drainage. The latter involves image-guided puncture of a
dilated intrahepatic bile duct and the insertion of an external drain or
an internal stent through the biliary obstruction.
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
Cystic artery
The cystic artery usually arises from the right branch of the hepatic A Hepatic artery proper B Low origin from hepatic artery
artery (Fig. 68.9, but see Fig. 68.10) and most often passes posterior to
Right hepatic artery
Left hepatic artery
Cystic artery
C Gastroduodenal artery D Superior pancreaticoduodenal,
Deep superior branch coeliac or right gastric arteries
Superficial inferior
branch
Hepatic artery ‘proper’
E Left hepatic artery F Multiple cystic arteries
Fig. 68.9 Normal anatomy of the cystic artery. Fig. 68.10 Variant anatomy of the cystic artery.


Microstructure
1177
86
retPaHC
retroduodenal segment of the bile duct), and a retroportal artery arising resembles that of the small intestine. The mucosa is yellowish brown
from the superior mesenteric artery or coeliac trunk and passing to the and elevated into minute rugae with a honeycomb appearance (see Fig.
right on the posterior surface of the portal vein (Chen et al 1999). The 68.2). In section, projections of the mucosa into the gallbladder lumen
supraduodenal segment of the bile duct is relatively less well vascular- resemble intestinal villi, but they are not fixed structures and the surface
ized than the retroduodenal and pancreatic segments, and excessive flattens as the gallbladder fills with bile. The epithelium is a single layer
dissection of this segment may result in an ischaemic bile duct of columnar cells with apical microvilli; basally, the spaces between
stricture. epithelial cells are dilated (Fig. 68.11). Many capillaries lie beneath the
The hilar ducts are supplied by a fine network of periductal arteries basement membrane. The epithelial cells actively absorb water and
that arise from the right and left branches of the hepatic artery and form solutes from the bile and concentrate it up to ten-fold. There are no
an anastomotic plexus within the connective tissue of the hilar plate. goblet cells in the epithelium. The thin fibromuscular layer is composed
The intrahepatic ducts are supplied by segmental branches of the of fibrous tissue mixed with smooth muscle cells arranged loosely in
hepatic artery arising within the Glissonian sheaths (Stapleton et al longitudinal, circular and oblique bundles.
1998, Vellar 1999). The dependence of the intrahepatic bile ducts on
their hepatic arterial blood supply is well recognized in liver transplan-
tation since hepatic artery thrombosis may lead to diffuse intrahepatic BILE DUCTS
biliary strictures despite preservation of portal venous blood flow.
The walls of the large biliary ducts consist of external fibrous and inter-
Cystic veins nal mucosal layers (Fig. 68.12). The outer layer is fibrous connective


The venous drainage of the gallbladder is rarely by a single cystic vein. tissue containing a variable amount of longitudinal, oblique and circu-
There are usually multiple small veins. Those arising from the superior lar smooth muscle cells. The mucosa is continuous with that in the
surface of the body and neck lie in areolar tissue between the gallblad-
der and liver, and drain into segmental portal veins within the liver. The
remainder of the organ drains by one or two small cystic veins into
either portal vein branches within the liver or portal venous tributaries
draining the hepatic ducts and upper bile duct (Sugita et al 2000). Only
rarely does a single or double cystic vein drain directly into the right
branch of the portal vein.
lymphatic drainage
Lymph from the gallbladder and cystic duct drains via several pathways:
to the cystic node, which usually lies above the cystic duct in the hepa-
tobiliary triangle, and from here via nodes in the free edge of the lesser
omentum and along the common hepatic artery to coeliac lymph
nodes; via lymphatics that descend along the common bile duct to the
superior retropancreaticoduodenal node (which communicates with
para-aortic nodes); and directly to superior mesenteric nodes (Sato et al
2013). Lymphatics on the hepatic aspect of the gallbladder connect
directly with intrahepatic lymph vessels.
Lymphatic vessels accompanying the hepatic ducts and upper bile
duct drain to hepatic nodes at the porta hepatis and then via lymph
nodes in the free edge of the lesser omentum to coeliac nodes. Lymphat-
ics from the lower common bile duct also drain to the latter but some
pass directly to retropancreatic and superior mesenteric nodes.
INNERVATION
The gallbladder and the extrahepatic biliary tree are innervated by
branches from the hepatic plexus. Gallbladder contraction occurs in
response to cholecystokinin (CCK) and parasympathetic (vagal) stimu- Fig. 68.11 A low-power micrograph showing the gallbladder wall, with a
mucosal projection that flattens in the full gallbladder, and the thin
lation. Postganglionic sympathetic nerve fibres from the coeliac and
muscular layer.


superior mesenteric ganglia are inhibitory to gallbladder smooth
muscle. Sympathetic afferents from the gallbladder convey pain sensa-
tion; they travel with the greater and lesser splanchnic nerves and have
their cell bodies in the T7–9 spinal cord segments. Visceral pain from
the gallbladder is referred to the right hypochondrium and epigastrium
NN
and may radiate around the back below the right scapula. Inflammation
of the parietal peritoneum overlying the gallbladder produces localized
right upper quadrant pain. A diverse range of neurotransmitters have CC
been identified within intrinsic neurones of the gallbladder (Balemba
et al 2004).
The common bile duct and smooth muscle of the hepatopancreatic
ampulla are also innervated by the vagi, either directly or via the hepatic
plexus, and by sympathetic nerves.
NN
SSMM
MICROSTRUCTURE
GALLBLADDER
MM
The fundus of the gallbladder is completely covered by a serosa, and LL
the inferior surfaces and sides of the body and neck of the gallbladder
are usually covered by a serosa. If the gallbladder possesses a mesentery, Fig. 68.12 A low-power micrograph showing the structure of a human
the serosa extends around the sides of the body and neck on to the common bile duct. Shown are the lumen (L), mucosal lining (M), smooth
superior surface and continues into the serosa of the mesentery, whereas muscle coat (SM) and outer connective tissue (C), with numerous nerve
the serosa is limited to the inferior surfaces only if the gallbladder is fibre bundles (N). (Courtesy of Mr Peter Helliwell and the late Dr Joseph
intrahepatic. Beneath the serosa is subserous loose connective and Mathew, Department of Histopathology, Royal Cornwall Hospitals
adipose peritoneal tissue. The gallbladder wall microstructure generally Trust, UK.)


Gallbladder and biliary tree
1178
8
nOitCeS
hepatic ducts, gallbladder and duodenum. The epithelium is columnar
Bonus e-book images
and there are numerous tubulo-alveolar (or tubulo-acinar) mucous
glands in the duct walls.
Expulsion of gallbladder contents is under neuroendocrine control.
Fat in the duodenum causes the release of CCK by intestinal neuro- Fig. 68.3 Hjortsö’s crook.
endocrine cells, which stimulates the gallbladder to contract because
muscle cells in its walls bear surface receptors for CCK. When the pres- Fig. 68.5 B, Endoscopic image of the major duodenal papilla
sure exceeds 100 mmHO of bile, the sphincter of Oddi relaxes and bile (arrow) on the medial wall of the descending duodenum.
2
enters the duodenum. The termination of the united bile and pancreatic
Fig. 68.7 A scanning electron micrograph showing mucosal folds
ducts is packed with villous, valvular folds of mucosa that contain
lining the wall the hepatopancreatic ampulla.
muscle cells in their connective tissue cores. Contraction is thought to
result in retraction and clumping of these folds, so preventing reflux of
Fig. 68.8 A view of the hepatobiliary triangle at laparoscopic
duodenal contents and controlling the exit of bile.
cholecystectomy.
KEY REFERENCES
Cucchetti A, Peri E, Cescon M et al 2011 Anatomic variations of intrahepatic Stringer MD 2009 Eponyms in Surgery and Anatomy of the Liver, Bile Ducts
bile ducts in a European series and meta-analysis of the literature. and Pancreas. London: Royal Society of Medicine Press.
J Gastrointest Surg 15:623–30. A short reference book that contains illustrated accounts of the original
An analysis of 200 cholangiograms from liver donors, coupled with a descriptions of eponyms cited in this chapter, along with a brief biography of
detailed literature review exploring intrahepatic bile duct anatomy in the person after whom the structure is named.
different racial groups.


Suzuki M, Akaishi S, Rikiyama T et al 2000 Laparoscopic cholecystectomy,
Dasgupta D, Stringer MD 2005 Cystic duct and Heister’s ‘valves’. Clin Anat Calot’s triangle, and variations in cystic arterial supply. Surg Endosc
18:81–7. 14:141–4.
A review of cystic duct anatomy and the significance of its spiral mucosal An article that documents a consecutive series of 244 laparoscopic
folds. cholecystectomies, in which the cystic artery was not present in the
hepatobiliary triangle in 11%, and a further 7% of patients had an
Gross R 1936 Congenital anomalies of gallbladder. A review of one hundred
accessory cystic artery or other arterial variants.
and forty eight cases with a report of double gall-bladder. Arch Surg
32:131–62. Talpur KA, Laghari AA, Yousfani SA et al 2010 Anatomical variations and
A seminal paper on congenital anomalies of the gallbladder. congenital anomalies of extrahepatic biliary system encountered during
laparoscopic cholecystectomy. J Pak Med Assoc 60:89–93.
Lamah M, Karanjia ND, Dickson GH 2001 Anatomical variations of the
An analysis of anatomical variants encountered in 300 adults undergoing
extrahepatic biliary tree: review of the world literature. Clin Anat
cholecystectomy for gallstone disease. Variants were recorded in 20% of
14:167–72.
patients and predominantly involved the cystic artery (11%), cystic duct
A literature review of anatomical variations affecting the extrahepatic bile
(4%), right hepatic artery (3%) and gallbladder (2%).
ducts.


Gallbladder and biliary tree
1178.e1
86
retPaHC
REFERENCES
Ashaolu JO, Ukwenya VO, Adenowo TK 2011 Cystoduodenal ligament as an Losanoff JE, Jones JW, Richman BW et al 2002 Hepaticocystic duct: a rare
abnormal fold and the accompanying anatomical and clinical implica- anomaly of the extrahepatic biliary system. Clin Anat 15:314–15.
tions. Surg Radiol Anat 33:171–4. Mirjalili SA, Stringer MD 2011 The arterial supply of the major duodenal
Balemba OB, Salter MJ, Mawe GM 2004 Innervation of the extrahepatic papilla and its relevance to endoscopic sphincterotomy. Endoscopy
biliary tract. Anat Rec A Discov Mol Cell Evol Biol 280:836–47. 43:307–11.
Bertelli E, Di Gregorio F, Bertelli L et al 1996 The arterial blood supply of Misra SP, Dwivedi M 1990 Pancreaticobiliary ductal union. Gut 31:
the pancreas: a review. II. The posterior superior pancreaticoduodenal 1144–9.
artery. An anatomical and radiological study. Surg Radiol Anat 18:1–9. Myburgh JA 1993 The Hepp–Couinaud approach to strictures of the bile
Boyden EA 1957 The anatomy of the choledochoduodenal junction in man. ducts. I. Injuries, choledochal cysts, and pancreatitis. Ann Surg
Surg Gynecol Obstet 104:640–52. 218:615–20.
Castorina S, Scilletta R, Domergue J 2014 Gallbladder agenesis: laparoscopic Northover JMA, Terblanche J 1979 A new look at the arterial supply
views of a significant diagnostic challenge. Surg Radiol Anat 36: of the bile duct in man and its surgical implications. Br J Surg 66:
619–20. 379–84.
Chaib E, Kanas AF, Galvão FH et al 2014 Bile duct confluence: anatomic Perret RS, Sloop GD, Borne JA 2000 Common bile duct measurements in


variations and its classification. Surg Radiol Anat 36:105–9. an elderly population. J Ultrasound Med 19:727–30.
Chen WJ, Ying DJ, Liu ZJ et al 1999 Analysis of the arterial supply of Purvis NS, Mirjalili SA, Stringer MD 2013 The mucosal folds at the pancrea-
the extrahepatic bile ducts and its clinical significance. Clin Anat ticobiliary junction. Surg Radiol Anat 35:943–50.
12:245–9. Saidi H, Karanja TM, Ogengo JA 2007 Variant anatomy of the cystic artery
Chowbey PK, Wadhwa A, Sharma A et al 2004 Ectopic gallbladder: laparo- in adult Kenyans. Clin Anat 20:943–5.
scopic cholecystectomy. Surg Laparosc Endosc Percutan Tech 14:26–8. Sakai Y, Tsuyuguchi T, Sugiyama H et al 2012 Current situation of endo-
Cucchetti A, Peri E, Cescon M et al 2011 Anatomic variations of intrahepatic scopic treatment for common bile duct stones. Hepatogastroenterol
bile ducts in a European series and meta-analysis of the literature. 59:1712–16.
J Gastrointest Surg 15:623–30. Sato T, Ito M, Sakamoto H 2013 Pictorial dissection review of the lymphatic
An analysis of 200 cholangiograms from liver donors, coupled with a pathways from the gallbladder to the abdominal para-aortic lymph
detailed literature review exploring intrahepatic bile duct anatomy in nodes and their relationships to the surrounding structures. Surg Radiol
different ethnic groups. Anat 35:615–21.
Dahmane R, Morjane A, Starc A 2013 Anatomy and surgical relevance Shaw MJ, Dorsher PJ, Vennes JA 1993 Cystic duct anatomy: an endoscopic
of Rouviere’s sulcus. Scientific World Journal 2013:254287. doi: perspective. Am J Gastroenterol 88:2102–6.
10.1155/2013/254287. Singh B, Ramsaroop L, Allopi L et al 2006 Duplicate gallbladder: an unusual


Dasgupta D, Stringer MD 2005 Cystic duct and Heister’s ‘valves’. Clin Anat case report. Surg Radiol Anat 28:654–7.
18:81–7. Spanos CP, Syrakos T 2006 Bile leaks from the duct of Luschka (subvesical
A review of cystic duct anatomy and the significance of its spiral mucosal duct): a review. Langenbecks Arch Surg 391:441–7.
folds.
Stapleton GN, Hickman R, Terblanche J 1998 Blood supply of the right and
Di Ciaula A, Wang DQ, Portincasa P 2012 Gallbladder and gastric motility left hepatic ducts. Br J Surg 85:202–7.
in obese newborns, pre-adolescents and adults. J Gastroenterol Hepatol Stringer MD 2009 Eponyms in Surgery and Anatomy of the Liver, Bile Ducts
27:1298–305. and Pancreas. London: Royal Society of Medicine Press.
Didio JA, Anderson MC 1968 Biliary and Pancreatic Ducts: The ‘Sphincters’ A short reference book that contains illustrated accounts of the original
of the Digestive System. Baltimore: Williams & Wilkins, pp. 129–51. descriptions of eponyms cited in this chapter, along with a brief biography of
Faure JP, Doucet C, Scepi M et al 2008 Abnormalities of the gallbladder, the person after whom the structure is named.
clinical effects. Surg Radiol Anat 30:285–90. Stringer MD, Dhawan A, Davenport M et al 1995 Choledochal cysts: lessons
Flati G, Flati D, Porowska B et al 1994 Surgical anatomy of the papilla of from a 20 year experience. Arch Dis Child 73:528–31.
Vater and the biliopancreatic ducts. Am Surg 60:712–18. Sugita M, Ryu M, Satake M et al 2000 Intrahepatic inflow areas of the
Gross R 1936 Congenital anomalies of gallbladder. A review of one hundred drainage vein of the gallbladder: analysis by angio-CT. Surgery 128:


and forty eight cases with a report of double gall-bladder. Arch Surg 417–21.
32:131–62. Suzuki M, Akaishi S, Rikiyama T et al 2000 Laparoscopic cholecystectomy,
A seminal paper on congenital anomalies of the gallbladder. Calot’s triangle, and variations in cystic arterial supply. Surg Endosc
Guelrud M, Mendoza S, Rossiter G et al 1990 Sphincter of Oddi manometry 14:141–4.
in healthy volunteers. Dig Dis Sci 35:38–46. An article that documents a consecutive series of 244 laparoscopic
cholecystectomies, in which the cystic artery was not present in the
Guiteau JJ, Fisher M, Cotton RT et al 2009 Intrahepatic gallbladder. J Am
hepatobiliary triangle in 11%, and a further 7% of patients had an
Coll Surg 209:672.
accessory cystic artery or other arterial variants.
Gupta V, Singh V, Sewkani A et al 2009 Torsion of gall bladder, a rare entity:
a case report and review article. Cases J 2:193. Talpur KA, Laghari AA, Yousfani SA et al 2010 Anatomical variations and
congenital anomalies of extrahepatic biliary system encountered during
Habib FI, Corazziari E, Biliotti D et al 1988 Manometric measurement of laparoscopic cholecystectomy. J Pak Med Assoc 60:89–93.
human sphincter of Oddi length. Gut 29:121–5.
An analysis of anatomical variants encountered in 300 adults undergoing
Kamisawa T, Okamoto A 2008 Pancreatographic investigation of pancreatic cholecystectomy for gallstone disease. Variants were recorded in 20% of
duct system and pancreaticobiliary malformation. J Anat 212:125–34. patients and predominantly involved the cystic artery (11%), cystic duct
Kimura K, Ohto M, Saisho H et al 1985 Association of gallbladder carci- (4%), right hepatic artery (3%) and gallbladder (2%). Anatomical
noma and anomalous pancreaticobiliary ductal union. Gastroenterol variants were associated with a slightly increased incidence of postoperative


89:1258–65. morbidity.
Ko K, Kamiya J, Nagino M et al 2006 A study of the subvesical bile duct Teilum D 1991 In vitro measurement of the length of the sphincter of Oddi.
(duct of Luschka) in resected liver specimens. World J Surg Endoscopy 23:114–6.
30:1316–20.
Vellar ID 1999 The blood supply of the biliary ductal system and its rele-
Lamah M, Karanjia ND, Dickson GH 2001 Anatomical variations of the vance to vasculobiliary injuries following cholecystectomy. Aust N Z J
extrahepatic biliary tree: review of the world literature. Clin Anat Surg 69:816–20.
14:167–72.
Woods CM, Mawe GM, Toouli J et al 2005 The sphincter of Oddi:
A literature review of anatomical variations affecting the extrahepatic bile
understanding its control and function. Neurogastroenterol Motil
ducts.
17:31–40.


CHAPTER
69
Pancreas
The pancreas is one of the largest digestive glands. The major part of duodenum and is continuous with the uncinate process. The anterior
the gland is exocrine, secreting enzymes involved in the digestion of surface of the head is covered by peritoneum and related to the origin
lipids, carbohydrates and proteins. It has an additional endocrine func- of the transverse mesocolon (Fig. 69.3B). Posteriorly, the common bile
tion derived from clusters of cells scattered throughout the substance duct is partially embedded within the head of the gland just proximal
of the gland, which take part in glucose homeostasis and the control to where it joins the pancreatic duct near the major duodenal papilla
of upper gastrointestinal motility and function. (Burgard et al 1991, Nagai 2003). The posterior surface of the pancreatic
The healthy pancreas is creamy pink in colour, with a soft to head is also related to the inferior vena cava, the right crus of the dia-
firm consistency and lobulated surface. It is divided into a head, neck, phragm and the termination of the right gonadal vein (Ch. 76; see Fig.
body, tail and uncinate process on the basis of its anatomical relations 76.5). Near the midline, the head of the pancreas becomes continuous
(Figs 69.1–69.3A). In adults, the gland measures 12–15 cm in length with the neck.
and is shaped as a flattened ‘tongue’ of tissue lying in the retroperito-
neum, thicker at its medial end (head) and thinner towards the lateral
end (tail). The head lies within the ‘C’ loop of the duodenum and the NECK
remainder of the gland extends transversely and slightly cranially across
the retroperitoneum and posterior to the stomach to the hilum of the The neck of the pancreas is approximately 2 cm wide and links the head
spleen. It is ‘draped’ over the vertebral column and other retroperitoneal and body. It is often the most anterior part of the gland and may be
structures, forming a distinct shallow curve, with the neck and medial defined as that part of the pancreas lying anterior to the formation of


body lying most anteriorly. In adults, it has an average volume of the portal vein (usually the union of the superior mesenteric and
70–80 cm3, although this varies considerably between individuals (with splenic veins) in the transpyloric plane (Fig. 69.4D,E). This is a crucial
a range of 40–170 cm3) and tends to be greater in males (Djuric- relationship when evaluating pancreatic cancer because malignant
Stefanovic et al 2012). Pancreatic volume increases with age, to reach a involvement of these vessels may make resection impossible. The supe-
peak in the fourth decade. From about 60 years of age, the gland atro- rior mesenteric vein and portal vein groove the posterior aspect of the
phies and fatty connective tissue replaces exocrine tissue (Caglar et al neck. The inferior mesenteric vein joins the confluence of the superior
2012, Saisho et al 2007). mesenteric vein and splenic vein in one-third of individuals (Kimura
The ventral surface of the pancreas is covered by parietal peritoneum 2000; see Fig. 69.7). The anterior surface of the pancreatic neck is
and is crossed by the root of the transverse mesocolon. A loose connec- covered by peritoneum and lies adjacent to the pylorus. The anterior
tive tissue layer immediately posterior to the pancreas, sometimes superior pancreaticoduodenal branch of the gastroduodenal artery
known the fusion fascia of Treitz in the region of the pancreatic head descends in front of the gland at the junction of the head and neck.
and the fusion fascia of Toldt in the region of the body and tail, contains
vessels that supply the pancreas (Kimura 2000).
BODY
HEAD The body of the pancreas is the longest part of the gland and runs from
the neck to the tail, becoming progressively thinner. It is slightly trian-
The head of the pancreas lies to the right of the midline, anterior gular in cross-section, and has anterior and posterior surfaces and supe-
and to the right of the vertebral column, within the curve of the duo- rior and inferior borders.
denum. It is the thickest and broadest part of the pancreas but is still


flattened in the anteroposterior plane. Superiorly, it lies adjacent to the Anterior surface The anterior surface is covered by peritoneum,
first part of the duodenum; close to the pylorus, however, where the which is reflected anteroinferiorly from the surface of the gland to
duodenum is on a short mesentery, it overlaps the upper part of be continuous with the posterior layer of the greater omentum and
the head anteriorly. The duodenal border of the head is flattened, the transverse mesocolon (see Fig. 63.4). The two layers of the trans-
slightly concave and adherent to the second part of the duodenum, verse mesocolon diverge along this surface (see Fig. 69.3B). Above the
particularly around the duodenal papillae. The superior and inferior attachment of the transverse mesocolon, the anterior surface of the
pancreaticoduodenal arteries lie adjacent to this region. The inferior pancreas is separated from the stomach by the lesser sac. Inferiorly, it
border of the pancreatic head lies superior to the third part of the lies within the infracolic compartment, and its anterior relations include
Inferior vena cava
Tail
Bile duct
Body
Left kidney
Duodenum Neck
Main pancreatic duct
Accessory pancreatic duct Head
Superior mesenteric artery
Superior mesenteric vein
Uncinate process
Hepatopancreatic ampulla
Fig. 69.1 Relations of the pancreas. 1179


Pancreas
1180
8
nOITces
the fourth part of the duodenum, the duodenojejunal flexure and coils
of jejunum. Tail
Posterior surface The posterior surface of the pancreas is devoid of
A
peritoneum. It lies on fascia (the fusion fascia of Toldt) anterior
to the aorta and the origin of the superior mesenteric artery, the left
Body
crus of the diaphragm, left suprarenal gland, the upper pole of the left
kidney surrounded by perirenal fascia, and left renal vein (Kimura
2000; see Figs 69.1, 69.4A–G). The splenic vein runs from left to right Neck
directly on this surface of the gland and indents the parenchyma to a
variable extent, ranging from a shallow groove to almost a tunnel.
Superior border To the right, the superior border of the body of the
Head
pancreas is blunt but it becomes narrower and sharper to the left. An
Uncinate
process
Spleen
(anterior border)
Body of pancreas Tail of pancreas
Liver Portal vein Pancreatic duct Stomach Spleen
B
Body
Pylorus
D1 Antrum
Jejunal loops
Attachment of the leaves
of the transverse mesocolon
Attachment of the leaves
Proximal transverse
of the greater omentum
colon
SMV SMA
Ileal loops
Fig. 69.3 A, Regions and anterior surfaces and borders of the pancreas.
Head of pancreas Jejunum B, Anterior relations of the pancreas. Areas covered in peritoneum are
shown in blue and structures overlying these areas are separated from
Second part of duodenum Neck of pancreas Left kidney
the pancreas by peritoneal ‘spaces’. The spleen lies anterior to the
Fig. 69.2 A coronal reformat computed tomogram (CT) of the pancreas anterior leaf of the splenorenal ligament and not in direct contact
showing its relations in the upper abdomen. (Courtesy of the Department with pancreatic tissue. Abbreviations: D1, first part of the duodenum;
of Radiology, Global Hospital, Chennai, India.) SMA, superior mesenteric artery; SMV, superior mesenteric vein.
Neck of pancreas Duodenum (fourth part)


Inferior vena cava Head of pancreas Superior mesenteric vein
A
F
D
B
B
Superior
mesenteric vein Superior
mesenteric artery
Duodenum Uncinate process
(second part)
Duodenum
Inferior vena cava (fourth part)
Aorta Gonadal arteries
Inferior pole of
left kidney C
Duodenum (second part) Aorta
Uncinate process Superior mesenteric artery
Fig. 69.4 A, Posterior relations of the pancreas, with planes of section labelled as shown in B, D and F. B, Diagrammatic cross-section taken at the mid
level of the uncinate process, and equivalent CT axial slice (C).
Continued


Pancreas
1181
96
reTPaHc
Superior mesenteric vein Body of pancreas
Duodenum (second part) Neck of pancreas Splenic vein
D
Neck and body
of pancreas Portal vein
Duodenum Superior
(second part) mesenteric artery
Splenic vein
Inferior vena cava Left renal vein
Aorta Left crus
Left kidney
E
Inferior vena cava Left renal vein Superior mesenteric artery
Coeliac trunk Body of pancreas Stomach Tail of pancreas
F
Origin of
coeliac trunk Tail of pancreas
Inferior vena cava
Splenic
Aorta vein
Spleen
Left
kidney
G
Inferior vena cava Aorta Splenic vein
Upper pole of left kidney Spleen
Fig. 69.4, cont’d Diagrammatic cross-sections and equivalent CT axial slices taken at the head and neck (D–E), and tail (F–G) of the pancreas.
omental tuberosity usually projects from the right end of the superior ligament. It may terminate at the base of the splenorenal ligament or
border above the level of the lesser curvature of the stomach. The supe- extend up to the splenic hilum, when it is at risk of injury at splenec-
rior border is related to the coeliac artery and its branches; the common tomy during ligation or stapling of the splenic vessels. The splenic artery
hepatic artery runs to the right just above the gland, and the splenic and its branches, and the splenic vein and its tributaries, lie posterior
artery passes to the left in a tortuous manner, projecting above the to the tail (see Fig. 69.4F,G).
superior border at several points.
Inferior border At the medial end of the inferior border, adjacent to
the neck of the pancreas, the superior mesenteric vessels emerge from UNCINATE PROCESS
behind the gland. Laterally, the inferior mesenteric vein runs behind
the inferior border to join the splenic vein or the confluence of the The uncinate process is a hook-shaped continuation of the inferomedial
splenic and superior mesenteric veins. This is a useful site for identifica- part of the head of the gland. Embryologically, it is separate from the


tion of the inferior mesenteric vein on computed tomographic (CT) rest of the gland (p. 1051). The superior mesenteric vein and, occasion-
imaging and during left-sided colonic resections. ally, the superior mesenteric artery descend on its anterior surface before
running forwards into the root of the mesentery of the small intestine.
The uncinate process extends medially anterior to the abdominal aorta
TAIL above the third part of the duodenum, which may be compressed by a
pancreatic tumour at this site. On sagittal cross-sectional imaging, the
The tail of the pancreas is the narrowest, most lateral portion of the left renal vein, uncinate process, and third part of duodenum can be
gland and is continuous medially with the body. It is between 1.5 and seen lying between the superior mesenteric artery anteriorly and the
3.5 cm long in adults and lies between the layers of the splenorenal abdominal aorta posteriorly.


Pancreas
1182
8
nOITces
A in calibre within the body of the gland as it receives further lobular
ducts that join it almost at right angles to its axis, forming a ‘herring-
bone pattern’. In adults, the duct can often be demonstrated on ultra-
Accessory duct sound, measuring approximately 3 mm in diameter in the head, 2 mm
in the body and 1 mm in the tail; the calibre of the duct increases from
Main duct about the fifth decade onwards (Glaser et al 1987). As it reaches the
neck of the gland, it turns inferiorly and posteriorly towards the
bile duct, which lies on its right side. The two ducts unite to form a
short common channel, which enters the wall of the descending part
of the duodenum obliquely; it may contain a dilation known as the
hepatopancreatic ampulla (of Vater) (p. 1175). The terminal part of the
main pancreatic duct contains a few mucosal folds that impede reflux
of pancreatic juice (Purvis et al 2013). The length of the common pan-
B creaticobiliary channel is variable and measures up to 5–7 mm in
normal individuals (Horaguchi et al 2014).
The accessory (dorsal) pancreatic duct (of Santorini) drains the
upper part of the anterior portion of the pancreatic head. Much smaller
Accessory duct
in calibre than the main duct, it is formed within the substance of the
Main duct head from several lobular ducts and usually communicates with the
main pancreatic duct near the neck of the gland or near its first inferior
branch (Kamisawa and Okamoto 2008, Kamisawa 2004). The accessory
duct usually opens on to a small, rounded minor duodenal papilla,
which lies about 2 cm proximal to the major papilla (see Fig. 69.5A).
If the duodenal end of the accessory duct fails to develop, the lobular
ducts drain via small channel(s) into the main duct (Hernandez-Jover
et al 2011). The anatomy of the main and accessory pancreatic ducts
may vary, reflecting anomalies in the development and fusion of the
C
dorsal and ventral pancreatic ducts.
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
Main duct
Arteries


The pancreas has a rich arterial supply via branches from the coeliac
trunk and superior mesenteric artery (Figs 69.6A–C; see also Fig. 65.4).
The head and adjoining duodenum are supplied mainly by four arter-
ies: two from the coeliac trunk via the gastroduodenal artery (anterior
and posterior superior pancreaticoduodenal arteries), and two from the
superior mesenteric artery via the inferior pancreaticoduodenal artery
(anterior and posterior inferior pancreaticoduodenal arteries). The two
D anterior arteries supply the ventral aspects of the duodenum, pancreatic
head and uncinate process, and join to form the anterior pancreati-
coduodenal arcade. The two posterior arteries supply the dorsal aspect
of the pancreatic head, adjacent duodenum and distal bile duct, and
may join to form a posterior pancreaticoduodenal arcade.
Main duct The body and tail of the pancreas are supplied by multiple branches
from the splenic artery, including the dorsal pancreatic artery. Small
arteries characteristically run along the superior and inferior borders of
the gland, lying in a deep groove or within the parenchyma. They are
fed along their length by the pancreaticoduodenal and splenic arteries.
Bleeding from these vessels is avoided by ligating the upper and lower
borders of the pancreas prior to transection.
Posterior superior pancreaticoduodenal artery
Fig. 69.5 Variations in the ductal anatomy of the pancreas. A, Normal. The posterior superior pancreaticoduodenal artery usually arises as the
The main pancreatic duct is formed by fusion of the dorsal and ventral first branch of the gastroduodenal artery at the superior edge of the first
bud ducts, and communicates with the accessory pancreatic duct. part of the duodenum. It runs to the right, anterior to the supraduode-
B, Normal. There is no communication between the main duct and nal portion of the bile duct, before spiralling posteriorly around the
a normally sited accessory duct. C, Pancreas divisum. The majority common bile duct and descending on the posterior surface of the pan-
of the pancreas drains via a dominant dorsal duct that enters the creatic head. It gives branches to the duodenum, head of the pancreas,


duodenum at the minor papilla. A short ventral duct is seen draining, and bile duct before anastomosing with the posterior inferior pancrea-
along with the bile duct, into the major duodenal papilla. D, Absence of
ticoduodenal artery to form the posterior pancreaticoduodenal arcade.
accessory duct. (E–G, continued online)
The posterior superior pancreaticoduodenal artery may also give origin
to the retroduodenal and supraduodenal arteries, which supply the
duodenum (Bertelli et al 1996a). The spiral course of the posterior
superior pancreaticoduodenal artery reflects its embryonic develop-
ment: it is the artery to the anterior aspect of the ventral pancreatic bud
PANCREATIC DUCTS and the bile duct, which subsequently rotate clockwise behind the
duodenum and dorsal pancreatic bud (Bertelli et al 1997).
The exocrine pancreatic tissue drains into multiple small lobular ducts.
The arrangement of the main ducts draining the pancreas is subject to anterior superior pancreaticoduodenal artery
variation but the most common arrangement is a single main and a The anterior superior pancreaticoduodenal artery usually arises as the
single accessory duct (Fig. 69.5). This arrangement reflects the embryo- smaller terminal branch of the gastroduodenal artery, together with the
logical development of the dorsal and ventral pancreatic ducts (p. 1051; right gastroepiploic artery. It originates behind the first part of the duo-
see Figs 60.3–60.4). The main pancreatic duct (of Wirsung) usually runs denum and runs inferiorly on the anterior aspect of the pancreatic head
within the substance of the gland from left to right. It lies midway at a variable distance medial to the groove between the descending
between the superior and inferior borders of the pancreas, usually duodenum and pancreatic head. It passes inferiorly around the right or
slightly more towards the posterior surface of the gland. It is formed by inferior border of the pancreatic head, often piercing the gland to reach
the junction of several lobular (secondary) ducts in the tail and increases the posterior surface of the uncinate process, where it joins the anterior


Pancreas
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An abnormally long common channel may occur in isolation or
with congenital choledochal dilation, and is associated with pancreatico-
biliary reflux and an increased risk of gallbladder cancer (Kamisawa
et al 2010a).
Patients who develop acute pancreatitis are more likely to have a
poorly developed minor papilla; if this were not so, the patent accessory
duct system might act as a secondary drainage mechanism for the main
ductal system and so prevent elevation of intraductal pressures likely to
cause acute pancreatitis (Kamisawa et al 2010b). One clinically impor-
tant variation is ‘pancreas divisum’, seen in 5–10% of individuals (Rana
et al 2012; see Fig. 69.5C, G). In this condition, there is a failure of
normal duct fusion and the accessory pancreatic duct drains the entire
pancreas via the minor papilla, except that part of the head and unci-
nate process that develop from the ventral bud. The relatively small size
of the minor papilla might impair pancreatic drainage, leading to recur-
rent pancreatitis.
Catheter in Bile duct Pancreatic duct
cystic duct (dorsal duct origin) Pancreatic duct (dorsal duct origin)
F
E Common bile duct Major duodenal Pancreatic duct Area of fusion of embryonic
papilla (ventral duct origin) dorsal and ventral ducts
Accessory pancreatic duct Pancreatic duct
(dorsal duct origin) (ventral duct portion)
Minor duodenal papilla Gallbladder Dorsal pancreatic duct Interconnecting channel
G
Duodenum Biliopancreatic channel
Common bile duct Major duodenal papilla
Ventral pancreatic duct
Fig. 69.5, cont’d Variations in the ductal anatomy of the pancreas. E, Intraoperative cholangiogram visualizing the main pancreatic duct opening into the
duodenum through the major duodenal papilla, the accessory duct opening through the minor duodenal papilla and its communicating branch. F, Normal
magnetic resonance cholangiopancreatogram (MRCP). The dorsal duct joins with the distal ventral duct in the head of the pancreas. G, Pancreas


divisum. MRCP reconstruction shows that the dorsal duct is dominant and enters the duodenum at the minor duodenal papilla. A short ventral
pancreatic duct is seen draining with the bile duct into the major papilla.(Figs 69.5E–G, courtesy of Mohamed Rela, Global Hospitals, Chennai, India.)


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A
Right gastroepiploic artery Splenic artery
Gastroduodenal artery
Arteria caudae pancreatis
(Artery to the tail of the pancreas)
Posterior superior
pancreaticoduodenal artery Arteria pancreatica magna
(Greater pancreatic artery)
Left branch, dorsal pancreatic artery
Anterior superior
pancreaticoduodenal artery Right branch, dorsal pancreatic artery
Jejunal branches
Anterior inferior
pancreaticoduodenal artery
Posterior inferior
pancreaticoduodenal artery
Superior mesenteric artery
RHA GDA LGA PB C
LHA CHA SA Gastroduodenal artery Bile duct
Communicating artery
Duodenum
Pancreatic duct
B
Inferior pancreaticoduodenal
PSPD RGE PIPD First jejunal TPA
ASPD AIPD IPD artery DPA Anterior superior artery
Superior mesenteric artery
pancreaticoduodenal
artery Posterior pancreaticoduodenal arcade
Anterior pancreaticoduodenal arcade
Fig. 69.6 A, The arterial supply of the pancreas. B, A CT angiographic reconstruction. The black arrow shows the coeliac trunk, and the white arrow
shows the superior mesenteric artery. Anastomotic arcades, both ventral and dorsal, can be seen coursing around the head of the pancreas. The body
and tail of the pancreas are supplied by multiple pancreatic branches (PB) from the splenic artery and the dorsal pancreatic artery (DPA), which, in this
example, arises from the superior mesenteric artery, and gives origin to the transverse pancreatic artery (TPA). Other abbreviations: AIPD, anterior inferior
pancreaticoduodenal artery; ASPD, anterior superior pancreaticoduodenal artery; CHA, common hepatic artery; GDA, gastroduodenal artery; IPD, inferior
pancreaticoduodenal artery; LGA, left gastric artery; LHA, left hepatic artery; PIPD, posterior inferior pancreaticoduodenal artery; PSPD, posterior
superior pancreaticoduodenal artery; RGE, right gastroepiploic artery; RHA, right hepatic artery; SA, splenic artery. C, The anterior and posterior


pancreaticoduodenal arterial arcades and a typical communicating artery. (Adapted with permission from Mirjalili SA, Stringer MD. The arterial supply of
the major duodenal papilla and its relevance to endoscopic sphincterotomy. Endoscopy 2011; 43(4): 307–11.)
inferior pancreaticoduodenal artery to form the anterior pancreaticoduo- artery gives off a jejunal branch and then runs posterior to both the
denal arcade (Bertelli et al 1995). superior mesenteric artery and vein before dividing into its terminal
branches. Occasionally, the inferior pancreaticoduodenal artery is
Inferior pancreaticoduodenal artery absent and the anterior and posterior inferior pancreaticoduodenal
An inferior pancreaticoduodenal artery is present in most individuals. arteries arise separately from the superior mesenteric artery.
It usually arises either directly from the superior mesenteric artery at The smaller anterior inferior pancreaticoduodenal artery runs to the
the inferior border of the pancreas or as a common vessel with the first right on the posterior surface of the uncinate process to join the anterior
jejunal artery (a pancreaticoduodenojejunal trunk) from the posterior superior pancreaticoduodenal artery and form the anterior pancreati-
or left aspect of the superior mesenteric artery (Horiguchi et al 2008, coduodenal arcade. The larger posterior inferior pancreaticoduodenal
Bertelli et al 1996b). It runs to the right, posterior to the superior artery runs on the posterior surface of the head of the pancreas, parallel
mesenteric vein, to reach the posterior surface of the uncinate process, and superior to the anterior inferior pancreaticoduodenal artery. It joins
where it divides into anterior and posterior inferior pancreaticoduode- the posterior superior pancreaticoduodenal artery to form the posterior
nal arteries. When arising as a pancreaticoduodenojejunal trunk, the pancreaticoduodenal arcade (Bertelli et al 1997).