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G. B. , gall-bladder, which was full of bile.

commencement of the duodenum, and when these are distended they impress upon
the surface of the quadrate lobe a slight concavity. It is bounded on the left by
the umbilical fissure, and behind by the transverse or portal fissure.

The right surface is convex from before backwards, and often slightly
convex from above downwards. It unites with the upper, anterior, and posterior
surfaces by rounded borders, but is separated below from the under surface by a
sharp edge.

Fissures. The transverse or portal fissure (fig. 147, p) is the most important,
because it is here that the great vessels and nerves enter, and the hepatic duct
passes out. It lies transversely between the quadrate lobe in front and the caudate
and Spigelian lobes behind, and meets the longitudinal fissure nearly at right angles.

The longitudinal fissure, between the right and the left lobes, is divided into two
parts by its junction with the transverse fissure. The anterior part (u.f.), named



THE LIVER. 125

the umbilical fissure, contains the umbilical vein in the foetus, and the remnant of
that vein in the adult, which then constitutes the round ligament. Itliei between
the quadrate and left lobes of the liver, the substance of which often forms a bridge
( pons hepatis) across the fissure, so as to convert it partially or completely into a
canal. The posterior part (f.d. ?'.) is named the fissure of the duct us venosus ; it is
situated between the lobe of Spigelius and the left lobe, and lodges the ductus
venosus in the foetus, and in the adult a sbnder cord or ligament into which that
vein is converted.

The fissure or fossa of the vena cava (v. c. i.) is situated at the back of the liver
between the Spigelian lobe and the right lobe, and is separated from the transverse
fissuie by the caudate lobe. It is at the upper part of this fossa that the blood
leaves the liver by the hepatic veins, which end here in the vena cava. As in the
case of the umbilical fissure, the substance of the liver in some cases unites around
the vena cava, and encloses that vessel in a canal.

The transverse and umbilical fissures are on the under surface of the liver ; the
fissure of the ductus venosus and that for the vena cava are on the posterior
surface.

Ligaments and Omentum. Ihe ligaments of the liver are, with one
exception, only reflections of serous membrane. Thus the name coronary ligament is
given to the reflection of peritoneum around the somewhat triangular portion of the
posterior surface of the liver (fig. 147, X), which is here immediately adherent to the
diaphragm. These reflections are continued at either end into a fold the right
and left lateral ligaments, of which the left is the longer and more distinct, the right
being sometimes scarcely perceptible. Another of these so-called ligaments is the
falciform,, broad, or suspensory ligament, a wide thin membrane, formed of two
cohering layers of peritoneum continuous behind with the upper layer of the
coronary and left lateral ligament respectively. By one of its margins it is
connected with the under surface of the diaphragm, and with the sheath of the
right rectus muscle of the abdomen as low as the umbilicus ; by another it is
attached along the upper and anterior surfaces of the liver ; the remaining margin is
free, and contains between its layers the round ligament, a dense fibrous cord, the
remnant of the umbilical vein of the foetus, which ascends from the umbilicus
within the lower edge of the falciform ligament, and enters the longitudinal fissure
on the under surface.

In addition to the folds called ligaments, the liver gives attachment to two kyers
of peritoneum, which pass between the liver and stomach, and form the gastro-
hepatic or lesser omentum. This is attached to the transverse fissure of the liver,
and the posterior part of the longitudinal fissure, or the fissure of the ductus
venosus, and near its right free border encloses between its two layers the bile-duct,
portal vein, hepatic artery, lymphatics, and nerves.

Position with regard to the abdominal and thoracic parietes. The
liver occupies the right hypochondriac and epigastric regions, extending also
frequently into the left hypochondriac and right lumbar. In almost the whole ot
its extent it is separated from the surface of the body by the lower ribs and costal
cartilages, but in the subcostal angle a small part of the anterior surface lies directly
behind the abdominal wall. Above it is accurately adapted to the vault of the
diaphragm, and the right lobe reaches higher beneath the ribs than the left,
corresponding thus with the more elevated position of the diaphragm on the right
side. The liver is separated by the diaphragm from the concave base of the right
lung, the thin margin of which descends a short distance between the thoracic wall
and the solid mass of the liver.

The right surface is protected by the seventh to the llth ribs, and the anterior
surface by the fifth, sixth, seventh, eighth, and ninth costal cartilages, with the



126 ORGANS OF DIGESTION.

anterior parts of the corresponding ribs, and by the ensiform cartilage, the
diaphragm, of course, being interposed. The upper limit of the liver may be
indicated on the anterior wall of the chest by a line which crosses the median plane
at the lower end of the body of the sternum. On the right side this line must be
extended outwards and slightly upwards, so that in the mammary line it is near the
upper edge of the fifth rib, from which point- it descends towards the seventh rib in
the mid-axillary line. On the left side the line passes nearly horizontally outwards,
being slightly overlapped by the heart.

Its lower limit on the right side practically coincides with the lower edge of the
thoracic wall as far inwards as the tip of the ninth costal cartilage. About this
point the line representing its lower edge passes upwards and to the left, to near the
tip of the eighth costal cartilage. It is then continued in the same direction
across the left costal cartilages, to meet the left end of the upper limit at an acute
angle.

The situation of the liver is modified by the position of the body, and also by the
movements of respiration. Thus, in the upright or sitting position it descends
to just below the lateral margin of the thorax, but in the recumbent posture ascends
half an inch or an inch higher up, and is entirely covered by the ribs, except
a small portion opposite the sub-costal angle. During a deep inspiration the liver

Fig. 149. SKETCH OP A PORTION OF THE UNDER SUR-
FACE OF THE LIVER, SHOWING THE ARRANGEMENT
OF THE VESSELS IN THE PORTAL FISSURE. (Gr. D. T. )

a, hepatic artery ; p, portal vein ; d, bile-duct ;
g.bl, gall-bladder; p' A , p*, lines of reflection of the
peritoneum.

also descends below the ribs, even in the
recumbent posture, and in expiration
retires up behind them. In females it is
often permanently forced downwards below
the costal cartilages, owing to the use of tight
stays ; sometimes it reaches nearly as low as

the crest of the ilium, and in many such cases its convex surface is indented from
the pressure of the ribs.

The position of the liver is also affected by the condition of its neighbouring
organs. Thus, when the intestines are distended and the abdomen prominent, the
liver is pushed upwards, and its vertical extent diminished, while when these are
empty and the abdominal wall retracted, the liver is compressed from before
backwards, and the inferior surface is nearly in the same plane as the posterior.
Again, with the distension of the stomach the left lobe of the liver is pushed over
towards the right side.

Vessels and Nerves. The two vessels by which the liver is supplied with
blood are the hepatic artery and the portal vein. The hepatic artery (fig. 149),
a branch of the coaliac axis, is small in comparison with the organ to which it is
distributed. It enters the transverse fissure, and there divides into a right and left
branch for the two principal lobes.

By far the greater part of the blood which passes through the liver and in this
respect it differs from all other organs of the human body is conveyed to it by a
large vein, the portal vein, or vena portae (fig. 149). This vein is formed by the
union of the veins of the stomach, intestines, pancreas, and spleen. It enters the
transverse fissure, or porta hepatis, and, like the hepatic artery, there divides into
two principal branches.

The hepatic artery and portal vein, lying in company with the bile-duct, ascend




THE LIVER. 127

to the liver between the layers of the gastro-hepatic omentum, in front of the
foramen of Winslow, and thus reach the transverse fissure. In this course the
bile-duct is to the right, the hepatic artery to the left, and the large portal vein
behind the other two. They are accompanied by numerous lymphatic vessels and
nerves. The branches of the three vessels accompany one another in their course
through the liver nearly to their termination, and are surrounded for some distance
by an arcolar investment, the so-called capsule of Glisson, which is prolonged into
the interior of the organ.

The hepatic veins, which convey the blood away from the liver, pursue through
its substance an entirely different course from the other vessels, and pass out at its
posterior surface, where, at the upper part of the fossa already described, they end
by two or three principal branches, besides a number of smaller ones, in the vena
cava inferior.

The lymphatics of the liver, large and numerous, form a deep and a superficial
set. Their mode of origin and their course will be afterwards described.

The nerves are derived partly from the coeliac plexus, and partly from the
pneumogastric nerves, especially from the left pneumogastric. They enter the liver
supported by the hepatic artery and its branches, along with which they may be
traced in the portal canals.

EXCRETORY APPARATUS. The excretory apparatus of the liver consists of the
hepatic dud, the cystic duct, the gall-bladder, and the common bile-duct.

The hepatic duct, formed by the union of a right and left branch, which
issue from the bottom of the transverse fissure and unite at a very obtuse angle,
descends to the right, within the gastro-hepatic omentum, in front of the vena
portse, and with the hepatic artery to its left. Its diameter is about |th of an inch
(4 mm.), and its length nearly two inches (one inch only, according to Luschka)
At its lower end it meets with the cystic duct, descending from the gall-
bladder, and the two ducts uniting together at an acute angle form the common
bile-duct.

The gall-bladder (fig. 147, g.U.}, is a pear-shaped membranous sac, 3 or 4
inches (75 to 100 mm.) long, about an inch and a half (35 mm.) across its widest
part, and capable of containing from 8 to 12 fluid-drachms (30 to 50 cub. cent.).
It is lodged obliquely in the fossa before mentioned on the under surface of the
right lobe, with its large end or fundus, which projects beyond the anterior border
of the liver, directed forwards, downwards, and to the right, whilst its neck is
inclined in the opposite direction. Its upper surface is attached to the liver by
areolar tissue. Its under surface and fundus are covered by the peritoneum,
which is reflected over them from the surface of the liver. In rare cases the
peritoneum completely surrounds the gall-bladder, which is then suspended by
a sort of mesentery from the under surface of the liver. The fundus generally
touches the abdominal parietes immediately beneath the margin of the thorax,
opposite the ninth costal cartilage. It is, however, subject to considerable varia-
tions. Thus, if the liver be small, or the gall-bladder empty, it often fails
to reach the abdominal wall. In cases of distension of the stomach it may be
displaced to the right. The gall-bladder rests below on the commencement of the
transverse colon ; and, farther back, it is in contact with the duodenum, and some-
times with the pyloric extremity of the stomach. The neck, gradually narrowing, is
curved like the letter S, and then, becoming much constricted, and changing its
general direction altogether, it bends downwards and terminates in the cystic duct.

The gall-bladder is supplied with blood by the cystic artery, a branch of the
right division of the hepatic artery, along which vessel it also receives nerves from
the cceliac plexus. The cystic veins empty themselves into the vena port*.



128 ORGANS OF DIGESTION.

The cystic duct is about an inch and a half in length (35 mm., Luschka),
and only about T Yth of an inch wide (2'3 mm., Krause). It runs backwards,
downwards, and to the left, and unites with the hepatic duct to form the common
bile-duct.

The common bile-duct, ductus communis choledochus, about % of an inch
(tV6 mm. to 7'f> mm., Krause) in width, and nearly three inches (about 70 mm.)
in length, conveys the bile into the duodenum. It passes downwards and back-
wards, continuing the course of the hepatic duct, between the layers of the gastro-
hepatic omentum, in front of the vena portae, and to the right of the hepatic artery,
Passing behind the first part of the duodenum it reaches the descending portion
and continues downwards on the inner and posterior aspect of that part of the
intestine, covered by or included in the head of the pancreas, and for a short
distance in contact with the right side of the pancreatic duct. Together with that
duct, it then perforates the muscular wall of the duodenum, and, after running
obliquely for three quarters of an inch between its coats, and forming an elevation
beneath the mucous membrane, it becomes somewhat constricted, and opens by a
common orifice with the pancreatic duct on the inner surface of the intestine,
near the junction of the second and third portions of the duodenum, and three or
four inches beyond the pylorus, as already described.

Liver in the Infant. The liver is relatively much larger in the new-born
child than in the adult. Indeed, at birth, it occupies nearly one half of the
abdominal cavity. The left lobe, as compared with the right, is distinctly larger
than in the adult, and often reaches to the left, so as to come in contact with
the lateral wall of the abdomen on that side, presenting in this position a distinct
left surface. In such cases Ballantyne describes the anterior surface as being
more nearly quadrilateral than triangular. According to this authority, the
anterior surface of the liver in the new-born infant corresponds in its vertical extent
in the median plane with the last four dorsal and upper two lumbar vertebrae, and its
lower border is within 2 cm. of the umbilicus. Its vertical extent increases from
left to right, the lower edge of the right surface coming within 1 cm. or l-f> cm. of
the right iliac crest.

Varieties. The liver is not subject to great or frequent deviation from its ordinary
form and relations. It has been found without any division into lobes. On the other hand,
Soemmerring has recorded a case in which the adult liver was divided into twelve lobes, and
similar cases of subdivided liver (resembling that of some animals) have been now and then
observed by others. A detached portion, forming a sort of accessory liver, is occasionally
found appended to the left extremity of the gland by a fold of peritoneum containing blood-
vessels. The upper surface sometimes shows longitudinal furrows, which are occupied, when
the organ is in situ, by folds of the diaphragm. These have been attributed to tight lacing,
but, according to Turner, they are found almost as frequently in males as in females, and
are probably congenital. Various cases have been described of unusual mobility of the liver
in women with flaccid and often pendulous abdominal walls (see Landau, Die Wanderleber
tmd der Hiinfjebaiirh der Frtnte-n, 1888).

The gall-bladder is occasionally wanting, in which case the hepatic duct is much dilated
within the liver, or in some part of its course. Sometimes the gall-bladder is irregular in
form, or is constricted across its middle, or, but much more rarely, it is partially divided in
a longitudinal direction. Purser (Trans. Acad. Med., Ireland, Vol. V.) has recorded a case in
which there were two distinct gall-bladders, each having a cystic duct which joined the
hepatic duct. The gall-bladder has been found on the left side (Hochstetter, Arch. f. Anat..
1886) in subjects in which there was no general transposition of the thoracic and abdominal
viscera. Direct communications by means of small ducts (named hepato-cystic), passing
from the liver to the gall-bladder, exist regularly in various animals ; and they are sometimes
found, as an unusual formation, in the human subject.

The right and left divisions of the hepatic duct sometimes continue separate for some
distance within the gastro-hepatic omentum. Lastly, the common bile-duct not unfrequently
opens separately from the pancreatic duct into the duodenum.



THE LIVER. 129



STRUCTURE OF THE LIVER.

The liver is covered externally by a serous coat derived from the peritoneum.
This, with its folds and so-called ligaments, has already received notice. In its
general structure it resembles other serous membranes, but no stomata have as yet
been described in it. Connecting the serous coat to the glandular substance, aud
also present where the serous coat is absent, is a layer of areolar tissue, which
is described as the areolar or fibrous coat of the organ. Its inner surface is
connected with the delicate areolar tissue which lies between the hepatic lobules.
Opposite the transverse fissure, where it is greatly increased in amount, it invests
the entering and issuing vessels and duct, forming for them a loose but strong-
sheath of areolar tissue, which surrounds all their branches as they ramify through
the organ, becoming more and more delicate, until it becomes continuous with the
areolnr tissue between the lobules. To this investment of areolar tissue, which
encloses the three vessels above mentioned, and their branches, the name capsule of
Glisson has been applied, and the canals through the liver substance which are
occupied by those vessels and their " capsule " have been termed portal canals.
At the back of the liver, where there is no serous coat, the areolar coat is also

Fig. 150. SECTION OF A PORTAL CANAL (E. A. S.).
Magnified.

a, branch of hepatic artery ; v, branch of portal vein ;
d, bile-duct ; /, I, lymphatics in the areolar tissue of Glisson's
capsule which encloses the vessels.

considerably thickened, and it here invests the
hepatic veins as they issue from the organ to
open into the vena cava inferior. These veins
and their tributaries are also invested in their
course through the liver by areolar tissue con-
tinuous with that of the areolar coat, but it is
very small in amount, and binds the hepatic
veins closely to the glandular substance, so that
in section of these hepatic canals in the dead
liver the vein always remains patent, whereas in
section of the portal canals the looseness of the

areolar tissue investing them, and the large relative amount of this tissue, enables
the branches of the portal vein to collapse, and this is their usual condition when
seen in section, if empty of blood. Both the portal and the hepatic canals conduct
lymphatic vessels, which discharge their lymph into lymphatic glands, situated
respectively at the transverse fissure and behind the organ.

Hepatic lobules. The proper substance of the liver, which has a mottled
aspect when closely observed, is compact, but not very firm. It, is easily cut
or lacerated, aud is not unfrequently ruptured during life from accidents in which
other parts of the body have escaped injury. When the substance of the liver is
torn, the broken surface is not smooth, but coarsely granular, the liver being
composed of a multitude of small lobules (fig. 151), which vary from -jVth to ^fh of
an inch in diameter (1 2 millimeters).

These lobules in some animals, as in the pig and camel, are completely isolated
one from another by areolar tissue continuous with the fibrous coat of the liver, and
with the capsule of Glisson ; but in the human subject and in most animals,
although very distinguishable, they are confluent in a part of their extent.

The lobules of the liver have, throughout its substance, in general the polyhedral
form of irregularly compressed spheroids, but on the surface they are flattened and

VOL. III. PT. 4. K




130



ORGANS OF DIGESTION.



angular. They are all compactly arranged around the sides of branches (siiblolular)
of the hepatic veins (fig. 151), each lobule resting, by a smooth surface or base, upon
the vein, and being connected with it by a small venous trunklet (intralobular),
which begins in the centre of the lobule, and passes out from the middle of its base,
to end in the larger subjacent vessel. If one of the sublobular veins be opened (as
in the figure), the bases of the lobules may be seen through the coats of the vein,
which are here very thin, presenting a tesselated appearance, each little polygonal
space representing the base of a lobule, and having in its centre a small spot, which
is the mouth of the mtralobular vein (').

Each lobule consists of a mass of cells penetrated from the circumference to the





Fig. 151. SECTION OF A PORTION OF LIVER PASSING LONGITUDINALLY THROUGH A CONSIDERABLE HEPATIC
VEIN, FROM THE PIG (after Kiernan). ABOUT 5 DIAMETERS.

H, hepatic venous trunk, against which the sides of the lobules are applied ; h, h, h, three
sublobular hepatic veins, on which the bases of the lobules rest, and through the coats of which they
are seen as polygonal figures ; i, mouth of the intralobular veins, opening into the sublobular veins ;.
i', intralobular veins shown passing up the centre of some divided lobules ; c, c, walls of the hepatic
venous canal, with the polygonal bases of the lobules.

Fig. 152. LONGITUDINAL SECTION OF A PORTAL CANAL, CONTAINING A PORTAL VEIN, HEPATIC ARTERY, AND-
HEPATIC DUCT, FROM THE PIG (after Kieruan). ABOUT 5 DIAMETERS.

p, branch* of vena portag, situated in a portal canal, formed amongst the lobules of the liver ;
p, p, larger branches of portal vein, giving off smaller ones named interlobular veins ; there are also-
seen within the large portal vein numerous orifices of interlobular veins arising directly from it ;
a, hepatic artery ; d, biliary duct ; at c, c, the venous wall has been partially removed.

centre by a close network of blood-capillaries, as well as by the minute capillary
commencements of the bile-ducts, with the intervention of little other tissue. For
convenience of description, the disposition of the vessels of the liver may be con-
sidered first.

Blood-vessels. The portal vein and hepatic artery, accompanied by the
emerging biliary ducts, enter the liver at the transverse fissure. Within the liver
the branches of these three vessels lie together in the portal canals.

The portal vein subdivides into branches which ramify between the lobules,
anastomosing freely around them, and are named interlobular or peripheral veins:
(fig. 153,j9). The branches of these pass into the lobules at their circumference,.



THE LIVER.



and end in the capillary network, from which the intralobular or central veins take
origin. Within the portal canals the branches of the portal vein jcecejve small
veins which are returning blood distributed by branches of the hepatic artery.

The hepatic artery terminates in three sets of branches, termed vaginal,
capsular, and interlobular. The vaginal branches ramify within the portal canals,




Fig. 153. DIAGRAMMATIC REPRESENTATION OF TWO HEPATIC LOBULES (E. A. S. )

The left-hand lobule is represented with the intralobular vein cut across ; in the right-hand one the
section takes ihe course of the intralobular vein, p, interlobular branches of the portal vein ; /*, intra-
lobular branches of the hepatic veins ; s, sublobular vein : c, capillaries of the lobules. The arrows
indicate the direction of the course of the blood. The liver-cells are only represented in one part
of each lobule.

supplying the walls of the ducts and vessels, and the accompanying connective

tissue. The capsular branches appear on the surface of the liver spread out on the

fibrous coat, accompanied by their veins. The interlobular branches accompany the

. incerlobular veins, but are much smaller ; they supply blood to the walls of these and

FIG. 154. CAPILLARY NETWORK OF
THE LOB0LES OF THE RABBIT'S
LIVKU (from Kolliker). ABOUT
40 DIAMETERS.

The figure is taken from a very



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