Abdominal aorta ppt

1. Abdominal aorta, its topography,
the parietal and visceral branches.
Blood supply of the organs of the
superior part of the abdominal
cavity. Portal vein, formation.

2. The questions for self-control
1. Blood supply of liver.
2. Blood supply of gall bladder.
3. Blood supply of stomach.
4. Blood supply of small intestine.
5. Blood supply of duodenum.
6. Blood supply of jejunum.
7. Blood supply of ileum.
8. Blood supply of large intestine.
9. Blood supply of ascending colon.
10. Blood supply of transverse colon
11. Blood supply of descending colon.
12. Blood supply of sigmoid colon.
13. Blood supply of rectum.
14. Blood supply of pancreas.
15. Blood supply of spleen.
16. Blood supply of kidneys. Structure of intraorganic
circulative system of kidneys.

3. Abdominal aorta
The abdominal aorta emerges from the aortic orifice of the
diaphragm at the level of T12 vertebra. It begins its course
anterior and to the left of the vertebral column and
continues downwards for about 10 cm.
Upon reaching the lower part of the body of L4 vertebra, it
bifurcates into its terminal branches to the left of the
median plane; the left and right common iliac arteries.
On the skin, this bifurcation is projected 1.5 cm below and
to the left of the umbilicus.

4. Relations.—The abdominal aorta is covered, anteriorly, by the lesser
omentum and stomach, behind which are the branches of the celiac artery
and the celiac plexus; below these, by the lienal vein, the pancreas, the left
renal vein, the inferior part of the duodenum, the mesentery, and aortic
plexus.
Posteriorly, it is separated from the lumbar vertebræ and intervertebral
fibrocartilages by the anterior longitudinal ligament and left lumbar veins.
On the right side it is in relation above with the azygos vein, cisterna chyli,
thoracic duct, and the right crus of the diaphragm—the last separating it
from the upper part of the inferior vena cava, and from the right celiac
ganglion; the inferior vena cava is in contact with the aorta below.
On the left side are the left crus of the diaphragm, the left celiac ganglion,
the ascending part of the duodenum, and some coils of the small intestine.
Collateral Circulation.—The collateral circulation would be carried on by
the anastomoses between the internal mammary and the inferior
epigastric; by the free communication between the superior and inferior
mesenterics, if the ligature were placed between these vessels; or by the
anastomosis between the inferior mesenteric and the internal pudendal,
when (as is more common) the point of ligature is below the origin of the
inferior mesenteric; and possibly by the anastomoses of the lumbar
arteries with the branches of the hypogastric.

5. Branches
Similarly to the branches of the thoracic aorta, the
branches of the abdominal aorta can be grouped as
visceral and parietal. However, a more commonly used
classification is based on where the branches arise off of
the aorta and are divided into anterior, lateral and dorsal
groups.
Anterior
group
Celiac trunk
Superior mesenteric artery
Inferior mesenteric artery
Lateral group Suprarenal artery
Renal artery
Gonadal artery
Dorsal group Inferior phrenic artery
Lumbar arteries
Median sacral arteries
Terminal
branches
Left common iliac artery
Right common iliac artery

6. The anterior group of branches involves the
celiac trunk, superior and inferior mesenteric
artery;
•Celiac trunk: an unpaired short vessel that arises on the
anterior aspect of the aorta just inferior to the aortic orifice
of the diaphragm at the level of the lower border of T12
vertebra. Shortly after its origin, the trunk gives off its
three branches; left gastric artery, common hepatic
artery and splenic artery. These arteries supply the
foregut, which is the part of the intestinal tract that lies
below the diaphragm up to the proximal duodenum. The
organs of the foregut that are supplied but the celiac
trunk include the abdominal part of the
esophagus, stomach,
proximal duodenum, liver, gallbladder, pancreas,
and spleen.

7. The Left Gastric Artery (a. gastrica sinistra;
gastric or coronary artery), the smallest of the three
branches of the celiac artery, passes upward and to
the left, posterior to the omental bursa, to the cardiac
orifice of the stomach. Here it distributes branches to
the esophagus, which anastomose with the aortic
esophageal arteries; others supply the cardiac part of
the stomach, anastomosing with branches of the
lienal artery. It then runs from left to right, along the
lesser curvature of the stomach to the pylorus,
between the layers of the lesser omentum; it gives
branches to both surfaces of the stomach and
anastomoses with the right gastric artery.
The Hepatic Artery (a. hepatica) in the adult is
intermediate in size between the left gastric and lienal; in the
fetus, it is the largest of the three branches of the celiac artery. It
is first directed forward and to the right, to the upper margin of
the superior part of the duodenum, forming the lower boundary
of the epiploic foramen (foramen of Winslow). It then crosses the
portal vein anteriorly and ascends between the layers of the
lesser omentum, and in front of the epiploic foramen, to the
porta hepatis, where it divides into two branches, right and left,
which supply the corresponding lobes of the liver, accompanying
the ramifications of the portal vein and hepatic ducts. The hepatic
artery, in its course along the right border of the lesser
omentum, is in relation with the common bile-duct and portal
vein, the duct lying to the right of the artery, and the vein
behind.
Its branches are:
Right Gastric.
Gastroduodenal
Right Gastroepiploic.
Superior Pancreaticoduodenal.
Cystic.
The celiac artery and its branches; the liver has been raised, and the lesser omentum
and anterior layer of the greater omentum removed.

8. The gastroduodenal artery (a. gastroduodenalis) is a short but large branch, which descends,
near the pylorus, between the superior part of the duodenum and the neck of the pancreas, and divides
at the lower border of the duodenum into two branches, the right gastroepiploic and the superior
pancreaticoduodenal. Previous to its division it gives off two or three small branches to the pyloric
end of the stomach and to the pancreas.
The right gastroepiploic artery (a. gastroepiploica dextra) runs from right to left along the greater
curvature of the stomach, between the layers of the greater omentum, anastomosing with the left
gastroepiploic branch of the lienal artery. Except at the pylorus where it is in contact with the stomach,
it lies about a finger's breadth from the greater curvature. This vessel gives off numerous branches,
some of which ascend to supply both surfaces of the stomach, while others descend to supply the
greater omentum and anastomose with branches of the middle colic.
The superior pancreaticoduodenal artery (a. pancreaticoduodenalis superior) descends
between the contiguous margins of the duodenum and pancreas. It supplies both these organs, and
anastomoses with the inferior pancreaticoduodenal branch of the superior mesenteric artery, and with
the pancreatic branches of the lienal artery.
The celiac artery and its branches; the stomach has been raised and the peritoneum removed.
The cystic artery (a. cystica) usually a branch of the right hepatic, passes downward and forward
along the neck of the gall-bladder, and divides into two branches, one of which ramifies on the free
surface, the other on the attached surface of the gall-bladder.

9. 3. The Lienal or Splenic Artery (a. lienalis), the largest
branch of the celiac artery, is remarkable for the tortuosity
of its course. It passes horizontally to the left side, behind
the stomach and the omental bursa of the peritoneum,
and along the upper border of the pancreas, accompanied
by the lienal vein, which lies below it; it crosses in front of
the upper part of the left kidney, and, on arriving near the
spleen, divides into branches, some of which enter the
hilus of that organ between the two layers of the
phrenicolienal ligament to be distributed to the tissues of
the spleen; some are given to the pancreas, while others
pass to the greater curvature of the stomach between the
layers of the gastrolienal ligament. Its branches are:
Pancreatic.
Short Gastric.
Left Gastroepiploic.

10. The pancreatic branches (rami pancreatici) are numerous small vessels derived from the lienal as it runs behind
the upper border of the pancreas, supplying its body and tail. One of these, larger than the rest, is sometimes
given off near the tail of the pancreas; it runs from left to right near the posterior surface of the gland, following
the course of the pancreatic duct, and is called the arteria pancreatica magna. These vessels anastomose with
the pancreatic branches of the pancreaticoduodenal and superior mesenteric arteries.

11. •Superior mesenteric artery: an unpaired artery that arises
about 1 cm below the celiac trunk, at the level of L1
vertebra. It supplies blood to the midgut, which refers to
the parts of the intestinal tract lying between the proximal
segment of the duodenum and the distal 1/3 of
the transverse colon of the large intestine. It, therefore,
supplies most of the small intestine, cecum and appendix,
ascending colon and the first 2/3 of the transverse colon.
•Inferior mesenteric artery: an unpaired artery that arises
about 4 cm superior to the bifurcation of the abdominal
aorta, at the level of L3 vertebra. It supplies blood to the
hindgut, which refers to the remaining segments of the
intestinal tract that include the distal 1/3 of the transverse
colon, descending colon, sigmoid colon, rectum, and the
superior portion of the anal canal.

12. The superior mesenteric artery and its branches.
The short gastric arteries (aa. gastricæ breves; vasa brevia)
consist of from five to seven small branches, which arise from the end of the lienal
artery, and from its terminal divisions. They pass from left to right, between the layers
of the gastrolienal ligament, and are distributed to the greater curvature of the stomach,
anastomosing with branches of the left gastric and left gastroepiploic arteries.
The left gastroepiploic artery (a. gastroepiploica sinistra) the largest
branch of the lienal, runs from left to right about a finger’s breadth or more from the
greater curvature of the stomach, between the layers of the greater omentum, and
anastomoses with the right gastroepiploic. In its course it distributes several ascending
branches to both surfaces of the stomach; others descend to supply the greater
omentum and anastomose with branches of the middle colic.
The superior mesenteric artery (a. mesenterica superior) is a large vessel
which supplies the whole length of the small intestine, except the superior part of the
duodenum; it also supplies the cecum and the ascending part of the colon and about
one-half of the transverse part of the colon. It arises from the front of the aorta, about
1.25 cm. below the celiac artery, and is crossed at its origin by the lienal vein and the
neck of the pancreas. It passes downward and forward, anterior to the processus
uncinatus of the head of the pancreas and inferior part of the duodenum, and descends
between the layers of the mesentery to the right iliac fossa, where, considerably
diminished in size, it anastomoses with one of its own branches, viz., the ileocolic. In
its course it crosses in front of the inferior vena cava, the right ureter and Psoas major,
and forms an arch, the convexity of which is directed foward and downward to the left
side, the concavity backward and upward to the right. It is accompanied by the superior
mesenteric vein, which lies to its right side, and it is surrounded by the superior
mesenteric plexus of nerves.

13. The Inferior Pancreaticoduodenal Artery (a. pancreaticoduodenalis inferior) is given off from the
superior mesenteric or from its first intestinal branch, opposite the upper border of the inferior part of
the duodenum. It courses to the right between the head of the pancreas and duodenum, and then
ascends to anastomose with the superior pancreaticoduodenal artery. It distributes branches to the
head of the pancreas and to the descending and inferior parts of the duodenum.
The Intestinal Arteries (aa. intestinales; vasa intestini tenuis) arise from the convex side of the
superior mesenteric artery. They are usually from twelve to fifteen in number, and are distributed to
the jejunum and ileum. They run nearly parallel with one another between the layers of the mesentery,
each vessel dividing into two branches, which unite with adjacent branches, forming a series of
arches, the convexities of which are directed toward the intestine. From this first set of arches
branches arise, which unite with similar branches from above and below and thus a second series of
arches is formed; from the lower branches of the artery, a third, a fourth, or even a fifth series of
arches may be formed, diminishing in size the nearer they approach the intestine. In the short, upper
part of the mesentery only one set of arches exists, but as the depth of the mesentery increases,
second, third, fourth, or even fifth groups are developed. From the terminal arches numerous small
straight vessels arise which encircle the intestine, upon which they are distributed, ramifying between
its coats. From the intestinal arteries small branches are given off to the lymph glands and other
structures between the layers of the mesentery.

14. The Ileocolic Artery (a. ileocolica) is the lowest branch arising from the concavity of the superior
mesenteric artery. It passes downward and to the right behind the peritoneum toward the right iliac fossa,
where it divides into a superior and an inferior branch; the inferior anastomoses with the end of the superior
mesenteric artery, the superior with the right colic artery.
The inferior branch of the ileocolic runs toward the upper border of the ileocolic junction and
supplies the following branches:
(a) colic, which pass upward on the ascending colon; (b) anterior and posterior cecal, which are distributed
to the front and back of the cecum; (c) an appendicular artery, which descends behind the termination of the
ileum and enters the mesenteriole of the vermiform process; it runs near the free margin of this mesenteriole
and ends in branches which supply the vermiform process; and (d) ileal, which run upward and to the left on
the lower part of the ileum, and anastomose with the termination of the superior mesenteric.
Loop of small intestine showing distribution of intestinal arteries. (From a preparation by Mr. Hamilton
Drummond.) The vessels were injected while the gut was in situ; the gut was then removed, and an x-ray
photograph taken.
The Middle Colic Artery (a. colica media) arises from the superior mesenteric just below the pancreas
and, passing downward and forward between the layers of the transverse mesocolon, divides into two
branches, right and left; the former anastomoses with the right colic; the latter with the left colic, a branch of
the inferior mesenteric. The arches thus formed are placed about two fingers’ breadth from the transverse
colon, to which they distribute branches.

15. The inferior mesenteric artery (a. mesenterica
inferior)
supplies the left half of the transverse part of the colon,
the whole of the descending and iliac parts of the colon,
the sigmoid colon, and the greater part of the rectum. It is
smaller than the superior mesenteric, and arises from the
aorta, about 3 or 4 cm. above its division into the common
iliacs and close to the lower border of the inferior part of
the duodenum. It passes downward posterior to the
peritoneum, lying at first anterior to and then on the left
side of the aorta. It crosses the left common iliac artery
and is continued into the lesser pelvis under the name of
the superior hemorrhoidal artery, which descends
between the two layers of the sigmoid mesocolon and
ends on the upper part of the rectum.
Branches.—Its branches are:
Left Colic.
Sigmoid.
Superior Hemorrhoidal.

16. The Left Colic Artery (a. colica sinistra) runs to the left behind the peritoneum and in front of the Psoas
major, and after a short, but variable, course divides into an ascending and a descending branch; the stem of
the artery or its branches cross the left ureter and left internal spermatic vessels. The ascending branch
crosses in front of the left kidney and ends, between the two layers of the transverse mesocolon, by
anastomosing with the middle colic artery; the descending branch anastomoses with the highest sigmoid artery.
From the arches formed by these anastomoses branches are distributed to the descending colon and the left
part of the transverse colon.
The Sigmoid Arteries (aa. sigmoideæ), two or three in number, run obliquely downward and to the left
behind the peritoneum and in front of the Psoas major, ureter, and internal spermatic vessels. Their branches
supply the lower part of the descending colon, the iliac colon, and the sigmoid or pelvic colon; anastomosing
above with the left colic, and below with the superior hemorrhoidal artery.
The Superior Hemorrhoidal Artery (a. hæmorrhoidalis superior, the continuation of the inferior
mesenteric, descends into the pelvis between the layers of the mesentery of the sigmoid colon, crossing, in its
course, the left common iliac vessels. It divides, opposite the third sacral vertebra, into two branches, which
descend one on either side of the rectum, and about 10 or 12 cm. from the anus break up into several small
branches. These pierce the muscular coat of the bowel and run downward, as straight vessels, placed at
regular intervals from each other in the wall of the gut between its muscular and mucous coats, to the level of
the Sphincter ani internus; here they form a series of loops around the lower end of the rectum, and
communicate with the middle hemorrhoidal branches of the hypogastric, and with the inferior hemorrhoidal
branches of the internal pudendal.

17. The lateral group of branches of the abdominal aorta
involves the suprarenal, renal and gonadal arteries:
•Middle suprarenal artery: a paired artery that arises on
each lateral side of the abdominal aorta near the origin of the
superior mesenteric artery. Along with the superior and inferior
suprarenal arteries, these arteries supply blood to
the suprarenal glands.
•Renal artery: a large paired artery that branches off the
lateral sides of the aorta at a right angle immediately below
the superior mesenteric artery. It supplies blood to the left and
right kidney and gives off the inferior suprarenal artery to
supply the suprarenal glands.
•Gonadal artery: a paired artery that arises from the anterior
aspect of the aorta just inferior to the renal arteries. In males,
this artery is called the testicular artery and supplies
the testes, while the female counterpart is called the ovarian
artery, which supplies the ovaries.

18. The internal spermatic arteries (aa. spermaticæ
internæ; spermatic arteries) are distributed to
the testes. They are two slender vessels of considerable
length, and arise from the front of the aorta a little below
the renal arteries. Each passes obliquely downward and
lateralward behind the peritoneum, resting on the Psoas
major, the right spermatic lying in front of the inferior vena
cava and behind the middle colic and ileocolic arteries and
the terminal part of the ileum, the left behind the left colic
and sigmoid arteries and the iliac colon. Each crosses
obliquely over the ureter and the lower part of the external
iliac artery to reach the abdominal inguinal ring, through
which it passes, and accompanies the other constituents
of the spermatic cord along the inguinal canal to the
scrotum, where it becomes tortuous, and divides into
several branches. Two or three of these accompany the
ductus deferens, and supply the epididymis,
anastomosing with the artery of the ductus deferens;
others pierce the back part of the tunica albuginea, and
supply the substance of the testis. The internal spermatic
artery supplies one or two small branches to the ureter,
and in the inguinal canal gives one or two twigs to the
Cremaster.

19. The dorsal group of branches includes the inferior
phrenic, lumbar, and median sacral arteries:
•Inferior phrenic artery: a paired artery that arises from
the posterolateral aspect of the aorta immediately below
the aortic hiatus of the diaphragm. This artery supplies the
inferior surface of the diaphragm and gives off the
superior suprarenal artery to supply the suprarenal
glands.
•Lumbar arteries: typically four pairs of arteries that arise
from the posterior surface of the aorta. They supply
the posterior abdominal wall and the spinal cord.
•Median sacral artery: arises from the posterior aspect of
the abdominal aorta just superior to the bifurcation. This
artery supplies blood to the lower lumbar vertebrae and
the sacrum.
The terminal branches of the abdominal aorta, the left and
right common iliac arteries, arise from the bifurcation in
front of the body of L4 vertebra about 1.25 cm to the left of
the median plane. The common iliac arteries supply
the lower limb, the gluteal region, and the pelvic viscera.

20. Lumbar arteries Median sacral artery

21. Aortic aneurysm
An aortic aneurysm is a localized enlargement of the aortic wall. It is most
commonly developed in the abdominal aorta, followed by the ascending aorta and
aortic arch. An aortic aneurysm is diagnosed when the increase in aortic wall
diameter is 1.5 times more than its normal size. Since the normal diameter of the
ascending aorta amounts to about 3.5 cm, and 2.5 cm for the abdominal aorta, the
diagnostic criteria for an aneurysm include a diameter of >5cm for the ascending
aorta, and >4cm for the abdominal aorta.
The abdominal aorta is the most commonly affected segment of the aorta due to
the fact that it contains less elastin in its wall compared to the ascending aorta, as
well as the fact that it lacks vasa vasorum, making it susceptible to degenerative
changes. The most common cause of an abdominal aorta is atherosclerosis, while
aneurysms in the ascending aorta and aortic arch commonly occur secondary
to connective tissue disorders such as Marfan’s syndrome and Ehlers–Danlos
syndrome.
An aortic aneurysm is often asymptomatic, only sometimes causing signs and
symptoms that are mostly the result of the aneurysm affecting nearby structures. An
aneurysm in the ascending aorta or aortic arch may cause shortness of breath and
cough due to compression of the lungs; or voice hoarseness due to stretching of
the recurrent laryngeal nerve. Likewise, an aneurysm of the abdominal aorta may
compress the spinal nerve roots and cause numbness in the lower extremities.

22. Hepatic portal vein
The hepatic portal vein is one of the most important vein that receives
blood from the body and transports it into the liver for filtration and
processing. This vein is part of the hepatic portal system that receives
all of the blood draining from the abdominal digestive tract, as well as
from the pancreas, gallbladder, and spleen.
Tributaries Main: superior mesenteric vein and splenic
vein
Additional: posterior superior
pancreaticoduodenal vein, left and right
gastric veins
Drains blood from: stomach, intestines,
pancreas and spleen
Course superior mesenteric + splenic -> portal vein -
> enters the liver -> divides into portal
venules -> venules empty into hepatic
sinusoids -> sinusoids drain into central
veins -> central veins drain into hepatic veins
-> hepatic veins drain into inferior vena cava
Function Claims available nutrients absorbed in the
gastrointestinal tract (GIT); transports toxins
from GIT to the liver
Clinical
relation
Portal hypertension

23. Location
Generally, the hepatic portal vein is about 8 centimeters (3
inches) long in adults, and is located in the upper right
quadrant of the abdomen, which originates behind the
neck of the pancreas and is part of the hepatic portal
system.
Formation
While there may be some variations between individuals,
the hepatic portal vein is usually formed by the
convergence of the superior mesenteric vein and
the splenic vein, referred to as the splenic-mesenteric
confluence.
In some individuals, the hepatic portal vein also directly
joins with the inferior mesenteric vein. Even less common,
but also possible anastomoses are the cystic and gastric
veins.
Course
The liver receives blood from two sources: the hepatic portal vein (70%),
and the hepatic arteries (30%). The hepatic portal vein receives blood
specifically from the stomach, intestines, pancreas, and spleen, and carries
it into the liver through the porta hepatis. The porta hepatis serves as the
point of entry for the hepatic portal vein and the proper hepatic artery, and
is the point of exit for the bile passages.

24. The portal vein (vena portæ) is about 8 cm. in length, and is formed at the level of the second lumbar vertebra
by the junction of the superior mesenteric and lienal veins, the union of these veins taking place in front of the inferior vena cava
and behind the neck of the pancreas. It passes upward behind the superior part of the duodenum and then ascends in the right
border of the lesser omentum to the right extremity of the porta hepatis, where it divides into a right and a left branch, which
accompany the corresponding branches of the hepatic artery into the substance of the liver. In the lesser omentum it is placed
behind and between the common bile duct and the hepatic artery, the former lying to the right of the latter. It is surrounded by
the hepatic plexus of nerves, and is accompanied by numerous lymphatic vessels and some lymph glands.
The right branch of the portal vein enters the right lobe of the liver, but before doing so generally receives the cystic vein.
The left branch, longer but of smaller caliber than the right, crosses the left sagittal fossa, gives branches to the caudate
lobe, and then enters the left lobe of the liver. As it crosses the left sagittal fossa it is joined in front by a fibrous cord,
the ligamentum teres (obliterated umbilical vein), and is united to the inferior vena cava by a second fibrous cord,
the ligamentum venosum (obliterated ductus venosus).

25. The Lienal Vein (v. lienalis; splenic
vein) commences by five or six large branches which return
the blood from the spleen. These unite to form a single vessel,
which passes from left to right, grooving the upper and back part of the
pancreas, below the lineal artery, and ends behind the neck of the
pancreas by uniting at a right angle with the superior mesenteric to
form the portal vein. The lienal vein is of large size, but is not tortuous
like the artery.
Tributaries.—The lineal vein receives the short gastric veins, the
left gastroepiploic vein, the pancreatic veins, and the inferior
mesenteric veins.
The short gastric veins (vv. gastricæ breves), four or five in
number, drain the fundus and left part of the greater curvature of the
stomach, and pass between the two layers of the gastrolienal ligament
to end in the lienal vein or in one of its large tributaries.
The left gastroepiploic vein (v. gastroepiploica sinistra)
receives branches from the antero-superior and postero-inferior
surfaces of the stomach and from the greater omentum; it runs from
right to left along the greater curvature of the stomach and ends in the
commencement of the lienal vein.
The pancreatic veins (vv. pancreaticæ) consist of several small
vessels which drain the body and tail of the pancreas, and open into
the trunk of the lienal vein.

26. The inferior mesenteric vein
(v. mesenterica inferior) returns blood from
the rectum and the sigmoid, and descending parts
of the colon. It begins in the rectum as
the superior hemorrhoidal vein, which has its
origin in the hemorrhoidal plexus, and through this
plexus communicates with the middle and inferior
hemorrhoidal veins. The superior hemorrhoidal
vein leaves the lesser pelvis and crosses the left
common iliac vessels with the superior
hemorrhoidal artery, and is continued upward as
the inferior mesenteric vein. This vein lies to the
left of its artery, and ascends behind the
peritoneum and in front of the left Psoas major; it
then passes behind the body of the pancreas and
opens into the lienal vein; sometimes it ends in
the angle of union of the lienal and superior
mesenteric veins.
Tributaries.—The inferior mesenteric vein
receives the sigmoid veins from the sigmoid
colon and iliac colon, and the left colic vein from
the descending colon and left colic flexure.

27. The Superior Mesenteric Vein (v.
mesenterica superior) returns the blood
from the small intestine, from the cecum,
and from the ascending and transverse
portions of the colon. It begins in the right
iliac fossa by the union of the veins which
drain the terminal part of the ileum, the
cecum, and vermiform process, and ascends
between the two layers of the mesentery on
the right side of the superior mesenteric
artery. In its upward course it passes in front
of the right ureter, the inferior vena cava,
the inferior part of the duodenum, and the
lower portion of the head of the pancreas.
Behind the neck of the pancreas it unites
with the lienal vein to form the portal vein.

28. Tributaries.—Besides the tributaries which correspond with
the branches of the superior mesenteric artery, viz., theintestinal,
ileocolic, right colic, and middle colic veins, the superior mesenteric
vein is joined by the right gastroepiploic and pancreaticoduodenal
veins.
The right gastroepiploic vein (v. gastroepiploica dextra)
receives branches from the greater omentum and from the lower parts
of the antero-superior and posteroinferior surfaces of the stomach; it
runs from left to right along the greater curvature of the stomach
between the two layers of the greater omentum.
The pancreaticoduodenal veins (vv. pancreaticoduodenales)
accompany their corresponding arteries; the lower of the two
frequently joins the right gastroepiploic vein.
The Coronary Vein (v. coronaria ventriculi; gastric vein)
derives tributaries from both surfaces of the stomach; it runs from
right to left along the lesser curvature of the stomach, between the two
layers of the lesser omentum, to the esophageal opening of the
stomach, where it receives some esophageal veins. It then turns
backward and passes from left to right behind the omental bursa and
ends in the portal vein.
The Pyloric Vein is of small size, and runs from left to right
along the pyloric portion of the lesser curvature of the stomach,
between the two layers of the lesser omentum, to end in the portal
vein.
The Cystic Vein (v. cystica) drains the blood from the gall-
bladder, and, accompanying the cystic duct, usually ends in the right
branch of the portal vein.

29. Parumbilical Veins (vv. parumbilicales).—In the course of the
ligamentum teres of the liver and of the middle umbilical ligament, small
veins (parumbilical) are found which establish an anastomosis between
the veins of the anterior abdominal wall and the portal, hypogastric, and
iliac veins. The best marked of these small veins is one which
commences at the umbilicus and runs backward and upward in, or on
the surface of, the ligamentum teres between the layers of the falciform
ligament to end in the left portal vein.
Collateral venous circulation to relieve portal obstruction in the liver
may be effected by communications between (a) the gastric veins and
the esophageal veins which often project as a varicose bunch into the
stomach, emptying themselves into the hemiazygos vein; (b) the veins of
the colon and duodenum and the left renal vein; (c) the accessory portal
system of Sappey, branches of which pass in the round and falciform
ligaments (particularly the latter) to unite with the epigastric and internal
mammary veins, and through the diaphragmatic veins with the azygos; a
single large vein, shown to be a parumbilical vein, may pass from the
hilus of the liver by the round ligament to the umbilicus, producing there
a bunch of prominent varicose veins known as the caput medusæ; (d)
the veins of Retzius, which connect the intestinal veins with the inferior
vena cava and its retroperitoneal branches; (e) the inferior mesenteric
veins, and the hemorrhoidal veins that open into the hypogastrics; (f)
very rarely the ductus venosus remains patent, affording a direct
connection between the portal vein and the inferior vena cava.