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Omran Saeed

Mohammad Al-muhtaseb

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Posterior abdominal wall

- The diaphragm separates between thoracic cavity and abdominal

cavity.

Structures of posterior abdominal wall: (below diaphragm)

Psoas major

Muscles Psoas minor* (if present)

Quadratus lumborum

Iliacus

- Aponeurosis of transversus abdominis muscle.

- The five-lumber vertebra and their intervertebral discs.

- Iliac crest, iliac fossa.

rib). th(12 The last rib -

Nerve supply action insertion Origin

12 T

1L

2L

3L

Flexion of the thigh and vertebral column

Lesser trochanter of femur

Bodies, transverse prosses of lumbar vertebra and inter vertebral discs

Psoas major

Femoral nerve

Lateral flexion of hip & thigh

Lesser trochanter of femur

Iliac fossa Iliacus

12 T

1L

2L

3L

Fixation of the last rib or stretch the rib downward

Last rib Iliolumbar ligament** And iliac crest

Quadratus lumborum

* There are many muscles which are not present in all population such

as palmaris longus in the upper limb and pyramidalis muscle.

lumbar vertebrae th** It is located between iliac crest and 5

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the part ofwhich is ,(medial, median and lateral) ligamentrcuate A -

origin of diaphragm, arches above psoas and quadratus muscles.

Median is in the middle above abdominal aorta

Medial above psoas major.

Lateral above quadratus lumborum.

Refer to diaphragm slide in the MSS system for illustration.

Look at slide number 7 in our lecture. The doctor mentioned latissimus

dorsi muscle, lumbar fascia, digitation of external oblique muscle, Lateral

cutaneous nerve and subcostal nerves which come from the chest.

Structures in the posterior abdominal wall

We will focus on abdominal aorta and inferior vena cava.

Abdominal aorta

➢ starts as ascending aorta emerge from left ventricle of the heart

and give us the right and left coronary arteries of the heart. Then

it becomes the arch of the aorta. After that it continues as

descending thoracic then abdominal aorta which ends in the right

and left common iliac arteries. Common iliac branches to external

and internal iliac. The external drains to the lower limb while the

internal drains to the pelvic viscera (More details later on).

-Now let’s talk about abdominal aorta.

It starts with an orifice in the diaphragm called aortic orifice (at the level

of T12 midline).

What are the structures pass through this orifice?

• Azygous vein.

• cisterna chyli (lymphatic sac) at the right side of abdominal aorta.

Abdominal aorta ends at L4 lumbar vertebra and it is deviated to left

side.

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Relations of abdominal aorta:

Anterior:

Pancreas.

.of duodenum part) rd(3 Horizontal part

Coils of small intestines.

Crossed anteriorly by left renal vein (left renal vein drains to inferior

vena cava which is at the right side of abdominal aorta that’s why it

crosses abdominal aorta).

Right:

Inferior vena cava.

Cisterna chyli.

Beginning of azygous vein.

Left:

Sympathetic chain behind the edge of abdominal aorta.

*You can refer to the mind map in the last slide for more illustration.

Branches of abdominal aorta

Single branches: (3 front & I back)

anterior surface

1- celiac trunk:

-very short (about 1 cm).

origin: upper border of L1. Some books assume that the origin is from

the lower border of T12.

Branches:

- left gastric: Supplies the stomach and the lower third of esophagus.

- splenic: Tortuous, goes along the upper border of pancreas and gives

pancreatic arteries and ends in the hilum of spleen and gives 5 or 6

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branches. Also, it gives short gastric for the fundus of stomach 5 to 7

branches (present in gastrosplenic ligament).

- hepatic: drains to the liver and pass through the free edge of lesser

e ehind thwhich travels bartery gastroduodenalives us . It gomentum

first part of duodenum.

(gastroduodenal gives superior pancreaticoduodenal and right

gastroepiploic arteries).

It ends with right (gives cystic artery) and left hepatic arteries.

2- superior mesenteric artery:

Gives inferior pancreaticoduodenal, Right colic, middle colic and

ileocolic (the end of superior mesenteric gives anterior and posterior

cecal and the posterior gives appendicular then gives jejunal and iliac

branches as we said about them they are at the root of mesentery

and they make arcades and vasa recta. In the ilium it’s complicated

and short vasa recta).

3- interior mesenteric artery:

Origin: at the level of L3.

Horizontal part of duodenum is anterior to it (origin of the artery).

Branches:

-Left colic drains in the lateral third of transverse and descending

colon.

-Sigmoidal arteries drain in the sigmoid.

At the end of inferior mesenteric > superior rectal artery goes to the

rectal and upper half of anal canal.

***

* Remember that celiac supplies the foregut, superior mesenteric

d inferior mesenteric supplies hindgut supplies midgut an

posterior surface:

Median sacral artery. Some books consider that it is a continuation of

abdominal aorta.

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Marginal artery

anastomosis between colic arteries (arteries of ascending, transverse,

descending and sigmoid colon). So, there is an anastomosis between

these arteries.

It is located at the medial side of the colon and internal. (it makes

connection and wraps around the colon).

As we said the abdominal aorta branches to common iliac arteries (right

and left) then the common iliac gives internal and external iliac arteries.

The bifurcation of the common iliac artery on each side is crossed

anteriorly by the ureter.

external iliac artery: supplies the lower limb

Branches:

-Inferior epigastric artery. It Enters the rectus sheath and meets the

superior epigastric.

-Deep Circumflex iliac artery which goes to the anterior superior iliac

spine.

Internal iliac artery: supplies the pelvic viscera and lateral wall of the

pelvis (more details in urogenital system)

Branches:

1- Posterior division: goes parietal to the wall of pelvis

a- Iliolumbar artery ascends at the ala of the sacra and goes to the

lumber vertebra.

b- Lateral sacral arteries go to the sacrum and enter the foramina of

sacra. They start as two arteries then they become four (each

branch gives two branches).

c- Superior gluteal artery passes through the greater sciatic foramen

above piriformis.

2- Anterior division:

a- Obturator artery (occasionally from inferior epigastric artery) -

crosses obturator foramen and the pelvis.

b- Inferior gluteal artery passes through greater sciatic foramen

below piriformis muscle.

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c- Umbilical artery directed to the umbilicus and it gets obliterated

after delivery (obliteration for the distal part [becomes lateral

umbilical ligament]). The proximal part gives superior vesical

artery for the urinary bladder (superiorly to the bladder).

d- Uterine artery (females). It is tortious for the uterus or deferential

artery (males)

e- Vaginal artery (females, can also arise from uterine artery) –

supply vagina

f- inferior vesical artery - urinary bladder (in males)

g- Middle rectal artery – rectum

h- Internal pudendal artery.

The last two are at the end of internal iliac artery.

We must memorize the names only (branches of internal iliac)

In this system.

Paired branches:

Paired arteries divided into right and left while single arteries are not.

Paired branches: 1 front, 4back & 3 side

1- 1 front ---- testicular or ovarian artery at level L2

2- 4 back ---- lumbar arteries

3- 3 side of aorta

- Inferior phrenic. A

- Middle suprarenal. A

- Renal. A (at the level of L2 drain in kidney)

*Suprarenal gland is rich in blood supply (3 arteries)

Superior Suprarenal: from phrenic artery

Middle Suprarenal: from abdominal aorta

Inferior Suprarenal: from Renal A.

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Veins of the posterior abdominal wall

The most important vein in the posterior abdominal wall is inferior vena

cava.

inferior vena cava.

It is lateral to the abdominal aorta (at the right side).

It starts at the level of L5 on the right side.

It came from right and left common iliac veins and common iliac came

from external and internal iliac (opposite to the arteries).

It ends at inferior vena caval orifice (orifice in the diaphragm) at the

level of T8 in the right cupula of diaphragm and then directly drains to

the right atrium.

Azygous vein drain to the arch of azygous then superior vena cava and

finally to the right atrium.

As you know right atrium Receives deoxygenated blood from all the

body by three veins which are: superior vena cave, inferior vena cava

and coronary sinus from the heart.

The Tributaries of inferior vena cava: (opposite to the branches of the

artery)

-Renal vein.

-Testicular or ovarian vein from testis or ovaries.

-Lumbar veins (4 veins).

-Azygous vein from the posterior wall of abdomen.

-Suprarenal vein:

Right: drain directly to inferior vena cava.

Left: goes to left renal vein then to inferior vena cava.

-Phrenic veins from diaphragm.

-Hepatic veins from the liver (three).

We notice that single arteries are opposite to single veins. They drain to

the portal vein then to the liver.

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Portal vein

5 cm long (2 inches). Formed behind the neck of pancreas. Goes to the

liver then branches to right portal (cystic vein drains in it) and left

portal.

Tributaries:

Superior mesenteric.

Splenic

Inferior mesenteric (drains either in splenic of in the junction)

Gastric veins (Rt. & L).

Cystic vein.

From that we conclude that there is portal circulation (portal vein to the

liver) and systemic circulation (inferior vena cave to the heart).

Pay attention to ductus venosus which is closes after delivery and

converts to ligamentum. Also notice umbilical vein which make

ligamentum teres.

Relations of inferior vena cava:

Anterior:

coils of small intestine esp. the ileum.

First and third part of duodenum. (I.V.C and portal vein are posterior to

the first part of duodenum).

Head of pancreas.

Common bile duct.

Related to foramen of Winslow

Portal vein - lies in deep groove of liver

Tributaries of I.V.C: (from slides)

Two anterior visceral tributaries: the hepatic veins

Three lateral visceral tributaries: the right suprarenal vein (the left vein

drains into the left renal vein), renal veins, and right testicular or ovarian

vein (the left vein drains into the left renal vein)

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Five lateral abdominal wall tributaries: the inferior phrenic vein and four

lumbar veins.

Three veins of origin: two common iliac veins and the median sacral

vein.

Portal systemic anastomosis:

portal means portal vein. Systemic means going to inferior vena cava

then to the heart.

Is there connection between portal and systemic circulation?

No, there isn’t connection in normal people

Lower third of esophagus have systemic and portal drainage. Systemic

like azygous vein takes blood to superior vena cava while portal which is

left gastric vein goes to the portal. This site called portal systemic

anastomosis. The problem with this is when there is liver cirrhosis or

fibrosis as a result the blood supply of hepatocyte is stopped. Then

obstruction inside the liver takes place and that means that blood in

portal vein can’t pass and accordingly the blood goes back to its source.

For example, the blood in the left gastric vein goes back to the wall of

the esophagus in the lower third instead of portal vein. Then the blood

converges in the lower third where it meets the azygous vein so the

anastomosis between portal and systemic occurs. The latter connection

is due to portal hypertension and the veins become dilated tortuous and

engorged with blood and that may result in bleeding, so the patient is

.haematemesisvomiting blood this state called

In the past many people were dying from esophageal varices, but

nowadays it can be treated easily by entering coagulative materials or

ice by endoscope.

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Portal systemic anastomosis

Systemic circulation Portal circulation Name of clinical condition

Region

Esophageal branches of Azygos vein

Esophageal branch of left gastric vein

Esophageal varices Esophageal (lower third)

Middle rectal veins and inferior rectal veins (drains to I.V.C)

Superior rectal vein (drains to inferior Mesenteric then portal vein)

Hemorrhoids (fresh blood present in stool)

Rectal

Superficial epigastric veins

Paraumbilical veins Caput medusae (dilated and tortuous veins around umbilicus and make radial distribution*)

Paraumbilical

Renal vein, suprarenal vein, paravertebral vein, and gonadal vein

Right colic vein, middle colic vein, left colic vein

(no clinical name) Retroperitoneal

Inferior vena cava Left branch of portal vein

Patent ductus venosus

Intrahepatic

Bare area of liver Also makes connection between systemic and portal

circulation.

Read the table carefully.

The main reason of anastomosis is liver cirrhosis and fibrosis by bilharzial

infection, congenital by ductus venosus (stay opened) or heart disease.

*Radial distribution here means lines destined toward the umbilicus.

Lymphatics on the Posterior Abdominal Wall

Notice that lymph nodes in the GI track around blood vessels.

The lower limbs usually drain to inguinal lymph nodes (superficial and

deep). Around external iliac artery there is external iliac lymph nodes.

More abundant is present around internal iliac all pelvic viscera

converge in internal iliac lymph nodes.

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In general, there are two types of lymphatic in lymph nodes; afferent

and efferent.

In our case the efferent lymph nodes reach cisterna chyli.

Preaortic lymph nodes:

Celiac, superior mesenteric and inferior mesenteric lymph nodes around

the origin of the arteries. In other words, the organs from the lower

third of esophagus until upper half of anal canal drain to preaortic L.N.

After celiac L.N. we have efferent goes through intestinal trunk to

cisterna chyli.

Para-aortic (lumbar) lymph nodes:

They receive lymphatics from kidneys, suprarenal, testis in male, ovaries

and uterus in females. The efferent lymph vessels converge around

common iliac and form the right and left lumbar trunk then finally drain

to cisterna chyli.

There are two important trunks around aorta which are intestinal trunk

(at the two sides of aorta) and lumbar trunk. They end at cisterna chyli.

WHERE IS CISTERNA CHYLI?

This sac located in the midline on the right side of abdominal aorta.

Thoracic duct which is forty-five cm long arises from it. Thoracic duct is

beaded since it contains valves.

Thoracic duct ends at the beginning of left brachiocephalic vein (the

union internal jugular and subclavian veins). The duct is located at the

junction at the root of the neck.

Sorry for any mistakes

Don’t forget to refer to slides

“If you waIt for opportunItIes to occur, you wIll be one

of the crowd”

(Edward De Bono)

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