4. Spleen and the portal venous system.pptx

Question 1

What is the relation of the ribs to the spleen?

Answer 1

The spleen lies with ribs 9-11 to the left and posteriorly

Question 2

How thick is the spleen?
How long is it?
How wide is it?
Which ribs?
How much does it weigh?

HINT: 1,3,5,7,9,11

Answer 2

1,3,5,7,9,11 
The spleen is: 
1 inch thick; 
3 inches wide;                 	     5 inches long;
weighs 7oz (200g);
lies between the 9th and11th ribs

Question 3

Functions of the spleen?

Answer 3

1. Mechanical filtration of red blood cells
2. Active immune response through humeral and cell mediated pathways
3. Haematopoesis until 5th month of gestation

Question 4

What organs lie on/into the spleen?

Answer 4

Stomach in the gastric area
Left kidney in the renal area
Splenic flexure in the colic area

Question 5

The spleen is surrounded by peritoneum that was derived from the dorsal mesentery of the ______

Answer 5

The spleen is surrounded by peritoneum that was derived from the dorsal mesentery of the stomach

Question 6

Connections of the spleen?

What vessels are carried in each connection?

Answer 6

It is connected to the stomach by the Gastrosplenic ligament
Carries: Left gastro-epiploic and short gastric branches of the splenic artery (and equivalent veins)

It is connected to the posterior abdominal wall, adjacent to the left kidney, by the Lienorenal (Splenorenal) ligament
Carries: Splenic artery and vein alongside the tail of the pancreas

Question 7

Risk of rib 9-11 fracture?

Answer 7

Rupture spleen causing intraperitoneal haemorrhage

Question 8

What structure is at risk during removal of the spleen?

Answer 8

When removing the spleen, great care must be taken to avoid injuring the tail of the pancreas when ligating the splenic vessels

Question 9

Arterial supply of spleen?

Answer 9

The splenic artery is the largest branch of the coeliac artery
[It has a tortuous course as it runs along the upper border of the pancreas]
The artery then divides into about six branches, which enter the spleen at its hilum

Question 10

Venous drainage of spleen?

Answer 10

The splenic vein leaves the hilum and runs behind the tail and the body of the pancreas Behind the neck of the pancreas, the splenic vein joins the superior
mesenteric vein to form the portal vein (L1, Transpyloric Plane)

Question 11

Lymph drainage of spleen?

Answer 11

The lymph vessels emerge from the hilum and pass through a few lymph
nodes along the course of the splenic artery and then drain into the coeliac
nodes

Question 12

Nerve supply of spleen?

Answer 12

The nerves accompany the splenic artery and are derived from the coeliac
plexus (foregut T 5 to 9))

Question 13

5 parts of the pancreas

Answer 13

Uncinate process
Head
Neck
Body
Tail

Question 14

Where does the portal venous system drain?

Answer 14

lower 1/3 of oesophagus
Spleen
Pancreas
Gall bladder

Question 15

When the portal vein reaches the liver what does it do?

Answer 15

Branches and supplies the sinusoids, from which blood passes into the hepatic veins that join the inferior vena cava
In the sinusoids, the portal venous blood mixes with oxygenated blood from the hepatic artery

Question 16

What vessels unite to form the portal vein?

Answer 16

Splenic vein

Superior Mesenteric Vein

Question 17

Where does the left gastric vein drain before it directly drains into the portal vein?

Answer 17

Lower oesophagus

Left end of the lesser curve of the stomach

Question 18

What vessel joins the splenic vein and drains the hindgut?

Answer 18

The inferior mesenteric vein drains the hindgut and joins the splenic vein in very variable positions behind the pancreas, often joining the portal vein itself

Question 19

Which vessels drain into the portal vein?

Answer 19

Splenic vein ( + IMV)
SMV
Left gastric vein
Right gastric vein
Cystic vein

Question 20

Where does the right gastric vein drain before it directly drains into the portal vein?

Answer 20

Drains the right end of the lesser curve of the stomach directly to the portal vein

Question 21

What are the 4 sites of porto-systemic anastomosis?

Answer 21

1. At the lower third of the oesophagus
2. Halfway down the anal canal
3. The para-umbilical veins
4. The veins of the retroperitoneal ascending colon, descending colon, duodenum, pancreas and liver

Question 22

How does the lower third of the oesophagus act as a site of porto-systemic anastomosis?

Answer 22

At the lower third of the oesophagus, the oesophageal branches of the left gastric vein (portal tributary) anastomose with the oesophageal veins
draining the middle third of the oesophagus into the azygos veins (Varices)

Question 23

How does halfway down the anal canal act as a site of porto-systemic anastomosis?

Answer 23

Halfway down the anal canal, the superior rectal veins (portal tributary)
draining the upper half of the anal canal anastomose with the middle and inferior rectal veins that are systemic tributaries of the internal iliac and internal pudendal veins, respectively (Piles or Haemorrhoids)

Question 24

How does the para-umbilical act as a site of porto-systemic anastomosis?

Answer 24

The para-umbilical veins connect the left branch of the portal vein with the
superficial veins of the anterior abdominal wall (systemic tributaries). The
para-umbilical veins travel in the falciform ligament and accompany the ligamentum teres (Caput Medusae)

Question 25

How do veins of the retroperitoneal intestine, pancreas and liver act as a site of porto-systemic anastomosis?

Answer 25

The veins of the retroperitoneal ascending colon, descending colon, duodenum, pancreas, and liver (portal tributaries) anastomose with the renal, lumbar, and phrenic veins (systemic tributaries)

Question 26

The portal vein drains blood from the visceral organs to the liver
If this is stopped by a ‘blockage’ blood flows or ‘bypasses’ into the systemic circulation, usually causing the anastomotic veins to dilate.

Supra-hepatic causes?
Hepatic causes?
Infra-hepatic causes?

Consequences?

Answer 26

Supra-hepatic causes:
Cardiac disease
Hepatic vein thrombosis
IVC thrombosis

Hepatic causes:
-Cirrhosis (due to alcohol, hepatitis)

Infra-hepatic causes:

• Portal vein thrombosis
• Splenic vein thrombosis

Consequences

• Oesophageal varices
• Haemorrhoids
• Caput medusa

Question 27

Visceral branches on the abdominal aorta:
3 unpaired, anterior branches?
3 paired branches to viscera?

Answer 27

3 unpaired, anterior branches:

• Coeliac trunk T12
• Superior mesenteric artery L1
• Inferior mesenteric artery L3

3 paired branches to viscera:

• Middle suprarenal arteries
• Renal arteries L1
• Testicular and ovarian arteries (L2)

Question 28

Posterior branches of the abdominal aorta, supplying diaphragm / body wall?

Answer 28

1. Inferior phrenic arteries
2. Lumbar arteries
3. Median sacral artery

Question 29

The IVC is formed by the union of which vessels, at which location?

Answer 29

It is formed by the union of the common iliac veins behind the right common iliac artery at the level of L5 vertebra

Question 30

What are the tributaries of the IVC?

Answer 30

1. Two or three anterior visceral tributaries: the hepatic veins
2. Three lateral visceral tributaries: the right suprarenal vein (the left vein drains into the left renal vein), both renal veins, and the right gonadal vein (the left vein drains into the left renal vein)
3. Five lateral abdominal wall tributaries: the inferior phrenic vein and four lumbar veins
4. Three veins of origin: two common iliac veins and the median sacral vein