Abdo 9 Spleen, Portal Vein, IVC (Slides)

8/2/2019 Abdo 9 Spleen, Portal Vein, IVC (Slides)

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Abdomen 9: Spleen; Portal Vein; InferiorVena Cava

Illustrations from:Grays Anatomy, Standring et al, Elsevier, 39th Ed 2005Grays Anatomy for Students, Drake et al, Elsevier, 1st Ed 2005Core Anatomy Illustrated, Parkin et al, Hodder Arnold, 1st Ed 2007Grants Atlas of Anatomy, Agur, Dalley, Lippincott Williams and Wilkins, 12th Ed 2009


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Learning Outcomes

Understand the anatomy (position, function, relations, neurovascularsupply) of the spleen

Understand the anatomy (topography, position, function, relations) of theportal vein and its major tributaries

Understand the anatomy (topography, position, function, relations) of the

inferior vena cava (IVC) and its major tributaries

Be aware of the clinical implications of the anatomy of the spleen, portalvein and inferior vena cava


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The Spleen

In the adult the spleen lies like a large,flatcap mushroom against the

diaphragm from ribs 9-11 on the leftIts long axis is along the 10th rib

Odd Numbers up to11

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


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Functions of the spleen

1. Mechanical filtration of red blood cells

2. Active immune response through humeral and cell mediated pathways

3. Haematopoesis until 5th month of gestation

Relations

Diaphragm

Stomach

With characteristic notches onanterior edge between the two

Left kidney

Colon (splenic flexure)


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Lesser omentum

Gastrosplenicligament

Spleen

Visceral

peritoneum

Splenorenalligament

Left kidney

The spleen is surrounded byperitoneum that was derivedfrom the dorsal mesentery ofthe stomach

It is connected to the stomachby the Gastrosplenic ligamentthat carries the left gastro-epiploic and short gastricbranches of the splenic artery(and equivalent veins)

It is connected to the posteriorabdominal wall, adjacent to theleft kidney, by the Lienorenal

(Splenorenal) ligament thatcarries the splenic artery andvein alongside the tail of thepancreas


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The spleen is seen here adjacent to ribs9, 10 and 11 on the leftRib fractures may rupture the spleen,causing considerable intraperitoneal

haemorrhage

It would be interesting to know thecurrent thoughts on splenectomy as thetreatment of choice


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


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Another view to summarise splenic relations

Oesophagus

Diaphragm

Spleen

Tail of pancreas withsplenic artery above

Left kidney with renalvein and artery

Inferior mesenteric vein,

joining the splenic vein


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Spleen blood supply, lymph drainage and nerve supply

The splenic artery is the largest branch of the coeliac arteryIt 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 itshilum

The splenic vein leaves the hilum and runs behind the tail and the body ofthe pancreasBehind the neck of the pancreas, the splenic vein joins the superiormesenteric vein to form the portal vein

Lymph DrainageThe 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

Nerve SupplyThe nerves accompany the splenic artery and are derived from the coeliacPlexus (foregut T 5 to 9))


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Hepatic artery proper

Right gastric artery

Splenic artery

Left gastricartery

Short gastric arteries

Left gastro-omental artery

Right gastro-omental arteryAbdominal aorta

Posterior superior pancreaticoduodenal artery

Anterior superior pancreaticoduodenal artery

Gastroduodenal arteryDrake: Gray's Anatomy for Students, 2nd Edition.Copyright 0 2009 by Churchill Livingstone, an imprint of Elsevier, Inc. All rights reserved.


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Make a shopping list of

obvious relationsWhere is the splenic vein?


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Portal Venous System

In Summary

The portal vein drains blood from the lower third of the oesophagusto halfway down the anal canal

It also drains blood from the spleen, pancreas, and gallbladder

The portal vein enters the liver, branches and supplies thesinusoids, from which blood passes into the hepatic veins that jointhe inferior vena cava

In the sinusoids, the portal venous blood mixes with oxygenatedblood from the hepatic artery


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The SMV passes in the root of themesentery, anterior to the 3rd partof the duodenum and theuncinate process of the pancreas

The portal vein is about5 cm long and is formedbehind the neck of thepancreas by the union

of the splenic andsuperior mesentericveins (SMV)

It ascends to the right,behind the first part ofthe duodenum, andenters the lesseromentum

It then runs upward infront of the opening intothe lesser sac to theporta hepatis, where itdivides into right and leftterminal branches


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Drake: Gray's Anatomy for Students, 2nd Edition.Copyright 0 2009 by Churchill Livingstone, an imprint of Elsevier, Inc. All rights reserved.

Right hepatic artery

Left hepatic arteryHepatic artery proper

Portal vein

Gastroduodenal artery

Left gastric artery

Coeliac trunk

Splenic arteryRight gastric artery

Stomach

In the free edge of the lesseromentum, the portal vein liesbehind the hepatic artery,with the bile duct to the rightof the artery


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Elsevier. Drake et al: Gray's Anatomy for Students - www.studentconsult.com

Portal vein

Superior mesenteric vein

Ascending colon

Ileum

Stomach

Short gastnc veins

Spleen

Sigmoid colon

Rectum

Left gastric vein

Left gastro-omental veinSplenic vein

Inferior mesenteric vein

Descending colon

The left gastricvein drains thelower oesophagusand left end of the

lesser curve of thestomach directly tothe portal vein

The inferior mesentericvein drains the hindgut

and joins the splenic veinin very variable positionsbehind the pancreas,often joining the portalvein itself


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The cystic vein usuallydrains directly to the portalvein, but may drain to theliver Cystic

Vein

Right Gastric Vein

The right gastric veindrains the right end ofthe lesser curve of thestomach directly to theportal vein


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In this cadavericillustration, the stomach,lesser omentum andpancreas have beenremoved to show thetopography of the portalvein

Hepatic and cysticducts joining toform bile duct

Duodenum

1st Part

Oesophagus

Portal Vein formedfrom Splenic andSuperior Mesenteric

Hepatic arterydividing into left andright branches

SpleenandSplenic

Artery

Sit f t t i t i


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Sites of porto-systemic anastomosis

1. At the lower third of the oesophagus, the esophageal branches of the leftgastric vein (portal tributary) anastomose with the oesophageal veinsdraining the middle third of the oesophagus into the azygos veins (Varices)

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

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

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


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The sites are illustratedhere

The portal vein drains

blood from the visceralorgans to the liver

If this is stopped by ablockage blood flows orbypasses into thesystemic circulation,usually causing theanastomotic veins to dilate

1

4

3

2

Supra-hepatic causes

Cardiac diseaseHepatic vein thrombosisIVC thrombosis


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The normal

portal venouspressure is5 - 10mm Hg,

if elevatedabove this theterm portal

hypertensionis used


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Supra-hepatic causes Cardiac disease, Hepatic vein thrombosis,

IVC thrombosis


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Hepatic Causes CIRRHOSIS alcohol, hepatitis etc


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Infra-hepatic Causes Portal vein thrombosis, Splenic vein thrombosis


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Oesophageal varices

Haemorrhoids

Caput Medusae


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Inferior Vena Cava

The inferior vena cava conveysblood from the body below thediaphragm to the right atrium ofthe heart

It is formed by the union of thecommon iliac veins behind theright common iliac artery at thelevel of the fifth lumbar vertebra

It ascends on the right side ofthe aorta, pierces the centraltendon of the diaphragm at thelevel of T8, and drains into theright atrium of the heart

The entrance into the lesser sacseparates the inferior venacava from the portal vein


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Inferior Vena Cava: Tributaries

1. Two or three anterior visceraltributaries: the hepatic veins

2. Three lateral visceral tributaries:the right suprarenal vein (the leftvein drains into the left renal vein),both renal veins, and the rightgonadal vein (the left vein drains intothe left renal vein)

3. Five lateral abdominal walltributaries: the inferior phrenic veinand four lumbar veins

4. Three veins of origin: twocommon iliac veins and the mediansacral vein


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Elsevier. Drake et al: Gray's Anatomy for Students - www.studentconsult.com

Oesophagus

Diaphragm

Left suprarenal gland

Inferior vena cava

Right suprarenal gland

Left kidney

Abdominal aorta

UreterGonadal vessels

Right kidney

Hepatic Veins

IVC Relations(short right renal andsuprarenal veins)

Blunt trauma -liver, hepatic veinand IVC injury

IVC A t Right Common Iliac Artery crossing Left


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IVC

Right External IliacArtery and Vein,branching from rightcommon iliac

Aorta

Left CommonIliac Arteryand Vein(crossed byureter)

Right Common Iliac Artery crossing LeftCommon Iliac Vein and start of IVC

Left Renal Vein receivingSuprarenal and Gonadal

Veins before passingposterior to SMA

More IVC Relations


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Learning Outcomes

Understand the anatomy (position, function, relations, neurovascularsupply) of the spleen

Understand the anatomy (topography, position, function, relations) of theportal vein and its major tributaries

Understand the anatomy (topography, position, function, relations) of the

inferior vena cava (IVC) and its major tributaries

Be aware of the clinical implications of the anatomy of the spleen, portalvein and inferior vena cava

The End

Abdo 9 Spleen, Portal Vein, IVC (Slides)

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