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MA143

Abdominal Viscera - Vascular Approach

M.Pizzimenti, Ph.D.

Reading: MA 139-201

Objectives:

• Classify visceral organs as belonging to the foregut, midgut, or hindgut

• Describe how the gut is supported during development and outline the major

rotations of the GI

• Sketch the arterial supply to the foregut, midgut, and hindgut

• Sketch the venous return of the GI tract via the portal system

• Use the areas of portal/caval anastomoses to infer clinical presentation of portal

hypertension

• Predict the normal vascular supply and drainage for each visceral organ

• Outline the autonomic nervous supply to the foregut, midgut, and hindgut

• Trace the lymphatic drainage of each visceral organ

• Describe the concept of referred pain

• Summarize how pain from the gallbladder, appendix, pancreas, stomach, small

intestine, or colon may present in a patient.

Big Picture

Foregut

• Esophagus, stomach,

liver (4 lobes),

gallbladder (biliary

system), pancreas,

duodenum (2/3)

Midgut

• Distal duoden, jejunum,

ileum, ascending colon,

transverse colon

Hindgut

• Descending colon,

sigmoid colon, anorectal

canal

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MA140

GA116-17; MA140,142

Peritoneum

• visceral

peritoneum

- covers organs

- supplied by

autonomic

nn. and

blood/lymph

vessels of

viscera

• parietal

peritoneum

- lines inner

abdominal

walls

- supplied by

somatic nn.

and

blood/lymph vessels of abd.pelvic wall

• mesentery

- double layer fold through which vessels and nerves pass >anchor to post.

abdominal wall

• omentum = double fold of peritoneum that joins two visceral organs

- greater > greater curvature of stomach to transverse colon

- lesser > lesser curve of stomach to inf. Liver and constitutes the

hepatoduodenal, hepatogastric ligts.

• Greater Sac

- main part of peritoneal cavity

• Lesser Sac (omental bursa)

- post. to stomach via epiplioc foramen (of Winslow)

- sup. recess limited by diaphragm and coronary ligts of

liver

- inf. recess limited by sup. part of greater omentum

• Transverse mesocolon

- mesentery anchoring transverse colon to posterior

wall

• Retroperitoneal viscera

- viscera not completely surrounded by peritoneum

- kidneys, adrenals,

- parts of pancreas, duodenum, ascending & descending

colon - these organs have no mesentery, therefore not

completely surrounded by visceral peritoneum

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MA144 Right

GI Arterial Tree

3 main arteries arise from the anterior aspect of the aorta: celiac trunk, superior

mesenteric a., inferior mesenteric a.

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1

2

3 4

5 6

7

8

9

10

11

modified from GA 2.27-29

*

*

MA 154

Celiac Trunk (Foregut

supply

Splenic (1)

• Passes post. to stomach, ‘curly’

• Gives off left gastroepiploic(omental)

(11) to supply greater curvature of

stomach

Hepatic (3)

• Common hepatic proper (4) travels within

gastroduodenal ligament

• L/R hepatic (5)

• Cystic (6) branches of R hepatic a.

• Right gastric (7)

Supplies lesser curvature of stomach,

anastomose with (2)

Left gastric (2)

• Supplies lesser curvature of stomach

• Gives off esophageal branches

Gastroduodenal (8)

• Right gastroepiploic(omental) (9)

- Supplies greater curvature of stomach, will

anastomose with (11)

• Sup. pancreaticoduodenal (10)

Superior Mesenteric a. (midgut)

• just inferior 1-2 cm inferior to

celiac trunk

• middlecolic to hepatic (right

colic) flexure

• marginal supplies transverse

colon and will anastomose with

L colic

• right colic to ascending colon

• ileocolic to ileum and cecum

• appendicular branch

• ileal and jejunal branches

• inf. pancreaticoduodenal

supplies portion of duodenum

and pancreas bridging foregut

and midgut

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MA146

Inferior Mesenteric a. (Hindgut)

• 4-5 cm above aortic bifurcation into common iliac aa.

• superior rectal, end of the street

• sigmoidal, 3-5 branches supply sigmoid colon

• left colic, supplies descending colon with multiple branches

- will anastomose with marginal a

Note relationships

• SMA ant. to distal duodenum and renal vein

• *weak anastomotic areas

Portal Venous system

Portal v. drains venous blood

from the GI tract and

accessory organs to the

sinusoids of the liver > drains

into systemic system via

hepatic vv. into IVC

• named veins, same as

arteries

• gastric vv., cystic and

small duodenal vv.

usually drain into portal

v.

• inf. mesenteric, L.

gastro-omental, and

pancreatic vv drain into

splenic v.

• R. gastro-omental,

pancreatico-duodenal,

jejunal, ileal, R. and

middle colic drain into

superior mesenteric

Portal-Caval Anastomoses

1. Gastroesophageal

a. esophageal/left gastric v.

2. Anorectal

a. inf. & middle rectal/superior rectal

3. Paraumbilical

a. superficial epigastric/paraumbilical

4. Retroperitoneal

a. retroperitoneal (lumbar)

b. R & L colic branches

c. ileocolic branches

4

1

3

2

6

MD279

MA33

GA161,

MA162

Portal Hypertension

venous flow through liver is reduced

• vv. contain no valves, therefore retrograde flow possible

• pressure increase and produces varicose vv.

• anastomotic vv. may dilate and rupture

- paraumbilical site - caput medusae

- bleeding from esophageal varices at the distal end of

esophagus is often severe and may be fatal

• involved) the greater the risk for multiple organ involvement

• cancerous cell growths may permeate lymph vessels and form cellular emboli -

spread to other regions.

GI Lymphatics

lymphatic vessels most closely related to the arterial pathway (and are most often so

named)

From the regional (organ) nodes to the preaortic nodes (or cisterna chyli) and then into

thoracic duct.

• Ascending colon

- paracolic & epicolic, right colic, superior mesenteric, thoracic duct.

Discuss lymphatic flow from any organ

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Abdominal Viscera Lymphatic Pathway Generalizations Organ

Lymph node

Terminal

Esophagus

Left gastric

Celiac

Stomach

Gastric and gastroepiploic

Celiac

Spleen

Pancreaticosplenic

Celiac (superior mesenteric)

Pancreas

Pancreaticosplenic, pyloric

Celiac, Superior mesenteric, Hepatic

Liver (major lymph producer)

Hepatic

Celiac

Gallbladder

Cystic, Hepatic

Celiac

Duodenum

Pancreaticoduodenal

Pyloric (gastroduodenal)

Superior mesenteric

Celiac

Jejunum

Ileum

Mesenteric

Mesenteric and ileocolic

Superior Mesenteric

Ascending Colon

Paracolic and right colic

Superior Mesenteric

Transverse Colon

Paracolic and Middle Colic

Superior Mesenteric

Descending colon Paracolic and left colic Inferior Mesenteric

(Superior Mesenteric at splenic flexure)

Rectum

Pararectal (superior portion)

Internal iliac (inferior portion)

Inferior mesenteric (+ lumbar)

lumbar

Autonomic Nervous Supply

Sympathetics

• greater (T5-9), Lesser (T10,11), least (T12) >

preganglionic

• synapse in one of three preaortic ganglia

• celiac (1)

- foregut

• superior mesenteric (2)

- midgut

• inferior mesenteric (3)

- distal midgut & renal structures

- lumbar and sacral splanchnics supply hindgut

Parasympathetics

• vagus n. (CN X) > preganglionic

- foregut & midgut

• pelvic splanchnics (S2-S4)> preganglionic

- hindgut

• synapse within (near) target organ

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MD248

Visceral Sensation

Sympathetics

Pain (ischemia, chemical irrtation, etc.) is mediated through the sympathetic system

afferents travel with the splanchnic nn and travel through the ganglia chain

Cell bodies of the afferent fibers are located in the DRG at the appropriate level

dermatomes give you information about what might be happening at the visceral level

Parasympathetics

• distention (bladder, GI, uterine) is mediated through parasympathetic system

• cell bodies of the afferent fibers are located in the sensory ganglia of the

appropriate cranial nerve

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Referred Pain

‘Confusion’ in the CNS

• phenomenon where a region that has no direct injury ‘senses pain’ as a result of

some type of visceral irritation.

• dull and poorly localized

Anatomical foundation

• ANS afferent fibers (sympathetics for pain) share somatic pathways to spinal cord

• the brain ‘perceives’ the pain as related to the somatic area (i.e., referred to the

dermatome)

EXAMPLE Biliary Colic & Referred Pain

• gall stone lodged in bile duct

• nerve supply to foregut?

• dermatome region?

• diaphragm innervation?

• dermatome region?

Chart (MA199; GA169)

MA = Moore, KL and Agur, AMR. 2007. Essential Clinical Anatomy (3rd Ed), Lippincott Williams &

Wilkins

MD = Moore, KL and Dalley, A. 1999. Clinically Oriented Anatomy (4th Ed), Lippincott Williams &

Wilkins

GD = Tank, PW, 2005. Grant’s Dissector (13th Ed), Lippincott Williams & Wilkins

GA = Agur AMR and Dalley, A 2005. Grant’s Atlas of Anatomy (11th Ed), Lippincott Williams &

Wilkins

Unlabelled images © LifeArt

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Embryology Overview

MA 166