The abdominal aorta supplies the abdomen with blood vessels that branch into three main arteries: (1) The celiac trunk which branches further into the left gastric, splenic, and common hepatic arteries. (2) The superior mesenteric artery which supplies the small intestine and branches into jejunal, ileal, and colic arteries. (3) The inferior mesenteric artery which supplies the descending colon, sigmoid colon, and rectum through branches like the left colic and superior rectal arteries. Venous drainage of the abdominal organs is carried by the portal vein, formed by the union of the splenic and superior mesenteric veins. It delivers blood to the liver

1. Abdomen Part 3
Themba Hospital FCOG(SA) Part 1 Tutorials
By Dr N.E Manana

2. Arterial supply
• The abdominal aorta begins at the aortic hiatus of the diaphragm,
anterior to the lower boarder of T12
• It descends anterior to the vertebral bodies and by the time it ends at
L4 it is slightly to the left of the midline
• It terminates as the two common iliac arteries

3. Anterior branches of the abdominal aorta
• The abdominal aorta has anterior, lateral and posterior branches
• The 3 anterior branches, (A) Celiac trunk, (B) Superior mesenteric and
(C) Inferior mesenteric arteries
(A) Celiac trunk
• It arises immediately below the aortic hiatus of the diaphragm
anterior to L1
• It immediately divides into 1. left gastric, 2. Splenic and 3. Common
hepatic arteries

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5. • 4.122

6. Branches of the Celiac trunk
1. Left gastric artery
• Smallest branch, it ascends to the cardioesophageal junction and sends
oesophageal branches upward
• Continue upwards to anastomose with branches of the thoracic aorta
• The artery turns to the right and descends along the lesser curvature of the
stomach in the lesser omentum and anastomose with the right gastric artery
2. Splenic artery
• Largest branch, moves along the superior border of the pancreas, travels in the
splenorenal ligament
• Gives branches to supply the pancreas, gives off short gastric arteries which pass
via the gastrosplenic ligament to supply the fundus of the stomach

7. Branches of the Celiac trunk
2. Splenic artery (continued)
• It gives off the left gastro-omental artery which runs along the greater
curvature of the stomach and anastomoses with the right gastro-omental
artery
3. Common hepatic artery
• It runs to the right and divides into the hepatic artery proper and the
gastroduodenal artery
• The hepatic artery proper ascends toward the liver in the free edge of the
lesser omentum, divides into the R and L hepatic arteries
• The gastroduodenal artery may give off the supraduodenal artery before
descending posterior to the duodenum, an devides into the R gastro-
omental artery and the superior pancreaticoduodenal artery

8. • 4.97

9. • 4.124

10. Superior mesenteric artery
• The superior mesenteric artery supplies the midgut
• The superior mesenteric artery is crossed anteriorly by the splenic
vein and the neck of the pancreas
• Posterior to the artery are the left renal vein, the uncinate process of
the pancreas, and the inferior part of the duodenum
• After giving off its first branch (the inferior pancreaticoduodenal
artery), the superior mesenteric artery gives off jejunal and ileal
arteries on its left

11. • 4.126

12. Superior mesenteric artery branches
1. Inferior pancreaticoduodenal artery
• First branch of the superior mesenteric artery
• It divides immediately into anterior and posterior branches
• Superiorly, these arteries anastomose with anterior and posterior
superior pancreaticoduodenal arteries
2. Jejunal and ileal arteries
• Arising on the left is a large number of jejunal and ileal arteries
• Form anastomosing arches or arcades as they pass outward to supply
the small intestine via the mesentery

13. • 4.127

14. Superior mesenteric artery branches
3. Middle colic artery
• First of the three branches from the right side
• Arising as the superior mesenteric artery emerges from beneath the
pancreas
• The right branch anastomoses with the right colic artery while the left
branch anastomoses with the left colic artery
4. Right colic artery
• is the second of the three branches from the right side
• It is an inconsistent branch, and passes to the right in a retroperitoneal
position
• Nearing the colon, it divides into a descending branch, and an ascending
branch

15. Superior mesenteric artery branches
4. Ileocolic artery
• The final branch arising from the right side
• This passes downward and to the right toward the right iliac fossa
where it divides into superior and inferior branches
• The inferior branch continues toward the ileocolic junction, dividing
into colic, cecal, appendicular, and ileal branches
• The superior branch passes upward along the ascending colon to
anastomose with the right colic artery

16. Inferior mesenteric artery
• The anterior branch of the abdominal aorta that supplies the hindgut
• It is the smallest of the three anterior branches, arises anterior to the
body of vertebra LIII
• Initially, the inferior mesenteric artery descends anteriorly to the
aorta and then passes to the left as it continues inferiorly
• Its branches include the left colic artery, several sigmoid arteries, and
the superior rectal artery.

17. Inferior mesenteric artery branches
1. Left colic artery
• First branch of the inferior mesenteric artery
• It ascends retroperitoneally, dividing into ascending and descending
branches:
• The ascending branch passes anteriorly to the left kidney, then enters
the transverse mesocolon
• it anastomoses with branches of the middle colic artery
• The descending branch passes inferiorly, supplying the lower part of
the descending colon, and anastomoses with the first sigmoid artery

18. • 4.128

19. Inferior mesenteric artery branches
2. Sigmoid arteries
• Consist of two to four branches, which descend to the left, in the sigmoid
mesocolon, to supply the lowest part of the descending colon and the
sigmoid colon
• These branches anastomose superiorly with branches from the left colic
artery and inferiorly with branches from the superior rectal artery
3. Superior rectal artery
• Terminal branch of the inferior mesenteric artery it descends into the pelvic
cavity in the sigmoid mesocolon, crossing the left common iliac vessels
• Opposite vertebra SIII, the superior rectal artery divides , the two terminal
branches descend on each side of the rectum

20. • 4.129

21. Venous drainage
• Venous drainage of the spleen, pancreas, gallbladder, and abdominal
part of the gastrointestinal tract, except for the inferior part of the
rectum, is through the portal system of veins
• Which deliver blood from these structures to the liver
• Once blood passes through the hepatic sinusoids, it passes through
progressively larger veins until it enters the hepatic veins, which
return the venous blood to the inferior vena cava just inferior to the
diaphragm

22. Portal vein
• It is formed by the union of the splenic vein and the superior
mesenteric vein posterior to the neck of the pancreas at the level of
vertebra LII
• The portal vein passes posterior to the superior part of the
duodenum and enters the right margin of the lesser omentum
• On approaching the liver, the portal vein divides into right and left
branches, which enter the liver parenchyma

23. • 4.131

24. • 4.133

26. Splenic vein
• The splenic vein forms from numerous smaller vessels leaving the hilum of
the spleen
• It passes to the right, passing through the splenorenal ligament
• Posterior to the neck of the pancreas, the it joins the superior mesenteric
vein to form the portal vein
• Tributaries to the splenic vein include: short gastric veins, the left gastro-
omental vein, pancreatic veins, and usually the inferior mesenteric vein

28. Innervation
• Abdominal viscera are innervated by both extrinsic and intrinsic
components of the nervous system
• Extrinsic innervation involves receiving motor impulses from, and sending
sensory information to, the central nervous system
• Intrinsic innervation involves the regulation of digestive tract activities by a
generally self-sufficient network of sensory and motor neurons
• The visceral efferent fibers are part of the sympathetic and
parasympathetic parts of the autonomic division of the peripheral nervous
system.

29. Innervation
• Structural components serving as conduits for these afferent and
efferent fibers include posterior and anterior roots of the spinal cord,
respectively
• And the sympathetic trunks, splanchnic nerves carrying sympathetic
fibers (thoracic, lumbar, and sacral parasympathetic fibers , the
prevertebral plexus and the vagus nerves [X].
• The enteric nervous system consists of motor and sensory neurons in
two interconnected plexuses in the walls of the gastrointestinal tract

30. Sympathetic trunks
• 4.135

31. • 4.136

32. • 4.138

33. • 4.139

34. Thank you