Vessels of the Gut: Sup. Mesenteric A

Question 1

Describe Course of Superior mesenteric A

Answer 1

1. originates from Abdominal Aorta opposite L1 vertebra
2. Descends between 2 Vein coming from the left side: Splenic vein above origin & left Renal Vein below origin
3. Descend in front of uncinate process of Pancreas then in front of 3rd part duodenum
4. enters root of small intestine mesentery with superior mesenteric vein on its right
5. Descends to the right side inside the mesentery, crossing over:
   * Abdominal Aorta
   * IVC
   * Right Psoas Major
   * Right ureter
   * Right Gonadal Vessels
   * Right genitofemoral N

throught its course surrounded by sup. mesenteric plexus of nerves

Question 2

Origin of superior mesenteric A

Answer 2

from abdominal aorta opposite L1 vertebra, 1 cm below origin of Coeliac trunk

Question 3

Termination of Superior mesenteric Artery

Answer 3

at ileo-caecal junction by anastomosing with its ileo-Colic branch

Question 4

Enumerate branches of Superior mesenteric A

Answer 4

5 Arteries:
* Middle Colic A
* Right Colic A
* Ileocolic A
* Inferior Pancreaticoduodenal A
* Jejunal & ileal branches

Question 5

Origin Course branches & distribution of Middle Colic A

Answer 5

O: originates from sup. mesenteric A just below body of pancreas

Course: It runs in the transverse mesocolon & divides into right & left branches:
* Right branch of middle colic A anastomoses with Ascending branch of right Colic A
* Left Branch of middle Colic A anastomoses with Ascending branch of Superior Left Colic A

Distribution: supplies middle 1/3 of Transverse Colon

Question 6

Origin, Course & distribution of Inferior pancreatico-duodenal A

Answer 6

O: Arises from sup. mesenteric A as it crosses uncinate process

Course : Runs in the groove between head of pancreas & duodenum, & ends by anastomosing with Sup. pancreaticoduodenal A (branch from Hepatic A)

Distribution: supplies Lower 1/2 Duodenum + lower 1/2 Head pancreas + Uncinate process

Question 7

Origin, Course, branches distribution of Right Colic A

Answer 7

O: Arises from the middle Concave surface of the Sup. mesenteric A

Course: descends to the right retroperiotealy, crossing over Right Psoas Major, Right Ureter, Right Gonadal vessels, ends by dividing into Ascending & descnding branches

Branches:
* Ascending branch of Right Colic A: Anastomose With right branch of middle Colic A
* Descending branch of Right Colic A: Anastomose with Ascending branch of Iliocolic A

Distribution: Supplies upper 2/3 Ascending Colon + Right (hepatic) colic Flexure

Question 8

Origin, Course, branches distribution of IleoColic A

Answer 8

O: Arises from lower part of Concave surface of Sup. mesenteric A

Course: It runs to the right retroperiotnealy, ends by dividing into Ascending & descnding branch

Branches:
* Ascedning br. of Ileocolic A: anastomoses with Descending br. of middle Colic A
* Descending br. of Ileocolic A: anastomoses with termination of sup. mesenteric A itself

Question 9

Branches from Anatomoses of Descending br of Ileocolic A with Sup. mesenteric A

Answer 9

• Ascending br.: supply lower 1/3 ascending colon
• Anterior & posterior Caecal Arteries: supply Caecum
• Appendicular A: supply appendix
• Ileal branch: to terminal part of ileum

Question 10

Jejunal & Ileal branches of Sup. mesenteric A arise from

Answer 10

Convex left side of the artery

Question 11

Describe Jejunal & Ileal branches

Answer 11

they divide repeatedly inside mesentery of small intestine, forming arterial Arcades, then give straight end arteries called Vasa Recta

Question 12

Difference in arcades between Jujenal & ileal branches

Answer 12

• Arterial Arcades of Jejunal branches are longer & less neumerous than that of ileal branches