Vessels of the Gut: Inf. Mesenteric A

Question 1

Origin of Inferior mesenteric Artery

Answer 1

From Abdominal Aorta at** level L3 vertebra**, behind 3rd part duodenum 3cm above end of Aorta

IMA= L3, 3rd part duodenum, 3cm above aorta end, 3 branches

Question 2

Course of Inferior mesenteric Artery

Answer 2

1. It descends downwards to the left retroperitonealy
2. First it’s in front of Aorta, then it is left to Aorta
3. Just medial to left ureter, it crosses left common iliac A
4. as soon as it crosses LCIA, it enters Sigmoid mesocolon & become superior rectal A

Question 3

Superficial (anterior) relations of Inf. Mesenteric A

Answer 3

• 3rd part Duodenum
• Peritoneum

Question 4

Deep (posterior) relations of Inf. Mesenteric A

Answer 4

• Abdominal Aorta
• Left Psoas Major
• Left Common Iliac A
• Left Sympathetic trunk

Question 5

Lateral relations of Inf. Mesenteric A (left side relations)

Answer 5

• Inferior mesenteric V
• Left ureter

Question 6

Medial (right side) relations of Inf. Mesenteric A

Answer 6

lower part of Aorta

Question 7

Enumerate branches of Inferior mesenteric A

Answer 7

3 branches:
* Sup. left Colic A
* Inf. Left Colic A (sigmoid A)
* Sup. Rectal (terminal)

Question 8

Course of Superior left Colic A

Answer 8

1. passes upwards & to the left towards descending Colon
2. (like Right Colic A) it crosses (lt) psoas major, (lt) ureter, (lt) gonadal vessels
3. It then divides into Ascending & descending Branches

Question 9

Branches of Sup. Left Colic A & Distribution

Answer 9

• Ascending Br. of sup. left Colic A: anastomose with left branch of middle Colic A
• Descending br. of Sup. left Colic A: anastomose with Highest sigmoid A

Distribution: supplies left 1/3 of transverse colon + left (splenic) Colic flexure + upper part descending colon

Question 10

Course & distribution of Inferior Left Colic (Sigmoid) Arteries

Answer 10

Course: they descend in lateral limb of sigmoid mesocolon, anastomosing above with sup. left colic A (Descending br.) & below with Sup. Rectal A

Distribution: supply Lower part Descending Colon + Sigmoid Colon

Question 11

Course of Superior Rectal A

Answer 11

1. Downwards terminal continuation of Inf. Mesenteric A
2. It run in medial Limb of Sigmoid mesocolon as far as 3rd sacral vertebra
3. then runs along posterior wall of rectum
4. it peirces Rectum & upper 1/2 anal canal & anastomeses with Inferior & middle rectal Arteries

Question 12

Distribution of Superior rectal Arteries

Answer 12

• Rectum
• upper 1/2 of anal canal