THE INFERIOR MESENTERIC ARTERY

Question 1

THE INFERIOR MESENTERIC ARTERY?

Answer 1

• The inferior mesenteric artery (IMA) is a major branch of the abdominal aorta.
• It supplies arterial blood to the organs of the:
  
  • hindgut
  • the distal 1/3 of the transverse colon,
  • splenic flexure,
  • descending colon,
  • sigmoid colon and
  • rectum.

Question 2

Major Branches?

Answer 2

There are three major branches that arise from the IMA:

• the left colic artery,
• sigmoid artery and
• superior rectal artery.

Left Colic Artery supplies:

• distal 1/3 of the transverse colon and the descending colon
• the psoas major muscle
• left ureter
• left internal spermatic vessels
• before dividing into ascending and descending branches:

Ascending branch:

• It supplies the distal 1/3 of the transverse colon
• upper aspect of the descending colon.

Descending branch:

• supplies the lower part of the descending colon
• anastamoses with the superior sigmoid artery

Sigmoid Arteries:

• supplies the descending colon
• and the sigmoid colon. There are typically 2-4 branches

Superior Rectal Artery:

• The superior rectal artery is a continuation of the inferior mesenteric artery
• supplies the rectum.

At the S3 vertebral level:

• the artery divides into two terminal branches
• one supplying each side of the rectum.
• Within the walls of the rectum, smaller divisions of these branches eventually communicate with the middle and inferior rectal arteries.