Large Intestine Anatomy & Vascular Supply

Question 1

List the structures of the large bowel starting from the end proximal to the ileocecal valve.

Answer 1

Inferior to the ileocecal valve:
- cecum
- appendix
Superior to the ileocecal valve:
- ascending colon
- right colic (hepatic) flexure
- transverse (middle) colon
- left colic (splenic) flexure
- descending colon
- sigmoid colon
- rectum
- external anal sphincter

Question 2

Name the most superior artery that branches off the aorta to supply the large colon (midgut).

Answer 2

The superior mesenteric artery (SMA) is in the midsection of the digestive tract (midgut). It originates from the aorta between the celiac artery and renal arteries.

Question 3

Name the three major anterior branches of the abdominal aorta

Answer 3

Coeliac trunk (CT / CA)
Superior Mesenteric Artery (SMA)
Inferior Mesenteric Artery (IMA)

Question 4

Describe the origin of the Superior Mesenteric Artery (SMA)

Answer 4

It arises anteriorly from the abdominal aorta at the level of the L1 vertebrae, immediately inferior to the origin of the coeliac trunk.

Question 5

What is the Transverse Mesocolon?

Answer 5

The part of the mesentery that extends to the transverse colon is referred to as the transverse mesocolon. It envelopes the transverse colon as the serosa, therefore, suspending the transverse colon for the posterior abdominal wall. The transverse mesocolon houses the vessels which supply the transverse colon.