Ascending colon

The ascending colon is the initial segment of the colon, extending cranially from the cecocolic junction to the right colic flexure. It is relatively short and straight in the dog, and lies on the right side of the root of the mesentery.

Anatomical Course and Position

• Begins at the ileocolic orifice, where the ileum enters the colon, immediately cranial to the cecum.

• Passes cranially along the right dorsal abdominal wall, typically to the right of the cranial mesenteric artery.

• Terminates at the right colic flexure (also called the hepatic flexure), where it transitions into the transverse colon.

Topographical Relations

• Lies ventral to the caudal portion of the right kidney.

• Medial to the descending duodenum.

• The cecum is caudoventral to it.

• The transverse colon runs perpendicular to it, crossing from right to left cranial to the root of the mesentery.

Vascular Supply

• Supplied by the colic branch of the ileocolic artery, a branch of the cranial mesenteric artery.

Functional Notes

• Functions in water and electrolyte absorption, and fecal consolidation.

• Plays a minor role in microbial fermentation, compared to herbivores.