What is the blood supply to the duodenum (D1) until the upper rectum?

Blood Supply from Duodenum (D1) to Upper Rectum

Overview of Arterial Supply

The gastrointestinal tract from the duodenum through the upper rectum receives blood supply from three major arterial systems: the celiac trunk (supplying the duodenum), the superior mesenteric artery (supplying the small bowel and right colon), and the inferior mesenteric artery (supplying the left colon and upper rectum). 1

Duodenal Blood Supply

• The first portion of the duodenum (D1) receives its arterial supply primarily from branches of the celiac trunk, specifically through the gastroduodenal artery and its branches 1
• The duodenum represents a transition zone where upper gastrointestinal bleeding (proximal to the ligament of Treitz) meets the small bowel vascular territory 1

Small Bowel and Colonic Blood Supply

• The superior mesenteric artery is the primary blood supply for the small intestine and right colon, with branches including the ileocolic, right colic, and middle colic arteries 2
• The right colic artery may be absent in 2% of cases and commonly arises with the middle colic trunk in 52% of cases 2
• The middle colic artery is absent in 3% of cases and occurs as a separate branch in 44% of cases 2
• An important blood supply to the terminal ileum comes from the ileal artery; when absent, this creates a critical, poorly vascularized area 2

Left Colon and Rectal Blood Supply

• The inferior mesenteric artery divides into the left colic artery (ascending to the splenic flexure) and a descending branch that continues as the superior rectal artery 2
• The left colic artery may not reach the splenic flexure in some individuals 2
• The marginal artery (of Drummond) may be interrupted or weakly represented at the splenic flexure, creating a potential watershed area 2

Upper Rectal Blood Supply

• The superior rectal artery is the chief and main blood supply of the rectum, providing the primary arterial inflow to the upper two-thirds of the rectum 3, 2, 4
• The superior rectal artery forms a recto-sigmoid branch, an upper rectal branch, and then divides into right and left terminal branches 3
• Terminal branches of the superior rectal artery extend downwards and forwards around the lower two-thirds of the rectum to the level of the levator ani 3
• The superior rectal artery supplies the corpus cavernosum recti through a variable number of equally spaced twisting arteries 5

Collateral Circulation and Anastomoses

• The superior rectal artery has rich anastomoses with other rectal arteries (middle and inferior rectal arteries) 2
• The middle rectal artery, when present with appreciable diameter, supplies a limited part of the rectum in only 12% of specimens 3
• Intramural anastomoses exist primarily between the superior and inferior rectal arteries at the level of the dentate line in the submucosa, but extramural anastomoses between main rectal arteries are not typically observed 3, 4

Clinical Implications

• Understanding this vascular anatomy is critical for surgical planning, as ligation of vessels must preserve adequate collateral flow 2
• The splenic flexure represents a potential watershed area where the marginal artery may be weakly developed, requiring careful surgical technique 2
• Sudeck's point (the anastomosis between the left colic and superior rectal arteries) is not considered a critical vascular point 2