Vessel
Rectal arteries
Overlapping rectal and anal arterial territories
High-yield
Superior rectal belongs to the inferior mesenteric system; middle and inferior rectal belong to the internal iliac system. The pectinate line remains an important regional landmark, not an impermeable arterial boundary.
Overview
The rectum receives its main arterial inflow from the superior rectal continuation of the inferior mesenteric artery. Variable middle rectal vessels add pelvic inflow, while inferior rectal branches of the internal pudendal artery chiefly supply the distal anal region. Connections between these territories provide overlap rather than three completely separate zones.
Reference facts
- Origin
- Superior rectal: inferior mesenteric artery. Middle rectal: variable internal iliac branches, often internal pudendal or inferior gluteal. Inferior rectal: internal pudendal artery.
- Course
- Superior rectal descends behind the rectum and divides into mural branches; middle vessels approach laterally; inferior vessels cross the ischioanal fat toward the anal canal.
- Branches
- Superior rectal branches divide further within the rectal and upper anal walls; middle and inferior branches join the regional vascular network.
- Supplies
- Rectal wall and upper anal canal mainly from superior rectal inflow; variable middle contributions; distal anal canal and adjacent sphincter/perianal tissues from inferior rectal branches.
- Drains to
- Corresponding superior rectal veins reach the portal circulation through the inferior mesenteric vein; middle and inferior rectal veins reach systemic pelvic veins.
Clinical correlation
Middle rectal arteries differ in presence, origin and size. Collaterals can preserve distal bowel perfusion after interruption of a vessel, but adequate perfusion cannot be assumed from the standard diagram alone.
Frequently asked questions
Where do the rectal arteries originate?
Superior rectal: inferior mesenteric artery. Middle rectal: variable internal iliac branches, often internal pudendal or inferior gluteal. Inferior rectal: internal pudendal artery.
What do the rectal arteries supply?
Rectal wall and upper anal canal mainly from superior rectal inflow; variable middle contributions; distal anal canal and adjacent sphincter/perianal tissues from inferior rectal branches.
Where do the rectal arteries drain to?
Corresponding superior rectal veins reach the portal circulation through the inferior mesenteric vein; middle and inferior rectal veins reach systemic pelvic veins.
What are the branches of the rectal arteries?
Superior rectal branches divide further within the rectal and upper anal walls; middle and inferior branches join the regional vascular network.