Intestinal Arteries

The intestinal arteries are branches of the superior mesenteric artery (SMA) that supply blood to the jejunum, ileum, and portions of the large intestine. These arteries form a rich network of arcades and vasa recta that ensure efficient blood delivery to the rapidly metabolizing tissues of the gastrointestinal tract. Their branching pattern allows for collateral flow and segmental distribution, which is vital in maintaining perfusion even in partial arterial occlusion.

Structure

The intestinal arteries arise from the convex (left) side of the superior mesenteric artery. They consist of numerous branches that run between layers of the mesentery to reach the intestines. These arteries are classified into two main groups:

• Jejunal arteries: Typically 4–5 large branches to the jejunum
• Ileal arteries: 8–12 smaller branches to the ileum

These branches form a series of arterial arcades (loops), from which straight vessels called vasa recta extend to supply the intestinal wall.

Location

The intestinal arteries originate from the SMA at the level of L1 and travel within the mesentery toward the small intestine. Their anatomical path is described below:

Function

The intestinal arteries supply oxygenated blood to the small intestine, ensuring proper digestion and absorption of nutrients. Their main roles include:

• Jejunal supply: Provides high-flow blood delivery to the proximal small intestine, which has greater absorptive activity.
• Ileal supply: Supports the distal small intestine and transitions into ileocolic branches supplying part of the cecum.
• Collateral support: The arterial arcades form a network that helps preserve perfusion even if one branch is compromised.

Clinical Significance

The intestinal arteries are involved in several important clinical scenarios:

• Mesenteric ischemia: Occlusion of these arteries (usually due to SMA thrombosis or embolism) can lead to bowel infarction, a life-threatening emergency.
• Arterial arcades and vasa recta pattern: Helpful during surgical resections (e.g., for Crohn’s disease or tumors) to preserve sufficient blood flow to remaining bowel segments.
• Radiological imaging: CT angiography or mesenteric arteriography may show disrupted or narrowed intestinal arteries in ischemic bowel disease.
• Internal hernias or volvulus: Twisting of the mesentery can compromise these arteries, particularly in thin or elongated mesenteries.
• Anatomical variation: Some individuals have fewer arcades or unusually long or short vasa recta, which may influence surgical planning.

The intestinal arteries are essential for sustaining the metabolic and absorptive demands of the small intestine. Their branching pattern, rich collateralization, and clinical relevance make them a crucial component of mesenteric vascular anatomy.