Vascular anatomy of the equine small colon.

This research article explores the vascular anatomy of the small colon in adult ponies. Using various techniques, the researchers found that the blood supply of the small colon comes primarily from the caudal mesenteric artery, with a network of interconnected arteries and veins supplying and draining the organ.

Research Methodology

• The researchers used 22 small colons from deceased adult ponies. They filled these colons’ vasculature with either latex or barium sulphate solution to map their internal structures.
• They studied the resultant anatomical maps using dissection, alkaline digestion of the latex-filled specimens, and microangiography – a type of medical imaging technique – of the barium sulphate-perfused samples. This allowed an in-depth view of the blood and vein network supplying the small colon.

Arterial Supply

• The study found that the primary source of blood supply to the small colon comes from the caudal mesenteric artery.
• This artery produces the left colic artery before eventually becoming the cranial rectal artery.
• These arteries form connecting (anastomosing) arcades – passages or paths that allow blood flow – which reduce in width the further they are along the small colon length.
• The terminal arteries originate from these arcades, invade the small colon wall, and give rise to a subserosal, an intermuscular, and a large submucosal plexus – a network of interlinked blood vessels – with common anastomoses between these layers.

Vein Drainage

• The venous, or deoxygenated blood, drainage mirrors the arterial blood supply closely in its path.
• However, at the origin of the drainage, near the portal vein, the left colic vein and caudal mesenteric vein separates from the arteries. Therefore, these veins do not directly parallel the corresponding arteries.

These findings could further the understanding of the vascular anatomy of the equine small colon, potentially contributing to more effective diagnosis and treatment of equine gastrointestinal conditions.