Question 7

College Answer

This question was answered best if the main arteries and veins were discussed first and then their corresponding supply outline in reasonable detail. Very few candidates were able to achieve this. Listing the names of vessels with no context and in a random non-sequential order did not attract many marks. The physiology of the blood supply to the liver also did not attract marks.

Discussion

The major arterial vessels and their branches are:

• Coeliac trunk
  • Left gastric artery
  • Common hepatic artery
  • Splenic artery
• Superior mesenteric artery
  • Inferior pancreaticoduodenal artery
  • Intestinal (jejunal and ileal) arteries
  • Ileocolic artery
  • Right colic artery
  • Middle colic artery
• Inferior mesenteric artery
  • Left colic artery
  • Sigmoid arteries
  • Superior rectal artery

The structures supplied by each branch are:

• Coeliac trunk:
  • Abdominal part of the oesophagus
  • Stomach
  • Superior half of the duodenum
  • Liver
  • Superior half of the pancreas
  • Spleen
• Superior mesenteric artery:
  • Intestine, from the lower half of the duodenum down to the splenic flexure of the large intestine
• Inferior mesenteric artery:
  • Colon, from the splenic flexure down to the sigmoid and superior portion of the rectum

Venous structures:

• Oesophagus is drained by branches of the azygous veins and the inferior thyroid vein
• Mesenteric circulation drains via the superior and inferior mesenteric vein
  • These two vessels are then joined by the splenic vein
  • These form the portal vein
  • This then splits to form the right and left branches in the liver
  • From the portal vein, blood drains via the hepatic vein into the inferior vena cava
• Lower third of the rectum and anus drain into the middle rectal vein, which drins directly into the IVC

Geboes, Karel, Karen P. Geboes, and Geert Maleux. "Vascular anatomy of the gastrointestinal tract." Best Practice & Research Clinical Gastroenterology 15.1 (2001): 1-14.

Kornblith, Paul L., Scott J. Boley, and Brian S. Whitehouse. "Anatomy of the splanchnic circulation." Surgical Clinics of North America 72.1 (1992): 1-30.

Rosenblum, Jordan D., Catherine M. Boyle, and Lewis B. Schwartz. "The mesenteric circulation: anatomy and physiology." Surgical Clinics 77.2 (1997): 289-306.