Anatomy Correlations

What kind of organ is the Aorta? Why is this relevant for AAA

Aorta is retroperitoneal
→ because it is retroperitoneal, it can develop fistula with other retroperitoneal organs
→ Abdominal Aorta Aneurysms most commonly occur at the 3rd portion of the duodenum resulting in bright red rectal bleeding

What are the retroperitoneal organs?

being retroperitoneal means that an organ is located behind the peritoneum
SAD PUCKER
→ Suprarenal (adrenal glands)
→ Aorta
→ Duodenum (2nd and 3rd segments)
→ Pancreas
→ Ureters
→ Colon
→ Kidney
→ Esophagus
→ Rectum

What is the key point about the Superior Mesenteric Artery in terms of anatomy

1) the Superior Mesenteric Artery comes off of the abdominal aorta at an acute angle at the origin of the aorta
→ this sharp angle means that this is a common site of plaque formation

2) the Superior Mesenteric Artery is located at the 3rd portion of the duodenum and aorta
→ when someone loses weight the angle can become more acute between the SMA and the aorta, crushing the duodenum and renal vein

What are watershed zones?

Watershed zones are areas of tissues that lie between two major arterial blood supplies
→ the splenic flexure, rectal sigmoid junction, and the ileocolic junction is a watershed zone as it gets supply from the SMA and IMA as seen above
→ this means that these areas are at high risk of developing ischemia

What is important to know about the gastric duodenal artery

Gastric Duodenal Artery is located near the pylorus, first part of the duodenum, head of the pancreas, and common bile duct
→ because of this, the gastric duodenal artery is susceptible to bleeding and injury whenever you do surgeries on these areas

What three things is important to remember about the Pancreas

1) Pancreas is retroperitoneal
→ because its right in front of the vertebral column, people with the pancreas will have back pain

2) blood vessels with the pancreas are important to know in relation to cancer
→ the SMA and SMV are posterior to the neck of the pancreas, you cannot do surgery if there is cancer that involves these two vessels

3) Cancer of the pancreatic tail usually requires a splenectomy because the pancreas is located right next to the spleen
→ you would need vaccines for encapsulated bacteria prior to removal

What is the key point for the appendix?

when you have appendicitis, at the beginning you will have periumbilical pain that may later progress to lower quadrant pain
→ this is because the visceral nerves will cover the appendix which will refer pain via the thoracic splanchnic nerves, which explains the initial periumbilical pain
→ after a while, appendicitis will irritate the parietal peritoneum, leading to right lower quadrant pain from the parietal nerves