Organ
Vermiform appendix
A lymphoid-rich blind extension of the cecum
High-yield
The base has a consistent relationship to the cecal taeniae, but neither base nor tip is guaranteed to lie beneath McBurney's point.
Overview
The appendix is a slender diverticulum opening from the cecum near the ileocecal junction. Its mesoappendix carries the vascular supply. Length and tip position vary substantially, while convergence of the cecal taeniae identifies its base.
Reference facts
- Location
- Usually arises from the posteromedial cecum in the right lower abdomen; a mobile or malpositioned cecum changes that location.
- Parts
- Base, tubular body and blind tip, with a mesoappendix connecting it to the ileocecal mesenteric region.
- Blood supply
- Usually an appendicular branch of the ileocolic system; accessory arterial contributions occur, so a single end-artery pattern is not universal.
- Innervation
- Autonomic fibers arrive through the superior mesenteric plexus; pain afferents commonly reach the cord around T10.
- Venous/Lymphatic drainage
- Appendicular veins join ileocolic tributaries; lymph passes to regional ileocolic nodes.
- Relations
- Tip positions include retrocecal, pelvic, subcecal, paracecal and locations anterior or posterior to terminal ileum.
- Function
- Gut-associated lymphoid tissue contributes to mucosal immunity; the appendix is not required for normal digestion.
Clinical correlation
Inflammation may first cause poorly localized periumbilical pain and later localized pain when adjacent parietal peritoneum becomes involved. Venous congestion and impaired arterial perfusion can lead to necrosis. Retrocecal and pelvic positions alter symptoms and examination findings.
Frequently asked questions
Where is the vermiform appendix located?
Usually arises from the posteromedial cecum in the right lower abdomen; a mobile or malpositioned cecum changes that location.
What does the vermiform appendix do?
Gut-associated lymphoid tissue contributes to mucosal immunity; the appendix is not required for normal digestion.
What are the parts of the vermiform appendix?
The parts of the vermiform appendix are the base, tubular body and blind tip, with a mesoappendix connecting it to the ileocecal mesenteric region.
What is the blood supply of the vermiform appendix?
Usually an appendicular branch of the ileocolic system; accessory arterial contributions occur, so a single end-artery pattern is not universal.