Appendix

Structure

The appendix is typically 5 to 10 centimeters long and about 1 centimeter wide, although length and position vary considerably. It branches from the posteromedial wall of the cecum a few centimeters below the ileocecal valve.

Lining

Its wall contains a high concentration of lymphoid follicles, especially in childhood, making it part of the gut-associated lymphatic tissue that monitors and responds to intestinal antigens.

Function

The appendix has long been considered a vestigial structure. Current thinking suggests it acts as a refuge for normal gut microbiota, helping repopulate the colon after disturbances such as severe diarrhea.