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Appendix (wormhole).
Last reviewed: 04.07.2025
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The vermiform appendix, which is an important organ of the immune system, is anatomically and topographically connected to the cecum.
The appendix (appendix vermiformis) originates from the posteromedial surface of the cecum, its length varies widely - from 2 to 24 cm (on average 9 cm); its diameter is 0.5-1.0 cm. The vermiform appendix can have a variety of directions. Usually, the appendix is located in the right iliac fossa, but can descend into the pelvic cavity. The direction of the appendix can be descending (40-45%), lateral (17-20%) or ascending (13%). With an ascending direction, the appendix is often located behind the cecum (retrocecal position) or even retroperitoneally. Usually, the appendix has a mesentery connecting it to the wall of the cecum and the terminal section of the ileum.
From a practical point of view, it is very important to know the projection of the base (beginning) of the vermiform appendix onto the anterior abdominal wall. The base of the vermiform appendix is projected onto the anterior abdominal wall at the border between the outer and middle thirds of the line connecting the right upper anterior iliac spine and the umbilicus (McBurney's point).
However, such a position of the vermiform appendix is rare. Most often, the base of the vermiform appendix is projected on the border between the outer and middle thirds of the line connecting the right and left superior anterior iliac spines (Lantz's point).