- a narrow, worm-like diverticulum arising from the caecum, inferior to the ileocaecal valve
- Its length ranges from about 5-15 cms and it is completely covered by peritoneum
- possesses a short mesentery, the mesoappendix
- Although the origin of the appendix is relatively constant, the position of its body is variable
- Most commonly, it is retrocaecal but it might also be found extending down into the pelvis, or in front of or behind the ileum
- The muscosa of the appendix is particularly rich in lymphoid tissue and it is susceptible to infection
- McBurney's point is an important surface landmark for the appendix
- It is at the junction of the lateral 1/3 and the medial 2/3 of a line joining the right anterior superior iliac spine to the umbilicus.