Appendix is a tube-shaped organ with a length of approximately 10 cm and the stem on the caecum. Appendix has a narrow lumen at proximal and wide in the distal. At birth, appendix was short. When the child, the growth is usually rotated into the retrocaecal but still in intraperitoneal. Appendix has three tanea coli that fused in the caecum and could be useful in indicating where to detect the appendix. The position of the appendix is the most Retrocaecal (74%) and then following the Pelvic (21%), Patileal (5%), Paracaecal (2%), subcaecal (1.5%) and preleal (1%).

Appendix is blooded by apendicular artery which is a branch of the artery ileocolica. Arterial appendix is end arteries. Appendix has more than 6 mesoapendiks obstruct lymph channels leading to lymph nodes ileocaecal. Although the appendix has less functionality, but the appendix can function like any other organ. Appendix produces mucus 1-2ml per day.

The mucus poured into the caecum. If there is resistance there will be a pathogenesis of acute appendicitis. GALT (Gut  Assoiated  Lymphoid  Tissue) in the appendix produce Ig-A.  However, if the appendix removed, none affect the  immune body system.