Ectopic acute appendicitis

At the sixth week of the embryo, a cone-shaped cecum appeared at the mesangial border of the distal branch of the midgut, which is the primordium of the cecum and appendix. The tip of the blind capsule gradually grows into an appendix. At tenth week, the midgut in the umbilical cord returns to the abdominal cavity and begins to rotate counterclockwise. At birth, a total of 270 degrees of rotation; the original lower left cecum and appendix rotate to the right palate. If the midgut does not rotate or is incomplete, the cecum and appendix are located in the left lower abdomen in situ or somewhere on the way to transposition, forming an ectopic appendix. Another reason for ectopic appendix is ​​the incomplete fixation of the midgut and the cecum and appendix in a free state. There are the following types of ectopic appendix: ① non-translocation malformation: the small intestine is on the right side, the colon is on the left side, the cecum and appendix are ectopic in the left lower abdomen; ② incomplete rotation: the cecum and appendix are located somewhere on the way of rotation For example, the left upper abdomen or subhepatic, the latter is also called the high appendix; ③ ascending colon insufficiency: blindness, ascending colon insufficiency caused changes in the position of the appendix; ④ reverse inversion: extremely rare The midgut rotates clockwise so that the small intestine is on the left and the ascending colon is on the right. In a few cases, the cecum and appendix are in the middle. Another situation can be seen in the appendix ectopic, that is the appendix is ​​located outside the peritoneum behind the cecum, which is caused by the appendix turning to the extraperitoneum behind the cecum during the decline of the cecum elongation.