Appendicitis, an inflammation of the vestigial vermiform appendix, is one of the most common causes of the acute abdomen and one of the most frequent indications for an emergent abdominal surgical procedure worldwide [1,2].
The clinical manifestations and diagnosis of appendicitis in adults will be reviewed here. The management of appendicitis in adults and appendicitis in pregnancy and children are discussed separately. (See "Management of acute appendicitis in adults" and "Acute appendicitis in pregnancy" and "Acute appendicitis in children: Clinical manifestations and diagnosis".)
The vermiform appendix is located at the base of the cecum, near the ileocecal valve where the taenia coli converge on the cecum (figure 1) [3,4]. The appendix is a true diverticulum of the cecum. In contrast to acquired diverticular disease, which consists of a protuberance of a subset of the enteric wall layers, the appendiceal wall contains all of the layers of the colonic wall: mucosa, submucosa, muscularis (longitudinal and circular), and the serosal covering .
The appendiceal orifice opens into the cecum. Its blood supply, the appendiceal artery, is a terminal branch of the ileocolic artery, which traverses the length of the mesoappendix and terminates at the tip of the organ (figure 2) .
The attachment of the appendix to the base of the cecum is constant. However, the tip may migrate to the retrocecal, subcecal, preileal, postileal, and pelvic positions. These normal anatomic variations can complicate the diagnosis as the site of pain and findings on the clinical examination will reflect the anatomic position of the appendix.