The normal vermiform appendixin adults: its anatomical location, visualization, and diameter at computed tomography

Introduction: The anatomic location of the appendiceal tip is not certain and it may extend to the retrocecal, pelvic, subcecal, paracecal, postileal, or preileal positions. Its positional variations may alter the degree of inflammation and lead to further illness diagnoses such as colitis, ureteric colic, or pelvic inflammatory disease. Increase in appendiceal diameter is very important regarding the diagnosis of appendicitis. Therefore, the determination of cut-off values for normal appendiceal diameter in computed tomography (CT) would aid in ruling out appendicitis in suspected cases. We aimed in this study to evaluate the frequency of visualization and determine the location and diameter of the normal appendix on CT. Material and Methods: We scanned 1842 abdominal CT that were performed in our hospital for any reason, retrospectively. A total of 597 patients were excluded with various indications. Results: Lower-upper abdominal CT examinations of a total of 1245 patients were evaluated, and the appendix could be visualized in 984 patients (79%). The appendiceal diameter was ranged between 2.7 mm and 10 mm and it was >6 mm in 19% of the patients. The most common location of the appendiceal tip was pelvic in 318 (32%) appendices. The appendiceal tip was subcecal in 222 (23%), retrocecal in 180 (18%), postileal in 180 (18%), preileal in 54 (6%), and paracaecal in 30 (3%) appendices. Discussion and Conclusion: This study showed that the most frequent location of the normal appendix is pelvic type both in women and men.