Dr. Alwan, Amir(Assistant professor of radiology, Department of Radiology, AAU-CHS)Dr.Gissila, Azmera(Assistant professor of radiology, Department of Radiology, AAU-CHS)Abera, Mebratu2021-03-142023-11-052021-03-142023-11-052020-11http://etd.aau.edu.et/handle/123456789/25470Objective: To determine morphological variations of major and minor fissures, to assess frequency of accessory fissures as well as incomplete major and minor fissures in patients attending at Tikur Anbesa Specialized Hospital, Addis Ababa. Methods: This is an institutional based cross sectional prospective observational study where a total of 1020 patients whose Chest CT images have no lung pathology included in the study group for evaluation. Then an assessment of the chest CT images on multiplanar reconstructions done to determine frequency of accessory fissures and incomplete major and minor fissures in both lungs. Results: Out of 1020 patients who have no any lung abnormality on CT images selected within the study period 2% of them have absent right minor fissure making bilobed right lung. The most common accessory fissure in the right lung was inferior accessory fissure comprising 10% of the study group. Azygos fissure happened to occur in 12 patients (1.2%) of the sample under study. On the left lung the most common accessory fissure was the left minor fissure which accounted for 3.5% of the included study group making trilobed left lung. The major fissures on both sides have significant amount of incompleteness making 45% and 32% on the right and left sides respectively. Classic three right and two left lung lobes with complete major and minor fissures and no accessory fissure is found in only 418 subjects (41%). Conclusion: Variations of lung fissures assessed based on chest CT with multiplanar reconstructions showed no significant deviation from other studies done on large sample size. The degree of incompleteness of the fissures and percentage of accessory fissures are more common on the right lung than the left lung. The uppermost extent of the left major fissure was always higher than the right lung major fissure invariably.en-USFissures,patients, LungThesis