Incomplete and accessory pulmonary fissures. A study by high resolution CT scan imaging

High resolution CT examinations with 1.5 mm thick slices were performed on 30 healthy volunteers for the study of normal and accessory pulmonary fissures. In only one case were the three fissures entirely present. The major fissure is incomplete in 87% of the cases on the right side, and in 77% on the left side. When a part of a fissure is absent it is always the internal part. One or more accessory fissures were seen in 59% of the cases. The most frequent accessory fissures are in the inferior lobes (33%). A left minor fissure was seen in 10% of the cases. Some aspects of the top of the minor fissures (opacity, false cavitary lesion) which can be misinterpreted are emphasized