Accessory fissures of the upper lobe of the left lung: CT and plain film appearance.

Abstract

Accessory fissures of the upper lobe of the left lung, as shown by CT, can separate any two contiguous segments, are frequently incomplete, and occur in four different configurations. The left minor fissure is the most common of these fissures and the most frequently seen on chest radiographs. The ability to recognize accessory fissures of the left upper lobe should help in the segmental and topographic localization of pulmonary lesions.