Lobes and fissures in fetal lung at different gestational ages: anatomical study with clinical significance

Objectives: lungs are divided into various lobes by oblique and horizontal fissures. The fissures can be complete, incomplete or accessory depending on the partial obliteration or due to the non-fusion of spaces between the bronchopulmonary buds. The fissures help in the movement of lobes in relation to one otherresulting in greater distention and movements of lower lobes during respiration. The knowledge of fissures and lobes of the lungs are important to plan various surgical procedures.
Background: The current research paper helps us to know the earliest appearance of fissures, as the study was done on the fetal lung of varying gestational ages, earliest being 10 weeks of gestation. The partial or complete obliteration of prenatal fissures results in absence or incompleteness of fissure. Any variation in morphological pattern of fissures indicates variations from normal pattern of development of lung. The knowledge of the fissures and lobes are important to plan various surgical procedures and also to avoid post-operative complications like air leakage. Various radiological appearances of lobar anatomy of lungs and the position of the interlobar fluid helps the cardiothoracic surgeons during surgical resection of individual lung segments. Post-operative air leakage is most commonly due to an incomplete fissure and accessory fissure, might act as a barrier to spread in the tissue creating a sharply demarcated pneumonia, which could be misinterpreted in the radiograph as atelectasis or consolidation.
Results: Variation in the appearance of lobes and fissures were noted. There was absence and incomplete horizontal fissure in the right lung. 23 cases presented with complete fissure and 14 fetuses presented with incomplete horizontal fissure. In the left lung complete oblique fissure was observed in 38 specimens and 2 specimens presented with incomplete oblique fissure.
Conclusion: Study of lobes and fissures is important to know the anatomical variations in the lobulation of lungs during segmental or lobar resections of lungs. There can be misinterpretation of accessory lobes and fissures on X-rays and CT scans.