Abstract

Background: Pulmonary fissures are invaginations of the visceral pleura that extend from the outer surface of the lung into its substance. The fissures are grouped into normal and accessory fissures . The oblique fissure and horizontal fissures are the normal pulmonary fissures which may be complete, incomplete or absent. Incomplete pulmonary fissures are considered to be markers of collateral ventilation. They play a significant role in determining clinical response following valve replacement surgery in emphysematous patients. The Accessory fissures occurring within an individual lobe may be confused with other lesions such as linear atelectasis, pleural scar. Knowledge of the variations in the pulmonary fissures is useful for clinical interpretation. It is in this regards that this study was undertaken to assess the morphology of pulmonary fissures. Materials and methods: The study was conducted on 60 formalin preserved adult human lungs (32 right, 28 left) of unknown age and sex obtained during dissection of embalmed cadavers for undergraduate teaching in Department of Anatomy, Rajarajeswari medical college and hospital. The anatomical classification proposed by Craig and Walker is followed to determine the completeness of pulmonary fissures . Four grades of fissures have been described. Grade 1- complete fissure with entirely separate lobes. Grade 2- complete visceral cleft but parenchymal fusion at the base of the fissure. Grade 3 - visceral cleft evident for a part of the fissure. Grade 4 - complete fusion of lobes with no evident fissure line. The data was tabulated and analysed using descriptive statistics. The study was undertaken after obtaining approval from the institutional ethics committee. Results: Oblique fissure was incomplete in 13.33% of the right lungs while horizontal fissure was found to be incomplete in 30% of the right lungs. Horizontal fissure was found to be absent in 2 (3.33%) of the right lungs. A superior accessory fissure in the lower lobe separating the upper part of the lobe from the rest of the basal segments was found in one right lung . Conclusions: The present study shows that the horizontal fissure is more frequently incomplete or absent when compared to the oblique fissure in the right lung. Superior accessory fissure in the lower lobe of a right lung was observed in 1 (1.66%) specimen. Knowledge of the varying degrees of completeness of pulmonary fissures and accessory fissures is essential to avoid misinterpretation of radiological signs.

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