Incomplete Oblique Fissure, Absence of Horizontal Fissure: A Case Report

Abstract

The right Lung classically has one oblique fissure and one horizontal fissure and Three Lobes namely Upper, Lower, and middle Lobes. Variations in the lung fissures and lobes have been described by many authors which have got their Surgical and Radiological importance. During Routine dissection in the Department of Anatomy, S.V. Medical College, Tirupati, we encountered an Incomplete oblique Fissure, Absence of Horizontal fissure in the Right Lung of an Adult male Cadaver. Anatomical Knowledge of the variations of Fissures of Lung are important for C.T. Surgeons performing Lobectomies, and Radiologists I. Introduction Right lung is broader and heavier than the left lung. Two fissures oblique and horizontal , divide it into three lobes namely, upper, middle and lower. The oblique fissure separates the lower lobe from the remaining two lobes. It runs obliquely and crosses the inferior border of the lung about 7.5 cm behind its anterior end. The horizontal fissure separates the upper and middle lobe. It begins from the oblique fissure, runs horizontally and cuts the anterior border at inner end of fourth costal cartilage. The longer and lighter left lung is divided into a superior and an inferior lobe by an oblique fissure which extends from costal to medial .surfaces of the lung both above and below the hilum 3 The fissures facilitate the movement of the lobes in relation to one another, which accommodates greater distention and movement of the lobes during respiration. The fissures may be complete, incomplete or absent. In case of complete fissure the lung lobes are held together only at the hilum by the bronchi and the pulmonary vessels. Parenchymal fusion of varied extent along the floor is found in case of incomplete fissure 4 . Knowledge of the anatomy and variations of the major fissures are essential for recognizing their variable imaging appearances as well as related abnormalities. The cardiothoracic surgeons performing segmental lung resections and the radiologists must have a detailed knowledge of variations of classical and accessory fissures regarding their length, depth, positions etc to have uncomplicated peroperative and postoperative events and proper radiological interpretations respectively.