Variations in the Morphology of Human Lungs and its Clinical Implications

Abstract

Objective To observe variations in the fissures, in the lobes, and in the hilar pattern of lungs and correlate these findings with clinical implications. Materials and Methods The present study was performed on random lung specimens available in the Department of Anatomy. A total of 96 lungs (47 right and 49 left) were studied for variations in the fissures and lobes, and 92 lungs (45 right and 47 left) for variations in the hilar pattern. Results Among the right-sided lungs, 70% presented incomplete horizontal fissure, 15% with absence of the horizontal fissure, and 51% with incomplete oblique fissure. Accessory fissures were also seen, but incomplete, and accounted for 17% of the total number of right lungs.Among the left-sided lungs, 62% presented incomplete oblique fissures, and 4% with absence of the oblique fissure. Accessory fissures accounted for 6% of the total number of left lungs.Regarding hilar pattern variations, 11% of the right-sided lungs showed > 2 bronchi, 69% showed > 2 pulmonary veins, and 37% showed > 1 pulmonary artery.Among the left-sided lungs, 57% showed > 1 bronchi, 21% showed > 2 pulmonary veins, and 17% showed > 1 pulmonary artery. Conclusion The field of pulmonary surgery is now highly advanced, with well-developed radiological and endoscopic techniques. Hence, a proper understanding and knowledge of these morphological variations of lung fissures and of the hilar pattern would be advantageous for surgeons, as well as for radiologists.

Morphological variations of fissures, lobes, and hilar pattern of the lung in a select South African sample

“…In the present study, the usual morphology of two bronchi (eparterial and hyparterial) in the hilum of the right lung was observed in 65.9% of the specimens. This incidence is lower compared to studies by Murlimanju et al [30]; George et al [9]; Jacobs et al, [15] Unforeseen bleeding originating from the pulmonary artery may be occasionally encountered by surgeons, thus knowledge of the pulmonary artery anatomy as well as their variations is vital to avoid complications [36]. The present study observed a single pulmonary artery in 95.5% right lungs.…”

“…[6] and Jacobs et al [15] which reported 61.54% and 51% incomplete oblique ssures, respectively. Magadum et al [23] deviated from this observation by having a higher incidence of incomplete oblique ssures compared to incomplete horizontal ssures.…”

“…This variant is characterized by the partitioning of the right upper lobe due to the atypical course of the azygos vein, forming an additional lobe [26]. The prevalence of this variant lobe ranges from 0.4% to 1% in the general population [15]. Kc et al,[18] reported one case of an azygous lobe.…”

“…The lungs are divided into lobes by ssures, such as the horizontal and oblique ssures which are invaginations of visceral pleura. These ssures separate the lobes almost to the hilum, allowing for easy movement and uniform expansion of the lungs during respiration [15,16]. The right lung is divided into three lobes: the superior, middle, and inferior lobes separated by horizontal and oblique ssures [25].…”

Morphological variations of the lung: Accessory fissures and lobes

“…However, as previously reported, fissures can be categorized as complete, incomplete, absent, or additional/accessory (Berkmen et al, 1994; George et al, 2014; Heřmanová et al, 2014; Jacob et al, 2019; Mathangasinghe et al, 2021; Murlimanju et al, 2012; Sailaja, 2015). Furthermore, owing to the importance of this organ, lung variations play a pivotal role in clinical medicine.…”