Are textbook lungs really normal? A cadaveric study on the anatomical and clinical importance of variations in the major lung fissures, and the incomplete right horizontal fissure

Abstract

Introduction The lungs have three main fissures: the right oblique fissure (ROF), right horizontal fissure (RHF), and left oblique fissure (LOF). These can be complete, incomplete or absent; quantifying the degree of completeness of these fissures is novel. Standard textbooks often refer to the fissures as complete, but awareness of variation is essential in thoracic surgery. Materials and Methods Fissures in 81 pairs of cadaveric lungs were classified. Oblique fissures were measured from lung hila posteriorly to the lung hila anteriorly; and the RHF measured from the ROF to the anteromedial lung edge. The degree of completeness of fissures was expressed as a percentage of the total projected length were they to be complete. The frequency and location of accessory fissures was noted. Results LOF were complete in 66/81 (81.5%), incomplete in 13/81 (16.0%) and absent in 2/81 (2.47%); ROF were complete in 52/81 (64.2%), incomplete in 29/81 (35.8%) and never absent; RHF were more variable, complete in 18/81 (22.2%), incomplete in 54/81 (66.7%) and absent in 9/81 (11.1%). LOF and ROF were on average 97.1% and 91.6% complete, respectively, being deficient posteriorly at the lung hila. The RHF on average 69.4% complete, being deficient anteromedially. There were accessory fissures in 10 left and 19 right lungs. Conclusions This study provides a projection of the anatomy thoracic surgeons may encounter at operation, in particular the variable RHF. This knowledge is essential for optimal outcomes in both benign and oncological procedures influenced by the fissures.

Morphological variations of lung lobes and fissures: a preliminary study

“…This finding is consistent with the majority of previous reports, where oblique fissure was consistently noted, with at least 50% of the oblique fissures being complete [see Supplementary Table 2]. However, incompleteness of the The Sri Lanka Journal of Surgery 2021; 39(3): 24-27 oblique fissure was more commonly noted anteriorly [1,5] in contrast to our finding where it was deficient posteriorly. The frequency of absent horizontal fissure was on par with the previous reports.…”

“…Knowledge of the anatomical variations of the lungs is important for the radiologists to interpret radiographs, for the thoracic surgeons to plan segmental resections/lobectomies and for the bronchoscopists in minimally invasive endoscopic procedures. The reported prevalence of morphological variations of the lung lobes and fissures vary widely in different populations [1]. Despite these variants being well reported in the literature, to our knowledge, there are no publications about a Sri Lankan population.…”

“…The right oblique fissure separates the right middle lobe from the right lower lobe while the horizontal fissure separates the right upper lobe from the right middle lobe. However, the separation of these lobes by the said fissures is often incomplete in contrast to the textbook descriptions [1]. Moreover, accessory fissures are formed due to the anomalous development of the lung.…”

Microscopic anatomical, immunohistochemical, and morphometric characterization of the terminal airways of the lung in cetaceans

“…However, proper inflation of organs as large as those of baleen whales and the larger toothed cetaceans is rather difficult to perform optimally at the stranding site, where most of the tissue samples (or whole organs) were removed from the carcass. The key issue of what constitutes a normal lung has also been recently thoroughly discussed in relation to the anatomy of the human lungs (West et al, 2020). To this effect, we are aware that our study considers a limited number of specimens, something that cannot be avoided considering the rarity of stranding events for some species and the difficulties inherent to their body size and pathology present that contributed to their stranding.…”

Lung Fissural Integrity: It’s Written in the Genes

“…There is no mainstream remedy at present. Differences in fissural integrity have been appreciated since 1947 ( 13) and a number of cadaveric studies in diverse populations, despite the potential confounding effects of methodological heterogeneities, have suggested a possible link to ethnicity (14). However, the determinants and natural course of fissural integrity are unclear.…”