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.

Charles T West,Alexander Chowdhury,Naim Slim,Cecilia Brassett,Duncan Steele

doi:10.1002/ca.23661

Abstract

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. 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. 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. 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.

Highlights

The lungs have three main fissures: the right oblique fissure (ROF), right horizontal fissure (RHF), and left oblique fissure (LOF)
This study provides a projection of the anatomy thoracic surgeons may encounter at operation, in particular the variable RHF
In anatomy textbooks, the lungs are typically described as being divided into lobes by three main fissures

Summary

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. The lungs are typically described as being divided into lobes by three main fissures. The right lung is divided into upper, middle and lower lobes by the oblique (ROF) and horizontal (RHF) fissures, while the upper and lower lobes of the left lung are separated by the oblique fissure (LOF). Variations in the fissures have been recognised since 1947 when a large autopsy study on 1,200 subjects demonstrated both incomplete and absent main fissures (Medlar, 1947). More recently a large number of cadaveric studies have been performed to ev characterise these variations in more detail, with a large number from India in particular iew (Lukose et al, 1999; Meenakshi et al, 2004; Prakash et al, 2010; Devi et al, 2011; Nene et al, 2011; Murlimanju et al, 2012; Dutta et al, 2013; Ghosh et al, 2013; Kommuru et al, 2013; Jacob and Pillay, 2013; Hema, 2014; Kaul et al, 2014; Quadros et al, 2014; Varalakshmi et al, 2014; Zareena, 2014; Divya et al, 2015; George et al., 2015; Magadum et al, 2015; Radha and Durai Pandian, 2015; Wahane and Satpute, 2015; Anbusudar and Dhivya, 2016; Dhanalakshmi et al, 2016; Mamatha et al, 2016)

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