Editing Lung (section)

=== Variation ===
The lobes of the lung are subject to [[anatomical variation]]s.<ref name="Moore2">{{cite book |last1=Moore |first1=K |title=Clinically oriented anatomy |date=2018 |isbn=9781496347213 |page=342 |publisher=Wolters Kluwer |edition=8th}}</ref> A horizontal interlobar fissure was found to be incomplete in 25% of right lungs, or even absent in 11% of all cases. An accessory fissure was also found in 14% and 22% of left and right lungs, respectively.<ref>{{Cite journal|date=2019-06-09|title=Variations in the lobes and fissures of lungs – a study in South Indian lung specimens|url=http://www.eurjanat.com/web/paper.php?id=120051lq|journal=European Journal of Anatomy|language=en|volume=18|issue=1|pages=16–20|issn=1136-4890}}</ref> An oblique fissure was found to be incomplete in 21% to 47% of left lungs.<ref>{{cite journal |last1=Meenakshi |first1=S |last2=Manjunath |first2=KY |last3=Balasubramanyam |first3=V |title=Morphological variations of the lung fissures and lobes. |journal=The Indian Journal of Chest Diseases & Allied Sciences |date=2004 |volume=46 |issue=3 |pages=179–82 |pmid=15553206 }}</ref> In some cases a fissure is absent, or extra, resulting in a right lung with only two lobes, or a left lung with three lobes.<ref name="Moore2"/>

A variation in the airway branching structure has been found specifically in the central airway
branching. This variation is associated with the development of [[COPD]] in adulthood.<ref>{{Cite journal|title=Human lung development:recent progress and new challenges|last=Marko|first=Z|journal=Development|volume=145|issue=16|pages=dev163485|doi=10.1242/dev.163485|pmid=30111617|pmc=6124546|year=2018}}</ref>