pores of Kohn
The pores of Kohn (also known as interalveolar connections or alveolar pores) are discrete holes in walls of adjacent alveoli.{{cite journal| author1=Desplechain C. | author2=Foliguet B. | author3=Barrat E. | author4=Grignon G. | author5=Touati F.| title=[The pores of Kohn in pulmonary alveoli] | journal=Bull Eur Physiopathol Respir | year= 1983 | volume= 19 | issue= 1 | pages= 59–68 | pmid=6850150 }} Cuboidal type II alveolar cells, which produce surfactant, usually form part of aperture.{{cite book|last=Miller|first=J.E. Cotes, D.J. Chinn, M.R.|title=Lung function : theory and measurement in health and disease|url=https://archive.org/details/lungfunctionphys00cote|url-access=limited|year=2006|publisher=Blackwell Pub.|location=Malden, Mass.|isbn=978-0-632-06493-9|page=[https://archive.org/details/lungfunctionphys00cote/page/n35 27]|edition=6th}}
Etymology
The pores of Kohn take their name from the German physician and pathologist Hans Nathan Kohn (1866–1935) who first described them in 1893.H.N. Kohn: “Zur Histologie der indurierenden fibrinösen Pneumonie”. Münchener Medicinische Wochenschrift 1893 40: 42-45{{Cite journal|last1=Gompelmann|first1=D.|last2=Eberhardt|first2=R.|last3=Herth|first3=F.J.F.|date=2013|title=Collateral Ventilation|url=https://www.karger.com/Article/PDF/348269|journal=Respiration|language=en|volume=85|issue=6|pages=515–520|doi=10.1159/000348269|pmid=23485627|issn=0025-7931|doi-access=free}}
Development
They are absent in human newborns. They develop at 3–4 years of age along with canals of Lambert during the process of thinning of alveolar septa.{{cite book|editor-first=Jürg |editor-last=Hammer|title=Paediatric pulmonary function testing : 41 tables|url=https://archive.org/details/pediatricpulmona00hamm |url-access=limited |year=2005|publisher=Karger|location=Basel [u.a.]|isbn=3-8055-7753-2|edition=[Online-Ausg.]|pages=[https://archive.org/details/pediatricpulmona00hamm/page/n16 6]}}
Function
The pores allow the passage of other materials such as fluid and bacteria, which is an important mechanism of spread of infection in lobar pneumonia and spread of fibrin in the grey hepatisation phase of recovery from the same. They also equalize the pressure in adjacent alveoli and, combined with increased distribution of surfactant, thus play an important role in prevention of collapse of the lung.{{cite book|title=Clinical Procedures In Emergency Medicine & Color Atlas Of Emergency Department Procedures.|year=2005|publisher=W B Saunders Co|isbn=1416022503|page=149}}
Unlike adults, in children these inter-alveolar connections are poorly developed which aids in limiting the spread of infection. This is thought to contribute to round pneumonia.{{Cite web|url=https://radiopaedia.org/articles/round-pneumonia-1?lang=us|title=Round pneumonia | Radiology Reference Article | Radiopaedia.org|first=Yuranga|last=Weerakkody|website=Radiopaedia}}