THE GENESIS AND DEVELOPMENT OF THE 

 NASOLACRIMAL PASSAGES IN MAN 



J. PARSONS SCHAEFFER 



Yale University 

 From the Anatomical Laboratories of Cornell and Yale 



THIRTY-ONE FIGURES 



A brief review of the literature on the nasolacrimal passages 

 [lacrimal ducts (lachrymal canaliculi), lacrimal sac, nasolacrimal 

 duct] shows that diverse views were from time to time advanced 

 on the genesis and development of these passages. Before con- 

 sidering the material studied in this investigation I want to refer 

 to some of the theories held by earlier writers. I do not wish to 

 give a complete resume on the history of the development, but 

 rather in a brief manner indicate the evolution in our knowledge 

 concerning the genesis and development of these passages. 



v. Baer ('28-'37) thought that the nasolacrimal passages had 

 their origin in a diverticulum from the ' Rachenhohle.' His theory 1 

 presumably was based upon hypothetical conclusions, since it is 

 entirely unsupported. 



Burdach ('37) in his 'Die Physiologie als Erfahrungswissen- 

 schaft' writes briefly concerning the genesis of the nasolacrimal 



1 Die Bildung des Thranenkanals (in birds) glaubte ich in einer Ausstiilpung 

 der Rachenhohle, die zuerst nur wenig vor der Eustachischen Rohre liegt und 

 sehr bald nach dieser sichtbar wird, zu erkennen, doch habe ich bisher noch nicht 

 den gesammten Vorgang verfolgt. Uber Entwiekelungsgeschichte der Thiere, 

 Thiel 2, S. 116. 



Der Thriinengang stulpt sich auch hier (in mammals) aus der Rachenhohle 

 gegen das Auge hervor und liegt Anfangs hinter den Muscheln, die nur, indem sie 

 sich verlangern, sich uber ihn ziehen. tlber Entwiekelungsgeschichte der Thiere, 

 Thiel 2, S. 219. 



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THE AMERICAN JOURNAL OF ANATOMY, VOL. 13, NO. 1 

 MARCH, 1912 



