TYPES OF OSTIA NASOLACRIMALIA IN MAN AND 

 THEIR GENETIC SIGNIFICANCE 



J. PARSONS SCHAEFFER 



Yale University 

 From the Anatomical Laboratory of the Yale Medical School 



FIFTEEN FIGURES 



During a recent investigation on the genesis and development 

 of the nasolacrimal passages in man, my attention was frequently 

 directed to the marked variations that exist, in the adult, in the 

 manner of communication between the ductus nasolacrimal 

 and the meatus nasi inferior. I, therefore, wish in this note to 

 refer to the principal types of ostia nasolacrimalia found, and to 

 call attention to their probable genetic significance. 



LOCATIOX 



At the outset I may say, according to the material studied, 

 that the ostium of the ductus nasolacrimalis is invariably located 

 somewhere on the ventral portion of the lateral wall of the meatus 

 nasi inferior. The variations encountered are due to differences 

 in type, position within the above limits, and to duplication. 

 Notwithstanding that the large series of specimens examined for 

 the substance of this communication invariably presented the 

 ostium of the ductus nasolacrimalis on the lateral wall of the 

 meatus nasi inferior, Geddes 1 reports an unusual and apparently 

 unique abnormality in an Irish male subject of the age of twenty- 

 eight years, in which the ductus nasolacrimalis communicated 

 with the meatus nasi medius. I will refer to this unusual abnor- 

 mality in a subsequent paragraph. 



Within the limits of the ventral portion of the lateral wall of 

 the meatus nasi inferior there is considerable variation as to the 



1 An abnormal nasal duct. Anatom. Anz., Bd. 37, no. 1, 1910. 



183 



