THE DEVELOPMENT AND ANATOMY OF THE 

 NASAL ACCESSORY SINUSES IN MAN 



ANATOMIC MATERIAL USED 



The anatomic material upon which the observations given 

 in this report are based consists of the following specimens : 



(a) Serial sections for microscopic study of the nasal 

 areas of 14 embryos and fetuses, the ages of which were 

 reckoned as closely as possible by estimates based upon the 

 measurements of total length (Diihrssen's method), and also 

 upon length from vertex to buttocks. The ages expressed 

 in days of embryonal life were as follows: 60, 63, 65, 85, 

 91, 95, 98, 100, 115, 117, 118, 121, 126, and 133 days. 



(6) Sagittal and coronal sections for macroscopic study 

 of the heads of 8 fetuses, aged respectively 137, 139, 151, 188, 

 196, 202, 224, and 246 days. 



(c) Sagittal and horizontal sections of the heads of 4 

 full-term fetuses. 



(d) Sagittal, coronal, and horizontal sections of the nasal 

 and accessory sinus areas of 101 postnatal heads, the mucosa 

 remaining intact in each case. The exact ages of cases from 

 which specimens were obtained are given in the following 

 table: 



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