ANATOMY OF THE OLFACTORY ORGAN 



25 



the lateral wall of each nasal chamber into its cavity and 

 partly divide that cavity into three approximately hori- 

 zontal passages: the inferior meatus under the inferior 

 concha, the middle meatus under the middle concha and 

 the superior meatus under the superior concha. (Fig. 2). 

 The external naris leads at once 

 to the first chamber of the nose, 

 the vestibule, which connects 

 almost directly with the inferior 

 meatus, less directly with the su- 

 perior meatus and through the 

 so-called atrium with the middle 

 meatus. Between the median sep- 

 tum of the nose and the laterally 

 situated conchas is a considerable 

 space known as the common 

 meatus. Dorsally this space is 

 continuous with a narrow slit 

 lying between the superior concha 

 and the septum and called the 

 olfactory cleft. Air these pas- 

 sages and spaces communicate 

 more or less directly and freely 

 through the posterior naris or 

 choana with the pharynx. 



In the bones about the nose in man are large paired air- 

 spaces or sinuses that communicate with the exterior 

 through the nasal cavity. These spaces, which have been 

 very fully described by Schaeffer (1916), are of consid- 

 erable size and are lined with a mucous epithelium con- 

 tinuous with that of the nose. They are somewhat variable 

 in number and connections and yet they fall more or less 



Fio. 2. Diagram of a trans- 

 verse section of the right nasal 

 cavity in man made at the plane 

 indicated by the vertical dotted 

 line in Fig. 1. 1, inferior concha; 

 2, middle concha ; 3, superior con- 

 cha; 4, nasal septum; 5, inferior 

 meatus; 6, middle meatus; 7, 

 superior meatus; 8, common 

 meatus; 9, olfactory cleft (left 

 side); 10, ethmoid cells; 11, 

 maxillary sinus. 



