NASAL CAVITIES 



may be noticed ; the agger nasi begins close to the anterior 

 part of the attached margin of the middle concha, and runs 

 obliquely downwards and forwards. It represents an addi- 

 tional concha which is present in some mammals. A slight 

 depression above the agger nasi, which leads posteriorly to 



FIG. 116. Lateral wall of the Left Nasal Cavity. (From Schwalbe. 



1. Frontal air sinus. 



2. Free border of the nasal bone. 



3. Cribriform plate of ethmoid. 



4. Sphenoidal air sinus, 



5. Vibrissae. 



6', 6. The two parts of the vestibular area. 



7. Elevation intervening between the 



vestibular district and the atrium. 



8. Atrium meatus medii. 



9. Agger nasi, or rudiment of an anterior 



concha. 

 10. Concha suprema. 



ir. Recessus spheno-ethmoidalis. 



12. Superior concha. 



13. Superior meatus. 



14. Middle concha. 



15. Inferior concha. 



1 6. Plica naso-pharyngea. 



17. Meatus naso-pharyngeus. 



1 8. Orifice of auditory tube. 



19. Posterior lip of auditory tube. 



20. Pharyngeal recess. 



21. Incisive foramen. 



, l>, c. Free border of the middle concha. 



the olfactory district of the lateral wall of the nasal cavity, 

 is the sulcus olfadorius. 



Conchae (O.T. turbinal bones). Posterior to the vestibule 

 and the atrium are the conchae, with the intervening meatuses. 

 The superior concha (Fig. 116, 12), which projects from the 

 labyrinth of the ethmoid bone, is very short, and is placed 



