396 



HEAD AND NECK 



It is slightly hollowed out and concave, and at its upper part, 

 near the nasal bone, a feeble elevation termed the agger nasi 

 may be noticed ; this begins close to the anterior part of the 

 attached margin of the middle concha, and runs obliquely 



FIG. 155. 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. Vibrissse. 



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. 



n. Recessus spheno-ethmoidalis. 



12. Superior concha. 



13. Superior meatus. 



14. Middle concha. 



15. Inferior concha. 



16. Plica naso-pharyngea. 



17. Meatus naso-pharyngeus. 



18. Orifice of auditory tube. 



19. Posterior lip of auditory tube. 



20. Lateral recess of pharynx. 



21. Incisive foramen. 



a, b, c. Free border of the middle concha. 



downwards and anteriorly. It represents an additional concha 

 which is present in some mammals. A slight depression 

 above the agger nasi, which leads posteriorly to the olfactory 

 district of the lateral wall of the nasal cavity, is the sulcus 

 olfactorius. 



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



