THE HEAD AND NECK 



1255 



are concealed by the middle concha. When this is removed the 

 lateral wall of the middle meatus is seen to present a deep curved 

 groove, called the hiatus semilunaris, which is directed downwards 

 and backwards from the lower end of the infundibulum. Behind 

 and above this hiatus there is a round prominence, called the 

 bulla ethmoidalis. The opening of the anterior ethmoidal cells is 

 situated in the vertical portion of the hiatus semilunaris, and the 

 opening of the antrum of Highmore, which is of small size, is placed 



FroQtal Air-Sinus 



Snperio: Meatus 



\ Superior Concha 

 \ / Spheno-ethmoidal Recess 



Inferior Meatus 

 Hard Palate (in section) 

 Tongue 



Mandib!s (in section) 



^.- Sphenoidal Air-Sintl3 

 Middle Concha 



..Middle Meatus 



..Inferior Concha 



Eustachian Orifice 



Salpingo-pharyngeal 

 Fold 



..Soft Palate 



"- Epiglottis 

 Pharynx 



Gcnio-fayo-glossus 



Genio-hjrpid 



Vrntricle of Larynx y 

 Thyroid Cartilage 

 Cricoid Cartilage 



(Esophagus 



Tracb:= 



Fig. 513. — Sagittal Section through the Nasal Fossa, Mouth, 

 Pharynx, (Esophagus, and Larynx. 



(The Outer Wall of the Right Nasal Fossa is shown). 



in its hori2ontal portion, whilst the middle ethmoidal cells open 

 above the bulla ethmoidalis. In front of the middle meatus is the 

 region known as the atrium, which communicates anteriorly with 

 the vestibule, the latter being situated just within the ala of the 

 nostril. 



The inferior meatus is situated below the inferior concha. Open- 

 ing into its anterior part, under cover of the inferior concha, 

 is the lower orifice of the nasal duct, which is provided with an 

 imperfect mucous fold, called the valve of Hasner. The orifice is 

 about i^ inches from the anterior nasal aperture. 



