156 



THE HEAD AND NECK 



epiglottic fold. These depressions the valleculce are bounded 

 behind by transverse ridges, which extend from the side of the 

 epiglottis to the lateral walls of the pharynx. The floor of the 

 vallecula lies immediately above and behind the hyoid bone 



(Fig. 50)- 



Over the free upper border of the epiglottis the mucous 

 membrane of the mouth becomes continuous with that of the 



Tongue 



Hyoid 

 Plica vocalis 



Rima glottidi 



Recessus piriformis 



Superior cornu 

 of thyreoid 



Pharyngeal wall 

 (cut) 



Glosso-epiglottic 

 fold 



Vallecula 



Pharyngo- 

 epiglottic fold 



r Epiglottis 



Tubercle of 

 epiglottis 



Ary-epiglottic 



fold 



Laryngeal ventricle 



Plica ventricularis 

 Cuneiform cartilage 



Corniculate 

 'cartilage 



Mucous membrane 

 covering posterior 

 aspect of cricoid 

 cartilage 



FIG. 48. Upper Aperture of the Larynx, exposed by cutting through 

 the posterior wall of the pharynx. 



larynx. A fold of mucous membrane stretches from each side 

 of the epiglottis downwards, backwards, and medially to the 

 apex of the arytenoid cartilage (ary-epiglottic folds). These 

 folds, together with the epiglottis, form the boundaries of the 

 upper opening into the larynx, and owing to the obliquity of its 

 lateral margins, the plane of the opening looks almost directly 

 backwards. Between the ary-epiglottic fold and the pharyngo- 

 epiglottic fold the mucous membrane lines a small depression 

 the recessus piriformis which lies in close relation to the deep 

 surface of the thyreo-hyoid membrane. This area is supplied 



