THE PHARYNX. * 373 



openings of the nasal cavities ; 2, Behind, and directly opposite the pre- 

 ceding, the two pharyngeal openings of the Eustachian tubes, which are 

 closed by a cartilaginous kind of clap-valve. 1 



At the inferior extremity of this axis is found : 1, In the centre, a vast 

 gaping orifice projecting into the anterior of the pharyngeal cavity, like a tap 

 into a cask : this is the entrance to the larynx, the salient portions of which 

 form, on the walls of the pharynx, two lateral gutters limited superiorly by 

 the posterior pillars of the soft palate ; 2, In front of, and beneath this, is 

 the isthmus of the fauces ; Behind and above, the cesophageal opening at the 

 bottom of an infundibulum, which may be considered as a special region of 

 the pharynx. 



These seven openings of the pharyngeal cavity give it the appearance of 

 a cross road, into which abut different thoroughfares. It is necessary to 

 note that the air and digestive passages intersect each other here, and in 

 such a way that, during deglutition, the bolus of food passes over the entrance 

 of the larynx to reach the cesophageal opening. This peculiarity is easily 

 seen by referring to figure 175. 



Fig. 175. 



2t 



MEDIAN LONGITUDINAL SECTION OF HEAD AND UPPER PART OF NECK. 



1, Upper lip ; 2, Premaxilla ; 3, Hard palate ; 4, Tongue ; 5, Septum nasi ; 6, Nasal 

 bone; 7, Palate bone; 8, Soft palate; 9, Pterygoid bone; 10, Epiglottis; 11, 

 Entrance to Eustachian tube; 12, Arytenoid cartilage; 13, Cricoid cartilage; 

 14, (Esophagus ; 15, Frontal bone and sinus ; 16, Cerebrum ; 17, Corpus cal- 

 losum ; 18, Cerebellum ; 19, Sphenoid bone ; 20, Medulla oblongata ; 21, Cervical 

 ligament ; 22, Spinal cord ; 23, Occipital boue ; 24, 24, Atlas ; 25, 25, Dentata ; 

 26, Trachea. 



Relations. Viewed externally, for the study of its connections, it will be 

 found that the pharynx responds, posteriorly, to the guttural pouches and 

 guttural lymphatics ; laterally, to the large branch of the os hyoides, the 



1 This region corresponds to the posterior nares (arriere fond) of Man, a diverticulum 

 which cannot be distinguished from the pharynx in the domesticated animals. Under 

 the designation of the posterior nares of the nasal fossx, it will be understood that we 

 mean the posterior extremities of these cavities. 



(In the 'Annales de Medecine Veterinaire? of Brussels, for 1871 (p. 244), M. Lorge 

 describes a pharyngeal caecum as existing in Solipeds, which he states corresponds to the 

 naso-pharyngeal region, or posterior nares, of Man.) 

 27 



