DIGESTIVE APPARATUS. 145 



es- 



At the same time the pharynx is slightly raised and the pres 

 sure exerted on the epiglottis by the base of the tongue, 

 which projects backward, closes the larynx and allows the 

 food to glide over it. The nasal openings leading into the 

 pharynx are closed during this act by a raising of the soft 

 palate and a coming together of the borders of the posterior 

 pillars of the fauces brought about by contraction of the 

 muscles of the pharynx. 



A disturbance of normal deglutition 

 is most frequently caused by inflammatory processes in the 

 pharynx that cause infiltration and disturb the function of 

 the local muscles. The result is not only a painful condition 

 during swallowing but the closure of the larynx or nasal 

 cavities may be incomplete. Accordingly we may observe 

 manifestations of pain, extended head and neck, 

 the animals often shaking their heads. Incomplete closure 

 of the pharyngeal openings results in food particles entering 

 the larynx or nasal cavities and giving rise to cough, or 

 ejections of water, saliva or food through the nostrils (re- 

 gurgitation), as the case may be. The degree to which the 

 closure of the pharyngeal openings is imperfect, bears a 

 direct relation to the severity of the affection. In mild cases, 

 fluid only is regurgitated, noticeable while drinking water. 

 Later on as the case becomes aggravated, solids also pass 

 out. When the affection is mild and restricted to one side 

 the regurgitation may also be unilateral. Soft feed is more apt 

 to cause regurgitation than are solid substances. An inflam- 

 matory affection of the pharynx that causes difficulties in deg- 

 lutition may be primary (pharyngitis), or secondary to other 

 diseases : distemper, morbus maculosus, anthrax. 



In addition, difficult deglutition is observed in: 



Paralysis of the pharynx in mycoses, parturient paresis 

 and rabies. 



Spasm of the pharyngeal muscles in tetanus. 



Tumors of the pharynx; actinomycoma, lymphoma, tu- 

 bercular lymph glands. 



