no Deglutition 



far are concerned. If the student will try to swallow with the mouth 

 open and the lower jaw unfixed, he will accomplish the act only with 

 difficulty ; but if he fixes the lower jaw by biting something, though 

 the mouth remains widely open, the act is readily accomplished. 



In the second stage of deglutition the soft palate is raised by the 

 food being pushed against it by the tongue, and is fixed and tightened 

 by the levator and tensor ; the palato-pharyngei are also fixed, and, the 

 posterior wall of the pharynx being drawn forwards by the superior 

 constrictor, the back-way into the nares is completely shut off. (If 

 the soft palate be cleft or perforated, it is at this stage that the food 

 passes into the nose, to be ejected by the anterior nares.) 



The larynx is now drawn forwards, and, the tongue being thrust 

 backwards, the glottis is protected beneath its hinder part, the epi- 

 glottis also being shut down. 



In diphtheritic paralysis of the soft palate food passes through the 

 nostrils, or, at this stage of deglutition, if the muscles of the larynx and 

 tongue be not working in harmony, some ' goes the wrong way ' into 

 the larynx and sets up coughing, or, perhaps, food-pneumonia. To 

 avoid these risks, therefore, such patients must be fed by a soft catheter 

 introduced into the pharynx through the inferior meatus of the nose. 



In the third stage the constrictors take charge of the bolus, and, the 

 larynx dropping, the food is carried from the posterior air-way, and 

 hurried down the oesophagus. 



The nerves concerned in the reflex act of deglutition are first those 

 which convey the stimulus (afferent) to the medullary centre ; they 

 are palatine branches of the fifth, pharyngeal of glosso-pharyngeal, and 

 oesophageal of vagus. The efferent or motor nerves are the hypo- 

 glossal (for first stage), mylo-hyoid of inferior maxillary, and pharyn- 

 geal branches of vagus which have come from spinal accessory. 



The uvula consists of a double layer of mucous membrane with 

 the azygos muscle included between them. Its office is not clearly- 

 known. Some compare it to a gargoyle which guides the mucus 

 from the nares to the back of the tongue and prevents its dripping 

 into the glottis. Others deem it to be needful to fill in the interval 

 between the posterior pillars of the fauces, and to block the naso- 

 pharyngeal straits during deglutition. Nevertheless, many are benefited 

 by its partial amputation. 



In certain people it is greatly elongated ; and, its blood-vessels 

 being dilated after swallowing anything hot, or after smoking, it hangs 

 against and tickles the back of the tongue to such an extent as to set 

 up uncontrollable cough or retching. A medical friend of my own 

 who possessed a long uvula, and a strange aversion from the perform- 

 ance of even a slight operation upon himself, was through five consecu- 

 tive nights kept awake by a distressing uvula-cough. The ultimate 

 removal, however, of half an inch of the cedematous mass brought him 

 absolute and permanent relief. 



