THE FUNCTIONS OF THE UVULA. 



27 



The favorable opportunity for observing what assistance is rendered by 

 the azygos prominence and the uvula, is during the phonation of such 

 sounds as are required to pass through the mouth and nose at the same 

 time. While these sounds were uttered, the soft palate was either sus- 

 pended, so that but a small part of its central portion and the uvula rested 

 on the base of the tongue (Fig. 6), or it was raised to such a height that the 

 azygos prominence touched the posterior wall of the pharj^nx (Fig. 3). In 

 each situation that the velum occupied, the communication between the 

 fauces and the mouth, and between the fauces and the pharyngo-nasal 

 cavity, was divided into iwo equal, or nearly equal, semi-lunar openings. 

 In the first position named, the division was made by the uvula and a small 

 part of the central portion of the velum resting on the base of the tongue 

 (Fig. 6, S-1), and in the second position, the partition was made by the 

 azygos prominence (Fig. 3, S-1), touching the posterior wall of the pharynx. 



FIG. 6. View of tlie anterior surface of the soft palate, the uvula and the base of the tongue, show- 

 ing the lower sejni-lunar-shaped openings (S-l-) formed by the uvula (U.) and a part of the central portion 

 of the velum resting on the base of the tongue (,B. T.). 



In one patient I noticed, on several occasions, that the uvula seemed to 

 be resting on the base of the tongue, while, at the same time, the azygos 

 prominence was touching the posterior wall of the pharynx. 



The formation of the inferior or posterior surface of the uvula (Fig. 3, 

 U), as well as the peculiar position in which it hangs from the velum (Figs. 

 1 and 2, U), indicates that this surface lies on the base of the tongue fre- 

 quently, its extremity being directed forward (Fig. 4). It is evident that 

 this position is the best one in which it could be placed, to prevent the free 

 edge of the soft palate from being shaken by the force of the air from the 

 lungs. 



It was observed repeatedly, that the f/ee border of the velum was not 

 at any time suspended in the current of air during vocalization, but was 

 always situated in such positions that it received support, which prevented 

 it from being thrown into vibrations by the force of the air that came from 

 the larynx. To show how the support was given, I will mention again all of 

 the principal positions that this vocal valve was observed to assume, (a.) It 

 was either elevated and pressed against the posterior wall of the pharynx 

 (Fig. 5, U), during the phonation of sounds that passed through the mouth 

 alone; or, (h.) removed from this wall a small distance, but not so far as to 

 prevent the azygos prominence from touching it (Fig. 3, seen in the image 

 on the reflector E.), for sounds that passed mostly through the mouth and 

 a little through the pharyngo-nasal cavity; or, (c.) lowered to allow the 



