CHAPTER VII. 

 ON SOME SPECIAL MUSCULAR MECHANISMS. 



SEC. 1. THE VOICE. 



§ 667. If a small mirror, warmed in order to avoid the con- 

 densation of moisture upon it, be placed in an appropriate slant- 

 ing position, namely, at about an angle of 45° with the horizon, 

 in the back of the pharynx with its upper margin resting against 

 the base of the uvula and be adequately illuminated, a view of 

 the interior of the larynx may be obtained. Such a mirror with 

 its various appurtenances is called a laryngoscope. The details 

 of the view thus gained will of course vary with the exact posi- 

 tion and inclination of the mirror, but the following may be 

 taken as the average appearance (Fig. 183). 



In front (reversed of course in the mirror image) will be 

 seen the edge of the back of the tongue (X), and immediately 

 in front of this the top of the epiglottis (e). These parts will 

 of necessity appear much foreshortened, and peeping out from 

 underneath the top edge of the epiglottis may be seen the swell- 

 ing at its base known as the " tubercle " or " cushion of the 

 epiglottis " (#')• The curved sides of the epiglottis will be 

 seen sweeping away to the right and to the left, and emerging 

 from near the end of each will be visible the ary-epiglottic fold 

 (ar.ep.f?) on which are obvious first the round swelling due 

 to the cartilage of Wrisberg (w) and next that due to the car- 

 tilage of Santorini (s). If at the time when the view is being 

 taken, the voice is being uttered and especially if a high note is 

 being given (Fig. 187 A) the two cartilages of Santorini are in 

 close apposition, and. the mucous membrane between is folded 

 up. If no voice is being uttered and especially if a deep inspi- 

 ration be taken (Fig. 187 B and C), the cartilages of Santorini 

 are far apart and the mucous membrane between them appears 

 as a ridge completing at the hind part the rim of the aperture 

 to the larynx ; there may also be seen on each side lying imme- 

 diately to the median side of the prominence of the cartilage 



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