PRACTICAL PHYSIOLOGY. 



[LXVII. 



laryngeal mirror, when an inverted image of the larynx will be 

 seen more or less perfectly. 



(d.) By moving the laryngeal mirror, not, however, pressing too 

 much on the uvula, or continuing the observation for too long a 

 time, one may explore the whole of the larynx. Perhaps only the 

 posterior part of the dorsum of the tongue is seen at first ; if so, 

 slightly depress the handle of the mirror, when the curved fold of 

 the slightly yellowish epiglottis and its cushion, with the glosso- 

 epiglottidean folds, come into view. In the middle line are the 

 irue vocal cords, which are pearly white and shining, and best seen 

 when a high note is uttered, and between them the chink of the 

 glottis. Above these are the false vocal cords, which are red or 

 pink, the ary-epiylottidean folds, with on each side the cartilages of 

 Wrisberg farthest out, the cartilages of Santorini internal to this, 

 and the arytenoid cartilages near the middle line (figs. 240, 241). 



FIG. 240. View of the Larynx during a 

 Deep Inspiration, g.e. Glosso-epi- 

 glottidean fold ; I.e. Lip and cushion 

 of epiglottis; a.e. Ary-eptelottic 

 fold; c.W., c,.S. Cartilages of Wris- 

 berg and Santorini ; v.c. Vocal cord ; 

 v.b. Ventricular band ; p.v. Processus 

 vocalis; c.r. Cricoid cartilage; t. 

 Rings of trachea. 



Fl<3. 241. Larynx during Vocalisation. 

 f.i. Fossa innominate ; h.f. Hyoid 

 fossa ; com. Arytenoid commissure. 



(e.) Make the patient sing a deep or high note, or inspire feebly 

 or deeply, and observe the change in the shape of the glottis. On 

 uttering a deep note, the rings cf the trachea may be seen. N. B. 

 Remember that what is seen by the observer in the laryngeal 

 mirror on his right or left corresponds to the patient's left and 

 right. The lower part of the mirror gives an image of the more 

 posterior structures, while the anterior structures are reflected in its 

 upper part. 



2. Auto-Laryngoscopy. The student should learn to use the laryngoscope 

 on himself. The student sits in a chair, fixes the large reflecting mirror in a 

 suitable holder about eighteen inches in front of, and on a level with his 

 mouth. Behind and to one side of this an ordinary plane mirror is placed 

 vertically. On one side of his head he places the source of light. The light 



