CH. LIV.] 



THE LARYNGOSCOPE. 



733 



is for this purpose provided with a ball-and-socket joint, that a beam of 

 light is reflected on the lips of the patient. 



The patient is now directed to throw his head slightly backwards, and to 

 open his mouth ; the reflection from the mirror lights up the cavity of the 

 mouth, and by a little alteration of the distance between the operator and 

 the patient the point at which the greatest amount of light is reflected by 

 the mirror in other words, its focal length is readily discovered. The 

 small mirror fixed in the handle is then warmed, either by holding it over 

 the lamp, or by putting it into a vessel of warm water ; this is necessary to 

 prevent the condensation of breath upon its surface. The degree of heat is 

 regulated by applying the back of the mirror to the hand or cheek, when it 

 should feel warm without being painful. 



After these preliminaries the patient is directed to put out his tongue, 

 which is held by the left hand gently but firmly against the lower teeth by 

 means of a handkerchief. The warm mirror is passed to the back of the 

 mouth, until it rests upon and slightly raises the base of the uvula, and at 

 the same time the light is directed upon it : an inverted image of the 

 larynx and trachea will be seen in the mirror. If the dorsum of the tongue 

 is alone seen, the handle of the mirror must be slightly lowered until the 



Fig- 555- To show the position of the operator and patient when using the Laryngoscope. 



larynx comes into view ; care should be taken, however, not to move the 

 mirror upon the uvula, as it excites retching. The observation should not 

 be prolonged, but should rather be repeated at short intervals. 



The structures seen will vary somewhat according to the condition of the 

 parts as to inspiration, expiration, phonation, &c. ; they are (fig. 556) first, 

 and apparently at the posterior part, the base nf tJie tongue, immediately 

 below which is the arcuate outline of the tpiflottit, with its cushion or 

 tubercle. Then are seen in the central line the true vocal cords, white and 

 shining in their normal condition. The cords approximate (in the inverted 

 image) posteriorly ; between them is left a chink, narrow whilst a high note 

 is being sung, wide during a deep inspiration. On each side of the true 

 vocal cords, and on a higher level, are the pink / Aw- roml rord*. Still more 

 externally than the fake vocal cords is the arytemi-rpiylottidcun fold, in 

 which are situated upon each side three small elevations ; of these the most 

 external is the ctirtUnyi- of \Vrixberg, the intermediate is the i-urtiltitji' of 

 Santortni, whilst the summit of the urijh-nniil mrtilagr is in front, and 

 somewhat below the preceding, being only seen during deep inspiration. 



