1078 



THE KESPIEATOEY SYSTEM. 



In such an examination the arched upper border of the epiglottis is a conspicuous object, 

 whilst, dorsal to that, the bulging on the ventral wall of the vestibule, formed by the tubercle 

 of the epiglottis, may also be a feature of the picture. The median glosso-epiglottic fold 

 with the glosso-epiglottic vallecula on either side of it, can also be inspected in the interval 

 between the epiglottis and the base of the tongue. The sharp aryepiglottic folds are 

 clearly visible, and in the dorsal portion of each can be seen the two prominent tubercles 

 which are formed by the enclosed cuneiform and corniculate cartilages. Dorsal to those 

 tubercles is the dorsal wall of the pharynx, whilst to their lateral side the deep piriform 



Median glosso-epiglottic fold 

 Tuberculum epiglotticum I Dorsum of tongue 



Plica vocalis 



Vallecula 



Ventriculus laryngis 

 Recessus pirifonnis 



Aryepiglottic fold 



Processus vocalis of 

 arytsenoid cartilage 



Epiglottis 



Rings of trachea 

 B 



Tuberculum 

 Cuneiforms 



Tuberculum corniculatum 



FIG. 857. CAVITY OF THE LARYNX, as seen by means of the laryngoscope. 

 A. Eirna glottidis closed. B. Rima glottidis widely opened. 



recess may be seen. In the interior of the larynx the ventricular and the vocal folds are easily 

 recognised, and the interval between the two, or, in other words, the entrance into the laryngeal 

 ventricle, appears as a dark line on the lateral wall of the larynx. The ventricular folds are red 

 and fleshy-looking ; the vocal folds during phonation are tightly stretched and pearly white 

 the white colour being usually more apparent in the female than in the male. The outline 

 and yellowish tinge of the vocal process at its attachment to the vocal fold, and the outline of the 

 ventral part of the base of the arytaenoid cartilage to a slight extent as well, can be made out in a 

 successful laryngoscopic examination. The vocal folds during ordinary inspiration are seldom 

 at rest, and with the laryngoscope their movements may be studied. It should be borne in mind 

 that the picture afforded by the laryngoscope does not give a true idea of the level at which the 

 different parts lie. The cavity appears greatly shortened, and its depth diminished. 



TKACHEA. 



The trachea or windpipe is a wide tube which is kept permanently patent by 

 a series of bent cartilaginous bars embedded in its wall. These bars are deficient 

 dorsally, and consequently the tube is not completely cylindrical : its dorsal wall 

 is flattened. The trachea begins at the inferior border of the cricoid cartilage, 

 opposite the inferior margin of the sixth cervical vertebra. From that level it 

 extends, through the neck, into the superior mediastinum of the thorax, and it 

 ends, at the level of the superior border of the fifth thoracic vertebra, by dividing 

 into the right and left bronchi. The length of the trachea in the male is from 

 four to four and a half inches, and in the female from three and a half to four 

 inches, but even in the same individual it varies considerably in length with the 

 movements of the head and neck. 



The inferior end of the trachea is fixed in position. This is a necessary provision to 

 prevent dragging on the roots of the lung during movements of the head and neck. 

 The remainder of the tube is surrounded by a quantity of loose areolar tissue, and 

 possesses a considerable amount of mobility. Further, its wall is highly elastic, and thus 

 when the head is thrown back the tube elongates through stretching, and when the chin 

 is depressed its length is diminished by the recoil of its wall. 



The trachea does not present an absolutely uniform calibre throughout its 

 whole length. About its middle it exhibits a slight expansion or dilatation, and 

 from that the calibre diminishes towards both extremities. Close to the bifurca- 

 tion it is again slightly expanded (Braune and Stahel). 



