1070 



THE KESPIKATOEY SYSTEM. 



Hyoid bone 



Hyo-epiglottie ligament 



Cartilage of epiglottis 

 Fatty pad 

 Hyo-thyreoid membrane 



Thyreoid cartilage 

 f Elevation produced by 

 ' cuneiform cartilage 



Ventricular fold 



Philtrum ventriculi 



Laryngeal ventricle 

 Vocal fold 

 Arytsenoid muscle 

 Processus vocalis 



Cricoid cartilage 

 Cricoid cartilage 



The ventricular folds (O.T. false vocal cords) are two prominent folds of 

 mucous membrane which extend ventro-dorsally on the lateral walls of the 



laryngeal cavity. Ventrally they reach the 

 angle between the two laminae of the 

 thyreoid cartilage, but dorsally they do not 

 extend so far as the dorsal wall of the 

 larynx. They come to an end at the in- 

 ferior extremity of the elongated swelling 

 produced by the cuneiform cartilage. The 

 ventricular fold is soft and somewhat flaccid, 

 and presents a free border which is slightly 

 arched the concavity looking downwards. 

 Within the fold of mucous membrane which 

 forms this fold are contained : (1) the feeble 

 ventricular ligament ; (2) numerous glands 

 which are chiefly aggregated in its middle 

 part ; and (3) a few muscle fibres. 



The interval between the ventricular 

 folds is sometimes termed the rima vestibuli 

 (O.T. false glottis), and is considerably wider 

 than the interval between the two vocal 

 folds, which is called the rima glottidis. It 

 follows, from this, that when the cavity of 

 the larynx is examined from above the four 

 folds are distinctly visible, but when ex- 

 amined from below the vocal folds alone 

 can be seen. 



The vocal folds (O.T. true vocal cords), 

 placed below the ventricular folds, extend 

 from the angle between the laminae of the 

 FIG. 851. SECTION THROUGH LARYNX IN THE thyreoid cartilage ventrally, to the vocal 



MEDIAN PLANE TO SHOW THE SIDE WALL pr0 cesses of the arytsenoid cartilages dorsally. 



OF THE RIGHT HALF. *L t J 



I he vocal told is sharp and prominent, and 



the mucous' membrane which is stretched over it is very thin and firmly bound 

 down to the subjacent ligament. In colour it is pale, almost pearly white, whilst, 

 dorsally, the point of the processus 

 vocalis of the arytsenoid, which stands 

 out clearly in relief, presents a yellowish 

 tinge. In cross-section the vocal fold is 

 prismatic in form, and its free border 

 looks upwards as well as medially. 



The vocal folds are the agents by 

 means of which the voice is produced. 

 The ventricular folds are of little im- 

 portance in this respect ; indeed, they 

 can in great part be destroyed and no 

 appreciable difference in the voice result. 



Rima Glottidis. This name is ap- 

 plied to the elongated fissure by means 

 of which the middle compartment of the 



Thyreoid cartilage 



Vocal ligament 



Rima 



Arytsenoid 

 cartilage 



Vocal process 

 of arytsenoid 

 cartilage 



larynx communicates with the lower com- 

 partment. It is placed somewhat below 

 the middle of the laryngeal cavity, of 

 which it constitutes the narrowest part. 

 Ventrally it corresponds to the interval FIG. 852. DIAGRAM OF RIMA GLOTTIDIS. 



between the VOCal folds ; dorsally it COrre- A. During ordinary easy breathing. B. Widely opened. 



spends to the interval between the bases 



and vocal processes of the arytsenoid cartilages. It is composed, therefore, of two 



distinct parts: (1) a narrow ventral portion, between the vocal folds, involving 



