ANATOMY OF THE LARYNX. 



485 



The arytenoid cartilages are little three-sided 

 pyramidal masses placed on the upper surface 

 of the posterior part of the cricoid, to which 

 they are attached by a loose joint. They are 

 so placed that one surface looks inwards, the 

 second backwards, and the third forwards and 

 outwards, while the inferior surface rides on the 

 cricoid. One point, therefore, looks forwards, 

 and to it is attached the vocal cord on each 

 side, hence it has been called the vocal process. 

 The apex, which looks outwards and back- 

 wards, gives attachment to some of the in- 

 trinsic muscles, and hence has been called the 

 muscular process. 



The thyroid cartilage is connected with 

 the cricoid below, and to the hyoid bone 

 above by ligaments and tough membranes, 

 which hold the parts together, fill in the 

 intervals, and complete the skeleton of the 

 larynx. 



The vocal cords are composed of small 

 strands of elastic tissue, which are stretched 

 between the anterior processes of the arytenoid 

 cartilages and the inferior part of the thyroid, 

 where they are attached side by side to the 

 posterior surface of the angle formed by the 

 junction of the two lateral parts or alae of the 

 thyroid. The mucous membrane which lines 

 the larynx is thin, and closely adherent over 

 the vocal cords. The surface of the laryngeal 

 cavity is smooth and even, the lining membrane 

 passing over the cartilages and muscles so as 

 to obliterate all ridges except the vocal cords 

 and two others, less sharply defined, called the 

 false vocal cords, which lie parallel to and 

 above the true vibrating cords. Between 

 these is the cavity known as the ventricle of 

 the larynx. 



Three diagrams 

 taken from lary ngo- 

 scopic views of the 

 superior aperture of 

 the larynx, showing 

 the position of the 

 vocal cords and the 

 arytenoid cartilages 

 supposed to be seen 

 in transverse sec- 

 tion during differ- 

 ent actions of the 

 larynx. A'. Vocal 

 chink as in singing. 

 B X In easy quiet in- 

 halation of air. c / . 

 In forced inspira- 

 tion. 



