THE LARYNX 343 



itself gives origin to a tendinous band which proceeds upwards 

 from the longitudinal fibres of the oesophagus. The anterior 

 part of the cricoid cartilage is the arch* and it narrows 

 anteriorly. The lower border of the arch is horizontal, and 

 is connected to the first tracheal ring by membrane, the 

 crico - tracheal ligament. The upper border is connected, 

 anteriorly, to the lower border of the thyreoid cartilage 'by 

 the crico -thyreoid ligament. Posteriorly, the upper border 

 rapidly ascends, and to it is attached the corresponding half 

 of the conus elasticus. Upon the posterior part of the lateral 

 surface of the cricoid cartilage there is a circular, slightly 

 elevated, convex facet, which looks laterally and upwards, for 

 articulation with the inferior cornu of the thyreoid cartilage. 

 Internally, the cricoid cartilage is lined with mucous mem- 

 brane. 



The narrow band-like part of the anterior arch of the 

 cricoid cartilage lies below the lower border of the thyreoid 

 cartilage, whilst the lamina is received into the interval 

 between the posterior portions of the laminae of the 

 thyreoid cartilage. 



Cartilagines Corniculatae. Before proceeding to the study 

 of the arytaenoid cartilages the dissector should examine the 

 corniculate cartilages and the manner in which they are 

 held in position. They are two minute pyramidal nodules 

 of yellow elastic cartilage which are placed on the summits 

 of the arytaenoid cartilages, and are directed backwards and 

 medially. Each corniculate cartilage is enclosed within the 

 corresponding ary-epiglottic fold of mucous membrane, and 

 is joined to the apex of the arytaenoid cartilage by a 

 synchondrodial joint. 



Cartilagines Arytaenoideae. Commence the study of the 

 arytaenoid cartilages by noting their relation to one another 

 and to the cricoid cartilage. Then remove one cartilage and 

 examine its surfaces and borders. Retain the other cartilage 

 in position for the purpose of examining the crico-arytaenoid 

 joint and the movements which can be performed at that 

 articulation. 



The arytcenoid cartilages are pyramidal in form, and they 

 surmount the upper border of the lamina of the cricoid 

 cartilage. The apex of each is directed upwards, and it 

 curves backwards and medially. It supports the corniculate 

 cartilage. Of the three surfaces, one looks medially, towards 



