THE LARYNX 427 



band which proceeds upwards from the longitudinal fibres of 

 the oesophagus. The anterior part of the cricoid cartilage 

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

 connected to the first tracheal ring by membrane, the crico- 

 tracheal ligament. The arch is narrow anteriorly, and is 

 attached to the lower border of the thyreoid cartilage by 

 the crico- thyreoid ligament. Posteriorly, the upper border 

 rapidly ascends. 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 membrane, 

 and its lumen is circular below, but elliptical above. 



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 CorniculatsB. 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 posteriorly 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 Arytsenoidese. In dealing with the arytaenoid 

 cartilages it is well to remove one in order that its external 

 form may be studied; the other should be retained in 

 position, for the purpose of examining the crico-arytaenoid 

 joint and the movements which can be performed at that 

 articulation. 



The arytanoid cartilages are pyramidal in form, and sur- 

 mount the upper border of the lamina of the cricoid 

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

 curved postero-medially. It supports the corniculate cartilage. 

 Of the three surfaces, one looks medially, towards the corre- 

 sponding surface of the opposite cartilage, from which it is 

 separated by a narrow interval; another looks posteriorly; 

 whilst the third is directed antero-laterally. The medial 



