312 



THE LARYNX, LUNGS, VOCAL SACS, ETC. 



by which the supply of air to the lungs, and the voice can be 

 regulated. 



a. The cartilages of the larynx. 



The cartilages of the larynx are five in number, of which four are 

 paired and one is single. 



(i) The cricoid cartilage (Figs. 203, 204) is an oval ring of 

 cartilage with various processes. The ring-like portion of the 

 cartilage is placed in a plane which is almost vertical, but which 

 is directed slightly upwards anteriorly, and slightly downwards 

 posteriorly (the animal being in the usual sitting position). 



Fig. 203. 



11. 



Ca 



SR 



C.I? 



C.I? 



C.I 2 



-Sp 



The cartilaginous skeleton of the larynx. 



I. Seen from in front ; the spinous process would normally be more curved. 

 II. Seen from the left side ; the spinous process should be more curved. 

 Ca Right arytenoid cartilage. SR Opening to larynx. 



6 T al Left arytenoid cartilage. * * * The two outer asterisks are above the two 



C.U-C.IA Cricoid cartilage. apices of the left arytenoid cartilage ; the 



P Lateral plate of cricoid cartilage. middle one above the pre-arytenoid carti- 



Sp Spine of cricoid cartilage. lage. 



The sides of the ring are slightly curved inwards on the anterior 

 surface, and possessed of irregular enlargements (C.l. l -C.l.^), the space 

 enclosed by this portion of the cartilage is occupied by a membrane 

 (J/), which forms the floor of the body of the larynx. 



From each side of the body of the cartilage, a process (C.I.' 2 ) is 

 given off, which curves backwards and inwards to join its fellow of 

 the opposite side, the two forming a blunt spinous process (Sjj), which 

 projects backwards, and is intimately attached to the oesophagus. 

 Between these processes and the lower portion of the body of 



