THE LARYNX 



425 



Epiglottis 



Hyoid 



a short posterior part and a longer anterior part. The outer 

 surface of the lamina is relatively flat. Immediately below 

 the posterior part of the upper border, and anterior to the root 

 of the superior cornu, there is a distinct prominence called the 

 superior tubercle. From this an oblique ridge descends towards 

 the inferior tubercle on the lower border of the lamina. This 

 ridge gives attachment to the sterno-thyreoid, thyreo-hyoid 

 and the inferior 

 constrictor muscles, 

 and divides the 

 outer surface of the 

 lamina into an 

 anterior and a pos- 

 terior part. To the 

 latter, which is much 

 the smaller of the 

 two, is attached the 

 inferior constrictor 

 muscle of the 

 pharynx. The inner 

 surface of the lamina 

 is smooth and slight- 

 ly concave. To the 

 angular depression 

 between the two 

 laminae are attached 

 the thyreo-epiglottic 

 ligament, the ven- 

 tricular and the vocal 

 ligaments. 



Crico-thyreoid 

 Joints. The articu- 

 lation, on each side, 

 between the tip of the inferior cornu of the thyreoid car- 

 tilage and the side of the cricoid cartilage, belongs to the 

 diarthrodial variety. The opposed surfaces are surrounded 

 by a capsular ligament which is lined with a synovial stratum. 

 The movements which take place at these joints are of a 

 twofold character viz., (i) gliding; (2) rotatory. In the 

 first case the cricoid facets glide upon the thyreoid surfaces in 

 different directions. The rotatory movement is one in which 

 the cricoid cartilage rotates around a transverse axis which 



Cartilage triticea 

 Thyreo-hyoid 



membrane 



Superior cornu 



of the thyreoid 

 cartilage 



Superior tubercle 



- Oblique line 

 Inferior tubercle 

 Inferior cornu 



Conus elasticus 



Cricoid cartilage 



FIG. 



167. Profile view of Cartilages and 

 Ligaments of Larynx. 



