THE LARYNX 



and bridging across the interval between them, are the transverse 

 and oblique parts of the arytaenoid muscle. Especial care must 

 be taken whilst that muscle is being cleaned, in order that the 

 connections of the superficial decussating fibres may be ascer- 

 tained fully. 



The lateral layer of the left ary-epiglottic fold of mucous 

 membrane should now be cautiously removed, to expose the ary- 

 epiglottic muscle, the cuneiform cartilage, and the corniculate 

 cartilage of that side. This is perhaps the most difficult part of 

 the dissection, because the dissector has to establish the con- 

 tinuity of the sparse fibres, which compose the pale ary-epiglottic 

 muscle, with the decussating fibres of the arytaenoid muscle 

 (Fig. 123). 



Epiglottis 

 /A Greater cornu of hyoid 



Pr 



"T "Ary-epiglottic fold 

 i > 4--Cartilago triticea 



T - Thyreo-hyoid membrane 



.-Tliyreoid cartilage 



Union of oblique arytaenoi- 

 deus and ary-epiglotticus 

 M. arytaenoideus transversus 



M. cricoarytaenoideus 

 posterior 



Median ridge of cricoid 

 lamina 



Cartilage ring of trachea 



- Muscular part of trachea 



FIG. 123. Muscles of the Posterior Aspect of the Larynx. 



Musculus Crico-arytsenoideus Posterior. Each posterior 

 crico-arytaenoid muscle is somewhat fan-shaped (Fig. 123). 

 It springs, by a broad origin, from the depression which marks 

 the posterior surface of the cricoid cartilage, on the correspond- 

 ing side of the median ridge, and its fibres converge to be 

 inserted into the posterior surface of the muscular process or 

 projecting lateral angle of the base of the arytaenoid cartilage. 



As the fibres pass from origin to insertion, they run with 

 different degrees of obliquity. The uppermost fibres are 



