416 



HEAD AND NECK 



the intermediate fibres are the longest, and are very oblique ; whilst the 

 lowest fibres are almost vertical in their direction. 



Musculus Arytaenoideus. The arytaenoid muscle consists 

 of two portions a superficial part, termed the arytcenoideus 

 obliquuS) and a deeper layer, called the arytcenoideus transversus. 



The arytcenoideus obliquus is composed of two bundles of 

 muscular fibres, each of which springs from the posterior aspect 

 of the muscular process of the corresponding arytaenoid 



Epiglottis 

 i^f Great cornu of hyoid 



*--Ary-epiglottic fold 



Triticeal cartilage 



- Thyreo-hyoid membrane. 



-Thyreoid cartilage 



Union of oblique arytaeno 

 deus and ary-epiglotticus 

 - Transverse arytaenoideus 



_. Crico-arytaenoideus 

 posterior 



...Median ridge of cricoid 

 lamina 



-Cartilage ring of trachea 



Muscular part of trachea 



FIG. 162. Muscles of the Posterior Aspect of the Larynx. 



cartilage (Fig. 162). From these points the two fleshy slips 

 proceed upwards and medially, and cross each other in the 

 median plane like the limbs of the letter X. Reaching the 

 summit of the arytaenoid cartilage of the opposite side, some 

 of the fibres are inserted into it, but the greater proportion 

 are prolonged, round the base of the corniculate cartilage, 

 into the ary-epiglottic fold. There they receive the 

 name of the ary-epiglotticus muscle, and as they approach 

 the epiglottis they are joined by the fibres of the thyreo- 

 epiglotticus muscle. The oblique arytaenoid muscles may 

 be considered as constituting a weak sphincter muscle 



