486 



MUSCLES OF THE LARYNX. 



Use. To shut the rima glottidis, by bringing these two carti- 

 lages, with the ligaments, nearer one another. 



Fig. 124.* Besides these, there are a few separate 



muscular fibres on each side ; which, from 

 their general direction, are named 



1 . Thyro-Epiglottideus, 

 Arises, by a few pale separated fibres, 



from the thyroid cartilage : and is 

 Inserted into the epiglottis laterally. 

 Use. To draw the epiglottis obliquely 



downwards, or, when both act, directly 



downwards ; and at the same time, it expands 



that soft cartilage. 



2. Arytano-Epiglottideus, superior. 



Arises, by a number of small fibres, from the lateral and 

 upper part of the arytenoid cartilage ; and, running along the 

 outer side of the external rima, is 



Inserted into the epiglottis along with the former. 



Use. To pull that side of the epiglottis towards the external 

 rima ; or, when both act, to pull it close upon the glottis. It is 

 counteracted by the elasticity of the epiglottis. 



3. Aryteno-Epiglottideus, inferior. 



— This muscle may be exposed by raising the mucous mem- 

 brane immediately above the ventricle of the larynx. It arises 

 by a narrow and fibrous origin from the arytenoid cartilage, 

 just above the attachment of the chorda vocalis — and passing 

 forwards and a little upwards, expands over the upper half or 

 two-thirds of the sacculus laryngis, and is inserted by a broad 

 attachment into the side of the epiglottis. Its action according 



* A side view of the larynx, one ala of the thyroid cartilage has beea 

 removed. 1. The remaining ala of the thyroid cartilage. 2. One of the 

 arytenoid cartilages. 3. One of the cornicula laryngis. 4. The crycoid carti- 

 lage. 5. The crico-arytenoideus posticus muscle. 6. The crico-arytenoideus 

 lateralis. 7. The thyro-arytenoideus. 8. The crico-thyroidean membrane. 

 9. One half of the epiglottis. 10. The upper part of the trachea. 



