1076 



SPLANCHNOLOGY 





membrane, and upper part of the thyroid cartilage, but is separated from these 

 structures by a mass of fatty tissue. 



The posterior or laryngeal surface is smooth, concave from side to side, concavo- 

 convex from above downward; its lower part projects backward as an elevation, 

 the tubercle or cushion. When the mucous membrane is removed, the surface of 

 the cartilage is seen to be indented by a number of small pits, in which mucous 

 glands are lodged. To its sides the aryepiglottic folds are attached. 



Structure. The corniculate and cuneiform cartilages, the epiglottis, and the apices of the 

 arytenoids at first consist of hyaline cartilage, but later elastic fibers are deposited in the matrix, 

 converting them into yellow fibrocartilage, which shows little tendency to calcification. The 

 thyroid, cricoid, and the greater part of the arytenoids consist of hyaline cartilage, and become 

 more or less ossified as age advances. Ossification commences about the twenty-fifth year in 

 the thyroid cartilage, and somewhat later in the cricoid and arytenoids; by the sixty-fifth year 

 these cartilages may be completely converted into bone. 



Lateral hyothyroid ligament 

 Internal laryngeal nerve 

 Cartilage tnticea 



Superior laryngeal artery 



Superior cornu 

 Thyroid notch 



Oblique line 



Conus elasticity (lateral parts) 



Middle cricothyroid ligament 

 'Inferior cornu 



FIG. 951. The ligaments of the larynx. Antero-lateral view. 



Ligaments. The ligaments of the larynx (Figs. 951, 952) are extrinsic, i. e., those 

 connecting the thyroid cartilage and epiglottis with the hyoid bone, and the cricoid 

 cartilage with the trachea; and intrinsic, those which connect the several cartilages 

 of the larynx to each other. 



Extrinsic Ligaments. The ligaments connecting the thyroid cartilage with the 

 hyoid bone are the hyothyroid membrane, and a middle and two lateral hyo- 

 thyroid ligaments. 



The Hyothyroid Membrane (membrana hyothyreoidea; thyrohyoid membrane) is 

 a broad, fibre-elastic layer, attached below to the upper border of the thyroid 

 cartilage and to the front of its superior cornu, and above to the upper margin of 

 the posterior surface of the body and greater cornua of the hyoid bone, thus passing 

 behind the posterior surface of the body of the hyoid, and being separated from it 



