CARTILAGE. 



33 



Elastic cartilage, called also yellow elastic and reticular cartilage 

 (Fig. 46), has a limited distribution, occurring principally in the cartilages 

 of the external ear, lower 

 part of the Eustachian tube, 



and in parts of the larynx, :-fc 



namely, the epiglottis, the - r - 



cuneiform and corniculate 



cartilages and the vocal r^ \ 



processes and apices of the f _ ^ 



arytenoids. * In its physical 

 properties this variety differs 

 from hyaline cartilage, as it 

 is dull yellowish in color and 

 pliable and tough in con- 

 sistence, in contrast to the 

 bluish opalescent tint and 

 comparative brittleness of 

 hyaline cartilage. 



The characteristic his- 



tological feature of elastic *> 



cartilage is the presence of 

 elastic fibres within the inter- 

 cellular matrix. The lacunas 

 containing the cartilage- 

 cells are 'immediately sur- 

 rounded by limited areas of 

 hyaline matrix, the so-called "capsules 



Cartilage-cells 



Area of hyaline 

 matrix 



Network of elastic 



fibres 



Lacuna containing' 

 cartilage-cefl 



FIG. 46. Section of elastic cartilage from the epiglottis. X 360. 



Of 



some authors. The matrix 

 between these homogene- 

 ous areas, however, is pene- 

 trated by delicate and often 

 intricate networks of elastic 

 fibres. The latter respond, 

 as in other localities, to spe- 

 cific stains. The method by 

 which the elastic fibres de- 

 velop is uncertain, although 

 their production nv.ist be 

 attributed to the influence of 

 the cells. Since the fibres 

 appear relatively late and 

 within the matrix often at 

 some distance from the car- 

 tilage-cells, it is probable 

 that they do not arise within 

 the exoplasm of the cells. 

 The elastic cartilages are 

 surrounded by a perichon- 

 drium of the usual descrip- 

 tion. 



FIG. 47. Section of fibrous cartilage from intervertebral disk. FibfOUS Cartilage, or 



fibrocartilage (Fig. 47), is 



found in comparatively few localities, although it occurs- in masses of 

 considerable bulk. Its chief situations are the intervertebral disks, the 



