CARTILAGE. 43 



The cells, which contain a nucleus with nucleoli, are 

 irregular in shape, and generally grouped together in 

 patches. The patches are of various shapes and sizes, and 

 placed at unequal distances apart. They generally appear 

 flattened near the free surface of the mass of cartilage in 

 which they are placed, and more or less perpendicular to 

 the surface in the more deeply seated portions. 



The matrix in which they are imbedded has a dimly 

 granular appearance, like that of ground glass. 



In the hyaline cartilage of the ribs, the cells are mostly 

 larger than in the articular variety, and there is a tendency 

 to the development of fibres in the matrix. The costal 

 cartilages also frequently become ossified in old age, as 

 also do some of those of the larynx. 



Temporary cartilage closely resembles the ordinary 

 hyaline kind ; the cells, however, are not grouped together 

 after the fashion just described, but are more uniformly 

 distributed throughout the matrix. 



Articular hyaline cartilage is reckoned among the so- 

 called non-vascular structures, no blood-vessels being sup- 

 plied directly to its own substance; it is nourished by 

 those of the bone beneath. When hyaline cartilage is in 

 thicker masses, as in the case of the cartilages of the ribs, 

 a few blood-vessels traverse its substance. The distinction, 

 however, between all so-called vascular and non-vascular 

 parts, is at the best a very artificial one. (See chapter on 

 Nutrition.) 



Nerves are probably not supplied to any variety of 

 cartilage. 



Fibrous cartilage, as before mentioned, occurs under two 

 chief forms, the yellow and the white fibro-cartilage. 



Yellow fibro-cartilage is found in the external ear, in the 

 epiglottis and cornicula laryngis, and in the eyelid. The 

 cells are rounded or oval, with well-marked nuclei and 

 nucleoli. The matrix in which they are seated is composed 

 almost entirely of fine fibres, which form an intricate inter- 



