CARTILAGE. 45 



non-vascular structures, no bloodvessels being supplied directly 

 to its own substance; it is nourished by those of the bone be- 

 neath. When hyaline cartilage is in thicker masses, as in the 

 case of the cartilages of the ribs, a few bloodvessels 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 fibre-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 en- 

 tirely of fine fibres, which form an intricate interlacement 

 about the cells, and in their general characters are allied to 

 the yellow variety of fibrous tissue (Fig. 15). 



White fibro-cartilage, which is much more widely distributed 

 throughout the body than the foregoing kind, is composed like 

 it, of cells and a matrix ; the 

 latter, however, being made up Fl - 15 - 



almost entirely of fibres close- 

 ly resembling those of white 

 fibrous tissue. 



In this kind of fibro-carti- 

 lage it is not unusual to find a 

 great part of its mass composed 

 almost exclusively of fibres, and 

 deserving the name of cartilage 

 only from the fact that in 

 another portion, continuous 

 with it, cartilage-cells may be 



nrettv freelv distributed Sectlou of the e ^ loiiis ' magnified 380 



pretty I .Ciy a ea. diameters (Dr. Baly). 



Ihe different situations in 



which white fibro-cartilage is formed have given rise to the 

 following classification : 



1. Interarticular fibro-cartilage, e. g., the semilunar carti- 

 lages of the knee-joint. 



2. Circumferential or marginal, as on the edges of the ace- 

 tabulum and glenoid cavity of the scapula. 



3. Connecting, e. g., the intervertebral fibro-cartilages. 



4. Fibro-cartilage is found in the sheaths of tendons, and 

 sometimes in their substance. In the latter situation, the 

 nodule of fibro-cartilage is called a sesamoid fibro-cartilage, of 

 which a specimen may be found in the tenclon of the tibialis 



