44 ELEMENTARY TISSUES. 



lacement 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 distri- 

 buted throughout the body, 

 than the foregoing kind, is 

 composed, like it, of cells and 

 a matrix; the latter, however, 

 being made up almost entirely 

 of fibres closely resembling 

 those of white fibrous tissue. 

 In this kind of fibro-car- 

 tilage 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 por- 

 tion, continuous with it, cartilage cells may be pretty freely 

 distributed. 



The different situations in which white fibro-cartilage is 

 formed have given rise to the following classification : 



1. Inter-articular fibro-cartilage, e.g., the semilunar car- 

 tilages of the knee-joint. 



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

 acetabulum and glenoid cavity of the scapula. 



3. Connecting, e.g., the inter-vertebral 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-carti- 

 lage, of which a specimen may be found in the tendon of 

 the tibialis posticus, in the sole of the foot, and usually in 

 the neighbouring tendon of the peroneus longus. 



The uses of cartilage are the following : in the joints, 

 to form smooth surfaces for easy friction, and to act as a 

 buffer, in shocks ; to bind bones together, yet to allow a 

 certain degree of movement, as between the vertebra} ; to 



* Fig. 15. Section of the epiglottis, magnified 380 diameters (Dr. 

 Baly). 



