THE CONNECTIVE TISSUES. 



[CH. V. 



As connecting cartilage e.g., the inter-vertebral discs. 



In the sheaths of tendons and sometimes in their substance. 



In the latter situation the 

 nodule of fibro-cartilage is 

 called a sesamoid fibro-car- 

 tilage, 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. 



White fibro - cartilage 

 (fig- 79) i s composed of 

 cells and a matrix. The 

 latter is permeated by 

 fibres of the white 

 variety. 



In this kind of fibro- 

 cartilage it is not un- 

 usual to find portions so 

 densely fibrous that no 

 cells can be seen ; but 

 continuous with these, cartilage-cells are freely 



rr Cells of car- 

 tilage. 



... . Fibrous 

 matrix. 



Fig. 79. White fibro-cartilage. (Cadiat.) 



in other parts 

 distributed. 



Yellow or Elastic Fibro- 

 Cartilage is found in the 

 pinna of the external ear, in 

 the epiglottis and cornicula 

 laryngis, and in the Eusta- 

 chian tube. 



The cells in this variety of 

 cartilage are rounded or oval, 

 with well-marked nuclei and 

 nucleoli (fig. 80). The matrix 

 in which they are seated is 

 pervaded in all directions 

 by fine elastic fibres, which 

 form an intricate interlace- 

 ment about the cells : a 

 small and variable quantity 

 of non-fibrillated hyaline in- 

 tercellular substance is present around the cells. 



Development of Cartilage. Like other connective tissues, 



Fig. 80. Yellow elastic cartilage. (Cadiat.) 



