46 ELEMENTS OF HISTOLOGY. ichap. vi. 



55. (1) Hyaline cartilage (Fig. 30A). This occurs 

 on the articular surfaces of all bones ; on the borders 

 of many short bones ; in the sternal part of the ribs, 

 as costal cartilages ; at the margin of the sternum, 

 scapula, and os ileum ; in the rings of the trachea, the 

 cartilages of the bronchi, the septum and lateral carti- 

 lages of the nose ; and in 

 the thyroid and cricoid 

 cartilages of the larynx. 

 The ground substance is 

 hyaline, i.e., transparent, 

 like ground - glass, and 

 firm. The cells are 

 spherical or oval proto- 

 plasmic corpuscles, each 

 with one or two nuclei. 

 Fig ' 3 A k~uSn al ^ e ach C e? tilae The y undergo division, 



In the hyaline ground substance are and although the two off- 



p2uie& cartils spring are at first close 



together (half-moon-like 



in optical section), they gradually grow wider apart 

 by the deposit of hyaline ground substance between 

 them. The cells are contained in cavities called the 

 cartilage lacunce. Each cell generally occupies one 

 lacuna, but according to the state of division a lacuna 

 may contain two, four, six, or eight cartilage cells ; 

 the latter are those cases in which division proceeds 

 at a more rapid rate than the deposition or formation 

 of hyaline ground substance between the cells. 



The part of the cartilage next to the perichondrium 

 shows most active growth ; hence the cells are here smaller, 

 closer together, and there is less ground substance. 



Each lacuna is lined by a delicate membrane, and, 

 according to the state of the cell, is either com- 

 pletely or partially filled out by it. This membrane 

 is called the capsule (Fig. 30A). In many cartilages, 

 especially in growing cartilage, it is thickened by the ad- 



