280 



SYNDESMOLOGY 



with each other, and in the rest of their circumference are rounded. They con- 

 sist of clear translucent protoplasm in which fine interlacing filaments and minut 

 granules are sometimes present; imbedded in this are one or two round nuclei, 

 having the usual intranuclear network. The cells are contained in cavities ii 

 the matrix, called cartilage lacunae ; around these the matrix is arranged in con- 

 centric lines, as if it had been formed in successive portions around the cartilage 

 cells. This constitutes the so-called capsule of the space. Each lacuna is generally 



occupied by a single cell, but dur- 

 ing the division of the cells it may 

 contain two, four, or eight cells. 



The matrix is transparent and 

 apparently without structure, or 

 else presents a dimly granular ap- 

 pearance, like ground glass. Some 

 observers have shown that the 

 matrix of hyaline cartilage, and 

 especially of the articular variety, 

 after prolonged maceration, can 

 be broken up into fine fibrils. 



These fibrils are probably of the same nature, chemically, as the white fibers 

 of connective tissue. It is believed by some histologists that the matrix is per- 

 meated by a number of fine channels, which connect the lacunas with each other, 

 and that these canals communicate with the lymphatics of the perichondrium, 

 and thus the structure is permeated by a current of nutrient fluid. 



Articular cartilage, costal cartilage, and temporary cartilage are all of the hyaline 

 variety. They present differences in the size, shape, and arrangement of their 

 cells. 



5?1 



g > Superficial flattened cells 



FIG. 292. Human cartilage cells from the cricoid cartilage. 

 X 350 



Vertical rows of cells 



Hvff^V-> f Calcified matrix 



Bone 



FIG. 293. Vertical section of articular cartilage. 



FIG. 294. Costal cartilage from a man, aged 

 seventy-six years, showing the development of 

 fibrous structure in the matrix. In several por- 

 tions of the specimen two or three generations of 

 cells are seen enclosed in a parent cell wall. 

 Highly magnified. 



In Articular Cartilage (Fig. 293), which shows no tendency to ossification, the 

 matrix is finely granular; the cells and nuclei are small, and are disposed parallel 

 to the surface in the superficial part, while nearer to the bone they are arranged in 

 vertical rows. Articular cartilages have a tendency to split in a vertical direction; 

 in disease this tendency becomes very manifest. The free surface of articular 

 cartilage, where it is exposed to friction, is not covered by perichondrium, although 

 a layer of connective tissue continuous with that of the synovial membrane can be 



