92 



OSTEOLOGY 





interior the cells or osteoblasts predominate; the whole tissue is richly supplied with 

 bloodvessels. At the outset of the process of bone formation a little network 

 of spicules is noticed radiating from the point or center of ossification. These 

 rays consist at their growing points of a network of fine clear fibers and granular 



Haversian canal 



Bone corpuscle 



Bone corpuscle 

 between inter- 

 stitial lamellae 



Fio. 77. Transverse section of body of human fibula, decalcified. X 250. 



corpuscles with an intervening ground substance (Fig. 78). The fibers are termed 

 osteogenetic fibers, and are made up of fine fibrils differing little from those of white 

 fibrous tissue. The membrane soon assumes a dark and granular appearance from 

 the deposition of calcareous granules in the fibers and in the intervening matrix, 



;sr 



spicules 



Calcified deposit 

 between the fibers 



Bony spicules 

 Fio. 78. Part of the growing edge of the developing parietal bone of a fetal cat. (After J. Lawrence.) 



and in the calcified material some of the granular corpuscles or osteoblasts are 

 enclosed. By the fusion of the calcareous granules the tissue again assumes a 

 more transparent appearance, but the fibers are no longer so distinctly seen. 

 The involved osteoblasts form the corpuscles of the future bone, the spaces in 



