THE BONES. 121 
cheesy. If the separation of the periosteum from the bone is exten- 
sive the bone may undergo necrotic changes. 
What are the changes in fibrous periostitis ? 
This is a chronic inflammation of the productive class and results in 
the formation of new connective tissue in the periosteum with a conse- 
quent thickening of this membrane. 
What is an ossifying periostitis ? 
It is a process resulting in the formation of bony masses or spicule 
of bone between the periosteum and shaft of a bone. These masses, if 
circumscribed, are called osteophytes. 
What are the changes in tubercular and syphilitic periostitis ? 
In the first variety miliary tubercles are formed in the periosteum. 
In syphilitic form the specific poison may give rise to any of the pre- 
ceding varieties of periostitis except the tubercular, or there may be a 
formation of gumma tumors. 
What are the forms of osteitis ? 
Rarifying osteitis. 
Condensing osteitis. 
Suppurative osteitis. 
Tubercular osteitis. 
Syphilitic ostettis. 
What changes are seen in rarifying osteitis ? 
Under the periosteum, in the Haversian canals, and in the marrow 
spaces, there is formed a new, very cellular and vascular tissue, resem- 
bling granulation tissue. In connection with this there is an absorp- 
tion of the bony substance. In this way irregular-branching canals 
with ragged walls may be formed in the bone, or there may be irregu- 
lar masses of bone surrounded by the new tissue. 
What is condensing osteitis ? 
It is a formation of new bony material on the surface, in the mar- 
row cavities or in the Haversian canals. 
Describe suppurative osteitis. 
It usually begins as a rarifying osteitis and is really a part of an 
osteomyelitis, The marrow suppurates, the bony material is destroyed 
and a cavity is formed filled with pus and lined with granulation tissue. 
