, DISEASES OP BONES 181. 



chronic alveolar periostitis the tooth becomes -united to the 

 alveolar ■wall, rendering extraction at times very difficult. 

 In horses suffering with chronic bursitis intertubercularis^ 

 bony deposits upon the humerus are found. 



How do you treat ossifying periostitis ? 



By blisters and the actual cautery, and when they fail,, 

 by neurectomy. 



Describe acute purulent periostitis. 



In this form, pus-producing bacteria enter the periosteum, 

 from without — that is, through a wound of the overlying 

 soft parts, as, for instance,. in complicated fractures; or the 

 bacteria reach the periosteum from within, as in purulent- 

 myelitis ; or the infectious agent gets to the periosteum 

 through the blood current, the periosteum in such a case 

 representing a secondary or metastatic focus. 



How do you treat these cases ? 



By incision and antiseptic irrigations and dressings. 



What is a subperiosteal abscess ? 



An abscess formed under the periosteum, the result of a-. 

 purulent infection of the marrow (purulent osteomyelitis).- 

 Its treatment consists of incising the abscess and antiseptic- 

 injections. 



Describe chronic pv/rulent periostitis. 



In complicated fractures this form of periostitis, a sequel 

 to acute purulent periostitis, is quite frequently seen, there- 

 fore, in complicated fractures of the ribs, pelvis, etc., as also 

 in injuries to the interdental space by pressure from severe 

 bits and curbing, in alveolar periostitis. Fistulous tracts are 

 the consequence, because this form of periostitis leads to 

 necrosis of bone and as the result of this to fistulous states,. 



