182 PEINOIPLES OF VETEEINAEY SUEGEEY 



the dead piece of bone keeping up the irritation and thus 

 furnishing active material for a purulent discharge. 



Sow do you treat chronic purulent periostitis ? 



This depends on the parts involved. Thus, in alveolar 

 periostitis "with empyema of the maxillary sinus, the sinus is 

 trephined and the offending tooth removed. In other in- 

 stances an incision is made down upon the diseased structures 

 and the necrotic bit of bone removed by curetting, etc. 



Describe chronic fibrous periostitis. 



In this form a fibrous callus is formed, which by its 

 pressure leads to atrophy of the underlying bone. In this 

 instance the inflammation involves the upper layer of the 

 periosteum, which, not being equipped with osteoblasts, can 

 not ossify the products of inflanimation, being a chronic 

 connective tissue proliferation pure and simple. Its most 

 common seat is right on top of the nasal bones, the result 

 of pressure from the noseband of the bridle. 



luflammatiou of the Osseous Tissue. 



Which histological structures does inflammation of the osseous 

 tissue involve f 

 The Haversian canals, spaces and canaliculi. 



What course does osteitis usually tahe ? 

 Almost invariably a chronic course. 



What are the causes of osteitis f 



The most frequent causes are pressure and contusions; 

 specific ones, as tuberculosis, actinomycosis, complicated 

 fractures, the extension of inflammation from some other 

 structure : for instance, from the marrow or periosteum. 



