68 PRINCIPLES OF VETERINARY SURGERY 



absorption. When located in vital organs the systemic 

 disturbances will vary with the location. They may be fatal, 

 grave or trivial. 



Necrosis of bone in animals is seen only in the traumatic 

 form. It is never spontaneous nor diffused. The necrosis 

 of bone encountered in veterinary subjects is always of a 

 circumscribed and rather trivial character. Injuries that 

 destroy the periosteum, or circumscribed inflammations that 

 impair its osteogenic function are always the exciting causes. 

 Lesions of sufficient magnitude to cause an extensive 

 necrosis in the bones of animals usually prove fatal from 

 other causes before the necrotic process has had time to 

 evolve. The special necroses of animals are; ,(i) necrosis 

 of the superficial bones from accidental wounds that impli- 

 cate the periosteum ; (2) necrosis of the retrossal and basilar 

 apophyses of the os pedis from suppurating corns; (3) necro- 

 sis of the solar surface of the os pedis from nail pricks ; (4) 

 necrosis of the inferior maxilla in the interdental space from 

 bit pressure ; (5) necrosis of the superior extremities of the 

 superior spinous apophyses of the dorsal vertebrae from 

 fistulse of the withers; (6) and necrosis of the anterior angle 

 of the ilium from prolonged decumbency or violence. It will 

 be seen that all of the conditions are traumatic, rather trivial, 

 and limited in extent. In this form of local death a given 

 section of bone is deprived of its nutrition by the loss of the 

 fibrous covering — the periosteum — upon which its life de- 

 pends. The extent is always subordinate to the area stripped 

 of its periosteum by disease or injury, and owing to the fact 

 the bone tissue receives nutrition from within, the necrosis 

 is never deep. Like gangrene of soft tissues deprived of 

 their nutrient blood supply, the bone tissue stripped of its 

 periosteum, separates from the contiguous, living bone after 

 the formation of a distinct line of demarcation, and then is 

 past of! in the form of ^ somewhat irregular sequestrum, 



