634 



PRINCIPLES OF VETERINARY SURGERY 



by the loss of their radiating canaliculate construction due 

 to anastomosis and distention of the osseous reticula. Some 

 of the Haversian canals are so enlarged that only a few ec- 

 centric lamellae remain and the entire canal is filled with 

 blood. Sometimes a large lacuna filled with a red or yellow- 

 ish substance replaces an entire Haversian system, and com- 

 municates with other systems also similarly destroyed. In 

 the intermediate zone of the long bones, the same enormous 



Fig. 100. 

 Formation of Lacunae by the Disappearance of the Osseous Trabeculse. 



quantity of blood that fills the enlarged Haversian canals 

 is not found, but instead there is perceived large, irregular 

 lacunae, filled with a reddish yellow, semi-transparent sub- 

 stance surrounded by primitive or secondary lamellae in 

 which the osseous cells are replaced by refractive forma- 

 tions. The internal or perimedullary zone presents large, 

 irregular, anastomosing lacunae, having extensions uniting 

 them to the Haversian canals, and separated with well-pre- 

 served osseous tissue. 



