PRINCIPLES OF VETERINARY SURGERY 



631 



marrow is red and the medullary canal is enlarged. In 

 some cases the marrow is yellowish. On the surface of the 

 section may be seen reddish or grey dots, more or less 

 large, in which the osseous substance has been displaced by 

 a soft tissue. In the centre of the short bones the osseous 

 substance has undergone great changes. It is softened and 

 formed into a large cavity filled with a sanguineous pulp, 

 which, pressed between the finger, reveals the presence of 

 bony splinters — the remains of the osseous lamellae. The 

 areolae of the epiphyses are considerably enlarged and filled 

 with a sanguinolent marrow. A fresh bone when macer- 

 ated and exposed to the air loses three-quarters of its weight. 



Fig. 99. 



Section through the Head at the Fourth Molar Showing the Narrowing of 



the Cavities and Sinuses. 



A fresh tibia that weighed 735 grams, after maceration and 

 desiccation, was reduced to 250 grams. A humerus 

 weighed 270 grams, a scapula 155 grams and a femur 320 

 grams. In flat bones like the scapula, a very pronounced 

 hypertrophy may often be observed along the entire 

 acromion spine. Similar alterations are seen in the ischial 

 tuberosity and iliac spine. The ribs of horses that have re- 

 mained permanently recumbent during the last days of their 

 existence are often found fractured. Sometimes one rib alone 

 is the seat of numerous fractures. The ribs, the vertebrae 



