The Osseous System 341 



matory processes do not long remain confined to one part, but 

 quickly extend to another. Most inflammatory disturbances of 

 bone with which we have to deal in the dog are of a septic nature, 

 and involve the bone proper and medulla. They are acquired either 

 in cases of compound fracture or amputation, or as a result of acute 

 infection as may occur in the course of a severe infectious disease, 

 or in septic thrombosis. But in many cases the cause is wrapt in 

 obscurity. Contusions may favor the occurrence of infection by 

 production of a locus minoris resistentiae to the bacteria which may 

 have gained access to the adjacent soft parts or which may be cir- 

 culating in the blood. The course of the disturbance is similar to 

 that of any other purulent inflammation with migration of leuco- 

 cytes, occlusion of the Haversian canals, arrest of circulation, ne- 

 crosis, and establishment of purulent foci. The latter coalescing, 

 extend along the tract of the marrow and lead to its rapid dis- 

 integration. Pus breaks through the periosteum, burrows along 

 the lines of least resistance, and finally reaches the skin. If the de- 

 structive process is allowed to continue, the entire shaft may be 

 involved, and there is risk of septicemia and pyemia. The disease, 

 when of other than traumatic origin, most frequently attacks the 

 long bones. 



Symptoms and Diagnosis. There is usually some lameness of 

 the affected member. If there is not already a superficial wound 

 when the animal is first seen by the practitioner, a swelling is ob- 

 served in the soft parts covering the affected area, as soon as the 

 pus penetrates the periosteum. The skin assumes a dark-red color 

 and looks "angry." A fistula develops. The tract of the latter, 

 when probed, leads to bone, and this is the chief diagnostic symptom. 



Treatment. This must be energetic and radical. It is useless 

 to treat this disease by means of antiseptic injections. The infected 

 focus must be removed and the only way to accomplish this is to lay 

 the fistula open, expose the medullary canal and scrape away the 

 inflamed marrow. The technic is as follows: The animal being 

 hoppled and given a general anesthetic, and a tourniquet applied 

 to the leg both above and below the wound, the diseased focus is 

 exposed by free incision and dissection down to the bone. Sufficient 



No. 79. Bone Gouge. 



