180 PEINCIPLES OP TETEEINARY SURGERY 



How do you treat these cases ? 



Rest to the parts ; wheii possible, warm moist applica- 

 iions, blisters. 



.Describe chronic ossifying periostitis. 



In this form the products of inflammation become ossi- 

 £ed, showing that the inflammatory process mainly involves 

 the deeper layer of the periosteum. — that is, the osteogenous 

 layer inhabited by the osteoblasts ; the form is a sequel of 

 acute aseptic periostitis playing such an important r61e in the 

 callus formation of a simple fracture. 



What are the causes of chronic ossifying periostitis ? 

 Repeated traumatic irritation of the periosteum. 



What are the symptoms of this form of periostitis ? 



In due time a bony growth appears, variously known as 

 •osteophyte, exostosis ; previous to the full development of 

 this bony deposit there is pain on palpation, more or less 

 •doughy swelling, possibly lameness, etc. 



Which hones most commonly undergo chronic ossifying 

 periostitis ? 



The bone most commonly affected is the metacarpus of 

 the horse ; here the exostosis is termed a splint and appears 

 almost invariably between the small and large metacarpal 

 bones on the internal face of the shin bone ; the exostosis 

 about the tarsus is known as spavin. Animals with certaia 

 malpositions of the limbs are predisposed to a chronic ossify- 

 ing periostitis, leading to a bony growth termed a " periar- 

 -ticular ringbone." In these cases the periosteum is con- 

 tinuously irritated by being tugged upon by the ligaments of 

 the joint, the result of the faulty position of the hoof. A 

 similar explanation holds good in splint formations. In 



