210 



HEALTH AND DISEASE 



Chronic Periostitis. — This form of the disease most commonly 

 presents itself in that affection of the limbs termed sore shins and splints. 



It may, of course, attack any of 

 the bones of the skeleton, but those 

 of the legs are by far the most fre- 

 quently involved. See Sore Shins 

 and Splints. 



Acute Ostitis is comparatively 

 of sekluni occurrence in the horse. 

 Why this should be so it is diffi- 

 cult to say precisely, but the absence 

 of those constitutional conditions 

 which favour its production in 

 man is no doubt in some measure 

 a safeguard against it in our equine 

 patients. The fact that amputation 

 is but seldom resorted to in the 

 horse may also contribute to render 

 liim less frequently the victim of 

 this disease. 



It is mostly observed in the 

 bones of the extremities, and es- 

 pecially those below the knees and 

 hocks. 



Sometimes it is localized or 

 confined to a particular part, or it 

 may involve a large tract, or even 

 the entii'e bone. The writer has 

 seen the whole of the os suffraginis 

 or large pastern bone destroyed, 

 and its remains enclosed in a per- 

 forated shell of bony matter, formed 

 around it by the periosteum (figs. 

 817, 318). It sometimes occurs in 

 the upper and lower jaw-bones. 



Causes. — Acute ostitis is the 

 result of injury inflicted on the bone 

 by external violence, the most severe cases being those in which the 

 bone is penetrated by some .sharp instrument, as when the foot bone is 

 punctured by a nail. The example figured was caused by the foot of 

 the hor.se being brought violently to the ground when attempting to .save 



Fig. 317.— Acute Ostitis 



1, Sequestrum or Slough. 2, 2, Cloacfe or openings 

 for escape of pus ami dead bone. 3, 3, New bone 

 enclosing the sequestrum. 



Fig. 'j\S. — Acute Ostitis 



1, Sequestrum or Slough. 2, New bone enclosing 

 sequestrum. 



