BONES 



43 



on the inflammatory process to throw out healthy bony material 

 sufficient to unite the ends of the bones and form a stiff joint. 



73. Anchylosis, the abnormal consolidation and immobility of 

 a joint. In this case the articular cartilage becomes absorbed or 

 destroyed, and a bony deposit takes its place in and around the 

 damaged joint, the two bones becoming united. Sometimes the 

 disease continues, and breaks out, forming sinuses, which discharge 

 a foetid, irritative matter, and are extremely difficult to deal with, 

 requiring an operation and antiseptic treatment. Generous diet is 

 highly necessary. Old horses are very subject to anchylosis from 

 hard work or rheumatic affection, particularly in the back bones. 

 Great care is therefore necessary in casting these. The knee, hock, 

 fetlock, and pastern joints also on many occasions become fixed, 

 and the flexibility of the limb is interfered with ; but slow work, 

 particularly that on the farm, can be done without pain to the animal, 

 although what may be called mechanical lameness might be present. 

 Anchylosis may, however, arise from other causes, and the joint 

 become fixed. 



74. Necrosis, or death of the bone, resembles mortification in 

 the soft structures. When inflammation of bone is very intense, it 

 may at times terminate in death of the affected part. The hard or 

 compact structure is said to suffer most from necrosis, and when the 

 dead bone is encased in the healthy structure it acts as an irritant, 

 and causes a foetid discharge. I have seen it in the lower jaw, 

 incited by the rough usage of the horse-breaker, where the dead 

 portion, as soon as it became loose enough, was removed, and the 

 part healed. I have removed half of the navicular bone and wing of 

 the coffin bone, also a portion of the shank (metatarsal) bone with 

 success. Immediately the dead portion is removed the discharge 

 ceases, and the place soon heals up. It must be dressed with anti- 

 septics (and nothing is better than a weak solution of hydrochloric 

 acid) and interfered with as little as possible, in order to let it mend. 

 At times the dead portion cannot be got at to remove, and it then 

 becomes sequestrated by healthy bony matter being thrown out, and 

 enveloping the dead portion ; but this is a long process. 



