EING-BONES. 



287 



Eing-bone must not be confounded with what is termed side- 

 bone ; the first is a bone disease, the second a disease of fibro- 

 cartilage. 



Ring-bones, whether high or low, 

 vary in size ; but the degree of lame- 

 ness does not depend upon the mere 

 size of the new formation. An animal 

 may be very lame, indeed, with but 

 little osseous deposit; and another 

 may show but little lameness, with a 

 very large ring-bone. 



Very often the segment of the ring 

 is defective, and the deposit may ap- 

 pear only on one surface of the limb, 

 or on both sides without any promi- 

 nence in the front. When at the 

 sides, they do not cause the same de- 

 gree of lameness as when the front is 

 involved. 



Eing-bones are not the cause, but 

 the result of disease, being the effect 

 of an inflammation originating in the 

 extremities of the bones, or synovial 

 membranes of the articulations which 

 they involve. As a rule, they are the 

 result of ostitis, commencing in the 

 cancellated structure of the bones, the 

 areolae of which first became filled 

 with an organizable lymph, convertible 

 into bony material, as already de- 

 scribed. — (See Ostitis, p. 151.) During 

 the progress of the inflammation, the 

 articular cartilage and laminal layer 

 of the end of the bones become re- 

 moved by absorption, while external 

 to the joint active deposition of bony 

 material is going on, for the purpose 

 of repairing the damage within. 



In some instances the disease may commence at the inferior 

 extremity of the os suffraginis, and gradually involve the 



Fig. 46. — Lowering-bone. 



Fig. 47. 



