CHAPTER III. 



DISEASES OP JOINTS. 



In this chapter we will consider the diseased conditions to 

 which joints, and the different structures entering into their 

 formation, are liable. 



It may be necessary, first, to remark, that joints are formed 

 by the ends of two or more bones, coated by an elastic sub- 

 stance called gristle or cartilage, their approximated ends 

 being enclosed by a thin membrane or capsular ligament, 

 the inner surface of which secr.etes the synovia, or joint-oil 

 which lubricates the ends of the bones, and prevents fric- 

 tion, and they are held together by means of short, white, 

 glistening bands, called ligaments. 



Before entering into the more complicated diseases of the 

 joints, we will notice first the more simple. 



KNUCKLING OVEE. 



Knuckling, or standing over, is very common in cab and 

 stage horses. It gives the animal an ungainly, worn-out ap- 

 pearance. It may occur on one or both knees, which are 

 bent forward and are very shaky, or the fetlocks may be 

 knuckled forward. Veterinarians differ as to the real na- 

 ture of this condition, or as to the part really at fault. Some 

 suppose that it is from " a relaxed and lengthened state of 

 the extensor muscles ; " others " of the ligamentous tissue 

 at the anterior part of the joint ; " others " an inordinate 



