346 HEALTH AND DISEASE 



18. DISEASES OF THE JOINTS, MUSCLES, 

 TENDONS, AND LIGAMENTS 



(See also \>\>. 279-305) 



DISLOCATIONS 



Dislocation results where the articular ends of bones which enter 

 into the formation of a joint are displaced. 



Bones forming joints are held together by ligaments and muscles. 

 When dislocations occur these are sprained or ruptured to a greater or 

 less degree in the forcible separation of the bones. 



Dislocations may be divided into corigenital, and acquired or acci- 

 dental, in each of which displacement may l^e only partial or complete. 

 In the former it is invariably brought about by some arrest of develop- 

 ment, or injury to parts sustained during gestation. 



" At the period of birth we occasionally meet with congenitally mal- 

 formed limbs, depending either on the flexors or the extensors being 

 too short. It is by far most commonly the flexors which are implicated, 

 thus causing the animal to go on his toes, therel)y distorting the limb or 

 limbs. This distortion may be so sliglit, that in the process of development, 

 if due attention be paid to the shape and position of the feet, no opera- 

 tion, either mechanical or surgical, is required. But should the limb 

 be to a greater extent malformed, it will be necessary to pay even more 

 than usual attention to the feet, and, as soon as time will admit of 

 shoes being placed on them, let it be done. These shoes should have 

 a piece of iron projecting from the toe, from 2 to 3 inches in length, 

 and slightly curved upwards (fig. 380). At the same time the heels must 

 be kept low. 



"The kinds of deformities met with in the growing horse are: first,, 

 congenital and extreme flexure of the pedal bone upon the os corona, 

 (Plate XLII, fig. 1), depending upon the perforans tendon being too short; 

 secondly, permanent flexure of the pastern bones upon the large metacarpal 

 bone (Plate XLII, fig. 2). The perforatus tendon being too short will be 

 found productive of this distortion; sometimes it is also connected with 

 disease of the dense membranous sheath which invests it posteriorly. 

 Depending upon the degree or angle at which the bones are placed, must 

 be our remedial measures. If the distortion be but slight, mechanical 

 means only need be resorted to; if greater, a surgical operation conjoined 

 with some mechanical contrivance will be found to be absolutely necessary. 



" In the second instance, where the extensors are too short the toe 



