POSTERIOR MEMBER. 



273 



They may for a long time remain compatible with the liberty of the movements. 

 They (the articular especially) lame the animal only in cases of abundant hyper- 

 secretion of synovia and excessive tension on the surrounding tissues. Their 

 parietes, in long-standing cases, become thickened and calcified in places, restrain- 

 ing greatly the tarsal movements. When the calcification is very extensive, it 

 constitutes a false anchylosis of the articulation, which renders rapid locomotion 

 absolutely impossible. 



e. The Bones.— The osseous blemishes in the region of the hock have 

 received different names. They are: curb, spavin, and Jarde. 



1st. Curb.— Curb (Fig. 84, B, and Fig. 85, A) is a periostitis of the infero- 

 internal tuberosity of the tibia, which is developed under the influence of external 

 violence or excessive strain of the articulation. It is characterized by the forma- 

 tion of osseous layers, which ai-e disposed in regular strata upon the tibial tuber- 

 osity, over the surface covered by the attachment of the internal lateral ligament. 



Fig. 84. 



Fig. 85. 



This formation offers a longitudinal groove in which the tendon of the oblique 

 flexor of the phalanges glides and manifests itself externally by a curve, more 

 pronounced than in a normal state, when this face is viewed from in front, behind, 

 or obliquely. At the beginning, it is often difficult of recognition from its feeble 

 dimensions, which render the comparison of the two hocks necessary. Unless 

 they are both blemished, it is generally easy to determine the presence of such a 

 neoplasm, for it is exceptional that the two enlargements should be absolutely 

 identical in relation to their form and volume. Curb only occasioas lameness 

 during its formation ; when it is once developed, the lameness disappears. 

 Nevertheless, there are some which from the volume which they attain cover up 

 the margin of the tibial articular surfaces and interfere, more or less, with the 

 freedom of the movements ; in such cases they are all the more grave, as they 

 are rebellious to all means of treatment. 



2d. Spavin. — The term spavin should be reserved to denote a periostitis 

 at the lower and internal part of the hock (Fig. 84 and Fig. 86, A). It involves 



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