SrRAIN OF THE SACK SIJN'EWS. 117 



militate against tlie free action of the tendons, and thus 

 requiring a greater degree of exertion to keep up progressive 

 motion. This will be the case, even with the best horse, 

 otherwise well formed, and who has a complete degree of 

 muscular development ; which bj a continuance of the 

 pressure and action must strain the tendons. But this is 

 not all : when the back tendons are thus bound down, they 

 are squeezed into a more oblique direction, consequently it 

 requires a greater force to make the muscles act, and fatigue 

 is induced in a shorter time, and it is almost always accom- 

 panied by a sprain. In short, it is one of the worst defects 

 incidental to the horse. 



SPRAIN OF THE BACK SINEWS. 



The back tendons are enclosed in a sheath of thick 

 cellular substance, which not only protects them from 

 injury, but also keeps them in their proper situation. To 

 prevent friction, a mucous fluid intervenes between the 

 sheath and the tendon. When the horse has been over- 

 exerted, or over-Avorked, the tendon presses upon the delicate* 

 membrane with which the sheath is lined, and induces 

 inflammation. This creates the secretion and discharge of 

 a different fluid, which becomes coagulated, and the conse- 

 quence is, that adhesions are formed between the sheath and 

 tendons, which render the motion of the limb more diflicult 

 and cause pain during action. Long-continued action will 

 also sometimes rupture some of the fibres with which the 

 tendons are bound. This is what has been termed a sprain 

 of the back sinew, and when this takes place to a greater 

 extent, the horse is said to have hrohen doiun. So that, in 

 point of fact, there is no rupture of the tendon itself, as it 

 cannot be sprained, not being elastic or capable of extension. 



Symptoms. — It will be seen that during every movement 



