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DADD'S VETERINARY MEDICINE AND SURGERY. 



Thorough-pin. 



The seat of thorough-pin is between the popliteous (fig. 2) and 

 the point of the hock, near where the tendon is severed, as shown 

 in the accompanying engraving. The disease is called thorough- 

 pin, simply because the fluid contained in the bursal sac can be 

 squeezed from one side to the other. 



YIEW OF SOME OF THE DEEP-SEATED MUSCLES IN THE BEGION OF THE HOCK AK» STIFLE. 



Explanation.— 1, Popliteous ; 2, Flexor pedis accessorius ; 3, Flexor metatarsi magnus ; 

 4, The tendon, common both to the flexor metatarsi and extensor pedis ; 5. The groove 

 in which the extensor plays. 



Symptoms. — The disease is similar to bog spavin and wind-galls ; 

 namely, enlargement of a synovial sac. It seldom if ever lames 

 a horse, yet, when large, is apt to interfere with the free action of 

 the joint, 



In former years it was customary to open thorough-pins by 

 means of a lancet, in view of evacuating the fluid; but many fatal 



