474 



Journal of Agriculture. 



[8 August, 1907. 



HOCK LAMENESS. 



The most frequent seat of lameness in the hind limb is the region of 

 the hock. It is not only that there is a number of affections of the hock 

 which cause lameness, but also that these are each of common occurrence, 

 and that they all constitute definite unsoundnesses. The principal lame- 

 nesses of the hock are caused bv thoroughpin. bog spavin, bone spavin, 

 and curb. 



Thoroughpin. 



This is an elastic swelling, simulating that of windgall, occurring at 

 the upper part of the hock at the back on each side of the tendinous band 

 known as the hamstring (the tendo-achilles). The swelling is a distension 

 with lubricating fluid (svnovia) of a bursa through which the tendons pass. 

 This bursa extends from the inner to the outer aspect of the tendons, and 

 the swelling can be pushed from one side to the other by pressure of the 

 hand — hence the name "thoroughpin" or " throughpin." (See Fig. 77.) 



Fig. 77. Thoroughpin — the arrow points to tlie enhirgement which in this case is 



slight. 



Causes. — The condition is usually associated with straight hocks, and 

 is more common in draught than in light horses. It is frequently due to 

 sprain of the tendons or of their sheath at this part. Young draught 

 horses with straight hocks, when first put to work, often develop this 

 annoying unsoundness. 



Symptoms. — The lameness is not usually very pronounced, but there is 

 a stiffness of action of the hock which is likelv to wear off with exercise, 

 the cause of which is apparent in the movable swelling. 



Treatment. — The application of pressure on both sides when the horse 

 i.s at rest by means of pads adjusted with straps often results in temporary 

 reduction of the swelling. Daily hand-rubbing is also beneficial. As a 

 blister, to be repeated at weekly intervals for a time, the red mercury 

 ointment (see page 75) or a ten per cent, mixture of oleate of mercurv and 

 sweet oil may be used. 



