CHAPTER VII. 
BURSAL ENLARGEMENTS. 
Bog Spavin, Windgalls. Thoroughpin. Capped Hock and Elbow. 
THOROUGHPIN. 
THOROUGHPIN is a bursal enlargement, which appears as a swelling on the 
lower and lateral aspect of the thigh, at the upper and back part of the hock. 
It is due to a swollen condition of the sheath, which envelopes the flexor 
perforans tendon ; and this may be owing to disease of the tendon itself, 
or to disease of ihe sheath. If a thoroughpin be pressed upon, it may be 
made to move from one side to the other. In size these bursal enlargements 
differ very much, varying from that of a pigeon’s egg to a child’s head. It 
has been noticed that they are more commonly found in animals with short 
vertical hocks; and that heredity has much to do with the predisposition, 
which some horses have to this form of disease. Thoroughpin constitutes 
unsoundness, although fortunately it is in almost all cases a curable affection. 
Generally it is consequent on sprain of the tendon, sustained by moving a 
heavy weight ; though occasionally it is due to an over-secretion of fluid in 
the sac. In the latter case, when it is termed dropsical, it is as a rule more 
amenable to treatment, than when following a severe sprain. 
It is our custom, in treating thoroughpin, to order the attendant to direct 
a flow of water from a hose, for half-an-hour three times daily, on to the 
swollen hock, and to apply a well-fitting spring truss, which is easily procured 
at a small expense. This method of treatment is nearly always successful ; 
but the length of time it must be persevered with, varies greatly. When it is 
not efficacious in causing disappearance of the thoroughpin, it is our practice 
to blister the swelling with equal parts of ointment of biniodide of mercury 
and of cantharides. From the first in all cases it is advisable to apply a 
high-heeled shoe. Should this not prove successful, firing with the stripe-iron 
will always prove efficacious in reducing the swelling. Some writers 
recommend the application of the ointment of iodine, or of the liniment of 
this drug, in preference to the cold water treatment. The method of treating 
thoroughpin, by evacuating the sac by means of a puncturing needle, applied 
carefully under the skin, we do not recommend, as it is, to say the least, 
dangerous, and in many hands has proved fatal. Just recently we 
have had under treatment a thoroughpin nearly as large asa child’s head. 
This disappeared after firing, and has since shown no signs of recurrence. 
