BOG-SPAVIN. 
7l7 
joint of an ox and evacuated some fibrino-purulent fluid. Healing 
occurred under permanent irrigation. 
To prevent excessive granulation in the bend of the hock, the animal 
should be tied up short, and every precaution taken to limit movement 
of the hock-joint: the granulations themselves are treated on general 
principles. 
IY.—BOG-SPAYIN. 
Bog-spavin consists in excessive distension of the capsule of the true 
hock-joint. The capsular ligament and synovial membrane are attached 
above close to the articular surface of the tibia, below to that of the 
astragalus. Anteriorly and inwardly the sac presents a small dilatation, 
posteriorly and externally a larger one, which Franck says often com¬ 
municates with the sheath of the flexor pedis perforans tendon at the 
inner side of the joint. Disease of this tendon sheath, however, seldom 
extends to the hock-joint, and vice versa. 
Distension of the capsule of the true hock-joint is commonest in young 
horses with upright hocks, but is also frequent in old stallions and 
pregnant animals. It is generally due to chronic synovitis, brought on 
by severe exertion; occasionally it follows acute synovitis. Chronic 
suppuration in this joint sometimes accompanies pyaemic inflammation 
of the urachus in foals, and is almost always fatal. 
The most noticeable symptom is the presence of a fluctuating swelling, 
which may be thrust backwards and forwards. 
There is seldom acute inflammation, and therefore lameness is rare. 
Distension of the capsule is only dangerous to life when due to acute 
synovitis or umbilical phlebitis. In well-developed cases the animal 
may show lameness after severe exertion. 
Treatment must follow general principles. Recent painful and inflamed 
swellings are treated by cold applications, and later by blistering. As 
tiring only diminishes the swelling, and always leaves visible scars, it 
merely substitutes one blemish for another; nevertheless, Stockfleth 
recommends it. If resorted to, needle firing is the preferable method. 
In young horses, with moderately developed bog-spavin, repeated 
painting with tincture of iodine or massage may diminish swelling, but 
seldom removes it completely. In foals treatment is rarely of permanent 
value, and relapses often occur. 
Caution is required in operating surgically. Removal of contents by 
Pravaz's syringe or a slender trochar is occasionally followed by benefit, 
and injection of iodine may be tried. In most cases the operation must 
be repeated several times, at intervals of four to six weeks, to be of 
service. Evacuation by Pravaz s syringe, washing out with 1 in 1,000 
