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ENLARGEMENT OF SYNOVIAL CAVITIES IN FORE LIMB. 
unless they can be kept aseptic, as purulent synovitis generally results, 
and eventually proves fatal. 
ENLARGEMENT OF ARTICULAR AND TENDINOUS 
SYNOVIAL CAVITIES IN THE FORE LIMB. 
In the fore limb several of the joint cavities and tendon sheaths are so 
situate that distension is not visible externally. This is the case in the 
shoulder and elbow. On the other hand, other joints, tendon sheaths, 
and bursae, when excessively distended with synovia, form swellings or 
“ galls.” To prevent repetition the most important will here be 
collectively dealt with. We may distinguish three varieties:— 
(A) Distension of joints; (B) Distension of the sheaths of flexor 
tendons ; (C) Distension of the sheaths of extensor tendons. 
(A) Distension of articular synovial sacs. 
1. Of the knee. Though the construction of the knee is unfavourable 
to the production of “galls,” yet in working-horses distension of the 
capsular ligament lying between the radius and upper row of carpal 
bones is occasionally seen. This constitutes a knee gall, and either 
appears as a roundish swelling, divided into several parts by the 
extensor tendons on the front of the knee, or occasionally as a tumour 
the size of a hen’s egg, lying on the outer surface of the limb, behind 
the radius and just over the pisiform bone. 
2. Fetlock galls. These consist of roundish swellings between the 
metacarpus and suspensory ligament, caused by distension of the 
synovial membrane of the fetlock-joint. They are divided into two 
parts, are seldom larger than a duck’s egg, and extend towards the 
front of the fetlock, appearing on either side of the extensor pedis. 
When the foot is lifted they may disappear, but immediately height 
is placed on the limb they return. In exceptional cases they appear 
at the posterior part of the fetlock-joint and close below it. Hoffmann 
says they are particularly noticeable when the fetlock is upright. 
(The reader is advised to refer to “Diseases of the Tendons and 
Tendon Sheaths in the Tarsal and Metatarsal Regions,” and to study 
it in connection with the present section. It contains some illustrations 
throwing light on conditions here described.) 
8. Of the hoof. These are of rare occurrence. They appear above the 
coionaiy margin at the toe as tense, painful swellings as large as 
hens’ eggs; their real nature is often unrecognised. Frick has seen a 
number, and has satisfied himself of their true character by post-mortem 
examination. 
(B) Distension of the sheaths of flexor tendons. 
It is now geneially allowed that distension of the sheaths of flexors 
