331 



CHAPTER XVI. 



Serous Cysts. 



general remarks capped hock capped elbow i^erous ttst 



3s(ear the withers. 



General Remarks. 



A SEKOTTS cyst is a cavity formed by an effusion of serous fluid into con- 

 nective tissue, the fibres of which, by the consequent pressure, are squeezed 

 together and thus form the membranous wall of the cyst, which subse- 

 quently becomes thickened by new growth of fibrous tissue. A cyst of this 

 kind may be defined as a cavity resulting from the abnormal distension 

 of a natural space, suxrounded by a more or less distinct wall, and filled 

 with fluid or semi-solid matter. These enlargements are specially liable to 

 occur, as a result of inflammation, immediately underneath those portions 

 of the skin which cover bony prominences ; because, in these positions, the 

 extent of the seat of injury being narrowly limited between the bone and 

 the skin, a closely confined effusion is more likely to take place, than in 

 a part surrounded by soft structures. 



Serous fluid (p. 13), which is the watery fluid found on opening 

 a blister, often accumulates -at th-e point of the hock, or at the 

 back of the elbow, causing these parts to become " capped," as a 

 result of injury. Unlike synovia, serous fluid generally becomes 

 quickly organised into fibrous tissue. 



These enlargements, though unsightly, rarely cause uneasiness 

 to the horse. They may be treated boldly by surgical means, as 

 they are well removed from any important structures. If the 

 case be of long standing and 'the seat of injury be on .the surface 

 of the body, the distended condition of the skin which covers the 

 part, will persist after the subsidence or removal of the en- 

 largement. 



Capped Hock. 



Ordinary capped hock is a serous cyst situated at the point of 

 the hock (Fig. 137), between the cap of the perforatus tendon and 

 the skin (Fig. 28). It is usually the result of blows, which ai'e 



