312 PARTICULAR LAMENESSES. 



swelling, sufficiently large to allow the complete removal of 

 the fluid ; and it should remain open for some days. No fear 

 need be entertained, although signs of pain and fever may ensue, 

 as an open bursa is not so serious as an open joint. 



After the sac is emptied, a weak solution of sulphate of zinc 

 or dilute tincture of iodine may be injected ; the walls of the 

 sac brought into apposition by firm but careful bandaging ; a 

 flannel bandage, owing to its elasticity, being the best of all. 



CAPPED HOCK. 



The gastrocnemius internus muscle terminates about half-w^ay 

 down the tibia in a strong tendon ; it is at first within the tendon 

 of the gastrocnemius externus ; winds round its side ; then 

 surmounts it, and, on reaching the point of the os calcis, forms a 

 cap, giving off slips of insertion from each side to the bone. A 

 large synovial bursa exists between the tendons here, and is 

 one of the seats of capped hock. 



There are two forms of capped hock — the synovial and the 

 serous. 



Synovial Capped Hock appears as a tense fluctuating swelling, 

 situated upon both sides of the point of the hock ; the tendon, 

 being posterior to the bursa, prevents the swelling of the internus 

 from bulging backwards. It is an unsoundness, causing lame- 

 ness, and sometimes the formation of abscesses from caries or 

 necrosis of the summit of the os calcis. — (See Photo-lithograph, 

 Plate I., Fig. 3.) 



The Serous Capped Hock, a serous abscess caused by pressure 

 or violence, is situated in the areolar tissue, between the tendon 

 of the gastrocnemius internus and skin. 



It is not an unsoundness, if not causing lameness, and arises 

 generally from the horse striking the point of his hock against 

 some hard substance. It very often indicates a kicker, either in 

 harness or in the stable, is unsightly when large, and depreciates 

 the value of the animal. 



Displacement of Tendon of Gastrocnemius Internus. — Professor 

 Dick used to relate that he had met with cases of what he called 

 dislocation of the tendon of the gastrocnemius internus, and that 

 the tendon had been torn from its attachment to the os calcis. 

 He said it always fell to the outside, thereby not untwisting itself 



