DISEASES OF THE HOCK. 



the character of the disease, especially it synovia is being discharged. 

 There is always more or less swelling, which extends round the joint, 

 and both upwards and downwards ; though soft at first, it later 

 becomes hard and resistant. The distension of the tibio-tarsal 

 capsule is often masked by the periarticular swelling. From the 

 first lameness is severe, and is exhibited both when the limb is being 

 advanced and when weight is placed on it (mixed lameness). Fever 

 is present in the purulent or septic variety of disease, and periarticular 

 abscesses nearly always form. 



The disease can only be mistaken for severe subfascial cellulitis 



(see kL Wounds and Injuries of 

 the Lower Thigh and Leg "), 

 but as this exhibits all the above- 

 described symptoms, some time 

 may elapse before the diagnosis 

 becomes assured. If the con- 

 dition improves after the ab- 

 scesses break, and especially if 

 lameness decreases, the joint 

 may still prove intact, but im- 

 provement is sometimes only 

 apparent, and due to laminitis 

 in the other foot, from the 

 animal continually standing. 

 Increased pulsation in the meta- 

 tarsal arteries points to the 

 occurrence of laminitis and dis- 

 placement of the os pedis. 



Fractures of the malleoli of 

 the tibia and of the astragalus 

 cause similar symptoms, and, 

 unless accompanied by crepitation, are very difficult to diagnose. 



Injuries to the front of the hock are also difficult to treat, especially 

 when large flaps of skin are destroyed. The unavoidable movement 

 of this joint in horses irritates the wound, causing active granulation, 

 which is sometimes impossible to repress. Fig. 533 shows such a 

 condition, photographed from nature. 



Course and prognosis. The course depends principally on whether 

 the parts remain aseptic. If they do not, recovery is highly 

 improbable, and oxen should be slaughtered before they have lost 

 much condition. The prognosis is therefore doubtful in all cases 

 of inflammation caused by external injury or by metastasis, though 



Fig. 533. — Exuberant granulation in front 



of the hock. 



