234 LAMENESS OF THE HORSE 



illat consider curb as a synovitis having for its seat the synovial 

 bursa which is situated between the superficial flexor tendon 

 (l)erforatus) and the plantar ligament. 



Occurrence. — Certain predisposing factors seem to favor the 

 occurrence of curb. A malformation of tlie inferior part of the 

 tai-sus so that its antero-posterior diameter is considei'ably less 

 than normal is a contributing cause. Such hocks are known as 

 "tied-in." Another fault in conformation is the existence of a 

 weak hock that is set low down on a crooked leg, especially when 

 such a member is heavily muscled at the hip. Given such con- 

 formation in an excitable horse, and curb is usually produced be- 

 fore the subject is old enough for service. It is certain that in 

 cases where conformation is bad, greater strain is put upon the 

 plantar ligament. This structure serves to bind the tibial tarsal 

 (calcis) bone to the metatarsus; traction exerted upon its sum- 

 mit by the tendo Achillis is great when animals run, jump or 

 rear and also at heavy pulling. In animals having curby hocks, 

 sprain is likely to result and curb supervenes. 



Symptomatology. — The characteristic swellins: which marl^-s 

 curl) may develop quickly and lameness occur suddenly or the 

 enlargement comes on gradually and slowly, causing little lame- 

 ness. Lameness is not proportionate to the si7e of the swelling 

 and in all cases whether subacute or chronic, the condition im- 

 proves with rest, but lameness is again manifested upon exertion. 

 A horse which "throws a curb" will go lame until the acute 

 inflammatorv condition subsides and depending upon treatment 

 received and conformation of the hock, this requires from three 

 days to two or three weeks. 



The character of the swelling varies; in some cases it is not 

 larsre but rather dense and lacking in evidence of heat and 

 hvperesthesia ; in other eases there is considerable swellinsr, which 

 is hot and doughy, somewhat painful to the touch but not neces- 

 sarilv productive of much lameness. Tn anv event, whether the 

 swelling or enlargement is bier or little, its location makes it 

 conspicuous when viewed in profile. 



Tn most cases after the acute inflammatory period has passed, 

 lameness is slight, if at all present, and in time no interference 



