Symptomatology.—­The characteristic swelling which marks curb may develop quickly and lameness occur suddenly or the enlargement comes on gradually and slowly, causing little lameness.  Lameness is not proportionate to the size of the swelling and in all cases whether subacute or chronic, the condition improves with rest, but lameness is again manifested upon exertion.  A horse which “throws a curb” will go lame until the acute inflammatory 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 large but rather dense and lacking in evidence of heat and hyperesthesia; in other cases there is considerable swelling, which is hot and doughy, somewhat painful to the touch but not necessarily productive of much lameness.  In any event, whether the swelling or enlargement is big or little, its location makes it conspicuous when viewed in profile.

In most cases after the acute inflammatory period has passed, lameness is slight, if at all present, and in time no interference with the subject’s usefulness is occasioned because of the curb, but the animals often remain blemished—­complete resorption of inflammatory products being unusual when much disturbance has existed.

Treatment.—­The handling of curb during the acute inflammatory stage is along the same lines as in sprain—­local applications of cold and heat.  Subjects must be kept quiet until all inflammation has subsided, for there are no cases wherein a little brisk exercise is more likely to cause a recurrence of lameness before recovery is complete than in curb.  Vesication is in order in a week or ten days after the affection has set in; in old stubborn cases that have resisted ordinary treatment for a few months, the use of the actual cautery (line firing) is to be recommended.

[Illustration:  Fig. 55—­Spavin.]

Spavin. (Bone Spavin.)

This term is applied to an affection of the tarsus which is usually characterized by the existence of an exostosis on the mesial and inferior portion of the hock.  There is also included under this name, articular inflammation wherein no external evidence is shown.  Spavin lameness has long been recognized and much has been written upon this subject.  Since authorities are agreed that most cases of lameness in the hind leg are due to hock affection, and because the majority of cases of lameness which have the tarsal region as the seat of trouble are instances of spavin lameness, this disease merits all the attention it has received.

Etiology and Occurrence.—­Causes may well be classified as predisposing and exciting, for there are many etiologic factors to be reckoned with in spavin, some of which are widely different in nature.