Course.—­Because of the peculiar manner in which the second and third metacarpal bones articulate in young animals, until the bones become ossified and permanently joined, the inflammation which attends the acute stage of this affection, causes lameness.  Later, unless an unusually large exostosis is formed, which may cause a constant irritation due to its size and juxtaposition to the carpus, lameness is discontinued.

Symptomatology.—­Lameness is usually the first manifestation of this disorder, and the thing which characterizes splint lameness is its peculiar intermittence.  There is a mixed form of lameness which may not be in evidence when an affected animal is started on a drive, but which is marked after the subject has gone some distance.  The animal may, however, go lame throughout the whole of a drive and continue to be lame for several days or weeks in some cases.  It is noticeable that lameness is augmented or produced when the subject travels on rough road surfaces and that little or no difficulty is encountered when roads are smooth.

The heavy brachial fascia is inserted in part to the head of the second metacarpal (inner small) bone together with the oblique digital extensor (extensor metacarpi obliquus) and this explains the reason for pain being manifested during extension of the member.

Before there is a visible exostosis, supersensitiveness is readily recognized upon palpation of the parts, if careful comparison is made between the sound and unsound members.  However, frequently splints occur on both forelegs at the same time and in some instances exostoses are several in number upon each member affected.  In some instances, the affection involves the outer splint bone and no evident involvement of the inner one exists.

Treatment.—­At the onset complete rest should be provided and the local application of some good cataplasm is in order.  A stimulating liniment is beneficial when employed several times daily and massage is also quite helpful.  Later, the application of a blistering ointment is good treatment.  The use of the actual cautery stimulates prompt resolution, but there is seldom any resorption of products of inflammation following firing.  Whereas, in cases where other treatment is begun early, there usually follows considerable diminution in the size of the exostosis.  A rest of four or five weeks is necessary and very young animals should not be put to work too soon, if the character of the work is such as to induce a recurrence of the trouble.

Many cases are treated successfully in draft types of animals (where the subjects are not kept at work that occasions serious irritation to the affected parts) by blistering the exostosis repeatedly and allowing the animals to continue in service.  In such cases, it is unreasonable to expect to check the size of the exostosis and, of course, such methods are not employed where lameness causes distress to the subject.