portions of the joint have an attachment around the
distal end of the radius and another at the proximal end of the
metacarpal bones.

[Illustration: Fig. 13--Carpal exostosis in aged horse.]

Etiology and Occurrence.--Puncture wounds of any kind may serve to
perforate the joint capsule and such traumatisms are occasioned by
falls, kicks and in various ways in runaway accidents, and open carpal
joint may follow.

Symptomatology.--The pathognomonic symptoms of the existence of an
open joint is the exposure to view of articular surfaces of bones or
noting the escape of synovia from the joint capsule. As has been
previously referred to, there always exists a peculiar suspension of
carpal flexion in all cases of carpitis.

Non-infective wounds which may cause open joint are not necessarily
productive of an active carpitis--a synovitis may be the extent of the
disturbance. Unlike synovitis, which may characterize a non-infectious
penetrative wound of the capsular ligament, septic arthritis which may
supervene is a very painful inflammatory disturbance. It is
characterized by all of the symptoms which attend the case of open joint
and synovitis plus the obvious manifestation of great pain. There is an
elevation of temperature of from two to five degrees above normal;
circulation is accelerated; the pulse is bounding; respiration is
hurried; there is an expression of pain as indicated by the physiognomy;
and because of rapid erosive changes of cartilages which take place,
there is soon so much of the articulation destroyed that death is
inevitable. Death is usually due to generalization of the arthritic
infection.

[Illustration: Fig. 14--Exostosis of carpus resultant from carpitis.]

[Illustration: Fig. 15--Distal end of radius. Illustrating the effects
of chronic carpitis.]

In the meanwhile, if the character of the infectious material is not so
virulent, the disease will take on a slower course and the subject may
experience laminitis from supporting weight upon the sound member, or
because of continued recumbency, decubital gangrene and emaciation
sometimes cause death. If the subject does not soon succumb, it is
compelled to undergo days or even weeks of unnecessary suffering, and
too often in such cases, it is later deemed advisable to destroy the
animal because of the cost of continuing treatment until the horse is
serviceable. Therefore, it is evident that when such joints as the
carpus or tarsus are open and