596 
SPRAIN OF THE CORONARY JOINT. 
both hind legs. Rheumatism was suspected and treatment directed 
accordingly. One morning the horse was found lying down with the 
left hind fetlock luxated. On being approached to apply a bandage, the 
horse attempted to rise and luxated the other fetlock. On post-mortem, 
the extensor and flexor tendons were found intact, but the synovial 
capsules and lateral ligaments were ruptured. In cases of this kind 
it is almost certain that inflammation or degenerative changes must have 
previously occurred in the lateral ligaments. 
Jolme gives the result of a post-mortem on a horse after luxation of 
the os pedis, where the lower end of the os corona) had been displaced 
backwards and outwards, and lay above the os naviculare. The capsular 
ligament was consequently torn, and the flexor perforans ruptured and 
inflamed. 
Treatment follows general principles. Reposition and control of 
inflammation are, however, very difficult. Anaesthesia is generally 
necessary before reduction can be effected. 
IL—SPRAIN OF THE CORONARY JOINT. 
Whilst luxations of the phalanges are rare, sprain is more common, 
particularly in the coronet-joint. It occurs either from excessive dorsal 
or volar flexion, or forced lateral movement in the joint, caused generally 
by slipping to the side, and consists in violent stretching, sometimes in 
partial rupture of the ligaments. 
Such accidents are favoured by— 
(1) Defective formation of the joints. Small articular sufaces offer 
less secure support, and are generally furnished with weak ligaments. 
This is particularly true of joints which appear narrow when seen from 
in front. 
(2) Faulty position of the limb. The most important of such faults 
is turning the toes outward or inward. If the axes of the joints are not 
perpendicularly under the centre of gravity, unequal stress must be 
thrown on the ligaments every time weight falls on the limb; in addi¬ 
tion, unequal weight being thrown on the inner and outer portions of 
the joints, the gait becomes insecure. 
(3) Narrow hoofs and excessive lowering of the wall. Where one side 
of the wall comes in contact with the ground sooner than the other, the 
load is unevenly distributed, and the articular ligaments are apt to 
suffer. Horses which have worked for a long time under such con¬ 
ditions generally show excessive lengthening of the ligaments, best 
recognised in a position of volar flexion. The immediate causes of 
sprain are slips, falls, or injuries sustained in rising. Such accidents., 
are favoured by irregular pavement, high calkins and heels, narrow¬ 
ness of the chest, and lameness. The condition is therefore commonest 
