446 DISEASES OF THE HORSE’S FOOT 
D. DISLOCATIONS.” 
The firm and rigid manner in which the bones of the 
pedal articulation are held together renders dislocation of 
this joint an exceedingly rare occurrence, and then it is 
only liable to happen under the operation of great force. 
In the literature to our hand we have only been successful 
in discovering one reported instance, and, strange to say, 
in this, a well-marked case, the cause was altogether 
obscure. We quote the case at the end of this section. 
WN 
> N 
2S 
< 
K 
Fig. 165.—D1aGRam sHOWING THE COURSE TAKEN BY THE NEEDLE 
WHEN SETONING THE FRoG. 
\ 
XN 
\ 
wh 
This is shown by the dotted curved line a, b. 
1, The navicular bone ; 2, the plantar cushion ; 3, the os pedis ; 4, the 
perforans tendon. 
A partial dislocation of this articulation is the condition 
met with in ‘ Buttress Foot.’ In this case the fracture of 
the pyramidal process, and the consequent lengthening of 
the tendon of the extensor pedis, allows the os corone to 
occupy upon the articulatory surface of the os pedis a more 
backward position than normally it should. 
It is quite probable, too, that slight lesions of the other 
restraining ligaments and tendons of the articulation may 
