OSTEO POROSIS. 
205 
The anterior surface of the phalanges are concave; the pyramidal 
process of the os pedis is prominent. If the limb be used the 
weight falls chiefly on the heel. The toe has a tendency to turn 
upward. In this state the animal cannot stand long; however, 
the diagnosis can be made by manipulating the foot while he is 
lying down. Inflammation around the seat of rupture becomes 
very severe. Suppuration is established and the breaking through 
of the skin takes place at the fetlock. A finger can be introduced 
into the orifice which will come in contact with the coffin bone, 
that is if the separation be of the flexor pedis perforans tendon. I 
will here state that the tendon itself never ruptures but separates 
at the insertion, often tearing a piece of bone with it to which it is 
attached. 
Next in importance is the separation of the flexor pedis perfo- 
rantus. This is not as frequent as the former; when it does tear, 
it tears at its insertion, taking with it the upper postero lateral 
margin of os cornea. This naturally does not allow the phalanges 
to drop entirely, although the displacement is easily perceptible. 
In such instances suppuration does not follow, but lameness and 
inflammation is intense. 
Fracture of the os calsis is an occasional accident, that is com¬ 
plicated with osteo porosis, caused by over-exertion, in falling, or 
whilst struggling to rise. The symptoms are quite obvious. The 
point of the hock joint appears flattened, enlarged and painful 
upon pressure. Upon careful examination mobility is felt. The 
limb from the hock drops downward and forward, the hoof rest¬ 
ing in close proximity with the forefoot of the same side, forming 
an angle of 45°, 
Fractures of the sessamoid bones is not an uncommon occur¬ 
rence in this disease. If it occur, it usually takes place at the 
inferior third of the bones, causing the ankle to drop partially and 
the inferior sesamoidean ligament loses its hold. 
It sometimes happens that horses afflicted with this disease 
while walking on a level street, by simple slip or misstep, can 
fracture the external angle of the illium. 
One case of fractured metatarsus of a Shetland pony came 
under my observation, caused by a liorseshoer, while attempting 
