378 FRACTURE OF THE SESAMOID BONES OF OFF FORE-LEG, 
was resting against the flexor tendons and on the broken surface of the 
sesamoid bones. There was a good deal of extravasated blood around 
the joint. 
I may add that the horse was galloping on a perfectly level course, and 
nothing could be seen as being likely to have caused the accident. He 
had been previously fired on both fore legs, and during the last season 
he had gone a little stale on them. 
I send the bones, &c., for your examination. 
I am, &c., 
F. Blakewat. 
To G. W. Varnell, Esq. 
I found the bones to be fractured in a transverse direction, 
a little above their middle; and, in addition, I noticed that 
the upper part of the inner one was broken into three or four 
pieces. The capsular ligament was much torn, and the 
outer branch of the superior sesamoidal ligament was also 
lacerated. The inner branch, however, had not suffered from 
recent injury, but was much thickened from previous disease 
evidently of long standing. In attempting to elucidate the 
most prominent features of this case, it will be necessary to 
discuss two or three points. In the first place it may be 
asked, what was the immediate cause of the fracture? Did it 
take place from over-tension, or from a blow produced by the 
hind foot during the act of progression? Upon reflection, I 
think the former was the most probable cause. The flexor 
tendons and common integument would prevent, to some 
extent, sufficient force being applied to the bones in question 
to cause fracture. If, then, it occurred, as I think it did, from 
over-tension, it may again be asked, if there were any predis¬ 
posing causes favorable to such a lesion ? I am inclined to think 
there were, as the fractured bones did not appear to be so com¬ 
pact as these bones are usually found—their structure seemed 
more spongy and fragile—at least such was my impression. 
This being the case, I think w T e may fairly admit that they 
were incapable of resisting the same amount of force which 
they would have done had their structure been of normal den¬ 
sity and toughness. Bones are tough, by virtue of the animal 
matter they contain; and hard, through the earthy material 
in their composition. Let there be a deficiency of either of 
these normal constituents, and they become liable to be in¬ 
jured, through the common physical forces they are exposed 
to. I may next observe, that the superior sesamoidal liga¬ 
ment was diseased to a great extent. The outer branch was 
partially torn through, while the inner was much thickened 
from disease of long standing. This ligament, in its normal 
condition, yields more than ordinary ligamentous tissue when 
weight is thrown upon it, and it contains in its structure a 
