328 13UKEAU OF A>:iMAL IXDUSIRY. 



FRACTURE OF THE SESAMOID BOXES. 



This lesion hits been considered by veterinarians, erroneoasl}', we 

 think, one of rare occurrence. We believe it to be more frequent 

 than has been supposed. Many observations and careful dissections 

 have convinced us that fractures of these little bones have often been 

 mistaken for specific lesions of the numerous ligaments that are 

 implanted upon their superior and inferior parts, and which have 

 been described as a "giving way" or "breaking down "of these 

 lio-aments. In my post-mortem examinations I have always noted the 

 fact that when the attachments of the ligaments were torn from their 

 bony connections minute fragments of bony structure were also sepa- 

 rated, though we have failed to detect any diseased process of the 

 fibrous tissue composing the ligamentous substance. 



Cause. — From whatever cause this lesion may arise, it can hardly 

 be considered as of a traumatic nature, no external violence having 

 any apparent agency in producing it, and it is our belief that it is due 

 to a peculiar degeneration or softening of the bones themselves, a 

 theory which acquires plausibility from the consideration of the 

 spongy consistencj^ of the sesamoids. The disease is a peculiar one, 

 and the suddenness with which different feet are successively attacked, 

 at short intervals and without any obvious cause, seems to prove the 

 existence of some latent, morbid cause which has been unsuspectedly 

 incubating. It is not peculiar to any particular class of horses, nor 

 to any special season of the year, having fallen under our observation 

 in each of the four seasons. 



Symptoms. — The general fact is reported in the history of a majority 

 of cases that it makes its appearance without premonition in animals 

 wdiich, after enjoying a considerable period of rest, are first exercised 

 or put to work, though in point of fact it may manifest itself while 

 the horse is still idle in his stable. A hypothetical case, in illustra- 

 tion, will explain our theory: An animal which has been at rest in his 

 stable is taken out to work, and it will be presently noticed that there 

 is something unusual in his movement. His gait is changed, and he 

 travels with short, mincing steps, without any of his accustomed ease 

 and freedom. This may continue until his return to the stable, and 

 then, after being placed in his stall, he will be noticed shifting his 

 weight from side to side and from one leg to another, continuing the 

 movement until rupture of the bony structure takes place. But it 

 may happen that the lameness in one or more of the extremities, 

 anterior or posterior, suddenly increases, and it becomes evident that 

 the rupture has taken place in consequence of a misstep or a stumble 

 while the horse is at work. Then, upon coming to a standstill, he will 

 be found with one or more of his toes turned up; he is unable to place 

 the affected foot flat on the ground. The fetlock has dropped and the 

 leg rests upon this part, the skin of which may have remained intact 



