158 LAMENESS OF THE HORSE 



entertain upon the suhjeet of navicular disease is. that in by 

 far the greater majority (if not all) of these cases there exists 

 in the animal affected a congenital tendency or predisposition, 

 that, generally speaking, it is the high stepper, the good goer, 

 that becomes the victim to this disease ; and it is a fact well at- 

 tested, that it as frequently develops itself in the feet with wide 

 frogs, bulbous heels, shallow heels, spread flattisli feet, as in the 

 narrow upright feet. . . . T have known foals, born from de- 

 fective parents, in wliicli this condition was so strongly devel- 

 oped, that all men would at once pronounce them affected with 

 navicular disease, a^'-d such lameness was permanent." 



Often both fore feet are affected and this would point toward 

 its being a disease wherein either conformation or congenital 

 tendencies exists. It is rare that hind feet are involved. 



There are many theories regarding the possible exciting causes 

 of navicular disease and, when one has carefully considered the 

 explanations as offered by Peters, INIoller, Branell, Schrader and 

 others, he may conclude that navicular disease is a non-infectu- 

 ous intlammatory affection of the third sesamoid (navicular) 

 bone, deep flexor tendon (perforans) and adjoining structures. 

 "Whether it originates in the flexor tendon or whether the bone 

 is the original part affected, the disease is freciuently met, and 

 of all possible causes, jars and irritation incident to concussion 

 of travel, are pro])ably the princij^al causative agents. 



Symptomatology. — Lameness is the primary indicator and a 

 constant sym])t()m which attends navicular disease wherever 

 much structui-al change aff(M'ts the infirm ])arfs. As the degree 

 of intensity or extent varies, so is there a dissimilarity in the 

 character of the impediment. Incipient cases of bilateral in- 

 volvement are more difficult to diagnose than are unilateral af- 

 fections, particulai'ly when lameness is not marked. There is 

 manifested a sui)i)orting-leg-lameness which varies as to degree 

 in tlie same subject at different times. This may be noticed dur- 

 ing the same ti-ip in an animal tluit is lieing driven. There is 

 a tendency for the subject to stumble and, of course, where the 

 affection is bilateral, there is a stilted gait owing to shortened 

 strides. 



