254 LAMENESS OF THE HORSE 



digital extensor is the only extensor of the phalanges of the 

 pelvic limb, its rupture or division coiistitutes a troublesome 

 condition, which in some eases does not readily respond to treat- 

 ment. 



Rupture of this tendon may occur during work on rough and 

 uneven roads, particularly in range horses that are ridden over 

 ground that is burrowed by gophers or prairie dogs; in such 

 cases, horses are apt to suddenly and violently turn the foot 

 in position of volar flexion, thereby causing undue strain to the 

 digital extensor and its rupture sometimes follows. In foals 

 of one or two days of age, this tendon is sometimes found parted 

 or ruptured and the condition may be bilateral. 



As the result of accidents, the digital extensor may be divided 

 and when the wound becomes contaminated, as it does because 

 of the marked volar flexion (knuckling) which occurs during the 

 course of this affection, regeneration of tissue is checked and re- 

 covery is tardy. 



Symptomatology. — There is no interference with ability to 

 sustain weight in such cases, when the foot is placed in normal 

 position; but immediately upon attempting to walk, the toe is 

 dragged, and if weight is borne with the affected member, it 

 comes upon the anterior face of the fetlock. The flexors are 

 not antagonized and if there be an open wound the parts soon 

 become contaminated; or, in rupture, if animals travel about 

 very much, there soon occurs necrosis of the tissues of the 

 anterior fetlock region and the condition is rendered in- 

 curable. Cases are reported of animals that have suffered rup- 

 ture of the long digital extensor and the subjects learned to 

 throw the member forward during extension, substituting for 

 the extensor tendon the pendulum-like momentum which the foot 

 affords when so employed; and a walking and even a trotting 

 pace was possible without doing injury to the fetlock region. 



Where a subcutaneous division exists as in rupture, the di- 

 vided ends of the tendon may ])e definitely recognized liy palpa- 

 tion. 



Treatment. — Subjects are l)est put in slings and k('i)t so con- 

 fined until regeneration of tendinous structures has been com- 



