RUPTURE OF THE FLEXOR TENDONS AND SUSPENSORY LIGAMENT. 569 
Rupture of fasciculi occur in almost all cases of inflammation of the 
flexor tendons produced by severe strains. 
Symptoms. Rupture is at once followed by lameness. Either no 
weight can be borne by the limb, or if weight is placed on it for a 
moment the affected joint is abnormally flexed; the symptom, however, 
is less marked in rupture of the perforatus tendon. In consequence of 
the dorsal flexion of the coronet-joint, the toe of the foot is directed 
upwards. Rupture of the superior sesamoidal ligament produces 
abnormal dorsal extension of the fetlock (fig. 210), but the toe retains its 
normal position. The same is true of ruptures of the inferior sesamoidal 
ligaments. In rupture of the flexor 
perforans, all three phalangeal joints 
show abnormal dorsal flexion, the 
hoof sometimes only touching the 
ground at the heels. Unless swell¬ 
ing has become pronounced the rup¬ 
ture may be detected by palpation. 
The degree of pain varies greatly; 
usually it is slight. 
Course. Ruptures of the flexor 
tendons unite regularly and com¬ 
pletely, provided— 
(1) The ends of the tendons are 
not too far apart, and Fig. 210.— Rupture of the superior sesamoidal 
suspensory ligament (from a photograph). 
(2) Rupture has occurred outside 
the region of the tendon sheath. Ruptures within the tendon sheath 
unite exceedingly slowly, and only incompletely, because here the para- 
tendineum (connective tissue surrounding the tendon), which mainly 
contributes to union, is wanting. The extent to which the ends of the 
tendons are displaced may be estimated from the change in position of 
the fetlock. Under favourable circumstances, rupture of the flexor per¬ 
forans or perforatus unites in six weeks,Though two to three months may 
elapse before the animal is fit for use. A race-horse which had suffered 
rupture of the suspensory ligament, with fracture of a sesamoid, in one fore 
limb was no better after six weeks. It was killed, and on post-mortem 
it was found that though union had begun, yet there was no visible callus 
formation between the displaced fragments of the sesamoid bone. 
Ruptures of one or other insertion, of the suspensory ligament unite in 
from six to eight weeks, usually without leaving any lameness. The 
condition becomes grave when the rupture occurs over the sesamoid 
bones. Where rupture of the tendons is accompanied by other 
diseased processes like acute or chronic navicular disease or necrosis, the 
prognosis is quite hopeless. 
