70(3 
DISEASES OF THE LEG. 
to the metatarsus, and as the flexor metatarsi muscle itself is powerless 
to make up for this deficiency, the cannon bone is no longer flexed on the 
limb, but hangs inertly, and all the lower joints of the limb follow suit 
or are slightly flexed. That portion of the limb below the hock is not 
properly advanced, whilst the relaxation of the tendon favours excessive 
flexion of the stifle-joint. This want of harmony in the function of both 
joints produces an uncertain 
movement of the limb, which 
may give the impression of 
a broken bone, and has been 
so interpreted by some. The 
absence of fracture, however, 
is at once shown by the fact 
that the limb can still support 
weight. The serious syrup* 
toms apparent during move* 
ment disappear when the 
animal is at rest. In rupture 
of the flexor metatarsi, the 
function of its tendon is in 
abeyance ; while its anta¬ 
gonist, ix., the tendo Acliillis, 
is unopposed, appears re¬ 
laxed, and when the limb 
is relieved of weight and 
extended lies flaccid. This 
appearance is very charac¬ 
teristic, and only occurs in 
two other conditions, viz., 
rupture of the tendo Achillis 
and fracture of the tibia. It 
most marked when the 
Iug. 260.—-Showing the mechanism of the hock and 
stifle joints. The tendons of the flexor metatarsi 
and gastrocnemius muscles unite the hones forming 
the joints in such a way that they are unable to 
move independently. 1, Superficial division of the 
flexor metatarsi muscle; 2, 2', and 2", flexor 
perforatus ; 3, 
IS 
hock is excessively extended, 
as, for instance, by the farrier 
lifting the limb to remove the 
shoe. In recent cases the 
anterior surface of the tibia is sometimes slightly cedematous, in others 
gastrocnemius tendon. 
absolutely nothing abnormal can be seen. Severe swelling with pain 
on pressure over the course of the flexor metatarsi is quite exceptional, 
the muscles being clothed in a strong fascia. 
Course. The affection is naturally of sudden onset, and at once 
produces a peculiar lameness. As weight can still he placed on the leg, 
and the ends of the tendon retract comparatively little, union is seldom 
