SPRAINS OF TENDONS,-—NERF-FERURE.--TENOSITIS, 307 
For a long time, in classical language, “ powerful and repeated efforts 
of locomotion ” were mentioned as causes of those injuries. The mode 
of action of these causes has been closely studied of late by Barrier and 
' Siedamgrotzky.. With the assistance of instantaneous chromo-photographs 
taken in series, these authors have given a new pathology of the altera- 
tions of the disease. It is summarized as follows: 
Let us suppose a leg, in which the metacarpal and phalangeal levers 
flex normally: at the moment when the leg in motion comes to the 
ground, the phalanges are in the long axis of the canon; as soon as the 
resting of the foot to the ground takes place, the phalangeal lever, formed 
by the first and second pasterns, operates a movement of flexion upon the 
immobile hoof, which has for effect to bring closer to each other the 
semi-lunar crest and the sesamoid pulley, and also to relax the perforans. 
A slight flexion of the first phalange also takes place on the second, con- 
tributing to the relaxation of the perforatus and of the perforans. The 
fetlock, no longer supported by the tendons, drops, the sesamoid pulley 
slides over the anterior face of the deep flexor, and at this moment the 
suspensory ligament is alone preventing the dropping of the fetlock back- 
wards. If the reactions are powerful, or if the suspensory ligament is 
diseased, it may tear. When a slight downward motion takes place, the 
perforatus comes to the assistance of the suspensor; and, for Barrier and 
Siedamgrotzky, the lesions of the superficial flexor takes place at the first 
step. of the rest of the foot on the ground. On the contrary, the perfor- 
ans, more relaxed, is seldom lacerated. But at the time preceding the 
raising of the foot, when the leg is in hyperextension, the angle of the fet- 
lock is bent forward, the phalanges become upright, the canon is oblique 
from forward backward, the perforans is powerfully stretched by the pro- 
jecting behind of the sesamoid and glenoid pulleys, and it is the less 
resisting—the reénforcing band (la bride)—which generally gives way. 
It is shown that, according to the new theory, the suspensory ligament 
and the perforatus are liable to injuries at the beginning of the period of 
rest of the foot, while it is the perforans and its reénforcing bands, the 
lateral ligament of the phalangeal joints, the digital ligaments, which are 
threatened at the end of the rest, when the leg ready to leave the ground 
is in hyperextension. Barrier has specially insisted upon the secondary 
“ nerf-férures.” He has shown that the false ankylosis of the first and 
second interphalangeal articulations predispose to the lesions of the per- 
forans, of the carpal and tarsal bands and of the perforatus ; with Petit, 
he has observed that the chronic great sesamoideal synovitis, in prevent- 
ing the functions of the pedal pulley, brings on atrophical lesions of the 
perforans, well accused, and, by that alone, predisposes to the disease of 
the perforatus. In fact, the lesions of the carpal band occur frequently 
