523 
AN ESSAY ON CHRONIC PODOTROCHOL1TIS. 
thence it passes the flexor tendons, and from them reaches the 
sesamoid bones, which latter soon become carious. In whichever 
of these organs it be that the inflammation first arises, the fibres 
of the perforans, and sometimes those of the perforatus also, 
become detached, as in podotrocholitis, throughout the whole of 
the surface in contact with the large sesamoid bones : sooner or 
later this effect of the disease is inevitable. In consequence, the 
tendons contract an adherence to each other; the bursa mucosa, 
the synovial capsule, the ligaments, &c. become thickened and 
indurated*. 
This disease, like podotrocholitis, is slow in its progress : the 
lameness accompanying each is developed by similar anormal 
movements; hence it is easy to confound these two affections. 
The way to distinguish them is to take into account the local 
symptoms. At the commencement of inflammation of the sesa- 
moid trochlea, the heat is concentrated either on the posterior 
surface of the pastern, or round about the articulation. If the foot 
be lifted, and that portion of the tendons covering the large sesa- 
moid bones are firmly compressed, while at the same time the 
pastern is alternately flexed and extended, the animal will evince 
evident pain. The alterations of the bursse mucosae of the syno- 
vial capsule, and of the ligaments in the ulterior stages of the dis- 
ease, leave no room for further uncertainty. 
V. — EXOSTOSIS OF THE CANNON BONE AND WINDGALLS OF THE 
TENDON. 
During the development of the disease, before the formation of 
those tumours which subsequently characterise the pathological 
lesions of which we are now speaking, exostosis of the cannon 
bone and windgalls of the tendon, have, as far as regards the na- 
ture of the lameness, considerable analogy with podotrocholitis. 
Slow of formation, these lesions escape observation for a long time, 
and present a singularly complicated diagnostic. 
VI. — NEUROMES. 
These tumours of the nerves, which Rigott has the merit of hav- 
ing first pointed out, are the result of local inflammation accompanied 
* I met with one case where the caries of the large sesamoid bones pre- 
sented deep holes : they were likewise united with the posterior surface of 
the cannon bone, by means of a bony exudation. The horse knuckled over 
to that degree that the articular surface of the metacarpal had lost all its 
relations with that of the pastern bone ; it protruded over this latter, and 
supported itself against the synovial capsule, which was thickened and 
indurated. 
f Recueil de M4d6cine V4t4rinaire, vol. vi, p. 624. 
