AN ESSAY ON CHRONIC PODOTROCHOLITIS. 
407 
anatomical structure and functions of the parts which constitute 
the seat of chronic podotrocholitis. These parts are the navicular 
bone, the flexor perforans tendon, the bursal mucous membrane, 
the ligaments of the navicular bone, the heels, and the frog. 
To the pulley-like adjustment between the posterior surface of 
the navicular bone and that portion of the flexor tendon which 
glides over it, he gives the- name of trochlea of the foot ; the trochlea 
extending forward to the place of insertion of the tendon into the 
coffin bone. 
PATHOLOGY OF CHRONIC PODOTROCHOLITIS. 
General Characters. — Chronic podotrocholitis, maladie navicu- 
laire of the French, navicular disease of the English, chronische 
Hufgelenklcehme of the Germans, is a very serious affection, ex- 
clusively peculiar to the horse, and frequently attacking that 
animal. Blood horses, whose hoofs are upright and contracted, are 
particularly subject to it : it developes itself chiefly in the fore feet 
of saddle horses, and appears to have a peculiar predilection for 
the right foot. 
Opinions vary with respect to the seat of the disease. Some 
authors place it on the posterior surface of the navicular bone, 
among these is Hausemann, who says* “ An inflammation fre- 
quently arises in the articulation of the foot, which creates lame- 
ness ; it is of the same nature as that which engenders ringbone ; 
it arises on the posterior surface of the navicular bone.” Others, 
on the contrary, believe that the affection first of all invades the 
anterior surface of the tendon. According to Turnert, it commences 
in the bursa mucosa, and in that portion of it which lies in contact 
with the anterior surface of the tendon. My own observations 
have proved to me that neither the navicular nor the bursa is the 
invariable seat of chronic podotrocholitis : it is as likely to arise in 
one tissue as in the other. I have found the bursal membrane in- 
flamed while the navicular, both in the recent state and after mace- 
ration, betrayed no morbid alteration. I have afterwards seen 
cases in which the disease had evidently commenced in the navi- 
cular bone. When this latter is primitively attacked, the podo- 
trocholitis develops itself slowly and insensibly ; but when the 
former is affected first, the evolution of the disease progresses with 
much greater rapidity. It is, nevertheless, worthy of remark, that 
where the navicular is the one attacked, the inflammation is not 
long in reaching the bursal membrane, either by sympathy or 
* Ueber Entztindung, Hanover, 1837, p. 8. 
f The Veterinarian, 1829, p. 59: 1830, p. 36. 
