MEMOIR ON TENOTOMY. 
588 
predisposed to contract the deformity of which we are treating, we 
should say the direct causes are those which act immediately upon 
the parts constituting the tendinous region of the cannon. Thus 
wounds — violent contusions of the flexor tendons of the pha- 
langes — strain — laceration of the fibrous bands furnished by the 
posterior carpal and tarsal ligaments to the profundus or per- 
forans muscles — acute or chronic inflammation of the synovial ten- 
dinous sheaths — all may be considered as direct determinant causes 
which sooner or later make the animals suffering from them knuckle 
over. 
The indirect causes, on the other hand, act on the tissues, the 
alteration of which, especially when they are of long standing, will 
bring on contraction of the tendons of the flexor muscles without 
alteration of their substance. Thus wounds penetrating the foot 
of the horse — narrow heels — malformation of the hoof — local 
founder in the sole — navicular disease — periosteal inflammation of 
the pasterns — and, lastly, the development of ringbone ; all may 
indirectly become the cause of the disease we are speaking of, by, 
in a manner, forcing the animal to calculate his weight, and to keep 
the limb constantly flexed or extended out of the perpendicular. 
This unnatural position is speedily followed, bj' a greater or less 
degree of contraction of the flexor muscles of the phalanges. 
When, under the influence of some one of the causes which we 
have mentioned, the fibrous band, or the flexor muscles, that we 
have described, become diseased, a greater or less degree of lame- 
ness is manifested ; when in repose, the animal frequently points 
with the lame leg, or, in other words, extends it forwards or holds 
it half bent. 
No great length of time elapses before a very considerable de- 
gree of swelling is manifested along the whole of the tendinous 
region, and especially towards the superior part: this is often very 
painful on pressure. At this period of the disease the tendinous tis- 
sue, which is the seat of the inflammation, has lost its pearly white hue 
and become of a dullish white, which is sometimes slightly tinged 
with a shade of crimson, arising from an increased development of 
those vessels which even in their natural state are apparent. 
When the inflammation is confined to the fibrous parts of the 
tendinous region, and to the band formed by the carpal and tarsal 
ligaments, the animal has what is commonly termed rigid sinew ; 
and should this pathological alteration in the end require the ope- 
ration of plantar tenotomy, all the conditions necessary to the suc- 
cess of that operation will be found united. If, however, the inflam- 
mation has communicated itself to the surrounding cellular tissues, 
and to the synovial sheaths, which disappear beneath its influence, 
the case becomes much more serious : it is then no longer possible 
