es for recovery are much better in high ringbone
than in low ringbone. The classification of Moeller will be followed
here.

[Illustration: Fig. 17--Phalangeal exostoses.]

Symptomatology.--In all forms of incipient ringbone except rachitic,
the first manifestation of its existence, or of injury to the ligaments
in the region of the pastern joint which causes periostitis, or
affections of the articular portions of the proximal inter-phalangeal
joint, is lameness. Lameness which typifies ringbone is of the
supporting-leg variety and by compelling the subject to step from side
to side, marked flinching is observed, especially in periarticular
ringbone; causing the affected animal to turn abruptly on the diseased
member, using it as a pivot, likewise accentuates the manifestation. In
fact, many subjects that exhibit no evidence of locomotory impediment
while walking or trotting in a straight line on a smooth road surface,
will manifest the characteristic form of lameness from ringbone when the
aforementioned side to side movement is performed.

When the manner in which pain is occasioned is considered, it will be
understood why lameness is intermittent in the early stages of this
affection and may even be unnoticed by the driver. An animal may travel
on a smooth road without giving evidence of any inconvenience, but as
soon as a rough and irregular pavement or road surface is reached, will
limp. As the subject is driven farther on level streets the lameness may
disappear. This intermittent type of lameness may continue until there
is developed a large exostosis, or until articular involvement causes so
much distress during locomotion that lameness is constant. On the other
hand, resolution may occur during the stage of periosteal inflammation,
or, an exostosis forms which causes no interference with function.

[Illustration: Fig. 18--Rarefying osteitis in chronic ringbone and
ossification of lateral cartilages.]

Before there is evidence of an exostosis, diagnosis of ringbone is not
easy, for it is then a problem of detecting the presence of a
ligamentous sprain, periostitis, or osteitis. The diagnostician should
take note of local manifestations of hypersensitiveness, or heat if such
exist, and, in addition, other conditions must be excluded before
definite conclusions are possible.

In _articular_ ringbone as soon as there is developed an exostosis, it
occupies a position on the dorsal (anterior) part of the articu