there is shortening of the anterior portion of the stride. There being
loss of function of the triceps brachii, it is impossible for the
subject to straighten the leg in the normal position for supporting
weight; therefore, any attempt to bear weight results in further
flexion of the affected member and the animal will fall if the body is
not suddenly caught up with the sound leg.

Differential Diagnosis.--In making examination of these cases, one can
exclude fracture by absence of crepitation and usually, also, swelling
is absent in radial paralysis. In a typical case of radial paralysis,
the affected leg can sustain its normal share of weight if placed in
position, that is, if the carpal joint is extended in such manner that
the leg is positioned as in its normal weight-bearing attitude. In
brachial paralysis, whether due to fracture of the first rib or to other
serious injury, it is impossible for the subject to support weight with
the affected member even when it is passively placed in position.

No difficulty is ordinarily experienced in differentiating radial
paralysis from muscular injuries to the triceps; yet, in some cases of
"dropped elbow," it is necessary to observe the progress of the case for
ten days or two weeks before one can positively establish a diagnosis.

Quoting Merillat[12]: "When, after four weeks, there is no
amelioration of the paralysis, the muscles have atrophied, and the
patient has become emaciated from pain and discomfort, the
diagnosis of brachial paralysis with fracture of the first rib may
then be announced."

Prognosis.--When no complete paralysis of the brachial plexus or no
fracture of the first rib exists, the majority of cases recover