more frequently affected are the supra- and infrascapularis
(antea- and posteaspinatus) muscles. But in some cases the triceps group
is involved; however, this occurs in unusual and chronic affections. No
doubt, these chronic cases are due to suspended innervation and are not
to be classed with the ordinary case of atrophy of the abductor muscles
of the humerus (supra- and infraspinatus) as in the usual case of
"sweeny."

Occurrence.--Shoulder atrophy such as the general practitioner
commonly meets with, is an affection, more often seen in young animals
and it seems to be due to injuries of various kinds which contuse the
muscles of the shoulder. Ill-fitting collars and pulling in a manner
that there occurs side draft with unusual strain on the muscles of one
side of the neck and shoulder, seem to be the more frequent causes of
this trouble. Blows such as are occasioned by kicks and falls frequently
result in atrophy of shoulder muscles.

Course.--In some cases a rapidly progressive atrophy characterizes the
case and lameness and atrophy appear at about the same time. The
affection in such instances does not recover spontaneously but
constitutes a condition which requires prompt and rational treatment so
that function may be fully restored to the parts involved.

Occasionally one may observe cases where there is but slight atrophy;
where the disease progresses slowly and atrophy is not extensive or
marked. In vigorous young animals that are left to run at pasture when
so mildly affected, spontaneous recovery occurs.

Symptomatology.--Lameness is the first manifestation of shoulder
atrophy, and in many cases where lameness is slight, the veterinarian
may fail to discover the exact nature of the trouble if he is not very
proficient as a diagnostician of lameness or if he is careless in taking
into consideration obtainable history, age of the subject, etc. Because
of the fact that the average layman believes that practically every case
of fore-leg lameness wherein it is not obvious that the cause is
elsewhere, is due to a shoulder affection of some kind, we may be too
hasty in giving the client assurance that no "sweeny" exists. In some of
these cases where a diagnosis of "shoulder lameness" has been made and
the client has been assured that no sweeny exists, the patient is
returned in about a week and there is then marked atrophy of one or both
of the spinatus muscles.

A mixed type of lameness characterizes this af