muscle and terminating in the infraspinatus (postea-spinatus) muscle.

Etiology and Occurrence.--As the result of direct injury to this nerve
by contusion such as may be received in runaway accidents, collar
bruises, especially collar bruises in young horses that are not
accustomed to pulling and that walk in a manner to cause side draft,
injury to the nerve occurs, and partial or complete paralysis
supervenes. Some writers state that it may be produced by confining an
animal in recumbency, with the casting harness. The common cause of
paralysis or paresis of this nerve in cases such as one observes in
country practice, is bruises from the collar in colts that are put to
heavy farm work or where ill fitting collars are used.

Symptomatology.--With partial or complete suspension of function of
the suprascapular nerve there results enervation of the supraspinatus
and infraspinatus muscles. Since these muscles act as external lateral
ligaments of the scapulohumeral joint, when they are incapacitated,
there naturally follows more or less abduction of the shoulder when
weight is borne.

In extreme cases, as soon as the ailing animal is caused to support
weight with the affected member, the joint is suddenly thrown outward in
a manner that the average layman at once concludes that there must be
scapulohumeral luxation, and the veterinarian receives a call to see a
case wherein the "shoulder is out of place." There exists, however, no
luxation in such cases.

If serious injury is done the nerve so that it undergoes degenerative
changes, there will result atrophy of the muscles that derive their
nerve supply from the suprascapular nerve.