ions of the Triceps Brachii.
(Triceps Extensor Brachii: Caput Muscles.)

Anatomy.--The triceps brachii is the principal structure which fills
the space between the posterior border of the scapula and the humerus.
The several heads originate for the most part on the border of the
scapula, the deltoid tuberosity of the humerus and the shaft of the
humerus. Insertion of this large muscular mass is effected by means of
several tendons to the olecranon. A synovial bursa is situated
underneath the tendinous attachment of the posterior portion of the
triceps brachii--the long head or caput magnum.

The function of the triceps as a whole is to flex the shoulder joint and
extend the forearm. The triceps brachii is the chief antagonist of the
biceps brachii.

Etiology and Occurrence.--Owing to the exposed position of this
structure, it is not infrequently contused, the result of falls, kicks
and other injuries. The function of the triceps is such that it becomes
strained upon rare occasions when a horse resists confinement of
restraint in such manner that the parts are unduly tensed in
contraction. This sort of resistance may stretch the radial nerve or its
branches in a way that paralysis results. A condition known as "dropped
elbow" is described by Henry Taylor, F.R.C.V.S., in the Veterinary
Record[9], wherein a two-year-old colt while resisting confinement was
so injured.

The triceps group because of its convenient location, constitutes the
site for hypodermic injection of drugs and biologic agents, with some
practitioners; and as a result, more or less inflammation may occur. The
author has observed and treated some twenty cases where an intensely
painful infectious inflammation of the triceps brachii was caused by
the intramuscular injection of a caustic solution by a cruel and
unscrupulous empiric, whose object was to increase his practice.

Symptomatology.--As the triceps brachii is not particularly taxed
during weight bearing in the subject at rest, there may be no unnatural
position assumed during inflammation of the triceps. More or less
swelling and supersensitiveness is always present, however, and great
care and discrimination must be exercised in digital manipulation of the
triceps region because many animals are normally sensitive to palpation
of these parts. It is sometimes difficult to correctly interpret the
true state of conditions because of this peculiarity.

There is always swinging-leg-lameness, whi