The deltoid muscles are just lateral to the
Trapezius muscles. Anatomically, there are only two deltoids in the
cat, and that si the Acromiodeltoid, and the Spinodeltoid. However, the
Clavobranchialis, is now also considered as a deltoid, so as to conform
to
Human Anatomy standards. It is therefore called Clavodeltoid.
Acromiodeltoid
It is the shortest Deltoid muscle. It lies lateral to the clavodeltoid, and
in a more husky cat, this can only be seen by lifting the clavodeltoid. Origin,
Acromion process, Insertion, deltoid ridge, Action, Raises and Rotates the
humerus outward
Spinodeltoid
A stout and short muscle lying posterior to the acromiodeltoid. It lies along
the lower border of the scapula, and it passes through the upper arm, across the
upper end of muscles of the upper arm. Origin, spine of the scapula, Insertion,
deltoid ridge, Action, raises and rotates the humerus outward.
The clavodeltoids are the branchial (arm) continuation of the clavotrapezius.
It is the muscle on the anterior surface of the shoulder and anterior to the
pectoantibranchialis. The clavotrapezius and the clavodeltoid (clavobranchialis)
are sometimes considered by anatomists as consisting one muscle, which si the
cephalobranchial (literally, head to arm). The clavicle is embedded under this
muscle. Origin, Clavicle and Fibers of the Clavotrapezius, Insertion, Ulna,
Action, flexor of the forearm.