Deltoid muscle

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 huskier 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.

Clavodeltoid (Clavobranchialis; Cleidobranchialis)

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.