Clavobrachialis

The clavobrachialis is found mainly on the dorsal side of the shoulder of the cat down to the ulna's olecranon process. The clavobrachialis and clavotrapezius (more cranial) together make up the brachialis muscle. This muscle pulls the limb forward, extends the shoulder, and depresses and pulls the head and neck laterally.

The clavobrachialis is seen labeled as 1 in this picture (a ventral view).