Subclavius muscle

In ruminants, the subclavian muscle (Musculus subclavius) is a narrow band which takes origin form the first costal cartilage and blends with the tendon of insertion of the brachiocephalic muscle. 

In the pig and horse, it arises form the second to fourth costal cartilage, passes over the shoulder joint and unites with the aponeurosis of the supraspinous muscle.

In carnivores, the subclavian muscle is not present.

Note:

• The subclavian muscle was formerly called Musculus cleidoscapularis in horses and pigs, and considered as a part of the deep pectoral muscle.
• For R. Barone, the subclavian muscle in humans would equate to a scapular pectoral muscle in animals.
• This muscle should not be confused in ruminants with the fleshy termination of the deep pectoral muscle on the supraspinous muscle