There are four pectoral muscles in the cat: pectoantibranchialis, pectoralis major, pectoralis minor, and xiphihumeralis.

Pectoantibranchialis

Pectoantibranchialis muscle is just one-half inch wide, and is the most superficial in the pectoral muscles. Origin, manubrium of the sternum, Insertion, in a flat tendon on the fascia of the proximal end of the ulna, Action, draws the arm towards the chest.

Pectoralis major

The pectoralis major, also called, pectoralis superficialis, is a broad triangular portion of the pectoralis muscle which is immediately below the pectoantibranchialis. Origin, sternum and median ventral raphe, Insertion, Humerus, Action, draws the arm towards the chest.

Pectoralis minor

The pectoralis minor muscle is a much larger than the Pectoralis major, and is divided into several parts. However, most of its anterior broder is covered by the pectoralis major. Origin, Sternum, Insertion, Humerus, Action, draws the arms towards the chest.

Xiphihumeralis

The most posterior, flat, thin, and long strip of pectoral muscle is the Xiphihumeralis. It is a band of parallel fibers. Origin, xyphoid process of the sternum, Insertion, proximal end of the humerus, Action, draws the arms towards the chest.