Overview
Veterinary nomenclature distinguishes two groups, the superficial pectorals (mm. pectorales superficiales) and the deep pectoral (m. pectoralis profundus). Classic feline anatomy texts describe four muscles in the cat, from superficial to deep:
- Pectoantebrachialis (m. pectoantebrachialis): a thin band from the manubrium to the antebrachial fascia.
- Pectoralis major: from the cranial sternum to the humerus.
- Pectoralis minor: deep to the former and, despite its name, larger in the cat.
- Xiphihumeralis (m. xiphihumeralis): the most caudal, from the xiphoid process to the humerus.
The first two correspond to the superficial pectorals and the last two to the deep pectoral.
Origin
- Superficial pectorals: manubrium and first sternebrae.
- Deep pectoral: body of the sternum and xiphoid process.
Insertion
- Superficial pectorals: cranial surface of the humerus; the pectoantebrachialis continues into the antebrachial fascia.
- Deep pectoral: proximal humerus.
Action
Adduct the thoracic limb. The deep pectoral also draws the limb caudally and, with the limb planted, pulls the trunk cranially.
Innervation
Cranial and caudal pectoral nerves (nn. pectorales) from the brachial plexus.