1. Trunk Muscles

2. Pectoralis major Origin - sternum, clavicle, & ribs 1 - 6
Insertion - proximal humerus
Action - adducts & flexes humerus; medially rotates arm

3. Rectus abdominus Origin - Pubis
Insertion - sternum & costal cartilage of ribs 5 - 7
Action - flexes vertebral column; increases abdominal pressure

4. External oblique Origin - lower 8 ribs
Insertion - iliac crest of ilium
Action - flexes vertebral column; increases abdominal pressure; aids back muscles with rotation & lateral flexion of the trunk

5. Trapezius
Origin - occipital bone and all cervical and thoracic vertebrae
Insertion - scapula & clavicle
Action - extends neck; adducts and stabilizes scapula

6. Latissimus dorsi Origin - lower spine and iliac crest of ilium
Insertion - proximal humerus
Action - prime mover of arm extension; adducts & medially rotates the arm; brings arm down in power stroke as in striking a blow

7. Deltoid Origin - scapula & clavicle Insertion - humerus
Action - prime mover of arm abduction; aids in flexion, extension, & rotation of the humerus

8. Muscles found only in cats
Pectoantebrachialis
Pectoralis minor
Xiphihumeralis
Deltoid = 3 cat muscles: clavobrachialis, acromiodeltoid, & spinodeltoid
Trapezius = 3 cat muscles: clavotrapezius, acromiotrapezius, & spinotrapezius

9. Trunk Muscles

10. Deep Trunk and Arm Muscles

11. Superficial Muscles: Anterior

12. Superficial Muscles: Posterior