Lesson
Shoulder/Arm Muscles
| Action- | Abduction & ——————– Horizontal Abduction | Adduction & ———————— Horizontal Adduction | Flexion | Extension | Lateral/ External Rotation | Medial/ Internal Rotation |
| Muscles | -Supraspinatus (initiates) -Deltoid (middle) ——————– -Deltoid (middle & posterior) -Infraspinatus -Teres Minor -Teres Major & Latissimus Dorsi | Gravity when unresisted If resisted: -Pectoralis Major (sterno- costal) -Latissimus Dorsi -Teres Major -Coracobrachialis & subscapularis, Triceps bracii (long) & Teres Minor (from abduction) ———————— -Pectoralis Major -Deltoid (anterior) -Coracobrachialis -Biceps (short) | -Deltoid (anterior) -Pectoralis Major (clavicular) -Biceps brachii (short head; long head not active when forearm/elbow do not move) -Coracobrachialis | Gravity when unresisted If resisted: -Latissimus Dorsi Teres Major Pectoralis Major (sterno- costal-from flexion) -Deltoid (posterior)& -Triceps (long head) | -Infraspinatus –Teres Minor -Deltoid (posterior) | -Subscapularis –Teres Major -Latissimus Dorsi -Pectoralis Major -Deltoid (anterior) |
Note: underlined muscles are prime movers, the rest are assistants