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Anterior Deltoid
- Origin-Lateral 1/3 of clavicle
- Insertion-Deltoid Tuberosity of humerus
- Actions-Shoulder flexion, Hor. Add, IR of shoulder
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Middle Deltoid
- Origin-Acromion of scapula, lateral surface
- Insertion-Deltoid tuberosity of humerus
- Actions-shoulder abd to 90 degrees
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Posterior Deltoid
- Origin-Spine of scapula
- Insertion-Deltoid tuberosity of humerus
- Actions-shoulder extension, hor. abd, ER of shoulder, scaption of humerus
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Supraspinatus
- Origin-supraspinous fossa of scapula
- Insertion-Greater tubercle of humerus (superior facet)
- Actions-shoulder abd, scaption of humerus, stabilize and depress head of humerus in glenoid fossa
- Part of the Rotator Cuffs
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Infraspinatus
- Origin-infraspinous fossa of scapula
- Insertion-Greater tubercle of humerus (middle facet)
- Actions-ER of shoulder, shoulder extension, stabilize and depress head of scapula in glenoid fossa of humerus
- Part of the Rotator Cuffs
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Subscapularis
- Origin-subscapular fossa of scapula
- Insertion-lesser tubercle of humerus
- Actions-IR of shoulder, shoulder add, stabilize and depress head of scapula in glenoid fossa of humerus
- Part of the Rotator Cuffs
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Teres Minor
- Origin-Upper 2/3 of axillary border of scapula
- Insertion-Greater tubercle of humerus (inferior facet)
- Actions-ER of shoulder, shoulder extension, stabilize and depress head of scapula in glenoid fossa of humerus
- Part of the Rotator Cuffs
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Teres Major
- Origin-inferior angle of scapula (dorsal surface), lower 1/3 of axillary border of scapula
- Insertion-Medial lip of intertubercle grove of humerus
- Actions-shoulder extension, IR of shoulder, shoulder add
- Joins with Latissimus dorsi to form posterior border of the axilla
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Latissimus Dorsi
- Origin-thoracolumbar aponeurosis, T7-T12 spinous processes, sacrum, iliac crest, lower 3 to 4 ribs, inferior angle of scapula
- Insertion-intertubercular groove of humerus
- Actions-shoulder extension, IR of shoulder, shoulder add, IR of scapula, assists depression of scapula
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Coracobrachialis
- Origin-coracoid process of scapula
- Insertion-middle 1/3 of medial surface of humeral shaft (opposite of deltiod tuberosity but larger area)
- Actions-shoulder flexion, shoulder add
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Pectoralis Major
- Origin-clavicular head-medial half of clavicle, sternocostal head-sternum, cartilages of superior 6 ribs, aponeurosis of external oblique muscle
- Insertion-lateral lip of intertubercular groove of humerus
- Actions-hor. add., shoulder IR, clavicular head-shoulder flexion, sternocostal head-shoulder extension, assists anterior tilt of scapula
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Serratus Anterior
- Origin-lateral surface of upper 8 ribs
- Insertion-vertebral border of scapula-anterior surface
- Actions-scapular abd (protraction), lateral (upward) rotation of scapula, stabilizes scapula against chest wall, depression of scapula
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Middle Trapezius
- Origin-C7-T3 spinous processes
- Insertion-Spine of scapula
- Actions-add (retraction) of scapula
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Lower Trapezius
- Origin-T4-T12 spinous processes
- Insertion-root of spine of scapula
- Actions-depression of scapula, lateral (upward) rotation of scapula
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Rhomboids
- Origin-C7-T5 spinous processes
- Insertion-vertebral border of scapula, root of spine of scapula
- Actions-add (retraction) of scapula, medial (upward) rotation of scapule
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