Scapulothoracic Muscles and Arm (MT)

Name this muscle (action, innervation, origin, insertion)

Trapezius

• Retraction and upward rotation of the scapula, Upper fibers elevate and lower fibers depress and upwardly rotate scapula

• Innervated by Spinal Accessory Nerve (CN XI)

• Originates from superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of C7-T12

• Upper: Inserts at posterior surface of lateral 1/3 of clavicle and acromion

• Middle: acromion and spine of scapula

• Lower: medial 1/3 of scapular spine

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Levator Scapulae

• Elevation and downward rotation of scapula

• Innervated by Dorsal Scapular Nerve

• Originates from transverse processes of C1-C4 vertebrae

• Inserts at superior angle of scapula

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Rhomboid Minor (more superior)

• Elevation, retraction and downward rotation of the scapula

• Innervated by the Dorsal Scapular Nerve

• Originates from spinous processes of C7-T1

• Inserts at vertebral border (root of scap spine to inferior angle)

Rhomboid Major (more inferior)

• Elevation, retraction and downward rotation of the scapula

• Innervated by the Dorsal Scapular Nerve

• Originates from spinous process of T2-T5

• Inserts at vertebral border (root of scap spine to inferior angle)

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Serratus Anterior

• Protraction and upward rotation of the scapula

• Innervated by the Long Thoracic Nerve

• Originates from lateral aspect of upper ribs (8/9)

• Inserts at costal surface of vertebral border of scap

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Pectoralis Minor

• Depression of scapula

• Medial and lateral pectoral nerve

• Originates from anterior aspect of ribs 3-5

• Inserts at the coracoid process

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Pectoralis Major

• Adduction and internal rotation of the arm; clavicular head: flexes arm and sternal head: extends arm from flexed position

• Innervated by Medial and lateral pectoral nerve

• Clavicular head originates from medial clavicle, sternal head originates from sternum and costal cartilage of ribs 1-6

• Inserts at lateral lip of intertubercular groove of the humerus

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Deltoid

• Abduction of arm; Anterior fibers: Flex/IR arm, Posterior fibers: Ext/ER arm

• Innervated by the Axillary Nerve

• Originates from the anterior surface of the lateral 1/3 of the clavicle, acromion process and scapular spine

• Inserts at the deltoid tuberosity of the humerus

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Teres Major

• Adduction, Extension, and Internal Rotation of the arm

• Innervated by the lower subscapular nerve

• Originates from dorsal surface of inferior angle of scapula

• Inserts at the medial lip of the intertubercular groove of humerus

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Latissimus Dorsi

• Adduction, Extension, and Internal Rotation of the arm

• Innervated by the thoracodorsal nerve

• Originates from inferior angle, portions of lower 3 ribs, spinous processes lower 6 thoracic and all lumbar vertebrae, thoracolumbar fascia, iliac crest, sacrum

• Inserts at floor of the intertubercular groove of the humerus

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Supraspinatus

• Abduction of the arm

• Innervated by the suprascapular nerve

• Originates from the supraspinous fossa

• Inserts at the superior facet of the greater tubercle (humerus)

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Infraspinatus

• External rotation of the arm

• Innervated by the suprascapular nerve

• Originates from the infraspinous fossa

• Inserts at the middle facet of the greater tubercle (humerus)

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Teres Minor

• External rotation of the arm

• Innervated by the axillary nerve

• Originates from the upper 2/3 of the axillary border of the scapula

• Inserts at the inferior facet of the greater tubercle (humerus)

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Subscapularis

• Internal rotation of the arm

• Innervated by the upper and lower subscapular nerve

• Originates at the subscapular fossa

• Inserts at the lesser tubercle

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Biceps Brachii

• Flexion and supination of the forearm; Long head (L): flex arm, Short head (R): adduct arm

• Innervated by the musculocutaneous nerve

• Long head originates at supraglenoid tubercle and labrum, Short head at coracoid process

• Inserts at radial tuberosity and bicipital aponeurosis

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Brachialis

• Flexion of forearm

• Innervated by the musculocutaneous nerve

• Originates from the anterior surface of the distal humerus

• Inserts at the coronoid process and tuberosity of the ulna

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Coracobrachialis

• Flexion and adduction of the arm

• Innervated by the musculocutaneous nerve

• Originates from the coracoid process

• Inserts at the middle third of the medial side of the humerus

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Triceps brachii

• Extension of forearm; Long Head extends arm

• Innervated by the radial nerve

• Originates from the infraglenoid tubercle (long head), posterolateral surface of the humerus proximal to radial groove (lateral head), and posterior surface of the humerus distal to radial groove (medial head)

• Inserts at the olecranon process

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Anconeus

• Extension of forearm

• Innervated by the radial nerve

• Originates from lateral epicondyle of the humerus

• Inserts at olecranon process and posterior surface of proximal ulna