Muscle Action & Attachment

Deltoid

• Abduct arm; flex and extend arm; medially and laterally rotate arm

• Origin: Clavicle; acromion; spine of scapula

• Insertion: Deltoid tuberosity

Supraspinatus

• Abduct arm

• Origin: Supraspinous fossa

• Insertion: Greater tubercle

Infraspinatus

• Extend and adduct arm

• Origin: Infraspinous fossa

• Insertion: Greater tubercle

Coracobrachialis

• Flex and adduct arm

• Origin: Coracoid process

• Insertion: Medial surface of humerus shaft

Subscapularis

• Medially rotate arm

• Origin: Subscapular fossa

• Insertion: Lesser tubercle

Teres major

• Extend and adduct arm

• Origin: Posterior surface of scapula

• Insertion: Intertubercular sulcus of humerus

Teres minor

• Extend and adduct arm

• Origin: Lateral border of scapula

• Insertion: Greater tubercle

Biceps brachii

• Flex and supinate forearm

• Origin: Coracoid process and supraglenoid tubercle

• Insertion: Radial tuberosity

Brachialis

• Flex forearm

• Origin: Anterior surface of distal humerus

• Insertion: Coronoid process of ulna

Triceps brachii

• Extend forearm

• Origin: Infraglenoid tubercle; posterior shaft of humerus; distal radial groove

• Insertion: Olecranon

Brachioradialis

• Flex forearm

• Origin: Lateral supracondylar ridge

• Insertion: Styloid process of radius

Pronator quadratus

• Pronate forearm

• Origin: Distal portion of anterior ulna shaft

• Insertion: Distal surface of anterior radius

Pronator teres

• Pronate forearm

• Origin: Medial epicondyle of humerus; coronoid process of ulna

• Insertion: Lateral radius

Supinator

• Supinate forearm

• Origin: Lateral epicondyle of humerus; proximal ulna

• Insertion: Proximal end of radius

Flexor carpi radialis

• Flex and abduct wrist

• Origin: Medial epicondyle of humerus

• Insertion: Base of 2^nd and 3^rd metacarpals

Flexor carpi ulnaris

• Flex and adduct wrist

• Origin: Medial epicondyle; olecranon; posterior surface of ulna

• Insertion: Pisiform and hamate bones; base of 5^th metacarpal

Extensor carpi radialis brevis

• Extend and abduct wrist

• Origin: Lateral epicondyle of humerus

• Insertion: Base of 3^rd metacarpal

Extensor carpi radialis longus

• Extend and abduct wrist

• Origin: Lateral supracondylar ridge of humerus

• Insertion: Base of 2^nd metacarpal

Extensor carpi ulnaris

• Extend and adduct wrist

• Origin: Lateral epicondyle of humerus; posterior border of ulna

• Insertion: Base of 5^th metacarpal

Palmaris longus

• Flex wrist

• Origin: Medial epicondyle of humerus

• Insertion: Palmar aponeurosis; skin and fascia of palm

Flexor digitorum profundus

• Flex wrist and fingers

• Origin: Coronoid process; anteromedial surface of ulna; interosseous membrane

• Insertion: Distal phalanges of fingers 2-5

Flexor digitorum superficialis

• Flex wrist and fingers 2-5

• Origin: Medial epicondyle of humerus; coronoid process of ulna; shaft of radius

• Insertion: Middle phalanges of fingers 2-5

Extensor digitorum

• Extend fingers and wrist

• Origin: Lateral epicondyle of humerus

• Insertion: Phalanges of fingers 2-5

Flexor pollicis brevis

• Flex thumb

• Origin: Flexor retinaculum; trapezium

• Insertion: Lateral base of proximal phalanx of thumb

Flexor pollcis longus

• Flex thumb

• Origin: Anterior surface of radius; interosseous membrane

• Insertion: Distal phalanx of thumb

Extensor pollicis brevis

• Extend thumb

• Origin: Dorsal shaft of radius and ulna; interosseous membrane

• Insertion: Base of proximal phalanx of thumb

Extensor pollicis longus

• Extend thumb

• Origin: Dorsal shaft of radius and ulna; interosseous membrane

• Insertion: Base of distal phalanx of thumb

Abductor pollicis brevis

• Abduct thumb

• Origin: Flexor retinaculum; carpal bones

• Insertion: Lateral base of proximal phalanx of thumb

Abductor pollicis longus

• Abduct and extend thumb; abduct wrist

• Origin: Posterior surface of radius and ulna; interosseous membrane

• Insertion: Base of first metacarpal; trapezium