Triceps Brachii
Origin: Long head- inferior margin of glenoid cavity; lateral head- posterior humerus; medial head- distal radial groove on posterior humerus
Insertion: Olecranon process of ulna
Action: Powerful forearm extensor; antagonist of forearm flexors (brachialis
Anconeus
Origin: Lateral epicondyle of humerus
Insertion: Lateral aspect of olecranon process of ulna
Action: Abducts ulna during forearm pronation; extends elbow
Innervation: Radial nerve
Biceps Brachii
Origin: Short head: coracoid process; tendon of long head runs in intertubercular sulcus and within capsule of shoulder joint
Insertion: Radial tuberosity
Action: Flexion (powerful) of elbow and supination of forearm; "it turns the corkscrew and pulls the
Brachioradialis
Origin: Lateral ridge at distal end of humerus
Insertion: Base of styloid process of radius
Action: Synergist in forearm flexion
Innervation: Radial nerve
Brachialis
Origin: Distal portion of anterior humerus
Insertion: Coronoid process of ulna
Action: A major flexor of forearm
Innervation: Musculocutaneous nerve, also radial nerve
Pronator Teres
Origin: Medial epicondyle of humerus and coronoid process of ulna
Insertion: Midshaft of radius
Action: Acts synergistically with pronator quadratus to pronate forearm; weak elbow flexor
Innervation: Median nerve
Flexor Carpi Radialis
Origin: Medial epicondyle of humerus
Insertion: base of metacarpals 2 and 3
Action: Powerful flexor of wrist; abducts hand
Innervation: Median nerve
Palmaris Longus
Origin: Medial epicondyle of humerus
Insertion: Palmar aponeurosis; skin and fascia of palm
Action: Flexes wrist (weak); tenses skin and fascia of palm
Innervation: Median nerve, C6 and C7
Flexor Carpi Ulnaris
Origin: Medial epicondyle of humerus and olecranon process and posterior surface of ulna
Insertion: Base of metacarpal 5; pisiform and hamate bones
Action: Powerful flexor of wrist; adducts hand
Innervation: Ulnar nerve
Flexor Digitorum Superficialis
Origin: Medial epicondyle of humerus, coronoid process of ulna, and shaft of radius
Insertion: Middle phalanges of fingers 2-5
Action: Flexes wrist and middle phalanges of fingers 2-5
Innervation: Median nerve (C7, C8, and T1)
Flexor Pollicis Longus
Origin: Anterior surface of radius, and interosseous membrane
Insertion: Distal phalanx of thumb
Action: Flexes thumb
Innervation: Median nerve, C8 and T1
Flexor Digitorum Profundus
Origin: Anteromedial surface of ulna, interosseous membrane, and coronoid process
Insertion: Distal phalanges of fingers 2-5
Action: Sole muscle that flexes distal phalanges; assists in wrist flexion
Innervation: Anterior interosseous and ulnar nerves
Pronator Quadratus
Origin: Distal portion of anterior ulnar surface
Insertion: Anterior surface of radius, distal end
Action: Pronates forearm
Innervation: Median nerve and anterior interosseous nerve (roots C8 and T1)
Extensor Carpi Radialis Longus
Origin: Lateral supracondylar ridge of humerus
Insertion: Base of metacarpal 2
Action: Extends and abducts wrist
Innervation: Radial nerve
Extensor Carpi Radialis Brevis
Origin: Lateral epicondyle of humerus
Insertion: Base of metacarpal 3
Action: Extends and abducts wrist; steadies wrist during finger flexion
Innervation: Radial nerve
Extensor Digitorum
Origin: Lateral epicondyle of humerus
Insertion: By four tendons into distal phalanges of fingers 2-5
Action: Prime mover of finger extension; extends wrist; can flare (abduct) fingers
Innervation: Radial nerve
Extensor Carpi Ulnaris
Origin: Lateral epicondyle of humerus; posterior border of ulna
Insertion: Base of metacarpal 5
Action: Extends and adducts wrist
Innervation: Radial nerve
Extensor Pollicis Longus and Brevis
Origin: Dorsal shaft of ulna and radius, interosseous membrane
Insertion: Base of distal phalanx of thumb (longus) and proximal phalanx of thumb (brevis)
Action: Extend thumb
Innervation: Radial nerve, C7 and C8
Abductor Pollicis Longus
Origin: Posterior surface of radius and ulna; interosseous membrane
Insertion: Metacarpal 1 and trapezium
Action: Abducts and extends thumb
Innervation: Posterior interosseous nerve (deep radial)
Supinator
Origin: Lateral epicondyle of humerus; proximal ulna
Insertion: Proximal end of radius
Action: Acts with biceps brachii to supinate forearm; antagonist of pronator muscles
Innervation: Posterior interosseous nerve (deep radial)